Watchful waiting versus totally extraperitoneal (TEP) hernia repair for occult inguinal hernia and pain (EFFECT trial)—a multicenter, non-inferiority, randomized controlled trial

Background: Current international guidelines offer no specific recommendations for managing occult inguinal hernias with groin pain, often resulting in unnecessary repairs. This randomized controlled trial (RCT) evaluated whether watchful waiting (WW) is non-inferior to totally extraperitoneal (TEP) repair in this distinct patient population. Methods: From December 29, 2017, to March 4, 2022, this multicenter, non-inferiority RCT screened all adult patients with unilateral groin pain (numeric rating scale [NRS] ≥ 1) without a clinically evident inguinal hernia. Patients allocated to the WW arm were treated with rest, analgesics, or physiotherapy, while those assigned to surgery underwent TEP repair. The sample size was 80 patients per arm (non-inferiority margin: 0.75 NRS; 1-sided alpha: 0.025; beta: 0.10; loss to follow-up: 10%). The primary outcome was the mean NRS difference between baseline and 3 months of follow-up, measured at rest and during exercise, and analyzed using a mixed-effects model. Total follow-up was 12 months. Secondary outcomes included quality of life, patient satisfaction, and crossover rate. Results: From a total of 99 patients, 85 patients were included in the study (WW: 49; TEP: 36). The analysis showed a mean difference of 0.644 (97.5% CI: − 0.321 to 1.610) for pain at rest and 0.806 (97.5% CI: − 0.402 to 2.014) for pain during exercise. Crossover from WW to TEP occurred in five patients (10%). Secondary outcomes were similar between the groups up to 3 months. Conclusion: This trial failed to demonstrate non-inferiority of WW compared to TEP repair for pain relief at 3 months post-intervention in patients with groin pain and an occult inguinal hernia. However, this result does not confirm that WW is inferior, as secondary outcomes were comparable up to 3 months and upfront TEP repair carried a risk of overtreatment. Therefore, a WW strategy for at least 3 months may be justified as a diagnostic tool to determine which patients may benefit from surgery.