EP462 - Analysis of Perioperative Intrathecal Morphine in Colorectal Surgery

Sunday, May 10, 2026

1:46 PM - 1:51 PM ET

ePoster Presenter(s)

Peyton M. Murdock, MD (she/her/hers)

General Surgery Resident
University of Tennessee Medical Center Knoxville
University of Tennessee Medical Center Knoxville
Knoxville, TN, United States

Disclosure information not submitted.

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Author(s)

Bailey Humphreys, MD

Resident
University of TN graduate school of medicine
University of Tennessee Graduate School of Medicine Knoxville
Alcoa, TN, United States

Disclosure information not submitted.
CP

Canaan Pratt, Medical Student

Medical Student
UTHSC COM - - Memphis, TN
Memphis, Tennessee, United States

Disclosure information not submitted.
FW

Faith K. Wilson, BA

Medical Student
University of Tennessee Health Science Center College of Medicine Knoxville
Knoxville, Tennessee, United States

Disclosure information not submitted.
AN

Amirreza Nikbakht, M.Ed.

Graduate Research Assistant
Office of Biostatistics and Research Consultation (OBRC), University of Tennessee Graduate School of Medicine
Knoxville, Tennessee, United States

Disclosure information not submitted.
AR

Andrew J. Russ, MD FACS FASCRS, MD

Professor Program Director, General Surgery Residency Chief, Division of Colorectal Surgery
University of Tennessee Graduate School of Medicine
Knoxville, Tennessee, United States

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RH

Robert E. Heidel, PhD, PStat

Professor of Biostatistics
UTHSC College of Medicine, Knoxville
Knoxville, Tennessee, United States

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Senior Author(s)

GL

Gregory Low, MD

Assistant Professor
University of Tennessee Graduate School of Medicine
Knoxville, Tennessee, United States

Disclosure information not submitted.

Author(s)

MC

Mark A. Casillas, Jr., MD, FACS, FASCRS

Assistant Professor
UT Graduate School of Medicine
Knoxville, Tennessee, United States

Disclosure information not submitted.

Purpose/Background: Multimodal pain control has been a cornerstone of colorectal enhanced recovery after surgery to optimize patient outcomes, particularly through decreasing overall morphine milligram equivalents (MMEs). Intrathecal morphine (ITM) has been used as an alternative to epidural analgesia in patients undergoing major abdominal surgery. Despite the emerging literature showing some reduction of MMEs with the use of regional anesthetic techniques, there continues to be a need for evidence regarding the use of ITM in colorectal surgery. We aim to examine the impact of ITM on MMEs in colorectal surgery.

Methods/Interventions: We conducted a retrospective review of colorectal patients from 2019-2025 at a single academic institution. All patients undergoing major abdominal colorectal surgery at our center were included. Exclusion criteria included age less than 18, incomplete data availability, pregnant patients, or being in a vulnerable population.

Results/Outcomes: Patients were grouped into those who underwent perioperative ITM compared to those who did not with the main endpoints being MME 24h and 48h post-op. For patients who received perioperative ITM, MME 24h did not differ significantly (M = 69.34, SD = 31.94) compared to those who did not receive ITM (M = 84.83, SD = 37.81; p = 0.22). However, MME 48h was significantly higher among patients without ITM (M = 129.47, SD = 53.71) compared to those with ITM (M = 83.37, SD = 48.66; p = 0.02). We additionally analyzed surgical approaches, time to bowel function, and length of stay (LOS). There was not a significant difference in MME 24h among patients who underwent minimally invasive (MIS) versus open surgery (p = 0.09) but there was a difference in MME 48h with patients undergoing open procedures (M = 81.35, SD = 38.32) requiring significantly higher MME compared to MIS (M = 81.35, SD = 38.32, p = 0.02). There was not a significant difference in time to bowel function (p = 0.91, p = 0.38) or LOS (p = 0.91, p = 0.12) regarding MME 24h and 48h.

Conclusion/Discussion: Pain control continues to be an area of exploration in colorectal enhanced recovery after surgery and ITM is an accessible, low-risk procedure to improve patient pain control in the early post-operative period. This study demonstrated that ITM is correlated with decreased MME 48h from surgery in patients undergoing major abdominal colorectal surgery which suggests that the effects of ITM extend beyond the expected clinical duration of action of 24 hours. MMEs were increased in patients undergoing open surgery compared to MIS. There was not, however, a significant difference in time to bowel function or LOS. We plan to additionally analyze the use of transversus abdominis plane (TAP) blocks in this population to compare these perioperative pain control procedures to add further depth to this study.