Transforaminal endoscopic lumbar discectomy: learning curve of a single surgeon

Background: Transforaminal endoscopic lumbar discectomy (TELD) has well-recognized advantages and disadvantages in the literature. Some of the mentioned disadvantages are insufficient discectomy, higher recurrence rate and long learning curve (LC). The objective of this study is to describe the LC and analyze the survival rate of patients operated through TELD. Methods: Retrospective study of 41 cases operated through TELD by the same surgeon from June 2013 to January 2020, with a minimum follow-up of 6 months. Demographic data and information on operative time (OT), complications, hospital stay, hernia recurrence and reoperations were collected. LC of the TELD was analyzed using a cumulative sum (CUSUM) test for parameter stability for linear regression coefficients, using the CUSUM from recursive residuals. Results: Thirty-nine patients, 24 men (61.54%) and 15 women (38.46%), were included in the present cohort, and a total of 41 TELD were performed. The average OT was 96 minutes (SD =30) and the CUSUM of the recursive residuals shows learning of the TELD in the case 20. The mean OT in the first 20 cases was 114 minutes (SD =30) versus 80 minutes (SD =17) in the last 21 cases (P=0.0001). The rates of recurrent Dh were 17%, and 12% need reoperation. Conclusions: We consider that the LC of TELD requires operating 20 cases to perform the procedure with a significant reduction in OT, with minimal rates of reoperation and complications.