Neurosurgical treatment for writer's cramp.

BACKGROUND

Writer's cramp is a type of focal dystonia due to dysfunction of the pallido-thalamo-cortical circuit. The symptom is refractory to most conservative treatment, though botulinum toxin injection is generally used for symptomatic relief. As a surgical treatment of dystonia we performed stereotactic nucleus ventrooralis (Vo) thalamotomy for dystonic cramp of the hand.

METHOD: Eight patients (5 men, 3 women, age 26-40 yrs, mean 32.1 yrs) with medically intractable task-specific focal dystonia of the hand underwent Vo thalamotomy. Stereotactic target was chosen at the junction of the anterior and posterior Vo nuclei.

FINDINGS: The mean duration of the symptom ranged from 3 to 6 years (mean, 4.0 yrs). All patients had complained of difficulty in writing. Six patients were professional workers, such as comic artist, guitarist, and barber, and, because of the dystonic symptoms at their professional work, they had stopped pursuing their profession. All patients showed immediate postoperative disappearance of dystonic symptoms, and the effect was sustained during the follow up period (3-29 months, mean 13.1 mo) except in one case. One patient showed partial recurrence of the symptom and underwent second thalamotomy 5 months after the initial surgery with satisfactory results. The score of the writer's cramp rating scale significantly (p < 0.001) decreased after Vo thalamotomy. There was no permanent operative complication. There was no mortality or permanent morbidity.

INTERPRETATION: Although a longer follow-up is needed, stereotactic Vo thalamotomy is a useful and safe therapeutic option for writer's cramp.