Outcomes of pallidal deep brain stimulation for treating pure blepharospasm

Objective: Blepharospasm (BSP) is a disease in which the closure rate of the bilateral eyelids increases, mainly due to involuntary contraction of the orbicularis oculi, procerus, and corrugator muscles. The objective of this study was to report postoperative outcomes after deep brain stimulation (DBS) in 10 cases of pure BSP after at least 12 months of follow-up.Methods: Ten patients with pure BSP who underwent bilateral globus pallidus interna (GPi) DBS at The Catholic University of Korea, Incheon St. Mary’s Hospital, between 2019 and 2021 were included. The Burke-Fahn-Marsden dystonia rating scale (BFMDRS), Blepharospasm Disability Index, and Jankovic Rating Scale were used for analysis before surgery, at 6 months of follow-up as short-term outcomes, and at follow-up over 1 year (12–37 months) as long-term results. Results: The median age of patients at surgery was 56.5 years (interquartile range [IQR], 50.5–65.8 years) and the median length of time from disease onset to the time of surgery was 58.0 months (IQR, 46.8–64.3 months). The median postoperative follow-up period was 22.5 months (IQR, 15.3–29.0 months). The median BFMDRS movement subscale scores at the three time points (preoperative baseline, 6 months, and over 1 year of follow-up) were 7.0 (IQR, 6.0–8.0), 4.5 (IQR, 3.9–6.0; 35.7% improvement, p<0.001), and 3.8 (IQR, 2.8–5.3; 45.7% improvement, p=0.002), respectively.Conclusion: Bilateral GPi DBS for pure BSP can be effective if conservative treatment options fail. Its benefit is not only observed in the short term, but is also maintained during long-term follow-up.