Our Providers
Colorectal Surgeons
Daniel Coffey, MD
Board Certifications
- Board Certified, General Surgery
- Board Certified, Colon and Rectal Surgery
Education
- 1995 Graduated from Vanderbilt University
- 1999 Medical Degree from University of Louisville
- 1999 – 2004 General Surgery Residency at Michigan State University in Lansing, Michigan
- 2003 – 2004 Chief Resident in Integrated Residence in General Surgery at Michigan State University
- 2004 – 2005 Resident in Colon and Rectal Surgery at Carle Foundation Hospital
Professional Memberships
- American Society of Colon and Rectal Surgeons
- Michigan Society of Colon and Rectal Surgeons
- American College of Surgeons
- Michigan State Medical Society
- Ingham County Medical Society
Activities and Honors
- Clinical Assistant Professor, Department of Surgery, Michigan State University
- On staff at Sparrow Hospital and McLaren Hospital
Lucas Julien, MD
Board Certifications
- Board Certified, General Surgery
- Board Certified, Colon and Rectal Surgery
Education
- 2000 Graduated from Lyman Briggs College at Michigan State University in East Lansing, Michigan
- 2004 Medical Degree from Michigan State University College of Human Medicine
- 2004 – 2009 General Surgery Residency at Michigan State University in Lansing, Michigan
- 2008 – 2009 Chief Resident in General Surgery at Michigan State University
- 2009 – 2010 Research Fellowship in Colon and Rectal Surgery
- 2010 – 2011 Clinical Fellowship in Colon and Rectal Surgery at Creighton University
Professional Memberships
- American Society of Colon and Rectal Surgeons
- Michigan Society of Colon and Rectal Surgeons
- American College of Surgeons
Activities and Honors
- Clinical Assistant Professor, Department of Surgery, Michigan State University
- Past Chair of Surgery Department, Sparrow Hospital
- On staff at Sparrow Hospital and McLaren Hospital
Research and Publications
Multiple scientific publications and co-author of a chapter in Shackelford’s Surgery of the Alimentary Tract, 7th edition textbook.
Razvan Opreanu, MD
Board Certifications
- Board Certified, General Surgery
- Board Certified, Colon and Rectal Surgery
Education
- 2004 Medical Degree from Ovidius University
- 2004 Master of Science in Gastroenterology, Ovidius University
- 2009 – 2015 General Surgery Residency at Michigan State University
- 2015 – 2016 Fellowship in Colon and Rectal Surgery, St. Vincent Hospital
Professional Memberships
- American Society of Colon and Rectal Surgeons
- American Society of Colon and Rectal Surgeons Residents Committee
- American College of Surgeons
Activities and Honors
- Clinical Assistant Professor, Department of Surgery, Michigan State University
- Past Chair of Surgery Department, Sparrow Hospital
- On staff at Sparrow Hospital and McLaren Hospital
Research and Publications
Gastroenterologists
Scott Plaehn, DO, FACOI
Dr. Plaehn is a medical graduate from the Chicago College of Osteopathic Medicine in Illinois. He performed his Internship and Residency at Metropolitan Hospital in Grand Rapids, Michigan an affiliate of Michigan State University. He then went on to Botsford General Hospital in Farmington Hills, Michigan where he completed his Fellowship in Gastroenterology. Dr. Plaehn is board certified in both Internal Medicine and Gastroenterology. He has been practicing in the Lansing area since 1996.
Albert Ross, MD
Dr. Ross received his medical degree from Washington University in St. Louis, Missouri where he graduated with honors. His Internship and Residency were performed at the University of Chicago Hospital and his Fellowship was completed at Froedtert Memorial Lutheran Hospital in Milwaukee, Wisconsin. He is board certified in both Internal Medicine and Gastroenterology. Dr. Ross has been practicing in the Lansing area since 1995.
John Walling, Jr., DO, FACOI
Dr. Walling received his medical degree from the University of Health Science in Kansas City, Missouri. He completed his Internship at Mt. Clemens General Hospital. His Residency training and Fellowship in Gastroenterology were done at Botsford General Hospital in Farmington Hills, Michigan. Dr. Walling is board certified in both Internal Medicine and Gastroenterology. He has been practicing in the Lansing area since 1992.
Siaka Yusuf, MD
Dr. Yusuf is originally from Nigeria where he obtained a Bachelor of Medicine from the University of Ilorin, Nigeria. He then came to the United States to do his Internship and Residency at Morehouse School of Medicine in Atlanta, Georgia. Dr. Yusuf then went on to New York to complete his Fellowship in Gastroenterology at State University of New York. He was a Medical Officer at Mutare General Hospital in Zimbabwe as well as an Assistant Clinical Instructor in New York. He is board certified in Gastroenterology and Internal Medicine. He joined Digestive Health Institute in December of 2000.
Dorian Jones, MD
Dr. Dorian Jones was born in Detroit, Michigan, and grew up in Romulus and Canton, Michigan. From an early age, he had a passion for science and helping others. He graduated from Plymouth Salem High School with distinction. He received a Bachelor of Arts in Chemistry from Kalamazoo College in Kalamazoo, Michigan. He also completed a minor in Biology with concentrations in molecular biology and biochemistry. His senior thesis was in synthetic organic chemistry. During his time at Kalamazoo College, he studied abroad in Madrid, Spain, and served on many committees. Afterward, he received his Doctor of Medicine (M.D.) from Tufts University School of Medicine in Boston, Massachusetts. Next, he completed internal medicine training at the Cleveland Clinic Foundation in Cleveland, Ohio, and served an additional year as a Chief Medical Resident. During this time, he completed training in process improvement, and participated in training in Lean and Six Sigma. He completed Gastroenterology and Hepatology Fellowship at Henry Ford Hospital in Detroit, Michigan. During training, he researched and published in inflammatory bowel disease, process improvement, patient safety, and liver disease. Later, he moved to Okemos with his wife and daughter, and joined the Digestive Health Institute. Since his arrival in 2018 he has enjoyed seeing patients in Gastroenterology and Hepatology, and servicing the community. In addition to his work in medicine and research, he enjoys sports, running, weightlifting, photography, reading, and cooking.
Jannel Lee-Allen, MD
Tadd Hiatt, MD
Physician Assistants
Jonathan Thelen, PA-C
Jonathan Thelen PA-C obtained his Bachelor of Science Degree in human biology with a specialization in health promotion from Michigan State University in May 2007. He then attended Central Michigan University and graduated with a Master’s Degree and Certification in Physician Assistant Studies in July 2009. He has been with Digestive Health Institute since 2009. He also holds the position of the Mid-Level Provider Coordinator.
Callie Hart, PA-C
Callie received her Bachelor of Arts in Human biology with high honors from the University of Michigan. She completed her graduate studies at Central Michigan University, earning her Masters in Science- Physician Assistant Studies in October 2020. Callie joined the Digestive Health Institute team in August 2021.
Brooke Janke, PA-C
Brooke Janke, PA-C obtained her undergraduate degree with a major in biomedical sciences from Central Michigan University in 2014. She earned her Master of Physician Assistant Studies from Grand Valley State University in 2017. She is board certified with the National Commission on Certification of Physician Assistants and joined the Digestive Health Institute team in 2018.
Andrea Koerner, RD, PA-C
Andrea Koerner PA-C obtained her Bachelor of Science Degree in Dietetics from Central Michigan University. She then completed the University of Michigan Health System Dietetic Internship which enabled her to become a Registered Dietitian. She then attended Eastern Michigan University and graduated with a Master’s Degree and Certification in Physician Assistant Studies in July 2019. She has been with Digestive Health Institute since 2021.
Don Laird, PA-C
Don Laird PA-C achieved his Bachelor of Science Degree in human biology from Michigan State University in May 2007. He continued his graduate studies at Central Michigan University and earned his Masters degree and Certification in Physician Assistant Studies in July 2009. He has been with Digestive Health Institute since 2009.
Scott Zeilstra, PA-C
Scott Zeilstra PA-C achieved his Master’s Degree from Central Michigan University Physician Assisting Program and joined Digestive Health Institute after graduation in 2013. He is certified by the National Commission on Certification of Physician Assistants.
Khadra Mohamed, RDMS, PA-C
Scott Zeilstra PA-C achieved his Master’s Degree from Central Michigan University Physician Assisting Program and joined Digestive Health Institute after graduation in 2013. He is certified by the National Commission on Certification of Physician Assistants.
Leslie Thelen, PA-C
Scott Zeilstra PA-C achieved his Master’s Degree from Central Michigan University Physician Assisting Program and joined Digestive Health Institute after graduation in 2013. He is certified by the National Commission on Certification of Physician Assistants.
