Effect of Bilateral Ultrasound-Guided Intermediate Cervical Plexus Block Combined With General Anesthesia on THE Stress Response in Patients Undergoing Anterior Cervical Spine Surgery. A Randomized Controlled Study

Stress response is the name given to the hormonal and metabolic changes which follow injury or trauma. It may lead to changes in the nervous, endocrine and immune systems, and alterations in metabolic processes and functions. The stress response can shift from an adaptive and protective role to a pathogenic occurrence, especially when it is strong and chronic.

Stress hormones, the most prevalent of which is cortisol, have a circadian pattern in which they gradually climb after night sleep to reach a peak at early morning wake-up time, then gradually decline as the day progresses .

This pattern, however, can be disrupted by any stressful situation, such as severe pain from surgery, which has been linked to a progressive rise in cortisol levels both intraoperatively and in the early postoperative period.

Cytokines are group of low molecular weight proteins that modulate the systemic inflammatory response elicited by surgical intervention. Increased levels of proinflammatory cytokines, including interleukin-6 (IL-6) which is the main cytokine responsible for inducing the systemic changes, is an early features of acute injury. Interleukin-6 could be a good marker for research purposes that reflects and compares postoperative stress levels.

Spine surgeries are increasingly being performed as short-stay surgical procedures, and anterior cervical decompression and fusion is one such procedure .Postoperative incisional pain has been described as moderate in intensity, requiring opioid analgesics in most cases. Nonetheless, opioid-related side effects such as nausea, vomiting, and respiratory depression are undesirable in these patients who are at risk for airway problems due to surgical retraction or wound hematoma.