Validity and accuracy of Swespine data on surgery for central lumbar spinal stenosis and lumbar disc herniation: A Cohort Study of 796 Patients

Validity and accuracy of Swespine data on surgery for central lumbar spinal stenosis and lumbar disc herniation: A Cohort Study of 796 Patients | 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 Validity and accuracy of Swespine data on surgery for central lumbar spinal stenosis and lumbar disc herniation: A Cohort Study of 796 Patients Gustav Wegdell, Abdulrahman Albarni, Josefin Åkerstedt, Peter Endler, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6597094/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 12 Jun, 2025 Read the published version in European Spine Journal → Version 1 posted 9 You are reading this latest preprint version Abstract Purpose: To validate the Swedish National Spine Registry (Swespine) for diagnostic accuracy and documentation of surgical procedures for central lumbar spinal stenosis (CLSS) and lumbar disc herniation (LDH), including an analysis of preoperative magnetic resonance imaging (MRI). Additionally, this study evaluates the accuracy and completeness of perioperative data and documented complications. Methods: Of 41,312 patients registered in Swespine for CLSS or LDH between January 2017 and December 2022, 800 were randomly selected from four hospitals. The electronic patient records were used as the gold standard. Radiological criteria for CLSS and LDH were established through a review of MRI scans. Results: The proportion of correctly classified diagnoses (PCC) was 98.5% for CLSS and 99.2% for LDH, while the PCC of the type of surgery was 99.7% and 98.5% in the CLSS and LDH cohorts, respectively. Preoperative MRI analysis showed that 94.2% of patients undergoing CLSS surgery at the narrowest spinal level were classified as Schizas C or D, with a mean cross-sectional area of 44.2 mm². In comparison, 85.0% of patients who underwent LDH surgery were classified with Pfirrman grade 3. Conclusion: Swespine demonstrated high accuracy and completeness in diagnosing and surgically treating CLSS and LDH patients, as corroborated by preoperative MRI assessments. Most perioperative data, including complications, demonstrated acceptable to excellent registration. Improvements are recommended in the documentation of the American Society of Anaesthesiologistsclassification, patient weight and height, smoking status, use of implants and bone grafts, date of discharge, use of thromboprophylaxis, and previous surgeries. Swespine Lumbar spinal stenosis Lumbar disc herniation Validity Accuracy Figures Figure 1 Introduction Spine surgery registries provide the foundation for population-based research, and high-quality registries represent a cost-effective resource for quality improvement and clinical research [ 1 ]. A national registry featuring prospectively gathered, comprehensive, and highly complete data can be a valuable adjunct to randomised controlled trials (RCTs), provided the data's reliability and quality are assured [ 1 ]. While global spine registries amass considerable data, research evaluating data accuracy remains limited, and previous studies' conclusions on data validity are inconsistent. Analysis of the Norwegian Spine Registry (Norspine) revealed strong agreement for several perioperative variables, but weak agreement for perioperative complications [ 2 ]. In opposition, a German spine registry validation study identified substantial inaccuracies, cautioning against using registry data to avoid erroneous conclusions [ 3 ]. The Swedish National Spine Registry (Swespine) has only been validated in two studies. Endler et al. found that the accuracy for diagnosing isthmic spondylolisthesis was 97%, and perioperative complications such as dural tears were under-reported [ 4 ]. In another study, Charalampidis et al. reported a high accuracy for diagnosing scoliosis registered in Swespine [ 5 ]. However, validation of the data in Swespine was not the main purpose of the earlier studies. Preoperative spinal magnetic resonance imaging (MRI) can validate clinical findings suggestive of central lumbar spinal stenosis (CLSS) and lumbar disc herniation (LDH). MRI is therefore vital to the planning of surgical intervention. Nevertheless, these findings are rarely described in registry-based studies [ 1 ]. Although radiological findings are not always consistent with clinical symptoms or postoperative outcome, their inclusion in the study provides supplementary diagnostic confirmation. This study sought to verify the recorded diagnoses and surgical procedures for CLSS and LDH within the Swespine cohort and to describe the corresponding preoperative radiological findings for each diagnosis. A secondary aim was to investigate the accuracy and completeness of perioperative data, focusing on the documentation of perioperative complications. Patients and methods Study design and setting This retrospective study complied with the ethical principles of the Helsinki Declaration and was approved by the Swedish Ethical Review Authority (registration number 2023-00237-01). The datasets used in this study are not publicly available due to patient integrity but are available to the corresponding author upon reasonable request. A unique personal identification number (PIN) is assigned to all Swedish permanent residents, enabling data linkage between the Swespine database and electronic patient records (EPRs) [6]. The dataset included information from Swespine, using EPRs as the gold standard (GS) for validation. Swespine Swespine is the Swedish National Register for Spine Surgery [7, 8]. The estimated coverage is 95%, while the registered operations exhibit approximately 85% completeness. The register collects data through preoperative and postoperative follow-up questionnaires at 1, 2, and 5 years after surgery. Preoperative patient-reported data include age, sex, smoking status, analgesics (regular use, intermittent, or none), weight, height, back and leg pain intensity, walking ability, symptom duration, EuroQol 5 Dimensions (EQ-5D), and Oswestry disability Index (ODI) scores. The surgeon records surgical data, including diagnosis, type of surgery, use of implants and/or bone grafting, number of levels and side operated, use of prophylaxis (antibiotic- and/or thromboprophylaxis), peri- and post-operative complications, and the American Society of Anaesthesiologists (ASA) classification. Variables The items analysed per case included variables from the surgical report, including diagnosis, surgery type, surgery date, discharge date, side of surgery, surgical level, implant use, bone grafting, antibiotic- and thromboprophylaxis, acute/elective surgery, perioperative complications, reoperation date, indication for reoperation, reoperation type and ASA classification. Preoperative data included validated variables of height, weight, and smoking status (binary: yes/no). Patients and methods The study included 5,764 patients registered in Swespine who underwent surgical intervention for CLSS or LDH between January 1, 2017, and December 31, 2022. Patients were recruited from four institutions: two university hospitals, one regional hospital, and one private hospital. A random sample of 100 patients from each hospital was selected for each diagnosis (CLSS and LDH), and their EPRs were reviewed. A flowchart illustrating the inclusion process is presented in Figure 1. The EPRs reviewed consisted of each patient’s preoperative questionnaire, a self-reported health declaration, the surgeon's operative report, and the anaesthesiologist's anaesthesia report. A retrospective analysis of patients' preoperative MRI scans was conducted to assess radiological criteria for surgical intervention for CLSS and LDH. For CLSS, the Schizas classification (SchC) [9] and the spinal canal area measurements were used [10]. For LDH, the Pfirrman classification (PfiC) was applied [11]. A sensitivity analysis of the inter-observer agreement for the SchC and PfiC, was performed. For SchC, the first (GW) and last author (BK) independently observed the first 50 cases of CLSS collected from the private hospital (SchC dichotomised into A+B or C+D). For the PfiC, the agreement between the PfiC of the first author and PfiC of the radiologist report was analysed for 220 MRI scans. Statistics The proportion of correctly recorded diagnoses, surgical procedures, and perioperative variables in Swespine is reported as numbers and percentages. The descriptive analysis of the radiological examination and assessment criteria is shown using numbers and percentages. Sensitivity analysis involved calculating percentage agreement by dividing instances of rater concordance by the total number of ratings or observations. Inter-observer reliability was determined via calculation of Cohen's kappa (κ) [12]. Precision of the estimates The primary sample size calculation included 400 patients with CLSS and 400 with LDH. The significance level was set at 0.05. Assuming a proportion of correctly recorded diagnoses between 0.95 and 0.99, the confidence interval (CI) ranged from ±0.02 to ±0.01. Data were sorted and analysed using IBM SPSS Statistics version 28.0. Results Demographics Data analysis included 796 EPRs, of which 398 belonged to the CLSS group and 398 to the LDH group. The mean age of patients who underwent surgery for CLSS was 68.2 (SD 9.8) years, with 195 (49.1%) identifying as female. Some 40 (13.8%) patients had undergone previous surgery, and 41 (10.3%) patients had perioperative complications. A comparison of these patients with those who underwent surgery for CLSS in Sweden during the study period is shown in Table 1. The mean age of patients who underwent surgery for LDH was 43.2 (SD 12.5) years, with female representation at 44.3% (n=176). In the LDH cohort, 29 (12.1%) patients had undergone previous surgery, while 12 (3.0%) presented with perioperative complications. Table 1 details a comparison of these patient characteristics with those of other patients who underwent LDH surgery during the study period. Accuracy and completeness for diagnosis and surgical treatment The proportion of correctly classified diagnoses (PCC) was 98.5% for CLSS and 99.2% for LDH. The surgical reports of six patients in the CLSS group indicated lateral lumbar spinal stenosis (LLSS), consistent with ICD-10 diagnostic criteria, and these cases were subsequently documented in the Swespine registry as CLSS. In the LDH group, the surgical report indicated two patients with LLSS and one with lumbago with ischias; however, the Swespine registry listed all three as lumbar disc herniation. The PCC for type of surgery was 99.7% in the CLSS cohort and 98.5% in the LDH and cohort. One operation in the CLSS group was registered in Swespine as a decompression operation but was diagnosed with an LDH operation in the surgical report. In the LDH group, two cases initially classified as LDH operations were subsequently identified as decompression operations in the surgical reports; conversely, four patients registered in the Swespine database as decompression operations received diagnoses of LDH operations procedures in their respective surgical reports. Completeness for type of surgery was 98.2% for the CLSS group and 98.7% for the LDH group. Accuracy and completeness of perioperative data Date of surgery, level of surgery, sex and perioperative complications showed both a high PCC and completeness in both the CLSS and LDH cohorts. Most of the remaining variables demonstrated a high PCC (>95%) in the CLSS cohort, except for date of discharge (94.6%), height (93.9%), weight (83.6%) and ASA-grade (78.1%). Thromboprophylaxis (89.8%), indication for reoperation (94.5%), weight (87.3%) and ASA (74.3%) showed lower PCC (<95%) in the LDH cohort. The completeness of the CLSS and LDH cohorts for perioperative complications (100%, respectively 99.7%), indication for reoperation (97.5%, respectively 96.1%), and type of reoperation (98.0%, respectively 96.7%) was high. Conversely, the datasets for weight (67.6%, respectively 51.3%), height (70.1%, respectively 53.0%), and smoking (71.6%, respectively 58.3%) showed low completeness, indicating substantial missing data. Tables 2 and 3 summarise the accuracy and completeness of the data. Preoperative radiological examination The analysis included 344 MRIs from the CLSS cohort and 339 from the LDH cohort. In 324/344 (94.2%) CLSS patients, the narrowest stenosis level was classified as Schizas C or D, with a mean cross-sectional area of 44.2 mm². The agreement between the first and last author on the SchC was 96.0%, and the k value was 0.485 (95% CI, -0.115 – 1.084). The results from the measures on CLSS are shown in Table 4. Most patients who underwent surgery for LDH were classified with Pfirrman grade 3 (85.0%, 288/339), followed by 13.0% (44/339) with Pfirrman grade 2, and 2.0% with Pfirrman grade 1. The agreement between the first author and the radiologist was 98.2%, and the k value was 0.956 (95% CI, 0.905-1.006). Discussion This study is the first to focus on validating data from Swespine. The main finding was a high diagnostic and surgical accuracy for CLSS/LDH patients in the Swespine registry, using EPRs as the GS. Most patients who underwent surgical intervention for CLSS were graded as Schizas C or D. A significant number of LDH patients displayed preoperative MRI evidence of nerve root deviation or compression, corroborating the diagnosis. Moreover, the registration of perioperative complications showed both high accuracy and completeness. The variables demonstrated acceptable (≥ 90%) to excellent accuracy (≥ 95%), except for ASA class and weight registration. Weight and height data, gathered at varying times in Swespine and the EPRs, may account for the reduced accuracy of these variables. The absence of complete data for ASA class, smoking status, patient weight, height, and antibiotic prophylaxis warrants improvement in the registration procedure. Consistent with previous studies using the Swespine and Norspine registries, we observed a high level of accuracy in reporting diagnostic and procedural data. In a study on outcomes after surgery for isthmic spondylolisthesis, Endler et al. found that the accuracy for diagnosing isthmic spondylolisthesis in Swespine was 97% [ 4 ]. In another study from Swespine, Charalampidis et al. investigated the pedicle screw density in scoliosis surgery and found that only 4/627 (0.6%) of patients were misdiagnosed. The final analysis included 328 patients who had undergone posterior fusion surgery for scoliosis; this was confirmed via pre- and post-operative radiological studies, thereby indirectly confirming the diagnosis and surgical intervention [ 5 ]. Consistent with our findings, a Norspine study reported 100% diagnostic accuracy and a strong inter-rater agreement for surgical type [ 2 ]. Conversely, Meyer et al. observed a high degree of inaccuracy in a local German spine registry [ 3 ], largely attributed to low coverage and data completeness. The national scope and high coverage of both Swespine and Norspine may account for the observed discrepancies in the results. The registration of perioperative complications demonstrated high accuracy and completeness in this study, contrasting with previous findings on spine registries. Endler et al. noted that complications were under-reported in Swespine on surgical treatment for isthmic spondylolisthesis. Moreover, Alhaug et al. reported weak inter-rater agreement for perioperative complications in Norspine [ 2 ], and Meyer et al. determined that the German Spine Society registry captured only approximately half of all complications [ 3 ]. Although the reported complication rate in our study is encouraging, establishing a definitive aetiology is challenging given the retrospective nature of the design. However, the possibility exists that the Swedish surgeons' results were affected by previous studies, leading to more accurate documentation of complications. In addition, financial incentives may play a role, as several clinics' compensation models for spine surgery in Sweden include registration in Swespine. Strengths and limitations The study's chief strength lies in its data collection methods. The Swedish PIN enables linking between Swespine and the EPRs. Moreover, the legal mandate for maintaining medical records renders them a necessary source for mandatory variables, including diagnosis and the type of surgery performed. The study's main limitation is the absence of certain medical records variables and the limited completeness and accuracy of a few specific variables within Swespine. A further limitation pertains to variables such as smoking status, where data accuracy within records is questionable. Furthermore, despite exhaustive attempts, the missing MRI data could not be obtained from hospital records. However, 86% of MRI scans were analysed and showed a high inter-rater reliability. While the absence of certain MRI scans may introduce minor variability in the estimations, it does not compromise the generalisability of our findings. The missing covariates mainly reduce the precision of study estimates, and several models have been proposed to compensate for missing data. The completeness of variables within the spine registry is critical to data quality [ 1 , 13 ]. The present study identified several variables requiring improved accuracy and completeness. Swedish legislation and the Swedish PIN enable linking with other national registries, which can improve selected variables within Swespine, including the ASA class, smoking status, patient weight and height and antibiotic prophylaxis could be improved through data sharing with the Swedish Perioperative Registry [ 14 ]. Another possibility is the automatic transfer of data from EPRs to the registry, thereby enhancing registry completeness and validity [ 15 ]. Completion of selected variables should be mandatory, and registration in Swespine should be obligatory for both public and private spine departments, as in the case of Norspine [ 2 ]. Conclusion Swespine demonstrated high accuracy in registering diagnoses and surgical procedures for patients with CLSS or LDH. The preponderance of CLSS patients undergoing surgical intervention was classified as Schizas grade C or D, with a large number of LDH patients exhibiting preoperative MRI evidence of nerve root deviation or compression. The Swespine registry was found to maintain accurate and complete records of perioperative complications. Nevertheless, improvements are recommended for registering ASA classification, patient weight and height, smoking status, use of implants and bone grafts, discharge date, thromboprophylaxis administration, and history of previous surgeries. Declarations Author Contribution All authors conceived the study, contributed to the study’s design, interpretation of the data, and manuscript revision. GW and BK analyzed the data, and GW drafted the manuscript. All authors had full access to all data in the study and took responsibility for the integrity of the data and the accuracy of the analysis. GW is the guarantor. All authors approved the final manuscript. Acknowledgement Funding was provided in part by the Department of Research and Development, Västernorrland County Council, and in part by the Visare Norr Fund and the Emil Andersson foundation for clinical research. 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J Bone Jt Surg Am 99:743–752. https://doi.org/10.2106/jbjs.16.00679 Charalampidis A, Möller A, Wretling ML, et al (2018) Implant density is not related to patient-reported outcome in the surgical treatment of patients with idiopathic scoliosis. Bone Jt J 100-b:1080–1086. https://doi.org/10.1302/0301-620x.100b8.Bjj-2017-1114.R1 Ludvigsson JF, Otterblad-Olausson P, Pettersson BU, Ekbom A (2009) The Swedish personal identity number: possibilities and pitfalls in healthcare and medical research. Eur J Epidemiol 24:659–667. https://doi.org/10.1007/s10654-009-9350-y Strömqvist B, Fritzell P, Hägg O, et al (2013) Swespine: the Swedish spine register : the 2012 report. Eur Spine J 22:953–74. https://doi.org/10.1007/s00586-013-2758-9 Annual report - Swespine. https://swespine.se/page.aspx?id=12&lang=1. Accessed 1 May 2025 Schizas C, Theumann N, Burn A, et al (2010) Qualitative grading of severity of lumbar spinal stenosis based on the morphology of the dural sac on magnetic resonance images. Spine Phila Pa 1976 35:1919–24. https://doi.org/10.1097/BRS.0b013e3181d359bd Andreisek G, Deyo RA, Jarvik JG, et al (2014) Consensus conference on core radiological parameters to describe lumbar stenosis - an initiative for structured reporting. Eur Radiol 24:3224–32. https://doi.org/10.1007/s00330-014-3346-z Pfirrmann CW, Dora C, Schmid MR, et al (2004) MR image-based grading of lumbar nerve root compromise due to disk herniation: reliability study with surgical correlation. Radiology 230:583–8. https://doi.org/10.1148/radiol.2302021289 Viera AJ, Garrett JM (2005) Understanding interobserver agreement: the kappa statistic. Fam Med 37:360–363 Wood AM, White IR, Thompson SG (2004) Are missing outcome data adequately handled? A review of published randomized controlled trials in major medical journals. Clin Trials Lond Engl 1:368–376. https://doi.org/10.1191/1740774504cn032oa Holmström B, Enlund G, Spetz P, Frostell C (2023) The Swedish Perioperative Register: Description, validation of data mapping and utility. Acta Anaesthesiol Scand 67:233–239. https://doi.org/10.1111/aas.14174 Tian Q, Liu M, Min L, et al (2019) An automated data verification approach for improving data quality in a clinical registry. Comput Methods Programs Biomed 181:104840. https://doi.org/10.1016/j.cmpb.2019.01.012 Tables Table 1. Patient characteristics of the study population compared to those of other hospitals from 2017 to 2022. Data are presented as means and standard deviation [ SD ] or numbers (n) and per cent (%). Study cohort CLSS (n=398) Swespine CLSS (n=25,683) Study cohort LDH (n=398) Swespine LDH (n=11,752) Age Missing data 68.2 [9.8] 0 (0.0) 68.3 [10.3] 0 (0.0) 43.2 [12.5] 0 (0.0) 44.7 [13.7] 0 (0) Female Missing data 195 (49.1) 1 (0.3) 13,464 (52.4) 5 (0.0) 176 (44.3) 1 (0.3) 5,169 (44.0) 7 (0.1) BMI* Missing data 28.1 [4.2] 127 (31.9) 28.0 [22.4] 5,308 (20.7) 26.8 [4.4] 167 (42.0) 26.9 [20.4] 3,209 (27.3) Smoking Missing data 13 (4.5) 106 (26.6) 1,068 (4.9) 4,096 (15.9) 19 (8.0) 161 (40.5) 785 (8.8) 2,875 (24.5) ASA** 1 and 2 Missing data 202 (74.0) 125 (31.4) 18,315 (76.5) 1,742 (6.8) 274 (96.5) 114 (28.6) 10,184 (94.6) 993 (8.4) Elective surgery Missing data 374 (95.2) 5 (1.3) 24,925 (98.1) 288 (1.1) 317 (81.9) 11 (2.8) 10,635 (92.0) 194 (1.7) Previous surgeries Missing data 40 (13.8) 109 (27.4) 3,838 (17.8) 4,118 (16.0) 29 (12.1) 158 (40.0) 1,003 (11.3) 2,842 (24.2) Preoperative ODI*** Missing data 43.9 [15.8] 113 (28.4) 43.1 [16.05] 5,249 (20.4) 50.3 [19.0] 160 (40.2) 48.3 [18.1] 3,360 (27.7) Preoperative EQ-5D**** Missing data 0.32 [0.32] 115 (28.9) 0.36 [0.32] 5,425 (20.4) 0.21 [0.32] 160 (40.2) 0.25 [0.34] 3,360 (27.7) Surgery with implant Missing data 21 (7.3) 112 (28.1) 2,098 (12.8) 9,332 (36.3) 4 (1.4) 103 (25.9) 208 (2.9) 4,617 (39.3) Perioperative complications Missing data 41 (10.3) 0 (0.0) 1,874 (7.5) 846 (3.3) 12 (3.0) 1 (0.3) 351 (3.1) 311 (2.6) *BMI: Body mass index **ASA – American Society of Anaesthesiologists – classification of physical status ***ODI: Oswestry Disability Index ****EQ-5D: EuroQol 5 Dimensions (EQ-5D) Table 2. Accuracy and concordance of 398 patients registered in Swespine for surgery for lumbar spinal stenosis (CLSS) using electronic patient records (EPRs) as a reference. Frequency*, n (%) Missing data Swespine, n (%) Missing data EPRs**, n (%) Proportion correctly classified, PCC*** (%) Diagnosis 398 (100) - - 98.5 Type of surgery 391 (98.2) 7 (1.8) - 99.7 Date of surgery 398 (100) - - 98.0 Date of discharge 367 (92.2) 31 (7.8) - 94.6 Side of surgery 360 (90.5) 38 (9.5) - 99.7 Level of surgery 396 (99.5) 2 (0.5) - 96.7 Surgery with implant 286 (71.9) 112 (28.1) - 100 Bone grafting 341 (85.7) 57 (14.3) - 99.4 Antibiotic prophylaxis 345 (86.7) 19 (4.8) 34 100 Thromboprophylaxis 328 (89.8) 56 (14.1) 14 98.2 Acute/elective operation 393 (98.7) 5 (1.3) - 99.5 Perioperative complications 398 (100) - - 97.0 Indication for reoperation 388 (97.5) - 10 99.5 Type of reoperation 390 (98.0) - 8 99.0 Date of reoperation 390 (98.0) - 8 98.5 Sex 397 (99.7) 1 (0.3) - 100 Height 279 (70.1) 110 (27.6) 9 93.9 Weight 269 (67.6) 120 (30.2) 9 83.6 Smoking 285 (71.6) 106 (26.6) 7 99.3 ASA 265 (66.6) 125 (31.4) 8 78.1 *Frequency in Swespine minus the number of patients with missing data in the EPRs for a specific variable **Not verifiable information due to missing data in the EPRs ***Correctly registered data divided by verifiable cases Table 3. Accuracy and concordance of data for 398 patients with lumbar disc herniation (LDH) registered in the Swespine surgical database, using electronic patient records (EPRs) as a reference. Frequency*, n (%) Missing data Swespine, n (%) Missing data EPRs**, n (%) Proportion correctly classified***, PCC (%) Diagnosis 398 (100) - - 99.2 Type of surgery 393 (98.7) 5 (1.3) - 98.5 Date of surgery 398 (100) - - 97.7 Date of discharge 334 (83.4) 64 (16.1) - 96.7 Side of surgery 380 (95.5) 18 (4.5) - 97.1 Level of surgery 397 (99.7) 1 (0.3) - 97.5 Surgery with implant 295 (74.1) 103 (25.9) - 99.7 Bone grafting 329 (82.7) 69 (17.3) - 100 Antibiotic prophylaxis 321 (80.7) 23 (5.8) 54 99.1 Thromboprophylaxis 332 (83.4) 55 (13.8) 11 89.8 Acute/elective operation 387 (97.2) 11 (2.8) - 97.9 Perioperative complications 397 (99.7) 1 (0.3) - 98.0 Indication for reoperation 384 (96.1) 7 (1.8) 7 94.5 Type of reoperation 385 (96.7) 7 (1.8) 6 97.7 Date of reoperation 384 (96.1) 7 (1.8) 7 97.4 Sex 397 (99.7) 1 (0.3) - 100 Height 211 (53.0) 160 (40.2) 27 95.7 Weight 204 (51.3) 167 (42.0) 27 87.3 Smoking 232 (58.3) 161 (40.5) 5 98.7 ASA 253 (70.0) 114 (28.6) 31 74.3 *Frequency in Swespine minus the number of patients with missing data in the EPRs for a specific variable **Not verifiable information due to missing data in the EPRs ***Correctly registered data divided by verifiable cases Table 4. Characterization of magnetic resonance ( MR) images of 344 patients registered in Swespine for lumbar spinal stenosis (CLSS) surgery. Level 1 Level 2 Level 3 Schizas, n (%) n=344 n=142 n=38 A 2 (0.6) 1 (0.7) 2 (5.3) B 18 (5.2) 34 (23.9) 12 (31.6) C 169 (49.1) 71 (50.0) 15 (39.5) D 155 (45.1) 36 (25.4) 9 (23.7) Area* (mm 2 ), mean (95% CI) 44.2 (42.2-46.1) 62.5 (56.7-68.4) 72.2 (58.9-85.5) CI: Confidence interval * A radiologist measured the area in 52% of patients; the first author (GW) measured the area in the remaining 48%. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 12 Jun, 2025 Read the published version in European Spine Journal → Version 1 posted Editorial decision: Revision requested 24 May, 2025 Reviews received at journal 21 May, 2025 Reviews received at journal 16 May, 2025 Reviewers agreed at journal 15 May, 2025 Reviewers agreed at journal 14 May, 2025 Reviewers invited by journal 14 May, 2025 Editor assigned by journal 12 May, 2025 Submission checks completed at journal 12 May, 2025 First submitted to journal 05 May, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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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-6597094","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":457492675,"identity":"15a89219-8149-4301-a58d-925c6aa1895a","order_by":0,"name":"Gustav Wegdell","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA6klEQVRIiWNgGAWjYJADA4YHBTZEqWRsgGtJMEgjXcthwurlI9KfP/jZxpDYz79444MEg/OJa2ckMH/4gEeL4Y0cw8ZeoJaZM54VGyQY3E7cdiOBTXIGPi0zchgbeM4w5G64ccZMAqaFmQevlvSHjX+AWvbfOGP+I8HgHEgL8+c/+PwikWDYzFMBtIW/xwzo/QMgLQzS+LxvwPPGcLZMhUT9jBtsxUCHJRtvO/OwTbIHny3t6Q8+vjGwMebvP7zxw4cKO9ltx5MPf/iBz5YDYEoCiBJgYvCIwmELXJr/AF6Fo2AUjIJRMIIBAPFxVqRkTVR4AAAAAElFTkSuQmCC","orcid":"","institution":"Department of Diagnostics and Intervention, Umeå University","correspondingAuthor":true,"prefix":"","firstName":"Gustav","middleName":"","lastName":"Wegdell","suffix":""},{"id":457492676,"identity":"9b82d72f-e137-4244-9257-2b027ada8ea7","order_by":1,"name":"Abdulrahman Albarni","email":"","orcid":"","institution":"Department of Diagnostics and Intervention, Umeå University","correspondingAuthor":false,"prefix":"","firstName":"Abdulrahman","middleName":"","lastName":"Albarni","suffix":""},{"id":457492677,"identity":"36cab6a8-7c84-4897-989a-4d8c9b9a3893","order_by":2,"name":"Josefin Åkerstedt","email":"","orcid":"","institution":"Department of Diagnostics and Intervention, Umeå University","correspondingAuthor":false,"prefix":"","firstName":"Josefin","middleName":"","lastName":"Åkerstedt","suffix":""},{"id":457492678,"identity":"e77fb8ed-9e13-4af0-a0d9-4f9c4fcdd4a5","order_by":3,"name":"Peter Endler","email":"","orcid":"","institution":"RKC Spine Center, Södra Fiskartorpsvägen 15H, 11433 Stockholm","correspondingAuthor":false,"prefix":"","firstName":"Peter","middleName":"","lastName":"Endler","suffix":""},{"id":457492679,"identity":"50eb345e-d74e-44f5-be55-e65107da729f","order_by":4,"name":"Paul Gerdhem","email":"","orcid":"","institution":"Department of Surgical Sciences, Uppsala University","correspondingAuthor":false,"prefix":"","firstName":"Paul","middleName":"","lastName":"Gerdhem","suffix":""},{"id":457492680,"identity":"4b668086-35c0-4a74-b0ff-a013d62ac55e","order_by":5,"name":"Anders Själander","email":"","orcid":"","institution":"Department of Public Health and Clinical Medicine, Umeå University","correspondingAuthor":false,"prefix":"","firstName":"Anders","middleName":"","lastName":"Själander","suffix":""},{"id":457492681,"identity":"d91b0e4e-fb25-4761-8e7d-a2340ec6906a","order_by":6,"name":"Sebastian Mukka","email":"","orcid":"","institution":"Department of Diagnostics and Intervention, Umeå University","correspondingAuthor":false,"prefix":"","firstName":"Sebastian","middleName":"","lastName":"Mukka","suffix":""},{"id":457492682,"identity":"02515f43-5602-4d73-8a6f-0695afa7bfeb","order_by":7,"name":"Björn Knutsson","email":"","orcid":"","institution":"Department of Diagnostics and Intervention, Umeå University","correspondingAuthor":false,"prefix":"","firstName":"Björn","middleName":"","lastName":"Knutsson","suffix":""}],"badges":[],"createdAt":"2025-05-05 19:53:28","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6597094/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6597094/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00586-025-09049-8","type":"published","date":"2025-06-12T15:57:13+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":83124926,"identity":"46b1157f-8c29-4544-902b-29750956d220","added_by":"auto","created_at":"2025-05-20 09:36:49","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":256255,"visible":true,"origin":"","legend":"\u003cp\u003eSee image above for figure legend.\u003c/p\u003e","description":"","filename":"Figure1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6597094/v1/ace0532ecd5d8c533d61ead9.jpg"},{"id":84726482,"identity":"a4236c0b-e229-437e-863d-fb42fb04221e","added_by":"auto","created_at":"2025-06-16 16:05:34","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1712510,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6597094/v1/ececcc1a-b3c3-46a3-ba51-cfe1957abe85.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Validity and accuracy of Swespine data on surgery for central lumbar spinal stenosis and lumbar disc herniation: A Cohort Study of 796 Patients","fulltext":[{"header":"Introduction","content":"\u003cp\u003eSpine surgery registries provide the foundation for population-based research, and high-quality registries represent a cost-effective resource for quality improvement and clinical research [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. A national registry featuring prospectively gathered, comprehensive, and highly complete data can be a valuable adjunct to randomised controlled trials (RCTs), provided the data's reliability and quality are assured [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. While global spine registries amass considerable data, research evaluating data accuracy remains limited, and previous studies' conclusions on data validity are inconsistent. Analysis of the Norwegian Spine Registry (Norspine) revealed strong agreement for several perioperative variables, but weak agreement for perioperative complications [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. In opposition, a German spine registry validation study identified substantial inaccuracies, cautioning against using registry data to avoid erroneous conclusions [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe Swedish National Spine Registry (Swespine) has only been validated in two studies. Endler et al. found that the accuracy for diagnosing isthmic spondylolisthesis was 97%, and perioperative complications such as dural tears were under-reported [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. In another study, Charalampidis et al. reported a high accuracy for diagnosing scoliosis registered in Swespine [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. However, validation of the data in Swespine was not the main purpose of the earlier studies.\u003c/p\u003e \u003cp\u003ePreoperative spinal magnetic resonance imaging (MRI) can validate clinical findings suggestive of central lumbar spinal stenosis (CLSS) and lumbar disc herniation (LDH). MRI is therefore vital to the planning of surgical intervention. Nevertheless, these findings are rarely described in registry-based studies [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Although radiological findings are not always consistent with clinical symptoms or postoperative outcome, their inclusion in the study provides supplementary diagnostic confirmation.\u003c/p\u003e \u003cp\u003eThis study sought to verify the recorded diagnoses and surgical procedures for CLSS and LDH within the Swespine cohort and to describe the corresponding preoperative radiological findings for each diagnosis. A secondary aim was to investigate the accuracy and completeness of perioperative data, focusing on the documentation of perioperative complications.\u003c/p\u003e"},{"header":"Patients and methods","content":"\u003cp\u003e\u003cem\u003eStudy design and setting\u003c/em\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThis retrospective study complied with the ethical principles of the Helsinki Declaration and was approved by the Swedish Ethical Review Authority (registration number 2023-00237-01).\u0026nbsp;The datasets used in this study are not publicly available due to patient integrity but are available to the corresponding author upon reasonable request.\u003c/p\u003e\n\u003cp\u003eA unique personal identification number (PIN) is assigned to all Swedish permanent residents, enabling data linkage between the Swespine database and electronic patient records (EPRs) [6]. The dataset included information from Swespine, using EPRs as the gold standard (GS) for validation.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eSwespine\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eSwespine is the Swedish National Register for Spine Surgery [7, 8]. The estimated coverage is 95%, while the registered operations exhibit approximately 85% completeness. The register collects data through preoperative and postoperative follow-up questionnaires at 1, 2, and 5 years after surgery. Preoperative patient-reported data include age, sex, smoking status, analgesics (regular use, intermittent, or none), weight, height, back and leg pain intensity, walking ability, symptom duration, EuroQol 5 Dimensions (EQ-5D), and Oswestry disability Index (ODI) scores. The surgeon records surgical data, including diagnosis, type of surgery, use of implants and/or bone grafting, number of levels and side operated, use of prophylaxis (antibiotic- and/or thromboprophylaxis), peri- and post-operative complications, and the American Society of Anaesthesiologists (ASA) classification.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eVariables\u0026nbsp;\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe items analysed per case included variables from the surgical report, including diagnosis, surgery type, surgery date, discharge date, side of surgery, surgical level, implant use, bone grafting, antibiotic- and thromboprophylaxis, acute/elective surgery, perioperative complications, reoperation date, indication for reoperation, reoperation type and ASA classification. Preoperative data included validated variables of height, weight, and smoking status (binary: yes/no). \u0026nbsp; \u003cem\u003e\u0026nbsp;\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003ePatients and methods\u003c/em\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe study included 5,764 patients registered in Swespine who underwent surgical intervention for CLSS or LDH between January 1, 2017, and December 31, 2022. Patients were recruited from four institutions: two university hospitals, one regional hospital, and one private hospital. A random sample of 100 patients from each hospital was selected for each diagnosis (CLSS and LDH), and their EPRs were reviewed. A flowchart illustrating the inclusion process is presented in Figure 1.\u003c/p\u003e\n\u003cp\u003eThe EPRs reviewed consisted of each patient\u0026rsquo;s preoperative questionnaire, a self-reported health declaration, the surgeon\u0026apos;s operative report, and the anaesthesiologist\u0026apos;s anaesthesia report.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eA retrospective analysis of patients\u0026apos; preoperative MRI scans was conducted to assess radiological criteria for surgical intervention for CLSS and LDH. For CLSS, the Schizas classification (SchC) [9] and the spinal canal area measurements were used [10]. For LDH, the Pfirrman classification (PfiC) was applied [11]. A sensitivity analysis of the inter-observer agreement for the SchC and PfiC, was performed. For SchC, the first (GW) and last author (BK) independently observed the first 50 cases of CLSS collected from the private hospital (SchC dichotomised into A+B or C+D). For the PfiC, the agreement between the PfiC of the first author and PfiC of the radiologist report was analysed for 220 MRI scans.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eStatistics\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe proportion of correctly recorded diagnoses, surgical procedures, and perioperative variables in Swespine is reported as numbers and percentages. The descriptive analysis of the radiological examination and assessment criteria is shown using numbers and percentages.\u003c/p\u003e\n\u003cp\u003eSensitivity analysis involved calculating percentage agreement by dividing instances of rater concordance by the total number of ratings or observations. Inter-observer reliability was determined via calculation of Cohen\u0026apos;s kappa (\u0026kappa;) [12].\u003c/p\u003e\n\u003cp\u003e\u003cem\u003ePrecision of the estimates\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe primary sample size calculation included 400 patients with CLSS and 400 with LDH. The significance level was set at 0.05. Assuming a proportion of correctly recorded diagnoses between 0.95 and 0.99, the confidence interval (CI) ranged from \u0026plusmn;0.02 to \u0026plusmn;0.01.\u003c/p\u003e\n\u003cp\u003eData were sorted and analysed using IBM SPSS Statistics version 28.0.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cem\u003eDemographics\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eData analysis included 796 EPRs, of which 398 belonged to the CLSS group and 398 to the LDH group.\u003c/p\u003e\n\u003cp\u003eThe mean age of patients who underwent surgery for CLSS was 68.2 (SD 9.8) years, with 195 (49.1%) identifying as female. Some 40 (13.8%) patients had undergone previous surgery, and 41 (10.3%) patients had perioperative complications. A comparison of these patients with those who underwent surgery for CLSS in Sweden during the study period is shown in Table 1.\u003c/p\u003e\n\u003cp\u003eThe mean age of patients who underwent surgery for LDH was 43.2 (SD 12.5) years, with female representation at 44.3% (n=176). In the LDH cohort, 29 (12.1%) patients had undergone previous surgery, while 12 (3.0%) presented with perioperative complications. Table 1 details a comparison of these patient characteristics with those of other patients who underwent LDH surgery during the study period.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eAccuracy and completeness for diagnosis and surgical treatment\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe proportion of correctly classified diagnoses (PCC) was 98.5% for CLSS and 99.2% for LDH. The surgical reports of six patients in the CLSS group indicated lateral lumbar spinal stenosis (LLSS), consistent with ICD-10 diagnostic criteria, and these cases were subsequently documented in the Swespine registry as CLSS. In the LDH group, the surgical report indicated two patients with LLSS and one with lumbago with ischias; however, the Swespine registry listed all three as lumbar disc herniation. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe PCC for type of surgery was 99.7% in the CLSS cohort and 98.5% in the LDH and cohort. One operation in the CLSS group was registered in Swespine as a decompression operation but was diagnosed with an LDH operation in the surgical report. In the LDH group, two cases initially classified as LDH operations were subsequently identified as decompression operations in the surgical reports; conversely, four patients registered in the Swespine database as decompression operations received diagnoses of LDH operations procedures in their respective surgical reports. Completeness for type of surgery was 98.2% for the CLSS group and 98.7% for the LDH group.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eAccuracy and completeness of perioperative data\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eDate of surgery, level of surgery, sex and perioperative complications showed both a high PCC and completeness in both the CLSS and LDH cohorts. Most of the remaining variables demonstrated a high PCC (\u0026gt;95%) in the CLSS cohort, except for date of discharge (94.6%), height (93.9%), weight (83.6%) and ASA-grade (78.1%). Thromboprophylaxis (89.8%), indication for reoperation (94.5%), weight (87.3%) and ASA (74.3%) showed lower PCC (\u0026lt;95%) in the LDH cohort.\u003c/p\u003e\n\u003cp\u003eThe completeness of the CLSS and LDH cohorts for perioperative complications (100%, respectively 99.7%), indication for reoperation (97.5%, respectively 96.1%), and type of reoperation (98.0%, respectively 96.7%) was high. Conversely, the datasets for weight (67.6%, respectively 51.3%), height (70.1%, respectively 53.0%), and smoking (71.6%, respectively 58.3%) showed low completeness, indicating substantial missing data. Tables 2 and 3 summarise the accuracy and completeness of the data. \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003ePreoperative radiological examination\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe analysis included 344 MRIs from the CLSS cohort and 339 from the LDH cohort.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIn 324/344 (94.2%) CLSS patients, the narrowest stenosis level was classified as Schizas C or D, with a mean cross-sectional area of 44.2 mm\u0026sup2;. The agreement between the first and last author on the\u0026nbsp;SchC was 96.0%, and the k\u0026nbsp;value was 0.485 (95% CI, -0.115 \u0026ndash; 1.084). The results from the measures on CLSS are shown in Table 4.\u003c/p\u003e\n\u003cp\u003eMost patients who underwent surgery for LDH were classified with Pfirrman grade 3 (85.0%, 288/339), followed by 13.0% (44/339) with Pfirrman grade 2, and 2.0% with Pfirrman grade 1. The agreement between the first author and the radiologist was 98.2%, and the k value was 0.956 (95% CI, 0.905-1.006).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis study is the first to focus on validating data from Swespine. The main finding was a high diagnostic and surgical accuracy for CLSS/LDH patients in the Swespine registry, using EPRs as the GS. Most patients who underwent surgical intervention for CLSS were graded as Schizas C or D. A significant number of LDH patients displayed preoperative MRI evidence of nerve root deviation or compression, corroborating the diagnosis. Moreover, the registration of perioperative complications showed both high accuracy and completeness.\u003c/p\u003e \u003cp\u003eThe variables demonstrated acceptable (\u0026ge;\u0026thinsp;90%) to excellent accuracy (\u0026ge;\u0026thinsp;95%), except for ASA class and weight registration. Weight and height data, gathered at varying times in Swespine and the EPRs, may account for the reduced accuracy of these variables. The absence of complete data for ASA class, smoking status, patient weight, height, and antibiotic prophylaxis warrants improvement in the registration procedure.\u003c/p\u003e \u003cp\u003eConsistent with previous studies using the Swespine and Norspine registries, we observed a high level of accuracy in reporting diagnostic and procedural data. In a study on outcomes after surgery for isthmic spondylolisthesis, Endler et al. found that the accuracy for diagnosing isthmic spondylolisthesis in Swespine was 97% [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. In another study from Swespine, Charalampidis et al. investigated the pedicle screw density in scoliosis surgery and found that only 4/627 (0.6%) of patients were misdiagnosed. The final analysis included 328 patients who had undergone posterior fusion surgery for scoliosis; this was confirmed via pre- and post-operative radiological studies, thereby indirectly confirming the diagnosis and surgical intervention [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Consistent with our findings, a Norspine study reported 100% diagnostic accuracy and a strong inter-rater agreement for surgical type [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Conversely, Meyer et al. observed a high degree of inaccuracy in a local German spine registry [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e], largely attributed to low coverage and data completeness. The national scope and high coverage of both Swespine and Norspine may account for the observed discrepancies in the results.\u003c/p\u003e \u003cp\u003eThe registration of perioperative complications demonstrated high accuracy and completeness in this study, contrasting with previous findings on spine registries. Endler et al. noted that complications were under-reported in Swespine on surgical treatment for isthmic spondylolisthesis. Moreover, Alhaug et al. reported weak inter-rater agreement for perioperative complications in Norspine [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e], and Meyer et al. determined that the German Spine Society registry captured only approximately half of all complications [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Although the reported complication rate in our study is encouraging, establishing a definitive aetiology is challenging given the retrospective nature of the design. However, the possibility exists that the Swedish surgeons' results were affected by previous studies, leading to more accurate documentation of complications. In addition, financial incentives may play a role, as several clinics' compensation models for spine surgery in Sweden include registration in Swespine.\u003c/p\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003eStrengths and limitations\u003c/h2\u003e \u003cp\u003eThe study's chief strength lies in its data collection methods. The Swedish PIN enables linking between Swespine and the EPRs. Moreover, the legal mandate for maintaining medical records renders them a necessary source for mandatory variables, including diagnosis and the type of surgery performed. The study's main limitation is the absence of certain medical records variables and the limited completeness and accuracy of a few specific variables within Swespine. A further limitation pertains to variables such as smoking status, where data accuracy within records is questionable. Furthermore, despite exhaustive attempts, the missing MRI data could not be obtained from hospital records. However, 86% of MRI scans were analysed and showed a high inter-rater reliability. While the absence of certain MRI scans may introduce minor variability in the estimations, it does not compromise the generalisability of our findings.\u003c/p\u003e \u003cp\u003eThe missing covariates mainly reduce the precision of study estimates, and several models have been proposed to compensate for missing data. The completeness of variables within the spine registry is critical to data quality [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. The present study identified several variables requiring improved accuracy and completeness. Swedish legislation and the Swedish PIN enable linking with other national registries, which can improve selected variables within Swespine, including the ASA class, smoking status, patient weight and height and antibiotic prophylaxis could be improved through data sharing with the Swedish Perioperative Registry [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Another possibility is the automatic transfer of data from EPRs to the registry, thereby enhancing registry completeness and validity [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Completion of selected variables should be mandatory, and registration in Swespine should be obligatory for both public and private spine departments, as in the case of Norspine [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eSwespine demonstrated high accuracy in registering diagnoses and surgical procedures for patients with CLSS or LDH. The preponderance of CLSS patients undergoing surgical intervention was classified as Schizas grade C or D, with a large number of LDH patients exhibiting preoperative MRI evidence of nerve root deviation or compression. The Swespine registry was found to maintain accurate and complete records of perioperative complications. Nevertheless, improvements are recommended for registering ASA classification, patient weight and height, smoking status, use of implants and bone grafts, discharge date, thromboprophylaxis administration, and history of previous surgeries.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eAll authors conceived the study, contributed to the study\u0026rsquo;s design, interpretation of the data, and manuscript revision. GW and BK analyzed the data, and GW drafted the manuscript. All authors had full access to all data in the study and took responsibility for the integrity of the data and the accuracy of the analysis. GW is the guarantor. All authors approved the final manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eFunding was provided in part by the Department of Research and Development, V\u0026auml;sternorrland County Council, and in part by the Visare Norr Fund and the Emil Andersson foundation for clinical research.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eMcGirt MJ, Parker SL, Asher AL, et al (2014) Role of prospective registries in defining the value and effectiveness of spine care. Spine 39:S117-128. https://doi.org/10.1097/BRS.0000000000000552\u003c/li\u003e\n\u003cli\u003eAlhaug OK, Kaur S, Dolatowski F, et al (2022) Accuracy and agreement of national spine register data for 474 patients compared to corresponding electronic patient records. Eur Spine J 31:801\u0026ndash;811. https://doi.org/10.1007/s00586-021-07093-8\u003c/li\u003e\n\u003cli\u003eMeyer B, Shiban E, Albers LE, Krieg SM (2020) Completeness and accuracy of data in spine registries: an independent audit-based study. Eur Spine J 29:1453\u0026ndash;1461. https://doi.org/10.1007/s00586-020-06342-6\u003c/li\u003e\n\u003cli\u003eEndler P, Ekman P, M\u0026ouml;ller H, Gerdhem P (2017) Outcomes of Posterolateral Fusion with and without Instrumentation and of Interbody Fusion for Isthmic Spondylolisthesis: A Prospective Study. J Bone Jt Surg Am 99:743\u0026ndash;752. https://doi.org/10.2106/jbjs.16.00679\u003c/li\u003e\n\u003cli\u003eCharalampidis A, M\u0026ouml;ller A, Wretling ML, et al (2018) Implant density is not related to patient-reported outcome in the surgical treatment of patients with idiopathic scoliosis. Bone Jt J 100-b:1080\u0026ndash;1086. https://doi.org/10.1302/0301-620x.100b8.Bjj-2017-1114.R1\u003c/li\u003e\n\u003cli\u003eLudvigsson JF, Otterblad-Olausson P, Pettersson BU, Ekbom A (2009) The Swedish personal identity number: possibilities and pitfalls in healthcare and medical research. Eur J Epidemiol 24:659\u0026ndash;667. https://doi.org/10.1007/s10654-009-9350-y\u003c/li\u003e\n\u003cli\u003eStr\u0026ouml;mqvist B, Fritzell P, H\u0026auml;gg O, et al (2013) Swespine: the Swedish spine register : the 2012 report. Eur Spine J 22:953\u0026ndash;74. https://doi.org/10.1007/s00586-013-2758-9\u003c/li\u003e\n\u003cli\u003eAnnual report - Swespine. https://swespine.se/page.aspx?id=12\u0026amp;lang=1. Accessed 1 May 2025\u003c/li\u003e\n\u003cli\u003eSchizas C, Theumann N, Burn A, et al (2010) Qualitative grading of severity of lumbar spinal stenosis based on the morphology of the dural sac on magnetic resonance images. Spine Phila Pa 1976 35:1919\u0026ndash;24. https://doi.org/10.1097/BRS.0b013e3181d359bd\u003c/li\u003e\n\u003cli\u003eAndreisek G, Deyo RA, Jarvik JG, et al (2014) Consensus conference on core radiological parameters to describe lumbar stenosis - an initiative for structured reporting. Eur Radiol 24:3224\u0026ndash;32. https://doi.org/10.1007/s00330-014-3346-z\u003c/li\u003e\n\u003cli\u003ePfirrmann CW, Dora C, Schmid MR, et al (2004) MR image-based grading of lumbar nerve root compromise due to disk herniation: reliability study with surgical correlation. Radiology 230:583\u0026ndash;8. https://doi.org/10.1148/radiol.2302021289\u003c/li\u003e\n\u003cli\u003eViera AJ, Garrett JM (2005) Understanding interobserver agreement: the kappa statistic. Fam Med 37:360\u0026ndash;363\u003c/li\u003e\n\u003cli\u003eWood AM, White IR, Thompson SG (2004) Are missing outcome data adequately handled? A review of published randomized controlled trials in major medical journals. Clin Trials Lond Engl 1:368\u0026ndash;376. https://doi.org/10.1191/1740774504cn032oa\u003c/li\u003e\n\u003cli\u003eHolmstr\u0026ouml;m B, Enlund G, Spetz P, Frostell C (2023) The Swedish Perioperative Register: Description, validation of data mapping and utility. Acta Anaesthesiol Scand 67:233\u0026ndash;239. https://doi.org/10.1111/aas.14174\u003c/li\u003e\n\u003cli\u003eTian Q, Liu M, Min L, et al (2019) An automated data verification approach for improving data quality in a clinical registry. Comput Methods Programs Biomed 181:104840. https://doi.org/10.1016/j.cmpb.2019.01.012\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003e\u003cstrong\u003eTable 1. Patient characteristics of the study population compared to those of other hospitals from 2017 to 2022. Data are presented as means and standard deviation\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003e[\u003c/strong\u003e\u003cstrong\u003eSD\u003c/strong\u003e\u003cstrong\u003e]\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;or numbers (n) and per cent (%).\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"642\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eStudy cohort CLSS\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n=398)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSwespine CLSS\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n=25,683)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eStudy cohort LDH\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n=398)\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSwespine LDH\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n=11,752)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAge\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eMissing data\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e68.2\u0026nbsp;[9.8]\u003c/p\u003e\n \u003cp\u003e0 (0.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e68.3\u0026nbsp;[10.3]\u003c/p\u003e\n \u003cp\u003e0 (0.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e43.2\u0026nbsp;[12.5]\u003c/p\u003e\n \u003cp\u003e0 (0.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e44.7\u0026nbsp;[13.7]\u003c/p\u003e\n \u003cp\u003e0 (0)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eFemale\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eMissing data\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e195 (49.1)\u003c/p\u003e\n \u003cp\u003e1 (0.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e13,464 (52.4)\u003c/p\u003e\n \u003cp\u003e5 (0.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e176 (44.3)\u003c/p\u003e\n \u003cp\u003e1 (0.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e5,169 (44.0)\u003c/p\u003e\n \u003cp\u003e7 (0.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eBMI*\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eMissing data\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e28.1\u0026nbsp;[4.2]\u003c/p\u003e\n \u003cp\u003e127 (31.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e28.0\u0026nbsp;[22.4]\u003c/p\u003e\n \u003cp\u003e5,308 (20.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e26.8\u0026nbsp;[4.4]\u003c/p\u003e\n \u003cp\u003e167 (42.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e26.9\u0026nbsp;[20.4]\u003c/p\u003e\n \u003cp\u003e3,209 (27.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSmoking\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eMissing data\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e13 (4.5)\u003c/p\u003e\n \u003cp\u003e106 (26.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e1,068 (4.9)\u003c/p\u003e\n \u003cp\u003e4,096 (15.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e19 (8.0)\u003c/p\u003e\n \u003cp\u003e161 (40.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e785 (8.8)\u003c/p\u003e\n \u003cp\u003e2,875 (24.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eASA** 1 and 2\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eMissing data\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e202 (74.0)\u003c/p\u003e\n \u003cp\u003e125 (31.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e18,315 (76.5)\u003c/p\u003e\n \u003cp\u003e1,742 (6.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e274 (96.5)\u003c/p\u003e\n \u003cp\u003e114 (28.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e10,184 (94.6)\u003c/p\u003e\n \u003cp\u003e993 (8.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eElective surgery\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eMissing data\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e374 (95.2)\u003c/p\u003e\n \u003cp\u003e5 (1.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e24,925 (98.1)\u003c/p\u003e\n \u003cp\u003e288 (1.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e317 (81.9)\u003c/p\u003e\n \u003cp\u003e11 (2.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e10,635 (92.0)\u003c/p\u003e\n \u003cp\u003e194 (1.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePrevious surgeries\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eMissing data\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e40 (13.8)\u003c/p\u003e\n \u003cp\u003e109 (27.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e3,838 (17.8)\u003c/p\u003e\n \u003cp\u003e4,118 (16.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e29 (12.1)\u003c/p\u003e\n \u003cp\u003e158 (40.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e1,003 (11.3)\u003c/p\u003e\n \u003cp\u003e2,842 (24.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePreoperative ODI***\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eMissing data\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e43.9\u0026nbsp;[15.8]\u003c/p\u003e\n \u003cp\u003e113 (28.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e43.1\u0026nbsp;[16.05]\u003c/p\u003e\n \u003cp\u003e5,249 (20.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e50.3\u0026nbsp;[19.0]\u003c/p\u003e\n \u003cp\u003e160 (40.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e48.3\u0026nbsp;[18.1]\u003c/p\u003e\n \u003cp\u003e3,360 (27.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePreoperative EQ-5D****\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eMissing data\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e0.32\u0026nbsp;[0.32]\u003c/p\u003e\n \u003cp\u003e115 (28.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e0.36\u0026nbsp;[0.32]\u003c/p\u003e\n \u003cp\u003e5,425 (20.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e0.21\u0026nbsp;[0.32]\u003c/p\u003e\n \u003cp\u003e160 (40.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e0.25\u0026nbsp;[0.34]\u003c/p\u003e\n \u003cp\u003e3,360 (27.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSurgery with implant\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eMissing data\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e21 (7.3)\u003c/p\u003e\n \u003cp\u003e112 (28.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e2,098 (12.8)\u003c/p\u003e\n \u003cp\u003e9,332 (36.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e4 (1.4)\u003c/p\u003e\n \u003cp\u003e103 (25.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e208 (2.9)\u003c/p\u003e\n \u003cp\u003e4,617 (39.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePerioperative complications\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eMissing data\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e41 (10.3)\u003c/p\u003e\n \u003cp\u003e0 (0.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e1,874 (7.5)\u003c/p\u003e\n \u003cp\u003e846 (3.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e12 (3.0)\u003c/p\u003e\n \u003cp\u003e1 (0.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e351 (3.1)\u003c/p\u003e\n \u003cp\u003e311 (2.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e*BMI: Body mass index\u003c/p\u003e\n\u003cp\u003e**ASA \u0026ndash; American Society of Anaesthesiologists \u0026ndash; classification of physical status\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e***ODI: Oswestry Disability Index\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e****EQ-5D: EuroQol 5 Dimensions (EQ-5D)\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2. Accuracy and concordance of 398 patients registered in Swespine for surgery for lumbar spinal stenosis (CLSS) using electronic patient records (EPRs) as a reference.\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"751\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 212px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eFrequency*,\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003en (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMissing data Swespine, n (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMissing data EPRs**, n (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eProportion correctly classified, PCC*** (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 212px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDiagnosis\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e398 (100)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e98.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 212px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eType of surgery\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e391 (98.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e7 (1.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e99.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 212px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDate of surgery\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e398 (100)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e98.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 212px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDate of discharge\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e367 (92.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e31 (7.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e94.6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 212px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSide of surgery\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e360 (90.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e38 (9.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e99.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 212px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eLevel of surgery\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e396 (99.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e2 (0.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e96.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 212px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSurgery with implant\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e286 (71.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e112 (28.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 212px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eBone grafting\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e341 (85.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e57 (14.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e99.4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 212px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAntibiotic prophylaxis\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e345 (86.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e19 (4.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e34\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 212px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eThromboprophylaxis\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e328 (89.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e56 (14.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e98.2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 212px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAcute/elective operation\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e393 (98.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e5 (1.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e99.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 212px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePerioperative complications\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e398 (100)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u0026nbsp;-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e97.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 212px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eIndication for reoperation\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e388 (97.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e99.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 212px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eType of reoperation\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e390 (98.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e99.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 212px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDate of reoperation\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e390 (98.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e98.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 212px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSex\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e397 (99.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e1 (0.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 212px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eHeight\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e279 (70.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e110 (27.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e93.9\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 212px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eWeight\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e269 (67.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e120 (30.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e83.6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 212px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSmoking\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e285 (71.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e106 (26.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e99.3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 212px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eASA\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e265 (66.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e125 (31.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e78.1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e*Frequency in Swespine minus the number of patients with missing data in the EPRs for a specific variable \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e**Not verifiable information due to missing data in the EPRs\u003c/p\u003e\n\u003cp\u003e***Correctly registered data divided by verifiable cases\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 3. Accuracy and concordance of data for 398 patients with lumbar disc herniation (LDH) registered in the Swespine surgical database, using electronic patient records (EPRs) as a reference.\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" align=\"\" width=\"746\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eFrequency*,\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003en (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMissing data Swespine, n (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMissing data EPRs**, n (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eProportion correctly classified***, PCC (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDiagnosis\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e398 (100)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e99.2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eType of surgery\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e393 (98.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e5 (1.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e98.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDate of surgery\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e398 (100)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e97.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDate of discharge\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e334 (83.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e64 (16.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e96.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSide of surgery\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e380 (95.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e18 (4.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e97.1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eLevel of surgery\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e397 (99.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e1 (0.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e97.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSurgery with implant\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e295 (74.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e103 (25.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e99.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eBone grafting\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e329 (82.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e69 (17.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAntibiotic prophylaxis\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e321 (80.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e23 (5.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e54\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e99.1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eThromboprophylaxis\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e332 (83.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e55 (13.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e89.8\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAcute/elective operation\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e387 (97.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e11 (2.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e97.9\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePerioperative complications\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e397 (99.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e1 (0.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e98.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eIndication for reoperation\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e384 (96.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e7 (1.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e94.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eType of reoperation\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e385 (96.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e7 (1.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e97.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDate of reoperation\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e384 (96.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e7 (1.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e97.4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSex\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e397 (99.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e1 (0.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eHeight\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e211 (53.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e160 (40.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e95.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eWeight\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e204 (51.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e167 (42.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e87.3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSmoking\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e232 (58.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e161 (40.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e98.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eASA\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e253 (70.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 132px;\"\u003e\n \u003cp\u003e114 (28.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 180px;\"\u003e\n \u003cp\u003e74.3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e*Frequency in Swespine minus the number of patients with missing data in the EPRs for a specific variable\u003c/p\u003e\n\u003cp\u003e**Not verifiable information due to missing data in the EPRs\u003c/p\u003e\n\u003cp\u003e***Correctly registered data divided by verifiable cases\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 4. Characterization of\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003emagnetic resonance (\u003c/strong\u003e\u003cstrong\u003eMR) images of 344 patients registered in Swespine for lumbar spinal stenosis (CLSS) surgery.\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 169px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 149px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eLevel 1\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 149px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eLevel 2\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 136px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eLevel 3\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 169px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSchizas, n (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 149px;\"\u003e\n \u003cp\u003e\u003cstrong\u003en=344\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 149px;\"\u003e\n \u003cp\u003e\u003cstrong\u003en=142\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 136px;\"\u003e\n \u003cp\u003e\u003cstrong\u003en=38\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 169px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eA\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 149px;\"\u003e\n \u003cp\u003e2 (0.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 149px;\"\u003e\n \u003cp\u003e1 (0.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 136px;\"\u003e\n \u003cp\u003e2 (5.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 169px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eB\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 149px;\"\u003e\n \u003cp\u003e18 (5.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 149px;\"\u003e\n \u003cp\u003e34 (23.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 136px;\"\u003e\n \u003cp\u003e12 (31.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 169px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eC\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 149px;\"\u003e\n \u003cp\u003e169 (49.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 149px;\"\u003e\n \u003cp\u003e71 (50.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 136px;\"\u003e\n \u003cp\u003e15 (39.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 169px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eD\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 149px;\"\u003e\n \u003cp\u003e155 (45.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 149px;\"\u003e\n \u003cp\u003e36 (25.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 136px;\"\u003e\n \u003cp\u003e9 (23.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 169px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eArea* (mm\u003csup\u003e2\u003c/sup\u003e),\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003emean (95% CI)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 149px;\"\u003e\n \u003cp\u003e44.2 (42.2-46.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 149px;\"\u003e\n \u003cp\u003e62.5 (56.7-68.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 136px;\"\u003e\n \u003cp\u003e72.2 (58.9-85.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eCI: Confidence interval\u003c/p\u003e\n\u003cp\u003e* A radiologist measured the area in 52% of patients; the first author (GW) measured the area in the remaining 48%.\u003c/p\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":"european-spine-journal","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"esjo","sideBox":"Learn more about [European Spine Journal](http://link.springer.com/journal/586)","snPcode":"586","submissionUrl":"https://submission.springernature.com/new-submission/586/3","title":"European Spine Journal","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Swespine, Lumbar spinal stenosis, Lumbar disc herniation, Validity, Accuracy","lastPublishedDoi":"10.21203/rs.3.rs-6597094/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6597094/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003ePurpose: \u003c/strong\u003eTo validate the Swedish National Spine Registry (Swespine) for diagnostic accuracy and documentation of surgical procedures for central lumbar spinal stenosis (CLSS) and lumbar disc herniation (LDH), including an analysis of preoperative magnetic resonance imaging (MRI). Additionally, this study evaluates the accuracy and completeness of perioperative data and documented complications.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods: \u003c/strong\u003eOf 41,312 patients registered in Swespine for CLSS or LDH between January 2017 and December 2022, 800 were randomly selected from four hospitals. The electronic patient records were used as the gold standard. Radiological criteria for CLSS and LDH were established through a review of MRI scans.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults: \u003c/strong\u003eThe proportion of correctly classified diagnoses (PCC) was 98.5% for CLSS and 99.2% for LDH, while the PCC of the type of surgery was 99.7% and 98.5% in the CLSS and LDH cohorts, respectively. Preoperative MRI analysis showed that 94.2% of patients undergoing CLSS surgery at the narrowest spinal level were classified as Schizas C or D, with a mean cross-sectional area of 44.2 mm². In comparison, 85.0% of patients who underwent LDH surgery were classified with Pfirrman grade 3.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion: \u003c/strong\u003eSwespine demonstrated high accuracy and completeness in diagnosing and surgically treating CLSS and LDH patients, as corroborated by preoperative MRI assessments. Most perioperative data, including complications, demonstrated acceptable to excellent registration. Improvements are recommended in the documentation of the American Society of Anaesthesiologistsclassification, patient weight and height, smoking status, use of implants and bone grafts, date of discharge, use of thromboprophylaxis, and previous surgeries.\u003c/p\u003e","manuscriptTitle":"Validity and accuracy of Swespine data on surgery for central lumbar spinal stenosis and lumbar disc herniation: A Cohort Study of 796 Patients","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-05-20 09:36:45","doi":"10.21203/rs.3.rs-6597094/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-05-24T18:03:34+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-05-21T11:01:28+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-05-16T08:18:37+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"45740184355049108454706529690133488338","date":"2025-05-15T07:39:00+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"83480402039246125398425835365076232036","date":"2025-05-14T19:59:39+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-05-14T19:22:51+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-05-12T05:58:11+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-05-12T05:54:06+00:00","index":"","fulltext":""},{"type":"submitted","content":"European Spine Journal","date":"2025-05-05T19:41:29+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"european-spine-journal","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"esjo","sideBox":"Learn more about [European Spine Journal](http://link.springer.com/journal/586)","snPcode":"586","submissionUrl":"https://submission.springernature.com/new-submission/586/3","title":"European Spine Journal","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"353cf733-6a36-438e-8ee7-d49bc033600f","owner":[],"postedDate":"May 20th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-06-16T15:59:39+00:00","versionOfRecord":{"articleIdentity":"rs-6597094","link":"https://doi.org/10.1007/s00586-025-09049-8","journal":{"identity":"european-spine-journal","isVorOnly":false,"title":"European Spine Journal"},"publishedOn":"2025-06-12 15:57:13","publishedOnDateReadable":"June 12th, 2025"},"versionCreatedAt":"2025-05-20 09:36:45","video":"","vorDoi":"10.1007/s00586-025-09049-8","vorDoiUrl":"https://doi.org/10.1007/s00586-025-09049-8","workflowStages":[]},"version":"v1","identity":"rs-6597094","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6597094","identity":"rs-6597094","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}