Effect of spinal decompression on back pain in lumbar spinal stenosis: a Canadian Spine Outcomes Research Network (CSORN) study.

BACKGROUND CONTEXT: Surgical decompression is usually offered for improvement of neurogenic claudication in patients with symptomatic lumbar canal stenosis. These patients often have associated low back pain (LBP) and little is known about the effect of decompression on this symptom.

PURPOSE: The goal of the present study is to specifically quantify the improvement in LBP following surgical decompression for lumbar canal stenosis and to identify factors associated with changes in LBP in this population.

STUDY DESIGN: This is a multicenter, retrospective review of consecutive spine surgery patients enrolled by the Canadian Spine Outcomes and Research Network.

PATIENT SAMPLE: Consecutive patients who underwent surgical treatment for symptomatic lumbar spine stenosis without instability between 2014 and 2017.

OUTCOME MEASURES: Change in LBP on the Numeric Rating Scale (NRS).

METHODS: Patient-reported outcomes were collected at baseline and at 3, 12, and 24 months after surgery. The primary outcome was change in LBP on the NRS. Multivariable logistic regression was used to model the relationship between the outcome and potential factors associated with achieving minimal clinical important difference in back pain using a backward selection procedure.

RESULTS: In all, 1,221 patients were included in the analysis. Mean age was 64 years and 58% were males. Baseline back pain scores were available in 1,133 patients and follow-up evaluations were available in 968/1,133 (85%) patients at 3 months, 649/903 (72%) patients at 12 months, and 331/454 (73%) at 24 months. LBP significantly improved 3 months after surgery and the improvement was sustained at 24 months (p<.001). We found that 74% of patients reached the minimal clinical important difference in back pain. Predictive factors for sustained improvement (12 and 24 months) in LBP after surgical intervention were absence of narcotic usage or compensation claims and increased severity of LBP before surgery (high NRS).

CONCLUSIONS: Alleviation of clinically significant LBP was observed at 3 months after lumbar decompression surgery for neurogenic claudication and was maintained at 12 and 24 months after surgery in the majority of patients.