The Impact of Paraspinal Sarcopenia Compared to Generalized Sarcopenia on Conservative Treatment Outcomes in Degenerative Lumbar Spinal Stenosis

The Impact of Paraspinal Sarcopenia Compared to Generalized Sarcopenia on Conservative Treatment Outcomes in Degenerative Lumbar Spinal Stenosis | 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 The Impact of Paraspinal Sarcopenia Compared to Generalized Sarcopenia on Conservative Treatment Outcomes in Degenerative Lumbar Spinal Stenosis Jinwoo Jin, Seung Myung Wi This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5400496/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 07 Oct, 2025 Read the published version in Clinical Spine Surgery → Version 1 posted You are reading this latest preprint version Abstract Purpose To evaluate the concordance between assessment tools for generalized and paraspinal sarcopenia in patients with degenerative spinal stenosis, and to identify risk factors associated with conservative treatment failure and poor prognosis. Methods We retrospectively reviewed 101 patients with degenerative lumbar spinal stenosis who underwent MRI/whole-body DXA and at least three months of conservative treatment between 2013 and 2023. Patients were divided into two groups: 71 patients who continued with conservative treatment (Group A) and 30 patients who underwent surgery after conservative treatment failure (Group B). The decision to proceed with surgery was based on persistent or worsening symptoms despite comprehensive conservative management, and the surgical procedures performed included posterior decompressive laminectomy, with or without spinal fusion. Two independent reviewers assessed paraspinal and psoas muscle quality using axial T2 MRI. Paraspinal sarcopenia was determined by cross-sectional area (CSA) and the Goutalier classification of the paralumbar (PL) multifidus and erector spinae muscles. Generalized sarcopenia was assessed by normalized total psoas area (NTPA) and appendicular skeletal muscle mass (ASM) values by DXA. Patients were divided into two groups based on conservative treatment success or failure, and characteristics were compared using the Student t-test and chi-squared test. Logistic regression generated unadjusted odds ratios (OR) for conservative treatment failure. Spearman’s rank correlation coefficient (rho) was used to calculate the correlation between assessments of paraspinal and generalized sarcopenia. Results Patients who underwent surgery had a lower PL-CSA/BMI and higher fatty infiltration of PL muscles. No significant differences were found in generalized sarcopenia parameters between the groups. PL-CSA/BMI (OR: 0.983, p = 0.037) was independently associated with treatment failure. ASM/BMI had the highest correlation with PL-CSA/BMI (rho = 0.73, p < 0.001), though other correlations were significant but weaker. Conclusion Our study highlights the distinct role of paraspinal sarcopenia in degenerative lumbar spinal stenosis, showing a weak correlation with generalized sarcopenia. Paraspinal muscle health is crucial for predicting conservative treatment outcomes, emphasizing the need for specific diagnostic approaches. Future research should refine diagnostic criteria to improve patient management and outcomes. Figures Figure 1 Figure 2 Figure 3 Introduction Sarcopenia is a condition characterized by a progressive, age-related decline in skeletal muscle mass, strength, and function. The European Working Group on Sarcopenia in Older People (EWGSOP) has established sarcopenia as a progressive and widespread skeletal muscle disorder with a heightened risk of adverse outcomes [ 1 ]. In its second meeting (EGWSOP2), the definition of sarcopenia was refined to encompass diminished muscle strength, reduced muscle mass, and impaired physical performance. EGWSOP2 further delineated between acute and chronic presentations, as well as between idiopathic (age-related) and secondary sarcopenia. To identify and assess the severity of sarcopenia, EWGSOP2 recommends employing various screening methods, including grip strength assessments, evaluation of appendicular or central muscle mass, and performance tests such as the short physical performance battery (SPPB) [ 2 , 3 ]. Advances in imaging technologies have enhanced the ability to evaluate and diagnose sarcopenia, leading to a growing body of research on its impact, particularly within the context of spinal diseases. Currently, magnetic resonance imaging (MRI) and computed tomography (CT) are regarded as the gold standard techniques for assessing the quantity of paraspinal muscles. Dual energy X-ray absorptiometry (DXA) is regarded as the reference standard for assessing body muscle mass. DXA provides detailed measurements of both regional and total body muscle quantity, offering absolute values of lean mass (LM) as well as LM indices such as appendicular skeletal muscle mass (ASM) [ 3 – 6 ]. Lumbar spinal stenosis (LSS) arises from degenerative changes in the spine, causing narrowing of central canal, lateral recess, and/or neural foramen (Fig. 1 ). This condition, prevalent among the elderly, significantly impacts their quality of life and is a primary reason for spine surgery [ 7 ]. Research suggests that 33–50% of patients with mild to moderate LSS may experience positive outcomes without surgical intervention. Despite anecdotal concerns, rapid neurological decline is rare in these cases [ 8 ]. Surgical decompression is reserved for patients not responding to conservative treatments [ 9 ]. Recent studies have started to explore the relationship between paraspinal muscle sarcopenia and generalized sarcopenia, revealing a complex interplay between these conditions and spinal disorders. However, significant uncertainties remain, including the extent to which paraspinal muscle sarcopenia correlates with generalized sarcopenia, as well as how generalized sarcopenia influences the progression and treatment outcomes of spinal diseases. Furthermore, all studies on this topic have studied the impact of sarcopenia on postoperative outcomes, such as lumbar decompression surgery or lumbar spinal fusion, rather than the prognosis of conservative treatment [ 4 , 10 – 17 ]. The aim of this study is to investigate the concordance between various assessment tools for generalized and paraspinal sarcopenia among patients with degenerative spinal stenosis. Additionally, we seek to identify risk factors that could predict conservative treatment failure and poor clinical outcomes in this patient population. By addressing these objectives, this study aims to provide new insights into the diagnosis and management of sarcopenia in the context of spinal disease. Methods Upon obtaining approval from the Institutional Review Board (IRB) (Samsung Changwon Hospital of Sungkyunkwan University IRB; Approval No.2024-04-009), informed consent was waived by the IRB due to the retrospective nature of the study. We performed a retrospective review of 101 degenerative lumbar spinal stenosis patients with MRI and whole-body DXA who have undergone at least three months of conservative treatment at a single institution between 2013 and 2023. We excluded patients from the study if the time interval between MRI and DXA examination was more than 6 months or if the patient did not have 1-year follow-up data. Also, we excluded patients with peripheral neuropathy including diabetic neuropathy, myopathy, myelopathy, congenital anomalies such as spondylolysis or congenital spinal stenosis and cerebrovascular disease (defined as any history of stroke, transient ischemic attack, or other significant cerebrovascular events causing neurological deficits). Finally, patients with a history of previous lumbar spine surgery were excluded. The reporting of this study is in accordance with the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines. Muscle measurements were performed by two independent reviewers, a board-certified musculoskeletal radiologist and a spine surgeon with over 10 years of experience. They were blinded to the clinical history of the patients while analyzing axial T2 MRIs using our institution’s PACS system [INFINITT Healthcare Co., Ltd., Seoul, Republic of Korea]. Paraspinal Sarcopenia measurements Paraspinal sarcopenia was determined by assessing the cross-sectional area (CSA) and fatty infiltration of the paraspinal muscles (multifidus and erector spinae) using axial T2-weighted MRI images at the midpoint of the L4-L5 disc space level (Fig. 1 ). The CSA was measured by tracing the fascial boundary of these muscles on both sides. This regional measurement focuses on muscles directly involved in spinal support and function. All measured data were averaged. The measure was standardized by dividing by the height squared (CSA index; CSAI) and BMI (CSA/BMI) [ 12 , 14 – 16 , 18 ]. Fatty degeneration was evaluated using the Goutallier classification, which qualitatively grades the extent of intramuscular fat infiltration on a scale from 0 to 4. Goutallier classes were defined as follows: ‘0’ if there were no visible fat streaks in the muscle, ‘1’ if there were minimal fatty streaks in the muscle, ‘2’ if there was more muscle present than fat, ‘3’ if fat and muscle were present in equal quantity, and ‘4’ if more fat was present than muscle. (Fig. 1 ). Generalized Sarcopenia measurements Generalized sarcopenia was evaluated using whole-body dual-energy X-ray absorptiometry (DXA) scans (Horizon W; Hologic, MA), as recommended by the EWGSOP2 [ 3 ]. DXA provides a systemic assessment of muscle mass by measuring lean soft tissue mass across the entire body. Patients were scanned while wearing only hospital gowns to prevent artifacts, following our institution's standard protocol. The whole-body scans were manually analyzed using the Hologic QDR System software (version 13.6), following the manufacturer's guidelines for regions of interest (ROIs). We assessed both regional and total body muscle quantities. Standard ROIs included measurements of the arms, legs, trunk, and total body. Customized ROIs were also analyzed to focus on specific areas such as the total leg, upper leg, and lower leg, utilizing the software's subregion analysis modes (Fig. 2 ). ASM was calculated by summing the lean mass of the bilateral upper and lower limbs. To account for individual variations in body size, ASM was normalized by dividing it by the square of the patient's height (ASM/height² in kg/m²) and by the body mass index (ASM/BMI) [ 4 , 6 , 19 , 20 ]. Furthermore, recognizing that the cross-sectional area of the psoas muscle correlates well with whole-body skeletal muscle mass [ 21 – 23 ], we measured the normalized total psoas area (NTPA). The NTPA was obtained by summing the cross-sectional areas of the right and left psoas muscles at the midpoint of the L3-L4 disc space level on axial MRI images. This total area was then divided by the square of the patient's height to standardize the measurement (mm²/m²) [ 10 , 12 , 13 , 16 , 21 – 24 ] (Fig. 3 ). C onservative treatment protocol All patients included in the study underwent a minimum of three months of conservative treatment prior to consideration for surgery. The conservative treatment was implemented in stages, beginning with a combination of physical therapy and medication. Physical therapy focused on lumbar stabilization exercises, while medications included NSAIDs, limaprost, muscle relaxants and neuropathic agents such as pregabalin. If symptoms did not improve or worsened, epidural steroid injections were administered. Statistical analysis Interrater reliability of the muscle measurements was calculated by comparing the first measurements of 50 randomly chosen patients, independently completed by a second rater. In this analysis, the intraclass correlation (ICC) was used to compare the total CSA and Goutalier classification between both raters, assuming a two-way kappa statistic of agreement [ 25 ]. Kappa (κ) values were expressed with 95% confidence interval (CI) and interpretations of the level of agreement were categorized as follows: 0.00–0.20 (slight agreement), 0.21–0.40 (fair agreement), 0.41–0.60 (moderate agreement), 0.61–0.80 (substantial agreement), and 0.81–1.00 (almost perfect agreement). To identify risk factors of conservative treatment failure, we analyzed patients divided into two groups: patients who had successful conservative treatment (Group A) and patients who had failed conservative treatment and underwent surgery (Group B). We compared the measurements between two groups using the Student t -test and chi-squared test. Unadjusted odds ratios (OR) were generated using multiple logistic regression to determine the predictive factors for conservative treatment failure. The correlation between paraspinal sarcopenia and generalized sarcopenia assessments was evaluated using Spearman’s rank correlation coefficient (rho). The strength of the correlation was assessed according to established cut-offs (0 − 0.3, negligible; 0.3 − 0.5, low; 0.5 − 0.7, moderate; 0.7 − 0.9, high; ≥0.9, very high) [ 26 ]. The data were considered statistically significant if p < 0.05. All statistical analyses were performed using SPSS, version 26.0 (IBM Corp., Armonk, New York, USA). Results A total of 101 patients were evaluated for inclusion with a mean follow-up period of 14.7 months. The average duration of conservative treatment prior to surgery for patients in group B was 6.2 ± 2.5 months. Of the 101 patients, 71 were in group A and 30 were in group B. The mean patient age was 67.9 ± 10.7 years, with 26 men and 45 women, in group A and 71.2 ± 8.5 years, with 13 men and 17 women, in group B. The differences were not statistically significant between the two groups. The BMI values were 24.5 ± 3.4 kg/m 2 and 25.3 ± 3.8 kg/m 2 , respectively, showing no statistically significant difference. The prevalence of diabetes was higher in Group B (12 out of 30 patients, 40%) compared to Group A (20 out of 71 patients, approximately 28%). However, this difference was not statistically significant (p = 0.15). While diabetes was more common in the surgical group, it may not be a definitive predictor of conservative treatment failure in this sample. A higher proportion of current smokers was observed in Group B (7/30, 23%) compared to Group A (12/71, 17%), but this difference did not reach statistical significance (p = 0.45). The prevalence of osteoporosis was similar between the groups (Group A: 25/71, 35%; Group B: 12/30, 40%; p = 0.65), indicating no significant association with treatment outcomes. Spondylolisthesis was present in 27 patients (38%) in Group A and 16 patients (53.3%) in Group B; however, the difference was not statistically significant (p = 0.16). Significant segmental instability was observed in 8 patients (11%) in Group A and 9 patients (30%) in Group B, and this difference was statistically significant (p = 0.03) (Table 1). The CSAI of group A was higher than that of group B. However, the difference was not statistically significant between the two groups (Group A, 1339.29 ± 238.78 mm 2 /m 2 ; Group B, 1245.64 ± 286.78 mm 2 /m 2 ; p = 0.142). The CSA/BMI was significantly higher and the less fatty degeneration in the group A compared with the group B (CSA/BMI for group A, 143.29 ± 35.96; Group B, 123.73 ± 33.42; p < 0.05). Goutallier classification 1 and 2 accounted for 80.3% of group A and 53.3% of group B, while Goutallier classification 3 and 4 accounted for 19.7% of group A and 46.7% of group B ( p < 0.05) (Table 2 ). Table 1. Demographic Data Variable Conservative Therapy (n=71) Surgical Intervention (n=30) P Value Age(years) 0.16 Mean ± SD 67.9 ± 10.7 71.2 ± 8.5 Range 47 - 88 51 - 83 Sex (n) 0.53 Male 26 13 Female 45 17 BMI (kg/m 2 ) 24.5 ± 3.4 25.3 ± 3.8 0.4 Diabetes mellitus 20 (28%) 12 (40%) 0.15 Smoking (current smokers) 12 (17%) 7 (30%) 0.45 Osteoporosis 25 (35%) 12 (40%) 0.65 Chronic kidney disease 5 (7%) 3 (10%) 0.68 Cardiovascular disease 18 (25%) 9 (30%) 0.6 Spondylolisthesis 27 (38%) 16 (53.3%) 0.16 Segmental instability 8 (11%) 9 (30%) 0.03 SD, standard deviation; BMI, body mass index The ASMI and ASM/BMI of group A were higher than that of group B. However, the difference was not statistically significant between the two groups (ASMI for Group A, 5.98 ± 1.15 kg/m 2 ; Group B, 5.79 ± 1.18 kg/m 2 ; p = 0.535; ASM/BMI for Group A, 0.64 ± 0.17; Group B, 0.57 ± 0.15; p = 0.126). The NTPA was also higher in group A, but there was no statistically significant difference (Group A, 785.63 ± 205.69 mm 2 /m 2 ; Group B, 720.8 ± 226.91 mm 2 /m 2 ; p = 0.227). According to the cut-off points presented in EWGSOP2 [ 1 ], the proportion of patients with sarcopenia based on generalized sarcopenia measurements was 49.3% in group A, which was lower than 53.3% in group B, but there was no statistically significant difference ( p = 0.828) (Table 3 ). Table 2. Paraspinal Muscle Quality Variable Group A (n=71) Group B (n=30) P Value CSAI (mm 2 /m 2 ) 1339.29 ± 238.78 1245.64 ± 286.78 0.142 CSA/BMI 143.29 ± 35.96 123.73 ± 33.42 0.032 Goutallier classification 0.003 1 (n (%)) 21 (29.6) 3 (10) 2 (n (%)) 36 (50.7) 13 (43.3) 3 (n (%)) 10 (14.1) 9 (30) 4 (n (%)) 4 (5.6) 5 (16.7) CSA, cross-sectional area; CSAI, cross-sectional area index; BMI, body mass index Table 3. Generalized Sarcopenia Parameters Variable Group A (n=71) Group B (n=30) P Value ASMI (kg/m 2 ) 5.98 ± 1.15 5.79 ± 1.18 0.535 ASM/BMI 0.64 ± 0.17 0.57 ± 0.15 0.126 NTPA (mm 2 /m 2 ) 785.63 ± 205.69 720.8 ± 226.91 0.227 Sarcopenia (n (%)) 35 (49.3) 16 (53.3) 0.828 ASM, appendicular skeletal muscle mass; ASMI, appendicular skeletal muscle mass index; BMI, body mass index, NTPA, Normalized total psoas area The ICC for the NTPA 0.93 (95% CI 0.92 − 0.94). The ICC for the total CSA and FI (Goutalier classification) of the paraspinal muscle is 0.91 (95% CI 0.90 − 0.93) and 0.90 (95% CI 0.83 − 0.97). Multiple logistic regression analysis showed statistically significant predictive factors for failure of conservative treatment. The CSA/BMI (OR: 0.983, 95% CI, 0.968–0.999, p = 0.037) was only independently associated with failure of conservative treatment in our secondary analysis. Even after adjusting for segmental instability, the CSA/BMI of the paraspinal muscles remained an independent predictor of conservative treatment failure (adjusted OR: 0.982, 95% CI: 0.967–0.998, p = 0.028). ASM/BMI demonstrated the highest correlation with CSA/BMI (rho = 0.73, p < 0.001) among the generalized sarcopenia parameters; the other correlations were statistically significant ( p < 0.001) but lower in strength (Table 4 ). CSA/BMI demonstrated the highest correlation with fatty degeneration of paraspinal muscles (rho = -0.6, p < 0.001) among the paraspinal and generalized sarcopenia measurements. Table 4. Results of Correlation Analysis Between CSA/BMI and Generalized Sarcopenia Parameters Factor Correlation with CSA/BMI (n = 101) Coefficient P Value ASMI (kg/m 2 ) 0.388 <0.001 ASM/BMI 0.730 <0.001 NTPA (mm 2 /m 2 ) 0.440 <0.001 ASM, appendicular skeletal muscle mass; ASMI, appendicular skeletal muscle mass index; BMI, body mass index, NTPA, Normalized total psoas area Discussion The present study investigates the concordance between various assessment tools for generalized and paraspinal sarcopenia among patients with degenerative LSS and identifies risk factors predicting conservative treatment failure. To the best of our knowledge, this is the first study to investigate the association between sarcopenia and the prognosis of conservative treatment in patients with degenerative spinal diseases. Our findings provide significant insights into the intricate relationship between sarcopenia and LSS, emphasizing the need for distinct diagnostic approaches. This distinction is crucial for the clinical assessment and management of spinal conditions. Recent research supports the idea that spine-specific sarcopenia should be given greater importance in the context of spinal diseases. Schonnagel et al. highlighted that paraspinal muscle atrophy, rather than generalized sarcopenia, significantly impacts functional outcomes and pain levels in patients with spinal disorders [ 15 ]. Similarly, Pinter et al. found that worse paraspinal muscle quality was associated with poorer patient-reported outcomes following spinal surgeries, reinforcing the need for targeted evaluation of paraspinal muscles [ 18 ]. Furthermore, Chang et al. demonstrated that paraspinal lean muscle mass measured via MRI could predict adjacent segment disease after lumbar fusion, suggesting the importance of paraspinal muscle health in postoperative prognosis [ 4 ]. These findings align with our results, which indicate that better-preserved paraspinal muscle mass and lower fatty degeneration are associated with more favorable outcomes in conservative treatment of lumbar spinal stenosis. The results of this study highlight the distinct role of paraspinal sarcopenia in patients with degenerative LSS, differentiating it from generalized sarcopenia. Our findings demonstrate a weak correlation between generalized sarcopenia and the prognosis of LSS, suggesting that generalized and spine-specific sarcopenia may arise from different etiologies. This observation is crucial as it raises concerns about the potential for misdiagnosis when using screening tools designed primarily for generalized sarcopenia in the context of spinal disorders [ 15 , 27 – 29 ]. The analysis revealed that the CSA and CSA/BMI of the paraspinal muscles were significantly higher in patients who responded well to conservative treatment compared to those who eventually required surgical intervention. This indicates that better-preserved paraspinal muscle mass and lower fatty degeneration are associated with more favorable outcomes in conservative treatment of LSS. Specifically, the CSA/BMI was independently associated with conservative treatment failure, suggesting its potential utility as a predictive marker for treatment outcomes [ 12 , 16 – 18 , 30 – 32 ]. Contrary to the paraspinal measurements, generalized sarcopenia indices such as ASMI, ASM/BMI and NTPA did not show significant differences between the two patient groups. This further supports the notion that paraspinal muscle health might play a more critical role in the management of LSS than generalized muscle mass [ 4 ]. The lack of significant differences in generalized sarcopenia measurements between successful and failed conservative treatment groups underscores the importance of focusing on paraspinal muscle health in the clinical assessment and management of LSS [ 33 ]. Additionally, we analyzed the impact of spondylolisthesis and segmental instability on treatment outcomes. Our results showed that while spondylolisthesis was more prevalent in the surgical group (Group B), the difference was not statistically significant (p = 0.16). This aligns with previous studies indicating that the natural history of degenerative spondylolisthesis is generally favorable, with only 10–15% of patients eventually requiring surgery after seeking treatment. Long-term follow-up studies have found that progression of vertebral slippage in non-surgically managed patients does not necessarily correlate with changes in clinical symptoms, supporting our finding that spondylolisthesis may not significantly affect conservative treatment failure [ 9 , 34 ]. In contrast, segmental instability showed a statistically significant association with conservative treatment failure (p = 0.03), suggesting that it may contribute to symptom worsening and increase the need for surgical intervention. Therefore, segmental instability should be considered an important factor in predicting the prognosis of conservative treatment. Previous studies have emphasized the clinical significance of psoas CSA in spine surgery, demonstrating its correlation with postoperative mortality, adverse events and functional outcomes after surgery [ 13 , 16 , 17 , 24 ]. However, the results of this study differed from previous research. There was no significant difference in the CSA of the psoas muscle between groups A and B. Additionally, logistic regression analysis did not yield significant results (OR: 0.999, 95% CI, 0.995–1.002, p = 0.542), and the correlation with CSA/BMI was also low (Table 4 ). The CSA of the psoas muscle appears to have some utility as an assessment tool for postoperative outcomes and prognosis in spinal surgery patients. However, it seems insufficient as an indicator for evaluating the non-operative patients. Particularly in cases of degenerative spinal diseases, the assessment of the paraspinal muscles provides a more appropriate indicator for sarcopenia compared to the psoas muscle [ 4 , 11 , 14 , 15 , 18 , 30 , 35 ]. Anatomically, the erector spinae muscles are directly involved in maintaining spinal stability and posture, which are critical in the pathophysiology of spinal degeneration. Unlike the psoas muscle, which primarily functions in hip flexion, the erector spinae muscles bear the brunt of compensatory mechanisms during spinal deterioration. Furthermore, the degeneration of the erector spinae muscles closely correlates with functional impairment and pain in patients, making it a more precise marker for sarcopenia. From a biomechanical perspective, the erector spinae muscles' endurance and strength are pivotal in mitigating the progression of spinal degeneration [ 36 , 37 ]. Based on the results of this study, it is inferred that standardizing muscle CSA measurements using BMI, rather than height squared, would result in greater accuracy in the assessment of sarcopenia. This approach aligns with the latest guidelines from the Asian Working Group for Sarcopenia (AWGS) [ 38 ]. BMI incorporates both weight and height, providing a more comprehensive reflection of an individual's body composition. This can improve the sensitivity and specificity of CSA measurements in diagnosing sarcopenia. However, there remains ongoing debate regarding the optimal adjustment method and whether a single approach can be universally applied across different populations. Thus, future studies should further investigate the comparative effectiveness of these standardization methods to establish a more precise diagnostic criterion. This study has several limitations that need to be considered. Firstly, the retrospective nature of the study design may introduce selection bias, as it relies on previously collected data from medical records. Secondly, we identified patients using the diagnosis code for lumbar spinal stenosis from our hospital's electronic medical records. Over a 10-year period, only 101 patients met our inclusion criteria, which is a relatively small sample size. This number appears limited due to our strict inclusion criteria—specifically, the requirement that patients had both MRI and DXA examinations within a 6-month interval, had undergone at least 3 months of conservative treatment, and had a minimum of 1-year follow-up data. The stringent criteria may have introduced selection bias and limited the sample size, potentially affecting the generalizability of our findings. Additionally, the study population was drawn from a single institution, which may not represent the broader population. The time interval between MRI and DXA examinations varied, potentially affecting the accuracy of muscle measurements. Another limitation of our study is the use of cross-sectional (2-D) muscle measurements rather than volumetric (3-D) analysis. Volumetric muscle assessment could provide a more accurate and comprehensive evaluation of muscle mass and quality. However, due to the retrospective nature of our study and the limitations of the imaging protocols used, volumetric analysis was not feasible. Future prospective studies employing advanced imaging techniques and standardized protocols for volumetric muscle assessment are needed to further elucidate the relationships between localized muscle volume and systemic muscle mass. Furthermore, we did not account for variations in physical activity levels, nutritional status, or other comorbidities that could impact muscle mass and function. Lastly, the assessment of muscle quality was based on imaging techniques, which may not fully capture the functional aspects of sarcopenia. Conclusion In conclusion, this study highlights the distinct role of paraspinal sarcopenia in patients with degenerative LSS, distinguishing it from generalized sarcopenia. The findings indicate a weak correlation between generalized sarcopenia and the prognosis of LSS, suggesting that these conditions may have different etiologies. This underscores the need for tailored diagnostic approaches that consider the unique characteristics of paraspinal sarcopenia. Future research should focus on elucidating these specific etiologies to better inform treatment strategies and improve patient outcomes. Additionally, larger studies with extended follow-up periods are warranted to further investigate these relationships and aid in the development of more precise diagnostic tools. Declarations Author Contribution All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by S.M. and J.W.. The first draft of the manuscript was written by S.M. and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript. 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Spine J 22:1677-1686. doi: 10.1016/j.spinee.2022.05.013 Song J, Shahsavarani S, Vatsia S, Katz AD, Ngan A, Fallon J, Strigenz A, Seitz M, Silber J, Essig D, Qureshi SA, Virk S (2023) Association between history of lumbar spine surgery and paralumbar muscle health: a propensity score-matched analysis. Spine J 23:1659-1666. doi: 10.1016/j.spinee.2023.07.004 Pinter ZW, Reed R, Townsley SE, Mikula AL, Lakomkin N, Kazarian E, Michalopoulos GD, Freedman BA, Currier BL, Elder BD, Bydon M, Fogelson J, Sebastian AS, Nassr AN (2023) Paraspinal Sarcopenia is Associated With Worse Patient-Reported Outcomes Following Laminoplasty for Degenerative Cervical Myelopathy. Spine (Phila Pa 1976) 48:772-781. doi: 10.1097/BRS.0000000000004650 Chen Z, Wang Z, Lohman T, Heymsfield SB, Outwater E, Nicholas JS, Bassford T, LaCroix A, Sherrill D, Punyanitya M, Wu G, Going S (2007) Dual-energy X-ray absorptiometry is a valid tool for assessing skeletal muscle mass in older women. J Nutr 137:2775-2780. doi: 10.1093/jn/137.12.2775 Lee SY, Kim DH, Park SJ, Park J, Chung SG, Lim JY (2021) Novel lateral whole-body dual-energy X-ray absorptiometry of lumbar paraspinal muscle mass: results from the SarcoSpine study. J Cachexia Sarcopenia Muscle 12:913-920. doi: 10.1002/jcsm.12721 Jones K, Doleman B, Scott S, Lund JN, Williams JP (2015) Simple psoas cross‐sectional area measurement is a quick and easy method to assess sarcopenia and predicts major surgical complications. Colorectal disease 17:O20-O26 Onesti JK, Wright GP, Kenning SE, Tierney MT, Davis AT, Doherty MG, Chung MH (2016) Sarcopenia and survival in patients undergoing pancreatic resection. Pancreatology 16:284-289 Valero III V, Amini N, Spolverato G, Weiss MJ, Hirose K, Dagher NN, Wolfgang CL, Cameron AA, Philosophe B, Kamel IR (2015) Sarcopenia adversely impacts postoperative complications following resection or transplantation in patients with primary liver tumors. Journal of Gastrointestinal Surgery 19:272-281 Moser M, Adl Amini D, Jones C, Zhu J, Okano I, Oezel L, Chiapparelli E, Tan ET, Shue J, Sama AA, Cammisa FP, Girardi FP, Hughes AP (2023) The predictive value of psoas and paraspinal muscle parameters measured on MRI for severe cage subsidence after standalone lateral lumbar interbody fusion. Spine J 23:42-53. doi: 10.1016/j.spinee.2022.03.009 Koo TK, Li MY (2016) A guideline of selecting and reporting intraclass correlation coefficients for reliability research. Journal of chiropractic medicine 15:155-163 Schober P, Boer C, Schwarte LA (2018) Correlation Coefficients: Appropriate Use and Interpretation. Anesthesia & Analgesia 126:1763-1768. doi: 10.1213/ane.0000000000002864 Charest-Morin R, Street J, Zhang H, Roughead T, Ailon T, Boyd M, Dvorak M, Kwon B, Paquette S, Dea N, Fisher CG, Flexman AM (2018) Frailty and sarcopenia do not predict adverse events in an elderly population undergoing non-complex primary elective surgery for degenerative conditions of the lumbar spine. Spine J 18:245-254. doi: 10.1016/j.spinee.2017.07.003 Moskven E, Bourassa-Moreau E, Charest-Morin R, Flexman A, Street J (2018) The impact of frailty and sarcopenia on postoperative outcomes in adult spine surgery. A systematic review of the literature. Spine J 18:2354-2369. doi: 10.1016/j.spinee.2018.07.008 Moskven E, Lasry O, Singh S, Flexman AM, Street JT, Dea N, Fisher CG, Ailon T, Dvorak MF, Kwon BK, Paquette SJ, Charest-Morin R (2023) The Role of Frailty and Sarcopenia in Predicting Major Adverse Events, Length of Stay and Reoperation Following En Bloc Resection of Primary Tumours of the Spine. Global Spine J:21925682231173360. doi: 10.1177/21925682231173360 Han G, Wu H, Dai J, Li X, Yue L, Fan Z, Li Q, Shao Q, Jiang Y, Li W (2023) Does paraspinal muscle morphometry predict functional status and re-operation after lumbar spinal surgery? A systematic review and meta-analysis. Eur Radiol 33:5269-5281. doi: 10.1007/s00330-023-09548-6 Matsuo S, Kawakami M, Minetama M, Nakagawa M, Teraguchi M, Kagotani R, Mera Y, Yamamoto Y, Sakon N, Nakatani T, Sumiya T, Nakagawa Y (2020) Clinical Features of Sarcopenia in Patients With Lumbar Spinal Stenosis. Spine (Phila Pa 1976) 45:E1105-E1110. doi: 10.1097/BRS.0000000000003498 Schlaeger S, Inhuber S, Rohrmeier A, Dieckmeyer M, Freitag F, Klupp E, Weidlich D, Feuerriegel G, Kreuzpointner F, Schwirtz A, Rummeny EJ, Zimmer C, Kirschke JS, Karampinos DC, Baum T (2019) Association of paraspinal muscle water-fat MRI-based measurements with isometric strength measurements. Eur Radiol 29:599-608. doi: 10.1007/s00330-018-5631-8 Kitsuda Y, Wada T, Tanishima S, Osaki M, Nagashima H, Hagino H (2023) Impact of Sarcopenia on Spinal Spondylosis: A Literature Review. J Clin Med 12. doi: 10.3390/jcm12165401 Kalichman L, Hunter DJ (2008) Diagnosis and conservative management of degenerative lumbar spondylolisthesis. Eur Spine J 17:327-335. doi: 10.1007/s00586-007-0543-3 Lee JC, Cha JG, Kim Y, Kim YI, Shin BJ (2008) Quantitative analysis of back muscle degeneration in the patients with the degenerative lumbar flat back using a digital image analysis: comparison with the normal controls. Spine (Phila Pa 1976) 33:318-325. doi: 10.1097/BRS.0b013e318162458f Hu Z-J, Fang X-Q, Fan S-W (2014) Iatrogenic injury to the erector spinae during posterior lumbar spine surgery: underlying anatomical considerations, preventable root causes, and surgical tips and tricks. European Journal of Orthopaedic Surgery & Traumatology 24:127-135 Yazici A, Yerlikaya T (2022) The relationship between the degeneration and asymmetry of the lumbar multifidus and erector spinae muscles in patients with lumbar disc herniation with and without root compression. Journal of Orthopaedic Surgery and Research 17:541 Ochi M, Kohara K, Tabara Y, Kido T, Uetani E, Ochi N, Igase M, Miki T (2010) Arterial stiffness is associated with low thigh muscle mass in middle-aged to elderly men. Atherosclerosis 212:327-332 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 07 Oct, 2025 Read the published version in Clinical Spine Surgery → Version 1 posted 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. 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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-5400496","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":389975914,"identity":"657725b2-aedf-4d55-ae3f-75b8d7a1d326","order_by":0,"name":"Jinwoo Jin","email":"","orcid":"","institution":"Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon","correspondingAuthor":false,"prefix":"","firstName":"Jinwoo","middleName":"","lastName":"Jin","suffix":""},{"id":389975915,"identity":"cf60b1ed-bf3b-400f-87b3-8d7b536a1fe4","order_by":1,"name":"Seung Myung Wi","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA2ElEQVRIiWNgGAWjYDACCcbGA0CKh4G9AUgZWBClpQGihQdEGUgQo4WB4QCEkQDlEgL8s5sbDn5tuycjP/P51Q0/CiQY+Nu7E/Bbcudgw2HZtmIeg9s5ZTd7gA6TOHN2A14tBhKJDYcl2xJ4DKRz0m7wALUYSOQSqUV+5pm0m3+I1XLwI1ALww32Y7eJskXiBtAWhnNAh53JYbstYyDBQ9Av/DPSHz78UZZgL99+/NnNN39s5Pjbe/FrAQFmHjDFYwAmCSoHAcYfYIr9AVGqR8EoGAWjYOQBAB8ySZ9MZ/VvAAAAAElFTkSuQmCC","orcid":"","institution":"Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon","correspondingAuthor":true,"prefix":"","firstName":"Seung","middleName":"Myung","lastName":"Wi","suffix":""}],"badges":[],"createdAt":"2024-11-06 07:38:27","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5400496/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5400496/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1097/BSD.0000000000001945","type":"published","date":"2025-10-08T00:00:00+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":71800828,"identity":"19c57cce-5221-488a-b71a-27ce6fd35686","added_by":"auto","created_at":"2024-12-18 16:50:41","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":881606,"visible":true,"origin":"","legend":"\u003cp\u003eA representative magnetic resonance imaging (MRI) slice of a 68-year-old woman with central canal stenosis, depicting the technique for measuring the paralumbar multifidus and erector spinae muscles cross-sectional area (CSA) (red outlines). Measurements were performed on the same axial slice on T2-weighted MRI at the middle of the midpoint of the L4-L5 disc space level (total CSA = left + right). The measurements were automatically calculated using the PACS system. Next, all measured data were averaged. The measure was standardized by dividing by the height squared (CSA index; CSAI) and BMI (CSA/BMI). Max, maximum; Min, minimum; SD, standard deviation.\u003c/p\u003e","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-5400496/v1/0ca91c850f951e307f37bf0e.png"},{"id":71800827,"identity":"8af385fa-3499-4f99-937a-4506c18a7201","added_by":"auto","created_at":"2024-12-18 16:50:41","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":565002,"visible":true,"origin":"","legend":"\u003cp\u003eWhole-body Dual Energy X-ray Absorptiometry (DXA) results of a 58-year-old female patient, properly positioned according to Hologic manufacturer guidelines. Appendicular Skeletal Muscle (ASM) is calculated as the sum of lean muscle mass of both arms and legs, as indicated by the highlighted regions on the scan. ASM is used to assess generalized sarcopenia by normalizing it to the square of the patient's height (ASM/height²) or to the body mass index (ASM/BMI). YN, Young Normal; AM, Age Matched; L, Left; R, Right\u003c/p\u003e","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-5400496/v1/9fd5ef3b57e429f79920e9ff.png"},{"id":71800826,"identity":"add6e802-3d77-4fc7-94cf-24ddbe03c769","added_by":"auto","created_at":"2024-12-18 16:50:41","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":485398,"visible":true,"origin":"","legend":"\u003cp\u003eExample bilateral psoas muscle cross-sectional area (CSA) measurements on axial T2-weighted magnetic resonance image at the midpoint of the L3-L4 disc space level (total psoas area = left + right) (red outlines). The measurements were automatically calculated using the PACS system. Next, the total psoas area index was calculated using the following equation: Normalized total psoas area (NTPA) = total psoas muscle area (cm\u003csup\u003e2\u003c/sup\u003e)/height squared (m\u003csup\u003e2\u003c/sup\u003e). Max, maximum; Min, minimum; SD, standard deviation.\u003c/p\u003e","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-5400496/v1/a05ceb90d67fd36f3ec18bea.png"},{"id":96411065,"identity":"b68cb2d1-d4a4-4278-8374-acb87258ca31","added_by":"auto","created_at":"2025-11-20 18:40:42","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2461700,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5400496/v1/28f43367-8e76-4263-a46f-ccc68c5f0f7e.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"The Impact of Paraspinal Sarcopenia Compared to Generalized Sarcopenia on Conservative Treatment Outcomes in Degenerative Lumbar Spinal Stenosis","fulltext":[{"header":"Introduction","content":"\u003cp\u003eSarcopenia is a condition characterized by a progressive, age-related decline in skeletal muscle mass, strength, and function. The European Working Group on Sarcopenia in Older People (EWGSOP) has established sarcopenia as a progressive and widespread skeletal muscle disorder with a heightened risk of adverse outcomes [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. In its second meeting (EGWSOP2), the definition of sarcopenia was refined to encompass diminished muscle strength, reduced muscle mass, and impaired physical performance. EGWSOP2 further delineated between acute and chronic presentations, as well as between idiopathic (age-related) and secondary sarcopenia. To identify and assess the severity of sarcopenia, EWGSOP2 recommends employing various screening methods, including grip strength assessments, evaluation of appendicular or central muscle mass, and performance tests such as the short physical performance battery (SPPB) [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Advances in imaging technologies have enhanced the ability to evaluate and diagnose sarcopenia, leading to a growing body of research on its impact, particularly within the context of spinal diseases. Currently, magnetic resonance imaging (MRI) and computed tomography (CT) are regarded as the gold standard techniques for assessing the quantity of paraspinal muscles. Dual energy X-ray absorptiometry (DXA) is regarded as the reference standard for assessing body muscle mass. DXA provides detailed measurements of both regional and total body muscle quantity, offering absolute values of lean mass (LM) as well as LM indices such as appendicular skeletal muscle mass (ASM) [\u003cspan additionalcitationids=\"CR4 CR5\" citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Lumbar spinal stenosis (LSS) arises from degenerative changes in the spine, causing narrowing of central canal, lateral recess, and/or neural foramen (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). This condition, prevalent among the elderly, significantly impacts their quality of life and is a primary reason for spine surgery [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Research suggests that 33\u0026ndash;50% of patients with mild to moderate LSS may experience positive outcomes without surgical intervention. Despite anecdotal concerns, rapid neurological decline is rare in these cases [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Surgical decompression is reserved for patients not responding to conservative treatments [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eRecent studies have started to explore the relationship between paraspinal muscle sarcopenia and generalized sarcopenia, revealing a complex interplay between these conditions and spinal disorders. However, significant uncertainties remain, including the extent to which paraspinal muscle sarcopenia correlates with generalized sarcopenia, as well as how generalized sarcopenia influences the progression and treatment outcomes of spinal diseases. Furthermore, all studies on this topic have studied the impact of sarcopenia on postoperative outcomes, such as lumbar decompression surgery or lumbar spinal fusion, rather than the prognosis of conservative treatment [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan additionalcitationids=\"CR11 CR12 CR13 CR14 CR15 CR16\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. The aim of this study is to investigate the concordance between various assessment tools for generalized and paraspinal sarcopenia among patients with degenerative spinal stenosis. Additionally, we seek to identify risk factors that could predict conservative treatment failure and poor clinical outcomes in this patient population. By addressing these objectives, this study aims to provide new insights into the diagnosis and management of sarcopenia in the context of spinal disease.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003e Upon obtaining approval from the Institutional Review Board (IRB) (Samsung Changwon Hospital of Sungkyunkwan University IRB; Approval No.2024-04-009), informed consent was waived by the IRB due to the retrospective nature of the study. We performed a retrospective review of 101 degenerative lumbar spinal stenosis patients with MRI and whole-body DXA who have undergone at least three months of conservative treatment at a single institution between 2013 and 2023. We excluded patients from the study if the time interval between MRI and DXA examination was more than 6 months or if the patient did not have 1-year follow-up data. Also, we excluded patients with peripheral neuropathy including diabetic neuropathy, myopathy, myelopathy, congenital anomalies such as spondylolysis or congenital spinal stenosis and cerebrovascular disease (defined as any history of stroke, transient ischemic attack, or other significant cerebrovascular events causing neurological deficits). Finally, patients with a history of previous lumbar spine surgery were excluded. The reporting of this study is in accordance with the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines. Muscle measurements were performed by two independent reviewers, a board-certified musculoskeletal radiologist and a spine surgeon with over 10 years of experience. They were blinded to the clinical history of the patients while analyzing axial T2 MRIs using our institution\u0026rsquo;s PACS system [INFINITT Healthcare Co., Ltd., Seoul, Republic of Korea].\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eParaspinal Sarcopenia measurements\u003c/h2\u003e \u003cp\u003eParaspinal sarcopenia was determined by assessing the cross-sectional area (CSA) and fatty infiltration of the paraspinal muscles (multifidus and erector spinae) using axial T2-weighted MRI images at the midpoint of the L4-L5 disc space level (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The CSA was measured by tracing the fascial boundary of these muscles on both sides. This regional measurement focuses on muscles directly involved in spinal support and function. All measured data were averaged. The measure was standardized by dividing by the height squared (CSA index; CSAI) and BMI (CSA/BMI) [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan additionalcitationids=\"CR15\" citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Fatty degeneration was evaluated using the Goutallier classification, which qualitatively grades the extent of intramuscular fat infiltration on a scale from 0 to 4. Goutallier classes were defined as follows: \u0026lsquo;0\u0026rsquo; if there were no visible fat streaks in the muscle, \u0026lsquo;1\u0026rsquo; if there were minimal fatty streaks in the muscle, \u0026lsquo;2\u0026rsquo; if there was more muscle present than fat, \u0026lsquo;3\u0026rsquo; if fat and muscle were present in equal quantity, and \u0026lsquo;4\u0026rsquo; if more fat was present than muscle. (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eGeneralized Sarcopenia measurements\u003c/h3\u003e\n\u003cp\u003eGeneralized sarcopenia was evaluated using whole-body dual-energy X-ray absorptiometry (DXA) scans (Horizon W; Hologic, MA), as recommended by the EWGSOP2 [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. DXA provides a systemic assessment of muscle mass by measuring lean soft tissue mass across the entire body. Patients were scanned while wearing only hospital gowns to prevent artifacts, following our institution's standard protocol. The whole-body scans were manually analyzed using the Hologic QDR System software (version 13.6), following the manufacturer's guidelines for regions of interest (ROIs). We assessed both regional and total body muscle quantities. Standard ROIs included measurements of the arms, legs, trunk, and total body. Customized ROIs were also analyzed to focus on specific areas such as the total leg, upper leg, and lower leg, utilizing the software's subregion analysis modes (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eASM was calculated by summing the lean mass of the bilateral upper and lower limbs. To account for individual variations in body size, ASM was normalized by dividing it by the square of the patient's height (ASM/height\u0026sup2; in kg/m\u0026sup2;) and by the body mass index (ASM/BMI) [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eFurthermore, recognizing that the cross-sectional area of the psoas muscle correlates well with whole-body skeletal muscle mass [\u003cspan additionalcitationids=\"CR22\" citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e], we measured the normalized total psoas area (NTPA). The NTPA was obtained by summing the cross-sectional areas of the right and left psoas muscles at the midpoint of the L3-L4 disc space level on axial MRI images. This total area was then divided by the square of the patient's height to standardize the measurement (mm\u0026sup2;/m\u0026sup2;) [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan additionalcitationids=\"CR22 CR23\" citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e] (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eC\u003cem\u003eonservative treatment protocol\u003c/em\u003e\u003c/p\u003e \u003cp\u003eAll patients included in the study underwent a minimum of three months of conservative treatment prior to consideration for surgery. The conservative treatment was implemented in stages, beginning with a combination of physical therapy and medication. Physical therapy focused on lumbar stabilization exercises, while medications included NSAIDs, limaprost, muscle relaxants and neuropathic agents such as pregabalin. If symptoms did not improve or worsened, epidural steroid injections were administered.\u003c/p\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eInterrater reliability of the muscle measurements was calculated by comparing the first measurements of 50 randomly chosen patients, independently completed by a second rater. In this analysis, the intraclass correlation (ICC) was used to compare the total CSA and Goutalier classification between both raters, assuming a two-way kappa statistic of agreement [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. Kappa (κ) values were expressed with 95% confidence interval (CI) and interpretations of the level of agreement were categorized as follows: 0.00\u0026ndash;0.20 (slight agreement), 0.21\u0026ndash;0.40 (fair agreement), 0.41\u0026ndash;0.60 (moderate agreement), 0.61\u0026ndash;0.80 (substantial agreement), and 0.81\u0026ndash;1.00 (almost perfect agreement). To identify risk factors of conservative treatment failure, we analyzed patients divided into two groups: patients who had successful conservative treatment (Group A) and patients who had failed conservative treatment and underwent surgery (Group B). We compared the measurements between two groups using the Student \u003cem\u003et\u003c/em\u003e-test and chi-squared test. Unadjusted odds ratios (OR) were generated using multiple logistic regression to determine the predictive factors for conservative treatment failure. The correlation between paraspinal sarcopenia and generalized sarcopenia assessments was evaluated using Spearman\u0026rsquo;s rank correlation coefficient (rho). The strength of the correlation was assessed according to established cut-offs (0\u0026thinsp;\u0026minus;\u0026thinsp;0.3, negligible; 0.3\u0026thinsp;\u0026minus;\u0026thinsp;0.5, low; 0.5\u0026thinsp;\u0026minus;\u0026thinsp;0.7, moderate; 0.7\u0026thinsp;\u0026minus;\u0026thinsp;0.9, high; \u0026ge;0.9, very high) [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. The data were considered statistically significant if \u003cem\u003ep\u0026thinsp;\u0026lt;\u003c/em\u003e\u0026thinsp;0.05. All statistical analyses were performed using SPSS, version 26.0 (IBM Corp., Armonk, New York, USA).\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eA total of 101 patients were evaluated for inclusion with a mean follow-up period of 14.7 months. The average duration of conservative treatment prior to surgery for patients in group B was 6.2\u0026thinsp;\u0026plusmn;\u0026thinsp;2.5 months. Of the 101 patients, 71 were in group A and 30 were in group B. The mean patient age was 67.9\u0026thinsp;\u0026plusmn;\u0026thinsp;10.7 years, with 26 men and 45 women, in group A and 71.2\u0026thinsp;\u0026plusmn;\u0026thinsp;8.5 years, with 13 men and 17 women, in group B. The differences were not statistically significant between the two groups. The BMI values were 24.5\u0026thinsp;\u0026plusmn;\u0026thinsp;3.4 kg/m\u003csup\u003e2\u003c/sup\u003e and 25.3\u0026thinsp;\u0026plusmn;\u0026thinsp;3.8 kg/m\u003csup\u003e2\u003c/sup\u003e, respectively, showing no statistically significant difference. The prevalence of diabetes was higher in Group B (12 out of 30 patients, 40%) compared to Group A (20 out of 71 patients, approximately 28%). However, this difference was not statistically significant (p\u0026thinsp;=\u0026thinsp;0.15). While diabetes was more common in the surgical group, it may not be a definitive predictor of conservative treatment failure in this sample. A higher proportion of current smokers was observed in Group B (7/30, 23%) compared to Group A (12/71, 17%), but this difference did not reach statistical significance (p\u0026thinsp;=\u0026thinsp;0.45). The prevalence of osteoporosis was similar between the groups (Group A: 25/71, 35%; Group B: 12/30, 40%; p\u0026thinsp;=\u0026thinsp;0.65), indicating no significant association with treatment outcomes. Spondylolisthesis was present in 27 patients (38%) in Group A and 16 patients (53.3%) in Group B; however, the difference was not statistically significant (p\u0026thinsp;=\u0026thinsp;0.16). Significant segmental instability was observed in 8 patients (11%) in Group A and 9 patients (30%) in Group B, and this difference was statistically significant (p\u0026thinsp;=\u0026thinsp;0.03) (Table\u0026nbsp;1).\u003c/p\u003e\n\u003cp\u003eThe CSAI of group A was higher than that of group B. However, the difference was not statistically significant between the two groups (Group A, 1339.29\u0026thinsp;\u0026plusmn;\u0026thinsp;238.78 mm\u003csup\u003e2\u003c/sup\u003e/m\u003csup\u003e2\u003c/sup\u003e; Group B, 1245.64\u0026thinsp;\u0026plusmn;\u0026thinsp;286.78 mm\u003csup\u003e2\u003c/sup\u003e/m\u003csup\u003e2\u003c/sup\u003e; \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.142). The CSA/BMI was significantly higher and the less fatty degeneration in the group A compared with the group B (CSA/BMI for group A, 143.29\u0026thinsp;\u0026plusmn;\u0026thinsp;35.96; Group B, 123.73\u0026thinsp;\u0026plusmn;\u0026thinsp;33.42; \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). Goutallier classification 1 and 2 accounted for 80.3% of group A and 53.3% of group B, while Goutallier classification 3 and 4 accounted for 19.7% of group A and 46.7% of group B (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) (Table\u0026nbsp;\u003cspan\u003e2\u003c/span\u003e).\u003c/p\u003e\n\u003cdiv\u003e\n \u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"510\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd colspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eTable 1. Demographic Data\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariable\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eConservative Therapy\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n=71)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eSurgical Intervention\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n=30)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eP\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;Value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eAge(years)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.16\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eMean \u0026plusmn; SD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e67.9 \u0026plusmn; 10.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e71.2 \u0026plusmn; 8.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eRange\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e47 - 88\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e51 - 83\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eSex (n)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.53\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eMale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eFemale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eBMI (kg/m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e24.5 \u0026plusmn; 3.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e25.3 \u0026plusmn; 3.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eDiabetes mellitus\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e20 (28%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e12 (40%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.15\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eSmoking (current smokers)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e12 (17%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e7 (30%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.45\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eOsteoporosis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e25 (35%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e12 (40%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.65\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003eChronic kidney disease\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e5 (7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e3 (10%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.68\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eCardiovascular disease\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e18 (25%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e9 (30%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003eSpondylolisthesis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e27 (38%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e16 (53.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.16\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eSegmental instability\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8 (11%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e9 (30%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.03\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd colspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003eSD, standard deviation; BMI, body mass index\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eThe ASMI and ASM/BMI of group A were higher than that of group B. However, the difference was not statistically significant between the two groups (ASMI for Group A, 5.98\u0026thinsp;\u0026plusmn;\u0026thinsp;1.15 kg/m\u003csup\u003e2\u003c/sup\u003e; Group B, 5.79\u0026thinsp;\u0026plusmn;\u0026thinsp;1.18 kg/m\u003csup\u003e2\u003c/sup\u003e; \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.535; ASM/BMI for Group A, 0.64\u0026thinsp;\u0026plusmn;\u0026thinsp;0.17; Group B, 0.57\u0026thinsp;\u0026plusmn;\u0026thinsp;0.15; \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.126). The NTPA was also higher in group A, but there was no statistically significant difference (Group A, 785.63\u0026thinsp;\u0026plusmn;\u0026thinsp;205.69 mm\u003csup\u003e2\u003c/sup\u003e/m\u003csup\u003e2\u003c/sup\u003e; Group B, 720.8\u0026thinsp;\u0026plusmn;\u0026thinsp;226.91 mm\u003csup\u003e2\u003c/sup\u003e/m\u003csup\u003e2\u003c/sup\u003e; \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.227). According to the cut-off points presented in EWGSOP2 [\u003cspan\u003e1\u003c/span\u003e], the proportion of patients with sarcopenia based on generalized sarcopenia measurements was 49.3% in group A, which was lower than 53.3% in group B, but there was no statistically significant difference (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.828) (Table\u0026nbsp;\u003cspan\u003e3\u003c/span\u003e).\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eTable 2. Paraspinal Muscle Quality\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariable\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eGroup A\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n=71)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eGroup B\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n=30)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eP\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;Value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eCSAI (mm\u003csup\u003e2\u003c/sup\u003e/m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1339.29 \u0026plusmn; 238.78\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1245.64 \u0026plusmn; 286.78\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.142\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eCSA/BMI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e143.29 \u0026plusmn; 35.96\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e123.73 \u0026plusmn; 33.42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.032\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eGoutallier classification\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.003\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1 (n (%))\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e21 (29.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e3 (10)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2 (n (%))\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e36 (50.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e13 (43.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e3 (n (%))\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e10 (14.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e9 (30)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e4 (n (%))\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e4 (5.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e5 (16.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003eCSA, cross-sectional area; CSAI, cross-sectional area index; BMI, body mass index\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003cdiv\u003e\n \u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"520\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eTable 3. Generalized Sarcopenia Parameters\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariable\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eGroup A\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n=71)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eGroup B\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n=30)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eP\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;Value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eASMI (kg/m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e5.98 \u0026plusmn; 1.15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e5.79 \u0026plusmn; 1.18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.535\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eASM/BMI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.64 \u0026plusmn; 0.17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.57 \u0026plusmn; 0.15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.126\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eNTPA (mm\u003csup\u003e2\u003c/sup\u003e/m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e785.63 \u0026plusmn; 205.69\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e720.8 \u0026plusmn; 226.91\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.227\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eSarcopenia (n (%))\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e35 (49.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e16 (53.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.828\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003eASM, appendicular skeletal muscle mass; ASMI, appendicular skeletal muscle mass index; BMI, body mass index, NTPA, Normalized total psoas area\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eThe ICC for the NTPA 0.93 (95% CI 0.92\u0026thinsp;\u0026minus;\u0026thinsp;0.94). The ICC for the total CSA and FI (Goutalier classification) of the paraspinal muscle is 0.91 (95% CI 0.90\u0026thinsp;\u0026minus;\u0026thinsp;0.93) and 0.90 (95% CI 0.83\u0026thinsp;\u0026minus;\u0026thinsp;0.97).\u003c/p\u003e\n\u003cp\u003eMultiple logistic regression analysis showed statistically significant predictive factors for failure of conservative treatment. The CSA/BMI (OR: 0.983, 95% CI, 0.968\u0026ndash;0.999, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.037) was only independently associated with failure of conservative treatment in our secondary analysis. Even after adjusting for segmental instability, the CSA/BMI of the paraspinal muscles remained an independent predictor of conservative treatment failure (adjusted OR: 0.982, 95% CI: 0.967\u0026ndash;0.998, p\u0026thinsp;=\u0026thinsp;0.028).\u003c/p\u003e\n\u003cp\u003eASM/BMI demonstrated the highest correlation with CSA/BMI (rho\u0026thinsp;=\u0026thinsp;0.73, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001) among the generalized sarcopenia parameters; the other correlations were statistically significant (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001) but lower in strength (Table\u0026nbsp;\u003cspan\u003e4\u003c/span\u003e). CSA/BMI demonstrated the highest correlation with fatty degeneration of paraspinal muscles (rho = -0.6, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001) among the paraspinal and generalized sarcopenia measurements.\u003c/p\u003e\n\u003cdiv\u003e\n \u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"435\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"3\" valign=\"bottom\"\u003e\n \u003cp\u003e\u003cstrong\u003eTable 4. Results of Correlation Analysis Between CSA/BMI and Generalized Sarcopenia Parameters\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" valign=\"bottom\"\u003e\n \u003cp\u003e\u003cstrong\u003eFactor\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"bottom\"\u003e\n \u003cp\u003e\u003cstrong\u003eCorrelation with CSA/BMI (n = 101)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\"\u003e\n \u003cp\u003e\u003cstrong\u003eCoefficient\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eP\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;Value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eASMI (kg/m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.388\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eASM/BMI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.730\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eNTPA (mm\u003csup\u003e2\u003c/sup\u003e/m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.440\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"3\" valign=\"top\"\u003e\n \u003cp\u003eASM, appendicular skeletal muscle mass; ASMI, appendicular skeletal muscle mass index; BMI, body mass index, NTPA, Normalized total psoas area\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe present study investigates the concordance between various assessment tools for generalized and paraspinal sarcopenia among patients with degenerative LSS and identifies risk factors predicting conservative treatment failure. To the best of our knowledge, this is the first study to investigate the association between sarcopenia and the prognosis of conservative treatment in patients with degenerative spinal diseases. Our findings provide significant insights into the intricate relationship between sarcopenia and LSS, emphasizing the need for distinct diagnostic approaches. This distinction is crucial for the clinical assessment and management of spinal conditions. Recent research supports the idea that spine-specific sarcopenia should be given greater importance in the context of spinal diseases. Schonnagel et al. highlighted that paraspinal muscle atrophy, rather than generalized sarcopenia, significantly impacts functional outcomes and pain levels in patients with spinal disorders [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Similarly, Pinter et al. found that worse paraspinal muscle quality was associated with poorer patient-reported outcomes following spinal surgeries, reinforcing the need for targeted evaluation of paraspinal muscles [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Furthermore, Chang et al. demonstrated that paraspinal lean muscle mass measured via MRI could predict adjacent segment disease after lumbar fusion, suggesting the importance of paraspinal muscle health in postoperative prognosis [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. These findings align with our results, which indicate that better-preserved paraspinal muscle mass and lower fatty degeneration are associated with more favorable outcomes in conservative treatment of lumbar spinal stenosis.\u003c/p\u003e \u003cp\u003eThe results of this study highlight the distinct role of paraspinal sarcopenia in patients with degenerative LSS, differentiating it from generalized sarcopenia. Our findings demonstrate a weak correlation between generalized sarcopenia and the prognosis of LSS, suggesting that generalized and spine-specific sarcopenia may arise from different etiologies. This observation is crucial as it raises concerns about the potential for misdiagnosis when using screening tools designed primarily for generalized sarcopenia in the context of spinal disorders [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan additionalcitationids=\"CR28\" citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe analysis revealed that the CSA and CSA/BMI of the paraspinal muscles were significantly higher in patients who responded well to conservative treatment compared to those who eventually required surgical intervention. This indicates that better-preserved paraspinal muscle mass and lower fatty degeneration are associated with more favorable outcomes in conservative treatment of LSS. Specifically, the CSA/BMI was independently associated with conservative treatment failure, suggesting its potential utility as a predictive marker for treatment outcomes [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan additionalcitationids=\"CR17\" citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan additionalcitationids=\"CR31\" citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. Contrary to the paraspinal measurements, generalized sarcopenia indices such as ASMI, ASM/BMI and NTPA did not show significant differences between the two patient groups. This further supports the notion that paraspinal muscle health might play a more critical role in the management of LSS than generalized muscle mass [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. The lack of significant differences in generalized sarcopenia measurements between successful and failed conservative treatment groups underscores the importance of focusing on paraspinal muscle health in the clinical assessment and management of LSS [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAdditionally, we analyzed the impact of spondylolisthesis and segmental instability on treatment outcomes. Our results showed that while spondylolisthesis was more prevalent in the surgical group (Group B), the difference was not statistically significant (p\u0026thinsp;=\u0026thinsp;0.16). This aligns with previous studies indicating that the natural history of degenerative spondylolisthesis is generally favorable, with only 10\u0026ndash;15% of patients eventually requiring surgery after seeking treatment. Long-term follow-up studies have found that progression of vertebral slippage in non-surgically managed patients does not necessarily correlate with changes in clinical symptoms, supporting our finding that spondylolisthesis may not significantly affect conservative treatment failure [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. In contrast, segmental instability showed a statistically significant association with conservative treatment failure (p\u0026thinsp;=\u0026thinsp;0.03), suggesting that it may contribute to symptom worsening and increase the need for surgical intervention. Therefore, segmental instability should be considered an important factor in predicting the prognosis of conservative treatment.\u003c/p\u003e \u003cp\u003ePrevious studies have emphasized the clinical significance of psoas CSA in spine surgery, demonstrating its correlation with postoperative mortality, adverse events and functional outcomes after surgery [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. However, the results of this study differed from previous research. There was no significant difference in the CSA of the psoas muscle between groups A and B. Additionally, logistic regression analysis did not yield significant results (OR: 0.999, 95% CI, 0.995\u0026ndash;1.002, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.542), and the correlation with CSA/BMI was also low (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e4\u003c/span\u003e). The CSA of the psoas muscle appears to have some utility as an assessment tool for postoperative outcomes and prognosis in spinal surgery patients. However, it seems insufficient as an indicator for evaluating the non-operative patients. Particularly in cases of degenerative spinal diseases, the assessment of the paraspinal muscles provides a more appropriate indicator for sarcopenia compared to the psoas muscle [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. Anatomically, the erector spinae muscles are directly involved in maintaining spinal stability and posture, which are critical in the pathophysiology of spinal degeneration. Unlike the psoas muscle, which primarily functions in hip flexion, the erector spinae muscles bear the brunt of compensatory mechanisms during spinal deterioration. Furthermore, the degeneration of the erector spinae muscles closely correlates with functional impairment and pain in patients, making it a more precise marker for sarcopenia. From a biomechanical perspective, the erector spinae muscles' endurance and strength are pivotal in mitigating the progression of spinal degeneration [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eBased on the results of this study, it is inferred that standardizing muscle CSA measurements using BMI, rather than height squared, would result in greater accuracy in the assessment of sarcopenia. This approach aligns with the latest guidelines from the Asian Working Group for Sarcopenia (AWGS) [\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e]. BMI incorporates both weight and height, providing a more comprehensive reflection of an individual's body composition. This can improve the sensitivity and specificity of CSA measurements in diagnosing sarcopenia. However, there remains ongoing debate regarding the optimal adjustment method and whether a single approach can be universally applied across different populations. Thus, future studies should further investigate the comparative effectiveness of these standardization methods to establish a more precise diagnostic criterion.\u003c/p\u003e \u003cp\u003eThis study has several limitations that need to be considered. Firstly, the retrospective nature of the study design may introduce selection bias, as it relies on previously collected data from medical records. Secondly, we identified patients using the diagnosis code for lumbar spinal stenosis from our hospital's electronic medical records. Over a 10-year period, only 101 patients met our inclusion criteria, which is a relatively small sample size. This number appears limited due to our strict inclusion criteria\u0026mdash;specifically, the requirement that patients had both MRI and DXA examinations within a 6-month interval, had undergone at least 3 months of conservative treatment, and had a minimum of 1-year follow-up data. The stringent criteria may have introduced selection bias and limited the sample size, potentially affecting the generalizability of our findings. Additionally, the study population was drawn from a single institution, which may not represent the broader population. The time interval between MRI and DXA examinations varied, potentially affecting the accuracy of muscle measurements. Another limitation of our study is the use of cross-sectional (2-D) muscle measurements rather than volumetric (3-D) analysis. Volumetric muscle assessment could provide a more accurate and comprehensive evaluation of muscle mass and quality. However, due to the retrospective nature of our study and the limitations of the imaging protocols used, volumetric analysis was not feasible. Future prospective studies employing advanced imaging techniques and standardized protocols for volumetric muscle assessment are needed to further elucidate the relationships between localized muscle volume and systemic muscle mass. Furthermore, we did not account for variations in physical activity levels, nutritional status, or other comorbidities that could impact muscle mass and function. Lastly, the assessment of muscle quality was based on imaging techniques, which may not fully capture the functional aspects of sarcopenia.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn conclusion, this study highlights the distinct role of paraspinal sarcopenia in patients with degenerative LSS, distinguishing it from generalized sarcopenia. The findings indicate a weak correlation between generalized sarcopenia and the prognosis of LSS, suggesting that these conditions may have different etiologies. This underscores the need for tailored diagnostic approaches that consider the unique characteristics of paraspinal sarcopenia. Future research should focus on elucidating these specific etiologies to better inform treatment strategies and improve patient outcomes. Additionally, larger studies with extended follow-up periods are warranted to further investigate these relationships and aid in the development of more precise diagnostic tools.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eAll authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by S.M. and J.W.. The first draft of the manuscript was written by S.M. and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eData availability statements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data that support the findings of this study are not openly available due to reasons of sensitivity and are available from the corresponding author upon reasonable request.\u003c/p\u003e\n"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eCruz-Jentoft AJ, Baeyens JP, Bauer JM, Boirie Y, Cederholm T, Landi F, Martin FC, Michel J-P, Rolland Y, Schneider SM (2010) Sarcopenia: European consensus on definition and diagnosis: Report of the European Working Group on Sarcopenia in Older People. Age and ageing 39:412-423\u003c/li\u003e\n\u003cli\u003eMizutani M, Eguchi Y, Toyoguchi T, Orita S, Inage K, Shiga Y, Maki S, Nakamura J, Hagiwara S, Aoki Y, Inoue M, Koda M, Takahashi H, Akazawa T, Ohtori S (2024) Association between Osteoporosis and Skeletal Muscle Mass in Men. 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Spine (Phila Pa 1976) 45:E1105-E1110. doi: 10.1097/BRS.0000000000003498\u003c/li\u003e\n\u003cli\u003eSchlaeger S, Inhuber S, Rohrmeier A, Dieckmeyer M, Freitag F, Klupp E, Weidlich D, Feuerriegel G, Kreuzpointner F, Schwirtz A, Rummeny EJ, Zimmer C, Kirschke JS, Karampinos DC, Baum T (2019) Association of paraspinal muscle water-fat MRI-based measurements with isometric strength measurements. Eur Radiol 29:599-608. doi: 10.1007/s00330-018-5631-8\u003c/li\u003e\n\u003cli\u003eKitsuda Y, Wada T, Tanishima S, Osaki M, Nagashima H, Hagino H (2023) Impact of Sarcopenia on Spinal Spondylosis: A Literature Review. J Clin Med 12. doi: 10.3390/jcm12165401\u003c/li\u003e\n\u003cli\u003eKalichman L, Hunter DJ (2008) Diagnosis and conservative management of degenerative lumbar spondylolisthesis. Eur Spine J 17:327-335. doi: 10.1007/s00586-007-0543-3\u003c/li\u003e\n\u003cli\u003eLee JC, Cha JG, Kim Y, Kim YI, Shin BJ (2008) Quantitative analysis of back muscle degeneration in the patients with the degenerative lumbar flat back using a digital image analysis: comparison with the normal controls. Spine (Phila Pa 1976) 33:318-325. doi: 10.1097/BRS.0b013e318162458f\u003c/li\u003e\n\u003cli\u003eHu Z-J, Fang X-Q, Fan S-W (2014) Iatrogenic injury to the erector spinae during posterior lumbar spine surgery: underlying anatomical considerations, preventable root causes, and surgical tips and tricks. European Journal of Orthopaedic Surgery \u0026amp; Traumatology 24:127-135\u003c/li\u003e\n\u003cli\u003eYazici A, Yerlikaya T (2022) The relationship between the degeneration and asymmetry of the lumbar multifidus and erector spinae muscles in patients with lumbar disc herniation with and without root compression. Journal of Orthopaedic Surgery and Research 17:541\u003c/li\u003e\n\u003cli\u003eOchi M, Kohara K, Tabara Y, Kido T, Uetani E, Ochi N, Igase M, Miki T (2010) Arterial stiffness is associated with low thigh muscle mass in middle-aged to elderly men. Atherosclerosis 212:327-332\u003c/li\u003e\n\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":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-5400496/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5400496/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003ePurpose\u003c/h2\u003e \u003cp\u003eTo evaluate the concordance between assessment tools for generalized and paraspinal sarcopenia in patients with degenerative spinal stenosis, and to identify risk factors associated with conservative treatment failure and poor prognosis.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eWe retrospectively reviewed 101 patients with degenerative lumbar spinal stenosis who underwent MRI/whole-body DXA and at least three months of conservative treatment between 2013 and 2023. Patients were divided into two groups: 71 patients who continued with conservative treatment (Group A) and 30 patients who underwent surgery after conservative treatment failure (Group B). The decision to proceed with surgery was based on persistent or worsening symptoms despite comprehensive conservative management, and the surgical procedures performed included posterior decompressive laminectomy, with or without spinal fusion. Two independent reviewers assessed paraspinal and psoas muscle quality using axial T2 MRI. Paraspinal sarcopenia was determined by cross-sectional area (CSA) and the Goutalier classification of the paralumbar (PL) multifidus and erector spinae muscles. Generalized sarcopenia was assessed by normalized total psoas area (NTPA) and appendicular skeletal muscle mass (ASM) values by DXA. Patients were divided into two groups based on conservative treatment success or failure, and characteristics were compared using the Student t-test and chi-squared test. Logistic regression generated unadjusted odds ratios (OR) for conservative treatment failure. Spearman\u0026rsquo;s rank correlation coefficient (rho) was used to calculate the correlation between assessments of paraspinal and generalized sarcopenia.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003ePatients who underwent surgery had a lower PL-CSA/BMI and higher fatty infiltration of PL muscles. No significant differences were found in generalized sarcopenia parameters between the groups. PL-CSA/BMI (OR: 0.983, p\u0026thinsp;=\u0026thinsp;0.037) was independently associated with treatment failure. ASM/BMI had the highest correlation with PL-CSA/BMI (rho\u0026thinsp;=\u0026thinsp;0.73, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), though other correlations were significant but weaker.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eOur study highlights the distinct role of paraspinal sarcopenia in degenerative lumbar spinal stenosis, showing a weak correlation with generalized sarcopenia. Paraspinal muscle health is crucial for predicting conservative treatment outcomes, emphasizing the need for specific diagnostic approaches. Future research should refine diagnostic criteria to improve patient management and outcomes.\u003c/p\u003e","manuscriptTitle":"The Impact of Paraspinal Sarcopenia Compared to Generalized Sarcopenia on Conservative Treatment Outcomes in Degenerative Lumbar Spinal Stenosis","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-12-18 16:50:36","doi":"10.21203/rs.3.rs-5400496/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"5ad59042-5a26-4e7e-b71c-e3d897793785","owner":[],"postedDate":"December 18th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-11-20T18:40:36+00:00","versionOfRecord":{"articleIdentity":"rs-5400496","link":"https://doi.org/10.1097/BSD.0000000000001945","journal":{"identity":"clinical-spine-surgery","isVorOnly":true,"title":"Clinical Spine Surgery"},"publishedOn":"2025-10-08 00:00:00","publishedOnDateReadable":"October 8th, 2025"},"versionCreatedAt":"2024-12-18 16:50:36","video":"","vorDoi":"10.1097/BSD.0000000000001945","vorDoiUrl":"https://doi.org/10.1097/BSD.0000000000001945","workflowStages":[]},"version":"v1","identity":"rs-5400496","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5400496","identity":"rs-5400496","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}