Patients with
thoracic outlet syndrome (TOS) who improve temporarily after
anesthetic blockade of the anterior scalene muscles have been shown to improve after ultimate
surgical decompressions at the interscalene triangle.
Anesthetic blockade of the scalene muscles, even with the addition of
steroids, however, rarely produces any prolonged relief as patients are awaiting definitive surgery. The present study was undertaken to determine if more effective and prolonged relief might be obtained with electrophysiologically and fluoroscopically guided selective injection of the scalene muscles with
botulinum toxin, which has been used in the past for treating conditions associated with
spasm of cervical muscles. In 14 of 22 patients (64%) with a clinical diagnosis of TOS, there was more than a 50% reduction of symptoms measured by a 101-point scale for at least 1 month after botulinum
chemodenervation of the scalene muscles. Only 4 of the 22 patients (18%) had a 50% reduction of symptoms for at least 1 month after injection with
lidocaine and
steroids. In no patient were the results of
lidocaine and
steroid injection superior to botulinum
chemodenervation.
Chemodenervation had a mean duration of effect of 88 days. No significant side effects were encountered with botulinum
chemodenervation except for mild transient
dysphagia in two cases. These results appear to demonstrate that botulinum
chemodenervation of the scalene muscles may be helpful in alleviating symptoms in patients with TOS awaiting definitive
surgical decompression.