Acoustic Neuroma

I had an acoustic neuroma excision 20 years ago. As an active snorkeler I am well aware of barotrauma risks, and fortunately I have no problem equalising my middle ear since the Eustachian tube is functional on that side. I am deaf in that ear, however, and understand the risk of hearing loss on my good side. Are there any dive-related risks besides hearing loss?

A: Acoustic neuromas are distinctive and usually benign growths of cells of the eighth cranial nerve. Essentially a brain tumor that develops within the adjacent structures of the brain, it grows into a round mass on the nerve where it emerges from the acoustic canal. Although some acoustic neuromas may produce noticeable symptoms, many are undetected until their growth begins to affect the brain stem and produce symptoms of partial or complete nerve deafness. Their advanced growth tends to affect the fifth and seventh cranial nerves and cause cerebellar ataxia and ultimately brain stem dysfunction. Fortunately, micro-surgical techniques offer good results and can generally preserve the seventh cranial nerve and occasionally the patient's hearing.

When considering diving, there are several issues to address: preexisting partial deafness and the risk of complete hearing loss due to barotrauma, physical or functional impairments that may interfere with the ability to respond to an emergency, and the difficulty for a physician to diagnose possible decompression illness. Patients are at risk for cerebrospinal fluid leaks, a relatively common complication that even without diving can produce symptoms of nausea and vomiting, neck stiffness and a sense of imbalance. In addition to unilateral hearing loss, they almost certainly cause disabling symptoms of unilateral vestibular loss (e.g., persistent dizziness, gait disturbances and imbalance). Additionally, temperature changes encountered during a dive (not necessarily thermoclines) may induce a caloric response of disabling vertigo as well as nausea and vomiting due to asymmetrical vestibular stimulation. In general, physicians trained in dive medicine recommend that patients avoid diving after acoustic neuroma surgery, regardless of the surgical approach.
— Daniel A. Nord, EMT-P, CHT
© Alert Diver — Q2 2020