A randomised, double-blind, dose-ranging study to evaluate efficacy and safety of three doses of botulinum toxin type A (Botox) for the treatment of spastic foot

Abstract

Botulinum toxin A (BTX) injections have been used successfully in the treatment of post-stroke foot spasticity, but the optimal dose-response relationship for selected muscles has yet to be established. The aim of this study was to outline beneficial and unwanted effects of three different doses of BTX in the treatment of spastic foot. In this randomised, double-blind, dose-ranging study, 45 spastic feet were randomly allocated to one of three groups, each of which was treated with a different dosage of BTX. The doses were decided on the basis of suggestions in the literature. Outcome measures (Modified Ashworth Scale, Medical Research Council Scale, gait assessment, presence of Achilles tendon clonus, Visual Analogue Scales for Gait Function and Pain, Adverse Effects scale) were applied at baseline, 4 weeks and 4 months after treatment. All the groups showed significant scales scores improvements after treatment with BTX. Group II (mean BTX total dose: 322 U) and Group III (mean BTX total dose: 540 U) showed a greater and more prolonged response than Group I (mean BTX total dose: 167 U). Group III showed the highest rate of adverse effects 4 weeks post-treatment. BTX injections constitute a useful and safe method of improving post-stroke foot spasticity, associated pain, gait speed and function. In particular, the medium BTX dosages (320 UI spread over 2-5 muscles) were found to be both safe and effective in producing long-lasting improvement of spastic foot dysfunction.

Effect of Simultaneous Botulinum Toxin Injections Into Several Muscles on Impairment, Activity, Participation, and Quality of Life Among Stroke Patients Presenting With a Stiff Knee Gait

“…8,9 The gait analysis demonstrates that BoNT A injection improves knee flexion during the swing phase: disappearance of the double-bump shape and increase of Ϸ5°in knee flexion amplitude. Stoquart et al 7 found similar results after 200-U BoNT A injection in the RF, and Sung et al 5 found similar results after phenol injection of the RF motor branch.…”

“…Dose-related BoNT A injection efficacy was clearly demonstrated by a placebo-controlled randomized controlled trial on muscle tone, commonly assessed by the Ashworth scale; 8,9 specifically, the effects of BoNT A injection have been shown only to improve impairments. The impairment reduction may lead to a reduced burden of care, eg, an increase in the passive range of motion facilitating dressing.…”

Poststroke Spasticity Management

“…28,[38][39][40][41] It has been suggested that proper choice of muscles and individualized doses of BoNT type A can improve function in selected poststroke patients. 42 Advantages of BoNT over oral medications is target specificity (ie, exerting significant changes only in injected muscles) and better adverse event profile.…”

Comparison of Systemic Toxicity between Botulinum Toxin Subtypes A1 and A2 in Mice and Rats

“…These toxin products have an upper dosage limit, and their adverse events have become serious issues, speculated as after-effects of diffusion after high-dose administration [12][13][14][15]. Therefore, a preparation with greater therapeutic efficacy at lower dosages, and showing less diffusion in the body than existing drugs, has been sought.…”