Why not the eighth nerve? Neurovascular compression--probable cause for pulsatile tinnitus

Microvascular decompression for tinnitus: systematic review

OBJECTIVE

The objective of this study was to examine operative outcomes in cases of microvascular decompression (MVD) of cranial nerve (CN) VIII for tinnitus through a critical review of the literature.

METHODS

Forty-three English-language articles were gathered from PubMed and analyzed. In this review, two different case types were distinguished: 1) tinnitus-only symptomatology, which was defined as a patient with tinnitus with or without sensorineural hearing loss; and 2) mixed symptomatology, which was defined as tinnitus with symptoms of other CN dysfunction. This review reports outcomes of those with tinnitus-only symptoms.

RESULTS

Forty-three tinnitus-only cases were found in the literature with a 60% positive outcome rate following MVD. Analysis revealed a 5-year cutoff of preoperative symptom duration before which a good outcome can be predicted with 78.6% sensitivity, and after which a poor outcome can be predicted with 80% specificity.

CONCLUSIONS

As the 60% success rate is more promising than several other therapeutic options open to the chronic tinnitus sufferer, future research into this field is warranted.

Disabling vertigo and tinnitus caused by intrameatal compression of the anterior inferior cerebellar artery on the vestibulocochlear nerve: a case report, surgical considerations, and review of the literature

Microvascular compression of the vestibulocochlear nerve is known as a cause of tinnitus and vertigo in the literature, but our review of the literature shows that the compression is usually located in the cerebellopontine angle and not intrameatal.

We present a case of intrameatal compression of the anterior inferior cerebellar artery (AICA) on the vestibulocochlear nerve of a 40-year-old woman with symptoms of disabling vertigo and intermittent high-frequency tinnitus on the left side without any hearing loss for ∼ 4 years. Magnetic resonance imaging of the brain did not show any abnormality, but magnetic resonance angiography showed a left intrameatal AICA loop as a possible cause of the disabling symptoms. After the exclusion of other possible reasons for disabling vertigo, surgery was indicated. The intraoperative findings proved the radiologic findings. The large AICA loop was found extending into the internal auditory canal and compressing the vestibulocochlear nerve. The AICA loop was mobilized and separated from the vestibulocochlear nerve.

The patient's symptoms resolved immediately after surgery, and no symptoms were noted during 2 years of follow-up in our clinic. Her hearing was not affected by the surgery.

In addition to other common reasons, such as acoustic neuroma, disabling vertigo and tinnitus can occur from an intrameatal arterial loop compression of the vestibulocochlear nerve and may be treated successfully by drilling the internal acoustic meatus and separating the arterial conflict from the vestibulocochlear nerve.

Persistent primitive trigeminal artery: an unusual cause of vascular tinnitus

Pulsatile tinnitus is generally of vascular origin and can be due to arterial, venous, or systemic causes. While certain congenital anatomical variants and arterial vascular loops have been commonly found in symptomatic patients undergoing imaging, persistent primitive trigeminal artery in association with isolated tinnitus is unusual. Thus we report a patient with unilateral isolated pulsatile tinnitus who was evaluated with magnetic resonance angiography and was found to have a persistent primitive trigeminal artery. We also briefly discuss vascular tinnitus as well as the embryology, imaging, and classification of persistent primitive trigeminal artery with the clinical implications.

Pulsatile tinnitus: contemporary assessment and management

PURPOSE OF REVIEW

Pulsatile tinnitus is an uncommon otologic symptom, which often presents a diagnostic and management dilemma to the otolaryngologist. The majority of patients with pulsatile tinnitus have a treatable cause. Failure to establish correct diagnosis may have disastrous consequences, because a potentially life-threatening, underlying disorder may be present. The purpose of this review is to familiarize the otolaryngologist with the most common causes, evaluation, and management of pulsatile tinnitus.

RECENT FINDINGS

The pathophysiology, classification, various causes, evaluation, and management of the most common causes of pulsatile tinnitus are presented in this review.

SUMMARY

Pulsatile tinnitus deserves a thorough evaluation and, in the majority of cases, there is a treatable underlying cause. The possibility of a life-threatening cause needs to be ruled out in every patient with pulsatile tinnitus. The otolaryngologist should be familiar with the evaluation and management of this symptom.

Endovascular treatment of pulsatile tinnitus caused by dural sinus stenosis

A patient presenting with progressive pulsatile tinnitus was found to have an ipsilateral dural sinus stenosis. This problem was successfully treated by an endovascular approach with angioplasty and subsequent sinus stenting. The diagnostic evaluation, therapeutic method, and follow-up concerning this problem and its treatment are discussed.

Somatosensory pulsatile tinnitus syndrome: somatic testing identifies a pulsatile tinnitus subtype that implicates the somatosensory system

A new tinnitus syndrome is described: high-pitched, cardiac-synchronous tinnitus, whose pulsations are suppressed by strong contractions or compressions of the neck and jaw muscles (somatic testing). 14 cases, 6 non-lateralized and 8 unilateral, are reported. In the non-lateralized cases, onset was bilateral. In the one intermittent case, while her tinnitus was absent her pulsatile tinnitus could be induced by somatic testing. No etiology was found from physical examination, imaging, or ancillary testing. Because these cases of pulsatile tinnitus can be both induced and suppressed by activation of the somatosensory system of the head or upper lateral neck, we propose that this syndrome is occurring from (a) cardiac synchronous somatosensory activation of the central auditory pathway or (b) failure of the somatosensory-auditory central nervous system interactions to suppress cardiac somatosounds.

Pulsatile Tinnitus: A Review of the Literature and an Unusual Case of Iatrogenic Pneumocephalus Causing Pulsatile Tinnitus

BACKGROUND

Pulsatile tinnitus is frequently attributed to identifiable and treatable causes, in contrast to the more common subjective non-pulsatile tinnitus. It usually originates from vascular structures as a result of either increased blood flow or lumen stenosis; atherosclerotic carotid or subclavian artery disease; arterial, venous, or arteriovenous malformations, fistulas, or dissection; and paragangliomas. Other causes have also been reported, with often unclear pathophysiology.

OBJECTIVE

The aim of this paper is to present a case of pulsatile tinnitus secondary to iatrogenic pneumocephalus and to review the literature on pulsatile tinnitus.

SUBJECT

A 48-year-old white woman had a roaring, very disturbing, pulsatile tinnitus after the removal of a cerebellar lobe meningioma. When the patient experienced the symptom of tinnitus, a pulsatile movement of the tympanic membrane could be clearly seen, and this was synchronous with the patient's heartbeat. Computed tomography revealed an epidural pneumocephalus in the left posterior fossa communicating freely with the air cell system of the left mastoid cavity without any sign of residual tumor. A simple mastoidectomy was performed. The whole air cell system was removed and the mastoid cavity was filled with abdominal fat. After the operation, the pulsatile tinnitus ceased completely and the pneumocephalus disappeared gradually. The patient is free of symptoms 11 months after surgery.

CONCLUSION

Otologists, neurosurgeons, and skull base surgeons should be aware of this surgical complication and be careful to identify any accidental opening to the air cell system of the temporal bone and meticulously close it when it happens. The review of the literature leads to the conclusion that pulsatile tinnitus should be thoroughly investigated, as it may be related to diseases that may have serious complications.

Pulsatile tinnitus

Pulsatile tinnitus is an uncommon otologic symptom, which often presents a diagnostic and management dilemma to the otolaryngologist. This symptom always deserves a thorough evaluation to avoid disastrous consequences from potentially life-threatening associated pathology. In most pulsatile tinnitus patients a treatable underlying etiology can be identified.

Role of angiography in the evaluation of patients with pulsatile tinnitus

OBJECTIVES/HYPOTHESIS

Pulsatile tinnitus in the face of normal findings on otoscopy is a common otological diagnostic dilemma and can be due to serious vascular malformations such as transverse or sigmoid sinus dural arteriovenous fistula (transverse or sigmoid sinus [TS] DAVF). Left untreated, TS DAVF may result in significant morbidity and mortality. TS DAVF can be suspected or diagnosed with computed tomography (CT), magnetic resonance imaging (MRI), and magnetic resonance angiography (MRA), with the gold standard being angiography. Our objective was to assess the utility of these various diagnostic modalities in the diagnosis of dural arteriovenous fistula.

STUDY DESIGN

Retrospective clinical review.

METHODS

Between 1986 and 1996, 54 patients were evaluated and treated for TS DAVF. Between 1996 and 1999, an additional 33 patients underwent MRI combined with MRA for the evaluation of pulsatile tinnitus. A retrospective review of the medical records for both groups, with special attention to clinical presentation, diagnostic evaluation, therapy, and outcome, was performed.

RESULTS

All patients had pulsatile tinnitus with normal findings on otoscopy. CT scan was relatively insensitive in the detection of TS DAVF. MRI and MR/MRA were significantly more sensitive than CT. In the evaluation of patients with subjective pulsatile tinnitus, MRI/MRA defined anatomical abnormalities that may contribute to pulsatile tinnitus in 63% of patients.

CONCLUSIONS

In the absence of objective pulsatile tinnitus, MRI/MRA is an appropriate initial diagnostic step. When a patient has an objective bruit, the clinician may choose to proceed directly to angiography to make certain that a TS DAVF is not missed.

Pulsatile tinnitus--a review of 84 patients

Pulsatile tinnitus can be annoying for a patient and can also be the only clue to a potentially devastating and life-threatening disease. In order to understand its clinical spectrum and management better we analysed the files of 84 patients seen at our institution over a 10-year period. Noninvasive techniques (ultrasound, computed tomography, magnetic resonance imaging) and angiography were employed as investigations tailored to the individual patient. A vascular disorder [i.e. arteriovenous fistula, dissection of the internal carotid artery (ICA), fibromuscular dysplasia, aneurysm of the ICA and sinus thrombosis] was found in 36 patients (42%), most commonly a dural arteriovenous fistula or a carotid-cavernous sinus fistula. In 26 patients with a vascular abnormality, pulsatile tinnitus was the presenting symptom. In 12 patients (14%), nonvascular disorders such as glomus tumour or intracranial hypertension with a variety of causes explained the tinnitus. We conclude that patients with pulsatile tinnitus should be investigated with noninvasive techniques. If these are negative or to clarify abnormal findings of noninvasive techniques selective angiography is needed for diagnosis and to guide treatment.

Neurovascular decompression of the eighth cranial nerve in patients with hemifacial spasm and incidental tinnitus: an alternative way to study tinnitus

OBJECT

The authors sought to clarify the clinical characteristics of tinnitus resulting from neurovascular compression (NVC) of the eighth cranial nerve.

METHODS

The authors explored the eighth cranial nerve in the cerebellopontine cistern during neurovascular decompression (NVD) of the facial nerve in 10 patients with hemifacial spasm who suffered from incidental tinnitus on the same side. The diagnosis of NVC of the eighth cranial nerve was confirmed in all patients. This condition was found in only seven of 114 patients with hemifacial spasm alone, indicating that NVC of the eighth cranial nerve is one of the causes of tinnitus (p < 0.001, chi-square test). The tinnitus resolved or was markedly improved after NVD of the eighth cranial nerve in eight patients (80%). Both pulsatile and continuous tinnitus responded well to NVD. All patients experienced various degrees of sensorineural hearing disturbance, but other neurotological examinations provided poor diagnostic value.

CONCLUSIONS

It is the authors' opinion that sensorineural hearing loss and positive findings on magnetic resonance imaging are the most reliable evidence for the presence of tinnitus caused by NVC of the eighth cranial nerve.

Otologic manifestations of benign intracranial hypertension syndrome: diagnosis and management

Benign intracranial hypertension (BIH) is a syndrome characterized by increased intracranial pressure (IIP) without focal signs of neurological dysfunction. The diagnosis is essentially made by exclusion of various causes of IIP. The classic presenting symptoms of BIH are headache and/or visual disturbances. Otologic manifestations of this syndrome have not been described in detail. In this thesis, 20 BIH patients with associated otologic symptoms were thoroughly studied over a 5-year period. The author concludes that 1. objective pulsatile tinnitus and low frequency hearing loss can be the major or only manifestation of this syndrome; 2. diagnosis is established by lumbar puncture and elimination of other causes of IIP; 3. medical management is very effective with surgery reserved for patients with deteriorating vision or with disabling tinnitus.

Hemiparesis caused by vertebral artery compression of the medulla oblongata. Case report

The case is reported of a patient with progressive left hemiparesis due to vascular compression of the medulla oblongata. Metrizamide computerized tomography cisternography revealed that the left vertebral artery was compressing and distorting the left lateral surface of the medulla. Compression was surgically relieved and symptoms improved postoperatively. Neurological and symptomatic considerations are discussed in relation to the topographical anatomy of the lateral corticospinal tract.