Comparison of Pallidal and Subthalamic Stimulation for Cranial Cervical Dystonia: A 4-Year Follow-up Study

Deep brain stimulation (DBS) targeting the globus pallidus internus (GPi) or subthalamic nucleus (STN) is well established for treatment of craniocervical dystonia (CCD). This study aims to compare the long-term outcomes of GPi-DBS and STN-DBS for CCD and identify potential prognostic factors. This retrospective study analyzed 78 consecutive patients with CCD treated with bilateral DBS at a single medical center, comprising 2 nonrandomized cohorts: GPi-DBS (n = 38) and STN-DBS (n = 40). Motor and nonmotor symptoms were assessed using standardized rating scales at baseline, 6 months, and 1, 2, 3, and 4 years after surgery. Multiple linear and logistic regression analyses were performed to identify potential prognostic factors for long-term outcomes. At 6 months, the STN group showed greater improvement in motor symptoms compared with the GPi group (50.48% [95% CI, 40.12%-60.84%] vs 34.92% [95% CI, 24.84%-45.00%], P = .046), although this difference was not significant after adjusting for multiple comparisons (threshold P < .01). No significant differences in motor symptom improvement were observed between the 2 groups at later follow-up points. Among all Burke-Fahn-Marsden dystonia rating scale movement subscale scores, the STN group showed greater improvement in the eye subscore at 6 months, 2 years, 3 years, and 4 years, but these differences were also not significant after adjusting for multiple comparisons. Both groups demonstrated significant improvements in mood and quality of life at the last follow-up. Cognitive functions remained stable. Multiple regression analysis revealed a negative correlation between disease duration and motor improvement (standardized β = -.023, 95% CI, -0.044% to -0.003%, P = .028). Both GPi- and STN-DBS can effectively improve motor symptoms and quality of life of patients with CCD, with comparable long-term efficacy. Early intervention is critical, with disease duration being an important prognostic factor for long-term motor improvement.