Neurotology findings in patients with diagnosis of vascular loop of cranial nerves VIII in magnetic resonance imaging

Summary

Introduction: The vascular compression by redundant vessels under the VIII cranial nerves has been studied since the 80's, and many authors proposed correlations between the compression and the otoneurological findings (vertigo, tinnitus, hypoacusis, audiometry and electrophysiological findings).

Objective: Analyze and correlate the different signs and otoneurological symptoms, the audiological findings and its incidence over individuals with Vascular Loop (VL) diagnosis of VIII cranial nerves by magnetic resonance imaging (MRI).

Method: Retrospective study through the analysis of medical records of 47 patients attended in the otoneurology clinic of Clinical Hospital of UFPR. All the patients have MRI exams with compatible pictures of VL of the VIII cranial nerves.

Results: The tinnitus was the most frequent symptom, in 83% of the patients, followed by hypoacusis (60%) and vertigo (36%). The audiometry presented alterations in 89%, the brainstem evoked auditory potential in 33% and the vecto-electronystagmography in 17% of the patients. Was not found statistically significant relation between the buzz or hypoacusis, and the presence of VL in MRI. Only 36% of patients had complaints of vertigo, the main symptom described in theory of vascular compression of the VIII pair of nerve. As in the audiometry and in brainstem evoked auditory potential was not found a statistically significant relation between the exam and the presence of the VL in the RMI.

Conclusion: The results show independence between the findings of the RMI, clinical picture and audiological results (p > 0,05) suggesting that there are no exclusive and direct relation between the diagnosis of vascular loop in the MRI and the clinical picture matching.

Resumo

Introdução: A compressão vascular por vasos redundantes sobre o VIII par craniano vem sendo estudada desde a década de 80, e diversos autores propuseram correlações entre a compressão e os achados otoneurológicos (vertigem, zumbido, hipoacusia, audiometria e achados eletrofisiológicos).

Objetivo: Analisar e correlacionar os diferentes sinais e sintomas otoneurológicos, os achados audiológicos e sua incidência em indivíduos com diagnóstico de alça vascular (AV) de VIII par craniano por Ressonância Magnética (RM).

Método: Estudo retrospectivo através da análise de prontuários de 47 pacientes atendidos no ambulatório de Otoneurologia do Hospital de Clínicas da UFPR. Todos os pacientes possuíam exames de RM com imagens compatíveis com AV de VIII par craniano.

Resultados: O zumbido foi o sintoma mais frequente, em 83% dos pacientes, seguido de hipoacusia (60%) e vertigem (36%). A audiometria apresentava alterações em 89%, o PEATE em 33% e o VENG em 17% dos pacientes. Não foi encontrada relação estatisticamente significante entre o zumbido ou a hipoacusia e a presença de AV na RM. Somente 36% dos pacientes tinham queixas de vertigem, o principal sintoma descrito na teoria da compressão vascular do VIII par. Tanto na Audiometria quanto no PEATE não foi encontrada relação estatisticamente significante entre o exame e a presença de AV na RM.

Conclusão: Os resultados mostram independência entre os achados da RM, quadro clínico e resultados audiológicos (p > 0,05) sugerindo que não exista relação direta e exclusiva entre o diagnóstico de alça vascular na RM e o quadro clínico otoneurológico correspondente.

Keywords

vestibulocochlear nerve - tinnitus - hearing loss - audiometry - MRI (magnetic resonance imaging)

Palavras-chave

nervo vestibulococlear - zumbido - perda auditiva - audiometria - imagem por ressonância magnética

• Bibliographic References

• 1 Dandy WE. Concerning the cause of trigeminal neuralgia. Am J Surg 1934; 24: 447-55
• 2 Gardner WJ, Miklos MV. Response of trigeminal neuralgia to decompression of sensory root: discussion of cause of trigeminal neuralgia. JAMA 1959; 170: 1773-6
• 3 McKenzie KG. Intracranial division of the vestibular portion of the auditory nerve for Meniere's disease. Can Med Assoc J 1936; 34 (4) 369-81
• 4 Janetta PJ. Neurovascular cross-compression in patients with hyperactive dysfunction of the eighth cranial nerve. Surg Forum 1975; 26: 467-9
• 5 Janetta PJ, Moller MB, Moller AR. Disabling positional vertigo. NEJM 1984; 310: 1700-1705
• 6 Schwaber MK, Hall JW. Cochleovestibular nerve compression syndrome. I. Clinical features and audiovestibular findings. Laryngoscope 1992; 102 (9) 1020-9
• 7 Schwaber MK, Whetsell WO. Cochleovestibular nerve compression syndrome. II. Vestibular nerve histopathology and theory of pathophysiology. Laryngoscope 1992; 102 (9) 1030-6
• 8 McCabe BF, Harker LA. Vascular loop as a cause of vertigo. Ann ORL 1983; 92: 542-543
• 9 Moller MB. Vascular compression of the eighth cranial nerve as a cause of vertigo. Keio J Med 1991; 40 (3) 146-150
• 10 Parnes LS, Shimotakahara SG, Pelz D , et al. Vascular relationships of the vestibulocochlear nerve on magnetic resonance imaging. Am J Otol 1990; 11: 278-281
• 11 Moon I, Hain TC. Delayed Quick Spins following Vestibular Nerve Section Respond to Anticonvulsant Medication. Otol Neurotol 2005; 26: 82-85
• 12 Moller MB, Moller AR, Jannetta PJ, Sekhar L. Diagnosis and surgical treatment of disabling positional vertigo. J Neurosurg 1986; 64: 21-28
• 13 Brandt T. Vertigo, its multisensory syndromes, 2nd Ed. London: Springer Verlag; 1999
• 14 McDermott AL, Dutt SN, Irving RM, Pahor AL, Chavda SV. Anterior inferior cerebellar artery syndrome: fact or fiction. Clin Otolaryngol 2003; 28 (2) 75-80
• 15 Makins A, Nikolopoulos TP, Ludman C, O'Donoghue G. Is there a Correlation Between Vascular Loops and Unilateral Auditory Symptoms?. The Laryngoscope 1998; 1739-1742