MARK CALAYAG, M.D.

<p>Dr. Mark D. Calayag, M.D. is a neurological surgeon practicing at UCI Orange Neurosurgery, located at 200 South Manchester Avenue, Suite 210, in Orange, California (ZIP 92868). His NPI, 1336373901, is listed under the Neurological Surgery taxonomy in the NPPES NPI Registry maintained by the Centers for Medicare &amp; Medicaid Services, with an enumeration date of May 2009 and an active status as of the registry&apos;s January 2025 update. The practice can be reached at (714) 456-6966, Monday through Friday.</p><p>Dr. Calayag earned his Doctor of Medicine degree from Albany Medical College in 2009 and completed his neurological surgery residency training at that same institution. He subsequently pursued two subspecialty fellowship programs: a Pediatric Neurosurgery fellowship at Rady Children&apos;s Hospital–San Diego, and a Skull Base Surgery fellowship at UCI Medical Center in Orange, California, completed during the 2016–2017 academic year. He holds board certification through the American Board of Neurological Surgery, as documented in the Kaiser Permanente Southern California physician directory.</p><p>His clinical practice spans several subspecialties within neurological surgery, including cerebrovascular neurosurgery, pediatric neurosurgery, pituitary surgery, and skull base surgery. These areas address conditions such as traumatic brain injury, intracranial hemorrhage, pediatric neurological disorders, and complex cranial and spinal pathology — presentations that arise with regularity in personal-injury matters stemming from vehicular collisions and other high-impact traumatic events. Dr. Calayag has also contributed to the peer-reviewed literature on pediatric neurosurgical topics, per his Doximity professional profile.</p><p>Dr. Calayag holds California Physician and Surgeon License No. A137268 and is affiliated with the Southern California Permanente Medical Group, which he joined in 2017, as noted in the Kaiser Permanente Southern California physician directory. Hospital affiliations reflected on his Healthgrades profile include Kaiser Permanente Fontana Medical Center, Kaiser Permanente Orange County–Anaheim Medical Center, and Kaiser Permanente Moreno Valley Medical Center. He is enrolled in the Medicare PECOS system and is authorized to order and refer services for Medicare-eligible patients. The office at (714) 456-6966 handles inquiries regarding scheduling, plan acceptance, and case-type availability. Prior outcomes associated with any provider or case type do not guarantee comparable results in future matters.</p>