A well-informed partnership
for your healthcare

East Bay Brain & Spine Medical Group believes in educating patients in order to help them make well-informed decisions. We aim to maximize function, avoid surgery when possible, and to minimize recovery time so that patients return to their activities as quickly as possible. Using clear explanations and conversation, we take great pride in guiding patients through stressful times in their lives.

Maxwell B. Merkow, MD, FAANS

Dr. Merkow is a board-certified neurosurgeon with East Bay Brain & Spine Medical Group and BASS Medical Group in Walnut Creek, California. He specializes in minimally invasive approaches for both common and complex spinal disorders as well as brain and pituitary tumors, including stereotactic radiosurgery. Dr. Merkow treats Parkinson’s disease and essential tremor with deep brain stimulation, and he alleviates facial pain via microvascular decompression and focused radiation. His practice includes the management of cerebral aneurysms. Dr. Merkow is an expert in surgical navigation, which he finds enhances surgical precision and improves patient outcomes.

After receiving his medical degree from Columbia University’s College of Physicians and Surgeons, Dr. Merkow completed a seven-year residency in neurological surgery at the University of Pennsylvania and a clinical fellowship at Wellington Public Hospital in New Zealand.  Dr. Merkow has published research on memory, brain rhythms, and brain stimulation in such journals as Science and Proceedings of the National Academy of Sciences.

Dr. Merkow has extensive experience caring for the gamut of spine and brain issues. He takes pride in providing excellent, individualized neurosurgical care in the community setting.

Dr. Merkow practices in Walnut Creek, California and has full privileges at John Muir Medical Center and the BASS ambulatory surgery center. He serves as the Neurosurgical Division Chair, Neurosurgical Medical Director, and Spine Program Consultant at John Muir Medical Center 

Matthew A. Piazza, MD


Dr. Matthew Piazza is a neurosurgeon with East Bay Brain & Spine Medical Group and BASS Medical Group in Walnut Creek, California. He specializes in the surgical treatment of neurologic conditions affecting the spine, brain, and peripheral nerves. He treats a breadth of spine conditions including cervical, thoracic, and lumbar spine degenerative disease, adult degenerative spinal deformity, spine trauma, and spinal tumors. Dr. Piazza’s primary goal is to provide patients with the maximum benefit with the smallest intervention using the latest surgical techniques and evidenced-based management. He believes that the patient–surgeon relationship is a partnership, and he strives to work with his patients to achieve the best outcome from both surgical and non-surgical treatments.

After graduating from Princeton University, Dr. Piazza received his medical degree at Columbia University College of Physicians and Surgeons. He completed his neurosurgical training at the University of Pennsylvania. While at the University of Pennsylvania, he served as an internal fellow in spine surgery during which time he received specialized training in the surgical management of complex spinal disorders including degenerative spinal disease, adult degenerative spinal deformity, spinal oncology, and spine trauma. His post-doctoral research focused on quality improvement in peri-operative neurosurgical care and the development of animal models for studying spinal disc regenerative therapies.

Dr. Piazza practices in Walnut Creek and has privileges at John Muir Medical Center’s Walnut Creek Campus.

Ehsan Ejaz, PA-C - Board-certified Physician Assistant

Ehsan Ejaz, PA-C

Ehsan Ejaz is a board-certified physician assistant with a passion for neurophysiology and neurosurgery. Ehsan received his B.S. in Neurobiology, Physiology, and Behavior at UC Davis where he conducted extensive research at the Medical Investigation of Neurodevelopmental Disorders (M.I.N.D.) Institute at UC Davis and the Institute for Pediatric Regenerative Medicine at Shriners Hospital. Ehsan began gaining experience as a surgical neurophysiologist at Yale New-Haven Hospital.  He has conducted over 2000 intraoperative neuromonitoring consultations on a wide variety of cases. Keen to further his passion for neurosurgery and patient care, Ehsan then completed his Masters in Physician Assistant Studies at Samuel Merritt University. Ehsan’s philosophy for patient care involves empowering patients as equal members of their health care team, as patients are their own best advocates. Ehsan practices evidence-based medicine. He stays abreast of the latest developments and research by reviewing medical and neurosurgical literature as well as attending conferences. When he is not at the bedside or in the operating room, Ehsan can be found traveling to new places, hiking California’s expansive state parks, or capturing the perfect Milky Way photograph.

Kyleigh Coker, Medical Assistant

Kyleigh Coker

Medical Assistant

Kyleigh’s passion for helping others fueled her career choice. This trait also explains her steadfast compassion, which combined with excellent communication skills helps our patients navigate their complex problems. East Bay Brain & Spine/BASS Neurosurgery is fortunate to have Kyleigh as part of our team. In Kyleigh’s spare time she loves to travel, craft and spend time with her family.
Yadira Martinez, Medical Assistant

Yadira Martinez

Medical Assistant
Yadira brings a passion for helping those in need to East Bay Brain & Spine/BASS Neurosurgery Division. The practice and our patients benefit from her diligence, sensitivity, and caring attitude. She is an integral member of our team. In her free time, Yadira likes to enjoy time with her friends and family, explore new hiking trails, and try new recipes.