Effect of Intraoperative Infiltration With Bupivacain on the Development of Chronic Pain After Inguinal Hernia Repair

264 patients scheduled for an inguinal hernia repair using one of three procedures (Lichtenstein, Barwell and TEP = total extraperitoneal hernioplasty) are being randomly allocated intra-operatively into two groups. Group I patients receive a local injection of 20ml Carbostesin® 0.25% at the end of the operation according to a standardised procedure. Group II patients get a 20 ml placebo (0.9% Saline) injection. We use pre-filled identically looking syringes for blinded injection, i.e. the patient, the surgeon and the examinator who performs the postoperative clinical follow-ups remain unaware of group allocation. The primary outcome of the study is the occurrence of developing chronic pain (defined as persistent pain at 3 months FU) measured by VAS and Pain Matcher® device (Cefar Medical AB, Lund, Sweden). In addition to a sample size re-evaluation three interim analyses are planned after 120, 180 and 240 patients had finished their 3-months follow-up to allow for early study termination.