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

Abstract

Postoperative pain in children with spastic cerebral palsy (CP) is often attributed to muscle spasm and is difficult to manage using opiates and benzodiazepines. 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, placebo‐controlled clinical trial of 16 patients (mean age 4.7 years) with a mainly spastic type of CP (either diplegic or quadriplegic in distribution) was used to test the hypothesis that a significant proportion of postoperative pain is secondary to muscle spasm and, therefore, might be reduced by a preoperative chemodenervation of the target surgical muscle by intramuscular injection of botulinum toxin A (BTX/A). Compared with the placebo, BTX/A was 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 effectively by preoperative injection with BTX/A. These findings may have implications for the management of pain secondary to muscle spasm in other clinical settings.

Botulinum toxin and its orthopaedic applications

“…The study by Barwood et al 51 which found a significant reduction in post-operative pain in children with cerebral palsy secondary to a reduction in muscle spasm, has implications for the management of pain secondary to muscle spasm in other circumstances. After the use of BTX injections, the relief from pain is usually due to its effect on muscle tone rather than to any theoretical direct effect on the pain fibres.…”

“…50 Other indications for BTX-A in cerebral palsy include post-operative or post-treatment control of pain. 51 The medium-and long-term effects of the use of BTX in cerebral palsy are as yet unknown. Concerns include atrophy of muscle fibres and potentiation of muscle weakness, particularly in children with pre-existing weakness masked by spasticity.…”

Assessment: Botulinum neurotoxin for the treatment of spasticity (an evidence-based review): [RETIRED]

“…One Class I 44 study using BoNT injection into the adductors and medial hamstrings showed an average improvement in knee-to-knee distance of about 9 cm (p Ͻ 0.002) and decrease in adductor spasticity on modified Ashworth scale of 2 (p Ͻ 0.001). Another Class I study 45 evaluated the need for postoperative pain control in children undergoing adductor muscle lengthening. There was a 74% reduction in postoperative pain (p Ͻ 0.003) and 50% less analgesic use (p Ͻ 0.005) when comparing BoNT-treated children to the placebo group.…”

Hip dislocation in cerebral palsy

“…We found no systematic reviews and only two randomised controlled trials and one evidence report (by the American Academy of Cerebral Palsy and Developmental Medicine). [6][7][8] …”