Comparison of two injection techniques using botulinum toxin in spastic hemiplegia

This study sought to test the hypothesis that injections of botulinum toxin type A (BTX-A) at the mid belly of the gastrocnemius muscle in spastic hemiplegic adults produce superior clinical results to proximal injections directed toward the muscular origin. We designed a randomized, double-blind, placebo-controlled intervention study at a university tertiary care setting. Seventeen subjects with chronic spastic hemiplegic gait were enrolled from a volunteer community sample; time range from acute neurologic insult was 0.75 to 31 yr; age range was 19 to 71 yr; gender consisted of 11 men and 4 women; diagnoses were 12 patients with stroke, 2 with traumatic brain injuries, and 1 with a brain tumor. Two subjects were withdrawn from the study because of (1) acute vascular occlusion before intervention and (2) noncompliance with follow-up visits. After baseline measurements, subjects were injected with 50 units of BTX-A (volume, 0.5 cc) into the medial or lateral gastrocnemius: (1) proximally at one site near the muscular origin; (2) distally at three sites along the mid belly. We measured outcome using the Fugl-Meyer score, Ashworth scale, ankle range of motion, and a timed 50-ft fastest walk. No outcome measures showed a significant effect attributable to site of injections. Confounding variables included physical therapy and varying duration of illness in the study cohort. We conclude that the results failed to support the hypothesis that BTX-A injections at the mid belly of the gastrocnemius produced superior functional improvements to injections located near the muscular origin using localization techniques described. Additional research comparing more precise localization methods for BTX-A injections might further establish the importance of electromyographic guidance using BTX-A in management of spasticity.