Cochleovestibular Nerve Research Articles

Traditional Open versus Purely Endoscopic Microvascular Decompression for Treatment of Vascular Compression Syndromes

Objective: The purpose of this study was to evaluate the technique used and the outcomes for patients who underwent endoscopic microvascular decompression (EVD) for the treatment of trigeminal neuralgia (TGN), hemifacial spasm (HFS), and cochleovestibular nerve compression (CNC) syndromes.

Bilateral implantation in children with cochleovestibular nerve hypoplasia

To report on the outcomes of sequential bilateral cochlear implantation (CI) in children with inner ear malformation. The study design is a retrospective case study. The setting is a tertiary reference center. Two children presenting a profound bilateral congenital hearing loss with bilateral hypoplasia of the cochleovestibular nerves and hypoplasic external semicircular canal had a cochlear implant at respectively 16 months and 33 months. A second implant was proposed at respectively 17 and 20 months after the first implant. The main outcome measures are audiometry, perceptive results in closed and open set words (CSW and OSW) and oral production at follow-up. The first cochlear implant gave respectively mean thresholds at 60 dB and 70 dB. Bilateral CI showed mean threshold at respectively 40 dB and 55 dB. In case 1, perceptive assessment was 83% and 70% in respectively CSW and OSW with oral production and comprehension of sentences after 1 year follow-up. In case 2, the perceptive assessment showed no perceptive or linguistic evolution at 6 months follow-up. In cochleovestibular nerve hypoplasia, bilateral implantation could be discussed in cases of limited result after unilateral implant.

Radiographic Analysis of Cochlear Nerve Vascular Compression

We analyzed whether radiographically demonstrated anterior inferior cerebellar artery (AICA) vascular compression of the cochleovestibular nerve in asymmetric hearing loss could be correlated to either the symptomatic ear or to cochlear nerve diameter. We undertook a retrospective case-control study in which patients were enrolled into a database if audiometry demonstrated asymmetry of 20 dB at one frequency, asymmetry of 10 dB at two frequencies, or a difference of 20% on word recognition scores. If AICA vascular contact was demonstrated on subsequent magnetic resonance imaging of the cerebellopontine angle, patients were included in the study. Patients with vestibular schwannoma or Meniere's disease were excluded. The AICA contact was graded by a blinded neuroradiologist according to criteria proposed by McDermott et al. The cross-sectional area of the cochlear nerve was measured. Symptomatic ears could be correlated to a decreased cochlear nerve diameter, but not to the degree of AICA penetration into the internal auditory canal. AICA vascular compression of the cochleovestibular nerve does not appear to correlate to hearing loss or to cochlear nerve diameter. The finding of decreased cochlear nerve diameter in symptomatic ears implies an alternative mechanism for asymmetric hearing loss.

Clinical manifestations and imaging features of peripheral vestibular paroxysmia: a report of 7 cases

To investigate the clinical manifestations and imaging features of peripheral vestibular paroxysmal (PVP). The clinical data, including magnetic resonance tomographic angiography (MRTA), of 7 PVP patients, 1 male and 2 females, aged 40-72, were retrospectively analyzed. (1) All 7 patients had non-specific cochleovestibular symptoms, e.g., recurrent vertigo and continuous dizziness. (2) The predominant symptom was transient vertigo or dizziness with the sudden change of head position. (3) MRTA showed cross of the cochleovestibular nerve (CNV) and blood vessel in all patients. (4) Carbamazepine and sibelium succeeded to relieve the symptoms. Compression of the cranial nerve VIII by crossing vessel thereon may be the mechanism of PVP which can be identified and diagnosed clinically.

Endoscopic Vascular Decompression

This article describes the technique and reports the results of endoscopic vascular decompression (EVD) in patients with trigeminal neuralgia (TGN), hemifacial spasm (HFS), and cochleovestibular nerve compressive syndrome. Retrospective case review. This study evaluates the outcome and length of stay (LOS) of 20 patients who underwent EVD for vascular compressive disorders from 2005 to 2007. It also evaluates LOS in 41 patients who underwent traditional microvascular decompression (MVD) by the same surgeons from 1999 to 2004. Eighty-six percent (12 of 14) patients had resolution of their TGN, and 80% (4 of 5) had resolution of their HFS. There were no major complications. The EVD patients had an average LOS of 2.36 days as compared with 4.36 days for the MVD patient group (p < 0.001). Endoscopic vascular decompression for patients with vascular compressive syndromes such as TGN and HFS is a safe and equally effective procedure when compared with the traditional and widely successful MVD surgery, with the added benefit of less morbidity and shorter hospital stays.

Neurovaskularna kompresija (konflikt)

Since Dandy first reported vascular compression of the trigeminal nerve, the concept of neurovascular compression syndrome for trigeminal neuralgia and hemifacial spasm (HFS) has been accepted, and neurovascular decompression has been performed for this condition. The further investigations indicated that some other clinical syndromes such as glossopharyngeal neuralgia, disabling positional vertigo, tinnitus, geniculate neuarlgia, spasmodic torticolis, essential hypertension, cyclic oculomotor spasm with paresis and superior oblique myokymia also may be initiated by vascular compression of the glossopharyngeal, cochleovestibular, intermediate, accessory, oculomotor and trochlear nerves or the ventrolateral medulla oblongata. In this study several hypotheses regarding the development of cranial nerves vascular compression syndromes are presented. It is alsoemphasized the value of high-resolution magnetic resonance tomographic angiography for visualization of vascular compression. The most frequent clinical syndromes caused by vascular compressionof the cranial nerves are discussed regarding the pathogenesis, symptomes and therapy. We present our series of 124 patients with preoperative evidently positive finding of vascular compression to the trigeminal nerve (MRI). Microvascular decompression (MVD) was performed in all of them. Initial postoperative result was excellent in 110/124 (89%) patients,while in 11/124 (9%) patients the pain relief was satisfactory. In the remaining three patients MVD failed. Recurrence of pain after two years reached 19%. Complications were related to diplopia associated with transient fourth nerve dysfunction in 5 (4%) patients, facial motor dysfunction in 4 (3%) patients, transient facial hypesthesia in 27 (22%) patients and partially hearing loss in 4 (3%) patients. Cerebellar hemorrhagic infarction occurred in 1 (0.8%) patient and cerebrospinal fluid leaks appeared in two (1.6%) cases. There was no lethal outcome.

Three-dimensional visualization of vertebrobasilar system aneurysms in a vertigo patient

Cerebral artery fenestration refers to a division in the lumen of an artery leading to two distinct endothelium-lined channels. At the site of turbulent flow, fenestration may predispose to an aneurysm formation. In this study, a 45-year-old woman suffered an acute vertiginous attack after cervical manipulation. The MRI scan demonstrated basilar artery duplication and tortuous left distal vertebral artery impinging on the cisternal segment of the cochleovestibular nerve. Subsequent three-dimensional (3D) reconstruction by MR imaging showed vertebrobasilar artery fenestrations with aneurysms. Unfortunately, subarachnoid hemorrhage occurred 6 days later, and the patient became comatose one year after presentation. In summary, subarachnoid hemorrhage caused by vertebrobasilar system aneurysms is a life-threatening event. Delineating the configuration by 3D-reconstruction of MR images allows more accurate diagnosis and more effective management.

Radio-anatomie utile de l’oreille

Good anatomical knowledge is necessary to make an effective diagnosis in ear pathology. The purpose of this article is to summarize the main landmarks of the ear. Anatomic definitions of the external ear, middle ear, and bony labyrinth are described on routine spiral CT, and the anatomic definition of the membranous labyrinth and the cochleovestibular nerve on MRI is reviewed.

Internal auditory canal stenosis in congenital sensorineural hearing loss

Sensorineural hearing loss (SNHL) due to internal auditory canal (IAC) stenosis with hypoplasia of the cochleovestibular nerve is a rare disorder. The diagnosis of the IAC stenosis requires both high resolution computed tomography scan (HRCT) and magnetic resonance imaging (MRI). A retrospective review over 6 years in an academic tertiary referral center was performed. Six patients with congenital SNHL were diagnosed with congenital IAC stenosis. Four had unilateral and two had bilateral IAC stenosis after imaging. MRI showed hypoplastic vestibulocochlear nerve in all cases. This paper highlights the importance of imaging in diagnosing IAC stenosis and detecting the presence of cochleovestibular nerve in cases of congenital SNHL.

Favorable Outcome of Cochlear Implant in VIIIth Nerve Deficiency

To report on the outcomes of cochlear implantation (CI) in a child with cochleovestibular nerves (CVN) hypoplasia. Retrospective case review. Tertiary referral center, University hospital. An 18-month-old child with profound bilateral congenital hearing loss and bilateral hypoplasia of the CVN at imaging. Left CI at age 29 months with a Nucleus Contour device (Cochlear Ltd., Lane Cove, New South Wales, Australia) after unsatisfactory results of hearing aid use for 10 months. Speech perception tests, behavioral observation, electrophysiologic tests, and cognitive evaluation. Although the child scores poorly in every perceptive category with the CI alone, the device greatly enhances his speech understanding with the hearing aid in the opposite ear. In the bimodal condition, his words and sentences identification, recognition, and comprehension far exceed the monaural figures. The Meaningful Auditory Integration Scale (MAIS) tests reaches a score of 26/40, and the MacArthur's questionnaires confirm the improvement of language production and comprehension. These results became noticeable after 5 to 6 months and continued to improve up to the 10th month. The child's cognitive scores and overall performance competences greatly benefit from the CI, with the mental age overcoming the chronological age. We can confirm the chance of achieving satisfactory results by CI even when the imaging of CVN is doubtful and the electrophysiological tests are disappointing. In our experience, a CI in Type IIb dysplasia of the CVN is a feasible option, provided that the candidate shows some responses at aided audiogram and at least minimal signs of language development. Adequate counseling is necessary for these children because the expected outcome is somewhat lower than that of their deaf peers with normal appearance of the nerves.

Magnetic resonance imaging based classification of anatomic relationship between the cochleovestibular nerve and anterior inferior cerebellar artery in patients with non-specific neuro-otologic symptoms

In this study, we aimed to assess anatomical relationship between the anterior inferior cerebellar artery (AICA) and cochleovestibular nerve (CNV) in patients with non-specific cochleovestibular symptoms using magnetic resonance imaging (MRI). One-hundred and forty patients with non-specific neuro-otologic symptoms were assessed using cranial and temporal MRI. Classification was performed according to four different types of anatomical relationship observed between the AICA and CVN. In type 1 (point compression), the AICA compresses only a limited portion of the CVN. In type 2 (longitudinal compression), the AICA approaches the CVN as both traverse parallel to each other. In type 3 (loop compression), the vascular loop of the AICA encircles the CVN. In type 4 (indentation), the AICA compresses the CVN so as to make an indentation in the nerve. The anatomical relationship between the CVN and AICA was encountered in 19 out of 140 (13.6%) patients (20 ears). The VCC was unilateral in 18 patients (94.7%) and bilateral in one patient (5.3%). There was no other vascular structure causing VCC to the CVN except for vertebral artery that was seen in 2 out of 140 patients (1.4%). These were unilateral cases. There were tinnitus, vertigo or dizziness, hearing loss, and both hearing loss and vertigo in 5 (25%), 13 (65%), 1 (5%) and 1 (5%) ears of 20 patients, respectively. There was no relationship between the cochleovestibular symptoms and type of compression (p>0.05). Neurovascular relationship between the CVN and AICA can be imaged properly using MR and MR based classification may help reporting this relationship in a standard way. Although, MR images can show the anatomical relationship accurately, diagnosis of vascular conflict should not be based on imaging findings alone.

Dlx gene expression during chick inner ear development

Members of the Dlx gene family play essential roles in the development of the zebrafish and mouse inner ear, but little is known regarding Dlx genes and avian inner ear development. We have examined the inner ear expression patterns of Dlx1, Dlx2, Dlx3, Dlx5, and Dlx6 during the first 7 days of chicken embryonic development. Dlx1 and Dlx2 expression was seen only in nonneuronal cells of the cochleovestibular ganglion and nerves from stage 21 to stage 32. Dlx3 marks the otic placode beginning at stage 9 and becomes limited to epithelium adjacent to the hindbrain as invagination of the placode begins. Dlx3 expression then resolves to the dorsal otocyst and gradually becomes limited to the endolymphatic sac by stage 30. Dlx5 and Dlx6 expression in the developing inner ear is first seen at stages 12 and 13, respectively, in the rim of the otic pit, before spreading throughout the dorsal otocyst. As morphogenesis proceeds, Dlx5 and Dlx6 expression is seen throughout the forming semicircular canals and endolymphatic structures. During later stages, both genes are seen to mark the distal surface of the forming canals and display expression complementary to that of BMP4 in the vestibular sensory regions. Dlx5 expression is also seen in the lagena macula and the cochlear and vestibular nerves by stage 30. These findings suggest important roles for Dlx genes in the vestibular and neural development of the avian inner ear.

Preventing internal auditory artery vasospasm using topical papaverine: an animal study.

Internal auditory artery (IAA) spasm is thought to be one of the causes of postoperative sensory hearing loss after attempted hearing preservation removal of an acoustic neuroma. The use of topical papaverine, a nonspecific vasodilator, to prevent vascular insufficiency to the inner ear and to improve hearing outcomes has been suggested but not proven. Vasospasm was mechanically induced by compressing the IAA in the control ears of six rabbits after application of topical saline. The subsequent reduction of cochlear blood flow (CBF) was measured using a laser-Doppler (LD) flow-monitoring technique. Functional loss of cochlear activity was verified with distortion product otoacoustic emissions (DPOAE). The contralateral experimental ears were treated with the topical application of papaverine directly to the IAA and cochleovestibular nerve complex. CBF and DPOAE were compared between the control and papaverine treated ears for 3-minute and 5-minute IAA compressions. Every control ear demonstrated some degree of postcompression IAA vasospasm (i.e., reduced CBF) and reduction of DPOAE. Nearly complete recovery of CBF and DPOAE to baseline was observed in all of the papaverine treated ears. An animal model of IAA vasospasm was described. Mechanically induced vasospasm of the IAA was prevented by the topical application of papaverine. These findings have clinical implications for surgical procedures involving the internal auditory canal/cerebellopontine angle such as acoustic neuroma removal.

Labyrinthitis and sensorineural hearing loss—an unusual complication of acute otitis media in adult

Auditory neuropathy (AN) is a specific hearing disorder with abnormal auditory neural responses in the presence of normal cochlear function. Affection of vestibular portion of cochleo-vestibular (VIII) nerve was only reported in few studies.To evaluate the cochleo-vestibular function in these patients and to detect any relationship between both cochlear and vestibular functions.The study was conducted on forty (AN) patients. All subjects were submitted to: full audiological test battery; history taking, clinical otological examination, basic audiological evaluation, Auditory Brainstem Response (ABR), Transient Evoked Otoacoustic Emissions (TEOAEs) and threshold equalizing test (TEN). Vestibular test battery; (vestibular evoked myogenic potential (VEMP) and VNG test battery).Audiological test battery confirmed the audiological criteria for auditory neuropathy reported in the literature. Results of this work showed that, there was preservation of TEOAE in all patients. Also, there was an increase in amplitude of CM in AN. Moreover, all AN patients showed presence of dead regions that started first in low frequencies and with increase number of dead regions the mid and high frequencies also affected. In addition to that the vestibular function tests showed that VEMP was preserved bilaterally in 15 patients, unilateral in 10 patients and absent in 15 patients. On the other side, VNG showed normal central vestibular system with unilateral weakness in 10 ears only.Patients with auditory neuropathy could also have vestibular neuropathy. Vestibular neuropathy could be classified into three groups: superior vestibular neuropathy, inferior vestibular neuropathy and superior/inferior vestibular neuropathy.

Cochlear implantation in children with inner ear malformations: report of two cases

Cochlear implantation of congenitally deaf children with inner ear malformations is gaining special interest. Although the number of the reported cases is increasing, the decision for implantation needs thorough investigation. Preoperative evaluation, surgical approach and postoperative follow-up can be challenging. Study design: A retrospective analysis of two cases with inner ear malformations. Patients: One patient was a 3-year-old-girl who had cochlear and cochleovestibular nerve aplasia on the left side and incomplete partition on the other side. The other patient was a 5-year-old-boy who had hypoplastic cochlea on both sides. Both of them also had vestibular anomalies. Cases were implanted by using multichannel cochlear implant. Results: No complications were encountered. Both patients responded to acoustic stimuli, and their speech perception skills were improved. After 10 months of cochlear implant use, their results seem encouraging. Conclusion: Except cochlear or cochleovestibular nerve agenesis, inner ear malformations cannot be accepted as a contraindication for cochlear implantation. Although there can be difficulties during the surgery or in the postoperative period, patients with inner ear malformations can also benefit from cochlear implantation. It is essential that all possible complications and postoperative performance should be discussed with the parents.

内耳障害患者のグルクロン酸含有特異酸性糖脂質抗体に関する研究

Glycosphingolipids are molecules present on the surface of normal nerve cells and are considered antigenic. Recent studies have isolated these antigens in vestibular neuroepithelia, cochleovestibular nerves and the endolymphatic sac. The purpose of this study was to determine the presence of antibodies against the glycosphingolipid antigen, sulfoglucuronyl paragloboside (SGPG), in the sera of patients suspected of autoimmune inner ear disease. The sera of a total 41 patients, including cases of progressive sensorineural hearing loss (PSNHL) (n= 19), sudden deafness (SD) (n = 8), Ménière's disease (n = 9), mumps hearing loss (n = 5), were tested for antibodies against the SGPG antigen. Antibody titers were determined by the microtiter ELISA method. Antibody titers were elevated in 36.8% of patients with PSNHL,25.0% of sudden deafness patients, while no elevation was observed in Mniere' s disease patients and mumps patients. Because SGPG antigens have been recently isolated in the inner ear, especially in the cochleovestibular nerve, these structures can potentially become targets for anti-SGPG antibodies.

Ramsay-Hunt 증후군 환자의 다발성 뇌신경병변

Background and Objectives: Ramsay-Hunt syndrome is characterized by otalgia, vesicular eruption on the pinna, retroauricular area or face and facial palsy. It is caused by Herpes zoster infection of the facial nerve in patients of low immune state. Sometimes other cranial nerves can be involved in this syndrome but there is not much information about these cases because of its rare incidence. The purpose of this report is to study the characteristics of cranial polyneuropathy in Ramsay Hunt syndrome and the clinical differences between the groups of Ramsay-Hunt syndrome with and without polyneuropathy. Materials and Methods: There were 215 cases of facial nerve palsy for 14 years in Yongdong Severance Hospital including 37 cases of Ramsay-Hunt syndrome which were reviewed retrospectively among them. The duration of their clinical follow up was more than 6 months. Results: Cochleovestibular nerve was involved most frequently in Ramsay Hunt syndrome and it was also noted that the symtoms and signs of trigeminal, abducens, glossopharyngeal, vagus and accessory nerves. There was female predominance and higher mean age in the cranial polyneuropathy group. It had worse recovery rate than typical Ramsay-Hunt syndrome but there was no statistical significance. Conclusion: It is suggested that cranial polyneuropathy in Ramsay-Hunt syndrome has different clinical findings from typical Ramsay Hunt syndrome and it is required that evaluation of more cases, study of the pathogenesis, and setting of the diagnostic criteria.

Isolated congenital internal auditory canal atresia with normal facial nerve function

The internal auditory canal forms as a result of mesoderm enveloping the eighth cranial nerve in the developing embryo. The mesoderm eventually transforms into cartilage and ultimately ossifies around the nerve, forming the internal auditory canal. It is theorized that atresia or stenosis of the internal auditory canal results from altered cochleovestibular nerve development secondary to faulty chemotactic mechanisms or a lack of end organ targets. Unilateral internal auditory canal anomalies are frequently seen in conjunction with other inner ear anomalies and occasionally with middle or external ear anomalies. Infrequently, it will occur as either an isolated or bilateral finding, but rarely simultaneously. The few citations of isolated, unilateral or bilateral internal auditory canal anomalies that are reported in the literature are usually associated with other systemic developmental anomalies, such as, cardiac septal defects, polycystic kidney disease, skeletal deformities and duodenal atresia. We present a case report of a patient with bilateral, congenital, internal auditory canal atresia and cochleovestibular deficits but, normal facial nerve function. A review of the literature is discussed as well as diagnostic considerations and treatment options including audiologic and communication rehabilitation.

内耳道内血管輪と神経の病理組織学的研究

内耳道内血管輪と神経の病理組織学的研究

上咽頭癌によるGarcin症候群の側頭骨病理所見

The histopathological findings in the temporal bone of a 61-year-old male with Garcin syndrome due to nasopharyngeal cancer are reported. The patient complained of unilateral disturbance of the second to twelveth cranial nerves, except for the olfactory nerve. Approximately three months prior to death, the results of his audiogram demonstrated deafness.The unilateral temporal bone was destroyed by extensive invasion at the petrous apex, tympanic cavity and mastoid air cells. In addition, the internal auditory canal showed tumor cell infiltration and hemorrhage. The facial and cochleovestibular nerves were also completely replaced by tumor cells and hemorrhage. Although the sensory organs of the cochlear, vestibule and semicircular canals were destroyed, tumor cells were not found in the membranous labyrinth.It was thought that audiometric and vestibular dysfunctions, and facial nerve palsy were caused by severe infiltration of tumor cells into the internal auditory canal.