One of the seminal texts on the subject, “Fundamentals of Aerospace Medicine,” is a reference I frequently dive into with the many questions I have about the various medical conditions we discuss with members and how those conditions will affect their medical certification.
We can go for many months dealing with more common bread-and-butter issues including heart disease, cancer, renal disease, strokes, and of course, hypertension. One of the less common conditions that is a concern for pilots and for the FAA is acoustic neuroma. Also known as a “vestibular schwannoma,” it is a noncancerous and slow growing tumor that presents on the main nerve, the vestibular nerve that connects the inner ear to the brain. This nerve pathway is an important one that directly influences balance and hearing, both important senses that we can all agree need to be working “nominally” not only when we’re in direct contact with terra firma, but also when surrounded by nothing but air around us.
Being as acoustic neuromas are slow growing, we can have one for many years and not even know it until it reaches a size that begins to produce subtle or not so subtle symptoms. Hearing loss is often a first indication of something going on, but again, the loss may be so gradual that the person may not really notice anything until a friend or loved one begins to notice something going on and you start to hear them repeating in a not so normal conversational tone, “Did you hear me?!”
Tinnitus, or ringing in the ears, is another presenting symptom, although tinnitus can be a symptom of a number of conditions. Dizziness usually gets everyone’s attention and, if it persists, can be a strong motivation to get thee to a doctor. Diagnosis can sometimes take a while, but a good first step is to have your hearing tested through audiometry. The audiologist doing the test will project a range of sounds of different tones into each ear separately at different levels to detect the faintest sound you can hear.
Imaging using MRI or CT can narrow down the potential culprit and detect tumors only millimeters in size. If a neuroma is diagnosed, treatment options include just monitoring with periodic imaging to check on growth, or, if the tumor continues to grow or becomes symptomatic, surgical intervention, or radiation therapy. Radiation therapy often includes a procedure called stereotactic radiosurgery for small tumors. Also known as Gamma Knife radiosurgery, it is a process during which tiny gamma rays are used to direct a precisely targeted radiation dose to the tumor without damaging surrounding structures.
From the FAA perspective, medical certification following a diagnosis and/or treatment for acoustic neuroma is likely if there is evidence of good recovery without significant adverse post-treatment complications. The acoustic neuroma Disposition Table provides guidance to your aviation medical examiner about issuing a medical certificate at the time of the exam. If treatment with surgery or stereotactic radiation was completed more than five years previously, and there are no symptoms, the AME may issue the exam. Otherwise, the application will be deferred to the FAA for review and will result in a special issuance authorization. As always, the FAA requires thorough records including diagnostic reports, treatment plan, surgical report, and favorable follow-up status reports. The authorization will probably be in effect for several years with annual follow-up reports to the FAA.