Learning curve of full-endoscopic technique through interlaminar approach for L5/S1 disk herniations

Although minimally invasive full-endoscopic (FE) spine surgery through the interlaminar approach has proved safe and effective for surgical treatment of lumbar disk herniation, the learning curve of the procedure has not been sufficiently established. The purpose of this study is to determine the learning curve for the FE surgery through interlaminar approach for treating the L5/S1 disk herniation. Thirty-six patients with lumbar disk herniation (L5/S1 segment) who underwent FE lumbar discectomy through the interlaminar approach between March 2011 and March 2012 were equally divided into Group A, B, and C by the study time of the surgeons. Clinical evaluation data included perioperative parameters (operative duration, intraoperative blood loss, and the amount of intraoperative bone and ligament excision), clinical curative effect index [visual analog scale (VAS) score for leg and back pain], complications, and the rate of conversion to open surgery. The operation duration, intraoperative bleeding, and the amount of bone and ligament excision were gradually and significantly reduced in the Groups A, B, and C (P < 0.01) and reflected in steep curves of proficiency suggesting that the rate of learning was fast. The VAS scores of leg and back pain were significantly improved (P < 0.01) and no symptomatic recurrence was noticed during the follow-up period (1-1.5 years). The outcomes the three groups were not significantly different. The clinical outcomes of the minimally invasive surgery for the treatment of L5/S1 segment disk herniation through the interlaminar approach were excellent suggesting of a satisfactory curative effect. The steep learning curves of perioperative parameters plotted against the number of surgeries conducted suggest that proficiency can be reached reasonably fast.