In 1998, an international and multidisciplinary group of experts (from the fields of spine surgery, physiotherapy, occupational therapy, rheumatology, primary care medicine, internal medicine, health economics and epidemiology) proposed a short multidimensional series of core outcome items for use in patients with low back disorders. In 2005 and 2006, two independent research groups published studies validating these items when combined to form an outcome instrument that was subsequently coined the Core Outcome Measures Index for the back (COMI-back). It now exists in at least 22 languages, is used as the primary outcome measure in numerous research studies, and has been adopted by International and National Surgical and Non-Surgical Spine Registries. Its Minimal Clinically Important Change score (MCIC) for both improvement and worsening have been calculated. It has been shown to be as responsive an outcome measure as many other, long-standing legacy outcome measures (e.g. Oswestry Disability Index, ODI) and various condition-specific instruments used in assessing patients with specific pathologies such as spinal stenosis, spinal deformity, or spinal tumour. A cross-walk to convert COMI scores to ODI scores has been developed. Other musculoskeletal specialties have taken the COMI-back and modified the wording to reflect the joint being enquired about to produce COMI-neck, COMI-knee and COMI-hip versions; these have been subsequently validated for use in patients with the corresponding musculoskeletal disorders. Predictor studies using machine-learning methods and sophisticated statistical analyses have been carried out to predict post-surgical COMI scores, based on a minimal set of baseline characteristics. Part 1 of this review gives an overview of the development of the COMI and its success as a brief but responsive multidimensional outcome instrument over the last 18 years, whilst Part 2 serves to describe its content, scoring, language versions and applications.

Degenerative spondylolisthesis (DS) is addressed with a wide range of surgical techniques, though controversy exists regarding surgical technique selection. Given the lack of high-quality evidence to guide surgical technique selection in DS, appropriateness criteria and classification systems have been developed based on expert opinion. The DSIC System uses imaging and patient characteristics to predict stability. The purpose of this study was to evaluate the DSIC system as a guide for technique selection by determining if patients within each DSIC Type have different outcomes when treated with various surgical techniques. Patients undergoing surgery for symptomatic DS were prospectively enrolled at two centers. All patients were classified by DSIC Type and surgical technique. Due to small numbers in some subgroups, decompression alone and decompression with uninstrumented fusion were combined as uninstrumented group and decompression with instrumented and circumferential fusion were combined as instrumented group. The primary outcome was the 12-month change on the Core Outcome Measures Index (COMI). Of the 508 patients enrolled, 459 patients could be classified according to DSIC criteria. 10 patients were classified as DSIC Type I (stable), 366 as DSIC Type II (potentially unstable), and 83 as DSIC Type III (unstable). Surgical technique varied significantly across DSIC Type, with decompression alone performed most commonly in DSIC I and decompression and fusion performed more commonly in DSIC II and III. There were no significant differences in COMI scores between the DSIC groups at baseline, 3 or 12 months post-operatively. At 12 months, the DSIC I uninstrumented group improved by 3.48 points on the COMI compared to 1.75 points in the DSIC I instrumented group (p > 0.05). The DSIC III uninstrumented group improved by 2.94 points at 12 months compared to the DSIC III instrumented group that improved by 4.06 points (p > 0.05). DSIC II patients showed similar COMI score improvement between the surgical technique groups. All DSIC groups improved significantly from baseline with greater than 75

In 1998, an international and multidisciplinary group of experts (from the fields of spine surgery, physiotherapy, occupational therapy, rheumatology, primary care medicine, internal medicine, health economics and epidemiology) proposed a short multidimensional series of core outcome items for use in patients with low back disorders. In 2005 and 2006, two independent research groups published studies validating these items when combined to form an outcome instrument that was subsequently coined the Core Outcome Measures Index for the back (COMI-back). It now exists in at least 22 languages, is used as the primary outcome measure in numerous research studies, and has been adopted by International and National Surgical and Non-Surgical Spine Registries. Its Minimal Clinically Important Change score for both improvement and worsening have been calculated. It has been shown to be as responsive an outcome measure as many other, long-standing legacy outcome measures (e.g. Oswestry Disability Index-ODI) and various condition-specific instruments used in assessing patients with specific pathologies such as spinal stenosis, spinal deformity, or spinal tumour. A cross-walk to convert COMI scores to ODI scores has been developed. Other musculoskeletal specialties have taken the COMI-back and modified the wording to reflect the joint being enquired about to produce COMI-neck, COMI-knee and COMI-hip versions; these have been subsequently validated for use in patients with the corresponding musculoskeletal disorders. Predictor studies using machine-learning methods and sophisticated statistical analyses have been carried out to predict post-surgical COMI scores, based on a minimal set of baseline characteristics. Part 1 of this review gives an overview of the development of the COMI and its success as a brief but responsive multidimensional outcome instrument over the last 18 years, whilst Part 2 serves to describe its content, scoring, language versions and applications.

The reliability of patient-reported outcome measures is typically evaluated in patients with chronic or stable symptoms, pre-treatment. After treatment, symptoms may be less extreme and less variable within a group, which may influence indices of reliability. Further, few studies have examined the reliability of retrospective, single item global assessment scores after treatment, despite the latter often being used as the external criterion when determining an instrument’s minimal clinically important change (MCIC) score. This study examined the stability of Core Outcome Measures Index (COMI) and Global Treatment Outcome (GTO) scores after spine surgery. Data were extracted for patients with lumbar spinal stenosis who had completed the COMI and GTO twice at follow-up, for both an in-house outcomes database (ROUTINE) and as part of a separate prospective study (LSOS). To be included, the questionnaires had to have been completed within 3 months of each other for 1-year follow-up (FU), within 4 months for 2-year FU and within 5 months for 5-year FU. Repeated measures ANOVA, intraclass correlation coefficients (ICC; 2-way mixed, absolute agreement), and weighted Kappa values were calculated. 64 patients (72.9 ± 6.9 y; 48

Study Design.Heterogeneous data collection through a mix of prospective, retrospective, and ambispective methods. Objective.To evaluate the effect of biological sex on patient-reported outcomes after spinal fusion surgery for lumbar degenerative disease. Summary of Background Data.Current literature suggests sex differences regarding clinical outcome after spine surgery may exist. Substantial methodological heterogeneity and limited comparability of studies warrants further investigation of sex-related differences in treatment outcomes. Materials and Methods.We analyzed patients who underwent spinal fusion with or without pedicle screw insertion for lumbar degenerative disease included within a multinational study, comprising patients from 11 centers in seven countries. Absolute values and change scores (change from preoperative baseline to postoperative follow-up) for 12-month functional impairment [Oswestry disability index (ODI)] and back and leg pain severity [numeric rating scale (NRS)] were compared between male and female patients. Minimum clinically important difference (MCID) was defined as >30% improvement. Results.Six-hundred sixty (59%) of 1115 included patients were female. Female patients presented with significantly baseline ODI (51.5 +/- 17.2 vs. 47.8 +/- 17.9, P<0.001), back pain (6.96 +/- 2.32 vs. 6.60 +/- 2.30, P=0.010) and leg pain (6.49 +/- 2.76 vs. 6.01 +/- 2.76, P=0.005). At 12 months, female patients still reported significantly higher ODI (22.76 +/- 16.97 vs. 20.50 +/- 16.10, P=0.025), but not higher back (3.13 +/- 2.38 vs. 3.00 +/- 2.40, P=0.355) or leg pain (2.62 +/- 2.55 vs. 2.34 +/- 2.43, P=0.060). Change scores at 12 months did not differ significantly among male and female patients in ODI (triangle 1.31, 95% CI: -3.88 to 1.25, P=0.315), back (triangle 0.22, 95% CI: -0.57 to 0.12, P=0.197), and leg pain (triangle 0.16, 95% CI: -0.56 to 0.24, P=0.439). MCID at 12 months was achieved in 330 (77.5%) male patients and 481 (76.3%) female patients (P=0.729) for ODI. Conclusion.Both sexes experienced a similar benefit from surgery in terms of relative improvement in scores for functional impairment and pain. Although female patients reported a higher degree of functional impairment and pain preoperatively, at 12 months only their average scores for functional impairment remained higher than those for their male counterparts, while absolute pain scores were similar for female and male patients.

The aim of this study was to investigate the risks and outcomes of patients with long-term oral anticoagulation (OAC) undergoing spine surgery. All patients on long-term OAC who underwent spine surgery between 01/2005 and 06/2015 were included. Data were prospectively collected within our in-house Spine Surgery registry and retrospectively supplemented with patient chart and administrative database information. A 1:1 propensity score-matched group of patients without OAC from the same time interval served as control. Primary outcomes were post-operative bleeding, wound complications and thromboembolic events up to 90 days post-surgery. Secondary outcomes included intraoperative blood loss, length of hospital stay, death and 3-month post-operative patient-rated outcomes. In comparison with the control group, patients with OAC (n = 332) had a 3.4-fold (95

This study aimed to develop machine learning methods to estimate bone mineral density and detect osteopenia/osteoporosis from conventional lumbar MRI (T1-weighted and T2-weighted images) and planar radiography in combination with clinical data and imaging parameters of the acquisition protocol. A database of 429 patients subjected to lumbar MRI, radiographs and dual-energy x-ray absorptiometry within 6 months was created from an institutional database. Several machine learning models were trained and tested (373 patients for training, 86 for testing) with the following objectives: (1) direct estimation of the vertebral bone mineral density; (2) classification of T-score lower than − 1 or (3) lower than − 2.5. The models took as inputs either the images or radiomics features derived from them, alone or in combination with metadata (age, sex, body size, vertebral level, parameters of the imaging protocol). The best-performing models achieved mean absolute errors of 0.15–0.16 g/cm2 for the direct estimation of bone mineral density, and areas under the receiver operating characteristic curve of 0.82 (MRIs) − 0.80 (radiographs) for the classification of T-scores lower than − 1, and 0.80 (MRIs) − 0.65 (radiographs) for T-scores lower than − 2.5. The models showed good discriminative performances in detecting cases of low bone mineral density, and more limited capabilities for the direct estimation of its value. Being based on routine imaging and readily available data, such models are promising tools to retrospectively analyse existing datasets as well as for the opportunistic investigation of bone disorders.

BACKGROUND:Substantial variation exists in surgeon decision making. In response, multiple specialty societies have established criteria for the appropriate use of spine surgery. Yet few strategies exist to facilitate routine use of appropriateness criteria by surgeons. Behavioral science nudges are increasingly used to enhance decision making by clinicians. We sought to design "surgical appropriateness nudges" to support routine use of appropriateness criteria for degenerative lumbar scoliosis and spondylolisthesis.METHODS:The work reflected Stage I of the NIH Stage Model for Behavioral Intervention Development and involved an iterative, multi-method approach, emphasizing qualitative methods. Study sites included two large referral centers for spine surgery. We recruited spine surgeons from both sites for two rounds of focus groups. To produce preliminary nudge prototypes, we examined sources of variation in surgeon decision making (Focus Group 1) and synthesized existing knowledge of appropriateness criteria, behavioral science nudge frameworks, electronic tools, and the surgical workflow. We refined nudge prototypes via feedback from content experts, site leaders, and spine surgeons (Focus Group 2). Concurrently, we collected data on surgical practices and outcomes at study sites. We pilot tested the refined nudge prototypes among spine surgeons, and surveyed them about nudge applicability, acceptability, and feasibility (scale 1-5, 5 = strongly agree).RESULTS:Fifteen surgeons participated in focus groups, giving substantive input and feedback on nudge design. Refined nudge prototypes included: individualized surgeon score cards (frameworks: descriptive social norms/peer comparison/feedback), online calculators embedded in the EHR (decision aid/mapping), a multispecialty case conference (injunctive norms/social influence), and a preoperative check (reminders/ salience of information/ accountable justification). Two nudges (score cards, preop checks) incorporated data on surgeon practices and outcomes. Six surgeons pilot tested the refined nudges, and five completed the survey (83%). The overall mean score was 4.0 (standard deviation [SD] 0.5), with scores of 3.9 (SD 0.5) for applicability, 4.1 (SD 0.5) for acceptability, and 4.0 (SD 0.5), for feasibility. Conferences had the highest scores 4.3 (SD 0.6) and calculators the lowest 3.9 (SD 0.4).CONCLUSIONS:Behavioral science nudges might be a promising strategy for facilitating incorporation of appropriateness criteria into the surgical workflow of spine surgeons. Future stages in intervention development will test whether these surgical appropriateness nudges can be implemented in practice and influence surgical decision making.

BACKGROUND:The long-term impact of reoperations following adult spinal deformity (ASD) surgery is still poorly understood. Our aim was to identify the relationship between unplanned reoperation and health-related quality of life (HRQoL) gain at 2 and 5 years of follow-up. METHODS:We included patients enrolled in a prospective ASD database who underwent surgery ≥5 years prior to the start of the study and who had 2 years of follow-up data. Adverse events (AEs) leading to an unplanned reoperation, the time of reoperation occurrence, invasiveness (blood loss, surgical time, hospital stay), and AE resolution were assessed. HRQoL was measured with use of the Oswestry Disability Index, Scoliosis Research Society-22, and Short Form-36. Linear models controlling for baseline data and index surgery characteristics were utilized to assess the relationships between HRQoL gain at 2 and 5-year follow-up and the number and invasiveness of reoperations. The association between 5-year HRQoL gain and the time of occurrence of the unplanned reoperation and that between 5-year HRQoL gain and AE resolution were also investigated. RESULTS:Of 361 eligible patients, 316 (87.5%) with 2-year follow-up data met the inclusion criteria and 258 (71.5%) had 5-year follow-up data. At the 2-year follow-up, 96 patients (30.4%) had a total of 165 unplanned reoperations (1.72 per patient). At the 5-year follow-up, 73 patients (28.3%) had a total of 117 unplanned reoperations (1.60 per patient). The most common cause of reoperations was mechanical complications (64.9%), followed by surgical site infections (15.7%). At the 5-year follow-up, the AE that led to reoperation was resolved in 67 patients (91.8%). Reoperation invasiveness was not associated with 5-year HRQoL scores. The number of reoperations was associated with lesser HRQoL gain at 5 years for all HRQoL measures. The mean associated reduction in HRQoL gain per unplanned reoperation was 41% (range, 19% to 66%). Reoperations resulting in no resolution of the AE or resolution with sequelae had a greater impact on 5-year follow-up HRQoL scores than reoperations resulting in resolution of the AE. CONCLUSIONS:A postoperative, unplanned reoperation following ASD surgery was associated with lesser gain in HRQoL at 5 years of follow-up. The association did not diminish over time and was affected by the number, but not the magnitude, of reoperations. Resolution of the associated AE reduced the impact of the unplanned reoperation. LEVEL OF EVIDENCE:Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Study Design. A single-centre retrospective study of prospectively collected data. Objective. Analyse factors associated with the patient-reported outcome after far lateral decompression surgery (FLDS) for lumbar nerve root compression using the far-lateral approach. Summary of Background Data. To date, no studies have investigated the influence of vertebral level, coronal segmental Cobb angle, and the nature of the compressive tissue (hard or soft) on the patient-reported outcome following FLDS. Patients and Methods. Patients who had undergone FLDS between 2005 and 2020 were included. Coronal segmental angle (CSCA) was measured on preoperative, posteroanterior radiographs. The primary outcome measure was the core outcome measures index (COMI) score at two years' follow-up (2Y-FU). Patients who had undergone microsurgical decompression using a midline approach served as a comparator group. Results. There were 148 FLDS and 463 midline approach patients. In both groups, there was a significant improvement in the COMI score from preoperative to 2Y-FU (P<0.0001), with greater improvement in patients treated at higher vertebral levels than in those treated at L5/S1 (P=0.014). Baseline COMI, American Society of Anesthesiologists grade, body mass index, and low back pain as the "chief complaint" all had a significant association with the two-year COMI score. The nature of compressive tissue showed no association with the COMI score at 2Y-FU. In the FLDS group, there was a statistically significant correlation between the preoperative CSCA and the change in COMI score preoperatively to 2Y-FU (P<0.001). The association was retained in the multiple regression analysis, controlling for confounders. A one-degree increase in CSCA was associated with a 0.35-point worse COMI score at 2Y-FU (P=0.003). Conclusion. Treatment of far lateral nerve root compression showed an overall good patient-reported outcome, but with less improvement with advanced CSCA. Modified approaches and techniques might be preferable for levels L5/S1.

Psychosocial distress (the presence of yellow flags) has been linked to poor outcomes in spine surgery. The Core Yellow Flags Index (CYFI), a short instrument assessing the 4 main yellow flags, was developed for use in patients undergoing lumbar spine surgery. This study evaluated its ability to predict outcome in patients undergoing cervical spine surgery. Patients with degenerative spinal disorders (excluding myelopathy) operated in one centre, from 2015 to 2019, were asked to complete the CYFI at baseline and the Core Outcome Measures Index (COMI) at baseline and 3 and 12 months after surgery. The relationship between CYFI and COMI scores at baseline as well as the predictive ability of the CYFI on the COMI follow-up scores were tested using structural equation modelling. From 731 eligible patients, 547 (61.0 ± 12.5 years; 57.2

Low-grade isthmic and degenerative spondylolisthesis (DS) of the lumbar spine are distinct pathologies but both can be treated with lumbar decompression with fusion. In a very large cohort, we compared patient-reported outcome in relation to the pathology and chief complaint at baseline. This was a retrospective analysis using the EUROSPINE Spine Tango Registry. We included 582 patients (age 60 ± 15 years; 65

Purpose The core outcome measures index (COMI) for the back is a questionnaire that evaluates five domains and has been translated into several languages and validated for different populations. We aimed to translate, cross-culturally adapt and validate it in European Portuguese for use in patients with degenerative lumbar disease. Additionally, we aimed to establish the minimal clinically important change score (MCIC). Methods The translation and cultural adaptation were done according to published guidelines. Patients awaiting surgery at a neurosurgical center completed the COMI, Oswestry Disability Index (ODI), EQ-5D questionnaires and a pain visual analog scale (VAS). To evaluate COMI’s reproducibility, patients completed the questionnaire twice within two weeks, preoperatively, in addition to answering a transition question. The MCIC was determined by analysis of postoperative changes in total COMI score, using the anchor method, with a question ascertaining surgical outcome as perceived by the patient. Results The first set of questionnaires was answered by 108 patients and the second, by 98 patients. COMI's construct validity was confirmed by demonstrating the hypothesized correlation between each domain’s score (Spearman Rho > 0.4) and the corresponding questionnaire score (ODI, EQ-5D and VAS) and through adequate correlation (Spearman > 0.6) between COMI's total score and ODI and EQ-5D total scores. Intraclass correlation coefficients between each domain and COMI’s total score were > 0.8. The MCIC was calculated as 2.1. Conclusion The cross-culturally adapted COMI questionnaire is a valid clinical assessment tool for European Portuguese-speaking patients with degenerative lumbar disease, with an MCIC of 2.1 points.

Introduction:Epimuscular fat (EF) has rarely been studied in the context of low back pain (LBP). Research question:This study aims to assess the presence and extent of EF in the lumbar muscles and its association with vertebral level in patients with low back disorders and to explore correlations between EF, demographics, BMI, and LBP. Material and methods:T2 axial MRIs from L1 to L5 were manually segmented to analyze the cross-sectional area (CSA) of EF (mm2), and fat infiltration (FI,%) of 40 patients (23 females, 17 males; mean age:65.9 years) with lumbar degenerative pathologies awaiting a surgical procedure. COMI, LBP, demographic, and clinical data were extracted from the institutional registry. Statistical analyses included Wilcoxon and Mann-Whitney tests for differences in EF between sides and sexes, the Friedman test for EF size differences among lumbar levels, and Spearman's correlation for associations, adjusted for BMI, age, and sex. Results:EF was found in 77.5% of subjects at L1, 92.5% at L2, 100% at L3 and L4, and 95.0% at L5. EF was significantly larger at L4 (253.1 ± 183.6 mm2) and L5 (220.2 ± 194.9 mm2) than at L1 (36.1 ± 37.8 mm2) and L2 (72.2 ± 84.4 mm2). No significant EF differences were found between sides and sexes. EF correlated strongly with BMI (rs = 0.65,p < 0.001) and moderately with FI (rs = 0.31,p = 0.04), though its correlation with FI was not significant after adjustment. EF did not correlate with COMI scores but correlated with LBP in the adjusted analysis (rs:0.31,p = 0.04). Discussion and conclusion:EF is present across all lumbar levels, with higher concentrations at L4 and L5, and a significant correlation between EF and LBP intensity was observed. The present findings are limited to a specific subset of patients with lumbar degenerative disorders who are awaiting surgical procedures.

IntroductionThe Minimal Clinically Important Change (MCIC) is used in conjunction with Patient-Reported Outcome Measures (PROMs) to determine the clinical relevance of changes in health status. MCIC measures a change within the same person or group over time. This study aims to evaluate the variability in computing MCIC for the Core Outcome Measure Index (COMI) using different methods.MethodsData from a spine centre in Switzerland were used to evaluate variations in MCIC for the COMI score. Distribution-based and anchor-based methods (predictive and nonpredictive) were applied. Bayesian bootstrap estimated confidence intervals.ResultsFrom 27,003 cases, 9821 met the inclusion criteria. Distribution-based methods yielded MCIC values from 0.4 to 1.4. Anchor-based methods showed more variability, with MCIC values from 1.5 to 4.9. Predictive anchor-based methods also provided variable MCIC values for improvement (0.3-2.4), with high sensitivity and specificity.DiscussionMCIC calculation methods produce varying values, emphasizing careful method selection. Distribution-based methods likely measure minimal detectable change, while non-predictive anchor-based methods can yield high MCIC values due to group averaging. Predictive anchor-based methods offer more stable and clinically relevant MCIC values for improvement but are affected by prevalence and reliability corrections.

Study design: Heterogeneous data collection via a mix of prospective, retrospective, and ambispective methods. Objective: To evaluate the effect of biological sex on patient-reported outcomes after spinal fusion surgery for lumbar degenerative disease. Summary of Background Data: Current literature suggests sex differences regarding clinical outcome after spine surgery may exist. Substantial methodological heterogeneity and limited comparability of studies warrants further investigation of sex-related differences in treatment outcomes. Methods: We analyzed patients who underwent spinal fusion with or without pedicle screw insertion for lumbar degenerative disease included within a multinational study, comprising patients from 11 centers in 7 countries. Absolute values and change scores (change from pe-operative baseline to post-operative follow-up) for 12-month functional impairment (Oswestry disability index [ODI]) and back and leg pain severity (numeric rating scale [NRS]) were compared between male and female patients. Minimum clinically important difference (MCID) was defined as > 30% improvement. Results: Six-hundred-sixty (59%) of 1115 included patients were female. Female patients presented with significantly baseline ODI (51.5 ± 17.2 vs. 47.8 ± 17.9, P<0.001) and back pain (6.96 ± 2.32 vs. 6.60 ± 2.30, P=0.010) and leg pain (6.49 ± 2.76 vs. 6.01 ± 2.76, P=0.005). At 12-months, female patients still reported significantly higher ODI (22.76 ± 16.97 vs. 20.50 ± 16.10, P=0.025), but not higher back (3.13 ± 2.38 vs. 3.00 ± 2.40, P=0.355) or leg pain (2.62 ± 2.55 vs. .34 ± 2.43, P=0.060). Change scores at 12 months did not differ significantly among male and female patients in ODI (∆ 1.31, 95% CI -3.88-1.25, P=0.315), back (∆ 0.22, 95% CI -0.57-0.12, P=0.197) and leg pain (∆ 0.16, 95% CI -0.56-0.24, P=0.439). MCID at 12-months was achieved in 330 (77.5%) male patients and 481 (76.3%) female patients (P=0.729) for ODI. Conclusion: Both sexes experienced a similar benefit from surgery in terms of relative improvement in scores for functional impairment and pain. Although female patients reported a higher degree of functional impairment and pain preoperatively, at 12 months only their average scores for functional impairment remained higher than those for their male counterparts, while absolute pain scores were similar for female and male patients.

Selecting patients with lumbar degenerative spondylolisthesis (LDS) for surgery is difficult. Appropriate use criteria (AUC) have been developed to clarify the indications for LDS surgery but have not been evaluated in controlled studies. This prospective, controlled, multicentre study involved 908 patients (561 surgical and 347 non-surgical controls; 69.5 ± 9.7y; 69