Your vestibular nerve will be cut during surgery. This will result in zero balance function coming from the AN side. This sudden change (loss) of balance function is what brings about the symptoms of vertigo and dizzyness and nausea.
Right now, that particular vestibular nerve in your head is compromised by the tumor. The balance function on that side is less than 100%. The closer that level of function is to 100% at the time of surgery, the greater the sudden change (loss) in function when it is cut and brought to 0%.
So, if your vetibular nerve is already pretty bad off, the change from surgery will be relatively small and therefore your dizziness etc after surgery will be minimal since your brain is already adjusted to the low balance function on that side.
There are tests to see where the nerve is at in terms of function. It may be pointless to get a gentamicin injection if the function on that side is basically destroyed already.
Gentamicin destroys the function of the chochlea. The chochlea has two chambers, one for balance and one for hearing. There is a possibility that the injection could destroy the hearing section of the chochlea as well. If there is a chance of preserving your hearing through surgery, then find out the risk to your hearing that the injection could pose.
One way or other, your balance function will be gone on that side. If a gentamicin injection bringing this about before surgery will make recovery easier is dependent on your current level of function on that side. In my case, my Dr told me my balance function was pretty much gone and would slowly decline while I Watch and Wait, therefore, if and when I eventually get surgery, any dizziness etc would be minimal.
Gentamicin will kill that function and getting that out of the way may be a very good idea. The injection is a simple process. There is the risk to your hearing, but I don't know how much of a concern that is and you should find that out.
