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

Background and objectives: 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.

Methods: 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.

Results: 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).

Conclusion: 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.