Skull Base Surgery
Neurotology is a medical subspecialty of otolaryngology, or the care of ear, nose, throat and neck conditions. Within this field, neurotologists have extra training that focuses on the diagnosis and treatment of disorders affecting the ears, skull base, temporal bone and balance as well as the anatomy of the head and neck.
Most of the conditions related to neurotology are benign, but occasionally a malignancy is involved. In addition to tumors, neurotology may treat chronic infections, inflammation or other issues that can result in hearing loss and the development of a vestibular disorder. The field includes both medical and surgical management techniques for the care of a wide variety of health issues, such as acoustic neuromas, meningiomas, glomus tumors, Meniere’s disease, facial nerve disorders, encephalocele and more.
Also known as a vestibular schwannoma, an acoustic neruoma is a benign tumor found in the nerves that lead from the brain to the inner ear and control balance and hearing. This common brain tumor is usually slow-growing and does not affect brain tissue like cancerous tumors do. Many patients do not experience any problems from this type of tumor since it can remain very small.
The cause of an acoustic neuroma is unknown, although it may be associated with a rare condition called neurofibromatosis type 2, a genetic disorder that affects the same nerves. Other acoustic neuromas may be related to exposure to head and neck radiation. Most patients who develop this type of tumor are between the ages of 30 and 60 years old.
Patients with an acoustic neuroma may experience hearing loss as a result of the tumor placing pressure on the nerve, dizziness, ringing in the ears, loss of balance and facial numbness and weakness. If left untreated, an acoustic neuroma can lead to permanent hearing loss and a buildup of fluid within the head.
Treatment for an acoustic neuroma depends on the size and growth rate of the tumor, and may include observation, radiation or surgical removal. Small tumors can be monitored regularly through imaging and hearing tests to determine how fast and how much it is growing. Radiosurgery delivers radiation therapy to the tumor to stop it from growing without the need for an incision and is most often used for tumors that cannot be removed without damaging brain tissue. Larger tumors may be removed through surgery to prevent permanent damage from occurring.
Temporal Bone Encephalocele
Encephalocele is usually caused by a congenital birth defect involving an incomplete closure of the neural tube. During normal fetal development, the neural tube closes as the brain and spinal cord grow. However, if it does not close correctly, an encephalocele forms in a sac containing brain tissue and cerebrospinal fluid and protrudes through an opening in the skull. It may emerge at the base of the skull into the mastoid bone. Encephalocele is often accompanied by brain and nervous system issues.
Treatment for encephalocele requires surgery. A surgical procedure is the only way to effectively reposition the brain matter and seal the skull opening. A small portion of the skull bone will be cut out and an incision is made in the dura, the membrane covering of the brain. The doctor will then remove the sac around the encephalocele and shift the brain and fluid back into place. Finally, the dura is sutured closed and the skull bone is replaced. In some cases, an artificial plate is used to repair the skull or a shunt is inserted to drain excess fluid.
Facial paralysis involves a loss of voluntary muscle movement within the face, which may occur as a result of stroke, brain tumor, infection, trauma, Bell’s palsy or other factors. The facial nerve stretches down each side of the face and allows us to laugh, cry, smile or frown when functioning properly. Patients with facial paralysis may experience symptoms such as:
- Drooping of the face
- Difficulty making facial expressions
- Loss of taste
ENoG testing is performed to obtain information about facial nerve functioning.
Treatment for facial paralysis depends on the underlying cause of the condition, but may include medication, physical therapy or surgery to relieve pressure on the facial nerve or to repair a severely damaged facial nerve.
A glomus tumor is a growth in the temporal bone, located on the skull near the ear. It forms within the jugular foramen, which is the portion of the temporal bone that the jugular vein and a number of nerves run through. The nerve fibers present, known as glomus bodies, are involved in the body’s temperature and blood pressure regulation. Usually benign, glomus tumors are most common in older individuals, but can develop at any age. There are no known causes or specific risk factors.
The typical symptoms of a glomus tumor include having trouble swallowing, hearing loss, dizziness, pulsing tinnitus, a hoarse voice, pain and facial muscle weakness or paralysis. To diagnose a glomus tumor, a physician will conduct an examination of the area and perform testing that may include a CT or MRI scan and a cerebral angiography.
Treatment for a glomus tumor generally involves surgery to remove the mass. If the entire tumor cannot be removed surgically, radiation may be needed to shrink the remaining tissue. Depending on the location and size of the tumor, a form of radiation therapy called stereotactic radiosurgery may be a more effective treatment than surgery in some cases for gaining access to the tumor.