Evaluating the analgesic effect of the perioperative perineural infiltration of bupivacaine and clonidine at the site of injury following lower extremity amputation

Summary 

Background

Pain following amputation surgery represents a significant source of morbidity and may lead to an increased incidence of phantom limb pain. Regional analgesic techniques designed to reduce acute and chronic pain following amputation surgery have yielded conflicting results. Clonidine, an α-2 agonist, may provide for a reduction in acute and chronic pain following nerve injury in the rat model. This study was designed to examine the effect of perineural infiltration of clonidine on acute and chronic pain following lower extremity amputation.

Methods

Eighty patients undergoing lower extremity amputation received a perineural injection of 10mL bupivacaine 0.25% and clonidine 100μg (n=40) or 10mL normal saline (n=40) prior to nerve transection. Pain scores and opioid use were recorded for the first 72h postoperatively. One year after surgery, patients were contacted to determine the incidence of phantom limb and stump pain.

Results

Patients receiving perineural bupivacaine and clonidine reported lower pain scores and consumed less opioids during the first postoperative day. There were no differences in pain scores or opioid use on postoperative days 2 or 3. There were no differences in the incidence of phantom limb pain (86% versus 82%) or stump pain (34% versus 29%) in the perineural clonidine infiltration group compared to the control group, respectively.

Conclusions

The perineural infiltration of bupivacaine and clonidine at the site of nerve transection results in a reduction in acute pain but has no effect on the incidence of long-term phantom limb or stump pain following lower extremity amputation.

Keywords: Phantom pain, Neuropathic pain, Clonidine, Amputation, Perineural analgesia