INITIAL NORTH-AMERICAN EXPERIENCE WITH BOTULINUM TOXIN TYPE-A FOR TREATMENT OF ANISMUS

PURPOSE: Botulinum toxin type A (BTX-A), produced by Clostridium botul inum, is a potent neurotoxin. The purpose of this study was to evaluat e the efficacy of BTX-A for treatment of anismus. MATERIALS AND METHOD S: All patients treated with BTX-A for anismus were evaluated. Eligibi lity criteria included a history of chronic assisted evacuation (laxat ives, enemas, or suppositories), demonstration of anismus by cinedefec ogram and electromyography, and failure of a minimum of three sessions of supervised biofeedback therapy (BF). Contingent on body mass, 6 to 15 units of BTX-A was injected bilaterally under electromyography gui dance into the external sphincter or the puborectalis muscle. Treatmen t was repeated as necessary for a maximum of three sessions during a t hree-month period. Success was considered as discontinuation of evacua tory assistance and was evaluated between one and three months and aga in at up to one year. RESULTS: Between July 1994 and May 1995, four pa tients ranging from 29 to 82 years in age (2 females, 2 males) had ani smus that failed to respond to between 3 and 15 biofeedback sessions. All patients improved between one and three months after BTX-A injecti on, and two had sustained improvement for a range of three months to o ne year. There was no morbidity or mortality associated with BTX-A inj ection. CONCLUSIONS: BTX-A is extremely successful for temporary treat ment of anismus that is refractory to BF management. However, because the mechanism of action is short, longer term results are only 50 perc ent successful. Hopefully, modifications in the strain of BTX-A and do se administered will allow longer periods of success or a repeat trial of BF. Nonetheless, this preliminary report is very encouraging in of fering a method of managing this recalcitrant condition.