Brain Aneurysm

Stanford Brain Aneurysm Team

Gary K. Steinberg, MD, PhD

Chair, Department of Neurosurgery
Co-Director, Stanford Stroke Center

A founding director of the Stanford Stroke Center, Dr. Steinberg has practiced medicine at Stanford for more than 20 years.

He has pioneered stereotactic microsurgical techniques to repair intracranial vascular malformations and certain aneurysms that were previously considered untreatable. He has also refined revascularization techniques for patients with cerebrovascular occlusions, as well as Moyamoya disease.

Dr. Steinberg is currently investigating an innovative approach to improve stroke recovery by transplanting neural cells into damaged brain tissue.

Steven D. Chang, MD

Director, Cyberknife Radiosurgery

Dr. Steven Chang is an Assistant Professor of Neurosurgery. Chang graduated from Stanford University in 1989 with degrees in Biological Sciences and Quantitative Economics. He earned his MD from Stanford in 1993, and remained at Stanford for his internship in General Surgery and residency in Neurosurgery, serving as Chief Resident from 1998-1999 and Fellow in Cerebrovascular Surgery in 1999-2000. 

Dr. Chang joined the Neurosurgery Faculty as Assistant Professor in 2001, and is currently the Director of CyberKnife Radiosurgery. 

As a board certified neurosurgeon, Dr. Chang specializes in the treatment of vascular disorders and tumors of the brain and spinal cord, and is one of few physicians in the world today specializing in radiosurgery treatment of tumors of the spine.

Charlie Cho, MD

Dr. Cho recently joined the Intraoperative Monitoring Service at Stanford, transferring from the Massachusetts General hospital at Harvard Medical School.

His interests are in the neurophysiology and electrical functions of the brain, spinal cord and peripheral nerves.

He is currently involved in recognizing reversible ischemia and preventing strokes during surgical and interventional neuroradiology procedures.

Huy Do, MD

Dr. Do focuses his efforts on interventional neuroradiologic approaches to treat both ischemic and hemorrhagic cerebrovascular disorders.

He has developed expertise in cerebral angioplasty and intra-arterial thrombolysis,as well as the treatment of aneurysms, arteriovenous malformations and cerebral vasospasm.

Dr. Do's current research focuses on evaluation of neuroprotectants for ischemic strokes, development of novel laser microdevices for emulsification of intracranial clots, stenting of carotid and vertebral arterial stenosis, evaluation of new liquid embolic agents for arteriovenous malformations, neuroimaging of strokes, vascular malformations, and aneurysms with advanced MRI techniques, and treatment of painful compression fractures with acrylic cement. 

Richard Jaffe, MD, PhD

Chief, Neurosurgical Anesthesia

Dr. Jaffe's research interests include the development and characterization of electrophysiologic monitoring techniques for the early detection of intraoperative cerebral ischemia.

Using these techniques he is also able to study the effects of anesthetics and related drugs on the brain's sensitivity to transient ischemic events. The results of these studies can be used to improve the anesthetic management of patients undergoing a wide variety of neurosurgical procedures.

Jaime Lopez, MD

Dr. Lopez completed his residency in Neurology and fellowship in Clinical Neurophysiology and Neuromuscular Diseases at Stanford Medicine.

In 1994, Dr. Lopez established the Intraoperative Neurophysiologic Monitoring Program at Stanford. The program has expanded to more than 500 cases annually.

Dr. Lopez continues to research the use of innovative techniques for monitoring different regions of the nervous system during a variety of neurovascular surgical procedures, endovascular embolizations, and spinal cord and orthopedic surgeries.

Michael Marks, MD

Chair, Interventional Neuroradiology

As a founding director of the Stanford Stroke Center, Dr. Marks oversees the endovascular treatment program.

Using catheter-based approaches, he has pioneered techniques to effectively cure cerebral aneurysms by inserting platinum coils and using special glues to obliterate arteriovenous malformations.

Dr. Marks has also employed endovascular techniques to treat ischemic cerebrovascular disorders. He has a broad experience with cerebral angioplasty, and he is currently developing a new laser therapy for vaporizing intracranial thrombi.

Robert Dodd, MD, PhD

Dr. Dodd received his medical degree from the Stanford University School of Medicine, where he also earned a PhD in Neurosciences from the Department of Neurobiology. His neurosurgery training also took place at Stanford, where he recently completed an endovascular fellowship. His research interests have been in cerebral blood vessel reactivity and stroke. Dr. Dodd's clinical interests include endovascular and microsurgical treatment of intracranial aneurysms and arteriovenous malformations; percutaneous and surgical interventions for both extracranial and intracranial carotid artery occlusive disease; and minimally invasive neurosurgery though the use of neuroendoscopy and keyhole approaches.

Teresa Bell-Stephens, RN, CNRN

Teresa Bell-Stephens, RN, CNRN came to Stanford Medicine from the East Coast in 1988. She worked in critical care for many years before joining the Department of Neurosurgery in 1990.  She has coordinated programs in cerebrovascular surgery since then.  She is an excellent resource for information on vascular malformations, aneurysms and moyamoya disease, and is available to guide care for patients and families before, during and after their treatment at Stanford Hospital & Clinics. Teresa has been involved in clinical research trials that have studied various methods of neuroprotection, including mild hypothermia, in patients with stroke and head injury.  Teresa regularly lectures in the Bay Area, nationally and internationally.


Joli Vavao, NP CNRN

Joli joined the Neurosurgical Team in 2004.

She has worked as a nurse for over 10 years specializing in neurosurgery and stroke neurology.

She plays an active role coordinating the care of moyamoya patients in both an inpatient and outpatient setting.


Mary Marcellus, RN

Mary has been the Interventional Neuroradiology nurse coordinator since 1993. She has been at Stanford since 1980 first as a staff nurse and then as an assistant nurse manager. 

Her current position allows her the opportunity to assist patients through the process of learning about their disease and treatment options, as well as coordinating their care and follow-up.

Melissa Lewis, NP-BC

Melissa has been a registered nurse at Stanford since 2006, working with the neurosurgery and general patient populations. She graduated from UCSF in 2011 as a nurse practitioner, and now works with patients and their families in the inpatient and outpatient settings. She coordinates care for patients with vascular malformations, Moyamoya, aneurysms and tumors.


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