Surgery for Vertigo - Clinical Tree

Surgery for vertigo is typically a treatment of last resort, whether due to a peripheral or central etiology. The vast majority of patients may be managed conservatively with medical treatment and/or vestibular rehabilitation therapy. Critical to the management of patients with vertigo is the correct diagnosis of the underlying pathology. The small percentage of patients who fail maximal medical management may benefit from surgery. It is imperative that the correct side is also identified. Surgical options include those that address the specific pathology of the disease, as well as those that ablate the peripheral vestibule or organ. This chapter describes operative techniques for posterior semicircular canal (PSC) occlusion; endolymphatic sac decompression, with or without shunting; labyrinthectomy; vestibular nerve section; and vascular loop decompression. Repair of superior canal dehiscence (SSCD) and treatment for acoustic neuroma are discussed in Chapter 149, Chapter 142 , respectively.

Key Operative Learning Points

1.
Surgery is indicated only for control of disabling vestibular symptoms in patients with peripheral or central vestibulopathy with failed maximal medical treatment and vestibular rehabilitation.
2.
Vestibular ablation is typically contraindicated in those patients with bilateral peripheral or central vestibulopathy.
3.
The retro sigmoid and retromastoid are the preferred approaches for vestibular nerve section in patients with aidable hearing in the affected ear.
4.
The PSC should be fenestrated midway between the ampulla and the common crus for PSC occlusion to minimize the risk of violating the vestibule and causing sensorineural hearing loss ( Fig. 146.1 ).
5.
Ablation of the vestibular inner ear in the presence of bilateral peripheral vestibulopathy may result in disabling oscillopsia.
6.
Suctioning in the vicinity of a fenestrated or dehiscent semicircular canal may result in disruption of the membranous labyrinth and cause postoperative sensorineural hearing loss.
7.
Incomplete removal of the sensorineural epithelium within the PSC ampulla is the most common cause of persistent vertigo following labyrinthectomy.

Preoperative Period

History

Determine the frequency, duration, sidedness, symptoms, and length of time affecting the patient to help make the diagnosis.
History of migraines, motion intolerance, family history, and visual disturbances should be elicited.
History of seizures should be asked as well as cardiovascular disease.
History of trauma should be assessed.
Current and past medications should be assessed.
Tinnitus is non-specific unless characterized as being pulsatile. The evaluation should include glomus tumor, dural AV arteriovenous malformations, meningoceles, SSCD superior semicircular canal dehiscence, aneurysms, vascular loops, and dehiscent high riding jugular bulb.

Physical Examination

Office vestibular testing can usually evaluate benign positional vertigo (BPPV), hypoactive systems, vestibular ocular reflex (VOR) pathology, perilymph fistula, and acute vertiginous attacks.
Postural hypotension may be important to eliminate.
Pneumotoscopy should not cause vertigo or nystagmus. If present, consider perilymphatic fistula (PLF) or possibly SSCD.

Audiogram

Early Meniere syndrome typically manifests low-frequency sensorineural hearing loss on the affected side. Progression of disease results in a greater flat SNHL sensorineural hearing loss.
SSCD may demonstrate a conductive loss due to the third window effect, and loud noise may cause “dizziness” (Tullio phenomenon).
Labyrinthectomy may be offered to those with severe to profound SNHL. Caution and informed consent should be provided to patients with functional hearing who are offered intratympanic gentamicin therapy. Up to 30% of patients may experience further hearing loss following gentamicin injections.

Vestibular Testing

Videonystagmography (VNG) can be useful in identifying the “weak” side or bilateral weakness. Identifying bilateral weakness is important as it may preclude vestibular ablation surgery.
Vestibular evoked myogenic potential (VEMP) testing can be useful in identifying SSCD or indicate the side of the lesion.
Dix-Hallpike maneuver is used to make the diagnosis of BPPV.

Imaging

Magnetic resonance imaging (MRI) with gadolinium is important to assess for central lesions or inflammation of the vestibular nerve(s) or cranial nerves.
Computed tomography (CT) of the temporal bone in the coronal plane best highlights the SSCD (see Chapter 149 ).

Consultation With

Cardiology may be indicated to evaluate for arrhythmias (Holter monitoring), autonomic dysfunction (tilt table testing), or other abnormalities.
Neurology may be indicated for evaluation for a central etiology including headaches, seizures, and TIAs transient ischemic attacks.
Psychiatry may be especially beneficial as many of these patients may suffer from depression or anxiety.

Indications

BPPV–Posterior Canal Plugging

Offer surgery only after particle repositioning maneuvers by trained therapists or MDs Meniere’s disease fail to control symptoms that significantly affect the life of the patient. Less than 1% of patients require surgical intervention.
Surgical success rates are over 90%.
Must ensure the proper canal has been identified prior to surgery

Contraindications

Surgery in the elderly carries the potential development of vestibulitis, which can incur the unintended consequence of severe disequilibrium. This more chronic disorder is worse than the BPPV. The elderly with dysfunction of the inner ear are more prone to repeated falls and fractures.

Do not operate if the affected ear is the only hearing ear.

Preoperative Preparation

Verify that the planned operative procedure is being done on the identified malfunctioning semicircular canal.
Document hearing levels.
Document that a VNG was performed and rotary chair testing, if available, is obtained.
Explain the risks and ensure realistic expectations, including that disequilibrium may occur after the surgery.
Review imaging to ensure that no other pathology is present as the source for unrelenting positional vertigo.

Operative Period

Anesthesia

General anesthesia is preferred, and the patient should not be paralyzed during the operative procedure so that cranial nerve 7, as well as other cranial nerves, can be monitored if the need arises.

Positioning

The patient is turned 180 degrees from anesthesia so that the surgeon is on the side of ear to be operated and the scrub nurse on the opposite side with the microscope at the head of the table.
For the suboccipital or retrosigmoid approach the patient is typically put in neurosurgical pins and a Mayfield holder. Depending on the ability to turn the neck, an ipsilateral shoulder and hip bolster may help in providing access.

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Introduction