Dr. Mark E. Mahan

David M. Parker, MD, FACS, FASMBS, is a board-certified general surgeon specializing in bariatric surgery for both adolescents and adults. Dr. Parker performs several advanced and specialized surgical procedures, including gastric bypass, biliopancreatic diversion with duodenal switch, revisional bariatric surgery, laparoscopic gastric band (or “lap band”) and gastric sleeve. He also provides care for various conditions affecting the stomach and gastrointestinal (GI) system, including hiatal hernia, paraesophageal hernia, achalasia and acid reflux.|He has a clinical interest in minimally invasive laparoscopic and robotic surgery.|Board-certified in general surgery, Dr. Parker earned his medical degree from West Virginia University in Morgantown. He completed a general surgery residency at the Dwight D. Eisenhower Army Medical Center in Fort Gordon, GA, followed by a fellowship in bariatric and foregut surgery at Geisinger Medical Center in Danville.|While in medical school, he received the Presidential Award for Excellence in Scholarship. During his fellowship, he received the SAGES Award for best fellow presentation.|Dr. Parker serves as program director for the Geisinger bariatric and foregut surgical fellowship. He has a strong commitment to research in bariatric and foregut surgery and has authored more than 24 published articles.|He is an active member of the Society of Gastrointestinal and Endoscopic Surgeons and a fellow of the American College of Surgeons and American Society of Metabolic and Bariatric Surgeons.|Dr. Parker has served in the United States Army and continues to serve as a lieutenant colonel in the United States Army Reserve. He is also a football enthusiast, rooting for the West Virginia Mountaineers in his free time. Dr. Parker is highly rated in 12 conditions, according to our data. His clinical expertise encompasses Hiatal Hernia, Hernia, Obesity, Gastric Bypass, and Endoscopy. Dr. Parker is currently accepting new patients.

Dr. Horsley attended the West Virginia School of Osteopathic Medicine, where he earned his degree in osteopathic medicine. He completed his residency at Geisinger Northeast General Surgery program in Wilkes Barre, Pa. He then continued his surgical training at Geisinger Medical Center in Danville, Pa., where he completed a fellowship in minimally invasive and bariatric surgery.|Dr. Horsley is a board certified in general surgery by the American Osteopathic Board of Surgery. He holds certifications by the American Society for Metabolic and Bariatric Surgery (ASMBS) for metabolic & bariatric surgery and by the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) for advanced GI MIS & bariatrics, and is verified by ASMBS/SAGES for bariatric endoscopy-bariatric endoscopy skill acquisition focused evaluation (BE-SAFE). Dr. Horsley is highly rated in 12 conditions, according to our data. His clinical expertise encompasses Obesity, Malnutrition, Hiatal Hernia, Gastric Bypass, and Endoscopy. Dr. Horsley is currently accepting new patients.

Anthony T. Petrick, MD, FACS, FASMBS, is a board-certified general surgeon specializing in esophageal and bariatric surgery. Dr. Petrick performs a number of advanced and specialized surgical procedures including advanced endoscopy, revisional bariatric surgery, laparoscopic gastric band (or “lap band”), gastric bypass, biliopancreatic diversion with duodenal switch and gastric sleeve. He also treats people for various conditions affecting the stomach and gastrointestinal (GI) system, including hiatal and paraesophageal hernia, achalasia and acid reflux (GERD).|Board-certified in general surgery, Dr. Petrick earned his medical degree from Georgetown University in Washington, D.C. He completed general surgery residency at Georgetown University Medical Center in Washington, D.C. He then completed a fellowships in Surgical Oncology at and Beth Israel Deaconess Medical Center in Boston and in Bariatric and Foregut surgery at the University of Pittsburgh Medical Center.|For the past 18 years, Dr. Petrick served as program director for the Geisinger bariatric and foregut surgical fellowship. He now serves as associate program director, acting as a mentor to bariatric surgery fellows. Dr. Petrick has a strong commitment to research in bariatric and foregut surgery and has authored more than 100 articles. Currently, he serves as chief quality officer for inpatient services at Geisinger and Director of the Division of Bariatric and Foregut surgery.|Dr. Petrick is an active member of the Society of Gastrointestinal and Endoscopic Surgeons and a fellow of the American College of Surgeons and American Society of Metabolic and Bariatric Surgeons. He chairs to Data and Quality Committee for the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program and also serves as an editorial board member for the journal Surgical and Obesity-Related Diseases and a columnist for Bariatric Times.|In his free time, Dr. Petrick serves on the board of education at St. Joseph School in Danville. He also coaches the Susquehanna Valley Stampede varsity and junior varsity ice hockey teams.|Clinical Focus: Bariatric Surgery|If you’re a provider who’d like to refer a patient, call our 24/7 referral line at 800-332-8901 or visit www.emr-link.com. Dr. Petrick is highly rated in 14 conditions, according to our data. His clinical expertise encompasses Obesity, Hiatal Hernia, Hernia, Gastric Bypass, and Endoscopy. Dr. Petrick is currently accepting new patients.