The effectiveness of scalp nerve block on hemodynamic response in craniotomy: a systematic review and meta-analysis of randomized trials

INTRODUCTION: Strategies that blunt noxious stimuli and stabilize hemodynamics may reduce perioperative cardiovascular complications and enhance recovery after craniotomy. EVIDENCE ACQUISITION: Our systematic literature review and meta-analysis investigated whether scalp nerve block (SNB) reduces the acute hemodynamic response compared with non-SNB (scalp infiltration or control) in adult patients undergoing elective craniotomy. We searched MEDLINE, EMBASE, CENTRAL, and two Chinese databases for randomized trials. Primary outcomes included mean arterial pressure and heart rate during skull pin insertion and surgical incision in craniotomy. Secondary outcomes included incidence of hypertension and dosage of intraoperative analgesic opioids used. Random-effects models were used for meta-analyses. EVIDENCE SYNTHESIS: SNB significantly reduced the mean arterial pressure (mean difference: -14.00 mmHg; 95% confidence interval [CI]: -19.71 to -8.28) and heart rate (mean difference: -11.55 beat/min; 95% CI: -19.31 to -3.80), when compared with non-SNB during skull pin insertion. A similar trend was observed during skin incisions (SNB vs. non-SNB, mean difference in mean arterial pressure: -9.46 mmHg; 95% CI: -14.53 to -4.38; mean difference in heart rate: -9.34 beat/min; 95% CI: -15.40 to -3.28). Subgroup analysis showed that, compared with scalp infiltration, SNB reduced mean arterial pressure and heart during pin insertion but not during skin incisions. SNB also reduced the incidence of intraoperative hypertension, but no difference was observed in intraoperative opioid consumption when compared with non-SNB. CONCLUSIONS: SNB alleviated the craniotomy-associated hemodynamic response. SNB may be superior to scalp infiltration in maintaining hemodynamic stability during pin insertion. However, high-quality trials are still needed to provide more conclusive evidence.