Dr. Michael Zehnpfennig, MD

Dr. Michael Zehnpfennig and Montana Colon have served patients throughout Missoula and Western Montana since 2020. We are pleased to announce the relocation of the practice to Bozeman, where Dr. Zehnpfennig will partner with Bozeman Health Deaconess Regional Medical Center.

This transition will expand access to fellowship-trained colorectal care for patients throughout Central and Southwest Montana. Patients undergoing colon and rectal surgery will also have access to the Intuitive da Vinci 5 robotic surgical system, the newest generation of robotic surgical technology.

Michael Zehnpfennig, MD, is a fellowship-trained colon and rectal surgeon providing advanced, patient-focused care in Bozeman, Montana. He treats colon and rectal cancer, diverticulitis, inflammatory bowel disease, rectal prolapse, complex anal fistulas, hemorrhoids, anal fissures, and other disorders of the colon, rectum, and anus. His goal is to ensure that Montanans can receive specialized colorectal care without leaving the state.

Dr. Zehnpfennig graduated with honors from Wayne State University School of Medicine in Detroit, Michigan, in 2006. He then completed his general surgery internship and residency at Wayne State University and began practicing as a general surgeon in Montana in 2011.

During his early years in practice, Dr. Zehnpfennig recognized that many Montanans with complex colon and rectal conditions had to travel out of state for subspecialty care. To address that need, he completed a fellowship in minimally invasive colon and rectal surgery at the University of Texas McGovern Medical School in Houston under the guidance of Dr. Eric Haas, a nationally recognized leader in minimally invasive colorectal surgery. After completing fellowship training in 2020, Dr. Zehnpfennig returned to Montana to bring this expertise to patients throughout the state.

Dr. Zehnpfennig has performed more than 1,000 robotic operations and specializes in robotic and laparoscopic colorectal surgery. He performs complex procedures for colon cancer, rectal cancer, diverticulitis, inflammatory bowel disease, colostomy reversal, and rectal prolapse.

He has particular expertise in natural-orifice specimen extraction, an advanced technique that allows the surgical specimen to be removed without a large abdominal extraction incision. This approach is associated with less postoperative pain, fewer wound-related complications, and faster recovery than conventional abdominal specimen extraction.¹

Dr. Zehnpfennig uses the Intuitive da Vinci robotic platform to perform transanal minimally invasive surgery (TAMIS) for selected rectal tumors and robotic ventral mesh rectopexy (VMR) for rectal prolapse. He also performs advanced procedures for complex anal fistulas, including endorectal advancement flap, ligation of the intersphincteric fistula tract, commonly called the LIFT procedure, and transanal opening of the intersphincteric space, or TROPIS.

For benign anorectal conditions, Dr. Zehnpfennig provides comprehensive treatment for hemorrhoids, anal fissures, anal skin tags, and other common but often undertreated disorders. Treatment options include office-based procedures, surgical hemorrhoid treatment, cosmetic removal of anal skin tags, and Botox injections for chronic anal fissures.

His practice incorporates enhanced recovery principles designed to reduce pain and help patients return home and resume normal activity sooner. These include minimally invasive surgical techniques, multimodal pain control, early feeding, early mobilization, and careful fluid management. Many patients undergoing colon resection meet discharge criteria on the first postoperative day, and selected patients may qualify for same-day discharge.

Patients receive direct, specialist-level care from diagnosis through recovery. To schedule a consultation, contact the office by phone or request an appointment online.

1. Cao L, et al. Evaluation of the efficacy of natural orifice specimen extraction surgery versus conventional laparoscopic surgery for colorectal cancers: a systematic review and meta-analysis. Colorectal Disease. 2025.