Our Team of Bariatric Surgery Experts

The Center for Bariatric Surgery is composed of a multidisciplinary team of bariatric specialists who provide personalized treatment, committing to years of follow-up care and supporting your effort to maintain a healthy weight, while meeting your nutritional needs.

The process you will follow involves several phases:
  • Before surgery, our team of specialists, including a surgeon, nutritionist, radiologist, pulmonologist, cardiologist, psychiatrist and members of the nursing staff, will perform comprehensive medical exams and evaluations. You will also be asked to attend intensive educational classes and support group programs to learn what to expect during and after surgery.
  • During the procedure, board-certified surgeons trained in advanced laparoscopic surgery and bariatric care will work closely with anesthesiologists and highly trained operating room staff who are familiar with the special needs of bariatric patients.
  • After surgery, nurses trained in post-bariatric surgical care will work to prevent and manage possible complications. The surgeon, bariatric nurses, and nutritionist will follow you carefully throughout recovery.
  • During and after your recovery, you must commit to making profound lifestyle changes. To help meet this challenge successfully and safely, you will be closely monitored for nutritional deficiencies and will receive free counseling to help you manage post-operative dietary requirements. You will continue to attend our free support group meetings.

In addition to the help you will receive from the bariatric team, you also have available the expertise of our weight management programs to provide additional, ongoing help.

The Miriam Hospital is known for our highly successful behavioral medicine weight programs, which have helped many people take control of their weight and health.

Chief, Minimally Invasive and Bariatric Surgery

Siva Vithiananthan, MD chief of minimally invasive and bariatric surgery at the Center for Bariatric Surgery, leads the surgical team. Vithiananthan specializes in laparoscopic surgical procedures, both bariatric and non-bariatric, and has many years' experience in bariatric surgery. He is also an associate professor of surgery (clinical) at The Warren Alpert Medical School of Brown University. His main research focus is on advanced surgical techniques and the metabolic and physiological effects of weight loss surgery.

Vithiananthan received his medical degree from Columbia University College of Physicians and Surgeons in New York, New York. He completed his residency at Baystate Medical Center in Springfield, Massachusetts, and fellowships at New York Presbyterian Hospital in New York, New York, and the University of Connecticut School of Medicine/Hartford Hospital in Hartford, Connecticut.

Pediatric Surgeon, Adolescent Bariatric Surgeon

Elizabeth J. Renaud, MD, is a surgeon at Rhode Island and The Miriam hospitals. She specializes in pediatric surgery and performs procedures at Hasbro Children’s Hospital. At Albany Medical Center, she was a pediatric trauma program director, associate professor of surgery and associate surgical residency program director. She held similar leadership positions at the University of Massachusetts Memorial Medical Center between 2009 and 2011. She was honored with the New York Rising Stars award in 2013.

Dr. Renaud’s research interests include trauma, outcomes research, minimally invasive surgery, and adolescent bariatric surgery. Her work has been published in several peer-reviewed journals and book chapters, such as the Journal of Pediatric Surgery and the Journal of Trauma and Acute Care Surgery. She has presented her research on topics such as endometrial cancer, appendicitis and childhood obesity. She is a member of the American Society for Metabolic and Bariatric Surgery, the Pediatric Trauma Society and the American Pediatric Surgical Association.

Senior Vice President for Medical Affairs and Chief Medical Officer, The Miriam Hospital

G. Dean Roye, MD, a surgeon specializing in laparoscopic surgical procedures (both bariatric and non-bariatric), is senior vice president for medical affairs and chief medical officer at The Miriam Hospital. He is also an assistant professor of surgery (clinical) at The Warren Alpert Medical School of Brown University.

Roye received his medical degree from the University of Miami in Miami, Florida. He completed his residency in general surgery at the University of Alabama School of Medicine in Birmingham, Alabama and a fellowship in laparoscopic surgery at The Warren Alpert Medical School of Brown University and Rhode Island Hospital in Providence, Rhode Island.

Bariatric Surgeon

Beth Ann  Ryder, MD is a surgeon specializing in bariatric surgery, surgical education, and emerging technologies for minimally invasive surgery. She is also an assistant professor of surgery at The Warren Alpert Medical School of Brown University.

Ryder received her medical degree from Tufts University School of Medicine in Boston, Massachusetts. She completed her residency in general surgery and a fellowship in minimally invasive surgery at Brown Medical School and Rhode Island Hospital in Providence, Rhode Island.

Bariatric Surgeon

Todd Stafford, MD, is a surgeon specializing in laparoscopic surgical procedures, both bariatric and non-bariatric. He is also an assistant professor of surgery (clinical) at The Warren Alpert Medical School of Brown University.

Stafford received his medical degree from Temple University School of Medicine, in Philadelphia, Pennsylvania. He completed his residency in general surgery and a fellowship in laparoscopic surgery at The Warren Alpert Medical School of Brown University and Rhode Island Hospital in Providence, Rhode Island.

Lisha Andrew, RD, LDN
Bariatric Dietitian

Lisha Andrew, RD, LDN, is a bariatric dietitian at the Center for Bariatric Surgery at The Miriam Hospital. She received her bachelor of science in food and nutrition/dietetics at Framingham State University and is currently completing her master of science in nutrition and health promotion at Simmons University in Boston.

As a bariatric dietitian, she provides nutrition evaluation and weight management nutrition counseling for patients prior to bariatric surgery, as well as medical nutrition therapy and counseling for postoperative patients. She participates in the bariatric support groups to include periodic nutrition and behavior change education. Her primary focus is to help patients set individualized, realistic goals for permanent lifestyle changes to optimize postoperative outcomes and attainment of optimal weight loss and health.

Kellie Armstrong, MS, RN, CBN
Program Manager

Kellie Armstrong, MS, RN, CBN, is the program manager of the Center for Bariatric Surgery at The Miriam Hospital. She received her bachelor of science in nursing from Rhode Island College and her master of science in nursing from the University of Rhode Island. She is certified in nursing administration and the disease process of obesity. As program manager, she oversees the day-to-day management of the Bariatric Surgery Program and serves as liaison and care coordinator between the hospital, surgical program, and other aspects of the Multidisciplinary Bariatric Surgery Program.

Viviane Fornasaro-Donahue, MS, RD, LDN
Registered Dietitian

Viviane Fornasaro-Donahue, MS, RD, LDN, is a registered dietitian with the Center for Bariatric Surgery at The Miriam Hospital. She received her master of science in nutrition and food science and completed her dietetic internship at the University of Rhode Island in Kingston. Her research on baby formula costs motivating prolonged breastfeeding was published in the Journal of Nutrition Education and Behavior in 2014. She speaks Portuguese, Spanish and English.

Alanna Salvas
Program Liason

Alanna Salvas is the program liaison at the Center for Bariatric Surgery at The Miriam Hospital. Alanna acts as a liaison between patients, bariatric and urologic surgery clinical offices, dietitians and other Lifespan entities for all aspects of the Center for Bariatric Surgery program. She manages the Center for Bariatric Surgery and Minimally Invasive Urology Institute hotlines, coordinates patient referral, referral data, community physician referrals, and resources into a seamless model of access and care.

Sara Stiles, RD, CSOWN, LDN
Lead Bariatric Dietitian

Sara Stiles, RD, CSOWN, LDN, is the lead bariatric dietitian at the Center for Bariatric Surgery at The Miriam Hospital. She received her bachelor of science in food and nutrition and dietetics from Framingham State University in Massachusetts and completed her dietetic internship with Sodexo and Southcoast Health. She also maintains additional credentialing as a certified specialist in obesity and weight management. She is passionate about helping each patient become successful in improving their quality of life through various lifestyle changes.