Meet the Team

Bariatric Surgeon 

fischerLaura Fischer, MD, MS

Assistant Professor
Medical Director, Metabolic & Bariatric Surgery Program

Dr. Fischer is a board-certified surgeon specializing in advanced GI, minimally invasive, and bariatric surgery. In addition to weight loss surgery, she has clinical interest in benign and malignant conditions of the esophagus and stomach, as well as performing laparoscopic procedures of the spleen, adrenal gland, biliary tract, pancreas, small intestine, and abdominal wall hernias. She also specializes in robotic surgery.

Dr. Fischer’s areas of interest include treating high-risk bariatric patients and those who have had complications from prior bariatric surgery. She is active in multiple areas of research, but her main research interest is investigating the link between obesity and cancer. She also performs translational and clinical research in inflammation, gut hormones and the microbiome, laparoscopic and robotic education and simulation, as well as patient outcomes after weight loss surgery.                         

Dr. Fischer completed a fellowship in Minimally Invasive and Bariatric Surgery at the Oregon Health & Science University (OHSU, Portland OR.). She completed a general surgery residency and internship at the University of Wisconsin Hospital and Clinics, Madison, WI. She earned her medical degree at Columbia University College of Physicians and Surgeons, New York City, NY. She is member of the American Society for Metabolic and Bariatric Surgery (ASMBS).

Andrea Putthoff, APRN-CNP

Andrea has over 11 years of nursing experience in Intensive Care, Perioperative, Post-Operative and Emergency Care. She is nationally certified with both the American Nurses Credentialing Center (ANCC) and the American Association of Nurse Practitioners (AANP).

Andrea graduated from the University of Oklahoma Health Sciences Center with a Bachelor of Science degree in Nursing with Distinction. She received an Academic Achievement Award, Outstanding Graduating Student Award, Outstanding Clinical Nursing Practice Award and Outstanding Student Leadership Award while at OUHSC.  In addition, she earned a Master of Science ​degree in Nursing from the University of Cincinnati.

Andrea’s professional interests include exploring the relationships between obesity and mental health and obesity and hormone disorders; and how obesity affects overall quality of life. 

Program Coordinator

Susan Wegrzynski, RNSusan Wegrzynski, RN

Susan came to OU Physicians Bariatric Surgery Clinic from the Oklahoma State Department of Health.  As the Program Coordinator, Susan’s duties include managing quality improvement projects, assisting with research, providing education to patients and increasing community awareness of the benefits of bariatric surgery. 

Susan holds a Master of Science degree in Nursing from the University of Central Oklahoma where she was awarded the Distinguished Graduate Nursing Student Award.  She possesses 10 years of experience in public health nursing.  Her additional experience includes Inpatient and Home-Based Adolescent and Adult Psychiatric Nursing.  Prior to her employment with OU Physicians, Susan completed a fellowship in the Oklahoma Public Health Leadership Institute.  Her group project to encourage the consumption of water and to reduce the use of sugary drinks in the Oklahoma population became the Shape Your Future: Rethink Your Drink statewide media campaign. 

Behavioral Health

Maria Trapp, PhDMaria Trapp, PhD


Dr. Trapp did her undergraduate work at California State University, Los Angeles, CA. After moving to Oklahoma in 1981, she completed her graduate degrees, both Master’s and Doctorate, at the University of Oklahoma.  During her last year of graduate school, she chose to do her internship with veterans ​at the Dallas VA Medical Center.  After returning to Oklahoma, she worked for the Citizen Potawatomie Nation in Shawnee as the Director of Children’s Services in their Mental Health Unit.  In 2000, she began her private practice in Edmond, OK.  She has continuously worked for women, children, families and those who are members of under-served groups of our community. 

Dr. Trapp is published in the areas of depression and patterns of change.  She has taught at both the University of Oklahoma and the University of Central Oklahoma.  Dr. Trapp was a featured contributor on News Channel 4 every Monday on the 4:30 p.m. news from 2003 to 2007.  She has served as president of the Oklahoma Psychological Association.  She is also currently the Chairperson of the Oklahoma Commission on the Status of Women.  Dr. Trapp has worked with a wide variety of concerns and issues regarding mental health, but has a particular interest in depression, anxiety, issues regarding life changes and relationship dynamics.

Physical Therapy

Denise Bender, JD, PT, M.Ed.Denise Bender, JD, PT, M.Ed.

Licensed Physical Therapist

Dr. Bender is an Associate Professor at the University of Oklahoma Health Science Center (OUHSC) College of Allied Health and College of Medicine in the Department of Rehabilitation Sciences. She earned her Physical Therapy degree from St. Louis University, a Master in Education from Wayne State University, and a Law degree with Honors from the University of Maryland, Baltimore. Denise is a member of professional special interest groups, including Academy of Geriatric Physical Therapy, Academy of Education, and Cardiovascular and Pulmonary section. Her experience practice includes military and community settings, as well as a previous faculty appointment at the University of Maryland, Baltimore. In 2001, she joined the OUHSC Physical Therapy faculty and became Program Director for the Doctor of Physical Therapy Program in 2008. In 2012, she completed the APTA’s Educational Leadership Institute (ELI) fellowship program and became the Jill Pitman Jones Professor of Physical Therapy in 2016.  She is licensed as a physical therapist and an attorney in Oklahoma.


brownDianne Brown, MS RDN, LD, CDE

Dianne Brown is a Registered Dietitian for the OU Metabolic and Bariatric Surgery Program. She earned a Master of Science degree in Dietetic and Nutrition from the University of Kansas in Lawrence, KS. She is a Certified  Diabetes Educator. Her areas of expertise include hyperlipidemia, hypertension, weight management, and types 1, 2, and gestational diabetes. She has co-authored several books and has presented educational sessions to both the public and medical professionals. Ms. Brown is past-president of Oklahoma Dietetic Association and Western Oklahoma Diabetes Educators and is a member of The Academy of Nutrition and Dietetics (formerly the American Dietetic Association) and Diabetes Care and Education Practice Group. 

olsonChristine Olson, MS RD/LD

Christy Olson is a Registered Dietitian for the OU Metabolic and Bariatric Surgery Program. She graduated in 2001 with a Master of Science in Nutrition and Food Management from the University of Central Oklahoma. She is certified in both adult and pediatric weight management. Ms. Olson first worked as a Registered  Dietitian and Diabetes Educator for Indian Health Services for 8 years, providing diabetes education and developing and leading both adult and childhood obesity programs. Thereafter, she worked as a Bariatric Dietitian in Norman, Oklahoma, for 3 years before joining the team as a Registered Dietitian and Certified  Diabetes Educator at the Harold Hamm Diabetes Center in February 2011.