Botulinum toxin type B in the treatment of residual limb hyperhidrosis for lower limb amputees: a pilot study

Botulinum toxin type A is established in the treatment of hyperhidrosis. This pilot study was designed to prove the alleviating effect of botulinum toxin type B (BTX-B) in sweating of the residual limb, as BTX-B, even in low doses, is supposed to possess a more specific action in sympathetic nerves than botulinum toxin type A does at a wider radius of diffusion.

Nine lower limb amputees received 1750 U BTX-B injected at the site of maximum sweating. Before injections and 4 wks and 3 mos after, patients rated their impairments regarding sweating of the residual limb, steadiness of gait, use of the prosthetic device, quality-of-life, work performance, quality of sleep, and skin problems using a numeric rating scale (NRS; 0-10).

Sweating of the residual limb before BTX-B application was rated a median of 7 (interquartile range, 6-10) on the NRS, with significant improvements after 4 wks (NRS, 3 [2-4]; P = 0.027) and 3 mos (NRS, 3 [1-4]; P = 0.020). Impaired quality of artificial limb use likewise improved from a baseline NRS of 9 (5-9) to 2 (1-4) after 4 wks and 3 (1-4) (P = 0.027) after 3 mos, consistent with limited duration of use (P = 0.023). Steadiness of gait, quality-of-life, and work performance increased accordingly, and skin problems decreased clearly but not significantly. Unexpectedly, stump pain was also reduced (baseline: NRS, 5 [4-8]; 4 wks: NRS, 4 [3-5], P = 0.109; 3 mos: NRS, 3 [2-4], P = 0.008).

Low-dose BTX-B significantly reduced sweating of the residual limb, thereby improving the use of the artificial limb, steadiness of gait, and quality-of-life. Because this has a tremendous impact on amputees, we are in dire need for systematic, larger studies.