The use of the Core Yellow Flags Index for the assessment of psychosocial distress in patients undergoing surgery of the cervical spine.

BACKGROUND: 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. METHODS: 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. RESULTS: From 731 eligible patients, 547 (61.0 ± 12.5 years; 57.2% female) completed forms at all three timepoints. On a cross-sectional basis, preoperative CYFI and COMI scores were highly correlated (ß = 0.54, in men and 0.51 in women; each p < 0.001). CYFI added significantly and independently to the prediction of COMI at 3 months' FU in men (ß = 0.36) and 12 months' FU in men and women (both ß = 0.20) (all p < 0.001). CONCLUSION: The CYFI had a low to moderate but significant and independent association with cervical spine surgery outcomes. Implementing the CYFI in the preoperative workup of these patients could help refine outcome predictions and better manage patient expectations.

Evaluation of "appropriate use criteria" for surgical decision-making in lumbar degenerative spondylolisthesis. A controlled, multicentre, prospective observational study.

INTRODUCTION: 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. METHODS: This prospective, controlled, multicentre study involved 908 patients (561 surgical and 347 non-surgical controls; 69.5 ± 9.7y; 69% female), treated as per normal clinical practice. Their appropriateness for surgery was afterwards determined using the AUC. They completed the Core Outcome Measures Index (COMI) at baseline and 12 months' follow-up. Multiple regression adjusting for confounders evaluated the influence of appropriateness designation and treatment received on the 12-month COMI and achievement of MCIC (≥ 2.2-point-reduction). RESULTS: As per convention, appropriate (A) and uncertain (U) groups were combined for comparison with the inappropriate (I) group. For the adjusted 12-month COMI, the benefit of surgery relative to non-surgical care was not significantly greater for the A/U than the I group (p = 0.189). There was, however, a greater treatment effect of surgery for those with higher baseline COMI (p = 0.035). The groups' adjusted probabilities of achieving MCIC were: 83% (A/U, receiving surgery), 71% (I, receiving surgery), 50% (A/U, receiving non-surgical care), and 32% (I, receiving non-surgical care). CONCLUSIONS: A/U patients receiving surgery had the highest chances of achieving MCIC, but the AUC were not able to identify which patients had a greater treatment effect of surgery relative to non-surgical care. The identification of other characteristics that predict a greater treatment effect of surgery, in addition to baseline COMI, is required to improve decision-making.

Far Lateral Lumbar Decompression Using the Far-Lateral Approach: Patient Reported Outcome is Associated with the Involved Vertebral Level and Coronal Segmental Angle.

STUDY DESIGN: Single centre retrospective study of prospectively collected data. OBJECTIVE: Analyse factors associated with 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/soft) on patient reported outcome following FLDS. METHODS: Patients who had undergone FLDS between 2005 and 2020 were included. Coronal segmental angle (CSCA) was measured on preoperative, posteroanterior radiographs. Primary outcome measure was the Core Outcome Measures Index (COMI) score at 2 years' follow-up (2Y-FU). Patients who had undergone microsurgical decompression using a midline approach (MID) served as a comparator group. RESULTS: There were 148 FLDS and 463 MID patients. In both groups there was a significant improvement in 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, ASA grade, BMI, and low back pain as the "chief complaint" all had a significant association with the 2-year COMI score. The nature of compressive tissue showed no association with COMI score at 2Y-FU. In the FLDS group, there was a statistically significant correlation between the preoperative CSCA and change in COMI score preoperatively to 2Y-FU (P<0.001). The association was retained in 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 overall good patient reported outcome, but with less improvement with advanced coronal segmental angulation. Modified approaches and techniques might be preferable for the level L5/S1.

Evaluation of the Clinical and Radiographic Degenerative Spondylolisthesis (CARDS) classification system as a guide to surgical technique selection.

BACKGROUND CONTEXT: The role of fusion in degenerative spondylolisthesis (DS) is controversial. The Clinical and Radiographic Degenerative Spondylolisthesis (CARDS) classification system was developed to assist surgeons in surgical technique selection based on individual patient characteristics. This system has not been clinically validated as a guide to surgical technique selection. PURPOSE: The purpose of this study was to determine if outcomes vary with different surgical techniques across the CARDS categories. STUDY DESIGN/SETTING: Prospective cohort study performed at one Swiss and one American spine center. PATIENT SAMPLE: Five hundred eight patients with DS undergoing surgical treatment. OUTCOME MEASURES: Core Outcomes Measure Index (COMI) at 3 months and 12 months postoperatively. METHODS: Patients undergoing surgery for DS were enrolled at 2 institutions and classified according to the CARDS system using dynamic radiographs. The Core Outcome Measure Index (COMI) was completed preoperatively, and 3 and 12 months postoperatively. Surgical technique was classified as uninstrumented (decompression alone or decompression with uninstrumented fusion) or instrumented (decompression with pedicle screw instrumentation with or without interbody fusion). Unadjusted analyses and mixed effect models compared COMI scores between the two surgery technique groups (uninstrumented vs instrumented), stratified by CARDS category over time. Reoperation rates were also compared between the surgery technique groups stratified by CARDS category. Partial funding was given through NASS grant for clinical research. RESULTS: Five hundred five out of 508 patients enrolled in the study had sufficient data to be classified according to CARDS. Seven percent were classified as CARDS A, 28% as CARDS B, 48% as CARDS C, and 17% as CARDS D (CARDS A most "stable," CARDS D least "stable"). One hundred and thirty-three patients (26%) underwent decompression alone, 30 (6%) underwent decompression and uninstrumented fusion, 42 (8%) underwent decompression and posterolateral instrumented fusion, and 303 (60%) underwent decompression with posterolateral and interbody instrumented fusion. Patients in the least "stable" categories tended to be less likely to be treated with an uninstrumented technique (CARDS D 19% vs 32% for the other categories, p=.10). There were no significant differences in 3 or 12-month COMI scores between surgical technique groups stratified by CARDS category in the unadjusted or adjusted analyses. In the unadjusted analyses, there was a trend towards less improvement in 12-month COMI change score in the CARDS D patients in the uninstrumented group compared to the instrumented group (-2.7 vs -4.1, p=.10). Reoperation rates were not significantly different between the surgical technique groups stratified by CARDS category. CONCLUSIONS: In general, outcomes for uninstrumented and instrumented surgical techniques were similar across the CARDS categories. Surgeons likely took factors included in CARDS into account during surgical technique selection. This resulted in a low number of CARDS D (n=15) patients being treated with uninstrumented techniques, which limited the statistical power of this analysis. As such, this study does not validate CARDS as a useful classification system for surgical technique selection in DS.

Does loss to follow-up lead to an overestimation of treatment success? Findings from a spine surgery registry of over 15,000 patients.

PURPOSE: Patient-reported outcome measures (PROMs) are integral to the assessment of treatment success, but loss to follow-up (attrition) may lead to bias in the results reported. We sought to evaluate the extent, nature and implications of attrition in a long-established, single-centre spine registry. METHODS: The registry contained the data of 15,264 consecutive spine surgery patients. PROMs included the Core Outcome Measures Index (COMI) and a rating of the Global Treatment Outcome (GTO) and Satisfaction with Care. Baseline characteristics associated with returning a 12-month PROM (= "responder") were analysed (logistic regression). The 3-month outcomes of 12-month responders versus 12-month non-responders were compared (ANOVA and Chi-square). RESULTS: In total, 14,758/15,264 (97%) patients (60 ± 17y; 46% men) had consented to the use of their registry data for research. Preoperative, 3-month post-operative and 12-month post-operative PROMs were returned by 91, 90 and 86%, respectively. Factors associated with being a 12-month responder included: greater age, born in the country of the study, no private/semi-private insurance, better baseline status (lower COMI score), fewer previous surgeries, less comorbidity and no perioperative medical complications. 12-month non-responders had shown significantly worse outcomes in their 3-month PROMs than had 12-month responders (respectively, 66% vs 80% good GTO ("treatment helped/helped a lot"); 77% vs 88% satisfied/very satisfied; and 49% vs 63% achieved MCIC on COMI). CONCLUSION: Although attrition in this cohort was relatively low, 12-month non-responders displayed distinctive characteristics and their early outcomes were significantly worse than those of 12-month responders. If loss to follow-up is not addressed, treatment success will likely be overestimated, with erroneously optimistic results being reported.

Incidence of Revision Surgery After Decompression With vs Without Fusion Among Patients With Degenerative Lumbar Spinal Stenosis.

Importance: Only limited data derived from large prospective cohort studies exist on the incidence of revision surgery among patients who undergo operations for degenerative lumbar spinal stenosis (DLSS). Objective: To assess the cumulative incidence of revision surgery after 2 types of index operations-decompression alone or decompression with fusion-among patients with DLSS. Design, Setting, and Participants: This cohort study analyzed data from a multicenter, prospective cohort study, the Lumbar Stenosis Outcome Study, which included patients aged 50 years or older with DLSS at 8 spine surgery and rheumatology units in Switzerland between December 2010 and December 2015. The follow-up period was 3 years. Data for this study were analyzed between October and November 2021. Exposures: All patients underwent either decompression surgery alone or decompression with fusion surgery for DLSS. Main Outcomes and Measures: The primary outcome was the cumulative incidence of revision operations. Secondary outcomes included changes in the following patient-reported outcome measures: Spinal Stenosis Measure (SSM) symptom severity (higher scores indicate more pain) and physical function (higher scores indicate more disability) subscale scores and the EuroQol Health-Related Quality of Life 5-Dimension 3-Level questionnaire (EQ-5D-3L) summary index score (lower scores indicate worse quality of life). Results: A total of 328 patients (165 [50.3%] men; median age, 73.0 years [IQR, 66.0-78.0 years]) were included in the analysis. Of these, 256 (78.0%) underwent decompression alone and 72 (22.0%) underwent decompression with fusion. The cumulative incidence of revisions after 3 years of follow-up was 11.3% (95% CI, 7.4%-15.1%) for the decompression alone group and 13.9% (95% CI, 5.5%-21.5%) for the fusion group (log-rank P = .60). There was no significant difference in the need for revision between the 2 groups over time (unadjusted absolute risk difference, 2.6% [95% CI, -6.3% to 11.4%]; adjusted absolute risk difference, 3.9% [95% CI, -5.2% to 17.0%]; adjusted hazard ratio, 1.40 [95% CI, 0.63-3.13]). The number of revisions was significantly associated with higher SSM symptom severity scores (ß, 0.171; 95% CI, 0.047-0.295; P = .007) and lower EQ-5D-3L summary index scores (ß, -0.061; 95% CI, -0.105 to -0.017; P = .007) but not with higher SSM physical function scores (ß, 0.068; 95% CI, -0.036 to 0.172; P = .20). The type of index operation was not significantly associated with the corresponding outcomes. Conclusions and Relevance: This cohort study showed no significant association between the type of index operation for DLSS-decompression alone or fusion-and the need for revision surgery or the outcomes of pain, disability, and quality of life among patients after 3 years. Number of revision operations was associated with more pain and worse quality of life.

Association between the appropriateness of surgery, according to appropriate use criteria, and patient-rated outcomes after surgery for lumbar degenerative spondylolisthesis.

INTRODUCTION: Treatment failures in spine surgery are often attributable to poor patient selection and the application of inappropriate treatment. We used published appropriate use criteria (AUC) to evaluate the appropriateness of surgery in a large group of patients operated for lumbar degenerative spondylolisthesis (LDS) and to evaluate its association with outcome. METHODS: This was a retrospective analysis of prospectively collected outcome data from patients operated in our Spine Centre, 2005-2012. Appropriateness of surgery was judged based on the AUC. Patients had completed the multidimensional Core Outcome Measures Index (COMI) before surgery and at 3 months' and 1, 2 and 5 years' follow-up (FU). RESULTS: In total, 448 patients (69.8 ± 9.6 years; 323 (72%) women) were eligible for inclusion and the AUC could be applied in 393 (88%) of these. Surgery was considered appropriate (A) in 234 (59%) of the patients, uncertain/equivocal (U) in 90 (23%) and inappropriate (I) in 69 (18%). A/U patients had significantly (p < 0.05) greater improvements in COMI than I patients at each FU time point. The minimal clinically important change (MCIC) score for COMI was reached by 82% A, 76% U and 54% I patients at 1-year FU (p < 0.001, I vs A and U); the odds of achieving MCIC were 3-4 times greater in A/U patients than in I patients. CONCLUSIONS: The results suggest a relationship between appropriateness of surgery for LDS and the improvements in COMI score after surgery. The findings require confirmation in prospective studies that also include a control group of non-operated patients.

Validation of a surgical invasiveness index in patients with lumbar spinal disorders registered in the Spine Tango registry.

INTRODUCTION: Being able to quantify the invasiveness of a surgical procedure is important to weigh up its associated risks, since invasiveness governs the blood loss, operative time and likelihood of complications. Mirza et al. (Spine (Phila Pa 1976) 33:2651-2661, 2008) published an invasiveness index for spinal surgery. We evaluated the validity of a modified version of the Mirza invasiveness index (mMII), adapted for use with registry data. METHODS: A cross-sectional analysis was performed with data acquired from the Spine Tango registry including 21,634 patients. The mMII was calculated as the sum of six possible interventions on each vertebral level: decompression, fusion and stabilization either on anterior or posterior structures. The association between the mMII and blood loss, operative time and complications was evaluated using multiple regression, adjusting for possible confounders. RESULTS: The mean (± SD) mMII was 3.9 ± 5.0 (range 0-40). A 1-point increase in the mMII was associated with an additional blood loss of 12.8% (95% CI 12.6-13.0; p < 0.001) and an increase of operative time of 10.4 min (95% CI 10.20-10.53; p < 0.001). The R2 for the blood loss model was of 43% and for operative time, 47%. The mean mMII was significantly (p < 0.001) higher in patients with surgical complications (4.5 ± 5.6) and general medical complications (6.5 ± 7.0) compared to those without (3.8 ± 4.9). Our results were comparable to those reported in the original publication of Mirza et al. CONCLUSION: The mMII appeared to be a valid measure of surgical invasiveness in our study population. It can be used in predictor models and to adjust for surgical case-mix when comparing outcomes in different studies or different hospitals/surgeons in a registry.

Long-term Results After Surgical or Nonsurgical Treatment in Patients With Degenerative Lumbar Spinal Stenosis: A Prospective Multicenter Study.

STUDY DESIGN: Prospective, multicenter cohort study. OBJECTIVE: The aim of our study was to assess the course of patients over a period of 3 years undergoing surgical or nonsurgical treatments for degenerative lumbar spinal stenoses (DLSS) based on data from the Lumbar Stenosis Outcome Study (LSOS), prospectively performed in eight hospitals. SUMMARY OF BACKGROUND DATA: The optimal treatment strategy for patients with DLSS is still debated. METHODS: The outcomes of patients with verified DLSS were quantified by Spinal Stenosis Measure (SSM) symptoms- and SSM function-scores, and EQ-5D-3L (quality of life) summary index (SI) over time (up to 36-month follow-up), and minimal clinically important difference (MCID) in SSM symptoms, SSM function, and EQ-5D-3L SI from baseline to 36-month follow-up. RESULTS: For this study, 601 patients met the inclusion criteria; 430 underwent surgery, 18 of them only after more than a year after enrolment, 171 received nonsurgical treatment only. At baseline, patients in the surgical and nonsurgical groups had similar values for the SSM symptoms and SSM function scores, but patients in the surgical group suffered significantly more from buttocks pain and reported more worsening symptoms over the last 3 months before enrollment in the study. Surgically treated patients (except changers) performed significantly better in all clinical outcome measures (P < 0.001) with a plateau at 12-month follow-up staying constant until the follow-up ended. Further, two-thirds of patients in the surgical group had a relevant improvement in function, symptoms, and quality of life, compared with only about half of those in terms of symptoms and even less in terms of function and quality of life with nonsurgical treatment. CONCLUSIONS: Surgical treatment of DLSS results in more favorable clinical outcomes with a sustained effect over time, compared to nonsurgical treatment. LEVEL OF EVIDENCE: 3.

Development of the "Core Yellow Flags Index" (CYFI) as a brief instrument for the assessment of key psychological factors in patients undergoing spine surgery.

BACKGROUND: Depression, anxiety, catastrophising, and fear-avoidance beliefs are key "yellow flags" (YFs) that predict a poor outcome in back patients. Most surgeons acknowledge the importance of YFs but have difficulty assessing them due to the complexity of the instruments used for their measurement and time constraints during consultations. We performed a secondary analysis of existing questionnaire data to develop a brief tool to enable the systematic evaluation of YFs and then tested it in clinical practice. METHODS: The following questionnaire datasets were available from a total of 932 secondary/tertiary care patients (61 ± 16 years; 51% female): pain catastrophising (N = 347); ZUNG depression (N = 453); Hospital Anxiety and Depression Scale (anxiety subscale) (N = 308); fear-avoidance beliefs (N = 761). The single item that best represented the full-scale score was identified, to form the 4-item "Core Yellow Flags Index" (CYFI). 2422 patients (64 ± 16 years; 54% female) completed CYFI and a Core Outcome Measures Index (COMI) before lumbar spine surgery, and a COMI 3 and 12 months later (FU). RESULTS: The item-total correlation for each item with its full-length questionnaire was: 0.77 (catastrophising), 0.67 (depression), 0.69 (anxiety), 0.68 (fear-avoidance beliefs). Cronbach's α for the CYFI was 0.79. Structural equation modelling showed CYFI uniquely explained variance (p < 0.001) in COMI at both the 3- and 12-month FUs (ß = 0.11 (women), 0.24 (men); and ß = 0.13 (women), ß = 0.14 (men), respectively). CONCLUSION: The 4-item CYFI proved to be a simple, practicable tool for routinely assessing key psychological attributes in spine surgery patients and made a relevant contribution in predicting postoperative outcome. CYFI's items were similar to those in the "STarT Back screening tool" used in primary care to triage patients into treatment pathways, further substantiating its validity. Wider use of CYFI may help improve the accuracy of predictive models derived using spine registry data.

Two-year outcome comparison of decompression in 14 lipomatosis cases with 169 degenerative lumbar spinal stenosis cases: a Swiss prospective multicenter cohort study.

PURPOSE: Spinal epidural lipomatosis (SEL) is defined as an abnormal and extensive accumulation of unencapsulated adipose tissue within the spinal epidural space. To date, there is a lack of high-level evidence studies reporting the outcome of surgical treatment of symptomatic SEL in patients with lumbar spinal stenosis (LSS). The aim was to compare clinical outcomes in patients with symptomatic LSS with and without SEL who underwent decompression surgery alone at the 12- and 24-month follow-up. METHODS: One hundred and eighty-three patients met the inclusion criteria, of which 14 had mainly SEL on at least one level operated in addition to possible degenerative changes on other levels and 169 degenerative LSS only. The main outcomes were pain (Spinal Stenosis Measure (SSM) symptoms), disability (SSM function), and quality of life [EQ-5D-3L summary index (SI)] at 24-month follow-up, and minimal clinically important difference (MCID) in SSM symptoms, SSM function, and EQ-5D-3L SI. RESULTS: The multiple regression linear models showed that SEL was associated with worse SSM symptoms (p = 0.045) and EQ-5D-3L SI scores (p = 0.026) at 24-month follow-up, but not with worse SSM function scores. Further, depression (in all models) was negatively associated with better clinical outcomes at 24-month follow-up. In the outcomes SSM symptoms and EQ-5D-3L SI, distinctly more patients in the classical LSS group reached MCID than in the SEL group (71.3% and 62.3% vs. 50.0% and 42.9%). CONCLUSIONS: Our study demonstrated that decompression alone surgery was associated with significant improvement in disability in both groups at 2 years, but not in pain and quality of life in patients with SEL.

The influence of endplate (Modic) changes on clinical outcomes in lumbar spinal stenosis surgery: a Swiss prospective multicenter cohort study.

PURPOSE: To investigate if the presence or absence of preoperative endplate Modic changes (MC) is predictive for clinical outcomes in degenerative lumbar spinal stenosis (DLSS) patients undergoing decompression-alone or decompression with instrumented fusion surgery. METHODS: Two hundred five patients were included and categorized into four groups; 102 patients into the decompression-alone group with MCs, 41 patients into the fusion group with MCs, 46 patients into the decompression-alone group without MCs, and 16 patients into the fusion group without MCs. Clinical outcome was quantified with changes in spinal stenosis measure (SSM) symptoms, SSM function, NRS pain, and EQ-5D-3L sum score over time (measured at baseline, 12-, 24-, and 36-month follow-up) and minimal clinically important difference (MCID) in SSM symptoms, SSM function, and NRS pain from baseline to 36-month follow-up. To investigate if possible effects of MCs had been modified or hidden by confounding variables, we used the group LASSO method to search for good prognostic models. RESULTS: There were no obvious differences in any of the clinical outcome measures between groups at baseline. At 12 months, most patients have improved in all outcomes and maintained improved conditions over time (no significant group differences). Between 70 and 90 percent of the patients maintained a clinically important improvement up to 36 months. CONCLUSIONS: Endplate MCs have no significant influence on clinical outcome parameters in patients with lumbar spinal stenosis compared to patients without MCs, independent of the chosen surgical strategy. All patients benefitted from surgical therapy up to 36-month follow-up. These slides can be retrieved under Electronic Supplementary Material.

Evaluating the Minimal Clinically Important Difference of EQ-5D-3L in Patients With Degenerative Lumbar Spinal Stenosis: A Swiss Prospective Multicenter Cohort Study.

STUDY DESIGN: Analysis of a prospective, multicenter cohort study. OBJECTIVE: The aim of our study was to compare thresholds of published minimal clinically important differences (MCID) for the three-level EuroQol-5D health survey (EQ-5D-3L) summary index (range -0.53 to 1.00) with our anchor-based estimate and evaluate how useful these thresholds are in determining treatment success in patients undergoing surgery for degenerative lumbar spinal stenosis (DLSS). SUMMARY OF BACKGROUND DATA: MCID values for EQ-5D-3L are specific to the underlying disease and only three studies have been published for DLSS patients reporting different values. METHODS: Patients of the multicenter Lumbar Stenosis Outcome Study with confirmed DLSS undergoing first-time decompression or fusion surgery with 12-month follow-up were enrolled in this study. To calculate MCID we used the Spinal Stenosis Measure satisfaction subscale as anchor. RESULTS: For this study, 364 patients met the inclusion criteria; of these, 196 were very satisfied, 72 moderately satisfied, 43 somewhat satisfied, and 53 unsatisfied 12 months after surgery. The MCID calculation estimated for EQ-5D-3L a value of 0.19. Compared with published MCID values (ranging from 0.30 to 0.52), our estimation is less restrictive. CONCLUSIONS: In patients with LSS undergoing surgery, we estimated an MCID value for EQ-5D-3L summary index of 0.19 with the help of the average change anchor-based method, which we find to be the most suitable method for assessing patient change scores. LEVEL OF EVIDENCE: 3.

What is the treatment effect of surgery compared with nonoperative treatment in patients with lumbar spinal stenosis at 1-year follow-up?

Objective: The aim of this study was to obtain an unbiased causal treatment estimate of the between-group difference of surgery versus nonoperative treatment with respect to outcomes on quality of life, pain, and disability in patients with degenerative lumbar spinal stenosis (DLSS) 12 months after baseline. Methods: The authors included DLSS patients from a large prospective multicenter observational cohort study. Propensity score matching was used, including 15 demographic, clinical, and MRI variables. Linear and logistic mixed-effects regression models were applied to quantify the between-group treatment effect. Unmeasured confounding was addressed in a sensitivity analysis, assessing the robustness of the results. Results: A total of 408 patients were included in this study, 222 patients after matching, with 111 in each treatment group. Patients with nonoperative treatment had lower quality of life at the 12-month follow-up (−6.21 points, 95% CI −9.93 to −2.49) as well as lower chances of reaching a minimal clinically important difference in Spinal Stenosis Measure (SSM) symptoms (OR 0.26, 95% CI 0.13 to 0.53) and SSM function (OR 0.26, 95% CI 0.14 to 0.49), than patients undergoing surgery. These results were very robust in case of unmeasured confounding. The surgical complication rate was low; 5 (4.5%) patients experienced a durotomy during intervention, and 5 (4.5%) patients underwent re-decompression. Conclusions: The authors used propensity score matching to assess the difference in treatment efficacy of surgery compared with nonoperative treatment in elderly patients with DLSS. This study delivers strong evidence that surgical treatment is superior to nonoperative treatment. It helps in clinical decision-making, especially when patients suffer for a long time, sometimes over many years, hoping for a spontaneous improvement of their symptoms. In light of these new results, the number of years with disability can hopefully be reduced by providing adequate treatment at the right time for this ever-growing elderly and frail population. Abbreviations: DLSS = degenerative lumbar spinal stenosis; HADS = Hospital Anxiety and Depression Scale; ITT = intention-to-treat; LSOS = Lumbar Stenosis Outcome Study; MCID = minimal clinically important difference; RCT = randomized controlled trial; SMD = standardized mean difference; SSM = Spinal Stenosis Measure.

Outcome of unilateral versus standard open midline approach for bilateral decompression in lumbar spinal stenosis: is "over the top" really better? A Swiss prospective multicenter cohort study.

OBJECTIVEIn this retrospective analysis of a prospective multicenter cohort study, the authors assessed which surgical approach, 1) the unilateral laminotomy with bilateral spinal canal decompression (ULBD; also called "over the top") or 2) the standard open bilateral decompression (SOBD), achieves better clinical outcomes in the long-term follow-up. The optimal surgical approach (ULBD vs SOBD) to treat lumbar spinal stenosis remains controversial.METHODSThe main outcomes of this study were changes in a spinal stenosis measure (SSM) symptoms score, SSM function score, and quality of life (sum score of the 3-level version of the EQ-5D tool [EQ-5D-3L]) over time. These outcome parameters were measured at baseline and at 12-, 24-, and 36-month follow-ups. To obtain an unbiased result on the effect of ULBD compared to SOBD the authors used matching techniques relying on propensity scores. The latter were calculated based on a logistic regression model including relevant confounders. Additional outcomes of interest were raw changes in main outcomes and in the Roland and Morris Disability Questionnaire from baseline to 12, 24, and 36 months.RESULTSFor this study, 277 patients met the inclusion criteria. One hundred forty-nine patients were treated by ULBD, and 128 were treated by SOBD. After propensity score matching, 128 patients were left in each group. In the matched cohort, the mean (95% CI) estimated differences between ULBD and SOBD for change in SSM symptoms score from baseline to 12 months were -0.04 (-0.25 to 0.17), to 24 months -0.07 (-0.29 to 0.15), and to 36 months -0.04 (-0.28 to 0.21). For change in SSM function score, the estimated differences from baseline to 12 months were 0.06 (-0.08 to 0.21), to 24 months 0.08 (-0.07 to 0.22), and to 36 months 0.01 (-0.16 to 0.17). Differences in changes between groups in EQ-5D-3L sum scores were estimated to be -0.32 (-4.04 to 3.40), -0.89 (-4.76 to 2.98), and -2.71 (-7.16 to 1.74) from baseline to 12, 24, and 36 months, respectively. None of the group differences between ULBD and SOBD were statistically significant.CONCLUSIONSBoth surgical techniques, ULBD and SOBD, may provide effective treatment options for DLSS patients. The authors further determined that the patient outcome results for the technically more challenging ULBD seem not to be superior to those for the SOBD even after 3 years of follow-up.

The impact and value of uni- and multimodal intraoperative neurophysiological monitoring (IONM) on neurological complications during spine surgery: a prospective study of 2728 patients.

PURPOSE: We compared the value of different uni- and multimodal intraoperative neurophysiological monitoring (IONM) methods on the detection of neurological complications during spine surgery. METHODS: IONM data derived from sensory spinal and cortical evoked potentials combined with continuous electromyography monitoring, motor evoked potentials and spinal recording were evaluated in relation to subsequent post-operative neurological changes. Patients were categorised based on their true-positive or true-negative post-operative neurological status. RESULTS: In 2728 consecutive patients we had 909 (33.3%) IONM alerts. We had 8 false negatives (0.3%) with post-operative radicular deficit that completely recovered within 3 months, except for one. There was no false negative for spinal cord injury. 107 were true positives, and 23 were false positives. Multimodal IONM sensitivity and specificity were 93.0% and 99.1%, respectively. The frequency of neurological complications including minor deficits was 4.2% (n = 115), of which 0.37% (n = 10) were permanent. Analysis of the single IONM modalities varied between 13 and 81% to detect neurological complications compared with 93% when using all modalities. CONCLUSION: Multimodal IONM is more effective and accurate in assessing spinal cord and nerve root function during spine surgeries to reduce both neurological complications and false-negative findings compared to unimodal monitoring. We recommend multimodal IONM in all complex spine surgeries. These slides can be retrieved from Electronic Supplementary Material.

Prognostic function to estimate the probability of meaningful clinical improvement after surgery - Results of a prospective multicenter observational cohort study on patients with lumbar spinal stenosis.

BACKGROUND: Approximately two thirds of patients with lumbar spinal stenosis (LSS) who undergo surgical treatment benefit from the surgery. The objective of this study was to derive a prognostic probability function (PPF) to identify patients with a high probability of post-surgical improvement because there is currently no method available. METHODS: In this multicenter, prospective, observational study, we collected data from eight medical centers in Switzerland in which patients underwent surgery for LSS. The endpoints were meaningful clinically important differences (MCID) in pain and disability one year after baseline. We developed a PPF named PROCESS (PostopeRative OutComE Spinal Stenosis), based on a large set of prognostic indicators extracted from the literature. The PPF was derived using data from a random subset of two thirds of the patients and validated in the remaining third. We addressed overfitting by shrinking the regression coefficients. The area under the ROC curve (AUC) and calibration determined the accuracy of the PPF. RESULTS: In this study, 452 LSS patients received surgery. 73% of the 300 patients in the derivation subset reached an MCID in pain and 68% reached an MCID in disability. The corresponding values were 70% and 63% in the validation subset, respectively. In the derivation subsample, the AUC was 0.64 (95% CI 0.57 to 0.71) for of the PPF predicting MCID in pain and 0.71 (0.64 to 0.77) for MCID in disability, after shrinkage. The corresponding numbers were 0.62 (0.52 to 0.72) and 0.70 (0.60 to 0.79) in the validation subsample, and the PPF showed good calibration. CONCLUSIONS: Surgical treatment for patients with lumbar spinal stenosis is being performed with increasing frequency. PROCESS is conditional on the individual pattern of preoperatively available prognostic indicators, and may be helpful for clinicians in counselling patients and in guiding the discussion on individual treatment decision in the era of personalized medicine.

Does Preoperative Degenerative Spondylolisthesis Influence Outcome in Degenerative Lumbar Spinal Stenosis? Three-Year Results of a Swiss Prospective Multicenter Cohort Study.

BACKGROUND: Decompression alone to treat degenerative lumbar stenosis with and without concomitant degenerative spondylolisthesis (DS; non-DS) has shown ambiguous results in the literature. OBJECTIVE: The aim is to compare clinical outcomes in DS and non-DS patients with lumbar stenosis who underwent decompression alone surgery without fusion on 1-3 adjacent levels after 6-month, 12-month, 24-month, and 36-month follow-up. METHODS: We conducted a prospective cohort study at 8 medical centers. The main outcomes of this study are changes in Spinal Stenosis Measure (SSM) symptoms score, SSM function score, and quality of life (EQ-5D-3L sum score) over time. Propensity score matching for DS versus non-DS was applied. RESULTS: One hundred seventy-seven patients met the inclusion criteria, 68 of whom had DS. In the matched cohort (n = 136), the estimated difference in SSM symptoms score of DS versus non-DS for changes from baseline to 36 months was 0.21 (95% CI, -0.15 to 0.57). For SSM function score, the estimated difference from baseline to 36 months was 0.05 (-0.21 to 0.31). Differences in changes between groups in EQ-5D-3L sum score were estimated to be -3.66 (-10.63 to 3.31) from baseline to 36 months. None of the group differences between the non-DS and the DS group was statistically significant. All matched patients improved over time in all additional outcomes. CONCLUSIONS: Even after 3 years of follow-up, we show that among patients with degenerative lumbar spinal stenosis, both groups (DS and non-DS) distinctively take advantage of decompression alone without fusion.

Influence of Paravertebral Muscle Quality on Treatment Efficacy of Epidural Steroid Infiltration or Surgical Decompression in Lumbar Spinal Stenosis-Analysis of the Lumbar Spinal Outcome Study (LSOS) Data: A Swiss Prospective Multicenter Cohort Study.

STUDY DESIGN: Prospective multicenter cohort study. OBJECTIVE: To study the question whether paravertebral muscle quality may affect the clinical outcome of epidural steroid infiltration (ESI) or surgical decompression in patients with symptomatic lumbar spinal stenosis (LSS). SUMMARY OF BACKGROUND DATA: To the present, the impact of paravertebral muscle quality on clinical outcome of ESI or surgical decompression in patients with LSS has not been clarified. METHODS: The Lumbar Stenosis Outcome Study was used as database. Patients with symptomatic LSS who received an ESI (group I) or lumbar decompression surgery (group II), had a follow-up of at least 12 months and a pretreatment lumbar magnetic resonance imaging were included (n = 205). Paravertebral muscle quality was quantified by the degree of fatty degeneration (according to Goutallier) on the level L3. Clinical outcome was assessed using the Spinal Stenosis Measure, Numeric Rating Scale, Roland and Morris Disability Questionnaire, and EQ-5D-3L sum score. Reinfiltration, surgery following infiltration, or revision was defined as treatment failure. RESULTS: ESI (group I) and surgical treatment (group II) were associated with a failure rate of 60% and 12.7%, respectively. In group I, there was a tendency for the rate of reintervention to be less in patients with bad muscle quality (P = 0.22). In group II, improvements in the clinical outcomes up to 12 months did not differ between Goutallier stage ≤1 and ≥2. Patients with Goutallier stage ≤1 had more improvement in Spinal Stenosis Measure symptoms (P = 0.04). CONCLUSION: Relevant fatty degeneration of the paravertebral musculature, as a sign of low muscle quality, has low impact on clinical outcome and the high failure rates with conservative treatment by ESI compared to surgical decompression. Therefore fatty degeneration has no relevant prognostic value for LSS treatment. LEVEL OF EVIDENCE: 2.

Decompression Surgery Alone Versus Decompression Plus Fusion in Symptomatic Lumbar Spinal Stenosis: A Swiss Prospective Multicenter Cohort Study With 3 Years of Follow-up.

STUDY DESIGN: Retrospective analysis of a prospective, multicenter cohort study. OBJECTIVE: To estimate the added effect of surgical fusion as compared to decompression surgery alone in symptomatic lumbar spinal stenosis patients with spondylolisthesis. SUMMARY OF BACKGROUND DATA: The optimal surgical management of lumbar spinal stenosis patients with spondylolisthesis remains controversial. METHODS: Patients of the Lumbar Stenosis Outcome Study with confirmed DLSS and spondylolisthesis were enrolled in this study. The outcomes of this study were Spinal Stenosis Measure (SSM) symptoms (score range 1-5, best-worst) and function (1-4) over time, measured at baseline, 6, 12, 24, and 36 months follow-up. In order to quantify the effect of fusion surgery as compared to decompression alone and number of decompressed levels, we used mixed effects models and accounted for the repeated observations in main outcomes (SSM symptoms and SSM function) over time. In addition to individual patients' random effects, we also fitted random slopes for follow-up time points and compared these two approaches with Akaike's Information Criterion and the chi-square test. Confounders were adjusted with fixed effects for age, sex, body mass index, diabetes, Cumulative Illness Rating Scale musculoskeletal disorders, and duration of symptoms. RESULTS: One hundred thirty-one patients undergoing decompression surgery alone (n = 85) or decompression with fusion surgery (n = 46) were included in this study. In the multiple mixed effects model the adjusted effect of fusion compared with decompression alone surgery on SSM symptoms was 0.06 (95% confidence interval: -0.16-0.27) and -0.07 (95% confidence interval: -0.25-0.10) on SSM function, respectively. CONCLUSION: Among the patients with degenerative lumbar spinal stenosis and spondylolisthesis our study confirms that in the two groups, decompression alone and decompression with fusion, patients distinctively benefited from surgical treatment. When adjusted for confounders, fusion surgery was not associated with a more favorable outcome in both SSM scores as compared to decompression alone surgery. LEVEL OF EVIDENCE: 3.