The Effect of Scalp Nerve Block on Postoperative Analgesia and Stress Response in Patients Undergoing Craniotomy: A Meta-Analysis.

Objective: To evaluate the effect of scalp nerve block (SNB) on postoperative analgesia and stress response in patients undergoing craniotomy by meta-analysis.

Methods: PubMed, Embase, Cochrane Library, CNKI, and Wanfang databases were searched for randomized controlled trials involving SNB for elective craniotomy under general anesthesia from inception to August 1, 2022. Meta-analysis was performed using RevMan 5.4 and Stata MP17.0. Based on scalp block operation time (preoperative block, postoperative block), different control groups (no block, normal saline), local anesthetic types (bupivacaine, levobupivacaine, ropivacaine), the postoperative pain score at different time points was analyzed by subgroup analysis.

Results: 23 studies involving 1515 patients were included. The combined results showed that SNB could significantly reduce the pain scores at all time points compared with the control group (P < .05). Subgroup analysis showed that the analgesic effect of preoperative scalp nerve block was better than that of postoperative block, and the effect of ropivacaine and levobupivacaine was better than bupivacaine. SNB could reduce morphine consumption within 48 hours after surgery (SMD = -1.51, 95% CI -2.80 -0.21, P = .02, I2 = 89%). The first rescue analgesia time was significantly longer in the SNB group than the control group (SMD = 0.57, 95% CI 0.16-0.99, P = .01, I2 = 68.76%). Compared with the control group, the levels of postoperative angiotensin, intraoperative blood glucose, and both intraoperative and postoperative cortisol levels were significantly decreased (P < .05). SNB can inhibit hemodynamic changes caused by surgical stimulation and effectively reduce the incidence of postoperative nausea and vomiting (RR = 0.71, 95% CI 0.51~0.97, P = .03).

Conclusion: Scalp nerve block is an effective analgesic that reduces pain within 48 hours after craniotomy. It effectively inhibit the stress response caused by surgical stimulation, stabilize hemodynamics, and reduce the incidence of postoperative nausea and vomiting.