An evaluation of the learning curve for a complex surgical technique: the full endoscopic interlaminar approach for lumbar disc herniations

BACKGROUND CONTEXT: Compared with conventional microsurgical technique, the full endoscopic (FE) interlaminar approach is a more minimally invasive technique for the surgical treatment of lumbar disc herniations. Its efficacy and safety have been confirmed by numerous studies. However, a steep learning curve with the use of such a complex technique is a major concern for the initial adoption of this technique. PURPOSE: To evaluate the learning curve of using an FE interlaminar technique for the surgical treatment of lumbar disc herniation. STUDY DESIGN: A prospective study of patients with lumbar disc herniation who underwent discectomy via interlaminar approach assisted by FE instruments. PATIENT SAMPLE: Thirty patients with lumbar disc herniation underwent discectomy using an interlaminar endoscopic-only approach between 2008 and 2009. METHODS: The patients were divided into three groups of 10 sequential cases each. Group A consisted of the first 10 cases, Group B the subsequent 10 cases, and Group C the last 10 cases. The clinical evaluation data included operative time, length of hospital stay, visual analog scale (VAS) leg and back pain scores, complications, and rate of conversion to an open. RESULTS: All patients were observed prospectively for 1.61 +/- 60.22 years (range, 1.2-2.0 years). There was no measurable intraoperative bleeding and postoperative infections in the three groups. Compared with Group A, the operative time in Group B was significantly decreased (p<.001). The patients in Group C had much less operative time than in Group B (p=.002). There was no significant difference with length of hospital stay in the three groups (p=.897). The improvement of VAS leg and back pain scores in each group was similar: there was a significant improvement (p<.01) at 3 months after surgery when compared with preoperative scores, but there was no statistical difference (p>.05) in the VAS leg and back pain scores between 3 months after surgery and final follow-up. The complication rate was 12.5% for Group A, 10% for Group B, and 0% for Group C. The need for conversion to an open procedure for Group A was 20% compared with zero cases in both Groups B and C. There were no symptomatic recurrences in our study. CONCLUSIONS: Excellent clinical and minimally invasive outcomes can be obtained in the surgical treatment of lumbar disc herniation via the interlaminar approach assisted by FE technique. However, attention must be paid to the steep learning curve by using this complex technique. Imprecise anatomic orientation and manipulation inside the spinal canal are key factors in the steep learning curve. Obtaining microsurgical experience, attending workshops, and suitable patient selection can help shorten the learning curve and decrease the complications. (C) 2011 Elsevier Inc. All rights reserved.