Botulinum toxin-A injections for spastic toe clawing

Abstract

Spastic toe clawing describes extension at the metatarsophalangeal joints of the feet, flexion at the proximal interphalangeal joints and flexion at the distal interphalangeal joints that results from upper motor neuron lesions, such as stroke, intracranial hemorrhage, cervical myelopathy and brain tumors. Even though toe clawing is often asymptomatic, it can be painful. Previous studies have described the efficacy of injections of botulinum toxin type-A (BTX-A) to the long flexors of the toes, but this is often unsatisfactory as high dosages (up to 175 units) have been required, and patients often report significant residual toe clawing. We performed an open label, prospective study to assess the efficacy of BTX-A injections, targeting the long and short flexors of the toes, performed with electrical (motor point) stimulation under electromyographic guidance. Outcome measures, which included timed walking over 20 m, objective assessment of toe clawing (modified Ashworth scale and a visual analog scale rating) and patient assessment of functional disability, were assessed before injections and at six-weeks' follow-up. Seven patients (five male and two female) of mean age 51 (range 38-70) were recruited. Four had spasticity from underlying intracranial hemorrhage, the remaining three from cerebral infarct, astrocytoma and post-traumatic cervical myelopathy. The total dose of BTX-A injected for toe clawing ranged from 40 to 90 units. Improvements were observed in all outcome measures except timed walking. Injecting BTX-A to the long and short flexors of the toes, with electrical stimulation under electromyographic guidance, is well tolerated and efficacious in the treatment of toe clawing from spasticity, allowing for lower dosages to be used. © 2005 Elsevier Ltd. All rights reserved.