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Advantages of the suboccipital approach include:

• Possibility of hearing preservation
• Tumors of all sizes can be removed

Some of the difficulties involved with this surgical approach include:

• May carry a higher risk of cerebrospinal fluid leakage
• May be associated with a higher rate of long-lasting postoperative headaches. It is thought that this may be due to bone dust which may enter the spinal fluid space during drilling.
• May be associated with a higher risk of tumor recurrence than other surgical approaches
• May require manipulation of the cerebellum during surgery
• Facial nerve preservation appears to correlate with tumor size

Translabyrinthine Approach

The translabyrinthine approach for acoustic neuroma surgery is typically considered only if hearing preservation is not an objective due to poor preoperative hearing levels. The translabyrinthine approach may be used to remove tumors of any size including those that are large with significant extension of the tumor into the cerebellopontine angle. The translabyrinthine approach is the most direct approach to access the cerebellopontine angle. An incision is made behind the patient's ear. The mastoid bone and some parts the inner ear (semicircular canals) are removed which provides easier access to the internal auditory canal and the cerebellopontine angle. The translabyrinthine approach rarely involves the manipulation of the brainstem, thereby reducing associated risks and it provides good visibility of the side of the brain that faces the tumor. A benefit of this approach is that it makes it easy for the surgeon to locate the facial nerve in the temporal bone before the tumor is removed, thus increasing the surgeon's chances of preserving facial nerve function. Unfortunately, hearing is always sacrificed with this approach.

Advantages of the translabyrinthine approach include:

• Tumors of all sizes can be visualized and removed
• No part of the brain needs to be manipulated
• Good preservation of facial nerve function

The major disadvantage of this surgery is:

• There is always a complete loss of hearing on the operated side
• Some portions of the cerebellopontine angle and cranial nerves are not well visualized
• A fat graft is required where fat is surgically removed from the abdomen and grafted to the site of the incision.

Efficacy of Surgical Treatment and Prognosis

The control rate (rate of tumor recurrence) of all three surgical approaches is similar. Complete removal of acoustic neuromas is achieved in 95% of patients. Because there is a small chance that the tumor will come back again, the health care provider will typically order a follow-up MRI within 1 to 5 years. The NIH Consensus Statement noted that follow-up visits may take place every three months following surgery to every 1-2 years as the duration from the time of surgery increases, depending on the clinical presentation of the patient. Mortality rate following surgery is less than 1%. It is important to note that the successful outcome of surgery for acoustic neuromas continues to improve as surgical techniques and equipment become more sophisticated and precise. For this reason, it is very important to choose a neurosurgeon who has extensive experience with the surgical approach to be performed and to ask the surgeon about their rate of success and incidence of complications. There are differing opinions regarding the degree to which intraoperative monitoring of the auditory nerve accurately predicts hearing preservation. While in select groups of patients 80% hearing preservation has been reported, overall approximately 50% of patients retain functional hearing in the affected ear following surgical excision. There have been only a few reports of patients experiencing an improvement in hearing following acoustic neuroma microsurgery. It is believed that removal of the tumor and subsequent decompression of the cochlear nerve may explain any improvement in hearing. Regarding the stability of long term hearing following surgery, results of studies are mixed and inconclusive.