A Randomized Controlled Study to Evaluate the Efficacy of Noninvasive Limb Cover for Chronic Phantom Limb Pain Among Veteran Amputees

Abstract Hsiao A-F, York R, Hsiao I, Hansen E, Hays RD, Ives J, Coulter ID. A randomized controlled study to evaluate the efficacy of noninvasive limb cover for chronic phantom limb pain among veteran amputees. Objective To assess the efficacy of a noninvasive limb cover for treating chronic phantom limb pain (PLP). Design Randomized, double-blind, placebo-controlled trial. Setting Outpatient clinic. Participants We randomly assigned 57 subjects to 2 groups: true noninvasive limb cover (n=30) and sham noninvasive limb cover (n=27). Inclusion criteria included age of 18 years or greater, upper or lower extremity amputation with healed residual limb, and 3 or more episodes of PLP during the previous 6 weeks. Interventions Subjects received 2 true or sham noninvasive limb covers to be worn over the prosthesis and residual limbs 24 hours a day for 12 weeks. Main Outcome Measures Primary outcome measure was the numerical pain rating scale of PLP level (0–10). Secondary outcomes included overall pain level (0–10), PLP frequency per week, and the Veterans RAND 12-Item Health Survey (VR-12). We collected data at baseline and at 6- and 12-week follow-up visits. Results Demographic and clinical characteristics were not significantly different between groups. The true noninvasive limb cover group reported nonsignificant reductions in PLP from 5.9±1.9 at baseline to 3.9±1.7 at the 12-week follow-up. The sham noninvasive limb cover group also had nonsignificant reducations in PLP from 6.5±1.8 to 4.2±2.3. PLP did not differ significantly between the 2 groups at 6 weeks (mean difference, 0.8; 95% confidence interval [CI], −1.4 to 3) or at 12 weeks (mean difference, 0.2; 95% CI, −1.9 to 2.3). Similarly, overall pain level, PLP episodes per week, and VR-12 physical and mental health component scores did not differ between the 2 groups at 6 and 12 weeks. Conclusions A true noninvasive limb cover did not significantly decrease PLP levels or the frequency of PLP episodes per week, overall bodily pain levels, or VR-12 physical and mental health component scores compared with a sham noninvasive limb cover in our veteran amputee sample.