Bilateral deep brain stimulation for cervical dystonia: long-term outcome in a series of 10 patients.
BACKGROUND
Bilateral globus pallidus internus (GPi) deep brain stimulation (DBS) was shown to be effective in cervical dystonia refractory to medical treatment in several small short-term and 1 long-term follow-up series. Optimal stimulation parameters and their repercussions on the cost/benefit ratio still need to be established.


OBJECTIVE
To report our long-term outcome with bilateral GPi deep brain stimulation in cervical dystonia.


METHODS
The Toronto Western Spasmodic Torticollis Rating Scale was evaluated in 10 consecutive patients preoperatively and at last follow-up. The relationship of improvement in postural severity and pain was analyzed and stimulation parameters noted and compared with those in a similar series in the literature.


RESULTS
The mean (standard deviation) follow-up was 37.6 (16.9) months. Improvement in the total Toronto Western Spasmodic Torticollis Rating Scale score as evaluated at latest follow-up was 68.1% (95% confidence interval: 51.5-84.6). In 4 patients, there was dissociation between posture severity and pain improvement. Prevalently bipolar stimulation settings and high pulse widths and amplitudes led to excellent results at the expense of battery life.


CONCLUSIONS
Improvement in all 3 subscale scores of the Toronto Western Spasmodic Torticollis Rating Scale with bilateral GPi deep brain stimulation seems to be the rule. Refinement of stimulation parameters might have a significant impact on the cost/benefit ratio of the treatment. The dissociation of improvement in posture severity and pain provides tangible evidence of the complex nature of cervical dystonia and offers interesting insight into the complex functional organization of the GPi.
Cacciola
Francesco
F
Walton Centre for Neurology and Neurosurgery, Liverpool, UK. francesco.cacciola@gmail.com
Farah
Jibril Osman
JO
Eldridge
Paul R
PR
Byrne
Patricia
P
Varma
Telekath K
TK
D000328:Adult; D046690:Deep Brain Stimulation / Q000379:methods*; D005260:Female; D005917:Globus Pallidus / Q000502:physiology*; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D013997:Time Factors; D014103:Torticollis / Q000628:therapy*; D016896:Treatment Outcome