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|Year : 2012 | Volume
| Issue : 5 | Page : 495-497
Microvascular decompression of cochleovestibular nerve in patients with tinnitus and vertigo
Li Zhang1, Yanbing Yu2, Yue Yuan2, Jun Xu2, Xialo Xu2, Jianguo Zhang1
1 Department of Neurosurgery, Beijing Tiantan Hospital, Affiliate of Capital University of Medical Sciences, Beijing, People's Republic of China,
2 Department of Neurosurgery, China-Japan Friendship Hospital, Beijing, People's Republic of China,
|Date of Submission||06-May-2012|
|Date of Decision||15-May-2012|
|Date of Acceptance||25-Aug-2012|
|Date of Web Publication||03-Nov-2012|
Department of Neurosurgery, Beijing Tiantan Hospital, Affiliate of Capital University of Medical Sciences, 6 Tiantan Xili, Chongwen District, Beijing 100050, People's Republic of China
Aim: The aim of this study was to investigate the patient selection, indications for operation, surgical methods and effects of microvascular decompression (MVD) for treatment of intractable and incapacitating tinnitus and vertigo. Materials and Methods: A total of 35 patients were recruited from January 2009 to June 2010 for the MVD surgery. Results: Arterial compression of cochleovestibular nerve was found in all the 35 patients. The immediate effect of MVD was observed in 22 patients with tinnitus and 10 patients with vertigo. The follow-up data for the effect of MVD showed complete resolution of tinnitus in 14 patients and vertigo in 6 patients. Conclusions: Vascular compression of cochleovestibular nerve in cerebellopontine angle may be one of the causes of intractable and incapacitating tinnitus and/or vertigo. MVD may be a safe and effective surgical procedure for treatment of severe tinnitus and/or vertigo in patients.
Keywords: Cranial nerve, microvascular decompression, tinnitus, vertigo
|How to cite this article:|
Zhang L, Yu Y, Yuan Y, Xu J, Xu X, Zhang J. Microvascular decompression of cochleovestibular nerve in patients with tinnitus and vertigo. Neurol India 2012;60:495-7
|How to cite this URL:|
Zhang L, Yu Y, Yuan Y, Xu J, Xu X, Zhang J. Microvascular decompression of cochleovestibular nerve in patients with tinnitus and vertigo. Neurol India [serial online] 2012 [cited 2013 Dec 20];60:495-7. Available from: http://www.neurologyindia.com/text.asp?2012/60/5/495/103194
| » Introduction|| |
The eighth cranial nerve is composed of vestibular and cochlear nerves. Vascular compression (NVC) in the cerebellopontine angle (CPA) of vestibulocochlear nerve may cause vertigo, tinnitus, deafness and other symptoms, causing great suffering to patients and affecting their quality of life, living and working.  Diagnosis and treatment of NVC of vestibulocochlear nerve is more difficult than other cranial nerve diseases. Microvascular decompression (MVD) is one of the preferred surgical methods for hemifacial spasm (HFS), trigeminal neuralgia (TN), glossopharyngeal neuralgia (GN) and other cranial nerve diseases. For vestibuloccochlear NVC, the place of MVD in regard to patient selection, indications for operation, surgical methods, clinical outcome measures and prevention of complications are not well studied. With the development of microscopic neuro-anatomy and microscopic neurosurgery technology, there is accumulating evidence for safe use of MVD. In this study, MVD was studied in 35 cases of vestibulocochlear NVC with incapacitating tinnitus and/or vertigo.
| » Materials and Methods|| |
MVD was done in 35 cases of vestibulocochlear NVC with intractable and incapacitating tinnitus and/or vertigo between January 2009 and June 2010. The study subjects included 22 patients of tinnitus, 10 patients of vertigo and 3 patients of both tinnitus and vertigo. The cohort included 22 women and 13 men and the average age was 53.4 years (range 37-67 years). The clinical characteristics of 35 patients were presented in [Table 1].
The procedure was done under general anesthesia. Patients were kept in lateral recumbent position with contralateral side down, head drooping 15°, rotating 10° to contralateral side and neck flexion slightly. A postauricular incision (3 ~ 5 cm length) parallel with hair line was made. The diameter of bone window was 1.5 ~ 2.0 cm between transverse sinus and sigmoid sinus. The dura mater was cut in inverted T-shaped or Y-shaped or ± shaped and suspended in soft tissue of incision. After exploring the CPA by the conventional surgical approach, a 4 mm wide brain spatula was used to lift cerebellar hemispheres. Then cerebrospinal fluid was slowly drained and the arachnoid outside of cisterna magna was cut in order to expose the glossopharyngeal and vagus nerves. Brain spatula, replaced into another 2 cm width, was placed on the flocculus cerebelli and retracted. After sharp dissection of the arachnoid between flocculus cerebelli and auditory nerve, the pontine cistern segment of facial-acoustic nerve was visible. Attention was paid not to damage the perforating arteries to brainstem and the internal auditory artery toward to internal auditory canal.
| » Results|| |
The arterial compression of cochleovestibular nerve was found in all the patients. The immediate effects of MVD in 22 patients with tinnitus included: Complete resolution of symptoms in 12 patients, partial relief in 6 patients and no effects in 4 cases. The immediate effects of MVD in 10 patients with vertigo included: Complete symptoms resolution in 5 patients, partial relief in 3 patients and no effect in 2 cases. All patients had a mean follow up of 18.6 months (range 12 to 29 months). The long term followed-up effects of MVD for patients with tinnitus was complete resolution of symptoms in 14 patients, partial relief in 7 patients and no effect in 4 patients. The cure rate and effective rate were 56% and 84%, respectively. The long-term follow up effects of MVD for patients with vertigo was complete resolution of symptoms in 6 patients, partial relief in 3 patients and no effects in 4 patients. The cure rate and effective rate were 46.2% and 69.2%, respectively.
| » Discussion|| |
Intractable and incapacitating tinnitus and/or vertigo are often refractory to conservation treatment. However, these incapacitating symptoms often result in great suffering to patients and also impair their nautical living and working. Trigeminal neuralgia, hemifacial spasm, and glasso-pharyngeal neuralgia are some the syndromes that result from NVC due to an abnormal vessel of the respective cranial nerves. Compression due to an abnormal vessel of the vestibulocochlear nerve in CPA may cause symptoms such as vertigo, tinnitus and hearing impairment and relief of these symptoms may be achieved by MVD. , Subsequently several studies had reported their experience of using MVD in these patients. In recent times, many researches have been carried out on the clinical practice of MVD, and experiences on MVD have also been reported. However, the experiences are mostly confined to a few case series and there is lack of experience with large series. There has been a difficulty to establish indications for MVD in patients with intractable vertigo and tinnitus. Some investigators believed that magnetic resonance imaging (MRI) has high sensitivity and specificity in demonstrating vascular compression. ,,,, However, caution may be needed when using pre-operation MRI to demonstrate the offending vessels. ,, The cochlear nerve as a sensory cranial nerve has longer root entry zone (REZ) when compared with the motor cranial nerves. REZ of the cochlear nerve runs through the entire CPA cistern, ,,,, starting from the internal auditory foramina. , Therefore, we suggested that all surrounding blood vessels from the internal auditory foramina to REZ region, should be pushed aside and separated with Teflon cotton pad, and all the tissue adhesion should be sharply dissected. In our follow up data of MVD in treating intractable and incapacitating tinnitus and vertigo, the total efficacy was 84% and 69.2%, respectively. Compared to results seen with other cranial nerve diseases, this is less effective. Facial nerve complications may result with MVD for tinnitus and vertigo. In the present study, patients benefited from MVD if their course of diseases were shorter than three years. ,,, Therefore, it is advisable to go for surgical intervention as soon as possible. , MVD is less beneficial for patients with bilateral tinnitus or tinnitus with severe hearing loss. ,,,, It is not surprising to find that appropriate MVD treatment alleviates tinnitus and/or vertigo in patients with abnormal brainstem auditory evoked potentials (BAEP) before surgery. ,
Surgeons are usually concerned about possible postoperative complications and hence restrict in decompressing the offending vessel. To resolve the above mentioned conflict, we highly recommend these rules: 1) Sharp dissection to separate the flocculus and cochlear nerve, thus avoiding excess stretching of the nerve; 2) avoiding stretching of the anterior inferior cerebellar artery (AICA) and the internal auditory artery; 3) monitoring BAEPs for the entire duration of the operation, and pausing the operation if a lower amplitude of P5 is observed, until the amplitude returns to normal and stabilizes; 4) if possible, direct monitoring of cochleae compound action potentials (CAPs) after exposing the nerve and three minutes suspension of the operation when the latency exceeds 1 ms; and 5) the aid of endoscope to locate all the offending vessels and/or to protect perforating arteries.
Our clinical experience has shown that vascular compression on cochlear nerve is one of the major causes of intractable and incapacitating tinnitus and/or vertigo, for which MVD serves as a safe and effective treatment. It should be noted that the present study has the limitations of a small sample size, and relatively short follow up time. Further studies are desirable with more subjects and further evaluation methods.
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