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.

The role of botulinum toxin injections in the management of muscle overactivity of the lower limb

“…The same group showed that BT injections into hamstrings and gastrocnemius in children with cerebral palsy facilitated increased length of these muscles [131,132]. Observations that BT injection may delay tendon lengthening surgery in cerebral palsy are consistent with these results [105,133,134].…”

Long-term effect of repeated injections of botulinum toxin in children with cerebral palsy: A prospective study

“…Injections of BTX-A repeated every three months have proven to be safe and effective in chronic management of focal muscle spasticity in children with equinus gait [9]. A strong correlation was found between duration of response and the dynamic component in children undergoing repeated gastrocnemius muscle injections [10]. Another clinical trial [11] described significant improvements of the gait parameters after the first and second injections in children with spastic equinus foot.…”

A comparison of gastrocnemius muscle–tendon unit length during gait using anatomic, cadaveric and MRI models

“…Orendurff et al [4] compared the gastrocnemius MTU length of cerebral palsy patients, who walked in equinus before and after the patients underwent surgical tendo Achilles lengthenings. Eames et al [7] palsy to determine a correlation between the dynamic component of muscle shortening before injection and the magnitude of the response (muscle length change).…”

“…Current interventions, such as surgery [1,[4][5][6] and Botox injections [7] are designed to alter muscle length, normalize joint motion and improve function. Orendurff et al [4] compared the gastrocnemius MTU length of cerebral palsy patients, who walked in equinus before and after the patients underwent surgical tendo Achilles lengthenings.…”