Effect of pre-incision skin infiltration on post-hysterectomy pain - A double-blind randomized controlled trial

In this double-blind placebo-controlled randomized trial, we compared the analgesic effect of preoperative 0.25% bupivacaine (n=21) skin infiltration with normal saline (n=19) in patients undergoing abdominal hysterectomy through a lower midline incision. All patients received postoperative patient-controlled analgesia with morphine and were followed for 72 hours. The main outcome measures were morphine consumption and pain score at rest, and the contribution of different components of pain was also assessed prospectively. No statistically significant differences were found. All except one patient (n =39) could distinguish the different characteristics of somatic and visceral pain. Visceral pain predominated in the first 48 hours. We concluded that local anaesthetic infiltration is not effective in reducing pain after abdominal hysterectomy. Effective postoperative analgesia should aim to eliminate the visceral pain component.