A member of our Neurology team, Maria Gonzales, FNP-C, is a nurse practitioner who works closely with neurologists and other clinical staff to assess, diagnose and treat patients with neurological conditions such as stroke, epilepsy, multiple sclerosis, Alzheimer’s disease and chronic headache. Born and reared in the Philippines, she earned her Bachelor of Science in Nursing before emigrating to the United States in 2005. She practiced 17 years in healthcare settings in New York. In 2017 she joined Trinity Health, where she cared for patients in the Emergency/Trauma Center before completing her Master of Science degree in Advanced Nurse Practice from Walden University, Minneapolis. Maria is certified by the American Academy of Nurse Practitioners. She enjoys traveling when she’s not taking care of patients.
Melissa Andreasen, FNP-C
A member of our pediatrics team, Melissa Andreasen, MSN, FNP-C, is a board-certified family nurse practitioner, dedicated to providing compassionate, evidence-based care to children and adolescents. A graduate of Minot State University, Melissa earned her Bachelor of Science in Nursing in 2013 and began her nursing career as an RN with Trinity Health. She served patients in the addiction services, intensive care, and same day surgery units before shifting her focus to advanced practice nursing. While pursuing a Master of Science in Nursing from the University of Cincinnati, she worked part time as a clinical nurse instructor with Dakota College at Bottineau. She completed her Family Nurse Practitioner training 2020 and joined a private primary care practice as a family care provider, helping pediatric, adult, and geriatric patients manage the full range of acute and chronic health conditions. Melissa is board certified by the American Association of Nurse Practitioners. She loves spending time with her two children when she’s not at work.
Joseph Stonehocker, CPNP-PC
Trinity Health is pleased to announce that Joseph Stonehocker, CPNP-PC, has joined our team of providers at Trinity Health Western Dakota in Williston. A board certified pediatric nurse practitioner, Joseph has spent the last three years serving the healthcare needs of Williston-area young people. He provides primary care to children ages 0 to 18, with an emphasis on general and acute pediatric care, annual well-child visits, and mental health support, including ADHD diagnosis and treatment. He’s also trained in various surgical procedures such as circumcision and tongue-tie correction. Originally from Canada, Joseph was reared in Edmonton, AB, and moved to the United States with his family at an early age. He graduated from Utah State University and earned both his Master of Science in Pediatric Nurse Practice and his Bachelor of Science in Nursing from UT Health San Antonio, part of the University of Texas system. A devoted husband and father, he and his wife have five children. They enjoy family time and attending youth sporting events.
William Sisa, MD
Dr. Sisa is a pediatrician, dedicated to providing holistic care that promotes the well-being of children, adolescents, and their families. He is specially trained to manage the full range of children’s physical, mental, and emotional health problems, including acute and chronic conditions, behavioral difficulties, and developmental disorders.
Dr. Sisa earned his Doctor of Medicine degree from St. George’s University School of Medicine, Grenada, and completed his pediatric residency at Lincoln Medical and Mental Health Center, a teaching hospital affiliated with Weill Cornell Medical College in New York City.
Dr. Sisa grew up in Ghana, where he won the Presidential Award for being the best student from one of the 10 regions in Ghana at the Junior High School level, after which he proceeded to Major in Science at the best high schools in Ghana. Upon completion of high school, he started a remedial school in his hometown which is currently a high school in Ghana.
He proceeded to the University of Ghana where he majored in Chemistry. Upon arrival in the USA, he worked as a quality control chemist at NicePak PDI helping to develop some of the HPLC methods used to test the Super Sani Wipe the most popular hospital disinfectant used in hospitals in the USA. Dr. Sisa was pursuing a graduate Studies in Biochemistry at The City University of NY before he decided to pursue medicine at the St. George’s University School Medicine.
During clinical years in NYC, he got interested in teaching and mentoring of high school students in the science field, and completed several hours of volunteer work teaching. During residency, he participated in various research projects and had one of his research topics presented at the Society for Academic Emergency Medicine (SAEM) 2020 Conference in Washington, DC.
He loves driving, playing volleyball, and soccer.
Anthony Udekwe, MD
Dr. Udekwe (Oo-dek-way) specializes in caring for children of all ages – from newborn to adolescent. He is experienced in managing a wide variety of problems ranging from infection and illness, to chronic conditions as well as developmental problems. He provides immunizations and regular checkups to help keep children healthy. A graduate of the University of Nigeria, Dr. Udekwe completed his residency in pediatrics at Children’s National Center and Howard University Hospital, both located in Washington, D.C. He is certified in Advanced Pediatric Life Support and Neonatal Resuscitation.
Mary Sadler, FNP-C
A nurse practitioner in Trinity’s Neurology Department, Mary Sadler, FNP-C, works closely with neurologists and other clinical staff to assess, diagnose and treat patients with neurological illnesses and injuries. She earned her Bachelor of Science in Nursing in 1998 from Minot State University and practiced 10 years with Trinity Health in the Rehabilitation, Ortho/Neuro and Emergency/Trauma departments. In 2010 she received her Master of Science/Family Nurse Practitioner degree from the University of Mary in Bismarck. Since then she has served patients in family practice and emergency settings, most recently serving as an Occupational Health/Family Practice nurse practitioner with Sanford Health. She’s a member of the American Academy of Nurse Practitioners, the North Dakota Nurse Practitioners Association, the American Academy of Neurology and the American College of Occupational and Environmental Medicine.
Diana Peterson, MD
A board certified pediatrician, originally from New Philadelphia, Ohio, Dr. Peterson earned her Doctor of Medicine degree from The Ohio State University College of Medicine and completed her internship and residency at Keesler Medical Center, Biloxi, Mississippi. She joined Minot Air Force Base’s 5th Medical Group as a staff pediatrician. She served as Chief of Pediatrics at the base hospital prior to joining Trinity Medical Group. She’s a Diplomat of the American Board of Pediatrics.
Friday Osuala, MD
Dr. Osuala is a pediatrician specially trained to manage the full range of physical, mental, and emotional health problems of children of all ages, including infections, injuries, chronic conditions, behavioral difficulties and developmental disorders. A graduate of the University of Nigeria College of Medicine, he worked as a general pediatrician at Tobago Regional Hospital in the West Indies for five years, where he provided outpatient and inpatient care for a Level 2 nursery and pediatric emergency room. He completed residency training in Pediatric Medicine at the Pediatric Department of Woodhull Medical Center, Brooklyn, NY.
Steven Mattson, MD
Steven R. Mattson, M.D. is a board certified internist and pediatrician. A graduate of the University of North Dakota, he received his medical degree from Michigan State University and completed his residency at Mayo Graduate School of Medicine and the University of North Dakota Affiliated Hospitals. He has practiced in Minot since 1988. Mattson is a fellow of the American Academy of Pediatrics and the American College of Physicians.
Rosina Medel, MD
Rosina Medel, MD, is a neurologist board certified by the American Board of Psychiatry and Neurology. Dr. Medel provides specialized care for patients dealing with the full spectrum of neurological disorders affecting the brain, nervous system, peripheral nerves and muscles. She received her early medical training in the Philippines, earning a nursing degree and later a medical doctorate from the University of Perpetual Help System. She migrated to the United States, where she completed a preliminary residency in Internal Medicine at Nassau University Medical Center, East Meadow, NY. She fulfilled her Neurology residency and performed a fellowship in Clinical Neurophysiology at JFK Medical Center in Edison, NJ, where she served as chief resident her final year and earned numerous awards for academic and clinical excellence. Dr. Medel is a member of the American Academy of Neurology.