Surgical Interventions for Task-specific Dystonia (Writer's Dystonia)

Writer's cramp is a focal dystonia producing abnormal postures during selective motor activities. Thalamotomy or globus pallidus internus deep brain stimulation (GPi DBS) has been used as a surgical treatment in patients not responding to medical treatment.

Eight patients (all men, age 16-47 years) with refractory focal hand dystonia underwent either ventrooralis (Vo) thalamotomy (seven patients) or GPi DBS (one patient) using stereotactic techniques. Preoperative video recordings, Writing movment score for dystonic posture and latency of dystonia (WMS), and symptom severity scores (SSSs) were evaluated at baseline and latest follow-up ranging from 1 to 4 years.

All patients had difficulty in performing their most common tasks. The duration of symptoms ranged from 6 months to 12 years. All patients obtained immediate postoperative relief from the dystonic symptoms, and the effect was sustained during the follow-up period. The WMS (range 0-28) improved from a mean of 14.5 before surgery to 2, whereas the SSS (maximum 43 and minimum 10) improved from a mean of 15.3 before surgery to 2 at the last follow-up. There were no surgical complications, morbidity, or mortality.

Vo thalamotomy or GPi DBS offers successful symptom relief in patients with task-specific dystonia.