If botulinum toxin fails in the treatment of cervical dystonia, selective peripheral denervation is now accepted as the best surgical option. Despite the very promising results, however, there is still a substantial group of patients who do not benefit from this procedure. Positive response to prior botulinum toxin therapy seems to be a very good predictor of outcome after selective peripheral denervation (P < 0.01). The meaning of the histological findings of the resected nerves is uncertain. Patients with histologically proven pathological nerves do not seem to benefit more than patients with histological normal ones (P < 0.30).