Our Team


Jon Vogel, MD, MACS, FASCRS

Jon Vogel, MD, FACS, FASCRS

Professor of Surgery
Section Head, Colorectal Program

Office Phone: 303-724-2728

E-mail: jon.vogel@cuanschutz.edu

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Elise Birnbaum, MD

Elisa Birnbaum, MD, FACS, FASCRS

Professor of Surgery

Office Phone: 303-724-2728

E-mail: elisa.birnbaum@cuanschutz.edu

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Steve Ahrendt, MD, FACS

Steven A. Ahrendt, MD, FACS

Professor of Surgery

(Dr. Ahrendt's colorectal surgery practice is limited to colorectal and anal cancer.)

Ana Gleisner, MD, PhD

Ana Gleisner, MD, PhD

Assistant Professor of Surgery

(Dr. Gleisner's colorectal surgery practice is limited to colorectal and anal cancer.)

Martin McCarter, MD

Martin McCarter, MD, FACS

Professor of Surgery

(Dr. McCarter's colorectal surgery practice is limited to colorectal and anal cancer.)

Whitney Herter, PA-C

Whitney K. Herter, PA-C

Physician Assistant
Colorectal Cancer Multidisciplinary Clinic Coordinator

Phone: 720-848-0714

E-mail: whitney.herter@cuanschutz.edu

Shanna Zwick, PA-C

Shanna Zwick, PA-C

Physician Assistant

Phone: 720-724-2728

E-mail: shanna.zwick@cuanschutz.edu

Trish Knox

Trish Knox

Patient Affairs Coordinator / Scheduling

Phone: 303-724-2727

E-mail: patricia.knox@cuanschutz.edu

Tanya Obernyer

Tanya Obernyer

Patient Affairs Coordinator / Scheduling

Phone: 303-724-2726

E-mail: tanya.obernyer@cuanschutz.edu