Group picture of residents in front of Davidge Hall

Our residents come from a variety of different backgrounds. 

We provide our residents with a competitive salary and other program-specific benefits. We also offer wellness and support resources to help residents maintain a healthy balance.

Learn more about our current residents below.

Greg Cannarsa

PGY-7 | Class of 2022

Gregory Cannarsa, MD
Undergraduate: Saint Joseph's University
Medical School: Jefferson Medical College

Dr. Cannarsa is most interested in vascular neurosurgery, both open and endovascular, as well as trauma neurosurgery. His research interests include middle meningeal artery embolization for chronic subdural hematoma, transverse sinus stenting for intracranial venous hypertension, the toxicity of blood in the CNS, and techniques for surgical evacuation of intracerebral, subarachnoid, and intraventricular hemorrhage. Dr. Cannarsa is from West Chester, Pennsylvania. His hobbies are running and watching Philadelphia Eagles football.

Career interests: Dr. Cannarsa plans to pursue a career as a dual-trained vascular neurosurgeon and has accepted a position at the Swedish Neuroscience Institute for a combined open vascular/endovascular neurosurgery fellowship.

Tim Chryssikos

Timothy Chryssikos, MD, PhD
Undergraduate: Swarthmore College
Graduate School: Rice University
Medical School: University of Maryland School of Medicine

Dr. Chryssikos grew up in Maryland and joined the 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. His clinical and research interests in neurosurgery include trauma and spine.

Career interests: Dr. Chryssikos will pursue a fellowship in spine surgery at the University of California, San Francisco upon completion of the residency program.

PGY-6 | Class of 2023

Nick Caffes

Nicholas Caffes, MD
Undergraduate: University of Maryland, College Park
Medical School: University of Maryland School of Medicine

Dr. Caffes has interest in open and endovascular cerebrovascular surgery. He is currently completing a one-year enfolded fellowship in Endovascular Neurosurgery with the Division of Neurointerventional Radiology. His research interests are in the endovascular management of ischemic stroke and outcomes following traumatic spinal cord injury. Dr. Caffes has received research scholarships through the AOA and AANS for his work in neuroinflammation following intracerebral hemorrhage. Dr. Caffes grew up in the Maryland suburbs outside Washington D.C. His free time is spent with his wife and Labrador retriever. He enjoys hiking in the Shenandoah Valley, cooking, reading, and weight-lifting.

Career interests: Dr. Caffes accepted a Cerebrovascular Fellowship position starting in July 2023 at the Swedish Neuroscience Institute.

Jeff Oliver

Jeffrey Oliver, MD
Undergraduate: The Pennsylvania State University
Medical School: Jefferson Medical College

Dr. Oliver’s clinical and research interests include the care of neurotrauma and cerebrovascular patients. He is currently completing a one-year enfolded fellowship in Endovascular Neurosurgery with the Division of Neurointerventional Radiology. He grew up in Middletown, Delaware and attended Penn State and Jefferson as a part of their 6-year combined BS/MD program. He was a member of AOA Honor Medical Society and graduated Magna Cum Laude from Jefferson Medical College. His hobbies and interests outside of work include exercising, spending time with his friends and family, and Penn State football.

Career interests: Dr. Oliver accepted a Cerebrovascular Fellowship position at Geisinger Medical Center starting in July 2023.

PGY-5 | Class of 2024

Nathan Han

Nathan Han, MD
Undergraduate: Rice University
Medical School: New York University School of Medicine

Dr. Han is a originally from Cupertino, CA. He is a member of Phi Beta Kappa and recipient of AOA Carolyn Kuckein Research Fellowship. His research interest includes spinal cord neuro-protection in the setting of radiation, and factors associated with lumbosacral fusion stability. For his prior work in hydrocephalus, Dr. Han won the Top Poster Award in Pediatrics at the 2015 AANS Meeting. In his spare time, he plays the piano and creates recordings with his pianist wife.

Career interests: Dr. Han accepted a position as a Spine Surgery Fellow at the University of California San Francisco, which will start in July 2024.

Ashiah Sharma

Ashish Sharma, MD
Undergraduate: University of Alabama/Marquette University
Medical School: Medical College of Wisconsin

Dr. Sharma grew up in Edmonton, Alberta before moving with his family to Huntsville, AL. He attended the University of Alabama before completing his degree in Biochemistry from Marquette University and attending medical school at the Medical College of Wisconsin. His clinical interests include complex spine surgery. When not at work, he enjoys cooking, spending time with his friends and Pomeranian, Boo-Boo, and is also in charge of organizing the residents’ social gatherings.

Career interests: Dr. Sharma is interested in complex spine surgery.

PGY-4 | Class of 2025

Abdul Ahmed

Abdul-Kareem Ahmed, MD, SM
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 movement disorders and spine surgery. He is involved in studying the use of MRI-guided focused ultrasound to treat patients with movement disorders and brain tumors. 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.

Career interests: Dr. Ahmed is interested in functional neurosurgery and spine surgery.

Joshua Olexa

Joshua Olexa, MD
Undergraduate: St. Mary’s College of Maryland
Medical School: University of Maryland School of Medicine

Dr. Olexa’s clinical and research interests include degenerative spinal pathology and neurosurgical trauma. His research has focused on decompression for traumatic spinal cord injury. Dr. Olexa’s hobbies outside of neurosurgery include running, snowboarding, and fishing.

Career interests: Dr. Olexa is interested in complex spine surgery and trauma neurosurgery.

PGY-3 | Class of 2026

Phelan Shea

Phelan Shea, MD
Undergraduate: Goucher College
Medical School: University of Maryland School of Medicine

Dr. Shea attended the University of Maryland for medical school, where he graduated magna cum laude and received awards for his publications and scientific contributions. Dr. Shea is interested in both open cerebrovascular and endovascular neurosurgery as well as minimally invasive spine. He is a Boston native who enjoys playing hockey.

Career interests: Dr. Shea plans on pursuing an open and endovascular fellowship starting in his PGY-7 year. He enjoys the diversity of the Baltimore population and would ultimately like to work long term in this area.

Jesse Stokum

Jesse Stokum, MD, PhD
Undergraduate: West Virginia University
Graduate School: Carnegie Mellon University, University of Maryland Baltimore
Medical School: University of Maryland School of Medicine

Dr. Stokum is passionate about basic science and clinical research, and has a particular interest in the molecular mechanisms and treatment of secondary injury after ischemic stroke, hemorrhagic stroke, and traumatic brain injury. He completed a PhD in neuroscience studying the molecular mechanisms of cerebral edema formation under the guidance of Dr. J. Marc Simard. He is a member of AOA and the recipient of the William H. Mosberg Jr. Award for Neurosurgery. Jesse was raised in rural southwestern PA, and enjoys home projects, running, and having fun with his wife and their curly-haired daughter.

Career interests: Dr. Stokum is pursuing an academic career in cerebrovascular and endovascular neurosurgery.

PGY-2 | Class of 2027


Riccardo Serra, MD
Undergraduate: Liceo Classico Dante Alighieri, Latina, Italy
Medical School: Catholic University of the Sacred Heart Medical School, Rome, Italy
Post-Doctoral Fellowships: Johns Hopkins University

Dr. Serra has many interests in neurosurgery, including neuro-oncology and vascular neurosurgery, CSF disorders and hydrocephalus. His research background includes drug delivery and drug re-purposing for glioblastoma and medulloblastoma, CSF shunting systems, and novel pathways (glymphatics, lymphatics) of CSF and interstitial fluid flow in the brain. For his work, Dr. Serra was the recipient of the Hydrocephalus Association Young Investigator Award, and the Earl Walker Outstanding International Postdoctoral Fellow Award from Johns Hopkins University School of Medicine. Dr. Serra hails from Rome, Italy. In his free time, he enjoys sailing, reading modern and classic literature, gardening, contemporary art, and biking with his wife.

Career interests: Neuro-Oncology and skull base surgery, with a special interest in open vascular neurosurgery and hydrocephalus.


Nicole Wenger, MD, MBA
Undergraduate: Yale University
Graduate School: Ohio State University Fisher College of Business
Medical School: Ohio State University College of Medicine

Dr. Wenger is interested in cerebrovascular neurosurgery. Having completed an MBA in medical school, she is also interested in quality and process improvement as well as how we systematically deliver healthcare. She grew up on a pig farm in Illinois and enjoys rugby, hiking, and spending time with her two cats and two dogs.

Career interests: Dr. Wenger is currently most interested in pursuing open vascular and endovascular neurosurgery, although maintains an interest in other subspecialties.


PGY-1 | Class of 2028

Shreyas Panchagnula headshot

Shreyas Panchagnula, MD, MHS
Undergraduate: Yale College
Medical School: Yale School of Medicine

Dr. Panchagnula grew up in New Jersey before attending Yale College, completing a Bachelor of Science in Biomedical Engineering with a focus in biomolecular engineering and drug delivery research. He attended Yale School of Medicine to complete a joint degree, Doctor of Medicine (cum laude) and Master of Health Science, pursuing genomics research in congenital hydrocephalus and other neurosurgical disorders. His use of integrative genomics to investigate neurodevelopmental origins of congenital hydrocephalus was published in a Nature Medicine. He was also awarded the Best Basic Science Award in the Pediatrics section of CNS 2020 and the Nicholas J. Giarman Prize for an outstanding medical student thesis. In his free time, Dr. Panchagnula enjoys traveling, playing the piano, and delving into music composition.

Career interests: Dr. Panchagnula is exploring his numerous interests across the field of neurosurgery. 

Parantap Patel headshot

Parantap Patel, MD
Undergraduate: Virginia Commonwealth University
Medical School: University of Virginia

Dr. Patel was born in New York City and raised in southeast Virginia. He graduated summa cum laude from Virginia Commonwealth University where he developed a strong research interest in neurotrauma, with particular focus in biomarkers and predictive modeling. He completed medical school at the University of Virginia where he developed a clinical interest in spinal surgery. In his spare time, Dr. Patel enjoys practicing archery, playing tennis, and spending time with his wife and family.

Career interests: Dr. Patel is most interested in complex spine surgery and neurotrauma.

Incoming Interns

Kevin Kim headshot

Kevin Kim, MD
Undergraduate: University of California
Medical School: University of Maryland, School of Medicine

Dr. Kim was raised in Clarksville, MD and graduated from UCLA with a BS in neuroscience, after which, he completed a research year in neuroscience at Johns Hopkins before attending the University of Maryland, School of Medicine. Outside of the hospital, Kevin plays competitive soccer and enjoys hiking, golfing, and anything outdoors related. 

Career Interests: Dr. Kim is interested in cerebrovascular and skull base neurosurgery but is generally open to all fields of neurosurgery.

Steven Yarmoska headshots

Steven Yarmoska, MD, PhD
Undergraduate: Duke University
Medical School: Emory University, School of Medicine

Dr. Yarmoska has spent the last seven years in Atlanta, GA at Georgia Tech and Emory University. He has enjoyed his time helping to manage neurotrauma at Grady and Harborview, and hopes to bring the same enthusiasm to Shock Trauma. Dr. Yarmoska enjoys cooking, baking, and trying new restaurant and breweries. He is an avid soccer and college sports fan as well

Career Interests: Dr. Yarmoska’s current clinical interest in neurosurgery are in functional and neuro-oncology. Research-wise, he would like to leverage his graduate studies at Tech to work on expanding the utility of intraoperative ultrasound.


Find Us On Social