Randomized prospective study comparing preoperative epidural and intraoperative perineural analgesia for the prevention of postoperative stump and phantom limb pain following major amputation

Background and Objectives. Acute stump pain and phantom limb pain after amp utation is a significant problem among amputees with a reported incidence o f phantom limb pain in the first year following amputation as high as 70%. Epidural analgesia before limb amputation is commonly used to reduce postam putation acute stump pain in the immediate postoperative period and phantom pain in the first year. We investigated whether immediate postamputation s tump pain and phantom pain in the first year is reduced by preoperative epi dural block with bupivacaine and diamorphine compared with intraoperative p lacement of a perineural catheter infusing bupivacaine. Methods: In a randomized prospective trial, 30 patients scheduled for lower limb amputation were randomly assigned epidural bupivacaine at the standar d rate used in our hospital (0.166%, 2 to 8 mL/h) and diamorphine (0.2 to 0 .8 mg/h) for 24 hours before and during operation (14 patients; epidural gr oup) and 3 days postoperatively, or an intraoperatively placed perineural c atheter (16 patients; perineural group) for intra and postoperative adminis tration of bupivacaine (0.25%, 10 mL/h). All patients had general anesthesi a for the amputation and were asked about stump and phantom pain in the fir st 3 days and then at 6 and 12 months by an independent examiner. Study end points were rate of stump and phantom pain, intensity of stump and phantom pain, and consumption of opioids. The groups were well matched in baseline characteristics. Results: Stump pain scores in the first 3 days were significantly higher in the perineural group compared with the epidural group (P < .01). After 3 d ays, 4 (29%) patients in the epidural group and 7 (44%) in the perineural g roup had phantom pain (P = .32). Numbers of patients with phantom pain for epidural versus perineural group were: 5 (63%) versus 7 (88%) (P = .25) at 6 months; 3 (38%) versus 4 (50%) (P = .61) at 12 months. Stump pain and pha ntom sensation were similar in both groups at 6 and 12 months. Conclusions: Using our regimen, perioperative epidural block started 24 hou rs before the amputation is not superior to infusion of local anaesthetic v ia a perineural catheter in preventing phantom pain, but gives better relie f of stump pain in the immediate postoperative period.