ObjectiveIdentify patient subgroups defined by trajectories of pain and disability following surgery for degenerative lumbar spinal stenosis, and investigate the construct validity of the subgroups by evaluating for meaningful differences in clinical outcomes.MethodsWe recruited patients with degenerative lumbar spinal stenosis from 13 surgical spine centers who were deemed to be surgical candidates. Study outcomes (leg and back pain numeric rating scales, modified Oswestry disability index) were measured before surgery, and after 3, 12, and 24 months. Group-based trajectory models were developed to identify trajectory subgroups for leg pain, back pain, and pain-related disability. We examined for differences in the proportion of patients achieving minimum clinically important change in pain and disability (30%) and clinical success (50% reduction in disability or Oswestry score ≤22) 12 months from surgery.ResultsData from 548 patients (mean[SD] age = 66.7[9.1] years; 46% female) were included. The models estimated 3 unique trajectories for leg pain (excellent outcome = 14.4%, good outcome = 49.5%, poor outcome = 36.1%), back pain (excellent outcome = 13.1%, good outcome = 45.0%, poor outcome = 41.9%), and disability (excellent outcome = 30.8%, fair outcome = 40.1%, poor outcome = 29.1%). The construct validity of the trajectory subgroups was confirmed by between-trajectory group differences in the proportion of patients meeting thresholds for minimum clinically important change and clinical success after 12 postoperative months (p < .001).ConclusionSubgroups of patients with degenerative lumbar spinal stenosis can be identified by their trajectories of pain and disability following surgery. Although most patients experienced important reductions in pain and disability, 29% to 42% of patients were classified as members of an outcome trajectory subgroup that experienced little to no benefit from surgery. These findings may inform appropriate expectation setting for patients and clinicians and highlight the need for better methods of treatment selection for patients with degenerative lumbar spinal stenosis.

Study Design. Prospective Cohort Objective. The aim of this study was to evaluate which demographic, clinical, or radiographic factors are associated with selection for surgical intervention in patients with mild cervical spondylotic myelopathy (CSM). Summary of Background Data. Surgery has not been shown superior to best conservative management in mild CSM comparative studies; trials of conservative management represent an acceptable alternative to surgical decompression. It is unknown what patients benefit from surgery. Methods. This is a prospective study of patients with mild CSM, defined as modified Japanese Orthopaedic Association Score (mJOA) ≥15. Patients were recruited from seven sites contributing to the Canadian Spine Outcomes Research Network. Demographic, clinical, radiographic and health related quality of life data were collected on all patients at baseline. Multivariate logistic regression modeling was used to identify factors associated with surgical intervention. Results. There were 122 patients enrolled, 105 (86.0%) were treated surgically, and 17 (14.0%) were treated nonoperatively. Overall mean age was 54.8 years (SD 12.6) with 80 (65.5%) males. Bivariate analysis revealed no statistically significant differences between surgical and nonoperative groups with respect to age, sex, BMI, smoking status, number of comorbidities and duration of symptoms; mJOA scores were significantly higher in the nonoperative group (16.8 [SD 0.99] vs. 15.9 [SD 0.89], P < 0.001). There was a statistically significant difference in Neck Disability Index, SF12 Physical Component, SF12 Mental Component Score, EQ5D, and PHQ-9 scores between groups; those treated surgically had worse baseline questionnaire scores (P < 0.05). There was no difference in radiographic parameters between groups. Multivariable analysis revealed that lower quality of life scores on EQ5D were associated with selection for surgical management (P < 0.018). Conclusion. Patients treated surgically for mild cervical myelopathy did not differ from those treated nonoperatively with respect to baseline demographic or radiographic parameters. Patients with worse EQ5D scores had higher odds of surgical intervention. Level of Evidence: 3

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