The Role of Neurovascular Compression and Hypertension in Hemifacial Spasm

Abstract

Background: Hemifacial spasm (HFS) is characterized by involuntary spasms in the muscles innervated by the facial nerve. The most important cause of HFS is vascular compression of the seventh cranial nerve. No common consensus about the vascular compression of the medulla oblongata and seventh cranial nerve cause not only HFS but also hypertension (HT). On the other hand, there is another theory, which suggests HT may change vascular structure and cause HFS. For that reason, cause and result relationship in HFS are still conflicting. Objective: We aimed to investigate demographic and clinical features of HFS and risk factors for HFS, particularly hypertension. We also performed cranial magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) in patients with HFS for detecting neurovascular compression (NVC). Material and Methods: 40 patients who are clinicaliy diagnosed HFS and 40 patients without HFS with same age and gender were included into study. Medical history, physical and neurological examination, cranial MRI and MRA were done to ali patients. Results: We found 22 (55%) cases in HFS group and 3 (7,5%) cases in control group were detected NVC on root entry zone of facial nerve (p<0.05). The vascular structures causing neurovascular com pression were vertebral artery in 13 (59%), anterior inferior cerebellar artery in 5 (22.8%), posterior inferior cerebellar artery in 3 ( 13.7%) and basilar artery in 1 (4.5%). Hypertension was diagnosed in 21 (52.5%) cases of HFS group, and in 16 (40%) cases of control group. There was no statistically significant difference between two groups regarding hypertension (p>0.05). HFS was inspected on right side in 10 (25%) patients and on left side in 30 (75%) patients. Left HFS is more common but not statistically significant than right. NVC was detected in 18 (60%) patients on left side, 4 (40%) patients on right side. NVC was also seen more frequently but not statistically significant on left side (p>0.05). On the other hand, there was no statistically significant difference between right-left side HFS and HT- without HT patients. Conclusion: We found NVC on root entry zone of facial nerve in 55 %of HFS patients. HFS and NVC were seen more frequently on left side than right. This study suggests that the NVC can be diagnosed by cranial MRI and MRA and HT is not a risk factor alone for HFS.