Hemifacial spasm secondary to Chiari malformation type I: Systematic review with case illustration.

Hemifacial spasm (HFS) can be associated with Chiari malformation type I (CM1), but the treatment paradigm for these concurrent conditions has not been well-defined. We sought demographical differences between patients with HFS with and without CM1 and explored optimal surgical treatments for these patients. A systematic review of peer-reviewed literature identified 8 studies with 51 patients with CM1 and HFS. A patient from the authors' institution is presented as a case illustration. Of the 51 patients, the average age was 39.4 years, 63% (32/51) were female, 73% (37/51) underwent microvascular decompression (MVD) as a primary intervention, and 16% (8/51) underwent suboccipital decompression (SOD). After primary MVD, 83.7% (31/37) had complete resolution of their symptoms and 10.8% (4/37) had either recurrent CM1 symptoms or new-onset CM1 symptoms. Three (8.1%) required reoperation with suboccipital decompression to address new CM1-related symptoms. All patients who underwent SOD first had complete or near-complete resolution of symptoms. In 3 patients (37.5%) with near-complete resolution, the residual symptoms had insignificant impact on their quality of life. These data suggest that concomitant CM1 should be among the differential diagnosis in younger patients who present with HFS, particularly those who are female or who present with history suggesting tussive headaches. For patients who present with HFS and headache with CM1, SOD instead of MVD may be the preferred surgery to address concurrent symptoms. In patients with HFS and CM1 without headache, optimal treatment is less clear, but SOD as initial surgery may obviate the need for future reoperation.