A six-day continuous peripheral nerve block was found to alleviate phantom limb pain, and pain-stimulated emotional and physical dysfunction for about one month.     

A study was carried to assess if an ambulatory continuous peripheral nerve block of six days would offer efficacious and lasting analgesia for the established lower and upper-extremity post-amputation phantom pain.

This randomized, parallel-arm, multicenter, quadruple-masked, placebo-controlled clinical trial enrolled participants who had a lower or upper-limb amputation and established phantom pain. Each subject was randomly divided to receive a six-day perineural administration of either normal saline or ropivacaine. The average pain severity as estimated with a Numeric Rating Scale (NRS) at four weeks, after which an optional crossover therapy was administered within 0 to 12 weeks was the major endpoint.

Both the arms displayed comparable pre-therapeutic pain scores, illustrating a median (interquartile range) of 5.0 (4.0, 7.0) for each arm. After four weeks, the average phantom pain intensity was a mean (standard deviation) of 3.0 (2.9) in individuals administered local anesthetic vs 4.5 (2.6) in individuals administered a placebo.

Subjects receiving local anesthetic illustrated improved global impression of change and reduced pain-induced physical and emotional dysfunction but were not found to differ on depression scores. In the case of individuals receiving only the first infusion (without any self-selected crossover), the median decline in pain at six months for the treated participants was 3.0 (0, 5.0) vs 1.5 (0, 5.0) for the placebo group. At 12 months, there appeared to be a little residual advantage.

Ambulatory continuous peripheral nerve block effectively minimizes postamputation limb pain and improves emotional and physical dysfunction.