Laparoscopy has become very common, but the return to normal activities is frequently delayed by postoperative pain. Although local anesthetic agents are widely used before and after incision to prevent pain, no studies evaluating the use of pre-emptive analgesia in laparoscopy have been conducted. Ke and colleagues studied the effect of local anesthesia on postoperative pain, particularly the influence of the timing of infiltration of local anesthetic agent.
Fifty-seven healthy women between 18 and 45 years of age who were scheduled for elective laparoscopy were studied. All of the laparoscopic procedures used the same techniques, and members of the surgical staff were blinded as to the use of local anesthesia. All patients received local infiltration before the incision and at incisional closure, but the patients were randomly assigned to one of three groups before induction of anesthesia. Patients in group A received 10 mL of 0.5 percent bupivacaine in the pre-incisional infiltration and saline in the post-incisional infiltration. Patients in group B received saline in the pre-incisional infiltration and bupivacaine in the post-incisional infiltration. Both pre-incisional and post-incisional infiltrations in group C contained saline.
Postoperative pain was assessed by nurse interview using a standardized pain intensity scoring scale 30 minutes after incisional closure and then at two, four and 24 hours. The use of pain medication was recorded in the recovery room, and patients were asked to record their analgesic use for the first 24 hours following surgery.
The three groups did not differ significantly in pain scores at 30 minutes, two hours or four hours following incisional closure. Patients in group A (pre-incisional bupivacaine) had the lowest pain scores and tolerated a longer delay before requesting analgesia, but these differences were not statistically significant. At 24 hours, the patients in group A reported significantly lower mean pain scores than those receiving post-incisional anesthetic or placebo. Group A patients also required less analgesia in the 24-hour period following surgery, but this difference was not statistically significant. Patients receiving post-incisional anesthetic reported greater mean pain scores at four and 24 hours than patients receiving placebo.
The authors conclude that pre-incisional infiltration of bupivacaine decreases post-laparoscopic pain and reduces the need for analgesics. However, they also conclude that the popular practice of infiltrating local anesthetic at the time of incisional closure has no beneficial effect on postoperative pain.