Microvascular Compression of the Vestibulocochlear Nerve

Abstract

Keypoints Microvascular contacts or compressions of the ves-tibulocochlear nerve can result in tinnitus. 2. For nonpulsatile tinnitus, the contact is most often at the central nervous system segment. 3. For pulsatile tinnitus and typewriter tinnitus, the contact is at the peripheral nervous system segment. The tinnitus is unilateral and characterized by intermittent paroxysms of tinnitus. 4. Associated symptoms are correlated with related contacts/compressions of nearby nerves and include overt or cryptogenic hemifacial spasms, geniculate neuralgia, optokinetically induced short bouts of disabling positional vertigo, and tinnitus frequencyspecific hearing loss. 5. Auditory brainstem responses (ABRs) correlate with disease progress and clinical symptoms and can be used diagnostically.(a) Tinnitus is causally related to a decrease in amplitude of peak II in the ipsilaterally elicited ABR. (b) Tinnitus frequency-specific hearing loss is causally related to prolongation of the ipsilateral interpeak latency (IPL) I-III. (c) Prolongation of contralateral IPL III-V occursand is a sign of slowed signal transmission in the brainstem. 6. Magnetic resonance imaging sequences with constructive interference in steady state can visualize most vascular contacts/compressions of the auditory nerve. 7. Microvascular decompression should be performed before irreversible nerve damage is induced; clinically, the procedure should be performed before 4-5 years. Keywords

Tinnitus

“…Surgery to decompress these neurovascular confl icts could therefore off er a resolution of the symptoms in these cases; however, the evidence so far is confl icting. Although some researchers have reported positive results, 87 these are based on small numbers of patients. This type of surgery is best thought of as a preliminary experimental technique.…”

Tinnitus risk factors and treatment in adolescents

“…Still, in 9% of the treated patients, there is worsening of tinnitus, and in 4% of patients tinnitus occurs even though it did not exist before surgery (58). When compression of the vestibule-cochlear nerve by blood vessels is present, decompression surgical techniques can reduce tinnitus (59). Generally speaking, the effects of these tinnitus therapies are limited, indicating that preventive action on tinnitus risk factors is of primary and paramount public health importance.…”

Tinnitus – current literature review

“…Leczenie chirurgiczne polegające na dekompresji konfliktów naczyniowo-nerwowych może zatem spowodować ustąpienie objawów w tych przypadkach, ale dowody na to są jak do tej pory sprzeczne [11]. Chociaż niektórzy badacze donoszą o pozytywnych wynikach takiego leczenia [65], to doniesienia te są formułowane na podstawie badań obejmujących niewielką liczbę pacjentów [11].…”