Preoperative local infiltration with ropivacaine for postoperative pain relief after inguinal hernia repair. A randomised controlled trial

Abstract

Objective: To assess the effect of preoperative local anaesthesia with ropivacaine and find out if there was a dose-response relationship with postoperative pain after inguinal hernia repair.

Design: Randomised, double-blind, placebo-controlled trial.

Setting: Two Swedish and two Norwegian hospitals.

Subjects: 131 Male patients undergoing elective inguinal hernia repair.

Intervention: Infiltration of the inguinal field before operation with 0.5% ropivacaine 40 ml (200 mg), 0.25% ropivacaine 40 ml (100 mg) or saline 40 ml.

Main outcome measures: Wound pain at rest and during mobilisation, pressure exerted to reach pain threshold and maximum pain tolerance after 3, 6, 10, and 24 hours, and after 7 days; consumption of analgesics; and Quality of Life assessed by two independent questionnaires before and after operation.

Results: Pain scores after 3 hours were significantly lower in the ropivacaine groups compared with the saline group for all variables (p < 0.05). At 6 hours pain scores were significantly lower for ropivacaine 0.5% compared with saline for wound pain during mobilisation and pressure exerted to reach maximum pain tolerance. Patients given saline made their first request for analgesics significantly sooner than in the other two groups (p < 0.05), and a significantly larger percentage of them requested analgesics during the first 24 hours (p < 0.05). Evaluation of the Quality of Life questionnaires showed no significant differences between the groups.

Conclusion: Ropivacaine has a significant, dose-related pain-reducing effect in the immediate postoperative period but we could find no support for the theory that preoperative infiltration analgesia reduces long term pain.