Pathophysiology of Acute Postoperative Pain

Timothy J. Brennan, MD, PhD

Professor of Anesthesiology
Department of Anesthesiology
University of Iowa College of Medicine
Iowa City, IA

Postoperative incisional pain is a unique and common form of acute pain. Despite evidence for reduced morbidity and improved outcomes with effective postoperative pain management, pain remains under-treated after surgery. Surveys suggest that most patients experience moderate to severe postoperative pain, often lasting for days after surgery. Deep tissue is highly sensitive to incisions and subsequent activation of the nociceptive system. A better understanding of the mechanisms underlying postoperative pain could lead to painless surgery. Experimental models of incisional pain in rodents have shown the presence of “ischemic-like” signaling in deep tissue: oxygen levels are low, whereas levels of lactate and nerve growth factor are elevated. Recent research has shown the importance of ischemia and lactic acid as pain generators and potential targets for therapy. Alternative approaches could desensitize C-fibers with compounds such as capsaicin, resulting in increased analgesia. Here, Dr. Brennan discusses the use of experimental models to develop novel postoperative pain therapies, with the long-term goal of decreasing the incidence of persistent pain following surgery.

References

Hamalainen MM, Subieta A, Arpey C, Brennan TJ. Differential effect of capsaicin treatment on pain-related behaviors after plantar incision. J Pain. 2009;10:637-45.
Pogatzki-Zahn EM, Zahn PK, Brennan TJ. Postoperative pain—clinical implications of basic research. Best Pract Res Clin Anaesthesiol. 2007;21(1):3-13.
Brennan TJ, Zahn PK, Pogatzki-Zahn EM. Mechanisms of incisional pain. Anesthesiol Clin North America. 2005;23:1-20.

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