Microvascular Decompression Surgery for Hemifacial Spasm: The Lateral Suboccipital Infrafloccular Approach

Abstract

We describe the approaches and techniques for microvascular decompression (MVD) for hemifacial spasm (HFS), focusing particularly on the lateral suboccipital infrafloccular approach. The lateral suboccipital infrafloccular approach for HFS differs completely from the approach for trigeminal neuralgia, although both approaches are termed as lateral suboccipital approach (LSA) [4, 8–10, 13–15]. The root exit zone (REZ) of cranial nerve (CN) VII or a nearby area is usually responsible for vascular compression-related HFS; therefore, we recommend the lateral suboccipital infrafloccular approach, in which REZ of CN VII is approached through the space between the origin of CN IX and the flocculus and choroid plexus protruding the foramen of Luschka from the inferior side [4, 7, 10, 13–15]. This approach can be used not only for MVD for HFS but also for other surgeries around the supraolivary fossette such as acoustic schwannoma surgery or pontomedullary tumor surgery.