Symptomatic and functional outcome of surgical treatment of cervical dystonia

Previous studies of surgical treatment for cervical dystonia have reported highly variable rates of postoperative symptomatic benefit and morbidity. Little is known about functional improvement and long term results. This study evaluates the symptomatic and functional outcome of surgical treatment of cervical dystonia in a consecutive series of 46 patients.

The most affected muscles were selected for denervation after clinical examination and confirmation by four channel EMG studies. Surgical treatment, aiming at selective elimination of pathological activity while preserving normal motor function and avoiding side effects, was achieved by using a broad scope of techniques including intradural denervation, extradural denervation, and myotomy. Rather than carrying out standard operations, the treatment was tailored to the needs of the patient according to the individual pattern of dystonic activity. Long term benefit was assessed with a global outcome score, and a modified Toronto western spasmodic torticollis rating scale (TWSTRS) in those 34 patients who were available for a recent follow up evaluation.

The 46 patients underwent a total of 70 procedures with intradural approaches in 33 instances, extradural approaches in 21, and muscle sections (singly or combined) in 22 instances. Transient mild postoperative side effects occurred in 10% of the procedures. The mean duration of long term follow up was 6.5 years. The global outcome was rated as excellent in nine patients (21%), as marked in 12 (27%), as moderate in nine (21%), as mild in nine (21%), and as no improvement in five (11%). A persistent side effect consisting of mild difficulty with balance was noted in one case. There were highly significant changes of the preoperative and postoperative mean values for almost all TWSTRS subscores for severity of cervical dystonia, functional disability, and pain. Patients with excellent outcome underwent a higher number of surgical procedures on average than those patients who achieved no benefit.

Surgical treatment tailored to the specific pattern of dystonic activity in the individual patient is a valuable alternative in the long term management of cervical dystonia.