John Demko, MD

Recognized in Philadelphia magazine's annual Top Docs issues 2020-2023

Dr. Qingyang (Kristy) Yuan is an Associate Professor of Clinical Neurology at the Penn Neuroscience Center, specializing in the care of patients aged 18 and up. With a distinguished educational background from Johns Hopkins University School of Medicine and further training at renowned institutions, she is known for her engaging and approachable demeanor, making her patients feel comfortable during consultations. Dr. Yuan has received high ratings from her patients, reflecting her commitment to addressing concerns and providing informative care. She accepts a wide range of insurance plans, ensuring accessibility to her services for diverse patient populations. Generated from the website

Dr. Vollmer is the Chief of the Division of Gastrointestinal Surgery, and the Director of Pancreatic Surgery at Penn Medicine. He also serves as the founding Co-Director of the Penn Pancreatic Cyst Multidisciplinary Program. His practice at Penn Medicine encompasses both malignant and benign conditions of the pancreas and biliary system with a strong emphasis in care of pancreatic cancer, cysts, and pancreatitis. He specializes in Pancreaticobiliary and other complex gastrointestinal surgery with a research focus in clinical outcomes assessment in high-acuity surgery – especially pancreatic fistula. He has authored over 200 manuscripts, 40 book chapters, and 3 books focusing on pancreaticobiliary diseases. He is active in multiple national and international surgical societies where he has served in numerous leadership positions including President of the Americas Hepato-Pancreato-Biliary Association (AHPBA) in 2019. He also currently sits on the Executive Committee of the IHPBA as its Treasurer-elect and was its Scientific Program Chair for the 2016 World Congress in Sao Paulo, Brazil. He is a reviewer for numerous surgical specialty journals and is on the Editorial Boards of Annals of Surgery, British Journal of Surgery, Annals of Surgical Oncology, Surgery, HPB, the Journal of Gastrointestinal Surgery, Langenbeck’s Archives of Surgery, and the Journal of Surgical Oncology. He is a member of the American Surgical Society, Society of Clinical Surgeons, and the Surgical Biology Club II. In 2008, he was honored to be the Josef Fischer Traveling Fellow in Academic Surgery for the Society of Surgery of the Alimentary Tract (SSAT) – an opportunity which allowed him to tour many of the top pancreatic surgical programs in Europe. Education: Dr. Vollmer’s collegiate education was at the University of North Carolina at Chapel Hill. He then received his MD degree from Jefferson Medical College in his hometown of Philadelphia. From there he received general surgical training at the Barnes-Jewish Hospital of the Washington University of St. Louis where he was elected into Alpha Omega Alpha. He studied gene therapy as a surgical oncology research fellow at the University of California, Los Angeles (UCLA) in the middle of his clinical training. After Chief Residency at Washington University, he matriculated to the internationally acclaimed Hepatobiliary and Solid Organ Transplantation Surgery Fellowship at the University of Toronto. He initiated his career as an attending surgeon at the Beth Israel Deaconess Medical Center at Harvard Medical School (2003 -2011). Recognized by Best Doctors in America 2015 - 2018