Cervical dystonia (CD), also known as spasmodic torticollis, is the most common of the focal dystonias. Muscle hypertrophy is present in nearly all patients, and neck pain is associated with CD in about 80% of patients. Remissions can occur in about 20% of patients, though most last under a year.
Medical therapies have not generally worked well for patients with CD, and are typically associated with many side effects. Botulinum toxin (BT), which causes fewer side effects, has been considered the treatment of choice. Beyond medical therapy, various surgeries for CD have been performed for many decades. Of surgical treatments now in use, selective peripheral denervation is the most common.
In CD, botulinum toxin type A (BT-A) targets pain, dystonic posturing, limited range of motion, and tremor. BT type B (BT-B) is a serotype of BT that is ontogenetically distinct from the type A toxin. There have been three randomized, multicenter, double-blind, placebo-controlled trials of BT-B. It appears that BT-B is a safe and effective treatment for patients with CD who are responsive or resistant to BT-A.