Botulinum Toxin in Post-Stroke Spasticity

Botulinum toxin therapy is useful in the treatment of post stroke spasticity as seen in many clinical studies. This therapy is always done in conjunction with the physiotherapists. Successful use of botulinum toxin in spasticity requires careful patient and dose selection. Residual function of the spastic limb and the condition of the agonist and antagonist muscles must be carefully assessed. This is to ensure that the overall condition of the patient will improve by inducing partial or complete paralysis of one or more muscles. It is important that the antagonist muscle(s) must have a) sufficiently powerful functional control, or b) be capable of hypertrophy and strengthening if allowed to perform through the appropriate range of motion, or c) be acceptable in the flaccid state. No fixed joint deformity should be present. It is important to check that weakening the spastic limb(s) will not further compromise residual function (including gait). The rationale for the use of botulinum toxin in spasticity is that a velocity-dependant increase in the stretch reflex response in a spastic antagonist muscle may interfere with normal movement in an agonist muscle. However, spasticity may be beneficial in certain situations, eg. leg extension in spasticity may act as a brace in some patients and assist gait. Generally, the side effects associated with botulinum toxin are temporary and well tolerated. The advantages of botulinum toxin are avoidance of anaesthetics, high patient acceptance and persistence of benefit for months. It also facilitates rehabilitation goals, i.e. increased range of motion, ease of hygiene and positioning, and improves quality of life. Its main disadvantage is its high cost.