Acoustic Neuroma

 

What Is Acoustic Neuroma? 

An acoustic neuroma is a tumor that grows from the nerves responsible for balance and hearing. More accurately called Vestibular Schwannoma, these tumors grow from the sheath covering the Vestibulocochlear Nerve.

Acoustic neuromas are benign (not cancer) and usually grow slowly. Over time the tumor can cause gradual hearing loss, ringing in the ear, and dizziness. Because of their slow growth, not all acoustic neuromas need to be treated. Treatment options include observation, surgery, and radiation.

 

 

Surgical removal is the most common treatment for Acoustic Neuromas:

CRANIOTOMY

• Suboccipital (retrosigmoid) craniotomy is made behind the ear in the occipital bone. Bone overlying the internal auditory canal is removed to expose and remove the tumor. This approach may be used for all tumor sizes, but especially large ones, while preserving facial nerve function and useful hearing if possible.
• Translabyrinthine craniotomy is made through the ear in the mastoid bone. The semicircular canals are removed to expose the tumor in the internal auditory canal. Because the canals are removed, complete hearing loss occurs in the affected ear. This approach may be used for patients who already have hearing loss or when preservation of hearing is not possible.
• Middle fossa craniotomy is made above the ear in the temporal bone. Bone overlying the internal auditory canal is removed to expose and remove the tumor. This approach may be used for small tumors and when preservation of hearing is optimal.

No surgery is without risk. General complications of any surgery include bleeding, infection, blood clots, and reactions to anesthesia. Specific complications related to a craniotomy may include stroke, seizures, venous sinus occlusion, swelling of the brain, and CSF leakage.

Risks related to acoustic neuroma surgery may include:

Facial weakness is the loss of muscle control on one side of the face caused by nerve swelling or damage; it may be temporary or permanent. Temporary facial paralysis or weakness is common after surgery and may persist for 6 to 12 months. Those with facial weakness will need to take extra care of their eye with artificial tears and lubricant until facial nerve function improves. Facial nerve function is directly related to the size of the tumor.

Eye problems may occur as the result of facial weakness or paralysis that prevents the eye from closing completely. This allows the eye to become dry and unprotected. Artificial tears, eye lubricants, protective glasses, bandage contact lenses, and taping the eye shut are all options to protect the cornea.

Hearing loss is the most common complication and may be permanent in the affected ear because the tumor is wrapped around the cochlear nerve. In small tumors it is possible to save hearing when removing the tumor. Larger tumors usually have already caused some hearing loss or deafness prior to surgery.

Balance problems are common and generally improve after surgery with head exercises, Pilates, or Tai Chi. Care should be taken when using stairs or escalators. Persistent balance or dizziness problems may need treatment with vestibular (balance) rehabilitation.

Cerebrospinal fluid (CSF) leakage is the escape of CSF that flows around the brain.

Headache is common after acoustic neuroma surgery and usually subsides within several weeks. Persistent headache (>3 months) can occur after suboccipital craniotomy.

 

RECOVERY AND PREVENTION

Coping with the possibility of hearing loss and facial paralysis and deciding which treatment is best for you can be difficult.

Hearing preservation is an important goal for patients with an acoustic neuroma, although it is not always possible.

Balance problems can be improved with exercise, Pilates, or Tai Chi. Dizziness is common and will persist until the opposite ear can compensate and stabilize, usually within 1 to 4 months. Persistent problems with balance, dizziness, or vertigo may require treatment with vestibular rehabilitation.

Facial exercises and massage are recommended to improve facial nerve function. If a patient has facial weakness after treatment, eye care consists of artificial tears and lubricant until facial nerve function returns. If a patient has facial paralysis 1 year after surgery, the chance of further recovery is reduced. Consultation with an ENT surgeon who specializes in facial plastic and reconstructive surgery is recommended.

Acoustic neuromas sometimes recur after radiation or surgery. Periodic MRI scans (every 1 to 3 years) and hearing tests are an important part of long-term monitoring.