Phantom limb pain relief by contralateral myofascial injection with local anaesthetic in a placebo-controlled study: preliminary results.

OBJECTIVE To ascertain the existence of contralateral painful muscle areas mirroring phantom pain and to evaluate the short-term effects of anaesthetic vs saline, injected contra notlaterally to control phantom and phantom limb pain. DESIGN Double-blinded cross-over study. SETTING Inpatients; rehabilitation institute. PARTICIPANTS Eight lower limb amputees with phantom limb pain in the past 6 months. INTERVENTIONS Either 1 ml of 0.25% bupivacaine or 0.9% saline injected alternately in each point with a 28-gauge needle, with 72 h between injections. Main outcome measurePhantom sensation modification and the intensity of phantom limb pain (visual analogue scale) before and after injections. RESULTS Although present, painful muscle areas in the healthy limb do not mirror the topographical distribution of phantom limb pain. Sixty minutes after the injection, a statistically significant greater relief of phantom limb pain was observed after using local anaesthetic than when using saline injection (p = 0.003). Bupivacaine consistently reduced/abolished the phantom sensation in 6 out of 8 patients. These effects on phantom sensation were not observed after saline injections. CONCLUSION Contralateral injections of 1 ml 0.25% bupivacaine in myofascial hyperalgesic areas attenuated phantom limb pain and affected phantom limb sensation. The clinical importance of this treatment method requires further investigation.