Open AccessAmbulatory continuous peripheral nerve blocks to treat postamputation phantom limb pain: a multicenter, randomized, quadruple-masked, placebo-controlled clinical trial
Author(s) -
Brian M. Ilfeld,
Bahareh Khatibi,
Kamal Maheshwari,
Sarah J. Madison,
Wael Ali Sakr Esa,
Edward R. Mariano,
Michael L. Kent,
Steven Hanling,
Daniel I. Sessler,
James C. Eisenach,
Steven P. Cohen,
Edward J. Mascha,
Chao Ma,
Jennifer Padwal,
Alparslan Turan,
PAINfRE Investigators
Publication year - 2020
Publication title -
pain
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.524
H-Index - 258
eISSN - 1872-6623
pISSN - 0304-3959
DOI - 10.1097/j.pain.0000000000002087
Subject(s) - phantom pain , medicine , anesthesia , interquartile range , placebo , crossover study , phantom limb , randomized controlled trial , local anesthetic , amputation , surgery , alternative medicine , pathology
Phantom limb pain is thought to be sustained by reentrant neural pathways, which provoke dysfunctional reorganization in the somatosensory cortex. We hypothesized that disrupting reentrant pathways with a 6-day-long continuous peripheral nerve block reduces phantom pain 4 weeks after treatment. We enrolled patients who had an upper- or lower-limb amputation and established phantom pain. Each was randomized to receive a 6-day perineural infusion of either ropivacaine or normal saline. The primary outcome was the average phantom pain severity as measured with a Numeric Rating Scale (0-10) at 4 weeks, after which an optional crossover treatment was offered within the following 0 to 12 weeks. Pretreatment pain scores were similar in both groups, with a median (interquartile range) of 5.0 (4.0, 7.0) for each. After 4 weeks, average phantom limb pain intensity was a mean (SD) of 3.0 (2.9) in patients given local anesthetic vs 4.5 (2.6) in those given placebo (difference [95% confidence interval] 1.3 [0.4, 2.2], P = 0.003). Patients given local anesthetic had improved global impression of change and less pain-induced physical and emotional dysfunction, but did not differ on depression scores. For subjects who received only the first infusion (no self-selected crossover), the median decrease in phantom limb pain at 6 months for treated subjects was 3.0 (0, 5.0) vs 1.5 (0, 5.0) for the placebo group; there seemed to be little residual benefit at 12 months. We conclude that a 6-day continuous peripheral nerve block reduces phantom limb pain as well as physical and emotional dysfunction for at least 1 month.