Dual microvascular decompression for concurrent trigeminal neuralgia and hemifacial spasm

Background: Concurrent trigeminal neuralgia (TN) and hemifacial spasm (HFS) arising from two separate offending vessels, each compressing a distinct cranial nerve, is an uncommon and markedly disabling presentation of neurovascular compression syndrome. Unlike cases in which a single artery accounts for both syndromes, this dual-vessel configuration demands individual identification and decompression of each conflict through a shared operative corridor. Case Description: A 71-year-old man presented with a 13-year history of pharmacologically refractory left V1–V3 TN (Barrow Neurological Institute [BNI] grade IV) and left HFS only partially controlled with quarterly botulinum toxin injections; pre-operative facial motor function was intact (House-Brackmann grade I). Fast Imaging Employing Steady-state Acquisition (FIESTA)-sequence magnetic resonance imaging identified a dolichoectatic basilar artery compressing the left trigeminal nerve and a separate conflict between the left anterior inferior cerebellar artery (AICA) and the facial nerve. Through a left retrosigmoid approach, both conflicts were addressed with independent Teflon pledget interposition secured with fibrin sealant. Lateral spread response (LSR) monitoring served as a continuous electrophysiological marker, with LSR abolition confirming adequate decompression following AICA mobilization. Conclusion: At 6-month follow-up, the patient maintained complete pain freedom (BNI I), sustained HFS resolution, and intact facial function (House-Brackmann I), having discontinued all anticonvulsant therapy and botulinum toxin injections. This case illustrates that dual microvascular decompression via the retrosigmoid approach can safely address concurrent TN and HFS caused by two anatomically distinct vessels, and reinforces intraoperative LSR monitoring as a reliable endpoint for decompression adequacy.