In this randomized, double-blind, placebo-controlled crossover study, we investigated whether a peripheral nerve block could temporarily eliminate phantom and stump pain after amputation. Amputees with constant postamputation pain were included and randomized to receive a nerve block with lidocaine 2% with adrenaline or saline in a crossover design. Spontaneous phantom and stump pain and evoked responses were assessed at baseline and at fixed time-points until 120 minutes after lidocaine or saline injection. The primary outcome was the difference in absolute change between worst pain intensity, either phantom or stump pain, at baseline and at 30 minutes after lidocaine or saline injection. Twelve amputees were randomized and 9 patients were included in the analysis. The absolute change in median worst pain intensity between lidocaine and saline injection was −2.0 (interquartile range, −4.0 to 0.0) (n = 9, P = 0.12). Nine of 9 patients reported at least some pain relief after lidocaine injection compared with only 2 of 9 patients after saline injection (P = 0.02). Phantom pain intensity was significantly reduced after lidocaine compared with saline injection (P = 0.04), whereas there was no significant change in stump pain intensity between the 2 interventions (P = 0.17). In all 9 amputees, evoked responses were eliminated after lidocaine injection. Thus, our findings suggest that afferent input from the peripheral nervous system plays an important role in postamputation pain.
A peripheral nerve block reduces pain after amputation, suggesting that afferent input from the periphery must play a critical role in postamputation pain.
aDepartment of Anesthesiology and Intensive Care, Aarhus University Hospital, Aarhus, Denmark
bDanish Pain Research Center, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
cDepartment of Anesthesiology, Washington University School of Medicine, St. Louis, MO, United States
dSection for Biostatistics, Department of Public Health, Aarhus University, Aarhus, Denmark
eDepartment of Neurology, Aarhus University Hospital, Arhus, Denmark
Corresponding author. Address: Department of Anesthesiology and Intensive Care, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, Building C319, 8200 Aarhus N, Denmark. Tel.: +45 78464317. E-mail address: firstname.lastname@example.org (N.S. Buch).
Sponsorships or competing interests that may be relevant to content are disclosed at the end of this article.
Received November 23, 2018
Received in revised form December 28, 2018
Accepted January 14, 2019