The existence of Vascular Compression Syndromes (VCS), and especially here with the compression of the VIII pair, was initially inferred by analogy to the hemifacial spasm syndrome, in which is well accepted that the cause is an aberrant vessel compressing the nerve. The known histology would be consistent with the occurrence of a syndrome of neurovascular compression of the eight cranial nerve, in any point of the trajectory, since the brainstem to the IAC. He found the transition area of the eight cranial nerve varying from the brainstem to the bottom of the Inner Auditory Canal (IAC). LANG showed that the central segment of the 8th cranial pair has a length of 10mm (6 to 15 mm) and an intracisternal length of 15mm (8,5 to 22mm). It was suggested that this pathological procedure was restricted to the entrance area of the cranial nerve root, that being the junction area between central and peripheral myelin, where defects might occur. This results in a reorganization of the nervous nucleus causing nervous hyperfunction. Though MCKENZIE (3) suggested in 1936 that the Ménière Disease might be caused by an abnormal relation of the anterior inferior cerebellar artery (AICA) with the 8th cranial nerve, this concept was not reintroduced until 1975, when JANETTA (4) proposed that the redundant arterial loops at the cerebellar angle point (CAP) might interfere with the eight cranial pair resulting in symptoms of grave vertigo, tinnitus and auditory sensory neural loss.Īll pathophysiological theories are based on a common theme: a redundant vessel adhering to a cranial nerve causing chronic ectopic excitation. These presentations are known as compressive syndromes, which include hemifacial spasms, glossopharyngeal neuralgia, geniculate neuralgia, and, more recently, a syndrome of the compression of the vestibule-cochlear nerve. This concept was then extensively expanded to try to explain disorders of various cranial nerves. Vascular loop causing compression of the 5th cranial nerve resulting in trigeminal neuralgia was firstly suggested by DANDY in 1934 (1), and later, by GARDNER and MIKLOS (2) in 1959. Vascular compression by anomalous or redundant vessels over cranial nerves, and the establishment of statistically relevant correlation between compression and the neurological symptoms have been studied by several authors since the 1930's 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. 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. Only 36% of patients had complaints of vertigo, the main symptom described in theory of vascular compression of the VIII pair of nerve. Was not found statistically significant relation between the buzz or hypoacusis, and the presence of VL in MRI. The audiometry presented alterations in 89%, the brainstem evoked auditory potential in 33% and the vecto-electronystagmography in 17% of the patients. Results: The tinnitus was the most frequent symptom, in 83% of the patients, followed by hypoacusis (60%) and vertigo (36%). All the patients have MRI exams with compatible pictures of VL of the VIII cranial nerves. Method: Retrospective study through the analysis of medical records of 47 patients attended in the otoneurology clinic of Clinical Hospital of UFPR.
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). 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). Vestibulocochlear nerve, tinnitus, hearing loss, audiometry, MRI (magnetic resonance imaging).
Maria Theresa Costa Ramos de Oliveira3, Heloisa Nardi Koerner3. Mendes2, Ronaldo Vosguerau3, Marcos Mocellin4, Neurotology findings in patients with diagnosis of vascular loop of cranial nerves VIII in magnetic resonance imaging. Grocoske FLB, Mendes RCCG, Vosguerau R, Mocellin M, Oliveira TCR, Koerner HN, et al.
0 kommentar(er)
