• Experience, talent, and impeccable training distinguish our team.

  • Nathaniel T. Dew, MD, FACS
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    Nathaniel T. Dew, MD, FACS

    General and Vascular Surgery

    Professional Organizations

    American Medical Association
    Fellow, American College of Surgeons
    Society of Laparoendoscopic Surgeons
    Indiana State Medical Association
    Society of American Gastrointestinal Endoscopic Surgeons
    Christian Medical & Dental Associations

    Board Certification

    The American Board of Surgery

    Education

    Bachelor of Arts, Taylor University, Upland, Indiana
    Doctor of Medicine, Indiana University School of Medicine, Indianapolis, Indiana

    Internship

    Baylor University Medical Center, Dallas, Texas

    General Surgery Residency

    Baylor University Medical Center, Dallas, Texas

    Dr. Nathaniel Dew is a board-certified surgeon specializing in minimally invasive surgery of the chest, abdomen, pelvis, vascular system and endocrine system, as well as wounds. He utilizes the latest medical technologies, such as endovascular and laparoscopy, to improve outcomes and reduce recovery times for his patients.

    Dr. Dew is uniquely qualified to diagnose health issues and recommend the most appropriate course of treatment. In some cases, he may prescribe preventive steps to help patients maintain a healthy and active lifestyle without surgical intervention.

  • Daniel A. Diener, MD, FACS
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    Daniel A. Diener, MD, FACS

    General and Vascular Surgery

    Professional Organizations

    American Medical Association
    Fellow, American College of Surgeons
    Society of Laparoendoscopic Surgeons
    Indiana State Medical Association
    Society of American Gastrointestinal Endoscopic Surgeons
    Mennonite Health Fellowship

    Board Certification

    The American Board of Surgery

    Education

    Bachelor of Arts, Goshen College, Goshen, Indiana
    Doctor of Medicine, University of Puerto Rico School of Medicine, Rio Piedras, Puerto Rico

    Internship

    Baylor University Medical Center, Dallas, Texas

    General Surgery Residency

    Baylor University Medical Center, Dallas, Texas

    Dr. Daniel Diener is a board-certified surgeon specializing in minimally invasive surgery of the chest, abdomen, pelvis, vascular system and endocrine system, as well as wounds. He utilizes the latest medical technologies, such as endovascular and laparoscopy, to improve outcomes and reduce recovery times for his patients.

    As a dedicated physician, Dr. Diener is uniquely qualified to diagnose health issues and recommend the most appropriate course of treatment. In some cases, he may prescribe preventive steps to help patients maintain a healthy and active lifestyle without surgical intervention.

  • Kevin D. Gerig, MD, FACS
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    Kevin D. Gerig, MD, FACS

    General and Vascular Surgery

    Professional Organizations

    American Medical Association
    Fellow, American College of Surgeons
    Society of Laparoendoscopic Surgeons
    Indiana State Medical Association
    Society of American Gastrointestinal Endoscopic Surgeons

    Board Certification

    The American Board of Surgery

    Education

    Bachelor of Arts, Goshen College, Goshen, Indiana
    Doctor of Medicine, Indiana University School of Medicine, Indianapolis, Indiana

    Internship

    Akron City Hospital, Akron, Ohio

    General Surgery Residency

    Akron City Hospital, Akron, Ohio

    Dr. Kevin Gerig is a board-certified surgeon specializing in endoscopy of the colon and upper gastrointestinal tract. He utilizes the latest medical technologies, such as endovascular, to improve outcomes and reduce recovery times for his patients.

    With nearly three decades of experience, Dr. Gerig constantly seeks out the latest surgical advancements to provide his patients with the most informed medical care possible. In some cases, he may prescribe preventive steps to help patients maintain a healthy and active lifestyle without surgical intervention.

  • Winston C. Gerig, MD, FACS
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    Winston C. Gerig, MD, FACS

    General, Vascular and Bariatric Surgery

    Professional Organizations

    American Medical Association
    Fellow, American College of Surgeons
    American Society of Bariatric Surgeons
    Indiana State Medical Association
    Society of American Gastrointestinal Endoscopic Surgeons

    Board Certification

    The American Board of Surgery

    Education

    Bachelor of Arts, Goshen College, Goshen, Indiana
    Doctor of Medicine, Indiana University School of Medicine, Indianapolis, Indiana

    Internship

    Akron City Hospital, Akron, Ohio

    General Surgery Residency

    Akron City Hospital, Akron, Ohio

    Dr. Winston Gerig is a board-certified surgeon who has received advanced training in general, laparoscopic and bariatric surgery, allowing him to perform a wide range of surgical procedures. His special interests include advanced laparoscopic surgery of the foregut (esophagus and stomach) resulting in specialties involving laparoscopic acid reflux surgery and laparoscopic bariatric surgery (Roux-en-Y gastric bypass, sleeve and revisional surgeries).

    For over 20 years, Dr. Gerig has been a compassionate physician who believes that treatment doesn’t end after surgery. He believes patients deserve encouragement and emotional support to make them feel more comfortable with surgery and less apprehensive about their outcomes.

  • John C. Martens, MD, FACS
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    John C. Martens, MD, FACS

    General and Vascular Surgery

    Professional Organizations

    American Medical Association
    Fellow, American College of Surgeons
    Society of Laparoendoscopic Surgeons
    Indiana State Medical Association
    Society of American Gastrointestinal Endoscopic Surgeons

    Board Certification

    The American Board of Surgery

    Education

    Bachelor of Arts, Bluffton College, Bluffton, Ohio
    Doctor of Medicine, Indiana University School of Medicine, Indianapolis, Indiana

    Internship

    St. Mary’s Hospital, Grand Rapids, Michigan

    General Surgery Residency

    Blodgett Memorial Hospital, Grand Rapids, Michigan

    Dr. John Martens is a board-certified surgeon skilled in the latest medical technologies, such as endovascular and laparoscopy, to improve outcomes and reduce recovery times for his patients. His specialties include minimally invasive surgery of the chest, abdomen, pelvis, vascular system and endocrine system, as well as wounds. His 20-plus years of experience uniquely qualifies him to diagnose medical issues and recommend appropriate treatment for his patients, which may or may not include surgery.

    Dr. Martens has served as a missionary in Cambodia and Congo as part of his commitment to improving the health of all who need it.

  • Denise Clemens Murphy, MD, FACS
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    Denise Clemens Murphy, MD, FACS

    General, Vascular and Bariatric Surgery

    Professional Organizations

    American Medical Association
    Fellow, American College of Surgeons
    American Society of Bariatric Surgeons
    Association of Women Surgeons
    Mennonite Medical Association
    Society of Laparoendoscopic Surgeons
    Indiana State Medical Association

    Board Certification

    The American Board of Surgery

    Education

    Bachelor of Arts, Goshen College, Goshen, Indiana
    Doctor of Medicine, Indiana University School of Medicine, Indianapolis, Indiana

    Internship

    Summa Health System, Akron, Ohio

    General Surgery Residency

    Summa Health System, Akron, Ohio

    Dr. Denise Clemens Murphy is a board-certified surgeon dedicated to helping people improve their quality of life. As a highly skilled surgeon, she specializes in laparoscopic Roux-en-Y gastric bypass, sleeve gastrectomy, adjustable gastric band and revisional surgery for weight loss.

    In addition to Dr. Murphy’s bariatric surgery expertise, she is also trained in minimally invasive surgery of the chest, abdomen, pelvis, vascular system and endocrine system.

  • Mark R. Ranzinger, MD, FACS
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    Mark R. Ranzinger, MD, FACS

    General and Vascular Surgery

    Professional Organizations

    American Medical Association
    American College of Surgeons
    Society of American Gastrointestinal Endoscopic Surgeons

    Board Certification

    The American Board of Surgery
    National Board of Examiners
    Certificate Minimally Invasive Surgery

    Education

    Bachelor of Arts, Walla Walla College, Walla Walla, Washington
    Master of Public Health, Loma Linda University School of Public Health, University of East Africa Campus, Baraton, Kenya
    Doctor of Medicine, Loma Linda University School of Medicine, Loma Linda, California

    Internship

    Wright State University, Dayton, Ohio

    General Surgery Residency

    Wright State University, Dayton, Ohio

    Dr. Mark Ranzinger is a board-certified surgeon with an emphasis on minimally invasive surgery. His extensive experience includes laparoscopic approaches for benign conditions such as gastroesophageal reflux, paraesophageal hernias, achalasia, splenic diseases and hernias, as well as certain cancers of the pancreas, adrenal glands and colon.

    Dr. Ranzinger has served as medical director of two African hospitals. His works have been published in Journal of the American College of Surgeons, Southern Medical Journal and The American Surgeon.

  • Kristan Rheinheimer, MSN, FNP-BC
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    Kristan Rheinheimer, MSN, FNP-BC

    Nurse Practitioner

    Professional Organizations

    American Academy of Nurse Practitioners
    Oncology Nursing Society

    Board Certification

    Family Nurse Practitioner, Oncology Nursing Society (ONS)
    Advanced Oncology Certified Nurse Practitioner, Oncology Nursing Society (ONS)

    Education

    Master of Science in Nursing, University of Saint Francis, Fort Wayne, Ind.
    Bachelor of Science in Nursing, University of Saint Francis, Fort Wayne, Ind.

    Kristan Rheinheimer is a certified nurse practitioner. Her extensive medical experience includes administering therapeutic treatments, educating patients, and leading patient support groups.

    Kristan works closely with the surgeons at Gerig Surgical Associates to prepare patients before surgery and coordinate their care following surgery. In addition, she enjoys providing health and wellness education to underserved populations in the community.