Analgesic effects of botulinum toxin A: a randomized, placebo-controlled clinical trial

Postoperative pain in children with spastic cerebral palsy (CP) is often at tributed to muscle spasm and is difficult to manage using opiates and benzo diazepines. Adductor-release surgery to treat or prevent hip dislocation in children with spastic CP is frequently performed and is often accompanied by severe postoperative pain and spasm. A double-blinded, randomized, place bo-controlled clinical trial of 16 patients (mean age 4.7 years) with a mai nly spastic type of CP (either diplegic or quadriplegic in distribution) wa s used to test the hypothesis that a significant proportion of postoperativ e pain is secondary to muscle spasm and, therefore, might be reduced by a p reoperative chemodenervation of the target surgical muscle by intramuscular injection of botulinum toxin A (BTX/A). Compared with the placebo, BTX/A w as found to be associated with a reduction in mean pain scores of 74% (P<0. 003), a reduction in mean analgesic requirements of approximately 50% (P<0. 005), and a reduction in mean length of hospital admission of 33% (P<0.003) . It was concluded that an important component of postoperative pain in the patient population is due to muscle spasm and this can be managed effectiv ely by preoperative injection with BTX/A. These findings may have implicati ons for the management of pain secondary to muscle spasm in other clinical settings.