Surgeons Learning Curve of Transforaminal Endoscopic Discectomy for Sciatica

Abstract

Objective: Full-endoscopic spine surgery is gaining interest as a less-invasive alternative to treat sciatica caused by a lumbar disc herniation. Concerns, however, exist with the learning curve as percutaneous transforaminal endoscopic discectomy (PTED) appears to be more difficult to be performed compared to other techniques. In this study, the clinical outcomes during and after the learning curve are presented of 3 surgeons naïve to PTED.

Methods: In the first phase of a randomized controlled, noninferiority trial comparing PTED with microdiscectomy, 3 surgeons were trained in the PTED-procedure by a senior surgeon. After performing up to 20 cases under supervision, they started performing PTED on their own. Results of the early cases were compared to the later cases (>20). Furthermore, complications and reoperations were compared. Finally, differences in clinical outcomes between surgeons were compared.

Results: At 12 months of follow-up, 87% of the patients had follow-up data available. In general, there were no significant differences in patient-reported outcomes between the early and later PTED cases. Furthermore, outcomes of the early PTED cases were comparable to the outcomes of microdiscectomy, while the later PTED cases had small, but more favorable outcomes compared to microdiscectomy. Two learning curve surgeons had substantially higher rates of reoperations within 1 year, compared to the senior surgeon or the microdiscectomy group. Duration of surgery was also longer for all learning curve surgeons. Finally, when comparing clinical outcomes of patients undergoing PTED versus microdiscectomy, there appears to be some statistically significant differences in outcomes compared between the senior and 3 learning curve surgeons.

Conclusion: PTED appears to be safe to be adopted by surgeons naïve to the procedure when they are initially supervised by an experienced senior surgeon. Duration of surgery and risk of repeated surgery are increased during the learning curve, but patient-reported outcomes of the early PTED cases are similar to the outcomes of later PTED cases, and similar to the outcomes of microdiscectomy cases. This study underlines the need for an experienced mentor for surgeons to safely adopt PTED.

Keywords: Endoscopic discectomy; Lumbar disc herniation; Randomized controlled trial; Sciatica.

Fig. 1.

Flowchart with an overview of the enrollment and follow-up during the PTED-study. PTED, percutaneous transforaminal endoscopic discectomy; LDH, lumbar disc herniation.

Fig. 2.

Analysis of the duration of surgery through scatterplots and basic control charts.

Fig. 3.

Subgroup analyses of the clinical outcomes of the experienced surgeon, compared to the outcomes of the 3 other surgeons during the learning curve phase. Outcomes regarding the VAS for leg pain (A), VAS for back pain (B), ODI (C), and QoL(D) are shown. PTED, percutaneous transforaminal endoscopic discectomy; OM, open microdiscectomy; CI, confidence interval; VAS, visual analogue scale; ODI, Oswestry Disability Index; OoL, quality of life.