[Trigeminal neuralgia and hemifacial spasm associated with vertebrobasilar artery tortuosity].

Background: The tortuous vertebrobasilar artery (TVBA) often causes neurovascular conflicts in patients with trigeminal neuralgia (TN) and hemifacial spasm (HFS). Implementation of microvascular decompression (MVD) in these circumstances is hindered due to stiffness of the enlarged and dilated arteries and is often accompanied by poor outcomes. The surgical strategy in cases of trigeminal neuralgia and hemifacial spasm associated with the TVBA should be clarified in order to achieve good outcomes.
Material and Methods: MVD was performed in 268 TN patients and 71 HFS patients. The TVBA as a compressing vessel was identified in 30 cases (11 cases of TN, 18 cases of HFS, and 1 patient with painful tic convulsif). All patients underwent MVD and a retrospective analysis of clinical outcomes.
Results: Compression caused by the vertebral artery was found in all HFS patients and 4 TN patients, and compression caused by the basilar artery was observed in 7 TN cases. Additional compression of the cranial nerve root entry/exit zone by cerebellar vessels was observed in 21 cases. The TVBA was mobilized by dissection of arachnoid adhesions between the vessel and the brainstem and retracted laterally. Then, the TVBA was retracted from the brainstem to the caudorostral direction. These manipulations resulted is "spontaneous" decompression of the cranial nerves without placing prostheses between the artery and the nerve root entry/exit zone. In all cases (except two), the displaced TVBA was fixed between the enlarged artery and brainstem using pieces of the patient's muscle and adipose tissues, followed by application of fibrin glue. A cylindrical silicone prosthesis was used in 1 case. In another case, the TVBA was retracted using a fascial loop fixed to the dura mater of the petrous pyramid by means of a suture. After application of MVD, TN and HFS symptoms completely regressed. There were several transient complications and 2 cases of permanent hearing loss. No clinical symptom recurrence was observed.
Conclusion: MVD is the most effective surgical treatment of TN and HFS caused by the TVBA. The TVBA should be retracted from the brainstem without placing prostheses in the nerve root entry/exit zone.