Scalp block for analgesia after craniotomy: A meta-analysis

Background and Aims: A previous meta-analysis reported that scalp block had limited benefits (low-quality evidence) compared to no-scalp block modalities for analgesia after craniotomy. However, it included studies using two different pain intensity measurement scales. Therefore, we performed another meta-analysis using a single scale. Methods: We conducted the search for all randomised controlled trials evaluating the effect of scalp block on postcraniotomy pain compared to no-scalp block in Cochrane Central Register of Controlled Trials and PubMed database. We assessed the quality of included studies employing GRADE approach. We performed random-effects inverse-variance weighted meta-analysis of outcomes including pain intensity assessed by a 0--10 visual analog scale and opioid consumption during the first 24 h postoperative period using RevMan 5.3. Results: A total of 10 studies (551 patients) were included. It revealed a statistically significant mean pain intensity reduction in scalp block group when compared to no-scalp block at very early and early 24 h period (seven trials, very low-quality evidence, mean difference (MD) = -1.37, 95% confidence interval (CI): -2.23 to -0.05, l(2) = 70%; nine trials, very low-quality evidence, MD = -1.16, 95% CI: -2.09 to -0.24, l(2) = 57%, respectively). There was also reduction in the opioid requirements over the first 24 h postoperatively. Conclusion: Scalp block might be useful at <6 h postcraniotomy with very-low quality evidence. Additionally, it had uncertain but moderate effect on reducing total 24 h opioid consumption. Therefore, more studies are needed to reach optimal information size.