Epilepsy Surgery

Patients with epilepsy whose seizures do not effectively respond to two antiseizure medications are considered to have drug-resistant epilepsy (DRE). DRE accounts for approximately 30% of the adult population living with epilepsy. Your epileptologist may refer you for a surgical workup if you have DRE. The objective of surgery is to decrease seizures, the severity of seizures, or to become seizure-free. We offer many types of epilepsy surgery at Denver Health. Epilepsy surgery evaluation often involves figuring out what type of epilepsy you have, where the seizures are starting from in your brain, and if this is an area of the brain where surgery can be done. The possible epilepsy surgery treatment options are decided based on the answers to these questions.

Surgical Options at Denver Health


  1. Vagus Nerve Stimulator: VNS Therapy is a neuromodulation treatment designed for people with drug-resistant epilepsy. This same-day surgery is minimally invasive and was one of the first FDA-approved surgical device therapies for epilepsy. VNS Therapy is a small device implanted under the skin below the left collarbone and connected to the left vagus nerve in the neck. Mild electric pulses are delivered to the brain through the vagus nerve to help decrease the number of seizures and the severity of seizures.
  2. Responsive Neurostimulation (RNS) Therapy: This surgical approach to treating seizures that are not controlled by medication utilizes a neurostimulator that is placed within the skull. This RNS neurostimulator is connected to 2 electrodes placed either on the surface of the brain, into the brain, or a combination of both. The electrical activity of the brain is constantly monitored by the RNS and it stimulates the brain with electric pulses when it detects a seizure and at other times to disrupt the seizure pathways. Also, select data is saved and uploaded so that your epileptologist can review it and alter the device for optimal seizure detection and treatment.
  3. Deep brain stimulation (DBS): DBS is the use of a device that is placed deep inside the brain. The device releases regularly timed electrical signals that disrupt the seizure pathways and help to decrease the number of seizures and the severity of seizures. This procedure is guided by an MRI when it is placed. The generator that sends the electrical pulse is implanted in the upper chest below the collarbone.

Intracranial monitoring, also called Phase 2 monitoring, refers to seizure monitoring done with electrodes placed inside the skull, on the surface of or within the brain. This is done only when the seizure onset is not clear after regular monitoring with the scalp EEG (called Phase 1) and other studies including brain MRI, PET scans, etc. Intracranial electrodes are placed by a neurosurgeon in the operating room with the patient asleep under general anesthesia. Stereoelectroencephalography (SEEG) uses brain scans and robotic machines to plan and guide the placing of depth electrodes into the brain. Sometimes small flat sheets of electrodes are placed on the surface of the brain. The electrodes are put over or in the areas of the brain where the seizures are expected to start. Then patients are monitored again in the EMU to determine the seizure origin. This typically takes several days and afterwards, the electrodes are removed.

RF Ablation: Radiofrequency ablation (RFA) uses radio waves to create a current that heats a small area of brain tissue. The heat destroys that area of the brain. RFA may be able to be done in the brain area where the seizures start and by destroying this area of the brain it can stop the seizures. RFA can be done at the bedside using the Phase 2 intracranial electrodes and does not require for it to be done in the OR.

Resective surgery: Resection involves the removal of a small portion of the brain. The neurosurgeon removes brain tissue from the area of the brain where seizures start. This is usually the site of a tumor, brain injury, blood vessel abnormalities, or abnormal brain development.

Who is part of your surgical workup?

Neurosurgeon: A neurosurgeon is a physician who specializes in the diagnosis and surgical treatment of disorders of the nervous system. Surgeries performed at Denver Health’s Level Four Epilepsy Center will be performed by a surgeon with expertise in epilepsy.

Neuroradiology: Neuroradiologists play an integral role in the surgical process by interpreting several different types of brain scans and providing expertise to epileptologists. Some of these scans include magnetic resonance images (MRI), positron emission tomography (PET), and computed tomography (CT) scans of the brain.

Neuropsychology: A neuropsychologist is a physician who has expert knowledge of how various brain conditions affect your behavior and cognitive skills.

Speech Pathologist: Speech Pathologists provide vital support to individuals with epilepsy by assessing their speech and language abilities, identifying areas of difficulty, and diagnosing related disorders. They develop personalized treatment plans to improve communication skills and manage speech and language challenges. Speech Pathologists are sometimes present during surgery as needed and assist with Wada tests.

Surgical Workup Process

Patient Care Conference (PCC): Once all diagnostics that your doctor ordered have been completed for your epilepsy surgery workup, your epileptologist will present all the data at our PCC. PCC is attended by our epileptologists, neuroradiologists, neuropsychologists, neurosurgeons, speech therapists, EEG technologists, and neurology residents. After presenting all your data and test results a decision will be made by the group about the best next steps and plans. The Epilepsy Coordinator will call you to schedule an appointment to go over the next steps with your epileptologist and then a referral to neurosurgery is placed if the group decision is for you to proceed with surgery and you choose to move forward.

WADA: The Wada test determines which side of the brain controls a patient’s language and memory abilities. With this information, the neurosurgeon will aim to protect those areas and prevent complications with your speech, and memory.

Neuropsychology Testing: Neuropsychologists perform comprehensive assessments that aim to identify the patient’s cognitive strengths and weaknesses, as well as to evaluate the status of overall brain function, different brain regions, and networks. The tests include thinking, problem-solving, reading, visual identification, naming, other language functions, and memory. Testing helps identify areas where the patients may have problems, which are usually the areas where seizures are starting or happening.

Positron emission tomography (PET): A Brain PET can potentially identify regions in the brain that are related to the onset of seizures. This test shows the brain’s usage of oxygen and sugar and is typically ordered as part of the surgical workup.

Magnetic resonance imaging (MRI): An MRI scan can potentially identify structural changes in the brain that may cause seizures. This is a standard test for anyone who has had a seizure or seizures and is part of a surgical work-up.

Magnetoencephalography (MEG): A MEG scan is a test that uses sensors to look at the magnetic fields in the brain, whereas EEG looks at the electrical activity of the brain. An abnormal MEG result is then used to help locate the abnormal area in the brain where the seizures may be starting.

Other Potential Tests
fMRI and SPECT: These tests will be discussed further by your doctor to see if they are needed.

*For questions about scheduling any of these tests, please reach out to the Epilepsy Coordinator at 303-602-4368.