To investigate the clinical effect of deep brain stimulation (DBS) of the globus pallidus internus (GPi-DBS) for the treatment of primary cervical dystonia.

The clinical data of 14 patients with cervical dystonia treated with GPi-DBS in the Neurosurgery Department of the Second Affiliated Hospital of Air Force Medical University from October 2014 to April 2019 were retrospectively analyzed. The device of DBS was turned on at 1 month after the operation, and all patients were followed up in outpatient clinics at 1, 3, 6 months, 1 year and every year thereafter. Follow-up contents included: observation of hardware-related complications; the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) [including: Torticollis Severity Scale (TSS), Disability Scale (DS) and Pain Scale (PS)] score to assess the improvement of the patient′s symptoms. The calculation formula of improvement rate was: (preoperative score-postoperative score)/preoperative score×100%, of which ≤30% was regarded as mild improvement, >30%-60% as moderate improvement, and >60% was significant improvement.

All 14 patients underwent successful operations, and there were no postoperative complications such as intracranial hemorrhage and infection. A total of 28 electrodes were implanted (on 28 sides), of which the monopolar stimulation mode was applied in 13 electrodes, and the double-monopolar (two cathodes) stimulation mode in 15 electrodes. The follow-up time of 14 patients was 33.7±12.4 months (12-53 months) after the DBS device was turned on. During the follow-up period, 2 patients developed dyskinesia in the lower extremities, and the symptoms were improved by adjusting the stimulation parameters. With the extension of follow-up time, TSS, DS and PS scores all showed a decreasing trend (all P<0.001); torticollis symptoms, disability and pain symptoms were significantly improved 3 months after the device was turned on. At the last follow-up, there was no statistically significant difference in the TSS, DS or PS scores compared with the patients′ conditions at 1 year after the device was turned on (all P>0.05). At the last follow-up, the TSS scores of 14 patients were as follows: 1 case was mildly improved, 6 cases were moderately improved, and 7 cases were significantly improved. In the DS score results, 2 cases were mildly improved, 2 cases were moderately improved, and 10 cases were significantly improved. In the PS results, 14 cases were significantly improved.

GPi-DBS treatment of primary cervical dystonia has fewer complications, significant improvement in torticollis and pain symptoms, and prolonged effect.

Torticollis; Deep brain stimulation; Treatment outcome; Globus pallidus internus