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Objective: To evaluate botulinum toxin treatment of hyperactive upper esophageal sphincter after first-time brainstem stroke. Design: A retrospective study. Subjects: Twelve patients with long standing dysphagia after brainstem vascular injury admitted to the rehabilitation department of a medical centre. Methods: All patients underwent clinical examination, videofluoroscopic study of swallowing and electromyography. Botulinum toxin was injected percutaneously under electromyographic guide. Outcomes were measured after two weeks and through a long follow up programme, which ranged from two to ten years. Results: A total of 75% of patients (9 of 12) had favourable outcomes. Two patients showed long lasting functional benefits after only one botulinum toxin injection, while seven patients required further treatments to maintain an adequate oral intake. In seven cases it was possible to remove percutaneous endoscopic gastrostomy. No relevant complications were observed. Conclusion: Botulinum toxin can improve severe dysphagia with elective hyperactivity of the upper esophageal sphincter in patients with or without unilateral paresis of the inferior constrictor muscle and in absence of a nuclear involvement of the IXth and Xth cranial nerves. The outcome could be unsatisfactory in the cases of oral phase involvement, bilateral lesion of the inferior constrictor muscle and when there is velopharyngeal insufficiency.

Objective To compare the effect of electrical stimulation applied before and after botulinum toxin injection. Subjects Eight healthy subjects. Methods Both extensor digitorum brevis muscles were injected with low fixed doses of botulinum toxin. Subjects received a 20-min session of electrical stimulation before botulinum toxin injection for the right foot and after the injection for the left foot. Percentage changes in compound muscle action potential amplitude were calculated at different intervals over a 60-day period. Results A reduction in compound muscle action potential percentage was measured at every time-point, both for the muscles stimulated before injection of botulinum toxin and for those stimulated after injection. The compound muscle action potential percentage was always lower on the side stimulated after injection of botulinum toxin. A reduction in compound muscle action potential percentage was measured on the 7th and 15th days in all extensor digitorum brevis muscles examined. On the 15th day the compound muscle action potential percentage was 38.8 (right foot) vs 24.1 (left foot) (p=0.0117). A slow recovery was observed after this period. Conclusion Electrical nerve stimulation enhances the effect of botulinum toxin to a greater extent if applied after injection rather than before. The short stimulation time used in our study gave similar results to those seen in previous research using longer application times.