Objective:

Report the effectiveness of bilateral deep brain stimulation (DBS) of the globus pallidus internus (GPi) for management of anterocollis in patients with isolated dystonia. 

Background:

Anterocollis is one of the most difficult forms of cervical dystonia (CD) to treat. Botulinum toxin therapy (BoNT) can be technically challenging and is accompanied by high rates of side effects including neck weakness and dysphagia. GPi DBS is an effective long-term treatment for patients with CD. However, outcomes in patients with anterocollis as the primary postural abnormality have been inconsistent and scarce.

Design/Methods:

We retrospectively reviewed clinical characteristics and outcomes of DBS therapy in patients with anterocollis as the primary feature of their dystonia at our large academic institution.

Results:

Four patients managed with GPi DBS for refractory symptoms with prominent anterocollis were identified (three females). Mean age at DBS implantation was 67 years. Mean follow-up was 4 years (range 2-9 years). All patients had isolated dystonia with moderate to severe anterocollis as primary feature prior to DBS, with mean total Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) score of 45.8 (SD=8.5) and severity score of 21 (SD=3.2). Mean TWSTRS total score decreased to 6.5 points (SD=4.7), and severity score decreased to 5.5 points (SD=5) at the most recent follow-up evaluation. All patients had improvement in TWSTRS by the 12-month programming visit that exceeded the minimal clinically important change; this benefit was sustained for the duration of follow-up.  All patients initially received BoNT for anterocollis prior to DBS; three stopped due to lack of efficacy and one stopped after DBS. Final effective DBS stimulation parameters were variable, but a common theme of high pulse width ranging from 110-180µs was noted. 

Conclusions:

Bilateral GPi DBS therapy can be an effective option for patients with anterocollis in isolated dystonia. High pulse widths (110-180µs) may be beneficial for optimal symptom control.