Learning curve of single-incision laparoscopic totally extraperitoneal repair (SILTEP) for inguinal hernia

Laparoscopic totally extraperitoneal hernia repair (TEP) is a widely used treatment for inguinal hernia. Single-incision laparoscopic TEP (SILTEP) has attracted the attention of several surgeons, given its superior cosmetic results and patient satisfaction, as well as comparable outcomes to multiport surgery. Nonetheless, no relevant studies have evaluated the learning curve (LC) of SILTEP in terms of both operation time (OT) and surgical failure. Therefore, we aimed to investigate the LC of SILTEP for inguinal hernia. Medical records of 180 patients who underwent SILTEP performed by a single surgeon from a single institution between October 2012 and November 2017 were retrospectively reviewed. The LC was analyzed using the moving average method and cumulative sum control chart (CUSUM) for OT and surgical failure. Surgical failure was defined as the need for additional ports, open conversion, severe postoperative complications (Clavien–Dindo ≥ IIIa), and recurrence. Eight patients who underwent combined surgery or bilateral hernia repair were excluded from the OT analysis. From CUSUM graphs, the study period was divided into three phases: OT-phases 1 (1st–32nd), 2 (33rd–83rd), and 3 (84th–172nd) for OT and failure-phases 1 (1st–29th), 2 (30th–58th), and 3 (59th–180th) for surgical failure. Mean OTs were statistically different in the three OT phases (64.6 vs. 50.8 vs. 35.2 min; p < 0.001). Open conversion (31.0% vs. 0% vs. 2.5%) and additional port insertion (6.9% vs. 24.1% vs. 2.5%) stabilized consecutively at failure-phases 2 and 3 (p < 0.001). Surgical failure rates decreased to 5.7% by failure-phase 3 (37.9% vs. 24.1% vs. 5.7%; p < 0.001). For an experienced laparoscopic surgeon, we estimated that approximately 60 cases are needed to overcome the LC for SILTEP in terms of both reducing OT and achieving a surgical failure rate < 10%. Further proficiency could be achieved after approximately 85 SILTEP procedures with a stable OT of approximately 35 min.