Daoisthere, great to see you doing your due diligence. Acoustic neuromas are one area where research is vital for the best outcome.
Interesting you should mention diabetes and acoustic neuromas. It would appear that diabetes is protective for acoustic neuroma growth!
“Tobacco use and diabetes demonstrate a protective effect, although the mechanism of this is poorly understood.” http://d-scholarship.pitt.edu/10555/1/Oren_B._ETD.pdf . I have more references, but I don’t have them handy at the moment.
The inner ear canal is where the vestibulocochlear nerve (cranial nerve VIII) and the facial nerve (cranial nerve VII) pass. The internal auditory canal also has the labyrinthine artery. I’m not sure what else is in the canal. The canal is within a bony surround.
Schwann cells do not cover the entire nerve. Instead the schwann cells cover each individual nerve fibre. There are thousands of nerve fibres per nerve, each carrying a separate piece of information. For example the cochlear branch of the vestibulocochlear nerve has 25,000 individual fibres, each carrying it’s own piece of information. In a vestibular schwannoma, the schwann cells overgrow. To get to the nerve fibre in question, other nerve fibres have to be damaged.
If you go for radiotherapy, radiation dose of to the tumor, cochlear and cochlear nucleas (located in the brainstem) are important. You need to keep the last two low.
With regards to experience, it is essential that the surgeon has personally done more than 100 vestibular schwannoma surgeries. How a surgeon goes from zero to 100 surgeries is an interesting topic.
I’ve been recently re-reading “Active Treatment is Not Indicated in the Majority of Patients Diagnosed with Vestibular Schwannoma: A review on the Natural History of Hearing and Tumor Growth”
https://www.bhtinformatie.nl/pdf/ingrijpen.pdf It provides a treatment strategy which is reproduced below.
Considering that only around one-third of small to medium-sized VS grows within 5 years after diagnosis and that very few tumors grow beyond this timeframe, the main argument in favor of primary active treatment (surgery or radiotherapy) is to preserve hearing function. However, reviews on published results of hearing preservation by both surgery and radiotherapy show that on average, around 50 % of patients preserve good or serviceable hearing short-term by both modalities. By observation, 60 % preserve good hearing after 5 years and if the discrimination is normal at diagnosis, as many as 75 % preserve good hearing after 10 years. In other words, all patients with a small or medium-sized tumor should be offered watch and wait management primarily, by repeated MRI scans. If growth occurs, active treatment is indicated.
However, some specialized centers may have documented considerably better than average results of active treatment, thus justifying primary active treatment. The use of novel and improved intra-operative neuro-monitoring equipment (see below) may also improve functional results considerably, thus leading to primary surgery as a reasonable option for optimal hearing preservation. In addition, other reasons for microsurgery may exist, e.g., otherwise intractable dizziness or physiological reasons, although these are generally rare.
On a global scale, more and more centers are adopting the strategy of primary observation of small and medium-sized tumors. As growth after diagnosis occurs within the very first few years in almost all cases, the following observation strategy by repeated MRI to assess tumor size is suggested (after diagnosis): 6 months, 1, 2, 3, 4, 5 years, and then every other year until 10 years. After 10 years, termination may be considered, as growth after this duration is very rare, but we suggest scan every 5 years, until 25 years, in order to collect long-term data. Again, if significant growth occurs during observation, active treatment is recommended. Continued observation may be continued if the tumor is still small, or in patients with significant co- morbidity. However, the patient should be informed, that continuing wait and scan management in the face of a growing tumor may increase the risk of morbidity from active treatment at a later date.Keep up the research. It’s very confusing at first, but after a few months it will all come together. Then you can make an informed decision.
