Our ProgramThe Surgical Neurophysiology Program at Keck Medicine of USC in Los Angeles is unlike any surgical monitoring program in the country; it provides all aspects of surgical neurophysiology to greatly reduce the risk of damaging key nervous system areas during surgery.
The program consists of three parts: intraoperative monitoring, brain mapping and brain implants.
- Intra-operative monitoring reduces risk and improves outcomes during brain, spine head and neck surgery or other surgeries where any part of the nervous system is at risk. By monitoring the electrical signals of nerve cells in the brain and spinal cord during surgery, the program at Keck Medicine of USC in Los Angeles can help prevent injuries like stroke or paralysis during any of these operation.
- Brain mapping localizes important functions of the brain, such as language, motor function, vision and sensation- brain areas that can vary a great deal between individuals. As a consequence, surgeons will know which key areas to bypass when performing operations, sparing vital structures in the brain.
- Brain implants: We use deep brain stimulation for the treatment of conditions like Parkinson disease, essential tremor, dystonia and obsessive-compulsive disorder, among others. By navigating electrodes deep into the brain, we are able to locate the group of neurons that are responsible for some of the patient’s symptoms. These devices are then activated in the operating room to determine the potential for adverse effects and to confirm the correct location for surgical implant leading to improvement in symptoms.
Program physicians use a number of methods to measure nerve cell activity in the brain and spinal cord, and nerves during surgery, including evoked potentials, electroencephalograms, electrocorticography and microelectrode recording.
Program physicians work with a wide variety of surgeons, including neurosurgeons, orthopaedic surgeons , otolaryngologists (ear, nose and throat specialists), movement disorder specialists, interventional neuroradiologists and vascular surgeons. The program monitors and assists surgeons at Los Angeles County+USC Medical Center as well as the hospitals at the Keck Medical Center of USC.
As part of a large university-based medical center, program physicians are involved in research projects aimed at improving monitoring, deep brain stimulation and mapping capabilities, as well as testing new surgical techniques to treat a variety of conditions including aneurysms, brain and spinal cord tumors, complex spine conditions, head and neck tumors among others. Physicians at the program also have authored several chapters in the most widely used textbooks on neurophysiological monitoring.
Number of patients monitored per year
Keck Medical Center of USC: 1,200
LAC+USC Medical Center: 600
Treatments and ServicesWhile many patients admitted to Keck Medical Center of USC might never meet the intraoperative neurophysiological monitoring team, the program provides a vital, almost behind-the-scenes service to help ensure that operations on the nervous system proceed smoothly.
The team can first map the patient’s brain and spinal cord to specific key areas of the brain, including centers for speech, motor/muscle control, hearing, vision and sensation. During the operation, physicians watch electronic monitors for abnormal nerve cell electrical activity, and work with the Movement Disorders Center specialists to determine the exact, correct placement of deep brain stimulation electrodes used to treat movement and other disorders.
Among the techniques used by the Intraoperative Neurophysiological Monitoring team are:
Evoked potentials ¬– measure electrical activity of specific nerve cells and neural pathways. These include somatosensory evoked potentials (SSEP), brainstem auditory evoked potentials (BAEP), motor evoked potentials (MEP) and visual evoked potentials (VEP).
Electroencephalogram (EEG) – measured from electrode sensors placed on the scalp, this measures waves from nerve cells in the brain.
Electrocorticography – measured directly on the surface of the brain (on a sheathing layer called the pia mater). This method measures specific resection areas for epilepsy surgery and monitors for seizures during brain mapping procedures.
Mapping grids – determine areas of seizures in epilepsy and other disorders. Subdural grid electrodes record activity and stimulate neural tissue to identify the underlying function.
Mapping using monopolar probes – guided by magnetic resonance imaging (MRI), these probes are used both for navigation and stimulation purposes during the resection of brain tumors.
Deep brain stimulation (microelectrode) – recording uses high-frequency recording techniques to precisely identify locations of deep within the brain.
Deep brain stimulation (macrostimulation) – electrical currents emitted by the deep brain stimulator. Monitoring the effects of these stimulators can determine the appropriate placement of the stimulator and subsequent clinical effects.
Jon-Paul Pepper, MD