Our residents come from a variety of different background. Learn more about them below.

We provide our residents with a competitive salary and other program-specific benefits.

PGY-7 | Class of 2021

Nathan Pratt

Nathan Pratt, MD
University of Oklahoma College of Medicine

Dr. Pratt completed additional training in complex and deformity spinal surgery with Dr. Sansur. He will begin a fellowship at Swedish Neuroscience Institute in complex spinal surgery beginning in 2021.

Aaron Wessell

Aaron Wessell, MD
MD: George Washington University School of Medicine and Health Sciences 

Dr. Wessell’s clinical interests include comprehensive care for patients with cerebrovascular disease, skull base surgery, and management of traumatic injuries of the head and spine.

During his residency, Dr. Wessell completed a one-year enfolded fellowship in Endovascular Neurosurgery with the Division of Neurointerventional Radiology.

He is actively involved in clinical research and is currently participating in several ongoing studies pertaining to the prevention of secondary brain injury following subarachnoid hemorrhage and mechanical thrombectomy for treatment of acute ischemic stroke.

Dr. Wessell’s awards include the RUNN Resident Award from the Society of Neurological Surgeons and the William T. Gill Research Fellowship from the George Washington University School of Medicine.

Dr. Wessell is a native of Stevens Point, WI. In his free time, he enjoys running, weight-lifting and spending time with his wife and kids.

Career interests: Dr. Wessell plans to pursue a career in academic cerebrovascular/endovascular neurosurgery. Following residency, he will be completing a cerebrovascular/CAST-accredited neuroendovascular fellowship at the Mayo Clinic in Jacksonville, Florida.

PGY-6 | Class of 2022

Greg Cannarsa

Gregory Cannarsa, MD
Jefferson Medical College of Thomas Jefferson University

Greg Cannarsa is recently finished a dedicated endovascular neurosurgery fellowship with Neuro-Interventional Radiology. He plans to pursue a career as a dual-trained vascular neurosurgeon. His hobbies are running and watching Philadelphia Eagles football.

Tim Chryssikos

Timothy Chryssikos, MD, PhD
University of Maryland School of Medicine

Dr. Chryssikos grew up in Maryland and graduated from Swarthmore College. He joined the neurosurgery residency program after graduating from the University of Maryland School of Medicine, where he was elected to the AOA Honor Medical Society and received the Raymond K. Thompson Award from the Department of Neurosurgery. He completed a PhD in anthropology at Rice University on the social relations of scientific research, for which he received the John W. Gardner Award for best dissertation in the School of Social Sciences. He will pursue a fellowship in spine surgery at the University of California, San Francisco upon completion of the residency program.

PGY-5 | Class of 2023

Nick Caffes

Nicholas Caffes, MD
University of Maryland School of Medicine

Dr. Caffes is interested in open and endovascular cerebrovascular surgery as well as traumatic brain and spinal cord injury. Dr. Caffes plans to complete an enfolded interventional neuroradiology fellowship. His hobbies outside of work include hiking, cooking, and traveling. 

Jeff Oliver

Jeffrey Oliver, MD
Jefferson Medical College of Thomas Jefferson University

Dr. Oliver is interested in a career in trauma and vascular neurosurgery.  His interests outside of work include Penn State football, exercising, and spending time with his family.  

PGY-4 | Class of 2024

Nathan Han

Nathan Han, MD
New York University School of Medicine

Nathan Han is a graduate from Rice University, attended New York University medical school and is now a third year resident in Neurosurgery at University of Maryland Medical Center. Outside of work, he enjoys listening and playing classical music with his pianist wife. 

Ashiah Sharma

Ashish Sharma, MD
Medical College of Wisconsin

Dr. Sharma has an interest in open and endovascular Neurosurgery as well as complex deformity spine surgery. He plans to pursue an infolded endovascular fellowship. His hobbies include exercise, trying new foods, and spending time with family, friends and his dog.

PGY-3 | Class of 2025

Abdul Ahmed

Abdul-Kareem Ahmed, SM, MD
Undergraduate: University of Pittsburgh
Graduate School: Massachusetts Institute of Technology
Medical School: Warren Alpert Medical School of Brown University

Dr. Ahmed has several interests in neurosurgery, including brain tumors, movement disorders, and epilepsy. He is involved in outcomes research and studying the use of MRI-guided focused ultrasound surgery to treat patients with these diseases. Dr. Ahmed was awarded an NREF grant and an ABTA grant in medical school, to study multimodality monitoring in neuro-ICU patients and to study immunotherapy for glioblastoma, respectively. He studied science writing in graduate school and occasionally writes reflectively on experiences he’s had in medicine. Dr. Ahmed is from Wakefield, RI, and enjoys ocean swimming, walking on the beach, and canoeing, whenever possible.

Career interests: image-guided neurosurgery, neuro-oncology, functional neurosurgery 

Joshua Olexa

Joshua Olexa, MD
University of Maryland School of Medicine

Dr. Joshua Olexa's clinical interests include degenerative spinal pathology and Neurosurgical trauma. His hobbies outside of Neurosurgery include running, snowboarding, and fishing.

PGY-2 | Class of 2026

Phelan Shea

Phelan Shea, MD, PGY-1
University of Maryland School of Medicine

Dr. Shea is a Boston native who attended the University of Maryland for medical school. He is interested in cerebrovascular neurosurgery and his research has been featured in journals and national meetings. He is a Pisces and enjoys playing hockey. 

Jesse Stokum

Jesse Stokum, MD, PhD
University of Maryland School of Medicine

Dr. Stokum has interests in cerebrovascular neurosurgery and neurocritical care. His research is primarily focused on the astroglial response to brain injury and the molecular mechanisms that drive cerebral edema formation. Outside of work, he likes to spend time with his daughter.

PGY-1 | Class of 2027


Riccardo Serra, MD

MD: Catholic University of the Sacred Heart (Rome, Italy)


Nicole Wenger, MD, MBA

MD: Ohio State University College of Medicine

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