The effect of intrathecal morphine on postoperative Natural Killer Cell activity in patients undergoing abdominal surgery for pancreatobiliary malignancy:A randomized control trail.

Pain is a complex and subjective experience that involves both sensory and emotional components. It is characterized as an unpleasant sensation associated with actual or potential tissue damage. Acute pain refers to pain that lasts for a short duration, typically not exceeding three months. During the perioperative period, acute pain can occur due to the trauma of surgery, inflammation, and overactivity of the sympathetic nervous system. If not effectively managed, acute pain can progress to chronic persistent post-surgical pain.

Studies on animals consistently suggest that poorly controlled pain after surgery can lead to immunosuppression and potentially enhance the development of malignant processes. The most significant effect of this immunosuppression is a decrease in the count and activity of Natural Killer (NK) cells. Additionally, morphine, commonly used for pain management, has been found to have immunosuppressive effects. This may pose a risk for patients who have undergone surgery, as a suppressed immune system can make them more vulnerable to postoperative infections and hinder defense against malignant tumors.

Uncontrolled acute perioperative pain can also amplify the surgical stress response. The enhanced activity in the sympathetic nervous system and neuroendocrine responses can further decrease Natural Killer cell activity, potentially increasing the risk of cancer recurrence and metastasis. Natural Killer cells play a crucial role in recognizing and eliminating tumor cells without relying on specific antigens, making them a primary defense mechanism against tumor development and metastases.

To evaluate the effects of intrathecal morphine on immune processes in surgery, we are conducting investigations on Natural Killer cell activity using immunological tests. Additionally, pain control without excessive opioid consumption is a challenge for physicians. Intrathecal morphine (ITM) has emerged as a promising alternative that can improve patient outcomes. This is particularly relevant for postoperative analgesia following pancreatobiliary cancer surgery, which often poses challenges due to insufficient pain management.

Intrathecal anaesthesia offers a simpler and quicker alternative to epidural anaesthesia, with a lower rate of technical failure. Similar to epidural analgesia, intrathecal morphine has demonstrated efficacy in improving postoperative pain scores and reducing the need for rescue analgesia after major abdominal cancer surgery. This is important considering the significant postoperative pain experienced by patients undergoing definitive surgery for pancreatobiliary malignancies.

While intravenous patient-controlled analgesia (IV PCA) and continuous epidural analgesia have been considered standard analgesic modalities for abdominal surgery in patients with malignancies, their use can be controversial.

Our study will compare, effect of addition of intrathecal morphine on post operative pain regime of pancreato-biliary malignancy, on quantity of Natural killer cells. We will also compare the cumulative 24-hour IV opioid consumption during the postoperative period between patients who received ITM and those who underwent sham procedures. In addition to pain severity, we will examine variables relating to postoperative recovery profiles, complications, duration of hospital stay, and the impact on serum C-reactive protein (CRP) levels as secondary outcomes. These findings will contribute to our understanding of the immune and pain management processes in perioperative care for patients with pancreatic and biliary malignancies.