Effectiveness of total extraperitoneal hernia correction for clinically occult inguinal hernia (effect-trial) – a multicentre randomized controlled trial

Abstract Background Groin pain in adults is a common complaint in surgical practice, often related to an inguinal hernia (IH). An IH is occult when it is detected on ultrasound, but the patient does not manifest any clinical signs. Current international guidelines lack specific recommendations for managing occult IH accompanied by groin pain, potentially leading to unnecessary surgical interventions and inadequate patient counselling. This multicentre randomized controlled trial aimed to determine whether watchful waiting (WW) is non-inferior to totally extraperitoneal (TEP) repair in terms of pain for this condition. Method The primary outcome was the difference in pain scores between baseline and 3 months of follow-up, measured at rest and during exercise, in patients with groin pain and occult IH. Total follow-up was 12 months. Secondary outcomes included quality of life, patient satisfaction and cross over. Results Ninety-nine patients were randomized, of which 14 participants had withdrawn before treatment. A total of 85 patients (TEP repair n = 36, WW n = 49) were included in an as-treated analysis. At three months of follow-up, the difference in pain scores at rest (p = 0.691) and during exercise (p = 0.139) were comparable between both groups. Equivalence tests were significant for the primary outcome (p < 0.001), which indicated similarity. After three months, six patients (12%) crossed over from the conservative to the operative arm. Other outcome parameters were not significantly different. Conclusion The EFFECT-trial suggests that WW is non-inferior to TEP repair regarding pain 3 months after the start of treatment in patients with groin pain and occult IH.