Botulinum Toxin Type A (BoNT-A or Botox ®)
Botulinum toxin is used to block nerve signals to muscles. In muscles, the neuromuscular blockade produced by botulinum results in muscle weakness and reduction of hypertonia or stiffness. Botulinum toxin only affects the muscles that are injected. The effect is temporary and muscle strength returns in 3 – 4 months.
There is plenty of scientific evidence that supports the effectiveness and safety of botulinum toxin to treat spasticity in children with CP. However, at this time the FDA has not approved this indication in children so treatment is prescribed off-label.
- To reduce spasticity in muscles in children with motor disorders: Relaxation of the muscle allows for it to be stretched more effectively. Weakening the muscle with BoNT-A facilitates strengthening of the opposing muscles. In a young child, this combination of stretching and strengthening can delay, limit, or in some cases eliminate the need for orthopedic surgery. Injections are usually given with sedation in the clinic; injections of multiple muscles are done in the operating room. For children with spastic muscles, injections are frequently used in combination with serial casting, which usually begins one or two weeks after the injection.
- To reduce self injurious behavior -- finger biting: Families often must restrain their child so they will not bite their fingers. BoNT-A can be injected into the elbow flexors to relax these muscles so the child is unable to get his fingers in his mouth. This has resulted in a reduction in the use of restraints as well as an increase in fine motor skills development.
- To relax muscles in conjunction with hip surgery to reduce painful postoperative recovery: Injections into a tight or spastic muscle reduces muscle spasms after surgery. Casts and splints are then more tolerable when the muscle is relaxed.