Initial learning curve after switching to uniportal endoscopic discectomy for lumbar disc herniations.

PURPOSE

The purpose was to investigate the learning curve for elective endoscopic discectomy performed by a single surgeon who made a complete switch to uniportal endoscopic surgery for lumbar disc herniations in an ambulatory surgery center and determine the minimum case number required to safely overcome the initial learning curve.

METHODS

Electronic medical records (EMR) of the first 90 patients receiving endoscopic discectomy by the senior author in an ambulatory surgery center were reviewed. Cases were divided by approach, transforaminal (46) versus interlaminar (44). Patient-reported outcome measures (visual-analog-score (VAS) and the Oswestry disability index (ODI)) were recorded preoperatively and at 2-week, 6-week, 3-month, and 6-month appointments. Operative times, complications, time to discharge from PACU, postoperative narcotic use, return to work, and reoperations were compiled.

RESULTS

Median operative time decreased approximately 50% for the first 50 patients then plateaued for both approaches (mean: 65 min). No difference in reoperation rate observed during the learning curve. Mean time to reoperation was 10 weeks, with 7(7.8%) reoperations. The interlaminar and transforaminal median operative times were 52 versus 73 min, respectively (p = 0.03). Median time to discharge from PACU was 80 min for interlaminar approaches and 60 min for transforaminal (p < 0.001). Mean VAS and ODI scores 6 weeks and 6 months postoperatively were statistically and clinically improved from preoperatively. The duration of postoperative narcotic use and narcotics need significantly decreased during the learning curve as the senior author realized that narcotics were not needed. No differences were apparent between groups in other metrics.

CONCLUSIONS

Endoscopic discectomy was shown to be safe and effective for symptomatic disc herniations in an ambulatory setting. Median operative time decreases by half over the first 50 patients in our learning curve, while reoperation rates remained similar without the need for hospital transfer or conversion to an open procedure in an ambulatory setting.

LEVEL OF EVIDENCE

Level III, prospective cohort.