The Department of Surgery

Mark A. Casillas, Jr., MD, FACS

Associate Professor
Division of Colorectal Surgery

Clinical Focus

Colon and Rectal Surgery; Neoplasms of the Colon, Rectum, and Anus; Inflammatory Bowel Disease; Benign Diseases of the Anorectum; Minimally Invasive Surgery; Robotic Colon and Rectal Surgery; Single Incision Laparoscopy; Transanal Endoscopic Microsurgery

Research Focus

Advances in Minimally Invasive Surgery
Advances in Robotic Colorectal Surgical Outcomes

Education

Graduate School
University of Alabama at Birmingham, Birmingham, AL

Medical School
University of Alabama School of Medicine, Birmingham, AL

Internship
General Surgery, Brown University Medical School, Providence, RI

Residency
General Surgery, St. Joseph Mercy Hospital, Ann Arbor, MI

Fellowship
Colon and Rectal Surgery, Indiana University School of Medicine, Indianapolis, IN

Certifications

American Board of Surgery
American Board of Colon and Rectal Surgery

Professional Affiliations

American Society of Colon and Rectal Surgeons, Fellow
American College of Surgeons, Fellow
Society of American Gastrointestinal and Endoscopic Surgeons

Current Publications

Schmocker RK, Enomoto LM, Low GK, McLoughlin JM, Casillas MA Jr, Antill AC, Heidel RE, Russ AJ.
Further distance from treating facility is associated with advanced colon cancer at presentation and increased mortality. Am Surg. 2024 Mar 29:31348241241613. doi: 10.1177/00031348241241613. Online ahead of print.

Current Presentations

Humphreys B, Low GK, Russ AJ, Murdock PM, Nikbakht A, Heidel RE, Pratt C, Brooks EC, Casillas MA Jr. Outcomes of a nurse navigator program in rectal cancer management: A retrospective review. Presented at American Society of Colon and Rectal Surgeons; May 9, 2026; Tampa Bay, FL.

Ramos-Mas O, Casillas MA Jr. Postoperative chylous ascites following low anterior resection: A case report. Presented at American Society of Colon and Rectal Surgery Annual Scientific Meeting 2026; May 9, 2026; Tampa, FL.

Murdock PM, Humphreys B, Pratt C, Wilson FK, Nikbakht A, Russ AJ, Heidel RE, Casillas MA Jr, Low GK. Analysis of perioperative intrathecal morphine in colorectal surgery. Presented at 2026 American Society of Colon and Rectal Surgeons Annual Scientific Meeting; May 9, 2026; Tampa, FL.

Mazonas TW, Russ AR, Low GK, Casillas MA. Fin tox. Presented at 2024 Annual Scientific Meeting ; 2024 June - 1; Baltimore, MD.

Russ AR, Low GK, Casillas MA. Fin tox. Presented at 2024 ASCRS Annual Scientific Meeting ; 2024 May - 1; Baltimore, MD.

Murdock P, Jong J, Russ A, Casillas M. Robotic versus laparoscopic low anterior resection for rectosigmoid adenocarcinoma Presented at Tennessee Chapter of American College of Surgeons ; 2023 July-27; Fall Creek Falls, TN.

Murdock P, Jong J, Heidel E, Casillas M, Russ A. Robotic versus Laparoscopic Low Anterior Resection for Rectosigmoid Adenocarcinoma: A Single Center Experience Presented at 2023 Annual Meeting of the Tennessee Chapter, American College of Surgeons; 2023 June - 27; Spencer,Tennessee.