Treatment of severe refractory dystonic tremor associated with cervical dystonia by bilateral deep brain stimulation: A case series report

Objectives: The aim of the present study was to present a case series of 3 patients with longstanding, severe, debilitating dystonic head tremor (DT) coexistence with cervical dystonia (CD) treated successfully by bilateral deep brain stimulation (DBS). Pharmacological treatment including benzodiazepines and botulinum toxin injections employed to overactive muscles have failed to adequately control dystonic jerking movements of the head and neck. Patients and methods: All patients were diagnosed with DT who accompanied CD. Two patients underwent bilateral implantation of DBS leads into the posteroventrolateral segment of the globus pallidus internus (GPi). 1 patient received combination of implantation of left lead in the nucleus ventralis intermedius of the thalamus (Vim) and the bilateral implantation of DBS leads in the GPi. All surgeries were uneventful. The formal preoperative objective assessment included Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) and the motor score of Tremor Rating Scale (TRS). The postoperative TWSTRS, TRS assessments were done at 3, 6 months and 12 months postoperatively up to 48 months after surgery. Results: At the 12 months postoperative follow-up visit, the severity, disability and pain scores of TWSTRS were improved by 56 %, 52 % and 38,5 % respectively. The TRS improved by 66 % at 12 months when compared to baseline TRS score. One patient developed seroma over the implanted internal pulse generator and had some wound healing problems which solved without sequel. There were no hardware-related complications over follow-up period. Conclusion: Our experience gathered in 3 patients indicates that bilateral DBS can be an effective treatment for disabling, pharmacological refractory tremulous CD.