Randomized clinical trial of postoperative subfascial infusion with bupivacaine following ambulatory open mesh repair of inguinal hernia.

BACKGROUND: Wound pain remains the commonest problem after ambulatory open repair of inguinal hernia. Postoperative subfascial infusion of the wound with bupivacaine extends local analgesia at home and may achieve superior analgesia compared with oral analgesics alone. The objective of the present trial was to evaluate the efficacy of postoperative subfascial infusion of the wound with 0.5% bupicavaine at 2 ml per hour for 48 h after operation. METHODS: Forty-four patients who underwent ambulatory open tension-free mesh hernioplasties were randomized to two arms of treatment. The pump group had an infusion pump containing 100 ml 0.5% bupivacaine being placed between the external oblique aponeurosis and the Prolene mesh, whereas the nonpump group was treated with oral analgesics alone. Assuming that an observed difference of 2.0 existed between the mean pain scores of the two groups, the estimated sample size would be at least 20 patients in each group. RESULTS: Postoperative pain scores at rest and on coughing were significantly lower in the pump group than in the nonpump group on days 0 and 1 after surgery (p < 0.01). Before being discharged, none of the pump group patients requested analgesics, but 6 patients of the nonpump group required analgesic supplement (p = 0.025). Ten patients (50%) of the pump group experienced no pain during the period of bupivacaine infusion. Recovery variables, including time taken to resume ambulation and micturition, were comparable between the two groups. The pump and nonpump group patients returned to their normal activities after a median of 3 and 4 days, respectively (p = 0.217). The postoperative morbidity rates of the two groups were similar. CONCLUSION: Postoperative subfascial infusion of the wound with 0.5% bupivacaine achieved superior analgesia compared with oral analgesics alone. Portable infusion pump is a safe technique to continue local analgesia at home after ambulatory open repair of inguinal hernia. The drawbacks of the ON-Q Pain Management System included its high cost and frequent seepage of blood-stained anesthetic fluid into the wound dressing.