Obesity is Not Associated with Perioperative Adverse Events in Patients Undergoing Complex Revision Surgery for the Thoracolumbar Spine

Obesity is Not Associated with Perioperative Adverse Events in Patients Undergoing Complex Revision Surgery for the Thoracolumbar Spine | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Obesity is Not Associated with Perioperative Adverse Events in Patients Undergoing Complex Revision Surgery for the Thoracolumbar Spine Takashi Hirase, Jeremiah F. Ling, Varan Haghshenas, Richard Fuld 3rd, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-789945/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 11 You are reading this latest preprint version Abstract Study Design: Retrospective cohort study Objective : This study sought to determine the relationship between obesity and perioperative adverse events (AEs) with patients undergoing complex revision thoracolumbar spine surgery while controlling for psoas muscle index (PMI) as a confounding variable. Methods: Between May 2016 and February 2020, a retrospective analysis of individuals undergoing complex revision surgery of the thoracolumbar spine was performed at a single institution. Obesity was defined as BMI ≥ 30.0 kg/m 2 . PMI < 500 mm 2 /m 2 for males and 10 was used to define complex revision surgery. A multivariable logistic regression model was used to ascertain the effects of sarcopenia, obesity, age, and gender on the likelihood of the occurrence of any AE. Results: The study included 114 patients. 54 patients were in the obese cohort and 60 patients in the non-obese cohort. There was not a significant difference in perioperative outcomes of both the obese and non-obese patients. Multivariable analysis demonstrated that sarcopenic individuals had a significantly higher likelihood for an AE than non-sarcopenic individuals (OR: 7.53, 95% CI: 3.05-18.60). Obesity did not have a significant effect in predicting AEs. Conclusions: Obesity is not associated with perioperative AEs, 30-day readmission rates, 30-day re-operation rates, rate of discharge to a facility, or post-operative length of stay (LOS) among patients undergoing complex revision thoracolumbar spine surgery. Level of Evidence: III Orthopedics obesity revision thoracolumbar spine surgery sarcopenia complex predictor. Introduction Currently, over 100 million adults living in the United States are considered obese and overweight. 1 The NIH utilizes body mass index (BMI) as a parameter of categorizing weight status, calculating BMI using body weight in kilograms dived by height in meters squared. 2 Obesity is a chronic disease recognized clinically as having a BMI > 30 in adults and has association with other comorbidities such as Type 2 Diabetes, cardiovascular disease and dyslipidemia. 3 The impact of obesity on spinal surgeries remains unclear, and complications related to obesity have been reported in some studies. 4 , 5 Studies by Shamji et al. and Manson et al. found that obesity is associated with increased resources and perioperative transfusion requirements after elective thoracolumbar spine surgery; however, they reported no other associations between obesity and increased adverse events (AEs). 6 , 7 Another study by Yadla et al. investigating outcomes after primary elective thoracolumbar spine surgery found no associates between BMI and increased AEs. 8 Furthermore, a more recent study by Varshneya et al. reported that although obesity may be associated with overall health burdens outside of the perioperative environment, there is no significant relationship attributed between obesity and AEs after primary thoracolumbar deformity surgery. 9 Revision thoracolumbar spine surgeries have been associated with significantly higher perioperative AEs compared with primary surgeries. 10 – 12 An increase in surgical complexity has also been associated with higher perioperative AEs in spine surgery. 13 Therefore, identifying specific prognostic indicators for complex revision thoracolumbar spine surgery is important in order to stratify pre-operative risk for these patients. A recent study by Hirase et al. demonstrated that sarcopenia, defined by psoas muscle index (PMI) below 500 mm 2 /m 2 for males and 412 mm 2 /m 2 for females, is predictive of increased perioperative AEs among patients undergoing complex revision thoracolumbar spine surgery. 14 However, this study reported a significantly lower BMI among sarcopenic patients, indicating the presence of a possible confounding factor for predicting perioperative AEs within this patient cohort. Our understanding is that there are no previous studies that evaluate the effect of obesity status on patients undergoing complex revision thoracolumbar spine surgery. Thus, the purpose of this study was to elucidate the relationship between obesity and perioperative AEs among patients undergoing complex revision thoracolumbar spine surgery while controlling for PMI as a confounding variable. Materials And Methods The same patient cohort and similar methodologies were utilized from our previous publication by Hirase et al. 14 The local institutional review board approved the study procedure on April 13, 2020. Due to the retrospective observational nature of this study, the informed consent was waived. Study Population Between May 2016 and February 2020, a retrospective analysis was performed at a single institution of patients receiving complex revision thoracolumbar spine surgery by three board certified fellowship-trained orthopaedic spine surgeons. The same inclusion and exclusion criteria for the same cohort of patients from our previous publication by Hirase et al. was applied for this study. 14 Any patients age 18 or above undergoing complex revision thoracolumbar spine surgery were included. Any history of prior surgical intervention of the same vertebral level was defined as revision surgery. A Spine Surgical Invasiveness Index (SSII) > 10 was used to define complex surgery. 18 Patients lacking a pre-operative CT or MRI of the lumbar spine obtained at our facility within six months of surgery, poor image quality, pre-operative MRI or CT acquired at any outside facilities, clinical evidence of L1 or L2 nerve root compression, a history of previous surgical treatment to or through the psoas muscle, and coronal deformity greater than 20 degrees were excluded as mentioned in our previous study. 14 Data Collection Electronic medical records were utilized retrospectively to obtain demographic data including age, gender, BMI, American Anesthesiologists’ Society (ASA) class, comorbidities, indication for revision operation, baseline ambulation status, and presence of neurologic deficits. BMI ≥ 30.0 kg/m 2 was used to define obesity. Intraoperative data was acquired which included estimated blood loss (EBL) and operative time defined as time of incision to post-operative dressing placement. SSII, a verified method of evaluation and comparison regarding spine surgery complexity was used, with a range of 0–48, which accounts for surgical approaches and the amount of decompressed, fused, and instrumented vertebral levels. 18 In regard to the included surgical population with revision surgeries, only the additional levels of fusion, instrumentation, or decompression were accounted for the SSII calculation as previously stated. 14 Each patients’ primary surgery SSII score was also obtained. Assessment Of Sarcopenia PMI was used to analyze sarcopenia, which was calculated by measuring the total cross-sectional area (CSA) of the bilateral psoas muscles at the L3 vertebral body using the pre-operative T1 weighted MRI or CT normalized to body height 2 (mm 2 /m 2 ). The total CSA was measured using OsiriX DICOM Viewer software (Version 11.0, Bernex, Switzerland) by manual outlining the bilateral psoas muscles at the first axial cut, done in the craniocaudal direction where both transverse processes are visible at the L3 level. 14 , 15 All of the images were obtained at a single institution with the same scanning protocols ensuring identical scanning thickness among all images analyzed. Three separate reviewers performed all measurements to improve interobserver reliability. Each measurement was acquired three times by all reviewers to improve intraobserver reliability. Intraclass correlation coefficient (ICC) was used to assess interobserver and intraobserver reliabilities, where an ICC above 0.90 signifies excellent agreement, between 0.75 and 0.90 signifies good agreement, between 0.5 and 0.75 signifies moderate agreement, and below 0.5 signifies poor agreement. 16 Each of the mean values obtained by the three reviewers was divided by the square of patient height to calculate the PMI as previously described. 14 To minimize the risk of bias, all reviewers were blinded to their respective measurements as well as to patient demographics and outcomes. Sarcopenia was defined as PMI < 500 mm 2 /m 2 for males and < 412 mm 2 /m 2 for females as previously defined. 14 Outcome Measures Retrospective analysis of electronic medical records were used to review all perioperative outcomes. The primary outcome measures were perioperative AEs which included post-operative anemia that required transfusion, cardiac complication (cardiac arrest and myocardial infarction), sepsis, wound complication (wound dehiscence and deep wound infection), acute kidney injury (AKI), delirium, intra-operative dural tear, pneumonia, urinary tract infection (UTI), urinary retention, epidural hematoma, and deep vein thrombosis (DVT). The secondary outcome measures used were 30-day readmission rates, 30-day re-operation rates, in-hospital mortality rates, discharge disposition (home vs facility) and post-operative hospital length of stay (LOS). The number of days from surgery (or the last surgery if staged procedure) to discharge to either home or facility was used to defined postoperative LOS. Statistical Analysis SPSS statistical software (Version 25.0; SPSS, Inc, Chicago, IL) was utilized to perform data analysis. The Chi-Square or Fisher’s exact test and continuous data was used to analyze categorical data and was further analyzed using Two-tailed student t- test. Continuous variables with non-normal distribution was analyzed using the Mann-Whitney U test. Statistical significance was set to p-value < 0.05. The odds ratio (OR) with 95% confidence interval (CI) was calculated for comparing perioperative outcomes. Post hoc power analysis with a two-tailed alpha of 0.05 was performed between obese and non-obese groups to evaluate the power of detecting differences between patients experiencing any perioperative. A multivariable logistic regression model was used to determine the effects of sarcopenia, obesity, age, and gender on the likelihood of the occurrence of any AE. Results In total, there were 166 patients that met the inclusion criteria and 52 were removed based on the exclusion criteria. Final analysis included 114 patients (mean age 60.1 ± 15.4 years, 45 males, 69 females). The overall mean PMI was 495.0 ± 182.9 mm 2 /m 2 . Interobserver and intraobserver reliabilities were considered excellent with ICC of 0.908 (95% CI 0.862–0.944) and 0.962 (95% CI 0.928–0.975), respectively. 54 patients were in the obese cohort and 60 patients in the non-obese cohort. The obese patients had a higher BMI and PMI compared to non-obese patients; otherwise, there were no significant differences in baseline demographics, comorbidities, presence of motor/sensory deficits, ambulatory status, indication for reoperation, or SSII between the two groups (Table 1 ). No significant difference between the perioperative outcomes was found among the obese and non-obese patients (Table 2 ). Table 1 Demographics and Characteristics of the Study Population Variable Obese (n = 54) Non-obese (n = 60) P-value BMI (kg/m 2 ), mean ± SD (range) 36.2 ± 5.4 (30.0–51.7) 25.8 ± 3.0 (16.0–29.8) < 0.001* Male, n (%) 25 (46.3) 20 (33.3) 0.159 Age (y), mean ± SD (range) 61.4 ± 12.0 (20–77) 62.1 ± 13.3 (25–80) 0.768 ASA Class, mean ± SD (range) 2.78 ± 0.54 (2–4) 2.57 ± 0.65 (1–4) 0.060 PMI (mm 2 /m 2 ), mean ± SD (range) 545.3 ± 174.4 (190.0–941.7) 449.6 ± 179.8 (152.2–940.4) 0.004* Comorbidities, n (%) DM 11 (20.4) 10 (16.7) 0.611 Smoking 7 (13.0) 7 (11.7) 0.834 Cardiac (CHF, CAD, Atrial fibrillation) 11 (20.4) 14 (23.3) 0.704 CKD 7 (13.0) 9 (15.0) 0.757 COPD 19 (35.2) 15 (25.0) 0.234 CVA 1 (1.9) 1 (1.7) 0.936 PVD 2 (3.7) 1 (1.7) 0.497 Cancer 4 (7.4) 2 (3.3) 0.332 No pre-operative motor deficits, n (%) 41 (75.9) 39 (65.0) 0.204 No pre-operative sensory deficits, n (%) 35 (64.8) 30 (50.0) 0.110 Ambulatory status, n (%) Ambulate without assistive device 16 (29.6) 20 (33.3) 0.674 Ambulate with assistive device 30 (55.6) 23 (38.3) 0.066 Wheelchair bound 8 (14.8) 7 (11.7) 0.617 Not recorded 4 (7.4) 6 (10.0) 0.624 Indication for reoperation Spinal stenosis 22 (40.7) 29 (48.3) 0.418 Disc disease 13 (24.1) 16 (26.7) 0.749 Spondylolisthesis 14 (25.9) 14 (23.3) 0.749 Trauma 3 (5.6) 2 (3.3) 0.562 Deformity 25 (46.3) 27 (45.0) 0.889 Adjacent segment disease 22 (40.7) 24 (40.0) 0.936 Pseudarthrosis 27 (50.0) 30 (50.0) 1.000 HNP 3 (5.6) 3 (5.0) 0.897 Infection 2 (3.7) 1 (1.7) 0.497 SSII of primary surgery, mean ± SD (range) 11.9 ± 6.3 (3–32) 13.9 ± 5.9 (3–32) 0.067 SSII of revision surgery, mean ± SD (range) 25.6 ± 13.7 (11–48) 25.8 ± 11.3 (11–48) 0.943 *Statistically significant values PMI, psoas muscle index; ASA, American Society of Anesthesiologists; BMI, body mass index; DM, diabetes mellitus; CHF, congestive heart failure; CAD, coronary artery disease; CKD, chronic kidney disease; COPD, chronic obstructive pulmonary disease; CVA, cerebrovascular accident; PVD, peripheral vascular disease; HNP, herniated nucleus pulposus; SSII, spine surgical invasiveness index 18 Table 2 Comparison of Perioperative Outcomes Variable Obese (N = 54) Non-obese (n = 60) P Value OR (95% CI) Operative time (minutes), mean ± SD (range) 387.1 ± 224.3 (108–1160) 372.2 ± 172.7 (122–937) 0.693 N/A EBL (mL), mean ± SD (range) 1235.5 ± 1792.4 (75-12321) 856.2 ± 744.0 (50-4600) 0.152 N/A EBL > 1 L, n (%) 22 (40.7) 19 (31.7) 0.490 1.29 (0.63–2.63) Intraoperative pRBC transfusion units, mean ± SD (range) 2.2 ± 2.6 (0–15) 1.7 ± 1.6 (0–8) 0.238 N/A Post-operative LOS (days), mean ± SD (range) 7.1 ± 5.6 (2–36) 6.3 ± 4.0 (1–19) 0.375 N/A Discharge Disposition, n (%) Home 20 (37.0) 19 (31.7) 0.547 1.27 (0.59–2.76) Facility 34 (63.0) 41 (68.3) 0.547 0.79 (0.36–1.71) 30-day Reoperation, n (%) 4 (7.4) 5 (8.3) 0.855 0.88 (0.22–3.46) 30-day Readmission, n (%) 4 (7.4) 6 (10.0) 0.626 0.72 (0.19–2.70) In-hospital mortality, n (%) 0 (0.0) 1 (1.7) 0.539 0.36 (0.01–9.12) Perioperative Adverse Events, n (%) Any adverse events 22 (40.7) 33 (55.0) 0.130 0.56 (0.27–1.18) Post-op anemia requiring transfusion 8 (14.8) 18 (30.0) 0.058 0.41 (0.16–1.03) Cardiac (cardiac arrest, MI) 1 (1.9) 2 (3.3) 0.487 0.55 (0.05–6.21) Sepsis 0 (0.0) 1 (1.7) 0.539 0.36 (0.01–9.12) Wound complication (dehiscence, infection) 4 (7.4) 7 (11.7) 0.763 0.61 (0.17–2.20) Delirium 2 (3.7) 8 (13.3) 0.089 0.25 (0.05–1.23) Intra-op dural tear 1 (1.9) 3 (5.0) 0.387 0.36 (0.04–3.55) AKI 5 (9.3) 7 (11.7) 0.676 0.77 (0.23–2.59) Pneumonia 3 (5.6) 6 (10.0) 0.386 0.53 (0.13–2.23) UTI 2 (3.7) 9 (15.0) 0.059 0.21 (0.04–1.06) Urinary retention 4 (7.4) 3 (5.0) 0.595 1.52 (0.32–7.12) Epidural hematoma 2 (3.7) 0 (0.0) 0.262 5.76 (0.27–122.7) DVT 4 (7.4) 6 (10.0) 0.626 0.72 (0.19–2.70) Nerve injury or paralysis 2 (3.7) 0 (0.0) 0.262 5.76 (0.27–122.7) OR, odds ratio; EBL, estimated blood loss; SD, standard deviation; CI, confidence interval; pRBC, packed red blood cells; LOS, length of stay; MI, myocardial infarction; AKI, acute kidney injury; UTI, urinary tract infection; DVT, deep vein thrombosis Using the prior defined definition of sarcopenia as PMI < 500 mm 2 /m 2 for males and < 412 mm 2 /m 2 for females, 15 patients were considered obese and sarcopenic and 34 patients were considered non-obese and sarcopenic. 14 No significant difference in perioperative outcomes was found between these patients (Table 3 ). 39 patients were considered obese and non-sarcopenic and 26 patients were considered non-obese and non-sarcopenic. No significant difference in perioperative outcomes was found between these patients (Table 4 ). Table 3 Comparison of Perioperative Outcomes among Sarcopenic Patients Variable Obese + Sarcopenic (N = 15) Non-obese + Sarcopenic (n = 34) P Value OR (95% CI) Operative time (minutes), mean ± SD (range) 387.9 ± 209.4 (186–993) 408.9 ± 165.4 (198–937) 0.734 N/A EBL (mL), mean ± SD (range) 1118.3 ± 1071.8 (150–3500) 926.2 ± 605.6 (50-2400) 0.524 N/A EBL > 1 L, n (%) 7 (46.7) 14 (41.2) 0.822 1.13 (0.38–3.38) Intraoperative pRBC transfusion units, mean ± SD (range) 2.2 ± 2.2 (0–7) 1.8 ± 1.4 (0–6) 0.278 N/A Post-operative LOS (days), mean ± SD (range) 8.1 ± 3.8 (3–14) 7.2 ± 4.4 (2–19) 0.460 N/A Discharge Disposition, n (%) Home 3 (20.0) 4 (11.8) 0.453 1.88 (0.36–9.66) Facility 12 (80.0) 30 (88.2) 0.453 0.53 (0.10–2.75) 30-day Reoperation, n (%) 3 (20.0) 4 (11.8) 0.453 1.88 (0.36–9.66) 30-day Readmission, n (%) 3 (20.0) 5 (14.7) 0.645 1.45 (0.30–7.05) In-hospital mortality, n (%) 0 (0.0) 1 (2.9) 0.844 0.72 (0.03–18.7) Perioperative Adverse Events, n (%) Any adverse events 10 (66.7) 26 (76.5) 0.476 0.62 (0.16–2.34) Post-op anemia requiring transfusion 5 (33.3) 15 (44.1) 0.481 0.63 (0.18–2.25) Cardiac (cardiac arrest, MI) 1 (6.7) 1 (2.9) 0.554 2.36 (0.14–40.4) Sepsis 0 (0.0) 1 (2.9) 0.844 0.72 (0.03–18.7) Wound complication (dehiscence, infection) 3 (20.0) 6 (17.6) 0.845 1.17 (0.25–5.45) Delirium 2 (13.3) 7 (20.6) 0.549 0.59 (0.11–3.26) Intra-op dural tear 1 (6.7) 2 (5.9) 0.916 1.14 (0.10–13.7) AKI 3 (20.0) 9 (26.5) 0.628 0.69 (0.16–3.04) Pneumonia 1 (6.7) 6 (17.6) 0.330 0.33 (0.04–3.05) UTI 2 (13.3) 7 (20.6) 0.549 0.59 (0.11–3.26) Urinary retention 2 (13.3) 3 (8.8) 0.633 1.59 (0.24–10.7) Epidural hematoma 1 (6.7) 0 (0.0) 0.237 7.14 (0.27–185.7) DVT 3 (20.0) 5 (14.7) 0.645 1.45 (0.30–7.05) Nerve injury or paralysis 1 (6.7) 0 (0.0) 0.237 7.14 (0.27–185.7) OR, odds ratio; EBL, estimated blood loss; SD, standard deviation; CI, confidence interval; LOS, length of stay; MI, myocardial infarction; AKI, acute kidney injury; UTI, urinary tract infection; DVT, deep vein thrombosis Table 4 Comparison of Perioperative Outcomes Among Non-Sarcopenic Patients Variable Obese + Non-Sarcopenic (N = 39) Non-Obese + Non-Sarcopenic (N = 26) P Value OR (95% CI) Operative time (minutes), mean ± SD (range) 386.8 ± 232.4 (108–1160) 324.1 ± 173.3 (122–847) 0.218 N/A EBL (mL), mean ± SD (range) 1280.6 ± 2012.5 (75-12321) 764.7 ± 898.3 (50-4600) 0.166 N/A EBL > 1 L, n (%) 15 (38.5) 5 (19.2) 0.228 2.00 (0.65–6.17) Intraoperative pRBC transfusion units, mean ± SD (range) 2.2 ± 2.8 (0–15) 1.6 ± 1.8 (0–8) 0.135 N/A Post-operative LOS (days), mean ± SD (range) 6.8 ± 6.1 (2–36) 5.2 ± 3.1 (1–13) 0.176 N/A Discharge Disposition, n (%) Home 17 (43.6) 15 (57.7) 0.267 0.57 (0.21–1.55) Facility 22 (56.4) 11 (42.3) 0.267 1.76 (0.65–4.81) 30-day Reoperation, n (%) 1 (2.6) 1 (3.8) 0.771 0.66 (0.04-11.0) 30-day Readmission, n (%) 1 (2.6) 1 (3.8) 0.771 0.66 (0.04-11.0) In-hospital mortality, n (%) 0 (0.0) 0 (0.0) 0.843 0.67 (0.01–34.9) Perioperative Adverse Events, n (%) Any adverse events 12 (30.8) 7 (26.9) 0.739 1.21 (0.40–3.63) Post-op anemia requiring transfusion 3 (7.7) 3 (11.5) 0.602 0.64 (0.12–3.44) Cardiac (cardiac arrest, MI) 0 (0.0) 1 (3.8) 0.353 0.22 (0.01–5.49) Sepsis 0 (0.0) 0 (0.0) 0.843 0.67 (0.01–34.9) Wound complication (dehiscence, infection) 1 (2.6) 1 (3.8) 0.771 0.66 (0.04-11.0) Delirium 0 (0.0) 1 (3.8) 0.353 0.22 (0.01–5.49) Intra-op dural tear 0 (0.0) 1 (3.8) 0.353 0.22 (0.01–5.49) AKI 4 (10.3) 0 (0.0) 0.208 6.72 (0.35–130.3) Pneumonia 2 (5.1) 0 (0.0) 0.421 3.53 (0.16–76.6) UTI 0 (0.0) 0 (0.0) 0.843 0.67 (0.01–34.9) Urinary retention 2 (5.1) 0 (0.0) 0.421 3.53 (0.16–76.6) Epidural hematoma 1 (2.6) 0 (0.0) 0.661 2.06 (0.08–52.7) DVT 1 (2.6) 1 (3.8) 0.771 0.66 (0.04-11.0) Nerve injury or paralysis 1 (2.6) 0 (0.0) 0.661 2.06 (0.08–52.7) OR, odds ratio; EBL, estimated blood loss; SD, standard deviation; CI, confidence interval; LOS, length of stay; MI, myocardial infarction; AKI, acute kidney injury; UTI, urinary tract infection; DVT, deep vein thrombosis The multivariable logistic regression model was statistically significant, χ 2 (4) = 28.572, p < .0005. 72.8% of the cases were correctly classified by the model, which also explained 29.6% (Nagelkerke R 2 ) of the variance in any AE. The model revealed that sarcopenic individuals had a significantly higher likelihood for an AE than non-sarcopenic individuals (OR: 7.53, 95% CI: 3.05–18.60). Obesity, age, and gender did not have a significant effect in predicting AEs (Table 5 ). The post hoc power analysis between the obese and non-obese groups calculated a 95.2% power of detecting differences between patients experiencing any perioperative AEs. Table 5 Multivariable Logistic Regression Model to Assess Effects on Adverse Events Variable β SE P Value Adjusted OR (95% CI) Sarcopenia 2.019 0.461 < 0.001* 7.53 (3.05–18.6) Obesity 0.040 0.452 0.929 1.04 (0.43–2.52) Age 0.033 0.018 0.065 1.03 (1.00-1.07) Gender -0.066 0.444 0.882 0.94 (0.39–2.24) *Statistically significant values SE, standard error; OR, odds ratio; CI, confidence interval Discussion In this study, the use of BMI as a predictor of perioperative AEs among patients undergoing complex thoracolumbar spine surgery was investigated. The multivariable logistic regression model confirmed that sarcopenic individuals were at a significantly higher likelihood to experience AE compared to non-sarcopenic individuals; however, there were no associations between BMI and perioperative AEs, 30-day readmission rates, 30-day re-operation rates, rate of discharge to a facility, or post-operative LOS among patients undergoing complex revision thoracolumbar spine surgery. The relationship between obesity and perioperative AEs has been an area of debate over the past decade. Various studies have shown a significantly higher risk of AEs among obese patients after thoracolumbar surgery. 17 – 21 The most recent study by Passias et al. determined that obese patients with a prior bariatric surgery had a significantly lower complication rate after thoracolumbar spine surgery compared with obese patients that did not undergo bariatric surgery. 21 Our findings contradict these series of studies as our analysis demonstrated no significant difference in post-operative AEs between obese and non-obese patients. There are likely multiple reasons that our study had different results. First, our study performed a multivariable analysis with sarcopenia, measured by PMI, which demonstrated a significantly higher association with post-operative AEs. None of the prior studies that investigated the association between obesity and AEs included sarcopenia as a potential confounding variable. Second, our patient cohort consisted solely of complex revision cases, which is a particularly unique population with high complication rates at baseline. From our study analysis, it may be speculated that amongst these complex patients, pre-operative sarcopenia, and the associated debility and frailty, is a much better predictor for post-operative complications compared with the risks associated with obesity. Furthermore, studies have shown that although bariatric surgery is effective at lowering the BMI, this procedure may also induce sarcopenia post-operatively. 22 , 23 Thus, with the known risks of sarcopenia shown within our study, it may be inadvisable to recommend bariatric surgery to improve BMI prior to undergoing complex revision thoracolumbar spine surgery. A particularly important process among patients undergoing complex revision surgeries known to have high perioperative complications is preoperative risk stratification. Our previous study by Hirase et al. identified sarcopenia measured by PMI as a predictor of perioperative AEs among patients undergoing complex revision thoracolumbar spine surgery. 14 Our multivariable analysis within this study confirmed these findings and also demonstrated that obesity is not associated with perioperative AEs within this patient population. This combination of findings will specifically assist spine surgeons during pre-operative counseling and evaluation on two fronts. First, pre-operative optimization and overall conditioning to increase PMI among sarcopenic patients may be beneficial to preventing post-operative AE. Second, obese patients may not benefit from aggressive weight loss prior to these surgeries, particularly, as studies have shown that improper weight loss methods may lead to sarcopenia. 24 , 25 Our study has several limitations. Data accuracy is contingent on charting accuracy due to the retrospective nature of the study and may be susceptible to certain selection bias. Our results obtained from a single-center data may not be completely reflective of outcomes from other institutions due to variations in surgical technique or management. Our study also consisted of a relatively small patient cohort that may have led to underpowering to detect certain associations; however, our post hoc power analysis demonstrated that the absence of observed difference is unlikely due to lack of power. Furthermore, there may have been small discrepancies in inter-scan agreement between CT and MRI scans used to obtain the PMI; however, this is a previously established method with studies showing good inter-scan reliability with an ICC of 0.821. 14 , 26 Thus, to increase the power of the study, patients were included if they received either a CT or an MRI pre-operatively. Furthermore, although this study demonstrates that obesity is not a predictor of post-operative AEs within this surgical population, we cannot directly conclude that weight loss will not be beneficial in preventing post-operative AEs. Therefore, further studies that investigate the external validity of this study may be beneficial prior to application in practice. In spite of the aformentioned limitations, to the best of our knowledge, this is the largest study examining the relationship between obesity and perioperative outcomes among patients receiving complex revision thoracolumbar spine surgery. This study will serve to assist spine surgeons with additional information during pre-operative counseling and evaluation regarding risks and benefits associated with sarcopenia and obesity. For patients undergoing complex revision thoracolumbar spine surgery, our findings may suggest that the benefits of weight loss among obese patients may not outweigh the risk of inducing sarcopenia prior to the operation. Conclusions Obesity is not associated with perioperative AEs, 30-day readmission rates, 30-day re-operation rates, rate of discharge to a facility, or post-operative length of stay (LOS) among patients undergoing complex revision thoracolumbar spine surgery. Abbreviations AEs adverse events; PMI = psoas muscle index; LOS = length of stay; BMI = body mass index; SSII = spine surgical invasiveness index; ASA = American Anesthesiologists’ Society; EMR = electronic medical records; EBL = estimated blood loss; CSA = cross-sectional area; ICC = intraclass correlation coefficient; AKI = acute kidney injury; UTI = urinary tract infection; DVT = deep vein thrombosis; OR = odds ratio; CI = confidence interval Declarations Ethics approval and consent to participate: The study protocol was approved through the Houston Methodist Hospital institutional review board on April 13, 2020 (PRO00024733) with a waiver for informed consent attributed to the study’s retrospective observational nature. Consent for publication: Written informed consent for publication of their clinical details and/or clinical images was obtained from the patient/parent/guardian/ relative of the patient. A copy of the consent form is available for review by the Editor of this journal. Availability of data and material: Available upon request to corresponding author Competing interests: Takashi Hirase, Jeremiah Ling, Varan Haghshenas, Richard Fuld III, David Dong, and B Christoph Meyer declare no potential conflicts of interest with respect to research, authorship, and/or publication of this article. Rex AW Marco has the following disclosures: DePuy, A Johnson & Johnson Company: Paid presenter or speaker; Globus Medical: Paid presenter or speaker; Musculoskeletal Tumor Society: Board or committee member; Stryker: Paid presenter or speaker; Synaptive Medical: Paid presenter or speaker Darrell S Hanson has the following disclosures: DePuy, A Johnson & Johnson Company: IP royalties; Paid consultant; Paid presenter or speaker; Medtronic Sofamor Danek: Paid consultant; Paid presenter or speaker Funding : None Author’s Contributions: All authors made substantial contributions to the conception and design of work and provided final approval of the version to be published. Specific additional individual contribution includes: Takashi Hirase: Interpretation and analysis of data for the work. Drafted the introduction, the overall work outline, and made critical final revisions. Jeremiah Ling: Lead the acquisition of data and drafted the results section. Varan Haghshenas: Drafted a portion of the discussion section and made critical final revisions. Richard Fuld III: Assisted in the acquisition of data and drafted the results section. David Dong: Assisted in the acquisition of data and drafted the results section. Darrell Hanson: Senior surgeon with substantial contribution to design of work and made critical final revisions and approval of the version to be published. B Christoph Meyer: Senior surgeon with substantial contribution to design of work and made critical final revisions and approval of the version to be published. Rex AW Marco: Senior surgeon with substantial contribution to design of work and made critical final revisions and approval of the version to be published Acknowledgements: Takashi Hirase was supported by a Burroughs Wellcome Fund Physician Scientist Institutional Award to the Texas A&M University Academy of Physician Scientists References Flegal KM, Carroll MD, Kuczmarski RJ, & Johnson CL. Overweight and obesity in the United States: prevalence and trends, 1960–1994. Int J Obes Relat Metab Disord. 1998;22(1):39–47. Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults–The Evidence Report. National Institutes of Health. Obes Res. 1998;6 Suppl 2:51S-209S. Purnell, J. Q. Definitions, Classification, and Epidemiology of Obesity. In: K. R. Feingold Anawalt B, Boyce A, Chrousos G, de Herder WW, Dhatariya K, Dungan K, Grossman A, Hershman JM, et. al. 2018. http://www.endotext.org . Accessed Oct 2020. Park, P., Upadhyaya, C., Garton, H. J., & Foley, K. T. The impact of minimally invasive spine surgery on perioperative complications in overweight or obese patients. Neurosurgery. 2008;62(3):693–699. Cao, J., Kong, L., Meng, F., Zhang, Y., & Shen, Y. Impact of obesity on lumbar spinal surgery outcomes. J Clin Neurosci. 2016;28:1–6. Manson, N. A., Green, A. J., & Abraham, E. P. Elevated Patient Body Mass Index Does Not Negatively Affect Self-Reported Outcomes of Thoracolumbar Surgery: Results of a Comparative Observational Study with Minimum 1-Year Follow-Up. Global Spine J. 2016;6(2):108–117. Shamji, M. F., Parker, S., Cook, C., Pietrobon, R., Brown, C., & Isaacs, R. E. Impact of body habitus on perioperative morbidity associated with fusion of the thoracolumbar and lumbar spine. Neurosurger y. 2009;65(3):490–498. Yadla S, Malone J, Campbell PG, Maltenfort MG, Harrop JS, Sharan AD, et al. Obesity and spine surgery: reassessment based on a prospective evaluation of perioperative complications in elective degenerative thoracolumbar procedures. Spine J. 2010;10(7):581–587. Varshneya K, Pangal DJ, Stienen MN, Ho AL, Fatemi P, Medress ZA, et al. Postoperative Complication Burden, Revision Risk, and Health Care Use in Obese Patients Undergoing Primary Adult Thoracolumbar Deformity Surgery. Global Spine J. 2021;11(3):345–350. Kim SS, Michelsen CB. Revision Surgery for failed back surgery syndrome. Spine (Phila Pa 1976). 1992;17(8):957–60. Fritsch EW, Heisel J, Rupp S. The failed back surgery syndrome: reasons, intraoperative findings, and long-term results: a report of 182 operative treatments. Spine (Phila Pa 1976). 1996;21(5):626–33. Sansur CA, Smith JS, Coe JD, Glassman SD, Berven SH, Polly DW Jr, et al. Scoliosis research society morbidity and mortality of adult scoliosis surgery. Spine (Phila Pa 1976). 2011;36(9):E593–7. Camino Willhuber G, Elizondo C, Slullitel P. Analysis of Postoperative Complications in Spinal Surgery, Hospital Length of Stay, and Unplanned Readmission: Application of Dindo-Clavien Classification to Spine Surgery. Global Spine J. 2019;9(3):279–86. Hirase T, Haghshenas V, Bratescu R, Dong D, Kuo PH, Rashid A, et al. Sarcopenia Predicts Perioperative Adverse Events Following Complex Revision Surgery for the Thoracolumbar Spine. Spine J. 2021 Jun;21(6):1001–1009. Moskven E, Bourassa-Moreau E, Charest-Morin R, Flexman A, Street J. The impact of frailty and sarcopenia on postoperative outcomes in adult spine surgery. A systematic review of the literature. Spine J. 2018; 18(12):2354–69. Koo TK, Li MY. A Guideline of Selecting and Reporting Intraclass Correlation Coefficients for Reliability Research. J Chiropr Med. 2016;15(2):155–63. Knutsson BB, Michaëlsson K, Sandén B. Obesity is associated with inferior results after surgery for lumbar spinal stenosis: a study of 2633 patients from the Swedish spine register. Spine (Phila Pa 1976). 2013;38(5):435–441 Marquez-Lara A, Nandyala SV, Sankaranarayanan S, Noureldin M, Singh K. Body mass index as a predictor of complications and mortality after lumbar spine surgery. Spine (Phila Pa 1976). 2014;39(10):798–804 Buerba RA, Fu MC, Gruskay JA, Long WD 3rd, Grauer JN. Obese class III patients at significantly greater risk of multiple complications after lumbar surgery: an analysis of 10,387 patients in the ACS NSQIP database. Spine J. 2013;14(9):2008–2018 Christou NV, Sampalis JS, Liberman M, Look D, Auger S, McLean AP, MacLean LD. Surgery decreases long-term mortality, morbidity, and health care use in morbidly obese patients. Ann Surg. 2004;240(3):416-23-4 Passias PG, Horn SR, Vasquez-Montes D, Shepard N, Segreto FA, Bortz CA, et al. Prior bariatric surgery lowers complication rates following spine surgery in obese patients. Acta Neurochir (Wien). 2018;160(12):2459–2465. Pekař M, Pekařová A, Bužga M, Holéczy P, Soltes M. The risk of sarcopenia 24 months after bariatric surgery - assessment by dual energy X-ray absorptiometry (DEXA): a prospective study. Wideochir Inne Tech Maloinwazyjne. 2020 Dec;15(4):583–587. Voican CS, Lebrun A, Maitre S, Lainas P, Lamouri K, Njike-Nakseu M, et al. Predictive score of sarcopenia occurrence one year after bariatric surgery in severely obese patients. PLoS One. 2018;13(5):e0197248. Miller SL, Wolfe RR. The danger of weight loss in the elderly. J Nutr Health Aging. 2008;12(7):487–91. Tournadre A, Vial G, Capel F, Soubrier M, Boirie Y. Sarcopenia. Joint Bone Spine. 2019;86(3):309–314. Park J, Gil JR, Shin Y, Won SE, Huh J, You MW, Park HJ, et al. Reliable and robust method for abdominal muscle mass quantification using CT/MRI: An explorative study in healthy subjects. PLoS One. 2019;14(9):e0222042. Additional Declarations Competing interest reported. Rex AW Marco has the following disclosures: DePuy, A Johnson & Johnson Company: Paid presenter or speaker; Globus Medical: Paid presenter or speaker; Musculoskeletal Tumor Society: Board or committee member; Stryker: Paid presenter or speaker; Synaptive Medical: Paid presenter or speaker Darrell S Hanson has the following disclosures: DePuy, A Johnson & Johnson Company: IP royalties; Paid consultant; Paid presenter or speaker; Medtronic Sofamor Danek: Paid consultant; Paid presenter or speaker Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Major revision 21 Mar, 2022 Reviews received at journal 12 Feb, 2022 Reviewers agreed at journal 12 Feb, 2022 Reviews received at journal 16 Jan, 2022 Reviewers agreed at journal 11 Jan, 2022 Reviewers agreed at journal 16 Dec, 2021 Reviewers invited by journal 31 Aug, 2021 Editor assigned by journal 31 Aug, 2021 Editor invited by journal 31 Aug, 2021 Submission checks completed at journal 31 Aug, 2021 First submitted to journal 07 Aug, 2021 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-789945","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":49094913,"identity":"eddcdf64-15fb-4c03-95a4-870302dc7c47","order_by":0,"name":"Takashi Hirase","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABH0lEQVRIiWNgGAWjYDACCcYGECVngBDiASIDHMpB0lAtxmA1B0AEG0SLBG4tEDpxA6oWBtxa7KWb2z78+GOTvp29x/jzh4o70fzyvQcfvCmoq2Ng7338ApstMgebZ/a2peXu7DljJnHgzLPcmW18yYZzDA5LMPAcN7PA6rDEZgbehsO5G27kmDEcbAMyjvGYSfMYHJBgkEhjwxYKIC2Mf/78Tze4kWP8AaRlP0RLHV4tzDxsBxKAWgwkwLawgbUwg7QwP8Cm5QZQi2xbsuGGM8fKJM6cOZw741iOMcgvkm08x9iwhRj7jPTHjG/+2MkbHG/e/KGi4nBuf/MZwwdv/tTx87O3MX/AFdLYAdAKNpyRgxOQassoGAWjYBQMTwAA7/FkxFIht9QAAAAASUVORK5CYII=","orcid":"","institution":"Houston Methodist Hospital","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Takashi","middleName":"","lastName":"Hirase","suffix":""},{"id":49094916,"identity":"f453decc-a23b-4021-b838-8ad0e66752c0","order_by":1,"name":"Jeremiah F. Ling","email":"","orcid":"","institution":"Texas A\u0026M University Health Science Center College of Medicine","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Jeremiah","middleName":"F.","lastName":"Ling","suffix":""},{"id":49094917,"identity":"631b4a36-bcc1-414d-b25c-f6cfb612cadb","order_by":2,"name":"Varan Haghshenas","email":"","orcid":"","institution":"Houston Methodist Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Varan","middleName":"","lastName":"Haghshenas","suffix":""},{"id":49094919,"identity":"14ee54d4-cf5a-4827-b956-632706db2230","order_by":3,"name":"Richard Fuld 3rd","email":"","orcid":"","institution":"Houston Methodist Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Richard","middleName":"Fuld","lastName":"3rd","suffix":""},{"id":49094920,"identity":"b75d28fb-2f9e-4440-a34a-b19e68837e28","order_by":4,"name":"David Dong","email":"","orcid":"","institution":"Houston Methodist Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"David","middleName":"","lastName":"Dong","suffix":""},{"id":49094921,"identity":"45e5c4d9-b24e-4a3b-8c86-684907bb3185","order_by":5,"name":"Darrell S. Hanson","email":"","orcid":"","institution":"Houston Methodist Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Darrell","middleName":"S.","lastName":"Hanson","suffix":""},{"id":49094922,"identity":"023ecfe0-13f3-4a58-ab7b-f0a49693095d","order_by":6,"name":"B. Christoph Meyer","email":"","orcid":"","institution":"Houston Methodist Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"B.","middleName":"Christoph","lastName":"Meyer","suffix":""},{"id":49094923,"identity":"c05457ae-551f-449d-94ee-cba80523a7a1","order_by":7,"name":"Rex A.W. Marco","email":"","orcid":"","institution":"Houston Methodist Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Rex","middleName":"A.W.","lastName":"Marco","suffix":""}],"badges":[],"createdAt":"2021-08-07 20:43:59","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-789945/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-789945/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":13712314,"identity":"3ad62b9a-e26b-49c9-89fc-170472b5b692","added_by":"auto","created_at":"2021-09-17 14:27:41","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":457300,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-789945/v1/1adacc4a-d3db-434f-a11e-99b22ccf59d0.pdf"}],"financialInterests":"Competing interest reported. Rex AW Marco has the following disclosures:\nDePuy, A Johnson \u0026 Johnson Company: Paid presenter or speaker; Globus Medical: Paid presenter or speaker; Musculoskeletal Tumor Society: Board or committee member; Stryker: Paid presenter or speaker; Synaptive Medical: Paid presenter or speaker\n\nDarrell S Hanson has the following disclosures:\nDePuy, A Johnson \u0026 Johnson Company: IP royalties; Paid consultant; Paid presenter or speaker; Medtronic Sofamor Danek: Paid consultant; Paid presenter or speaker","formattedTitle":"Obesity is Not Associated with Perioperative Adverse Events in Patients Undergoing Complex Revision Surgery for the Thoracolumbar Spine","fulltext":[{"header":"Introduction","content":"\u003cp\u003eCurrently, over 100\u0026nbsp;million adults living in the United States are considered obese and overweight.\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e The NIH utilizes body mass index (BMI) as a parameter of categorizing weight status, calculating BMI using body weight in kilograms dived by height in meters squared.\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e Obesity is a chronic disease recognized clinically as having a BMI\u0026thinsp;\u0026gt;\u0026thinsp;30 in adults and has association with other comorbidities such as Type 2 Diabetes, cardiovascular disease and dyslipidemia.\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e The impact of obesity on spinal surgeries remains unclear, and complications related to obesity have been reported in some studies.\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e,\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e Studies by Shamji et al. and Manson et al. found that obesity is associated with increased resources and perioperative transfusion requirements after elective thoracolumbar spine surgery; however, they reported no other associations between obesity and increased adverse events (AEs).\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e,\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e Another study by Yadla et al. investigating outcomes after primary elective thoracolumbar spine surgery found no associates between BMI and increased AEs.\u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e Furthermore, a more recent study by Varshneya et al. reported that although obesity may be associated with overall health burdens outside of the perioperative environment, there is no significant relationship attributed between obesity and AEs after primary thoracolumbar deformity surgery.\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eRevision thoracolumbar spine surgeries have been associated with significantly higher perioperative AEs compared with primary surgeries.\u003csup\u003e\u003cspan additionalcitationids=\"CR11\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e An increase in surgical complexity has also been associated with higher perioperative AEs in spine surgery.\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e Therefore, identifying specific prognostic indicators for complex revision thoracolumbar spine surgery is important in order to stratify pre-operative risk for these patients. A recent study by Hirase et al. demonstrated that sarcopenia, defined by psoas muscle index (PMI) below 500 mm\u003csup\u003e2\u003c/sup\u003e/m\u003csup\u003e2\u003c/sup\u003e for males and 412 mm\u003csup\u003e2\u003c/sup\u003e/m\u003csup\u003e2\u003c/sup\u003e for females, is predictive of increased perioperative AEs among patients undergoing complex revision thoracolumbar spine surgery.\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e However, this study reported a significantly lower BMI among sarcopenic patients, indicating the presence of a possible confounding factor for predicting perioperative AEs within this patient cohort. Our understanding is that there are no previous studies that evaluate the effect of obesity status on patients undergoing complex revision thoracolumbar spine surgery. Thus, the purpose of this study was to elucidate the relationship between obesity and perioperative AEs among patients undergoing complex revision thoracolumbar spine surgery while controlling for PMI as a confounding variable.\u003c/p\u003e"},{"header":"Materials And Methods","content":"\u003cp\u003eThe same patient cohort and similar methodologies were utilized from our previous publication by Hirase et al.\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e The local institutional review board approved the study procedure on April 13, 2020. Due to the retrospective observational nature of this study, the informed consent was waived.\u003c/p\u003e\n\u003ch2\u003eStudy Population\u003c/h2\u003e\n\u003cp\u003eBetween May 2016 and February 2020, a retrospective analysis was performed at a single institution of patients receiving complex revision thoracolumbar spine surgery by three board certified fellowship-trained orthopaedic spine surgeons. The same inclusion and exclusion criteria for the same cohort of patients from our previous publication by Hirase et al. was applied for this study.\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e Any patients age 18 or above undergoing complex revision thoracolumbar spine surgery were included. Any history of prior surgical intervention of the same vertebral level was defined as revision surgery. A Spine Surgical Invasiveness Index (SSII)\u0026thinsp;\u0026gt;\u0026thinsp;10 was used to define complex surgery.\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e Patients lacking a pre-operative CT or MRI of the lumbar spine obtained at our facility within six months of surgery, poor image quality, pre-operative MRI or CT acquired at any outside facilities, clinical evidence of L1 or L2 nerve root compression, a history of previous surgical treatment to or through the psoas muscle, and coronal deformity greater than 20 degrees were excluded as mentioned in our previous study.\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e\n\u003ch2\u003eData Collection\u003c/h2\u003e\n\u003cp\u003eElectronic medical records were utilized retrospectively to obtain demographic data including age, gender, BMI, American Anesthesiologists\u0026rsquo; Society (ASA) class, comorbidities, indication for revision operation, baseline ambulation status, and presence of neurologic deficits. BMI\u0026thinsp;\u0026ge;\u0026thinsp;30.0 kg/m\u003csup\u003e2\u003c/sup\u003e was used to define obesity. Intraoperative data was acquired which included estimated blood loss (EBL) and operative time defined as time of incision to post-operative dressing placement. SSII, a verified method of evaluation and comparison regarding spine surgery complexity was used, with a range of 0\u0026ndash;48, which accounts for surgical approaches and the amount of decompressed, fused, and instrumented vertebral levels. \u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e In regard to the included surgical population with revision surgeries, only the additional levels of fusion, instrumentation, or decompression were accounted for the SSII calculation as previously stated.\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e Each patients\u0026rsquo; primary surgery SSII score was also obtained.\u003c/p\u003e\n\u003ch2\u003eAssessment Of Sarcopenia\u003c/h2\u003e\n\u003cp\u003ePMI was used to analyze sarcopenia, which was calculated by measuring the total cross-sectional area (CSA) of the bilateral psoas muscles at the L3 vertebral body using the pre-operative T1 weighted MRI or CT normalized to body height\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e (mm\u003csup\u003e2\u003c/sup\u003e/m\u003csup\u003e2\u003c/sup\u003e). The total CSA was measured using OsiriX DICOM Viewer software (Version 11.0, Bernex, Switzerland) by manual outlining the bilateral psoas muscles at the first axial cut, done in the craniocaudal direction where both transverse processes are visible at the L3 level. \u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e,\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e All of the images were obtained at a single institution with the same scanning protocols ensuring identical scanning thickness among all images analyzed. Three separate reviewers performed all measurements to improve interobserver reliability. Each measurement was acquired three times by all reviewers to improve intraobserver reliability. Intraclass correlation coefficient (ICC) was used to assess interobserver and intraobserver reliabilities, where an ICC above 0.90 signifies excellent agreement, between 0.75 and 0.90 signifies good agreement, between 0.5 and 0.75 signifies moderate agreement, and below 0.5 signifies poor agreement.\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e Each of the mean values obtained by the three reviewers was divided by the square of patient height to calculate the PMI as previously described.\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e To minimize the risk of bias, all reviewers were blinded to their respective measurements as well as to patient demographics and outcomes. Sarcopenia was defined as PMI\u0026thinsp;\u0026lt;\u0026thinsp;500 mm\u003csup\u003e2\u003c/sup\u003e/m\u003csup\u003e2\u003c/sup\u003e for males and \u0026lt;\u0026thinsp;412 mm\u003csup\u003e2\u003c/sup\u003e/m\u003csup\u003e2\u003c/sup\u003e for females as previously defined.\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e\n\u003ch2\u003eOutcome Measures\u003c/h2\u003e\n\u003cp\u003eRetrospective analysis of electronic medical records were used to review all perioperative outcomes. The primary outcome measures were perioperative AEs which included post-operative anemia that required transfusion, cardiac complication (cardiac arrest and myocardial infarction), sepsis, wound complication (wound dehiscence and deep wound infection), acute kidney injury (AKI), delirium, intra-operative dural tear, pneumonia, urinary tract infection (UTI), urinary retention, epidural hematoma, and deep vein thrombosis (DVT). The secondary outcome measures used were 30-day readmission rates, 30-day re-operation rates, in-hospital mortality rates, discharge disposition (home vs facility) and post-operative hospital length of stay (LOS). The number of days from surgery (or the last surgery if staged procedure) to discharge to either home or facility was used to defined postoperative LOS.\u003c/p\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eStatistical Analysis\u003c/h2\u003e \u003cp\u003eSPSS statistical software (Version 25.0; SPSS, Inc, Chicago, IL) was utilized to perform data analysis. The Chi-Square or Fisher\u0026rsquo;s exact test and continuous data was used to analyze categorical data and was further analyzed using Two-tailed student \u003cem\u003et-\u003c/em\u003etest. Continuous variables with non-normal distribution was analyzed using the Mann-Whitney U test. Statistical significance was set to p-value\u0026thinsp;\u0026lt;\u0026thinsp;0.05. The odds ratio (OR) with 95% confidence interval (CI) was calculated for comparing perioperative outcomes. Post hoc power analysis with a two-tailed alpha of 0.05 was performed between obese and non-obese groups to evaluate the power of detecting differences between patients experiencing any perioperative. A multivariable logistic regression model was used to determine the effects of sarcopenia, obesity, age, and gender on the likelihood of the occurrence of any AE.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eIn total, there were 166 patients that met the inclusion criteria and 52 were removed based on the exclusion criteria. Final analysis included 114 patients (mean age 60.1\u0026thinsp;\u0026plusmn;\u0026thinsp;15.4 years, 45 males, 69 females). The overall mean PMI was 495.0\u0026thinsp;\u0026plusmn;\u0026thinsp;182.9 mm\u003csup\u003e2\u003c/sup\u003e/m\u003csup\u003e2\u003c/sup\u003e. Interobserver and intraobserver reliabilities were considered excellent with ICC of 0.908 (95% CI 0.862\u0026ndash;0.944) and 0.962 (95% CI 0.928\u0026ndash;0.975), respectively. 54 patients were in the obese cohort and 60 patients in the non-obese cohort. The obese patients had a higher BMI and PMI compared to non-obese patients; otherwise, there were no significant differences in baseline demographics, comorbidities, presence of motor/sensory deficits, ambulatory status, indication for reoperation, or SSII between the two groups (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). No significant difference between the perioperative outcomes was found among the obese and non-obese patients (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDemographics and Characteristics of the Study Population\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eObese (n\u0026thinsp;=\u0026thinsp;54)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNon-obese (n\u0026thinsp;=\u0026thinsp;60)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eBMI (kg/m\u003csup\u003e2\u003c/sup\u003e), mean \u0026plusmn; SD (range)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e36.2 \u0026plusmn; 5.4 (30.0\u0026ndash;51.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e25.8 \u0026plusmn; 3.0 (16.0\u0026ndash;29.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eMale, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e25 (46.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e20 (33.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.159\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eAge (y), mean \u0026plusmn; SD (range)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e61.4 \u0026plusmn; 12.0 (20\u0026ndash;77)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e62.1 \u0026plusmn; 13.3 (25\u0026ndash;80)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.768\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eASA Class, mean \u0026plusmn; SD (range)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.78 \u0026plusmn; 0.54 (2\u0026ndash;4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.57 \u0026plusmn; 0.65 (1\u0026ndash;4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.060\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003ePMI (mm\u003csup\u003e2\u003c/sup\u003e/m\u003csup\u003e2\u003c/sup\u003e), mean \u0026plusmn; SD (range)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e545.3 \u0026plusmn; 174.4 (190.0\u0026ndash;941.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e449.6 \u0026plusmn; 179.8 (152.2\u0026ndash;940.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.004*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eComorbidities, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11 (20.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e10 (16.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.611\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSmoking\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7 (13.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7 (11.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.834\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCardiac (CHF, CAD, Atrial fibrillation)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11 (20.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e14 (23.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.704\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCKD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7 (13.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e9 (15.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.757\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCOPD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e19 (35.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e15 (25.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.234\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCVA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (1.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 (1.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.936\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePVD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (3.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 (1.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.497\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCancer\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4 (7.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2 (3.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.332\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eNo pre-operative motor deficits, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e41 (75.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e39 (65.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.204\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eNo pre-operative sensory deficits, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e35 (64.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e30 (50.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.110\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eAmbulatory status, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAmbulate without assistive device\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e16 (29.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e20 (33.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.674\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAmbulate with assistive device\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e30 (55.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e23 (38.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.066\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWheelchair bound\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8 (14.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7 (11.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.617\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNot recorded\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4 (7.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6 (10.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.624\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eIndication for reoperation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSpinal stenosis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e22 (40.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e29 (48.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.418\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDisc disease\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13 (24.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e16 (26.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.749\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSpondylolisthesis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14 (25.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e14 (23.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.749\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTrauma\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3 (5.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2 (3.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.562\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDeformity\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e25 (46.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e27 (45.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.889\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAdjacent segment disease\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e22 (40.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e24 (40.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.936\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePseudarthrosis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e27 (50.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e30 (50.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHNP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3 (5.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3 (5.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.897\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eInfection\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (3.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 (1.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.497\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eSSII of primary surgery, mean \u0026plusmn; SD (range)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11.9 \u0026plusmn; 6.3 (3\u0026ndash;32)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e13.9 \u0026plusmn; 5.9 (3\u0026ndash;32)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.067\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eSSII of revision surgery, mean \u0026plusmn; SD (range)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e25.6 \u0026plusmn; 13.7 (11\u0026ndash;48)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e25.8 \u0026plusmn; 11.3 (11\u0026ndash;48)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.943\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cp\u003e\u003cem\u003e*Statistically significant values\u003c/em\u003e\u003c/p\u003e \u003cp\u003e\u003cem\u003ePMI, psoas muscle index; ASA, American Society of Anesthesiologists; BMI, body mass index; DM, diabetes mellitus; CHF, congestive heart failure; CAD, coronary artery disease; CKD, chronic kidney disease; COPD, chronic obstructive pulmonary disease; CVA, cerebrovascular accident; PVD, peripheral vascular disease; HNP, herniated nucleus pulposus; SSII, spine surgical invasiveness index\u003c/em\u003e\u003csup\u003e\u003cem\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/em\u003e\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComparison of Perioperative Outcomes\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eObese (N\u0026thinsp;=\u0026thinsp;54)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNon-obese (n\u0026thinsp;=\u0026thinsp;60)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e Value\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eOR (95% CI)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eOperative time (minutes), mean \u0026plusmn; SD (range)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e387.1 \u0026plusmn; 224.3 (108\u0026ndash;1160)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e372.2 \u0026plusmn; 172.7 (122\u0026ndash;937)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.693\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eEBL (mL), mean \u0026plusmn; SD (range)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1235.5 \u0026plusmn; 1792.4 (75-12321)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e856.2 \u0026plusmn; 744.0 (50-4600)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.152\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eEBL\u0026thinsp;\u0026gt;\u0026thinsp;1 L, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e22 (40.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e19 (31.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.490\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.29 (0.63\u0026ndash;2.63)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eIntraoperative pRBC transfusion units, mean \u0026plusmn; SD (range)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.2 \u0026plusmn; 2.6 (0\u0026ndash;15)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.7 \u0026plusmn; 1.6 (0\u0026ndash;8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.238\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003ePost-operative LOS (days), mean \u0026plusmn; SD (range)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7.1 \u0026plusmn; 5.6 (2\u0026ndash;36)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6.3 \u0026plusmn; 4.0 (1\u0026ndash;19)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.375\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eDischarge Disposition, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHome\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e20 (37.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e19 (31.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.547\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.27 (0.59\u0026ndash;2.76)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFacility\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e34 (63.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e41 (68.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.547\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.79 (0.36\u0026ndash;1.71)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e30-day Reoperation, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4 (7.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5 (8.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.855\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.88 (0.22\u0026ndash;3.46)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e30-day Readmission, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4 (7.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6 (10.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.626\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.72 (0.19\u0026ndash;2.70)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eIn-hospital mortality, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 (1.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.539\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.36 (0.01\u0026ndash;9.12)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003ePerioperative Adverse Events, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAny adverse events\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e22 (40.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e33 (55.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.130\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.56 (0.27\u0026ndash;1.18)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePost-op anemia requiring transfusion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8 (14.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e18 (30.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.058\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.41 (0.16\u0026ndash;1.03)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCardiac (cardiac arrest, MI)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (1.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2 (3.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.487\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.55 (0.05\u0026ndash;6.21)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSepsis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 (1.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.539\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.36 (0.01\u0026ndash;9.12)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWound complication (dehiscence, infection)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4 (7.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7 (11.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.763\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.61 (0.17\u0026ndash;2.20)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDelirium\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (3.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8 (13.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.089\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.25 (0.05\u0026ndash;1.23)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIntra-op dural tear\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (1.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3 (5.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.387\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.36 (0.04\u0026ndash;3.55)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAKI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5 (9.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7 (11.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.676\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.77 (0.23\u0026ndash;2.59)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePneumonia\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3 (5.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6 (10.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.386\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.53 (0.13\u0026ndash;2.23)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eUTI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (3.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e9 (15.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.059\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.21 (0.04\u0026ndash;1.06)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eUrinary retention\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4 (7.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3 (5.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.595\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.52 (0.32\u0026ndash;7.12)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEpidural hematoma\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (3.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.262\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5.76 (0.27\u0026ndash;122.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDVT\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4 (7.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6 (10.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.626\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.72 (0.19\u0026ndash;2.70)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNerve injury or paralysis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (3.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.262\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5.76 (0.27\u0026ndash;122.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"6\" nameend=\"c6\" namest=\"c1\"\u003e \u003cp\u003e\u003cem\u003eOR, odds ratio; EBL, estimated blood loss; SD, standard deviation; CI, confidence interval; pRBC, packed red blood cells; LOS, length of stay; MI, myocardial infarction; AKI, acute kidney injury; UTI, urinary tract infection; DVT, deep vein thrombosis\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eUsing the prior defined definition of sarcopenia as PMI\u0026thinsp;\u0026lt;\u0026thinsp;500 mm\u003csup\u003e2\u003c/sup\u003e/m\u003csup\u003e2\u003c/sup\u003e for males and \u0026lt;\u0026thinsp;412 mm\u003csup\u003e2\u003c/sup\u003e/m\u003csup\u003e2\u003c/sup\u003e for females, 15 patients were considered obese and sarcopenic and 34 patients were considered non-obese and sarcopenic.\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e No significant difference in perioperative outcomes was found between these patients (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e3\u003c/span\u003e). 39 patients were considered obese and non-sarcopenic and 26 patients were considered non-obese and non-sarcopenic. No significant difference in perioperative outcomes was found between these patients (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComparison of Perioperative Outcomes among Sarcopenic Patients\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eObese\u0026thinsp;+\u0026thinsp;Sarcopenic (N\u0026thinsp;=\u0026thinsp;15)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNon-obese\u0026thinsp;+\u0026thinsp;Sarcopenic (n\u0026thinsp;=\u0026thinsp;34)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e Value\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eOR (95% CI)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eOperative time (minutes), mean \u0026plusmn; SD (range)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e387.9 \u0026plusmn; 209.4 (186\u0026ndash;993)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e408.9 \u0026plusmn; 165.4 (198\u0026ndash;937)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.734\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eEBL (mL), mean \u0026plusmn; SD (range)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1118.3 \u0026plusmn; 1071.8 (150\u0026ndash;3500)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e926.2 \u0026plusmn; 605.6 (50-2400)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.524\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eEBL\u0026thinsp;\u0026gt;\u0026thinsp;1 L, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7 (46.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e14 (41.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.822\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.13 (0.38\u0026ndash;3.38)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eIntraoperative pRBC transfusion units, mean \u0026plusmn; SD (range)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.2 \u0026plusmn; 2.2 (0\u0026ndash;7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.8 \u0026plusmn; 1.4 (0\u0026ndash;6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.278\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003ePost-operative LOS (days), mean \u0026plusmn; SD (range)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8.1 \u0026plusmn; 3.8 (3\u0026ndash;14)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7.2 \u0026plusmn; 4.4 (2\u0026ndash;19)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.460\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eDischarge Disposition, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHome\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3 (20.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4 (11.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.453\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.88 (0.36\u0026ndash;9.66)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFacility\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12 (80.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e30 (88.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.453\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.53 (0.10\u0026ndash;2.75)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e30-day Reoperation, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3 (20.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4 (11.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.453\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.88 (0.36\u0026ndash;9.66)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e30-day Readmission, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3 (20.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5 (14.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.645\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.45 (0.30\u0026ndash;7.05)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eIn-hospital mortality, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 (2.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.844\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.72 (0.03\u0026ndash;18.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003ePerioperative Adverse Events, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAny adverse events\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10 (66.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e26 (76.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.476\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.62 (0.16\u0026ndash;2.34)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePost-op anemia requiring transfusion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5 (33.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e15 (44.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.481\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.63 (0.18\u0026ndash;2.25)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCardiac (cardiac arrest, MI)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (6.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 (2.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.554\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2.36 (0.14\u0026ndash;40.4)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSepsis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 (2.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.844\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.72 (0.03\u0026ndash;18.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWound complication (dehiscence, infection)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3 (20.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6 (17.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.845\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.17 (0.25\u0026ndash;5.45)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDelirium\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (13.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7 (20.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.549\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.59 (0.11\u0026ndash;3.26)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIntra-op dural tear\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (6.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2 (5.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.916\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.14 (0.10\u0026ndash;13.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAKI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3 (20.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e9 (26.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.628\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.69 (0.16\u0026ndash;3.04)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePneumonia\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (6.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6 (17.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.330\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.33 (0.04\u0026ndash;3.05)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eUTI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (13.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7 (20.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.549\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.59 (0.11\u0026ndash;3.26)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eUrinary retention\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (13.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3 (8.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.633\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.59 (0.24\u0026ndash;10.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEpidural hematoma\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (6.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.237\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e7.14 (0.27\u0026ndash;185.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDVT\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3 (20.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5 (14.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.645\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.45 (0.30\u0026ndash;7.05)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNerve injury or paralysis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (6.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.237\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e7.14 (0.27\u0026ndash;185.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"6\" nameend=\"c6\" namest=\"c1\"\u003e \u003cp\u003e\u003cem\u003eOR, odds ratio; EBL, estimated blood loss; SD, standard deviation; CI, confidence interval; LOS, length of stay; MI, myocardial infarction; AKI, acute kidney injury; UTI, urinary tract infection; DVT, deep vein thrombosis\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComparison of Perioperative Outcomes Among Non-Sarcopenic Patients\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eObese\u0026thinsp;+\u0026thinsp;Non-Sarcopenic (N\u0026thinsp;=\u0026thinsp;39)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNon-Obese\u0026thinsp;+\u0026thinsp;Non-Sarcopenic (N\u0026thinsp;=\u0026thinsp;26)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e Value\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eOR (95% CI)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eOperative time (minutes), mean \u0026plusmn; SD (range)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e386.8 \u0026plusmn; 232.4 (108\u0026ndash;1160)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e324.1 \u0026plusmn; 173.3 (122\u0026ndash;847)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.218\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eEBL (mL), mean \u0026plusmn; SD (range)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1280.6 \u0026plusmn; 2012.5 (75-12321)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e764.7 \u0026plusmn; 898.3 (50-4600)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.166\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eEBL\u0026thinsp;\u0026gt;\u0026thinsp;1 L, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e15 (38.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5 (19.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.228\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2.00 (0.65\u0026ndash;6.17)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eIntraoperative pRBC transfusion units, mean \u0026plusmn; SD (range)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.2 \u0026plusmn; 2.8 (0\u0026ndash;15)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.6 \u0026plusmn; 1.8 (0\u0026ndash;8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.135\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003ePost-operative LOS (days), mean \u0026plusmn; SD (range)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6.8 \u0026plusmn; 6.1 (2\u0026ndash;36)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5.2 \u0026plusmn; 3.1 (1\u0026ndash;13)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.176\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eDischarge Disposition, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHome\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e17 (43.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e15 (57.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.267\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.57 (0.21\u0026ndash;1.55)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFacility\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e22 (56.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e11 (42.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.267\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.76 (0.65\u0026ndash;4.81)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e30-day Reoperation, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (2.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 (3.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.771\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.66 (0.04-11.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e30-day Readmission, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (2.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 (3.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.771\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.66 (0.04-11.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eIn-hospital mortality, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.843\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.67 (0.01\u0026ndash;34.9)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003ePerioperative Adverse Events, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAny adverse events\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12 (30.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7 (26.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.739\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.21 (0.40\u0026ndash;3.63)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePost-op anemia requiring transfusion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3 (7.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3 (11.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.602\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.64 (0.12\u0026ndash;3.44)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCardiac (cardiac arrest, MI)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 (3.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.353\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.22 (0.01\u0026ndash;5.49)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSepsis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.843\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.67 (0.01\u0026ndash;34.9)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWound complication (dehiscence, infection)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (2.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 (3.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.771\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.66 (0.04-11.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDelirium\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 (3.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.353\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.22 (0.01\u0026ndash;5.49)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIntra-op dural tear\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 (3.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.353\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.22 (0.01\u0026ndash;5.49)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAKI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4 (10.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.208\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e6.72 (0.35\u0026ndash;130.3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePneumonia\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (5.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.421\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e3.53 (0.16\u0026ndash;76.6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eUTI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.843\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.67 (0.01\u0026ndash;34.9)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eUrinary retention\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (5.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.421\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e3.53 (0.16\u0026ndash;76.6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEpidural hematoma\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (2.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.661\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2.06 (0.08\u0026ndash;52.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDVT\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (2.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 (3.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.771\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.66 (0.04-11.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNerve injury or paralysis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (2.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.661\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2.06 (0.08\u0026ndash;52.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"6\" nameend=\"c6\" namest=\"c1\"\u003e \u003cp\u003e\u003cem\u003eOR, odds ratio; EBL, estimated blood loss; SD, standard deviation; CI, confidence interval; LOS, length of stay; MI, myocardial infarction; AKI, acute kidney injury; UTI, urinary tract infection; DVT, deep vein thrombosis\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe multivariable logistic regression model was statistically significant, χ\u003csup\u003e2\u003c/sup\u003e(4)\u0026thinsp;=\u0026thinsp;28.572, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.0005. 72.8% of the cases were correctly classified by the model, which also explained 29.6% (Nagelkerke R\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e) of the variance in any AE. The model revealed that sarcopenic individuals had a significantly higher likelihood for an AE than non-sarcopenic individuals (OR: 7.53, 95% CI: 3.05\u0026ndash;18.60). Obesity, age, and gender did not have a significant effect in predicting AEs (Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). The post hoc power analysis between the obese and non-obese groups calculated a 95.2% power of detecting differences between patients experiencing any perioperative AEs.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMultivariable Logistic Regression Model to Assess Effects on Adverse Events\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eβ\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSE\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e Value\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eAdjusted OR (95% CI)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSarcopenia\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.019\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.461\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e7.53 (3.05\u0026ndash;18.6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eObesity\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.040\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.452\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.929\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.04 (0.43\u0026ndash;2.52)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.033\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.018\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.065\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.03 (1.00-1.07)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGender\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-0.066\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.444\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.882\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.94 (0.39\u0026ndash;2.24)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cp\u003e\u003cem\u003e*Statistically significant values\u003c/em\u003e\u003c/p\u003e \u003cp\u003e\u003cem\u003eSE, standard error; OR, odds ratio; CI, confidence interval\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn this study, the use of BMI as a predictor of perioperative AEs among patients undergoing complex thoracolumbar spine surgery was investigated. The multivariable logistic regression model confirmed that sarcopenic individuals were at a significantly higher likelihood to experience AE compared to non-sarcopenic individuals; however, there were no associations between BMI and perioperative AEs, 30-day readmission rates, 30-day re-operation rates, rate of discharge to a facility, or post-operative LOS among patients undergoing complex revision thoracolumbar spine surgery.\u003c/p\u003e \u003cp\u003eThe relationship between obesity and perioperative AEs has been an area of debate over the past decade. Various studies have shown a significantly higher risk of AEs among obese patients after thoracolumbar surgery.\u003csup\u003e\u003cspan additionalcitationids=\"CR18 CR19 CR20\" citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e The most recent study by Passias et al. determined that obese patients with a prior bariatric surgery had a significantly lower complication rate after thoracolumbar spine surgery compared with obese patients that did not undergo bariatric surgery.\u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e Our findings contradict these series of studies as our analysis demonstrated no significant difference in post-operative AEs between obese and non-obese patients. There are likely multiple reasons that our study had different results. First, our study performed a multivariable analysis with sarcopenia, measured by PMI, which demonstrated a significantly higher association with post-operative AEs. None of the prior studies that investigated the association between obesity and AEs included sarcopenia as a potential confounding variable. Second, our patient cohort consisted solely of complex revision cases, which is a particularly unique population with high complication rates at baseline. From our study analysis, it may be speculated that amongst these complex patients, pre-operative sarcopenia, and the associated debility and frailty, is a much better predictor for post-operative complications compared with the risks associated with obesity. Furthermore, studies have shown that although bariatric surgery is effective at lowering the BMI, this procedure may also induce sarcopenia post-operatively.\u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e,\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e Thus, with the known risks of sarcopenia shown within our study, it may be inadvisable to recommend bariatric surgery to improve BMI prior to undergoing complex revision thoracolumbar spine surgery.\u003c/p\u003e \u003cp\u003eA particularly important process among patients undergoing complex revision surgeries known to have high perioperative complications is preoperative risk stratification. Our previous study by Hirase et al. identified sarcopenia measured by PMI as a predictor of perioperative AEs among patients undergoing complex revision thoracolumbar spine surgery.\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e Our multivariable analysis within this study confirmed these findings and also demonstrated that obesity is not associated with perioperative AEs within this patient population. This combination of findings will specifically assist spine surgeons during pre-operative counseling and evaluation on two fronts. First, pre-operative optimization and overall conditioning to increase PMI among sarcopenic patients may be beneficial to preventing post-operative AE. Second, obese patients may not benefit from aggressive weight loss prior to these surgeries, particularly, as studies have shown that improper weight loss methods may lead to sarcopenia.\u003csup\u003e\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e,\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eOur study has several limitations. Data accuracy is contingent on charting accuracy due to the retrospective nature of the study and may be susceptible to certain selection bias. Our results obtained from a single-center data may not be completely reflective of outcomes from other institutions due to variations in surgical technique or management. Our study also consisted of a relatively small patient cohort that may have led to underpowering to detect certain associations; however, our post hoc power analysis demonstrated that the absence of observed difference is unlikely due to lack of power. Furthermore, there may have been small discrepancies in inter-scan agreement between CT and MRI scans used to obtain the PMI; however, this is a previously established method with studies showing good inter-scan reliability with an ICC of 0.821.\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e,\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e Thus, to increase the power of the study, patients were included if they received either a CT or an MRI pre-operatively. Furthermore, although this study demonstrates that obesity is not a predictor of post-operative AEs within this surgical population, we cannot directly conclude that weight loss will not be beneficial in preventing post-operative AEs. Therefore, further studies that investigate the external validity of this study may be beneficial prior to application in practice.\u003c/p\u003e \u003cp\u003eIn spite of the aformentioned limitations, to the best of our knowledge, this is the largest study examining the relationship between obesity and perioperative outcomes among patients receiving complex revision thoracolumbar spine surgery. This study will serve to assist spine surgeons with additional information during pre-operative counseling and evaluation regarding risks and benefits associated with sarcopenia and obesity. For patients undergoing complex revision thoracolumbar spine surgery, our findings may suggest that the benefits of weight loss among obese patients may not outweigh the risk of inducing sarcopenia prior to the operation.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eObesity is not associated with perioperative AEs, 30-day readmission rates, 30-day re-operation rates, rate of discharge to a facility, or post-operative length of stay (LOS) among patients undergoing complex revision thoracolumbar spine surgery.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eAEs\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eadverse events; PMI\u0026thinsp;=\u0026thinsp;psoas muscle index; LOS\u0026thinsp;=\u0026thinsp;length of stay; BMI\u0026thinsp;=\u0026thinsp;body mass index; SSII\u0026thinsp;=\u0026thinsp;spine surgical invasiveness index; ASA\u0026thinsp;=\u0026thinsp;American Anesthesiologists\u0026rsquo; Society; EMR\u0026thinsp;=\u0026thinsp;electronic medical records; EBL\u0026thinsp;=\u0026thinsp;estimated blood loss; CSA\u0026thinsp;=\u0026thinsp;cross-sectional area; ICC\u0026thinsp;=\u0026thinsp;intraclass correlation coefficient; AKI\u0026thinsp;=\u0026thinsp;acute kidney injury; UTI\u0026thinsp;=\u0026thinsp;urinary tract infection; DVT\u0026thinsp;=\u0026thinsp;deep vein thrombosis; OR\u0026thinsp;=\u0026thinsp;odds ratio; CI\u0026thinsp;=\u0026thinsp;confidence interval\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate:\u003c/strong\u003e The study protocol was approved through the Houston Methodist Hospital institutional review board on April 13, 2020 (PRO00024733) with a waiver for informed consent attributed to the study\u0026rsquo;s retrospective observational nature.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication:\u003c/strong\u003e Written informed consent for publication of their clinical details and/or clinical images was obtained from the patient/parent/guardian/ relative of the patient. A copy of the consent form is available for review by the Editor of this journal.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and material:\u003c/strong\u003e Available upon request to corresponding author\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests:\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTakashi Hirase, Jeremiah Ling, Varan Haghshenas, Richard Fuld III, David Dong, and B Christoph Meyer declare no potential conflicts of interest with respect to research, authorship, and/or publication of this article.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eRex AW Marco has the following disclosures:\u003c/p\u003e\n\u003cp\u003eDePuy, A Johnson \u0026amp; Johnson Company: Paid presenter or speaker; Globus Medical: Paid presenter or speaker; Musculoskeletal Tumor Society: Board or committee member; Stryker: Paid presenter or speaker; Synaptive Medical: Paid presenter or speaker\u003c/p\u003e\n\u003cp\u003eDarrell S Hanson has the following disclosures:\u003c/p\u003e\n\u003cp\u003eDePuy, A Johnson \u0026amp; Johnson Company: IP royalties; Paid consultant; Paid presenter or speaker; Medtronic Sofamor Danek: Paid consultant; Paid presenter or speaker\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e: None\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor\u0026rsquo;s Contributions:\u0026nbsp;\u003c/strong\u003eAll authors made substantial contributions to the conception and design of work and provided final approval of the version to be published. Specific additional individual contribution includes: Takashi Hirase: Interpretation and analysis of data for the work. Drafted the introduction, the overall work outline, and made critical final revisions. Jeremiah Ling: Lead the acquisition of data and drafted the results section. Varan Haghshenas: Drafted a portion of the discussion section and made critical final revisions. Richard Fuld III: Assisted in the acquisition of data and drafted the results section. David Dong: Assisted in the acquisition of data and drafted the results section. Darrell Hanson: Senior surgeon with substantial contribution to design of work and made critical final revisions and approval of the version to be published. B Christoph Meyer: Senior surgeon with substantial contribution to design of work and made critical final revisions and approval of the version to be published. Rex AW Marco: Senior surgeon with substantial contribution to design of work and made critical final revisions and approval of the version to be published\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements:\u0026nbsp;\u003c/strong\u003eTakashi Hirase was supported by a Burroughs Wellcome Fund Physician Scientist Institutional Award to the Texas A\u0026amp;M University Academy of Physician Scientists\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eFlegal KM, Carroll MD, Kuczmarski RJ, \u0026amp; Johnson CL. Overweight and obesity in the United States: prevalence and trends, 1960\u0026ndash;1994. Int J Obes Relat Metab Disord. 1998;22(1):39\u0026ndash;47.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eClinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults\u0026ndash;The Evidence Report. National Institutes of Health. Obes Res. 1998;6 Suppl 2:51S-209S.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePurnell, J. Q. Definitions, Classification, and Epidemiology of Obesity. In: K. R. Feingold Anawalt B, Boyce A, Chrousos G, de Herder WW, Dhatariya K, Dungan K, Grossman A, Hershman JM, et. al. 2018. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://www.endotext.org\u003c/span\u003e\u003c/span\u003e. Accessed Oct 2020.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePark, P., Upadhyaya, C., Garton, H. J., \u0026amp; Foley, K. T. The impact of minimally invasive spine surgery on perioperative complications in overweight or obese patients. Neurosurgery. 2008;62(3):693\u0026ndash;699.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCao, J., Kong, L., Meng, F., Zhang, Y., \u0026amp; Shen, Y. Impact of obesity on lumbar spinal surgery outcomes. J Clin Neurosci. 2016;28:1\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eManson, N. A., Green, A. J., \u0026amp; Abraham, E. P. Elevated Patient Body Mass Index Does Not Negatively Affect Self-Reported Outcomes of Thoracolumbar Surgery: Results of a Comparative Observational Study with Minimum 1-Year Follow-Up. Global Spine J. 2016;6(2):108\u0026ndash;117.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShamji, M. F., Parker, S., Cook, C., Pietrobon, R., Brown, C., \u0026amp; Isaacs, R. E. Impact of body habitus on perioperative morbidity associated with fusion of the thoracolumbar and lumbar spine. Neurosurger\u003cem\u003ey.\u003c/em\u003e 2009;65(3):490\u0026ndash;498.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYadla S, Malone J, Campbell PG, Maltenfort MG, Harrop JS, Sharan AD, et al. Obesity and spine surgery: reassessment based on a prospective evaluation of perioperative complications in elective degenerative thoracolumbar procedures. Spine J. 2010;10(7):581\u0026ndash;587.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVarshneya K, Pangal DJ, Stienen MN, Ho AL, Fatemi P, Medress ZA, et al. Postoperative Complication Burden, Revision Risk, and Health Care Use in Obese Patients Undergoing Primary Adult Thoracolumbar Deformity Surgery. Global Spine J. 2021;11(3):345\u0026ndash;350.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKim SS, Michelsen CB. Revision Surgery for failed back surgery syndrome. Spine (Phila Pa 1976). 1992;17(8):957\u0026ndash;60.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFritsch EW, Heisel J, Rupp S. The failed back surgery syndrome: reasons, intraoperative findings, and long-term results: a report of 182 operative treatments. Spine (Phila Pa 1976). 1996;21(5):626\u0026ndash;33.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSansur CA, Smith JS, Coe JD, Glassman SD, Berven SH, Polly DW Jr, et al. Scoliosis research society morbidity and mortality of adult scoliosis surgery. Spine (Phila Pa 1976). 2011;36(9):E593\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCamino Willhuber G, Elizondo C, Slullitel P. Analysis of Postoperative Complications in Spinal Surgery, Hospital Length of Stay, and Unplanned Readmission: Application of Dindo-Clavien Classification to Spine Surgery. Global Spine J. 2019;9(3):279\u0026ndash;86.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHirase T, Haghshenas V, Bratescu R, Dong D, Kuo PH, Rashid A, et al. Sarcopenia Predicts Perioperative Adverse Events Following Complex Revision Surgery for the Thoracolumbar Spine. Spine J. 2021 Jun;21(6):1001\u0026ndash;1009.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMoskven E, Bourassa-Moreau E, Charest-Morin R, Flexman A, Street J. The impact of frailty and sarcopenia on postoperative outcomes in adult spine surgery. A systematic review of the literature. Spine J. 2018; 18(12):2354\u0026ndash;69.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKoo TK, Li MY. A Guideline of Selecting and Reporting Intraclass Correlation Coefficients for Reliability Research. J Chiropr Med. 2016;15(2):155\u0026ndash;63.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKnutsson BB, Micha\u0026euml;lsson K, Sand\u0026eacute;n B. Obesity is associated with inferior results after surgery for lumbar spinal stenosis: a study of 2633 patients from the Swedish spine register. Spine (Phila Pa 1976). 2013;38(5):435\u0026ndash;441\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMarquez-Lara A, Nandyala SV, Sankaranarayanan S, Noureldin M, Singh K. Body mass index as a predictor of complications and mortality after lumbar spine surgery. Spine (Phila Pa 1976). 2014;39(10):798\u0026ndash;804\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBuerba RA, Fu MC, Gruskay JA, Long WD 3rd, Grauer JN. Obese class III patients at significantly greater risk of multiple complications after lumbar surgery: an analysis of 10,387 patients in the ACS NSQIP database. Spine J. 2013;14(9):2008\u0026ndash;2018\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChristou NV, Sampalis JS, Liberman M, Look D, Auger S, McLean AP, MacLean LD. Surgery decreases long-term mortality, morbidity, and health care use in morbidly obese patients. Ann Surg. 2004;240(3):416-23-4\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePassias PG, Horn SR, Vasquez-Montes D, Shepard N, Segreto FA, Bortz CA, et al. Prior bariatric surgery lowers complication rates following spine surgery in obese patients. Acta Neurochir (Wien). 2018;160(12):2459\u0026ndash;2465.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePekař M, Pekařov\u0026aacute; A, Bužga M, Hol\u0026eacute;czy P, Soltes M. The risk of sarcopenia 24 months after bariatric surgery - assessment by dual energy X-ray absorptiometry (DEXA): a prospective study. Wideochir Inne Tech Maloinwazyjne. 2020 Dec;15(4):583\u0026ndash;587.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVoican CS, Lebrun A, Maitre S, Lainas P, Lamouri K, Njike-Nakseu M, et al. Predictive score of sarcopenia occurrence one year after bariatric surgery in severely obese patients. PLoS One. 2018;13(5):e0197248.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMiller SL, Wolfe RR. The danger of weight loss in the elderly. J Nutr Health Aging. 2008;12(7):487\u0026ndash;91.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTournadre A, Vial G, Capel F, Soubrier M, Boirie Y. Sarcopenia. Joint Bone Spine. 2019;86(3):309\u0026ndash;314.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePark J, Gil JR, Shin Y, Won SE, Huh J, You MW, Park HJ, et al. Reliable and robust method for abdominal muscle mass quantification using CT/MRI: An explorative study in healthy subjects. PLoS One. 2019;14(9):e0222042.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-musculoskeletal-disorders","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bmsd","sideBox":"Learn more about [BMC Musculoskeletal Disorders](http://bmcmusculoskeletdisord.biomedcentral.com/)","snPcode":"","submissionUrl":"https://author-welcome.nature.com/12891","title":"BMC Musculoskeletal Disorders","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"obesity, revision thoracolumbar spine surgery, sarcopenia, complex, predictor.","lastPublishedDoi":"10.21203/rs.3.rs-789945/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-789945/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eStudy Design:\u003c/strong\u003e Retrospective cohort study\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eObjective\u003c/strong\u003e: This study sought to determine the relationship between obesity and perioperative adverse events (AEs) with patients undergoing complex revision thoracolumbar spine surgery while controlling for psoas muscle index (PMI) as a confounding variable.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eMethods: \u003c/strong\u003eBetween May 2016 and February 2020, a retrospective analysis of individuals undergoing complex revision surgery of the thoracolumbar spine was performed at a single institution. Obesity was defined as BMI ≥ 30.0 kg/m\u003csup\u003e2\u003c/sup\u003e. PMI \u0026lt; 500 mm\u003csup\u003e2\u003c/sup\u003e/m\u003csup\u003e2 \u003c/sup\u003efor males and \u0026lt; 412 mm\u003csup\u003e2\u003c/sup\u003e/m\u003csup\u003e2\u003c/sup\u003e for females were used to define sarcopenia. A Spine Surgical Invasiveness Index (SSII) \u0026gt; 10 was used to define complex revision surgery. A multivariable logistic regression model was used to ascertain the effects of sarcopenia, obesity, age, and gender on the likelihood of the occurrence of any AE.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e The study included 114 patients. 54 patients were in the obese cohort and 60 patients in the non-obese cohort.\u0026nbsp;There was not a significant difference in perioperative outcomes of both the obese and non-obese patients. Multivariable analysis demonstrated that sarcopenic individuals had a significantly higher likelihood for an AE than non-sarcopenic individuals (OR: 7.53, 95% CI: 3.05-18.60). Obesity did not have a significant effect in predicting AEs.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eConclusions:\u003c/strong\u003e Obesity is not associated with perioperative AEs, 30-day readmission rates, 30-day re-operation rates, rate of discharge to a facility, or post-operative length of stay (LOS) among patients undergoing complex revision thoracolumbar spine surgery.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eLevel of Evidence:\u003c/strong\u003e III\u003c/p\u003e","manuscriptTitle":"Obesity is Not Associated with Perioperative Adverse Events in Patients Undergoing Complex Revision Surgery for the Thoracolumbar Spine","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2021-09-01 14:50:27","doi":"10.21203/rs.3.rs-789945/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major revision","date":"2022-03-21T22:03:05+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2022-02-12T16:05:44+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"bc6415ab-d1cc-4f13-8108-c82e42ed13ec","date":"2022-02-12T15:38:15+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2022-01-17T01:42:20+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"333b756a-30fc-4ff4-becd-a2905bc1f8a2","date":"2022-01-12T01:04:08+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"8c52d03e-6fa4-4cdd-b55b-6893223965a9","date":"2021-12-16T22:06:29+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2021-09-01T00:23:04+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2021-09-01T00:03:33+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2021-08-31T09:20:45+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2021-08-31T09:18:33+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Musculoskeletal Disorders","date":"2021-08-07T20:37:33+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-musculoskeletal-disorders","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bmsd","sideBox":"Learn more about [BMC Musculoskeletal Disorders](http://bmcmusculoskeletdisord.biomedcentral.com/)","snPcode":"","submissionUrl":"https://author-welcome.nature.com/12891","title":"BMC Musculoskeletal Disorders","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"00ffbe4e-6fd7-410d-bf35-34d5a4289d7a","owner":[],"postedDate":"September 1st, 2021","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":6877883,"name":"Orthopedics"}],"tags":[],"updatedAt":"2022-06-01T20:44:12+00:00","versionOfRecord":[],"versionCreatedAt":"2021-09-01 14:50:27","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-789945","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-789945","identity":"rs-789945","version":["v1"]},"buildId":"ehx78VzkSd0WSzXnipQa-","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}