Your support team.

Grinnell Center of Excellence Staff and Affiliated Staff


David D. Coster, MD, Medical Director of Grinnell Bariatrics and Bariatric Surgeon - Grinnell Bariatrics

Dr. Coster leads the bariatric program with more than 20 years of experience caring for bariatric patients. He performs open and laparoscopic gastric bypass, laparoscopic sleeve gastrectomy, and complex revision procedures. Dr. Coster is experienced in all areas of general surgery and has a special interest in skin reconstruction after weight-loss from surgery for obesity. Dr. Coster has two board certifications: General Surgery and Critical Care.


Nicholas J. Kuiper, DO, Bariatric Surgeon - Grinnell Bariatrics

Dr. Kuiper joined Surgical Associates, LLP, in July 2010. As a general surgeon, Dr. Kuiper provides expert surgical care for a broad range of bariatric and general surgical problems. He is well-trained in all types of laparoscopic minimally invasive procedures including: DaVinci Robotic Surgery and SILS (single incision laparoscopic surgery). Dr. Kuiper is board certified in General Surgery. 


Mathew W. Severidt, DO, Bariatric Surgeon - Grinnell Bariatrics

Dr. Severidt joined Grinnell Bariatrics and Surgical Associates in July 2012. Dr. Severidt provides expert care in general surgery, minimally invasive surgery, and bariatric procedures including laparoscopic sleeve gastrectomy, laparoscopic gastric bypass, and revision procedures. Dr. Severidt has a special interest in Critical Care Medicine and Surgery. Dr. Severidt is board certified in General Surgery.


Stefanie H. Noun, PA-C, Bariatric Program Director - Grinnell Bariatrics

Ms. Noun is a board-certified physician assistant with extensive experience in medicine and psychiatric care. Noun directs and integrates the bariatric program for Surgical Associates and Grinnell Regional Medical Center. Noun sees patients in the office and hospital. She provides medical care, education, and long term follow-up for our patients. 


Jarrod Phelps, PA-C - Grinnell Bariatrics

Mr. Phelps is a board-certified physician assistant with experience in bariatric and general surgery procedures. He assists the surgeons in the operating room during bariatric surgeries. He also provides follow up with patients in the hospital and office. 


Bridget Baechtel, LISW - Grinnell Bariatrics

Ms. Baechtel provides group, individual, and family psychotherapy for the bariatric program as well for the local and state wide community. She received her undergraduate degree and her master’s degree in Social Work from the University of Iowa. Baechtel belongs to the Academy for Eating Disorders, the National Association of Social Workers, and the the Post Traumatic Stress Disorder Academy.


Jamie Brennan - Grinnell Bariatrics

Ms. Brennan graduated from Kirkwood Community College with a degree in health information technology and medical coding. She has been at Surgical Associates since 2010. She works closely with the surgeons, healthcare professionals, and insurers both pre and post operatively to prepare patients for surgery. 


Sammi Bryan, RN - Grinnell Bariatrics

Ms. Bryan graduated from Marshalltown Community College with an associate’s degree in nursing. Bryan has worked as a registered nurse since 1985. She has been employed with Surgical Associates since 1990.



Ronald B. Collins, MD, Hospitalist - Affiliated Staff

Dr. Collins is the hospitalist on the Bariatric Review Commitee As an internal medicine specialist, Dr. Collins, along with his Internal Medicine colleagues, provides diagnostic and treatment care to bariatric patients admitted to the medical center. 


Michelle Rebelsky, MD, FAAFP Pediatric Medical Director for Bariatrics - Affiliated Staff

Dr. Rebelsky is the pediatric medical advisor for the Bariatric Center of Excellence. She provides comprehensve medical care for pediatric patients of the program. 


Elaine Hammes, MS, RD, LD, Dietitian - Affiliated Staff

Ms. Hammes specializes in weight loss, bariatric surgery and heart health. She has a special interest in incorporating nutrition into overall wellness and health promotion. 


Chad Nath, Director of Wellness & Fitness - Affiliated Staff

Mr. Nath graduated from Buena Vista University with a BA in education and athletics in 1996. Mr. Nath is responsible for developing and directing fitness and wellness programs and services to meet the needs of the community. 


Emily Vesely, RN, Care Coordinator - Affiliated Staff

Ms. Vesley ensures that the patient has all that they need before and after surgery for a safe and successful recovery. She has nursing experience in medical/surgical, obstetrics, intensive care unit and surgery. 


Linda Romero, LISW, Social Worker - Affiliated Staff

Ms. Romero helps patients with issues regarding the adjustment to weight loss and the impact on emotional and social well-being.


Lynn Stone Moorman, RN - Grinnell Bariatrics

Ms. Stone Moorman graduated from Marshalltown Community College with an associate’s degree in nursing. She has worked in surgery since 2006. She has been employed with Surgical Associates since April 2011.


Stacey Simbro, RN - Grinnell Bariatrics

Ms. Simbro graduated from Mercy College of Health Science with an associate’s degree in nursing in 2005. She has worked in surgery since 2005. She has been employed with Surgical Associates since September 2011.