An Anatomic Study On The Relationship Of The Anterior Inferior Cerebellar Artery And Vestibulocochlear Nerve

Objective: Vascular compression of the vestibulocochlear nerve may cause sensorineural hearing loss, tinnitus, constant equilibrium disturbance, recurrent positional vertigo, acquired motion intolerance and other clinical symptoms. Neurovascular compression syndrome of the eighth cranial nerve has not been recognized because its etiological factors, pathophysiology and diagnose criteria are deficient, and the therapeutic efficacy has no evidently identical healing criterion. Howerer, quite a few reports about the successful therapies on the microvascular decompression surgery of the vestibulocochlear nerve have been published. In this study, we observed microsurgerycal anatomy characteristics of the anterior inferior cerebellar artery, the vestibulocochlear (eighth) nerve and related structures and measured magnanimous data through anatomizing forty cerebellopontine angles from twenty cadavers of the Han people. Those data will supply useful anatomic data for the microvascular decompression surgery of the vestibulocochlear nerve in the cerebellopontine angle.Methods: Forty cerebellopontine angles from twenty cadavers of adults provided the material for study, which were fixed with formalin (40 g-L"') for sixmonths. The calvarium and most of the cerebrum were removed. And the cerebeller tentorium was sectioned, providing a thorough view of the cerebellopontine angle. The anterior inferior cerebellar artery and branches related with the VN were then examined with the operating microscope.Results: The incidence of the anterior inferior cerebellar artery, recurrent perforating artery, labyrinthine artery and anterior inferior cerebellar artery loop was 100%. Thirty-two (80%) recurrent perforating arteries passed between the facial (seventh) nerve and the vestibulocochlear nerve. In the thirty-two cerebellopontine angles, some recurrent perforating arteries (87.5%) were located in the external two-third part of the facial nerve and vestibulocochlear nerve in the cerebellopontine angle; some recurrent perforating arteries (87.5%) were located most commonly lateral to the intermediate nerve. Thirty-eight (95%) vestibulocochlear nerves had contact with the anterior inferior cerebellar artery or its branches. Thirty-six (90%) facial nerves had contacted with the anterior inferior cerebellar artery or its branches. In the forty cerebellopontine angles, there were twenty-two (55%) cerebellopontine angles that had two or more branches contacted with the vestibulocochlear nerves and the facial nerves. Among them, twenty (50%) had two or more branches contacted with the vestibulocochlear nerves; twelve (30%) had two or more branches contacted with the facial nerves.Conclusion: These data may be helpful in the microvascular decompression surgery of the vestibulocochlear nerve, analyzing some syndromes and its radiography in the cerebellopontine angle.