Description: Botulinum toxin A (Botox®) is a purified form of the toxin that causes the food poisoning botulism. When injected directly into a spastic muscle, botulinum toxin stops some of the signal getting from the nerve into the muscle. This weakens the muscle and decreases the spasticity. Botulinum toxin does not spread beyond the muscle injected and does not change the feeling in the area injected.
Who may benefit: Botulinum toxin works best when spasticity is a problem in only a few muscles. Examples of its use include injection into the calf to decrease toe walking, the back of the thigh to decrease knee flexion and scissoring (crossing legs) and injection into the muscles of the arm to decrease elbow flexion.
How it is done: Injections are done in an out-patient clinic. The drug takes a while to work; people usually begin to see results in two to three days. The maximum effect is seen in six to eight weeks. Injections are often followed by casting for two to four weeks. This is done to take advantage of the drug’s effect on the muscle and to get a maximum stretching effect. The drug stops working after four to six month and needs to be repeated in many patients.