Acoustic Neuroma (Vestibular Schwannoma)
An acoustic neuroma (more appropriately known as a vestibular schwannoma) is a benign (non-cancerous) tumor that originates from the vestibulocochlear (eighth cranial) nerve. This nerve normally transmits sound and balance information from the inner ear to the brain. Acoustic neuromas are uncommon, with an incidence of nine to thirteen per million people per year and typically occur on just one side. Neurofibromatosis Type 2, a rare genetic disease, is the exception in that patients afflicted with this condition often have acoustic neuromas on both sides.
Acoustic neuromas are usually slow growing and may not cause symptoms at first. As the tumor increases in size (typically one to two millimeters per year) and compresses surrounding nerves, sensorineural hearing loss, tinnitus and vertigo (feeling that the world is spinning when you are not moving) may develop. Headaches, vision problems, facial weakness and sensory abnormalities of the face can occur with larger tumors.
Evaluation of acoustic neuroma involves a complete medical history and examination of the ear as well as several diagnostic tests. Our practice typically obtains a comprehensive audiogram to assess hearing and MRI scans of the brain with fine cuts through the internal auditory canal to accurately determine the tumor’s size. Other tests such as videonystagmography (VNG) to evaluate horizontal semicircular canal/superior vestibular nerve function, vestibular evoked myogenic potentials (VEMP) to assess saccule/inferior vestibular nerve function and high-resolution temporal bone CT scans (to evaluate mastoid development and height of the jugular fossa) may be ordered as well.
Because acoustic neuromas are typically slow growing and non-cancerous, observation using serial MRI scans (every 6 – 12 months) is an option if tumors are small and not causing any neurological symptoms. If treatment is required, surgery and radiation are available options. The primary goal of surgery is to remove the tumor, with preservation of hearing and facial nerve function when possible. Surgery is complex and requires a team of surgeons, including a neurotologist and neurosurgeon. Radiation using stereotactic delivery devices is also available at the Center for Neurosciences. Stereotactic radiosurgery directs beams of radiation to the tumor without making any incisions. The goal of radiosurgery is to stop the growth of the tumor, but the tumor is not removed. It requires lifelong surveillance using MRI scans since tumors may regrow at a later date. Rarely, malignant transformation (formation of a new cancer at the radiation site) has also been reported.
Why Choose Us
- Dr. Abraham Jacob, Medical Director for Ear & Hearing (E&H) at the Center for Neurosciences (CNS), is fellowship trained in Otology, Neurotology, and Cranial Base Surgery. His fellowship was with Dr. Brad Welling, former ENT Chair at Ohio State and now Chair of the Harvard ENT program. Dr. Jacob is the first and most experienced Neurotologist in Tucson.
- Dr. Jacob was a founding member of the University of Arizona (UA) Department of Otolaryngology and founding Director of the UA Ear Institute prior to his departure and transition to CNS. At UA, he was Vice Chair of ENT and held the rank of full Professor with Tenure. He has an international reputation as an expert for treating ear diseases.
- Dr. Jacob transitioned his practice to the Center for Neurosciences in early 2017 as he felt that the new environment helped him to optimize delivery of personalized ear and lateral skull base care for his patients.
- Dr. Abraham Jacob’s specific expertise as a temporal bone, skull-base surgeon is supported by an extensive clinical infrastructure at the Center for Neurosciences and the Tucson Medical Center, including tertiary care operating rooms, neurosurgery support, neuroradiology support, and a neuro/critical care ICU.
- Dr. Jacob has published dozens of papers on temporal bone surgery, including surgery for acoustic neuromas. In partnership with Neurosurgery, he is able to perform translabyrinthine, middle fossa, and retrosigmoid approaches to these tumors. Dr. Jacob has presented cutting-edge research on the pathobiology of vestibular schwannomas at both national and international meetings. When involved in basic science research during his time at Ohio State and UA, he received over 1.5 million dollars of extramural grant funding to study the behavior and treatment of these tumors.