Open Preperitoneal Inguinal Hernia Repair, TREPP versus TIPP in a Randomized Clinical Trial: Abstract provisionally accepted for ESA congress May 2021 Cologne, titled 'Chronic inguinal pain after the TransREctus sheath preperitoneal method compared to the TransInguinal preperitoneal technique. A randomized clinical trial'

OBJECTIVE The aim of this study was to compare chronic postoperative inguinal pain (CPIP) in patients with an inguinal hernia after the TransREctus Sheath PrePeritoneal (TREPP) and the TransInguinal PrePeritoneal Technique (TIPP). BACKGROUND The preperitoneal mesh position for inguinal hernia repair showed beneficial results regarding CPIP with low recurrence rates. Two open preperitoneal techniques, TREPP and TIPP, were compared in a randomized clinical trial with the hypothesis of fewer patients with CPIP after TREPP due to complete avoidance of nerve contact. METHODS Adult patients with a primary unilateral inguinal hernia were randomized to either TREPP or TIPP in four hospitals. Before the trial's start the study protocol was ethically approved and published. Outcomes included CPIP after 1 year (primary outcome) and recurrence rates, adverse events, and health-related quality of life (secondary outcomes). Follow-up was performed at 2 weeks, 6 months, and 1 year. RESULTS Baseline characteristics were comparable in both groups. Pain was less often present after TREPP at 2 weeks and 6 months, but CPIP at rest at 1 year was comparable: 1.9% after TREPP vs 1.4% after TIPP, P = 0.535). The overall recurrence rate was higher in the TREPP group, 8.9% vs 4.6%, P = 0.022). Corrected for a learning curve for TREPP, no significant difference could be assessed (TREPP 5.7% and TIPP 4.8%, P = 0.591). CONCLUSION Both the TREPP and TIPP technique resulted in a low incidence of CPIP after 1-year follow-up. The TREPP method can be considered a solid method for inguinal hernia repair if expertise is present. The learning curve of the TREPP techniques needs further evaluation. TRIAL REGISTRATION ISRCTN18591339.