title: The effect of botulinum toxin A on gastrocnemius length: magnitude and duration of response.
abstract: Thirty-nine ambulant children (22 with hemiplegia, 17 with diplegia) with spastic cerebral palsy receiving isolated gastrocnemius muscle injection with botulinum toxin A were studied prospectively. The children had a mean age of 6 years (range 3 to 13 years). Measurement of gastrocnemius muscle length was used to estimate the dynamic component of each child's spasticity and to quantify the response. There was a strong correlation between the dynamic component of spasticity before injection and the corresponding magnitude of the response after injection. Children undergoing repeated injections showed similar correlations. A strong correlation was found between the duration of response and the dynamic component. Children with hemiplegia showed twice the duration for a given dynamic component compared with those with diplegia when injected with the same total dose per unit body weight. Long-term lengthening did not occur for the cohort, although some patients showed a response at a 12-month follow-up. By delaying shortening, the injections may have a role in delaying the need for surgery. Injections were well tolerated with few side effects.
authors.affiliation: The Gait Analysis Laboratory, Musgrave Park Hospital, Belfast, N Ireland.
authors.forename: N W
authors.initials: NW
authors.lastname: Eames
authors.forename: R
authors.initials: R
authors.lastname: Baker
authors.forename: N
authors.initials: N
authors.lastname: Hill
authors.forename: K
authors.initials: K
authors.lastname: Graham
authors.forename: T
authors.initials: T
authors.lastname: Taylor
authors.forename: A
authors.initials: A
authors.lastname: Cosgrove
mesh_terms: D000293:Adolescent; D019274:Botulinum Toxins, Type A / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006429:Hemiplegia / Q000188:drug therapy / Q000503:physiopathology; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects*; D018482:Muscle, Skeletal / Q000187:drug effects*; D009465:Neuromuscular Agents / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use*; D010243:Paralysis / Q000188:drug therapy* / Q000503:physiopathology*; D011446:Prospective Studies; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A