Association of scalp block with intraoperative hemodynamic profiles and postoperative pain outcomes at 24-48 hours following craniotomy: An updated systematic review and meta-analysis of randomized controlled studies

Background: Despite the demonstrated analgesic efficacy of scalp block (SB) during the immediate postoperative period, the impact of SB on pain outcomes at postoperative 24 and 48 h in adults receiving craniotomy remains unclear.

Methods: The databases of Medline, Embase, and Cochrane Central Register were searched from inception to January 2022 for available randomized controlled trials (RCTs). The primary outcome was the severity of pain at postoperative 24 and 48 h, while the secondary outcomes included morphine consumption, hemodynamic profiles after surgical incision and in the postanesthesia care unit (PACU), and risk of postoperative nausea/vomiting (PONV).

Results: Meta-analysis of 12 studies revealed a lower pain score [MD = -0.83, p = 0.03, 375 patients, certainty of evidence (COE): low] and morphine consumption (MD = -9.21 mg, p = 0.03, 246 patients, COE: low) at postoperative 24 h, while there were no differences in these pain outcomes at postoperative 48 h (COE: low). The use of SB significantly decreased intraoperative heart rate (MD = -10.9 beats/min, p < 0.0001, 189 patients, COE: moderate) and mean blood pressure (MD = -13.02 mmHg, p < 0.00001, 189 patients, COE: moderate) after surgical incision, but these hemodynamic profiles were comparable in both groups in the PACU setting. There was also no difference in the risk of PONV between the two groups (RR = 0.78, p = 0.2, 299 patients, COE: high).

Conclusion: This meta-analysis demonstrated that scalp block not only provided hemodynamic stability immediately after surgical incision but was also associated with a lower pain score and morphine consumption at postoperative 24 h. Further studies are needed for elucidation of its findings.