Perineural bupivacaine injection reduces inguinodynia after inguinal hernia repair

Background Inguinodynia, defined as pain lasting >3 months after inguinal hernia repair, remains the major complication of hernia operation. We sought to determine the effect of direct perineural infiltration on acute pain and inguinodynia after open inguinal hernia repair. Methods Patients who presented with an inguinal hernia at a university teaching hospital were evaluated prospectively and randomized to either (1) percutaneous ilioinguinal nerve block or (2) percutaneous ilioinguinal nerve block with additional perineural infiltration of the ilioinguinal, iliohypogastric, genitofemoral nerves. All patients in each group received a total of 12 mL of 0.5% bupivacaine. Self-reported faces of pain level (1–10), minutes to discharge from the recovery room, narcotic quantity consumed (oxycodone 5 mg/paracetamol 325 mg), days on narcotics, and incidence of inguinodynia at 3 months were all recorded. Results Ninety-two patients were randomized in the study. Patients who received perineural bupivacaine infiltration of nerves had less recovery room pain (1.3 vs 3.9, P < .001) and shorter recovery discharge times (89 vs 105 min, P = .047) and consumed fewer narcotics (9.7 vs 15.1 doses, P = .010). The incidence of inguinodynia at 3 months was less in the treatment group (8.2% vs 27.9%, P = .013). Conclusion We have implemented a novel and inexpensive method of local nerve blockade that decreases pain immediately after operation and at 3 months postoperatively. Furthermore, our method leads to shorter recovery room stay and fewer narcotics after operation.