EFFECT OF SCALP NERVE BLOCK ON FENTANYL CONSUMPTION AND LEVELS OF TNF-α, CORTISOL, AND BLOOD GLUCOSE IN ELECTIVE CRANIOTOMY

Abstract

Background: Craniotomy is commonly performed worldwide. As a response to surgery, the body develops surgical stress response mediated by pain and inflammatory mediators as an adaptive and protective mechanism against tissue injury. Craniotomy is a major surgery that may cause intense surgical stress response. Intense and persistent surgical stress response will become pathological process that increase perioperative complications. Surgical stress response can be in the form of metabolic or immune stress response. Metabolic stress response increases cortisol and blood glucose concentration, while immune stress response elevates proinflammatory cytokines, including TNF-α. Ropivacaine used in scalp nerve block is expected to reduce pain and inflammatory mediator production.

 Method: A prospective analytical experimental study was conducted on elective craniotomy patients at Dr. Soetomo Surabaya Hospital from October to November 2023. A total of 40 subjects were enrolled, divided into two groups, scalp nerve block (SNB) and non-scalp nerve block (non-SNB) group. The SNB group received scalp nerve block with 0.5% ropivacaine after induction of general anesthesia. Evaluation of pain relief was measured by fentanyl consumption during and 24 hours after surgery. TNF-α, cortisol, and blood glucose concentration were analyzed after induction, 6 hours after incision, and 24 hours after surgery as assessment of inflammatory response.

 Results: Total fentanyl consumption during surgery in SNB group was significantly lower compared to non-SNB group (1.72±0.23 vs 5.98±0.79 mcg/kg; p<0.001). 24 hours after surgery, total fentanyl consumption in SNB group was also significantly lower [0,00 (0,00-0,93) vs 0,785 (0,00-1,47) mcg/kg; p=0.002]. Average time from scalp nerve block to incision was 30-60 minutes. TNF-α concentration in SNB group was significantly lower at 6 hours after incision compared to non-SNB group (40,27±3,69 vs 93,59±4,23 pg/mL; p=0.000), and was not significantly different at 24 hours after surgery (94.00±4.35 vs 95.74±3.91; p=0.191). The increase of cortisol 6 hours after incision was significantly lower in SNB group (0.88±2.39 vs 4.99±2.47; p<0.001).  At 24 hours after surgery, cortisol concentration was also significantly lower in SNB group (9.60 ± 4.22 vs 12.18 ± 3.41; p=0.04). There was no significant difference in blood glucose concentration between both groups at 6 hours after incision and 24 hours after surgery (p=0.440 and p=0.498, respectively).

 Conclusion: Scalp nerve block with ropivacaine effectively suppress elevation of TNF-α concentration for 6.5 to 7 hours after administration, but is not effective until 24 hours after surgery. Fentanyl consumption and elevation of cortisol concentration can be suppressed until 24 hours after surgery.