Search

Purpose: To determine whether there was an association between self-reported preoperative exercise and postoperative outcomes after lumbar fusion spinal surgery. Method: We performed a retrospective multivariable analysis of the prospective Canadian Spine Outcomes and Research Network (CSORN) database of 2,203 patients who had elective single-level lumbar fusion spinal surgeries. We compared adverse events and hospital length of stay between patients who reported regular exercise (twice or more per week) prior to surgery (“Regular Exercise”) to those exercising infrequently (once or less per week) (“Infrequent Exercise”) or those who did no exercise (“No Exercise”). For all final analyses, we compared the Regular Exercise group to the combined Infrequent Exercise or No Exercise group. Results: After making adjustments for known confounding factors, we demonstrated that patients in the Regular Exercise group had fewer adverse events (adjusted odds ratio 0.72; 95% CI: 0.57, 0.91; p = 0.006) and significantly shorter lengths of stay (adjusted mean 2.2 vs. 2.5 d, p = 0.029) than the combined Infrequent Exercise or No Exercise group. Conclusions: Patients who exercised regularly twice or more per week prior to surgery had fewer postoperative adverse events and significantly shorter hospital lengths of stay compared to patients that exercised infrequently or did no exercise. Further study is required to determine effectiveness of a targeted prehabilitation programme.

Depression is higher among spine patients than among the general population. Some small studies, but not others, have suggested that depression may be a predictor of worse outcome after surgery.Determination whether there is an association between depression and worse response to surgery among spine patients.The national, prospective, Canadian Spine Outcome Research Network (CSORN) surgical outcome registry.All patients in the CSORN registry who received surgery for thoracic or lumbar degenerative deformity, stenosis, spondylolisthesis, disc disease, or disc herniation with a minimum of 12 months follow-up postoperation (n = 2310).Oswestry Disability Index (ODI), SF12 Physical Component Score (PCS), European Quality of Life (EuroQoL), and pain scales.Change in preoperative to 12-month postoperative ODI, and secondary measures, were compared to assess if there was an association between preoperative depression, as measured by PHQ9, and smaller response to surgery. Multivariate regression analysis was used to search for preoperative factors which might interact with PHQ9 to predict ODI outcome.Patients with PHQ95, associated with minimal to no depression, had the smallest ODI improvement (-16.8 [95%CI -18.1 to -15.3]) and patients with severe preoperative depression (PHQ9 ≥ 10) had the largest ODI improvement (-22.8 [95%CI -24.1 to -21.5]; p.00001). Similar findings were found in the EQ5D and PCS. Pain improvement was not different between depression levels. Multivariate modeling found worse baseline PHQ9 and ODI, greater age, nicotine use, more operative levels, and worse American Society of Anesthesiology score was predictive of worse ODI outcomes.Depressed patients have similar or better relative improvements in disability, quality of life, and pain, when compared to nondepressed patients, although their preoperative and postoperative levels of disability are higher. Surgeons should not be concerned that depression will reduce the patient-reported beneficial response to surgical intervention.

Patient satisfaction is an important indicator used to monitor quality of care and outcomes after spine surgery.To examine the complex relationship between preoperative expectations, fulfillment of expectations, postsurgical outcomes, and satisfaction after spine surgery.In this national study of patients undergoing elective surgery for degenerative spinal conditions from the Canadian Spine Outcomes and Research Network Registry, we used logistic regression to examine the relationships between patient satisfaction with surgery (1-5 scale), preoperative expectation score (0 = none to 100 = highest), fulfillment of expectations, and disability and pain improvement.Fifty-eight percent of patients were extremely satisfied, and 3% were extremely dissatisfied. Expectations were variable and generally high (mean 79.5 of 100) while 17.3% reported that none of their expectations were met, 49.8% reported that their most important expectation was met, and 32.9% reported that their most important expectation was not met but others were. The results from the fully adjusted ordinal logistic model for satisfaction indicate that satisfaction was higher among patients with higher preoperative expectations (odds ratio [OR] [95% CI]: 1.11, [1.04-1.19]), reporting important improvements in disability (OR [95% CI]: 2.52 [1.96-3.25]) and pain (OR [95% CI]: 1.64 [1.25-2.15]) and reporting that expectations were fulfilled (OR = 80.15, for all expectations were met). The results were similar for lumbar and cervical patients.Given the dominant impact of expectation fulfillment on satisfaction level, there is an opportunity for improving overall patient satisfaction by specifically assessing and mitigating the potential discrepancies between patients' preoperative expectations and likely surgical outcomes. The findings are likely relevant across elective surgical populations.

STUDY DESIGN Prospective cohort study. OBJECTIVE Among patients with cervical spondylotic myelopathy (CSM), we aimed to evaluate the extent to which: (1) pre-operative cervical sagittal alignment is associated with health-related quality of life, function, and symptoms; (2) surgery leads to changes in cervical sagittal alignment; and (3) post-operative cervical sagittal alignment is associated with health-related quality of life, function, and symptoms at 12 months of follow-up. SUMMARY OF BACKGROUND DATA The importance of maintaining or improving cervical sagittal alignment in the surgical management of patients with CSM has not been established. METHODS We measured C2-C7 cobb angle, T1 slope, and C2-C7 cervical sagittal vertical axis (cSVA). We tested for associations with Neck Disability Index, Pain Scales for neck and arm pain, EuroQol 5D, Short Form 12 (SF-12) Physical and Mental Component Summaries (PCS and MCS), and modified Japanese Orthopaedic Association scores. We adjusted for potential confounders using multiple linear regression, and we performed various pre-specified subgroup (cSVA >40 mm, surgical approach) and sensitivity analyses. RESULTS Among 250 patients, adjusted analyses yielded significant inverse associations prior to surgery between each of cSVA and T1 slope with SF12 PCS (T1 slope: -0.14, 95% CI -0.26 to -0.01, p = 0.03; C2-C7 cSVA: -0.13, 95% CI -0.21 to -0.05 p

OBJECTIVE Many studies have utilized a combined cohort of patients with degenerative spondylolisthesis (DS) and isthmic spondylolisthesis (IS) to evaluate indications and outcomes. Intuitively, these are very different populations, and rates, indications, and outcomes may differ. The goal of this study was to compare specific patient characteristics associated with the utilization of a posterior lumbar interbody device between cohorts of patients with DS and IS, as well as to compare rates of interbody device use and patient-rated outcomes at 1 year after surgical treatment. METHODS The authors included patients who underwent posterior lumbar interbody fusion or instrumented posterolateral fusion for grade I or II DS or IS and had been enrolled in the Canadian Spine Outcomes and Research Network registry from 2009 to 2016. The outcome measures were score on the Oswestry Disability Index, scores for back pain and leg pain on the numeric rating scale, and mental component summary (MCS) score and physical component summary score on the 12-Item Short-Form Health Survey. Descriptive statistics were used to compare spondylolisthesis groups, logistic regression was used to compare interbody device use, and the chi-square test was used to compare the proportions of patients who achieved a minimal clinically important difference (MCID) at 1 year after surgery. RESULTS In total, 119 patients had IS and 339 had DS. Patients with DS were more commonly women, older, less likely to smoke, and more likely to have neurogenic claudication and comorbidities, whereas patients with IS more commonly had radicular pain, neurological deficits, and worse back pain. Spondylolisthesis was more common at the L4–5 level in patients with DS and at the L5–S1 level in patients with IS. Similar proportions of patients had an interbody device (78.6% of patients with DS vs 82.4% of patients with IS, p = 0.429). Among patients with IS, factors associated with interbody device utilization were BMI ≥ 30 kg/m2 and increased baseline leg pain intensity. Factors associated with interbody device utilization in patients with DS were younger age, increased number of total comorbidities, and lower baseline MCS score. For each outcome measure, similar proportions of patients in the surgical treatment and spondylolisthesis groups achieved the MCID at 1 year after surgery. CONCLUSIONS Although the demographic and patient characteristics associated with interbody device utilization differed between cohorts, similar proportions of patients attained clinically meaningful improvement at 1 year after surgery.

OBJECTIVE Time to return to work (RTW) after elective lumbar spine surgery is variable and dependent on many factors including patient, work-related, and surgical factors. The primary objective of this study was to describe the time and rate of RTW after elective lumbar spine surgery. Secondary objectives were to determine predictors of early RTW (< 90 days) and no RTW in this population. METHODS A retrospective analysis of prospectively collected data from the multicenter Canadian Spine Outcomes and Research Network (CSORN) surgical registry was performed to identify patients who were employed and underwent elective 1- or 2-level discectomy, laminectomy, and/or fusion procedures between January 2015 and December 2019. The percentage of patients who returned to work and the time to RTW postoperatively were calculated. Predictors of early RTW and not returning to work were determined using a multivariable Cox regression model and a multivariable logistic regression model, respectively. RESULTS Of the 1805 employed patients included in this analysis, 71% returned to work at a median of 61 days. The median RTW after a discectomy, laminectomy, or fusion procedure was 51, 46, and 90 days, respectively. Predictors of early RTW included male gender, higher education level (high school or above), higher preoperative Physical Component Summary score, working preoperatively, a nonfusion procedure, and surgery in a western Canadian province (p < 0.05). Patients who were working preoperatively were twice as likely to RTW within 90 days (HR 1.984, 95% CI 1.680–2.344, p < 0.001) than those who were employed but not working. Predictors of not returning to work included symptoms lasting more than 2 years, an increased number of comorbidities, an education level below high school, and an active workers’ compensation claim (p < 0.05). There were fourfold odds of not returning to work for patients who had not been working preoperatively (OR 4.076, 95% CI 3.087–5.383, p < 0.001). CONCLUSIONS In the Canadian population, 71% of a preoperatively employed segment returned to work after 1- or 2-level lumbar spine surgery. Most patients who undergo a nonfusion procedure RTW after 6 to 8 weeks, whereas patients undergoing a fusion procedure RTW at 12 weeks. Working preoperatively significantly increased the likelihood of early RTW.

BACKGROUND CONTEXT Spine patients have a higher rate of depression then the general population which may be caused in part by levels of pain and disability from their spinal disease. PURPOSE Determination whether improvements in health-related quality of life (HRQOL) resulting from successful spine surgery leads to improvements in mental health. STUDY DESIGN/SETTING The Canadian Spine Outcome Research Network prospective surgical outcome registry. OUTCOME MEASURES Change between preoperative and postoperative SF12 Mental Component Score (MCS). Secondary outcomes include European Quality of Life (EuroQoL) Healthstate, SF-12 Physical Component Score (PCS), Oswestry Disability Index (ODI), Patient Health Questionaire-9 (PHQ9), and pain scales. METHODS The Canadian Spine Outcome Research Network registry was queried for all patients receiving surgery for degenerative thoracolumbar spine disease. Exclusion criteria were trauma, tumor, infection, and previous spine surgery. SF12 Mental Component Scores (MCS) were compared between those with and without significant improvement in postoperative disability (ODI) and secondary measures. Multivariate analysis examined factors predictive of MCS improvement. RESULTS Eighteen hospitals contributed 3222 eligible patients. Worse ODI, EuroQoL, PCS, back pain and leg pain correlated with worse MCS at all time points. Overall, patients had an improvement in MCS that occurred within 3 months of surgery and was still present 24 months after surgery. Patients exceeding Minimally Clinically Important Differences in ODI had the greatest improvements in MCS. Major depression prevalence decreased up to 48% following surgery, depending on spine diagnosis. CONCLUSIONS Large scale, real world, registry data suggests that successful surgery for degenerative lumbar disease is associated with reduction in the prevalence of major depression regardless of the specific underlaying diagnosis. Worse baseline MCS was associated with worse baseline HRQOL and improved postoperatively with coincident improvement in disability, emphasizing that mental wellness is not a static state but may improve with well-planned spine surgery.

Controversy exists regarding the optimal surgical treatment of degenerative lumbar spondylolisthesis (DS). Not all DS patients are the same, and the degree to which inherent stability may dictate treatment is unknown. The purpose of this study was to determine the variability in surgical approach relative to surgeon classified stability. The secondary objective was to compare patient-reported outcomes (PROs) across different surgical techniques and grades of stability. Patients prospectively enrolled from eleven tertiary care institutions and followed from 2015 to 2019. The surgical technique was at the surgeon’s discretion. Surgeons were asked to grade the degree of instability based on the degenerative spondylolisthesis instability classification system (DSIC). DSIC categorizes three different types (I-stable, II-potentially unstable, and III-unstable). One-year changes in PROs were compared between each group. Multivariable regression was used to identify any characteristics that explained variability in treatment. There were 323 patients enrolled in this study. Surgeons’ stability classification versus procedure [decompression alone (D)/decompression and posterolateral fusion (D-PL)/and decompression with posterior/transforaminal lumbar interbody fusion (D-PLIF/TLIF)] were as follows: type I (n = 91): D-41%/D-PL-13%/D-PLIF/TLIF-46%; type II (n = 175): D-23%/D-PL-17%/D-PLIF/TLIF-60%; and type III (n = 57):(D-0%/D-PL-14%/D-PLIF/TLIF-86%). Type I patients undergoing D-PL had some improvements in EQ-5D and NRS versus those undergoing D-PLIF/TLIF but otherwise there were no other significant differences between groups. Regression analysis demonstrated advanced age (OR = 1.06, CI 1.02–10.12) and type I (OR = 2.61, CI 1.17–5.81) were associated with receiving decompression surgery alone. There exists considerable variation in surgical management of DS in Canada. Given similar PROs in two of the three groups, there is potential to tailor surgical intervention and improve resource utilization.

OBJECTIVE Patients undergoing spine surgery generally have high expectations for improvement postoperatively. Little is known about how these expectations are affected by the diagnosis. The purpose of this study was to examine whether preoperative expectations differ based on diagnostic pathoanatomical patterns in elective spine surgery patients. METHODS Patients with common degenerative cervical/lumbar pathology (lumbar/cervical stenosis, lumbar spondylolisthesis, and cervical/lumbar disc herniation) who had given their consent for surgery were analyzed using the Canadian Spine Outcomes and Research Network (CSORN). Patients reported the changes they expected to experience postoperatively in relation to 7 separate items using a modified version of the North American Spine Society spine questionnaire. Patients were also asked about the most important item that would make them consider the surgery a success. Sociodemographic, lifestyle, and clinical variables were also collected. RESULTS There were 3868 eligible patients identified within the network for analysis. Patients with lumbar disc herniation had higher expectations for relief of leg pain compared with stenosis and lumbar degenerative spondylolisthesis cohorts within the univariate analysis. Cervical stenosis (myelopathy) patients were more likely to rank general physical capacity as their most important expectation from spine surgery. The multinomial regression analysis showed that cervical myelopathy patients have lower expectations for relief of arm or neck pain from surgery (OR 0.54, 0.34–0.88; p < 0.05). Patient factors, including age, symptoms (pain, disability, depression), work status, and lifestyle factors, were significantly associated with expectation, whereas the diagnoses were not. CONCLUSIONS Patients with degenerative spinal conditions consenting for spine surgery have high expectations for improvement in all realms of their daily lives. With the exception of patients with cervical myelopathy, patient symptoms rather than diagnoses had a more substantial impact on the dimensions in which patients expected to improve or their most important expected change. Determination of patient expectation should be individualized and not biased by pathoanatomical diagnosis.

While symptomatic degenerative and isthmic spondylolisthesis cause pain and surgical management improves quality of life, it is less clear which surgical strategies are most helpful. In this review, we seek to outline the accuracy and reliability of classification schemes and suggest how machine-learning tools can potentially help identify optimal surgical strategies for individual patients. In addition, we examine the role of new surgical strategies in degenerative and isthmic spondylolisthesis, namely using lateral and oblique interbody fusions. Herein we discuss lateral and oblique interbody fusions in spondylolisthesis within a framework of accepted surgical goals, sagittal plane balance considerations, and cost-effectiveness.

Background: Symptomatic lumbar spinal stenosis (SLSS) is a condition in which narrowing of the spinal canal results in entrapment and compression of neurovascular structures. Decompressive surgery, with or without spinal fusion, is recommended for those with severe symptoms for whom conservative management has failed. However, significant persistent pain, functional limitations, and narcotic use can affect up to one third of patients postsurgery. Aims: The aim of this study will be to identify predictors of outcomes 1-year post SLSS surgery with a focus on modifiable predictors. Methods: The Canadian Spine Outcomes Research Network (CSORN) is a large database of prospectively collected data on pre- and postsurgical outcomes among surgical patients. We include participants with a primary diagnosis of SLSS undergoing their first spine surgery. Outcomes are measured at 12 months after surgery and include back and leg pain, disability (Oswestry Disability Index, ODI), walking capacity (ODI item 4), health-related quality of life, and an overall recovery composite outcome (clinically important changes in pain, disability, and quality of life). Predictors include demographics (education level, work status, marital status, age, sex, body mass index), physical activity level, smoking status, previous conservative treatments, medication intake, depression, patient expectations, and other comorbidities. A multivariate partial least squares model is used to identify predictors of outcomes. Conclusion: Study results will inform targeted SLSS interventions, either for the selection of best candidates for surgery or the identification of targets for presurgical rehabilitation programs.

BACKGROUND Perioperative adverse events (AEs) lead to patient disappointment and greater costs. There is a paucity of data on how AEs affect long-term outcomes. OBJECTIVE To examine perioperative AEs and their impact on outcome after lumbar spine surgery. METHODS A total of 3556 consecutive patients undergoing surgery for lumbar degenerative disorders enrolled in the Canadian Spine Outcomes and Research Network were analyzed. AEs were defined using the validated Spine AdVerse Events Severity system. Outcomes at 3, 12, and 24 mo postoperatively included the Owestry Disability Index (ODI), 12-Item Short-Form Health Survey (SF-12) Physical (PCS) and Mental (MCS) Component Summary scales, visual analog scale (VAS) leg and back, EuroQol-5D (EQ5D), and satisfaction. RESULTS AEs occurred in 767 (21.6%) patients, and 85 (2.4%) patients suffered major AEs. Patients with major AEs had worse ODI scores and did not reach minimum clinically important differences at 2 yr (no AE: 25.7 ± 19.2, major: 36.4 ± 19.1, P

OBJECTIVERecently identified prognostic variables among patients undergoing surgery for cervical spondylotic myelopathy (CSM) are limited to two large international data sets. To optimally inform shared clinical decision-making, the authors evaluated which preoperative clinical factors are significantly associated with improvement on the modified Japanese Orthopaedic Association (mJOA) scale by at least the minimum clinically important difference (MCID) 12 months after surgery, among patients from the Canadian Spine Outcomes and Research Network (CSORN).METHODSThe authors performed an observational cohort study with data that were prospectively collected from CSM patients at 7 centers between 2015 and 2017. Candidate variables were tested using univariable and multiple binomial logistic regression, and multiple sensitivity analyses were performed to test assumptions about the nature of the statistical models. Validated mJOA MCIDs were implemented that varied according to baseline CSM severity.RESULTSAmong 205 patients with CSM, there were 64 (31%) classified as mild, 86 (42%) as moderate, and 55 (27%) as severe. Overall, 52% of patients achieved MCID and the mean change in mJOA score at 12 months after surgery was 1.7 ± 2.6 points (p < 0.01), but the subgroup of patients with mild CSM did not significantly improve (mean change 0.1 ± 1.9 points, p = 0.8). Univariate analyses failed to identify significant associations between achieving MCID and sex, BMI, living status, education, smoking, disability claims, or number of comorbidities. After adjustment for potential confounders, the odds of achieving MCID were significantly reduced with older age (OR 0.7 per decade, 95% CI 0.5–0.9, p < 0.01) and higher baseline mJOA score (OR 0.8 per point, 95% CI 0.7–0.9, p < 0.01). The effects of symptom duration (OR 1.0 per additional month, 95% CI 0.9–1.0, p = 0.2) and smoking (OR 0.4, 95% CI 0.2–1.0, p = 0.06) were not statistically significant.CONCLUSIONSSurgery is effective at halting the progression of functional decline with CSM, and approximately half of all patients achieve the MCID. Data from the CSORN confirmed that older age is independently associated with poorer outcomes, but novel findings include that patients with milder CSM did not experience meaningful improvement, and that symptom duration and smoking were not important. These findings support a nuanced approach to shared decision-making that acknowledges some prognostic uncertainty when weighing the various risks, benefits, and alternatives to surgical treatment.

Study design A multicenter ambispective study using the Canadian Spine Outcomes and Research Network to compare clinical outcomes in adult patients with isthmic spondylolisthesis who received surgery. Objective The purpose of this study is to compare 1-year postoperative clinical outcomes between posterior instrumented fusion with and without interbody fusion in patients with isthmic spondylolisthesis. Summary of background data Despite the increased use of interbody fusion in patients with isthmic spondylolisthesis, clinical superiority has not been demonstrated. It remains unclear what the optimal surgical approach is for this population. Materials and methods The primary outcome was changed in leg pain at 1 year. Secondary outcomes were changed in Oswestry Disability Index, Short Form-12 Physical Component Score, and back pain at 1-year postoperative follow-up, estimated intraoperative blood loss, length of surgery, length of stay, number of transfusions, and adverse events. Descriptive statistics, Student t test, χ2 test, and stepwise multivariable regression were used for analysis. Results In total, 300 patients were included in this study. Of the 300 patients, 252 received posterolateral instrumented fusion with interbody fusion and 48 received posterolateral instrumented fusion alone. There were no significant differences in primary and secondary clinical outcomes at 1-year postoperative follow-up between the 2 groups. There were no significant differences in estimated blood loss (441 vs. 356 mL), length of surgery (210 vs. 224 min), length of stay (4 vs. 4 d), rate of transfusions (5.6% vs. 8.3%), and number of adverse events (33% vs. 23%) between patients who received interbody fusion and patients who did not. The addition of interbody fusion was not a significant variable for primary and secondary clinical outcomes in the stepwise multivariable regression analysis. Conclusions There were no significant differences in clinical outcomes at 1 year or in the number of early complications between patients who received posterolateral fusion or posterior/transformational lumbar interbody fusion. Level of evidence Level III.

BACKGROUND Understanding patient expectations is a critical component of patient-centered care; however, little is known about which expectation(s) are most important to patients as they relate to their sense of post-operative success. PURPOSE To investigate patient's preoperative expectations of change in symptoms, function and well-being resulting from surgical intervention and to examine the associations between socio-demographic, lifestyle, health status and clinical characteristics with patient outcome expectations. STUDY DESIGN Observational cross-sectional study. SAMPLE Pre-operative data from the Canadian Spine Outcomes and Research Network national registry of patients of patients (n=4333) undergoing surgery for degenerative spinal conditions between 2012 and 2017. OUTCOME MEASURES Patients reported their expectations as a result of the surgery (0 (no change), 1 (somewhat better), 2 (better) or 3 (much better)) for seven items: leg/arm pain, back/neck pain, independence in everyday activities, sporting activities/recreation, general physical capacity, frequency and quality of social contacts and mental well-being. Patients also reported the single most important change expected. METHODS Data on demographic, lifestyles, health status, clinical factors and reasons for having surgery were also collected. Factor analysis was used to examine the multidimensionality of expectations. Multivariate linear regression was used to examine factors associated with expectations. RESULTS Over 80% of patients reported expectation for improvements (at least somewhat better) in all items with the exception of social contacts (75.8%). Expectations are multidimensional; a two factor structure emerged indicating two expectation dimensions (pain relief and overall functional well-being). Two expectation scores were calculated corresponding to the two dimensions (0-100), with higher scores reflecting higher expectations. The mean ± standard deviation pain relief expectation score was 78.5 ± 24.7 and the mean overall functional well-being expectation score was 69.7 ± 24.4. In multivariate analysis, the variables associated with these dimensions either differed or differed in degree of influence. For example, higher pain and disability scores, thoraco-lumbar location and diagnosis of spondylolisthesis were associated with higher expectations in both dimensions, while longer disease duration was only associated with lower overall functional well-being expectations. The top three most important expected change items were pain (improvement of leg or arm pain (29.1%) / improvement in back/neck pain (26.0%)), improvement in general capacity/function (21.0%), and improvement of independence in everyday activities (15.9%). Rankings of the most important expected change were similar across socio-demographic, lifestyle, health status and clinical variables examined. CONCLUSIONS Our findings highlight the need to identify and address specific individual expectations as part of the shared decision-making and pre-surgery education process.

OBJECTIVE Degenerative cervical myelopathy (DCM) is an important public health issue. Surgery is the mainstay of treatment for moderate and severe DCM. Delayed discharge of patients after DCM surgery is associated with increased healthcare costs. There is a paucity of data regarding predictive factors for discharge destination after scheduled surgery for patients with DCM. The purpose of this study was to identify factors predictive of home versus nonhome discharge after DCM surgery. METHODS Patients undergoing scheduled DCM surgery who had been enrolled in a prospective DCM substudy of the Canadian Spine Outcomes and Research Network registry between January 2015 and October 2020 were included in this retrospective analysis. Patient data were evaluated to identify potential factors predictive of home discharge after surgery. Logistic regression was used to identify independent factors predictive of home discharge. A multivariable model was then used as a final model. RESULTS Overall, 639 patients were included in the initial analysis, 543 (85%) of whom were discharged home. The mean age of the entire cohort was 60 years (SD 11.8 years), with a BMI of 28.9 (SD 5.7). Overall, 61.7% of the patients were female. The mean length of stay was 2.72 days (SD 1.7 days). The final internally validated bootstrapped multivariable model revealed that younger age, higher 9-Item Patient Health Questionnaire score, lower Neck Disability Index scores, fewer operated levels, mJOA scores indicating mild disease, anterior cervical discectomy and fusion procedure, and no perioperative adverse effects were predictive of home discharge. CONCLUSIONS Younger age, less neck-related disability, fewer operated levels, more significant depression, less severe myelopathy, anterior cervical discectomy and fusion procedure, and no perioperative adverse effects are predictive of home discharge after surgery for DCM. These factors can help to guide clinical decision-making and optimize postoperative care pathways.

Study Design Ambispective cohort study. Objective Canada has a government-funded universal health care system. The United States utilizes a multitier public and private system. The objective is to investigate differences in clinical outcomes between those surgically treated for lumbar disc herniation in a universal health care and multitier health system. Methods Surgical lumbar disc herniation patients enrolled in the Canadian Spine Outcome Research Network (CSORN) were compared with the surgical cohort enrolled in the Spine Patients Outcome Research Trial (SPORT) study. Baseline demographics and spine-related patient-reported outcomes (PROs) were compared at 3 months and 1 year post-operatively. Results The CSORN cohort consisted of 443 patients; the SPORT cohort had 763 patients. Patients in the CSORN cohort were older (46.4 ± 13.5 vs 41.0 ± 10.8, P < .001) and were more likely to be employed (69.5% vs 60.3%, P = .003). The CSORN cohort demonstrated significantly greater rates of satisfaction after surgery at 3 months (87.2% vs 64.8%, P < .0001) and 1 year (85.6% vs 69.6%, P < .0001). Improvements in back and leg pain followed similar trajectories in the two cohorts, but there was less improvement on ODI in the CSORN cohort ( P < .01). On multivariable logistic regression, the CSORN cohort was a significant independent predictor of patient satisfaction at 1-year follow-up ( P < .001). Conclusions Despite less improvement on ODI, patients enrolled in CSORN, as part of a universal health care system, reported higher rates of satisfaction at 3 months and 1 year post-operatively compared to patients enrolled within a multitier health system.

OBJECTIVE Treatment of degenerative lumbar diseases has been shown to be clinically effective with open transforaminal lumbar interbody fusion (O-TLIF) or minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). Despite this, a substantial proportion of patients do not meet minimal clinically important differences (MCIDs) in patient-reported outcomes (PROs). The objectives of this study were to compare the proportions of patients who did not meet MCIDs after O-TLIF and MIS-TLIF and to determine potential clinical factors associated with failure to achieve MCID. METHODS The authors performed a retrospective analysis of consecutive patients who underwent O-TLIF or MIS-TLIF for lumbar degenerative disorders and had been prospectively enrolled in the Canadian Spine Outcomes and Research Network. The authors analyzed the Oswestry Disability Index (ODI) scores, physical and mental component summary scores of SF-12, numeric rating scale (NRS) scores for leg and back pain, and EQ-5D scores of the patients in each group who did not meet the MCID of ODI at 2 years postoperatively. RESULTS In this study, 38.8% (137 of 353) of patients in the O-TLIF cohort and 41.8% (51 of 122) of patients in the MIS-TLIF cohort did not meet the MCID of ODI at 2 years postoperatively (p = 0.59). Demographic variables and baseline PROs were similar between groups. There were improvements across the PROs of both groups through 2 years, and there were no differences in any PROs between the O-TLIF and MIS-TLIF cohorts. Multivariable logistic regression analysis demonstrated that higher baseline leg pain score (p = 0.017) and a diagnosis of spondylolisthesis (p = 0.0053) or degenerative disc disease (p = 0.022) were associated with achieving the MCID at 2 years after O-TLIF, whereas higher baseline leg pain score was associated with reaching the MCID after MIS-TLIF (p = 0.038). CONCLUSIONS Similar proportions of patients failed to reach the MCID of ODI at 2 years after O-TLIF or MIS-TLIF. Higher baseline leg pain score was predictive of achieving the MCID in both cohorts, whereas a diagnosis of spondylolisthesis or degenerative disc disease was predictive of reaching the MCID after O-TLIF. These data provide novel insights for patient counseling and suggest that either MIS-TLIF or O-TLIF does not overcome specific patient factors to mitigate clinical success or failure in terms of the intermediate-term PROs associated with 1- to 2-level lumbar fusion surgical procedures for degenerative pathologies.

Cohort study.Our goal was to verify the validity of the global alignment and proportion (GAP) score, SRS-Schwab, and Roussouly theoretical apex of lordosis in predicting mechanical complications in adult spinal deformity (ASD).Achieving adequate sagittal alignment is critical to obtain favorable outcomes in ASD surgery. It has been proposed that mechanical complications are largely secondary to postoperative spinal alignment.Retrospective review of consecutive primary ASD cases that underwent deformity correction in the same institution over a 5-year period. Association between the 6-week postoperative spinal alignment classification and occurrence of mechanical complications on the last follow-up was assessed using logistic regressions. The discriminant capacity was assessed using the receiver operating characteristic (ROC) curve analysis.58.3% (N = 49/84) of patients presented with mechanical complications and 32.1% (N = 27/84) underwent revision surgery. GAP score did not show discriminant ability to predict complications (AUC = 0.53, 95% confidence interval [CI] = 0.40-0.66, P = 0.58). Conversely, the SRS-Schwab sagittal modifier score demonstrated a statistically significant (although modest) predictive value for mechanical complications (AUC = 0.67, 95% CI = 0.54-0.79, P = 0.008). There was a significant association between pelvic tilt (PT) (P = 0.03) and sagittal vertical axis (SVA) (P = 0.01) at 6 weeks postoperatively and the occurrence of later mechanical complications. There was no significant association between matched Roussouly theoretical apex of lordosis and final outcome (P = 0.47).The results point to the complexity of mechanical failure and the high likelihood that causative factors are multifactorial and not limited to alignment measures. GAP score should be used with caution as it may not explain or predict mechanical failure based on alignment in all populations as originally expected. Future studies should focus on etiology, surgical technique, and patient factors in order to generate a more universal score that can be applied to all populations.Level of Evidence: 4.

BACKGROUND CONTEXT The Oswestry Disability Index (ODI) is the most commonly used outcome measure of functional outcome in spine surgery. The ability of the ODI to differentiate pain related functional limitation specifically related to degenerative lumbar spinal stenosis (LSS) is unclear. PURPOSE The purpose of this study was to determine the ability of the functional subsections of the ODI to differentiate the specific patient limitation(s) from symptomatic LSS and the functional impact of surgery. STUDY DESIGN Analysis of prospectively collected data from the Canadian Spine Outcomes and Research Network (CSORN). PATIENT SAMPLE A total of 1,497 lumbar spinal stenosis patients with a dominant complaint of neurogenic claudication, radiculopathy or back pain were identified in the CSORN registry. OUTCOME MEASURES The ODI questionnaire version 2.0 was assessed as an outcome measure. METHODS The difference at baseline and the pre-to-post (1-year) surgical change of the ODI individual questions was assessed. Analysis of variance, two-tailed paired sample Student t test were used for statistical analysis. Cohen d was used as an index of effect size, defined as "large" when d ≥0.8. RESULTS The mean age at surgery was 65 (±11) years and (50.8%) of the patients were female. Preoperatively, highest functional limitations were noted for standing, lifting, walking, pain intensity and social life (mean 3.2, 2.9, 2.5, 2.9, 2.5 respectively). At 1-year follow-up, overall there was a significant improvement in all individual questions and the overall ODI (all p

BACKGROUND Conflicting evidence exists regarding the effectiveness of surgery for degenerative cervical myelopathy (DCM), particularly in mild DCM. OBJECTIVE To prospectively evaluate the impact of surgery on patient-reported outcomes in patients with mild (modified Japanese Orthopaedic Association [mJOA] ≥ 15), moderate (mJOA 12-14), and severe (mJOA

BACKGROUND Degenerative lumbar spinal stenosis is a common condition, predominantly affecting middle-aged and elderly people. This study focused on patients with neurogenic claudication secondary to lumbar stenosis without spondylolisthesis or deformity. PURPOSE To determine whether the addition of fusion to decompression resulted in improved clinical outcomes at 3, 12, and 24 months postsurgery. STUDY DESIGN/SETTING The Canadian Spine Outcomes and Research Network (CSORN) prospective database that includes pre- and postoperative data from tertiary care hospitals. PATIENT SAMPLE The CSORN database was queried for consecutive spine surgery cases of degenerative lumbar stenosis receiving surgical decompression for neurogenic claudication or radiculopathy. Neurogenic claudication patients with baseline and 2-year follow-up data, from four sites, formed the study sample (n=306). The sample was categorized into two groups: (1) those that had decompression alone, and (2) those that underwent decompression plus fusion. OUTCOME MEASURES Change in modified Oswestry Disability Index (ODI), numerical rating scale for back/leg pain, the EuroQol EQ5D, the SF-12 physical, and mental component scores. The primary outcome measure was the ODI at 2 years postoperative. METHODS We conducted a multicenter, ambispective review of consecutive spine surgery patients enrolled between October 2012 and January 2018. RESULTS Baseline characteristics were comparable between groups except for female sex and multilevel pathology (both with greater proportion in the decompression plus fusion group). The decompression plus fusion group had clinically meaningfully more operative time, blood loss, rate of perioperative complication, and length of hospital stay (p Both decompression and decompression plus fusion had a large clinically meaningful impact on generic and disease-specific patient-reported outcome measures within 3 months of surgery which was maintained out to 24-month follow-up. At any follow-up time point, there was no statistical evidence of a difference in these effects favoring decompression plus fusion over decompression alone. CONCLUSIONS The addition of fusion to decompression did not result in improved outcomes at 3-, 12-, or 24-month follow-up. The addition of fusion to decompression provides no advantage to decompression alone for the treatment of patients with neurogenic claudication secondary to lumbar stenosis without spondylolisthesis or deformity.

Some of the chemicals in materials used for packaging food may leak into the food, resulting in human exposure. These include so-called Non-intentionally Added Substances (NIAS), many of them being unidentified and toxicologically uncharacterized. This raises the question of how to address their safety. An approach consisting of identification and toxicologically testing all of them appears neither feasible nor necessary. Instead, it has been proposed to use the threshold of toxicological concern (TTC) Cramer class III to prioritise unknown NIAS on which further safety investigations should focus. Use of the Cramer class III TTC for this purpose would be appropriate if amongst others sufficient evidence were available that the unknown chemicals were not acetylcholinesterase inhibitors or direct DNA-reactive mutagens. While knowledge of the material and analytical chemistry may efficiently address the first concern, the second could not be addressed in this way. An alternative would be use of a bioassay capable of detecting DNA-reactive mutagens at very low levels. No fully satisfactory bioassay was identified. The Ames test appeared the most suitable since it specifically detects DNA-reactive mutagens and the limit of biological detection of highly potent genotoxic carcinogens is low. It is proposed that for a specific migrate, the evidence for absence of mutagenicity based on the Ames test, together with analytical chemistry and information on packaging manufacture could allow application of the Cramer class III TTC to prioritise unknown NIAS. Recommendations, as well as research proposals, have been developed on sample preparation and bioassay improvement with the ultimate aim of improving limits of biological detection of mutagens. Although research is still necessary, the proposed approach should bring significant benefits over the current practices used for safety evaluation of food contact materials.

BACKGROUND CONTEXT Lumbar degenerative stenosis is one of the most common spine pathologies for which surgical intervention is indicated. There is some evidence that a prolonged duration of neurological compression could lead to a failure of surgery to alleviate symptoms. PURPOSE Determination of whether longer symptom duration was associated with worse postoperative disability outcomes after decompressive surgery for lumbar degenerative stenosis. STUDY DESIGN/SETTING The Canadian Spine Outcomes and Research Network (CSORN) prospective database includes pre- and postoperative data from 18 tertiary care hospitals. PATIENT SAMPLE The CSORN database was queried for all cases of degenerative lumbar stenosis receiving surgical decompression for neurogenic claudication or radiculopathy. Patients with tumor, infection, fracture, or previous surgery were excluded. Patients were divided into groups based on symptom duration ( 2 years). OUTCOME MEASURES Change between preoperative and 12-month postoperative Oswestry Disability Index (ODI) was compared between symptom duration groups. Secondary outcomes included SF12 physical component score (PCS), and numeric rating scales for leg and back pain. Outcomes were also assessed at 3 months and 24 months postoperatively. METHODS Change in ODI, and secondary outcome measures, were compared between different symptom duration groups. Multiple regression analysis was used to identify factors interacting with symptom duration to predict change in ODI. RESULTS Four hundred and seventy-eight cases of lumbar stenosis with 12-month postoperative data were identified. Longer symptom duration correlated with less improvement in ODI (p 1 year of symptoms were less likely to achieve a Minimal Clinically Significant Difference in ODI (54.4% vs. 66.1%; p=.03) and were more likely to experience no improvement or worse disability, postoperatively (22.1% vs. 11.3%; p=.008). Similar results were found at 3- and 24-month timepoints. Smaller postoperative improvements in SF12 PCS and leg pain scales were also correlated with longer symptom duration (p CONCLUSIONS Multicenter registry data provides important real-world evidence to guide consent, surgical planning, and health resource management. Longer symptom duration was found to correlate with less improvement in pain and disability after lumbar stenosis surgery suggesting that these patients may benefit from earlier treatment.

OBJECTIVEThere has been a generic dictum in spine and musculoskeletal clinical research that a minimum 2-year follow-up is necessary for patient-reported outcomes (PROs) to adequately assess the therapeutic effect of surgery; however, the rationale for this duration is not evidence based. The purpose of this study was to determine the follow-up time necessary to ensure that the effectiveness of a lumbar surgical intervention is adequately captured for three lumbar pathologies and three common PROs.METHODSUsing the different PROs of pain, physical function, and mental quality of life from the Canadian Spine Outcomes and Research Network (CSORN) prospective database, the authors assessed the time course to the recovery plateau following lumbar spine surgery for lumbar disc herniation, degenerative spondylolisthesis, and spinal stenosis. One-way ANOVA with post hoc testing was used to compare scores on the following standardized PRO measures at baseline and 3, 12, and 24 months postoperatively: Disability Scale (DS), visual analog scale (VAS) for leg and back pain, and SF-12 Mental Component Summary (MCS) and Physical Component Summary (PCS).RESULTSSignificant differences for all spine pathologies and specific PROs were found with one-way ANOVA (p < 0.0001). The time to plateaued recovery after surgery for lumbar disc herniation (661 patients), lumbar stenosis (913 patients), and lumbar spondylolisthesis (563 patients) followed the same course for the following PRO measures: VAS for back and leg pain, 3 months; DS, 12 months; PCS, 12 months; and MCS, 3 months. Beyond these time points, no further significant improvements in PROs were seen. Patients with degenerative spondylolisthesis or spinal stenosis who had undergone fusion surgery plateaued at 12 months on the DS and PCS, compared to 3 months in those who had not undergone fusion.CONCLUSIONSSpecific health dimensions follow distinctly different recovery plateaus, indicating that a 2-year postoperative follow-up is not required for all PROs to accurately assess the treatment effect of lumbar spinal surgery. Ultimately, the clinical research question should dictate the follow-up time and the outcome measure utilized; however, there is now evidence to guide the specific duration of follow-up for pain, physical function, and mental quality of life dimensions.

INTRODUCTION Surgical treatment improves quality of life in patients with adult degenerative scoliosis (ADS). However, open ADS surgeries are complex, large magnitude operations associated with a high rate of complications. The lateral transpsoas interbody fusion technique is a less invasive alternative to open ADS surgery, but less invasive techniques tend to be more expensive. The objective of this study was to evaluate the cost effectiveness of the transpsoas technique for patients with ADS over a 12-month time horizon from a public payer perspective. METHODS A cost-effectiveness analysis was performed based on a consecutive case series of patients who underwent ADS surgeries between 2006 and 2012. Effectiveness was expressed as the difference in patient reported preoperative and 12-month postoperative health-related quality of life (HRQOL), which was measured in quality-adjusted life years. Health-care resource use was tabulated based on a clinical chart review on an item-by-item basis. Unit cost data were obtained from published provincial costs in Alberta, Canada. All costs were adjusted to 2015 Canadian dollars. The base case analysis included costs for the surgery, initial hospitalization, and treatment for complications over a 12-month follow-up period. The uncomplicated case analysis included costs for the surgery and initial hospitalization only. The joint uncertainty surrounding the cost and HRQOL differences was estimated using bootstrapping with 10,000 replicates. RESULTS A total of 10 open technique and 12 transpsoas technique T11–pelvis fusions were included in the analysis. In the base case analysis, the transpsoas technique was less costly compared with the open technique, total cost of $83,513 (95% CI: $72,772–$94,253) versus $111,381 (95% CI: $36,340–$186,423), respectively (incremental cost $27,869), and was associated with 0.06 more quality-adjusted life years and/or patient. However, in the uncomplicated case, the open technique was less costly compared with the transpsoas technique ($47,795 [95% CI: $39,003–$56,586] vs $76,510 [95% CI: $72,273–$80,746]), respectively, with an incremental cost of $28,715. Based on the probabilistic analysis of 10,000 bootstrap iterations for the base case analysis, the transpsoas technique was more effective and less costly compared with the open technique 57% of time. One-way deterministic sensitivity analysis by adjusting bone-morphogenetic protein-2 dosage further improved cost effectiveness of the transpsoas technique by lowering overall costs. CONCLUSIONS Transpsoas surgeries were associated with better outcomes in terms of HRQOL and lower costs over 1-year follow-up period compared with more invasive open technique. This study should be viewed as a pilot evaluation and should be replicated in a larger prospective multicenter controlled study.

Retrospective review of results from a prospectively collected Canadian cohort in comparison to published literature.(1) To investigate whether patients in a universal health care system have different outcomes than those in a multitier health care system in surgical management of degenerative spondylolisthesis (DS). (2) To identify independent factors predictive of outcome in surgical DS patients.Canada has a national health insurance program with unique properties. It is a single-payer system, coverage is universal, and access to specialist care requires referral by the primary care physician. The United States on the other hand is a multitier public/private payer system with more rapid access for insured patients to specialist care.Surgical DS patients treated between 2013 and 2016 in Canada were identified through the Canadian Spine Outcome Research Network (CSORN) database, a national registry that prospectively enrolls consecutive patients with spinal pathology from 16 tertiary care academic hospitals. This population was compared with the surgical DS arm of patients treated in the Spine Patients Outcome Research Trial (SPORT) study. We compared baseline demographics, spine-related, and health-related quality of life (HRQOL) outcomes at 3 months and 1 year. Multivariate analysis was used to identify factors predictive of outcome in surgical DS patients.The CSORN cohort of 213 patients was compared with the SPORT cohort of 248 patients. Patients in the CSORN cohort were younger (mean age 60.1 vs. 65.2; p.001), comprised fewer females (60.1% vs. 67.7%; p=.09), and had a higher proportion of smokers (23.3% vs. 8.9%; p.001). The SPORT cohort had more patients receiving compensation (14.6% vs. 7.7%; p.001). The CSORN cohort consisted of patients with slightly greater baseline disability (Oswestry disability index scores: 47.7 vs. 44.0; p=.008) and had more patients with symptom duration of greater than 6 months (93.7% vs. 62.1%; p.001). The CSORN cohort showed greater satisfaction with surgical results at 3 months (91.1% vs. 66.1% somewhat or very satisfied; p.01) and 1 year (88.2% vs. 71.0%, p.01). Improvements in back and leg pain were similar comparing the two cohorts. On multivariate analysis, duration of symptoms, treatment group (CSORN vs. SPORT) or insurance type (public/Medicare/Medicaid vs. Private/Employer) predicted higher level of postoperative satisfaction. Baseline depression was also associated with worse Oswestry disability index at 1-year postoperative follow-up in both cohorts.Surgical DS patients treated in Canada (CSORN cohort) reported higher levels of satisfaction than those treated in the United States (SPORT cohort) despite similar to slightly worse baseline HRQOL measures. Symptom duration and insurance type appeared to impact satisfaction levels. Improvements in other patient-reported health-related quality of life measures were similar between the cohorts.

Study Design: Uncontrolled retrospective observational study. Objectives: Surgery for patients with back pain and degenerative disc disease is controversial, and studies to date have yielded conflicting results. We evaluated the effects of lumbar fusion surgery for patients with this indication in the Canadian Spine Outcomes and Research Network (CSORN). Methods: We analyzed data that were prospectively collected from consecutive patients at 11 centers between 2015 and 2019. Our primary outcome was change in patient-reported back pain at 12 months of follow-up, and our secondary outcomes were satisfaction, disability, health-related quality of life, and rates of adverse events. Results: Among 84 patients, we observed a statistically significant improvement of back pain at 12 months that exceeded the threshold of Minimum Clinically Important Difference (MCID) (mean change -3.7 points, SD 2.6, p < 0.001, MCID = 1.2; 77% achieved MCID), and 81% reported being “somewhat” or “extremely” satisfied. We also observed improvements of Oswestry Disability Index (-17.3, SD 16.6), Short Form-12 Physical Component Summary (10.3, SD 9.6) and Short Form-12 Mental Component Summary (3.1, SD 8.3); all p < 0.001). The overall rate of adverse events was 19%. Conclusions: Among a highly selective group of patients undergoing lumbar fusion surgery for degenerative disc disease, most experienced a clinically significant improvement of back pain as well as significant improvements of disability and health-related quality of life, with high satisfaction at 1 year of follow-up. These findings suggest that surgery for this indication may provide some benefit, and that further research is warranted.

OBJECTIVE Previous works investigating rates of adverse events (AEs) in spine surgery have been retrospective, with data collection from administrative databases, and often from single centers. To date, there have been no prospective reports capturing AEs in spine surgery on a national level, with comparison among centers. METHODS The Spine Adverse Events Severity system was used to define the incidence and severity of AEs after spine surgery by using data from the Canadian Spine Outcomes and Research Network (CSORN) prospective registry. Patient data were collected prospectively and during hospital admission for those undergoing elective spine surgery for degenerative conditions. The Spine Adverse Events Severity system defined minor and major AEs as grades 1–2 and 3–6, respectively. RESULTS There were 3533 patients enrolled in this cohort. There were 85 (2.4%) individual patients with at least one major AE and 680 (19.2%) individual patients with at least one minor AE. There were 25 individual patients with 28 major intraoperative AEs and 260 patients with 275 minor intraoperative AEs. Postoperatively there were 61 patients with a total of 80 major AEs. Of the 487 patients with minor AEs postoperatively there were 698 total AEs. The average enrollment was 321 patients (range 47–1237 patients) per site. The rate of major AEs was consistent among sites (mean 2.9% ± 2.4%, range 0%–9.1%). However, the rate of minor AEs varied widely among sites—from 7.9% to 42.5%, with a mean of 18.8% ± 9.7%. The rate of minor AEs varied depending on how they were reported, with surgeon reporting associated with the lowest rates (p < 0.01). CONCLUSIONS The rate of major AEs after lumbar spine surgery is consistent among different sites but the rate of minor AEs appears to vary substantially. The method by which AEs are reported impacts the rate of minor AEs. These data have implications for the detection and reporting of AEs and the design of strategies aimed at mitigating complications.

We investigated for potential predictors of outcome following degenerative lumbar spinal stenosis surgery. In this longitudinal study of 529 patients, approximately one in three patients experienced a poor clinical outcome. Demographic, health, and clinical factors were more predictive of clinical outcome than surgery-related factors., Study Design. Longitudinal analysis of prospectively collected data. Objective. Investigate potential predictors of poor outcome following surgery for degenerative lumbar spinal stenosis (LSS). Summary of Background Data. LSS is the most common reason for an older person to undergo spinal surgery, yet little information is available to inform patient selection. Methods. We recruited LSS surgical candidates from 13 orthopedic and neurological surgery centers. Potential outcome predictors included demographic, health, clinical, and surgery-related variables. Outcome measures were leg and back numeric pain rating scales and Oswestry disability index scores obtained before surgery and after 3, 12, and 24 postoperative months. We classified surgical outcomes based on trajectories of leg pain and a composite measure of overall outcome (leg pain, back pain, and disability). Results. Data from 529 patients (mean [SD] age = 66.5 [9.1] yrs; 46% female) were included. In total, 36.1% and 27.6% of patients were classified as experiencing a poor leg pain outcome and overall outcome, respectively. For both outcomes, patients receiving compensation or with depression/depression risk were more likely, and patients participating in regular exercise were less likely to have poor outcomes. Lower health-related quality of life, previous spine surgery, and preoperative anticonvulsant medication use were associated with poor leg pain outcome. Patients with ASA scores more than two, greater preoperative disability, and longer pain duration or surgical waits were more likely to have a poor overall outcome. Patients who received preoperative chiropractic or physiotherapy treatment were less likely to report a poor overall outcome. Multivariable models demonstrated poor-to acceptable (leg pain) and excellent (overall outcome) discrimination. Conclusion. Approximately one in three patients with LSS experience a poor clinical outcome consistent with surgical non-response. Demographic, health, and clinical factors were more predictive of clinical outcome than surgery-related factors. These predictors may assist surgeons with patient selection and inform shared decision-making for patients with symptomatic LSS. Level of Evidence: 2