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It is unclear whether outcome measures used in degenerative lumbar spinal stenosis (DLSS) have been validated for this condition. Cross-sectional analysis of studies for DLSS included in systematic reviews (SA) and meta-analyses (MA) indexed in the Cochrane Library. We extracted all outcome measures for pain and disability. We assessed whether the studies provided external references for the validity of the outcome measures and the quality of the validation studies. Out of 20 SA/MA, 95 primary studies used 242 outcome measures for pain and/or disability. Most commonly used were the VAS (n = 69), the Oswestry Disability Index (n = 53) and the Zurich Claudication Questionnaire (n = 22). Although validation references were provided in 45 (47.3%) primary studies, only 14 validation studies for 9 measures (disability n = 7, pain and disability combined n = 2) were specifically validated in a DLSS population. The quality of the validation studies was mainly poor. The Zurich Claudication Questionnaire was the only disease specific tool with adequate validation for assessing treatment response in DLSS. To compare results from clinical studies, outcome measures need to be validated in a disease specific population. The quality of validation studies need to be improved and the validity in studies adequately cited., (© 2023. The Author(s).)

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 (β, 0.171; 95% CI, 0.047-0.295; P = .007) and lower EQ-5D-3L summary index scores (β, -0.061; 95% CI, -0.105 to -0.017; P = .007) but not with higher SSM physical function scores (β, 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.

Evidence on the role of depression and anxiety in patients undergoing surgical treatment for symptomatic degenerative lumbar spinal stenosis (DLSS) is conflicting. We aimed to assess the association between depression and anxiety with symptoms and function in patients undergoing surgery for DLSS. Included were patients with symptomatic DLSS participating in a prospective multicentre cohort study who underwent surgery and completed the 24-month follow-up. We used the hospital anxiety and depression scale (HADS) to assess depression/anxiety. We used mixed-effects models to quantify the impact on the primary outcome change in the spinal stenosis measure (SSM) symptoms/function subscale from baseline to 12- and 24-months. Logistic regression analysis was used to quantify the odds of the SSM to reach a minimal clinically important difference (MCID) at 24 months follow-up. The robustness of the results in the presence of unmeasured confounding was quantified using a benchmarking method based on a multiple linear model. Out of 401 patients 72 (17.95%) were depressed and 80 anxious (19.05%). Depression was associated with more symptoms (β = 0.36, 95% confidence interval (CI) 0.20 to 0.51, p < 0.001) and worse function (β = 0.37, 95% CI 0.24 to 0.50, p < 0.001) at 12- and 24-months. Only the association between baseline depression and SSM symptoms/function was robust at 12 and 24 months. There was no evidence for baseline depression/anxiety decreasing odds for a MCID in SSM symptoms and function over time. In patients undergoing surgery for symptomatic DLSS, preoperative depression but not anxiety was associated with more severe symptoms and disability at 12 and 24 months., (© 2022. The Author(s).)

Aims of the Study: Mobility disability due to spinal stenosis is common in the senior population and often surgery is warranted for patients with severe symptoms and neurological dysfunction. However, although current clinical guidelines recommend stabilisation surgery in addition to decompression in patients with spinal stenosis and instability due to degenerative spondylolisthesis, the relationship between outcomes and the specific type of surgery have not been well studied. We therefore assessed the postoperative recovery timeline for 12 months and compared patient-reported outcomes dependent on the extent of decompression and additional stabilisation among seniors undergoing spinal stenosis surgery., Methods: We investigated 457 patients (mean age 76.0 &plusmn; 10.7 years, 58% women) from a consecutive cohort prior to spinal stenosis surgery. Follow-up was at 3 or 6months and at 12 months postoperatively. At each visit, pain, neurological dysfunction and disability were assessed using the North American Spine Society questionnaire. Repeated-measures analysis compared outcomes by type of surgery adjusting for baseline symptoms, gender, age, number of comorbidities, centre and year of surgery., Results: Most improvement occurred within the first 3 to 6 months with little or no further improvement at 12 months. Over 12 months and in adjusted models, patients receiving one-segment versus multi-segment decompression experienced significantly greater reduction of pain (&minus;49.2% vs &minus;41.9%, p = 0.013) and neurological dysfunction (&minus;37.1% vs &minus;25.9%, p &lt;0.0001), but only borderline greater reduction of disability (&minus;32.7% vs &minus;28.2%, p = 0.051). Moreover, reduction in pain and neurological function did not differ with or without additional stabilisation and extend of decompression. However, patients who received one-segment (&minus;28.9%) or multi-segment (&minus;28.3%) stabilisation experienced significantly less reduction in disability after surgery compared with those who were not stabilised (&minus;34.1%, p &lt;0.043)., Conclusions: Among senior patients undergoing spinal stenosis surgery, recovery was largely complete by 3 to 6 months after surgery and differed little by type of surgery independently of symptoms prior to surgery and other covariates. However we could document a trend toward more improvement in particularly neurological dysfunction and disability with less invasive surgery.

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.

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.

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.

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.

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., Competing Interests: The authors have declared that no competing interests exist.

Objective: To investigate whether upright radiographs can predict lumbar spinal canal stenosis using supine lumbar magnetic resonance imaging (MRI) and to investigate the detection performance for spondylolisthesis on upright radiographs compared with supine MRI in patients with suspected lumbar spinal canal stenosis (LSS)., Materials and Methods: In this retrospective study, conventional radiographs and MR images of 143 consecutive patients with suspected LSS (75 female, mean age 72 years) were evaluated. The presence and extent of listhesis (median ± interquartile range) were assessed on upright radiographs and supine MRI of L4/5. In addition, the grade of central spinal stenosis of the same level was evaluated on MRI according to the classification of Schizas and correlated with the severity/grading of anterolisthesis on radiographs., Results: Anterolisthesis was detected in significantly more patients on radiographs (n = 54; 38%) compared with MRI (n = 28; 20%), p < 0.001. Pairwise comparison demonstrated a significantly larger extent of anterolisthesis on radiographs (9 ± 5 mm) compared with MRI (5 ± 3 mm), p < 0.001. A positive correlation was found regarding the extent of anterolisthesis measured on radiographs and the grade of stenosis on MRI (r = 0.563, p < 0.001). Applying a cutoff value of ≥5 mm anterolisthesis on radiographs results in a specificity of 90% and a positive predictive value of 78% for the detection of patients with LSS, as defined by the Schizas classification., Conclusion: Upright radiographs demonstrated more and larger extents of anterolisthesis compared with supine MRI. In addition, in patients with suspected LSS, the extent of anterolisthesis on radiographs (particularly ≥5 mm) is indicative of LSS and warrants lumbar spine MRI.

Study Design: A prospective multicenter cohort study., Objectives: This study evaluates the risk for surgical site infections (SSIs) or wound healing problems (WHPs) in patients who underwent corticosteroid injection before lumbar decompression surgery., Summary of Background Data: Corticosteroid injections are often used for the treatment of the degenerated spine. However, their well-known immunosuppressive effects could increase the risk for local infections, particularly if a surgical intervention follows the injection rapidly., Methods: The Swiss Lumbar Stenosis Outcome Study (LSOS), which is a prospective multicenter cohort study of patients with symptomatic lumbar spinal stenosis, was used as database. Of 743 patients, 422 patients underwent surgery and were eligible for the study. Ten patients (2.4%) were revised for either SSIs (n = 6) or WHPs (n = 4). A control group (n = 19) was constructed matched according to age, sex, diabetes, and body mass index (BMI). Odds ratios (ORs) were calculated by using a conditional logistic regression model to quantify the risk of SSI or WHP after preoperative corticosteroid injection. Subgroup analysis was performed for patients with injection within 0 to 3 months before surgery, 0 to 6 months before surgery, or any injection at all before surgery., Results: Within this cohort, no significant association could be found between preoperative corticosteroid injection and postoperative SSI or WHP in patients with corticosteroid injections within 0 to 3 months before surgery [OR = 0.36, 95% confidence interval (95% CI) 0.04-3.22], 0 to 6 months before surgery (OR = 0.69 95% CI 0.14-3.49), or any time before surgery (OR = 0.43, 95% CI 0.04-3.22)., Conclusion: Within the here investigated cohort, the risk of SSIs or WHPs following lumbar spinal decompression surgery seems not highly associated with preoperative corticosteroid injections. However, the safe time interval between corticosteroid infiltrations and surgery remains unknown, should not be decreased incautiously, and is the subject of further research., Level of Evidence: 2.

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., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Purpose: To assess the performance of fat-suppressed fluid-sensitive MRI sequences compared to T1-weighted (T1w) / T2w sequences for the detection of Modic 1 end-plate changes on lumbar spine MRI., Materials and Methods: Sagittal T1w, T2w, and fat-suppressed fluid-sensitive MRI images of 100 consecutive patients (consequently 500 vertebral segments; 52 female, mean age 74 ± 7.4 years; 48 male, mean age 71 ± 6.3 years) were retrospectively evaluated. We recorded the presence (yes/no) and extension (i. e., Likert-scale of height, volume, and end-plate extension) of Modic I changes in T1w/T2w sequences and compared the results to fat-suppressed fluid-sensitive sequences (McNemar/Wilcoxon-signed-rank test)., Results: Fat-suppressed fluid-sensitive sequences revealed significantly more Modic I changes compared to T1w/T2w sequences (156 vs. 93 segments, respectively; p < 0.001). The extension of Modic I changes in fat-suppressed fluid-sensitive sequences was significantly larger compared to T1w/T2w sequences (height: 2.53 ± 0.82 vs. 2.27 ± 0.79, volume: 2.35 ± 0.76 vs. 2.1 ± 0.65, end-plate: 2.46 ± 0.76 vs. 2.19 ± 0.81), (p < 0.05). Modic I changes that were only visible in fat-suppressed fluid-sensitive sequences but not in T1w/T2w sequences were significantly smaller compared to Modic I changes that were also visible in T1w/T2w sequences (p < 0.05)., Conclusion: In conclusion, fat-suppressed fluid-sensitive MRI sequences revealed significantly more Modic I end-plate changes and demonstrated a greater extent compared to standard T1w/T2w imaging., Key Points: · When the Modic classification was defined in 1988, T2w sequences were heavily T2-weighted and thus virtually fat-suppressed.. · Nowadays, the bright fat signal in T2w images masks edema-like changes.. · The conventional definition of Modic I changes is not fully applicable anymore.. · Fat-suppressed fluid-sensitive MRI sequences revealed more/greater extent of Modic I changes.., Citation Format: · Finkenstaedt T, Del Grande F, Bolog N et al. Modic Type 1 Changes: Detection Performance of Fat-Suppressed Fluid-Sensitive MRI Sequences. Fortschr Röntgenstr 2018; 190: 152 - 160., Competing Interests: Disclosure The authors report no conflicts of interest in this work., (© Georg Thieme Verlag KG Stuttgart · New York.)

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.

Study Design: This is prospective multicenter cohort study., Objective: To assess whether patients with confirmed multisegmental lumbar spinal stenosis benefit more from a single-level or a multilevel decompression., Summary of Background Data: In multisegmental lumbar spinal stenotic cases, the decision as to how many levels of stenosis need to be operated to achieve the best possible clinical outcome is still unknown and remains a controversy between spine surgeons., Materials and Methods: Patients of the Swiss Lumbar Stenosis Outcome Study (LSOS) with confirmed multisegmental LSS undergoing first-time decompression without fusion were enrolled in this study. The main outcomes of this study were Spinal Stenosis Measure (SSM) symptoms and function over time, measured at baseline, 6, 12, and 24 months follow-up. Further outcomes of interest were changes in SSM, numeric rating scale, feeling thermometer, the EQ-5D-EL, and the Roland and Morris disability questionnaire from baseline to 6, 12, and 24 months., Results: After 12 months, a total of 141 patients met the inclusion criteria; of these, 33 (23%) underwent a single-level and 108 (77%) a multilevel decompression. Multilevel decompression was associated with a significantly less favorable SSM symptoms and function score, respectively, as compared with single-level decompression. In all further outcomes of interest single-level as well as multilevel patients improved over time., Conclusions: Our study showed that in multisegmental stenotic cases a single-level decompression was associated with a significantly more favorable SSM symptoms and function score, respectively, as compared with multilevel decompression. This study provides evidence that in multisegmental stenotic cases a single-level decompression might be sufficient to improve patient's symptoms and function.

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.

Study Design: Prospective multicenter cohort study., Objective: To evaluate the effect of pre- and postoperatively assessed fear avoidance beliefs (FAB) on pain and disability in patients with degenerative lumbar spinal stenosis (LSS) after decompression surgery., Summary of Background Data: To the present, the influence of pre- and postoperative FAB on the prognosis after surgery for LLS is still unclear., Methods: Patients of the Swiss Lumbar Stenosis Outcome Study (LSOS) with confirmed LSS undergoing first-time decompression without fusion were enrolled in this study. The main outcome of this study was minimal clinically important difference (MCID) in spinal stenosis measure symptoms (pain) and function (disability) after 12 months. To analyze the influence of pre- and postoperatively assessed FAB on pain and disability we built simple and multiple logistic regression models., Results: In this analysis of 234 patients undergoing decompression surgery for symptomatic degenerative LSS we found baseline FAB measured by the FAB physical activity subscale (FABQ-P) not to be associated with pain (OR 0.95; 95% CI: 0.55-1.67) and disability (OR 1.11; 95% CI: 0.64-1.92) at 12 months' follow-up. In the final multiple logistic regression models patients with high FABQ-P at 6 months (OR 0.46; 95% CI: 0.24-0.91) and high persistent FABQ-P at baseline and 6 months (OR 0.34, 95% CI: 0.16-0.73) were less likely to report a MCID for spinal stenosis measure symptoms at 12 months. Our analysis found a similar trend for disability; however, the results were not statistically significant., Conclusion: In elderly patients undergoing decompression surgery for symptomatic degenerative LSS preoperative fear avoidance beliefs were not a prognostic indicator for the outcome. Patients with FAB at 6 months and persistent FAB were less likely to experience clinically relevant improvement in pain at 12 months. Studies should address the importance of persistent postoperative FAB., Level of Evidence: 3.

Purpose: Patients enrolled in clinical studies typically represent a sub-set of all who are eligible, and selection bias may compromise the generalizability of the findings. Using Registry data, we evaluated whether surgical patients recruited by one of the referring centres into the Lumbar Spinal Stenosis Outcome Study (LSOS; a large-scale, multicentre prospective observational study to determine the probability of clinical benefit after surgery) differed in any significant way from those who were eligible but not enrolled., Methods: Data were extracted for all patients with lumbar spinal stenosis registered in our in-house database (interfaced to Eurospine's Spine Tango Registry) from 2011 to 2013. Patient records and imaging were evaluated in relation to the admission criteria for LSOS to identify those who would have been eligible for participation but were not enrolled (non-LSOS). The Tango surgery data and Core Outcome Measures Index (COMI) data at baseline and 3 and 12 months after surgery were analysed to evaluate the factors associated with LSOS enrolment or not., Results: 514 potentially eligible patients were identified, of which 94 (18%) were enrolled into LSOS (range 2-48% for the 6 spine surgeons involved in recruiting patients) and 420 (82%) were not; the vast majority of the latter were due to non-referral to the study by the surgeon, with only 5% actually refusing participation. There was no significant difference in gender, age, BMI, smoking status, or ASA score between the two groups (p ≥ 0.18). Baseline COMI was significantly (p = 0.002) worse in the non-LSOS group (7.4 ± 1.9) than the LSOS group (6.7 ± 1.9). There were no significant group differences in any Tango surgery parameters (additional spine patholothegies, operation time, blood loss, complications, etc.) although significantly more patients in the non-LSOS group had a fusion procedure (38 vs 18% in LSOS; p = 0.0004). Postoperatively, neither the COMI nor its subdomain scores differed significantly between the groups (p > 0.05). Multiple logistic regression revealed that worse baseline COMI (p = 0.021), surgeon (p = 0.003), and having fusion (p = 0.014) predicted non-enrolment in LSOS., Conclusion: A high proportion of eligible patients were not enrolled in the study. Non-enrolment was explained in part by the specific surgeon, worse baseline COMI status, and having a fusion. The findings may reflect a tendency of the referring surgeon not to overburden more disabled patients and those undergoing more extensive surgery with the commitments of a study. Beyond these factors, non-enrolment appeared to be somewhat arbitrary, and was likely related to surgeon forgetfulness, time constraints, and administrative errors. Researchers should be aware of potential selection bias in their clinical studies, measure it (where possible) and discuss its implications for the interpretation of the study's findings.

Purpose: To assess the inter- and intra-reader agreement of commonly used quantitative and qualitative image parameters for the assessment of degenerative lumbar spinal canal stenosis (LSS) by magnetic resonance imaging (MRI)., Methods: In this ethical board approved cross-sectional multicenter study, MRI of 100 randomly selected patients (median age 72.5 years, 48 % female) of the prospective Lumbar Stenosis Outcome Study (LSOS) were evaluated by two independent readers. A set of five previously published core imaging parameters as well as nine qualitative and five quantitative additional parameters regarding LSS and degenerative changes of the lumbar spine were assessed to calculate κ and intraclass correlation coefficients (ICC) for the inter-reader agreement. Additional repeated image evaluations were performed by one reader to calculate the intra-reader agreement., Results: κ values for the core image parameters ranged between 0.42 (compromise of the foraminal zone) and 0.77 (relation between fluid and cauda equina) for inter-reader agreement and between 0.59 (compromise of the foraminal zone) and 0.8 (compromise of the central zone) for intra-reader agreement. The inter-reader agreement for the non-core parameters showed κ values of 0.27-0.69 and ICC values of 0.46-0.85. The intra-reader agreement showed κ values of 0.53-0.69 and ICC values of 0.81-0.88., Conclusions: The inter- and intra-reader agreement of commonly used quantitative and qualitative image parameters for the assessment of LSS showed quite a variability with previously defined core parameters having good to excellent inter- and intra-reader agreements.

Purpose: Patient-reported outcome measures (PROM) are used to measure treatment efficacy in clinical trials. The impact of the choice of a PROM and the cut-off values for 'meaningful important differences' (MID) on the study results in patients with lumbar spinal stenosis (LSS) is unclear., Objective: The objective is to study the consequences of applying different PROMs and values for MID for pain and disability on the proportions of patients with improvement., Design: Prospective multi-center cohort study., Methods: Proportions of patients with improvement using established MID cut-off values were calculated and compared for PROMs for pain and disability., Results: 466 patients with LSS completed a baseline and 6-month follow-up assessment and were analyzed. Treatment modalities included surgery (65 %), epidural steroid injections (15 %), or conservative care (20 %). The prevalence of patients fulfilling the criteria for MID ranged from 40 to 70 % across all outcome measures and cut-offs. The agreement of the spinal stenosis outcome measure (SSM) symptom subscale with other pain scales, and the SSM function subscale with other function scales was fair to moderate (Cohen's κ value between 0.24 and 0.5). Disagreement in the assessment of MID (MID reported by patients in one scale but not the other) was found in at least one-third of the patients., Conclusion: The MID in outcome scores for this population varied from 40 to 70 %, depending on the measure or cut-off score used. Further, the disagreement between domain specific measures indicates that differences between studies may be also related to the choice of an outcome measures. An international consensus on the use and reporting of outcome measures in studies on lumbar spinal stenosis is needed.

Purpose: To evaluate the cost-effectiveness of conservative versus surgical treatment strategies for lumbar spinal stenosis (LSS)., Methods: Patients prospectively enrolled in the multicenter Lumbar Stenosis Outcome Study (LSOS) with a minimum follow-up of 12 months were included. Quality adjusted life years (QALY) were calculated based on EQ-5D data. Cost data were retrieved retrospectively. Cost-effectiveness was calculated via decision tree analysis., Results: A total of 434 patients were included, treated surgically (n = 170) or conservatively (n = 264) for LSS. The majority of surgically treated patients underwent decompression (n = 141, 82.9%), and 17.1% (n = 29) additionally underwent fusion. A reoperation was required in 13 (7.6%) surgically treated patients. In 27 (10.2%) conservatively treated patients, a single infiltration was successful, with no further infiltration or surgery within the follow-up. However, 46 patients (17.4%) required multiple infiltrations, and in 191 (72.4%) initially conservatively treated patients a subsequent surgery was needed. The area under the curve was 0.776 QALY in the surgical arm (0.776 and 0.790, decompression or additional fusion, respectively), compared to 0.778 in the conservative arm. Treatment costs were estimated at CHF 12,958 and 13,637 (USD 13,465 and 14,169) in surgically and initially conservatively treated patients, respectively [base-case incremental cost-effectiveness ratio (ICER): CHF 392,145, USD 407,831], per QALY gained. Probabilistic sensitivity analysis identified surgery as the preferred strategy in 67.1%., Conclusions: Both the surgical and the conservative treatment approach resulted in a comparable health-related quality of life within the first year after study inclusion. Due to slightly higher costs, mostly because the majority of initially conservatively treated patients underwent multiple infiltrations or a subsequent surgery, decompressive surgery was identified as the most cost-effective approach for LSS in this setting.

Study Design: A prospective multicenter cohort study., Objective: The aim of this study was to identify an association between pain and magnetic resonance imaging (MRI) parameters in patients with lumbar spinal stenosis (LSS)., Summary of Background Data: At present, the relationship between abnormal MRI findings and pain in patients with LSS is still unclear., Methods: First, we conducted a systematic literature search. We identified relationships of relevant MRI parameters and pain in patients with LSS. Second, we addressed the study question with a thorough descriptive and graphical analysis to establish a relationship between MRI parameters and pain using data of the LSS outcome study (LSOS)., Results: In the systematic review including four papers about the associations between radiological findings in the MRI and pain, the authors of two articles reported no association and two of them did. Of the latters, only one study found a moderate correlation between leg pain measured by Visual Analog Scale (VAS) and the degree of stenosis assessed by spine surgeons. In the data of the LSOS study, we could not identify a relevant association between any of the MRI parameters and buttock, leg, and back pain, quantified by the Spinal Stenosis Measure (SSM) and the Numeric Rating Scale (NRS). Even by restricting the analysis to the level of the lumbar spine with the most prominent radiological "stenosis," no relevant association could be shown., Conclusion: Despite a thorough analysis of the data, we were not able to prove any correlation between radiological findings (MRI) and the severity of pain. There is a need for innovative "methods/techniques" to learn more about the causal relationship between radiological findings and the patients' pain-related complaints., Level of Evidence: 2.

Background: Incidental durotomy is a well-known complication during surgery for degenerative lumbar spinal stenosis (DLSS). In this prospective multicenter cohort study including eight medical centers our aim was to assess whether incidental durotomy during first-time lumbar spinal stenosis decompression surgery without fusion has an impact on long-term outcome., Methods: Patients of the multi-center Lumbar Stenosis Outcome Study (LSOS) with confirmed DLSS undergoing first-time decompression without fusion were enrolled in this study. Baseline patient characteristics and outcomes were analyzed at 6, 12, and 24 months follow-up respectively with the Spinal Stenosis Measure (SSM), the Numeric Rating Scale (NRS), Feeling Thermometer (FT), the EQ-5D-EL, and the Roland and Morris Disability Questionnaire (RMDQ)., Results: A total of 167 patients met the inclusion criteria. Fifteen (9%) of those patients had an incidental durotomy. Baseline characteristics were similar between the durotomy and no-durotomy group. All patients improved over time. In the group of durotomy patients, the median improvement in SSM symptoms scale was 1.1 points at 6 months, 1.1 points at 12 months, and 1.6 points at 24 months after baseline. For the no-durotomy group, these improvements were 0.8, 0.9, and 0.9. For SSM function the improvements were 1.0, 0.8, and 0.9 in the durotomy group, and 0.6, 0.8, and 0.8 in the no-durotomy group. None of the between-group differences were statistically significant., Conclusions: Incidental durotomy in patients with DLSS undergoing first-time decompression surgery without fusion did not have negative effect on long-term outcome and quality of life. However, only 15 patients were included in the durotomy group but these findings remained even after adjusting for observed differences in baseline characteristics.

Study Design: Prospective, multicenter cohort study including 8 medical centers of the Cantons Zurich, Lucerne, and Thurgau, Switzerland., Objective: The aim of the study was to assess whether obese patients benefit after decompression surgery for degenerative lumbar spinal stenosis (DLSS)., Summary and Background Data: Lumbar decompression surgery has been shown to improve quality of life in patients with DLSS. In the existing literature, the efficacy of lumbar decompression in the obese population remains controversial., Methods: Baseline patient characteristics and outcomes were analyzed at 6 and 12 months follow-up with the Spinal Stenosis Measure (SSM), the Numeric Rating Scale (NRS), Feeling Thermometer (FT), the EQ-5D-EL, and the Roland and Morris Disability Questionnaire (RMDQ). Body mass index (BMI) was classified into 3 categories according to the WHO. Minimal clinically important differences (MCIDs) in SSM for different BMI categories were considered as main outcome., Results: Of the 656 patients in the Lumbar Spinal Outcome Study database as of end of October 2014, 166 patients met the inclusion criteria. Fifty (30.1%) had a BMI less than 25 (underweight and normal weight group), 72 (43.4%) had a BMI between 25 and less than 30 (preobesity group), and 44 (26.5%) patients had a BMI at least 30 (obese group). We found for the main outcome that in obese patients 36% reached MCID at 6 months, and 48% at 12 months. The estimated odds ratios for MCID in the obese group were 0.78 (0.34-1.82) at 6 months and 0.99 (0.44-2.23) at 12 months in a logistic regression model adjusting for levels of laminectomy. In the additional outcomes, SSM, NRS, FT, and RMDQ showed statistically significant mean improvements in the 6 and 12 months follow-up., Conclusion: Obese patients can expect clinical improvement after lumbar decompression for DLSS, but the percentage of patients with a meaningful improvement is lower than in the group of patients with underweight, normal weight, and preobese weight at 6 and 12 months.

Study Design: Retrospective analysis of data from patients participating in the Lumbar Spinal Stenosis Outcome Study (LSOS)., Objective: The aim of LSOS was to assess clinical outcomes after surgical or nonoperative treatment in patients with and without prior epidural steroid injections., Summary of Background Data: Epidural steroid injections (ESI), a common treatment modality, reduce symptoms in the short-term, but according to a subgroup analysis from the Spine Patient Outcomes Research Trial (SPORT) they reduce the amount of improvement after subsequent surgical or nonoperative treatment., Methods: The data of 281 patients with lumbar spinal stenosis who had completed baseline and 6-month follow-up assessments were analyzed. Patients completed the Spinal Stenosis Measure (SSM). Changes in the SSM scores from baseline to follow-up were compared between patients with and without prior ESI, for the surgical and nonsurgical treatment groups., Results: The mean (SD) age of the patients was 75 (8.7) years. 229 patients underwent surgery and 111 of these had received an ESI in the 12 months before surgery. Of the 52 patients treated nonoperatively, 29 had received a prior ESI. The unadjusted changes (improvement) in the SSM-symptom scores between baseline and 6 months' follow up were: surgery and prior ESI 0.95, surgery and no prior ESI 0.78 (P = 0.15); no surgery and prior ESI 0.28, no surgery and no prior ESI 0.29 (P = 0.85). When adjusted for confounding factors, the reduction in SSM-symptom score was greater for surgery than for nonoperative treatment by 0.41 points (P < 0.001); the effect of having had an ESI prior to study entry was -0.08 (P = 0.40)., Conclusion: The analysis of outcomes in the LSOS cohort provided no evidence that ESIs have a negative effect on the short-term outcome of surgery or nonoperative treatment in patients with lumbar spinal stenosis., Level of Evidence: 3.

Background: Lumbar spinal stenosis is the most common reason for spinal surgery in elderly patients. However, the surgical management of spinal stenosis is controversial. The aim of this review was to list aspects a surgeon considers when choosing a specific type of treatment., Methods: Appraisal of arguments reported in randomized controlled trials (RCTs) included in systematic reviews published or indexed in the Cochrane library studying surgical treatments in patients with spinal stenosis., Results: Eight out of nine RCTs listed arguments for the choice of their treatments under investigation. The argument for decompression alone was the high success rate, the argument against was a potential increase in vertebral instability. The argument for decompression and fusion without instrumentation was that it is a well-established technique with a high fusion success rate, the argument against it was that the indication for fusion in spinal stenosis has remained unclear. The argument for decompression and fusion with instrumentation was an increased fusion rate compared to decompression and fusion without instrumentation, the argument against this was that the invasive procedure is associated with more complications., Conclusions: The main argument identified in this appraisal for and against decompression alone in patient with lumbar spinal stenosis was whether or not instability should be treated with (instrumented) fusion procedures. However, there is disagreement on how instability should be defined. In a first step it is important that researchers and clinicians agree on definitions for important key concepts such as instability and reoperations.

Purpose: To define radiological criteria and parameters as a minimum standard in a structured radiological report for patients with lumbar spinal stenosis (LSS) and to identify criteria and parameters for research purposes., Material and Methods: All available radiological criteria and parameters for LSS were identified using systematic literature reviews and a Delphi survey. We invited to the consensus meeting, and provided data, to 15 internationally renowned experts from different countries. During the meeting, these experts reached consensus in a structured and systematic discussion about a core list of radiological criteria and parameters for standard reporting., Results: We identified a total of 27 radiological criteria and parameters for LSS. During the meeting, the experts identified five of these as core items for a structured report. For central stenosis, these were "compromise of the central zone" and "relation between fluid and cauda equina". For lateral stenosis, the group agreed that "nerve root compression in the lateral recess" was a core item. For foraminal stenosis, we included "nerve root impingement" and "compromise of the foraminal zone"., Conclusion: As a minimum standard, five radiological criteria should be used in a structured radiological report in LSS. Other parameters are well suited for research., Key Points: The five most important radiological criteria for standard clinical reporting were selected. The five most important quantitative radiological parameters for research purposes were selected. These core criteria could help standardize the communication between health care providers.

Purpose: To validate the German version of the spinal stenosis measure (SSM), a disease-specific questionnaire assessing symptom severity, physical function, and satisfaction with treatment in patients with lumbar spinal stenosis., Methods: After translation, cross-cultural adaptation, and pilot testing, we assessed internal consistency, test-retest reliability, construct validity, and responsiveness of the SSM subscales. Data from a large Swiss multi-center prospective cohort study were used. Reference scales for the assessment of construct validity and responsiveness were the numeric rating scale, pain thermometer, and the Roland Morris Disability Questionnaire., Results: One hundred and eight consecutive patients were included in this validation study, recruited from five different centers. Cronbach's alpha was above 0.8 for all three subscales of the SSM. The objectivity of the SSM was assessed using a partial credit approach. The model showed a good global fit to the data. Of the 108 patients 78 participated in the test-retest procedure. The ICC values were above 0.8 for all three subscales of the SSM. Correlations with reference scales were above 0.7 for the symptom and function subscales. For satisfaction subscale, it was 0.66 or above. Clinically meaningful changes of the reference scales over time were associated with significantly more improvement in all three SSM subscales (p < 0.001). Conclusion: The proposed version of the SSM showed very good measurement properties and can be considered validated for use in the German language.

Objective: The objective of our study was to perform a systematic review of the semiquantitative and qualitative radiologic criteria that are used for the diagnosis of lumbar spinal stenosis (LSS)., Materials and Methods: A four-step systematic literature search including the MEDLINE database was performed by an experienced librarian to reveal all semiquantitative or qualitative radiologic criteria used for the diagnosis of LSS. The precise definitions of all criteria, normal or abnormal values (if applicable), and intra- and interrater reliability were noted by two independent readers. Descriptive statistics were used., Results: A total of 14 semiquantitative or qualitative radiologic parameters were identified and distinguished according to relevant anatomic spaces into criteria for central canal stenosis, lateral (recess) stenosis, and foraminal stenosis. Great variability in terms of the exact definitions of the criteria was found. For 10 of the 14 criteria, the intra- and interrater reliability data were found with kappa values ranging from 0.01 to 1.0., Conclusion: Our systematic literature review identified 14 different semiquantitative or qualitative radiologic criteria that are used for the diagnosis of LSS; however, these criteria show remarkable variability in terms of their exact individual definitions and intra- and interrater reliability.

Lumbar Spinal Stenosis is a typical disease of the elderly patient that mainly originates in degenerative multisegmental changes of the lumbar vertebral column. The classical symptom of pain irradiation into the legs whilst walking and relief with standing is similar to peripheral arterial disease presentation but differs in the sense that symptoms can be triggered through lumbar extension and relieved with lumbar flexion whereas arterial disease is correlated with pathological arteriovascular findings. Diagnosis is usually confirmed through magnetic resonance imaging (MRI) and response to conservative treatment (analgetics, physiotherapy, epidural injections) is usually good in the majority of cases. Only a minority of about 20% of all cases show progressive disease and may necessitate surgical interventions.

Purpose: To develop a list of radiologic criteria for describing lumbar spinal stenosis, to learn from experts which parameters they consider to be most important, and to assess the strength of agreement among experts on the most relevant criteria., Materials and Methods: An expert panel of 41 radiologists (musculoskeletal experts and neuroradiologists from Europe and the United States) was formed. A three-round Delphi survey was conducted. Twenty-seven of the 41 nominated experts agreed to participate; 21 completed all three rounds. In the first round, experts were asked to complete a list of suggested parameters and cutoff values to describe lumbar spinal stenosis. In the second round, panelists rated the diagnostic relevance of each parameter (visual analog scale, 0-10). In the third round, panelists were provided with the group results (median and range) and their own answers and had the opportunity to adapt their judgments from round 2. To assess the degree of consensus among experts, the Cronbach α was calculated., Results: The qualitative criteria disk protrusion and perineural intraforaminal fat were rated as the most important diagnostic indicators, with median scores of 9 (range, 2-10). The highest rated quantitative criterion was the anteroposterior diameter of the osseous canal, with a median score of 8; however, there was a wide range of scores (range, 0-10). The median Cronbach α of all panelists within the group was 0.81 after the third round., Conclusion: Results of the survey suggest that there are no broadly accepted quantitative criteria and only partially accepted qualitative criteria for the diagnosis of lumbar spinal stenosis. The latter include disk protrusion, lack of perineural intraforaminal fat, hypertrophic facet joint degeneration, absent fluid around the cauda equine, and hypertrophy of the ligamentum flavum., (© RSNA, 2012.)

Background: Beside symptoms and clinical signs radiological findings are crucial in the diagnosis of lumbar spinal stenosis (LSS). We investigate which quantitative radiological signs are described in the literature and which radiological criteria are used to establish inclusion criteria in clinical studies evaluating different treatments in patients with lumbar spinal stenosis., Methods: A literature search was performed in Medline, Embase and the Cochrane library to identify papers reporting on radiological criteria to describe LSS and systematic reviews investigating the effects of different treatment modalities., Results: 25 studies reporting on radiological signs of LSS and four systematic reviews related to the evaluation of different treatments were found. Ten different parameters were identified to quantify lumbar spinal stenosis. Most often reported measures for central stenosis were antero-posterior diameter (< 10 mm) and cross-sectional area (< 70 mm(2)) of spinal canal. For lateral stenosis height and depth of the lateral recess, and for foraminal stenosis the foraminal diameter were typically used. Only four of 63 primary studies included in the systematic reviews reported on quantitative measures for defining inclusion criteria of patients in prognostic studies., Conclusions: There is a need for consensus on well-defined, unambiguous radiological criteria to define lumbar spinal stenosis in order to improve diagnostic accuracy and to formulate reliable inclusion criteria for clinical studies.

Background: Lumbar spinal stenosis is the most frequent reason for spinal surgery in elderly people. For patients with moderate or severe symptoms different conservative and surgical treatment modalities are recommended, but knowledge about the effectiveness, in particular of the conservative treatments, is scarce. There is some evidence that surgery improves outcome in about two thirds of the patients. The aims of this study are to derive and validate a prognostic prediction aid to estimate the probability of clinically relevant improvement after surgery and to gain more knowledge about the future course of patients treated by conservative treatment modalities., Methods/design: This is a prospective, multi-centre cohort study within four hospitals of Zurich, Switzerland. We will enroll patients with neurogenic claudication and lumbar spinal stenosis verified by Computer Tomography or Magnetic Resonance Imaging. Participating in the study will have no influence on treatment modality. Clinical data, including relevant prognostic data, will be collected at baseline and the Swiss Spinal Stenosis Questionnaire will be used to quantify severity of symptoms, physical function characteristics, and patient's satisfaction after treatment (primary outcome). Data on outcome will be collected 6 weeks, and 6, 12, 24 and 36 months after inclusion in the study. Applying multivariable statistical methods, a prediction rule to estimate the course after surgery will be derived., Discussion: The ultimate goal of the study is to facilitate optimal, knowledge based and individualized treatment recommendations for patients with symptomatic lumbar spinal stenosis.