Endoscopic Disectomy: Learning Curve and Outcome Evaluation

Abstract

Background: Minimally invasive techniques for Lumbar disc surgery are becoming common. It is therefore essential that we assess their learning curve and evaluate their results before their across the board application to lumbar disc herniation surgery. Objective: This prospective study was conducted to evaluate steepness of learning curve and outcome of Endoscopic disectomy. Study Design: This is a prospective study carried out at PNS Shifa, which is a tertiary care hospital, from Jan 2011 to Jan 2013. Patient Interventions: Forty three patients underwent Endoscopic disectomy for a single level herniated disc using an interlaminar approach; all procedures were performed under general anesthesia. All patients were followed prospectively. Endoscopic system used in this study consisted of tubular dilators and an endoscope with xenon light source and HD image system from Karl Storz co. Germany. Outcome measures: Outcomes were assessed by analyzing the video of the procedure to pinpoint the areas where maximum time was spent and thus devising ways to cut down the operating time. Patient outcome was measured

by using Oswestry disability index and Macnab criteria. Results: 43 patients (29 males, 14 females) underwent Endoscopic disectomy for prolapsed lumbar intervertebral disc. Mean operating time was 70 minutes. The mean operation time for the first and last 10 cases was 140 and 58 minutes, respectively. The procedures affecting a prolonged operation time were evaluated. The time required for surgery reduced considerably after 12 cases. Follow up ranged from 3 to 15 months with a mean follow up of 10.8 months. Thirty five patients had an excellent outcome while five had a good outcome. Three patients had a poor outcome and underwent open disectomy. Five patients early in the study had to be converted to open disectomy due to technical difficulties. These cases were excluded from the study. Conclusions: Endoscopic disectomy is clinically effective and reliable. The learning curve, however, is steep. It requires at least 10-15 cases before surgeon can achieve command of the procedure.