Predictors for clinical outcomes of tubular surgery for endoscopic decompression in selected patients with lumbar spinal stenosis

Abstract

Introduction: The success rate of decompression surgery for lumbar spinal stenosis (LSS) has been reported to vary from 60 to 80%. The purpose of this study was to analyze the predictors for clinical outcomes after tubular surgery for endoscopic decompression (microendoscopic decompression) for LSS.

Materials and methods: A total of 100 patients with degenerative LSS (M/F: 61/39, Age: mean 69.7 years), who underwent microendoscopic decompression and had a minimum 2-year follow-up (FU) after surgery, were reviewed. All patients suffered from leg-related symptoms predominantly without severe mechanical back pain, preoperatively. The presence of chronic arterial occlusion of the lower limbs was ruled out. The primary outcome measure was clinical evaluation at 2-year FU using the Oswestry Disability Index (ODI). Furthermore, numeric rating scales, Japanese Orthopedic Association (JOA) lumbar score and JOA Back Pain Evaluation Questionnaire were used for secondary outcome measures. Based on findings of univariable analyses, multivariable logistic regression analysis was applied to identify preoperative predictors for the clinical outcomes.

Results: Sixty-eight patients (68%) were assessed as good outcomes, on the basis of minimum clinically important difference of the ODI (13 points ≤) and final ODI score (< 30 points). The secondary outcomes were further support for the primary outcome. In multivariable logistic regression analysis, co-existence of intradiscal vacuum phenomenon with LSS (odds ratio [OR] 8.26; 95% confidence interval [95% CI] 2.32-29.34; p = 0.001) and ischemic cardiovascular comorbidities (OR, 13.3; 95% CI, 1.9-92.57; p = 0.009) were significantly associated with poor clinical outcomes.

Conclusions: We found co-existence of intradiscal vacuum phenomenon with LSS and ischemic cardiovascular comorbidity to be preoperative predictors of less favorable clinical outcomes after microendoscopic decompression in selected patients of LSS. Although the conclusion obtained from restricted state, the information would be able to help in patient selection of the tubular surgery for endoscopic decompression for LSS.

Keywords: Decompression; Lumbar spinal stenosis; Minimally invasive surgery; Predictor; Surgical outcome.