Preoperative Subcutaneous Fat is an Useful Indicator for Learning Totally Extraperitoneal Repair

Background: Totally extraperitoneal (TEP) repair is a recommended procedure for inguinal hernia repair in European hernia guidelines. However, technical challenges have limited its uptake in Japan, where transabdominal preperitoneal (TAPP) repair is more common. We evaluated the association of preoperative subcutaneous fat area (preSFA) with surgical outcomes and identified factors associated with the difficulty of TEP repair. Methods: Clinical data from 62 patients undergoing TEP repair were collected retrospectively. Using the median for the preoperative subcutaneous fat index (preSFI; 45.9 cm2/m2), we classified patients as having a high SFI (HSFI) (n=31) and low SFI (LSFI) (n=31). Surgical outcomes and perioperative complications were then compared between these groups. Additionally, TEP repair was divided into five phases (e.g., Phase 1: dissection of the caudal side of the preperitoneal space), and operative time was measured during each phase. Phase 1 was divided into two sub-phases (1A: insertion of the first port, 1B: reaching Cooper's ligament). Results: Operative time was longer (133 min vs 111 min, P = 0.028) and the peritoneal injury rate was higher (35.5% vs 9.7%, P = 0.015) for the HSFI patients. Furthermore, operative time for HSFI patients was significantly longer during Phase 1 (P = 0.014) and Phase 1A (P = 0.022). Conclusions: preSFA was associated with a higher peritoneal injury rate and longer operative time in HSFI patients, suggesting that the presence of abundant subcutaneous fat increases the difficulty of TEP repair.