Dr. Mark E. Mahan

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, Hiatal Hernia, Malnutrition, 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.

Harshit S. Khara, MD, is an Interventional Gastroenterologist based at Geisinger Medical Center in Danville, PA.|Dr. Khara is an Associate Professor of Medicine at the Geisinger Commonwealth School of Medicine. He serves as the Director of Endoscopy; System Director of Interventional Endoscopy, Director of Endoscopic and Translational Research; Director of the Clinical Use Evaluation Committee; and System Director of Quality & Innovation. He is also the Research Director and Core faculty for the Gastroenterology Fellowship Program, as well as the Program Director for the Advanced Therapeutic Endoscopy Fellowship Program at the Center for Advanced Therapeutic Endoscopy at Geisinger, participating in the training and mentoring of advanced endoscopy and general gastroenterology fellows. Dr. Khara is also the Director of the National Pancreas Foundation Center at Geisinger.|He is involved in multi-center clinical research and quality improvement projects. Dr. Khara's clinical and research interests are in the field of interventional endoscopic ultrasound, ERCP, Barrett’s esophagus, third space endoscopy, endoscopic treatments for GERD, interventional EndoHepatology, and bariatric interventional endoscopy.|Dr. Khara earned his medical degree from Seth G.S. Medical College & K.E.M. Hospital in India then completed his Internal Medicine Residency at Drexel University College of Medicine-Saint Peter's University Hospital. He completed a Fellowship in Transplant Hepatology at the University of Nebraska Medical Center, a Fellowship in Gastroenterology at Yale University School of Medicine-Norwalk Hospital and a Fellowship in Advanced Therapeutic Endoscopy at Geisinger Medical Center.|Dr. Khara is certified in Gastroenterology by the American Board of Internal Medicine. Dr. Khara is highly rated in 26 conditions, according to our data. His clinical expertise encompasses Pancreatic Pseudocyst, Gastroesophageal Reflux Disease (GERD), Barrett Esophagus, Endoscopy, and Colonoscopy. Dr. Khara is currently accepting new patients.