The objective of this study is to determine if Myobloc significantly decreases prosthesis-associated symptomatic sweating in amputees when compared to a saline solution placebo. The study is randomized, double-blind, placebo-controlled, crossover trial with a total enrollment of 32 amputee subjects.

Patients with amputations experience severe sweating due to sockets and liners used with fitted prostheses. This excessive sweating causes inadequate fitting and function of the prosthesis as well as discomfort.

The treatment modality and techniques used are based upon a successful prior open-labeled pilot study done by this research group investigating the effect of Botulinum Toxin A (BOTOX) on residual limb hyperhidrosis, which demonstrated significant decreases in sweating in amputees with residual limb hyperhidrosis treated with BOTOX.

Each subject will undergo baseline testing consisting of 15 minutes of walking on a treadmill (or using a handcycle) at light exertion (11 on the Berg scale). They will report the effect of sweating on their prosthesis fit and function over the past month, and the amount of sweat produced in the 15 minutes will be measured via gravimetric assessment. At the end of the baseline session, subjects receive either the drug or placebo by injection into the residual limb area they identify as being the most troublesome for sweating. Subjects return for a 1-month follow-up session where the questionnaire, walking test, and sweat collection are re-administered. At the one-month follow-up session, subjects who received the placebo and felt it was not successful in decreasing their sweating are given the opportunity to cross-over into the drug arm of the trial.

Inclusion Criteria:

• Male or female, 18-50 years of age, active duty or retired military
• Limb amputation (single or multiple:for lower extremity amputees, amputation at the ankle or above; for upper extremity amputees, amputation at the wrist or above)
• Clear history of excessive sweating in a residual limb that is interfering with prosthesis fitting and functioning. This will be defined as focal, visible sweating in the region of the residual limb with at least one of the following characteristics: impairs prosthesis fitting, impairs functioning with a limb prosthesis
• Negative urine pregnancy test prior to the administration of study medication (for females)

Exclusion Criteria:

• Age less than 18 or greater than 50
• Any medical condition that may put the participant at increased risk with exposure to Myobloc, including diagnosed myasthenia gravis, Eaton-Lambert syndrome, amyotrophic lateral sclerosis/motor neuron disease, neuropathy, renal stones, or any other disorder that may interfere with neuromuscular function
• Females who are pregnant, breast feeding, or planning a pregnancy during the study, or who think they may be pregnant at the start of the study
• Known allergy or sensitivity to any of the components in the study medication
• Known sensitivity to human albumin or albumin transfusions
• Current or planned use of aminoglycosides
• Systemic medical conditions (such as thyroid disease, hypertension, bleeding disorders, diabetes, cancers, etc.) that are not currently medically managed or controlled
• Current or planned use of a myoelectric prostheses (for upper extremity amputees), as the potential for weakness caused by botulinum toxin could interfere with muscle contraction
• Concurrent participation in another investigational drug or device study, or participation in the 30 days immediately prior to study enrollment
• Any condition or situation, in the investigator's opinion, that may put the participant at significant risk, confound the study results, or interfere significantly with the participant's ability to participate in the study
• Any previous use of Myobloc, Dysport, or BOTOX