[Treatment of spasticity in cerebral palsy with botulinum toxin]

A review of the pathophysiological and developmental basis, measurement scales and the usefulness of botulinum toxin A injections in selected muscles for the treatment of spasticity in children with cerebral palsy.

Cerebral palsy is the most common cause of spasticity in children. The increase in muscle length is achieved through the addition of sarcomeres in series at the level of the muscle tendinous junction. The regulation of the number of sarcomeres seems to be determined by the lengthening of the muscle. The muscle contracture is a shortening of the length of a muscle as a result of a decrease in the number of sarcomeres. Spasticity and motor function assessment scales used in children with cerebral palsy: a) Modified Ashworth scale for the assessment of spasticity; b) modified Tardieu scale for the assessment of dynamic muscle length; c) muscle spasms frequency scale; d) modified Medical Research Council scale for muscle strength; e) hip adductor muscle tone scale; f) global pain scale with affective facial expression represented in a drawing; g) goniometric measurement of the joint range of movement; h) Palisano gross motor function measure; i) observational video gait analysis scale. Recommended guidelines for dosing the botulinum toxin A: 1. Total maximum dose administered per visit up to 15 U/kg or a total of 400 U; 2. Dose range of large muscles 3 to 6 U/kg per visit; 3. Dose range of small muscles 1 to 3 U/kg per visit; 4. Maximum dose per injection site: 50 U dividing the total planned unit dose/muscle into equal amounts/injection site; 5. Frequency: no more than one injection every 3 months, frequently once every 6 or more months.

Botulinum toxin A injection is a well tolerated, safe and effective procedure in the treatment of children with spastic cerebral palsy.