Perineural morphine in patients with chronic ischemic lower extremity pain: efficacy and long-term results.

To compare the efficacy, safety, and impact on daily activity of peripherally administered morphine plus a local anesthetic with that of a local anesthetic alone in patients with chronic ischemic lower extremity pain. Fifty patients with lower extremity ischemic pain due to peripheral vascular disease who had undergone surgical sympathectomy and who were not responding to systemic analgesics were included. Study treatments were bupivacaine plus morphine or bupivacaine alone administered via popliteal catheter. Each patient received both study treatments consecutively, with a washout period, in a double-blind fashion. The effects of treatments on pain severity (numerical rating scale), duration of analgesia, and daily activity were evaluated. Then, patients were asked to state which one of the treatments they preferred for the long term, during which catheter outcomes were evaluated. Both treatments provided significant pain control compared to baseline at all time points, both at rest and during activity. However, the combination treatment provided superior pain control at 8 and 12 h, and longer analgesia duration (12 ± 2 h vs 9 ± 1 h; P < 0.001). During the long term, treatments were similar in terms of analgesia. The combination treatment had a higher incidence of side effects (30% vs 0%; P < 0.001). A peripherally administered bupivacaine plus morphine combination provided better and longer analgesia for ischemic pain compared to bupivacaine alone for the short term, but not for the long term. On the other hand, our results show that continuous popliteal treatment is an effective, safe, and comfortable modality for long-term use in the home setting for patients with intractable chronic pain. [ABSTRACT FROM AUTHOR]