Botulinum toxin injections have been found to be effective in the treatment of spasticity associated with cerebral palsy when used as one element of a multidisciplinary physical therapy program.
Botulinum toxin A is a potent agent for inhibiting transmission between nerve cells and the muscles they innervate. As the name indicates, taken in sufficient amounts (usually by eating spoiled canned products), it can cause serious systemic effects including widespread muscle weakness and paralysis. Injected in small amounts into spastic or overactive muscles, it can reduce muscle pain and improve function. First used in the early 1980 s for the treatment of imbalance in eye muscles, it is now used for an increasing number of neuro-muscular abnormalities including cerebral palsy. Botox is the brand name of the injectable product.
Morton and his associates (1) have reviewed the available evidence for using Botox in children and adults with cerebral palsy. They cite well conducted experiments to show that botulinum toxin is better than placebo in management of spastic calf muscles improving gait. Injection into appropriate thigh muscles reduces hip pain. They cite many studies demonstrating the effectiveness of other specific injections for hemiplegic, diplegic, and quadriplegic children. Botox has been less effective in dealing with arm movement in part because it weakens the patient s grip.
The effects are transient, usually wearing off in 3-4 months and often requiring re-injection. It should be used in concert with a multidisciplinary team and carefully defined goals. In the authors view, it works best in younger children in combination with stretching exercises, gait training, and often splinting. They have treated children with Botox for more than seven years and believe it to be safe in the amounts recommended by the manufacturer.
In the United States, the Food and Drug Administration (FDA) has approved Botox only for strabismus (eye squint), blepherospasm (forced eye blinking, and dystonia (muscle spasms) of the neck. However, it is widely used for other conditions both in the United States and elsewhere. Such “off use” of medication is a widespread practice. When Botox is offered, parents should be convinced that the physician administering the agent is trained and experienced in its use in children and that it has been adequately studied for the specific indication for which it is being offered. Participation in future studies should be encouraged.
Morton, R.E., Hankinson, J., Nicholson, J., Botulinum toxin for cerebral palsy; where are we now?
Archives of Diseases of Childhood, 2004 Dec; 89(12):1133-7.