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Treatment Options for Acoustic Neuromas
Tumor Excision by Microsurgery for Acoustic Neuroma
Suboccipital Approach - Following suboccipital or retrosigmoid surgery, hearing preservation is reported in up to 58% of patients regardless of tumor size. Facial nerve function preservation, however, is related to tumor size. If the tumor is small, up to 95% percent of patients retain facial nerve function at level I or II on the House-Brackmann grading scale. If the tumor is larger than 4 cm, however, the percentage drops to 38%.
Translabyrinthine Approach - The translabyrinthine approach sacrifices all hearing in the affected ear. The major advantage of this approach is the preservation of facial function. At one year post-surgery, one study showed that approximately 83% of patients maintained level I and II scores on the House-Brackmann scale. If the tumor was larger than 3 cm, level I and II function was noted in 52% of the patients. In a 5-year study using this approach, 70% of all patients had good facial nerve function. Another study following this surgery reported facial nerve preservation at 86%, facial paralysis at 31%, and delayed partial paresis (weakness) at 50%. At two years post-surgery, approximately 63% of patients were at the level I or II of the House-Brackmann scale for facial function.
You can read more about post-surgical preservation of hearing and facial function by clicking on the following links: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&listuids=12806302&queryhl=4&itool=pubmed_docsum
Postoperative headache, ranging in intensity from mild to severe, has been reported in approximately 33% of patients following acoustic neuroma surgery, though the range varies widely in the literature. Headaches usually resolve within 12 weeks but some patients experience persistent postoperative headaches for 1 year or longer. Most headaches resolve by 3 years post-surgery.
The risk of residual tumor following acoustic neuroma surgery is about 5-10% or less and is most commonly encountered following suboccipital surgery. This may be attributed to a small amount of tumor remaining in a section of the auditory canal which is very hard to visualize during surgery. Symptoms of recurring tumor may include headache, unusual facial sensation, or difficulty with speech pronunciation. Inflammation at the site from which the tumor was removed may persist and must be differentiated from recurrent tumor through MRI scans with gadolinium.
Complications of Acoustic Neuroma Surgery
After any type of microsurgery for excision of an acoustic neuroma, the patient typically will be observed for at least one night in the intensive care unit of the hospital. Patients may experience a range of immediate postoperative symptoms including headache, fatigue, nausea/vomiting, tinnitus, facial droop or palsy, balance problems, inability to close the eyes, or dryness of the eyes. The patient is typically discharged after 3-4 days. The total recovery time for surgical removal of an acoustic neuroma may take from 4 to 6 weeks or longer. After 3-6 months, an MRI may be ordered by the physician in order to visualize the site of the tumor for future reference. The MRI may be repeated at 5-10 years post-surgery.
