The neurosurgeons at the USC Minimally Invasive Neurosurgery and Endoscopic Skull Base Center have developed extensive experience with the diagnosis and evaluation of all tumors that affect the skull base. Endoscopic neurosurgery is a rapidly evolving subspecialty that takes full advantage of the most recent advancements in optical and video technology as well as surgical instrumentation to treat a variety of brain tumors and other conditions.
In endoscopic neurosurgery, small incisions and natural openings in the skull are used to safely and adequately perform a given operation. Using natural pathways and smaller incisions to approach various brain regions results in decreased injury to the brain, reduced risks of cerebrospinal fluid leakage, and may minimize pain, risk of infection and the length of hospital stays. Integration of advanced technology, including high quality endoscopy systems and high definition viewing monitors, into many types of neurosurgery has significantly improved our ability to perform many of these approaches on a daily basis.
We offer a comprehensive multidisciplinary skull base neurosurgical program, which allows treatment by experts from several specialties at the same time. This includes a neurosurgeon, neuro-oncologist, endocrinologist, radiation oncologist and ophthalmologist, among others. To streamline care and improve consensus among all physicians, patients’ cases are discussed at a weekly tumor board, where specialists from all these disciplines come together to formulate a cohesive plan for optimizing patient care.
Some of our innovative technology includes:
- BrainPath® – the BrainPath® is an innovative tool used to surgically operate on deep brain tumors and deep vascular lesions, including intracerebral hemorrhages, without causing injury to healthy brain tissue. The tool allows neurosurgeons to reposition healthy brain tissue when locating a tumor or lesion, instead of cutting it, lowering the risk of complications.
- Neuro-endoscopy – fueled by recent advances in optical technology and miniaturization of camera and digital devices, we are now able to explore and treat conditions located within small and complex spaces with unparalleled visualization and illumination.
- Neuro-navigation – intraoperative neuro-navigation pertains to the use of high-quality neuroimaging (such as an MRI) that is programmed into a specialized computer located within the operating room and registered to the patient’s surface anatomy prior to starting the operation. The navigation device acts as a sort of global positioning satellite, or “GPS,” for the brain that may improve safety and minimizes the size of surgical incisions.
- Minimally invasive instruments and design – specialized instruments for endoscopic microdissection are routinely used to remove tumors during operations performed at Keck Medical Center of USC.
Keck Medicine of USC offers the most advanced neurosurgical techniques for safely removing these tumors. Our neurosurgeons are fellowship-trained in minimally invasive endoscopic skull base surgery. Working with endocrinologists both in the community and at Keck Medical Center of USC, a large number of patients have been successfully managed by nonoperative strategies. Several types of radiosurgery are available for treating these tumors, including Gamma Knife®, among others. For more information on radiosurgery treatments, click here to visit the Stereotactic Radiosurgery Center.
Conditions treated in the USC Minimally Invasive Neurosurgery and Endoscopic Skull Base Center include:
Acoustic Neuromas, also called vestibular schwannomas, are benign, usually slow growing tumors that arise from the balance or hearing nerve (eighth cranial nerve) and do not spread to other parts of the body. Signs and symptoms of an acoustic neuroma include hearing loss, tinnitus or ringing in the ear and balance problems. As they get larger, these tumors can produce other symptoms including headaches, unilateral facial numbness and tingling, unilateral facial weakness, and fullness in the ear.
Visit the USC Acoustic Neuroma Center website for more information.
Chordomas are tumors that can occur anywhere along the spine. Most often they are found at the top of the spine (skull base or clival) or at the base of the spine (sacral). They are less frequently found in the neck (cervical), upper back (thoracic) or lower back (lumbar). These tumors are typically slow growing but can become aggressive in some cases.
Visit the USC Chordoma Center for more information.
A chondrosarcoma is a malignant bone tumor that tends to arise at the base of the skull, especially in the area near the pituitary gland.
A craniopharyngioma is a benign, yet locally invasive tumor typically located in the area of the pituitary gland. It is usually a hard tumor that can be calcified and is a remnant of a duct that develops between the brain (cranio) and mouth (pharynx). Its composition is frequently similar to that of tooth enamel. It often grows in intimate contact with surrounding structures, such as the pituitary stalk and gland, optic nerves, ventricles of the brain and blood vessels. Patients with craniopharyngiomas often present with visual loss, hormonal dysfunction, headaches, memory loss or confusion and pressure build-up in the brain (hydrocephalus).
An astrocytoma is a brain tumor made up of astrocytes, which are glial cells that support the neurons of the brain. Astrocytomas are the most common type of primary brain tumors originating from brain tissue. Even the most aggressive astrocytomas almost never spread throughout the blood and lymphatic systems into other parts of the body, and in this sense, they differ from cancers in that they typically remain confined to the central nervous system.
Hydrocephalus is a buildup of fluid inside the skull that leads to brain swelling. Hydrocephalus means “water on the brain.” Hydrocephalus is due to a problem with the flow of the fluid that surrounds the brain. This fluid is called the cerebrospinal fluid, or CSF. The fluid surrounds the brain and spinal cord, and helps cushion the brain. CSF normally moves through the brain and the spinal cord, and is soaked into the bloodstream. Too much CSF puts pressure on the brain. This pushes the brain up against the skull and damages brain tissue.
A meningioma is a slow growing, usually benign tumor of the brain or spinal cord. Although these tumors usually arise from the covering of the brain (meninges) and not the brain tissue itself, they often compress the brain and other important nerves or blood vessels. Approximately 98 percent of all meningiomas are benign, with the small minority being classified as “atypical” or “malignant.”
Metastatic Brain Tumors
Metastatic brain tumors are tumors that spread to the brain from another (primary) cancer in the body and are known to occur in 20 to 45 percent of cancer patients. Tumor cells often spread through the bloodstream or other routes across the blood-brain barrier (BBB) and into the central nervous system. In a minority of cases, the first presentation of a bodily cancer will be from a metastatic brain tumor. The most common primary cancers resulting in brain metastases that require treatment include lung, breast, melanoma (skin) and genitourinary tract cancers.
A pituitary adenoma is a slow growing and typically benign tumor arising from cells in the pituitary gland. Because they originate from cells in the pituitary gland, which is the master hormone gland, they often cause problems related to hormonal dysfunction. Some pituitary tumors result in excessive production and over-secretion of hormones, which can result in a variety of syndromes. A large proportion of these tumors, however, do not produce any functional hormones, but instead grow to a size where they cause symptoms because they compress surrounding structures. For these reasons, larger pituitary tumors (called macroadenomas) often present with headache, visual loss and pituitary gland dysfunction. Changes in energy level, sexual function and libido, and many other symptoms may be a result of a dysfunctional pituitary gland (called hypopituitarism). The overwhelming majority of pituitary tumors are benign with a minority being classified as “atypical” or “malignant.”
Rathke’s cleft cyst
Rathke’s cleft cyst is a benign cyst in the pituitary gland. It develops in the space between the front and back of the pituitary gland. Rathke’s cleft cysts may not cause symptoms. If larger in size, patients may experience symptoms as the cyst compresses surrounding areas of the brain.
Symptoms may include partial or total vision loss, blurry vision and hormone insufficiencies in the pituitary gland.
A colloid cyst is a benign tumor usually located near the center of the brain. Colloid cysts are slow growing. When symptomatic, colloid cysts may cause memory problems, headaches and confusion.
Epidermoid and dermoid tumors most likely form during fetal development. Symptoms may be present later in life. Epidermoid tumors are generally located where the brain stem and top of the brain meet. Dermoid tumors are found in the lower end of the spine in older children and rarely, in the lower part of the brain in older adults.
An arachnoid cyst is a fluid-filled sac in the subarachnoid area of the brain. Though typically asymptomatic, arachnoid cyst symptoms may include headache, nausea and vomiting, hydrocephalus and seizures.
Brain tumors in the area of the skull base may be treated with multiple treatment options. Treatment for each patient varies on each patient’s specific case, but may include observation, medical treatment, surgery, and radiation or radiosurgery.
Neuro-endoscopic surgical approaches are generally classified into the following categories based on how the endoscope is used during the operation:
Endoscopic endonasal pituitary and skull base surgery
These minimally–invasive procedures are used to treat a variety of tumors and other lesions arising at the base of the skull and in the paranasal sinuses. These operations are typically performed through the nostrils and are therefore called “endonasal” procedures. No incisions are made on the face and the recovery is typically quite rapid. Depending on the tumor, the operation may be performed by one surgeon or a team of surgeons (typically a neurosurgeon and otolaryngologist). In some cases, a small additional incision is made in the abdomen or thigh in order to remove a small piece of fat or fascia used to reconstruct the skull base and prevent fluid leakage following the operation. This approach is commonly used to treat pituitary adenomas, Rathke Cleft Cysts, meningiomas, craniopharyngiomas and several other tumor types.
Endoscopic–assisted “keyhole” operations
This subset of endoscopic procedures takes advantage of small “keyhole” size bony windows and smaller incisions to access the target area. The tumors most commonly treated via keyhole operations are meningiomas, craniopharyngiomas and pituitary adenomas, in addition to several others. These surgeries can often be performed using a small incision in the eyebrow or behind the hairline, which typically cannot be seen once healed. Depending on the location in the brain, a keyhole approach can be performed for several types of tumors and cysts. It is generally believed that the smaller bony openings and incisions used in these approaches result in decreased incidence of infections and complications such as cerebrospinal fluid (CSF) leakage.
Neuro-endoscopic intraventricular operations
The cerebral ventricles are a connected series of chambers deep in the brain that produce and circulate CSF throughout the nervous system. At times, the normal pathways of CSF circulation can become blocked by tumors, cysts, or other conditions, resulting in a buildup of fluid and raised intraventricular pressure known as hydrocephalus. Because the ventricles are anatomically deeper structures, they can be a challenge to operate within using more traditional approaches. Neuro-endoscopic approaches to intraventricular conditions have become the preferred way to treat many conditions arising within the ventricular system, including colloid cysts, arachnoid cysts, some intraventricular tumors and some forms of hydrocephalus. Typically, a small incision is made behind the hairline in the frontal area, and a dime–sized hole is created for insertion of the endoscope into the ventricle. Sometimes, a procedure called an endoscopic third ventriculostomy (ETV) can be performed to treat hydrocephalus and may eliminate the need for implanting a permanent CSF shunt.
The NICO BrainPath® is an innovative tool used to surgically operate on deep-seated tumors in the brain without causing injury to healthy brain tissue. The tool is also used to access deep vascular lesions, including intracerebral hemorrhages. This minimally invasive surgery uses brain imaging, neuro-navigation, access, optics, tissue resection and regenerative medicine, which allows neurosurgeons to safely remove tumors that may have been previously deemed inoperable due to location or size.
The procedure requires an opening less than the size of a dime and uses brain mapping, GPS navigation and the BrainPath® tool to safely move through the natural folds and delicate fibers of the brain. The tool allows neurosurgeons to reposition healthy brain tissue when locating a tumor or lesion, instead of cutting it, lowering the risk of complications and shortening length of hospital stay. The BrainPath® also creates a clear passageway for surgeons to maintain access to the tumor or lesion for removal.