At the Barrow Neurological Institute, a team approach is used for the treatment of acoustic neuromas. The types of physicians involved in a patient's treatment depend on the course of treatment that is needed.
Teams from neurotology, neurosurgery, neurology, radiation therapy, ophthalmology and plastic surgery (all physicians) and other team members discuss each individual patient's situation and recommend a treatment plan for the patient to consider. The Barrow Acoustic Neuroma Center utilizes the team approach to provide state of the art treatment of acoustic neuromas.
Treatment Options for Acoustic Neuroma
Treatment options for acoustic neuromas include:
- Observation and monitoring
- Stereotactic radiation therapy
Older patients with small, non-growing tumors can be monitored safely and MRI scanning repeated over a period of time. If and when tumor growth is confirmed, other treatment options can be considered. Continued observation and monitoring is also indicated for patients who have undergone treatment with stereotactic radiation.
The choice of treatment depends on several factors:
- patient's age and overall health
- level of hearing in both ears
- size of the tumor
The treatment choice is a decision made by the patient after extensive discussion with members of the Barrow Acoustic Neuroma Center (BANC) team. View the treatment evaluation process.
Stereotactic radiosurgery uses precisely focused beams of radiation to obliterate unhealthy tissue in the brain. Based on a large number of patients treated with stereotactic radiation, this method has proven to be a suitable option for certain patients with acoustic neuromas.
The Gamma Knife and CyberKnife are both effective methods of delivering stereotactic radiation therapy. The Gamma Knife delivers a single, high dose of ionizing radiation by exactly pinpointing the target, utilizing advanced imaging. Isodose curves for a left-sided acoustic neuroma. The critical structure, the brain stem, is outlined, with the target is shown. The direction of the beams in shown in the lower right hand corner.
One advantage of stereotactic radiosurgery as a treatment option is that the risk of standard surgical complications can be eliminated. The risk of hearing deterioration is approximately 25%, and facial weakness averaging less than 1%. The risk of malignant transformation (the benign tumor changing into a cancerous lesion as a result of exposure to radiation) is close to non-existent.
Fractionated stereotactic radiation therapy is an attractive option now available at Barrow with the CyberKnife treatment system. The CyberKnife does not require use of an invasive, stereotactic frame. Therefore, it permits fractionated treatments: lesions often unsafe to treat with single-session radiosurgery can be treated over several sessions with lower prescribed doses. When radiation is delivered over three to five sessions, there is evidence that damage to the cochlear (hearing) nerve often is reduced, thus the chance of hearing preservation can be greater than with single treatment.
The main indicator of acoustic neuroma treatment success is lack of tumor growth, or in some cases, shrinkage of the tumor or conversion to scar tissue. Because the tumor is not removed with stereotactic radiosurgery, long-term follow-up with repeated MR imaging over a period of time is required.
Surgical Approach to Acoustic Neuroma Treatment
Typically, acoustic neuroma patients are first evaluated by a neurotologist and are then referred to the neurosurgeon for further discussion about surgery. There are multiple surgical approaches available to remove the tumor. Our center has modified many established surgical procedures and developed new surgical approaches to access tumors in the cerebellopontine region.
One of the following approaches to treatment of acoustic neuroma is frequently utilized at Barrow:
- Transcochlear approach
- Translabyrinthine approach
- Retrolabyrinthine approach
- Far Lateral approach
- Combined approach
- Middle fossa approach
- Retrosigmoid approach
The recommended surgical approach is discussed with the patient in detail after all the factors have been considered. The risks, potential complications, and outcomes (both short-term and long-term) are discussed with the patient and family/support person(s).
Middle Fossa Approach for Acoustic Neuroma Treatment
Middle Fossa Approach for Acoustic Neuroma Treatment
The middle fossa approach in the treatment of acoustic neuroma is completed through a temporal craniotomy in front of the ear. The surgeons then elevate the brain and drill the bone over the top of the tumor and nerves. The main benefit is that there is a very good chance at hearing preservation. The disadvantage is its usefulness for smaller tumors and it may carry a slightly higher risk of facial weakness.
The translabyrinthine approach in the treatment of acoustic neuroma is performed through a "C" shaped incision behind the ear. The bone in front of the sigmoid sinus is drilled out, and then the semicircular canals are drilled to expose the most lateral extent of the tumor. The semicircular canals are small fluid filled tubes encased in bone that assists with balance function. The hearing is sacrificed in the translabyrinthine approach so it is ideally suited for those patients who are deaf or have no hearing in the affected ear.
There is no limitation of tumor size with this approach. The main advantage is that the facial nerve is identified early in the operation increasing the likelihood of preserving good or normal facial function post-operatively. The disadvantage is that there is a slightly higher chance of spinal fluid leakage, hearing is sacrificed and a small incision is required in the abdomen to harvest fat used to pack in the defect at the end of surgery.
Retrosigmoid Approach for Acoustic Neuroma Treatment
The retrosigmoid approach in the treatment of acoustic neuroma is done through an incision behind the ear. The bone over the sigmoid sinus is drilled. The sigmoid sinus is a large vein encased in the bone behind the ear. The advantage to this approach includes the absence of size limitation; increase of hearing preservation and the risk of spinal fluid leakage is low. The disadvantage of this approach is that if the tumor extends far laterally out the internal auditory canal, complete removal can be difficult. The facial nerve is out of the surgeon's view. This may increase the risk of facial weakness post-operatively.
How can we help you?
For more information or to make an appointment, please call 1-800-BARROW1 (227-7691) or 602-406-6281.