I am having a retrosigmoid approach, and the way understand it, the neurosurgeon will do the approach to the tumor and removal of the tumor from the vestibulocochlear nerve (hearing and balance nerve) in the area of the brainstem and pons. The neurotologist will drill into the auditory canal to get the rest of the tumor from that region. The neurotologists are specialists in surgery of the ear, which goes deep into your head and is housed in the temporal bone, that is, the outer,middle, and inner ear. Whereas, the neurosurgeon specializes in surgery of the brain and nerves. I would recommend looking at the anatomy of the ear and cranial nerves as it relates to acoustic neuromas. There is a wealth of info on-line to check out. Cleveland Clinic has a nice website with good pictures to help you understand.
Somebody please correct me if I have this wrong.
Jan