Efficacy of greater occipital nerve block for pain relief in patients with postdural puncture headache A meta-analysis

Background: This study aimed at assessing the therapeutic effectiveness of greater occipital nerve block (GONB) against postdural puncture headache (PDPH). Methods: Studies investigating analgesic effects of GONB against PDPH in adults were retrieved from the MEDLINE, EMBASE, Google scholar, and Cochrane central databases from their inception dates to May, 2021. Pain score at postprocedural 24 hours was the primary endpoint, while secondary endpoints were pain score at postprocedural 1 hour and 12 hours as well as the risk of intervention failure. Results: Of the 7 studies (randomized controlled trials [RCTs], n = 4; non-RCTs, n = 3) that recruited 275 patients, 2 investigated female patients undergoing cesarean section and the other 5 were conducted in both obstetric and nonobstetric settings. Pooled results showed a lower mean pain score at 24 hours (i.e., primary outcome) (mean difference [MD] = -2.66, 95%: CI: -3.98 to -1.33, P I-2 = 97%, 6 studies), 1 hour (MD = -4.23, 95% confidence interval [CI]: -5.08 to -3.37, P I-2 = 86%, 5 studies), and 6 hours (MD = -2.78, 95% CI: -4.99 to -0.57, P = .01; I-2 = 98%, 4 studies) in patients with GONB compared to those without. Trial sequential analysis supported the robustness of evidence at postprocedural 24 hours. The use of GONB also decreased the risk of intervention failure (relative ratio [RR] = 0.4, 95% CI: 0.19 to 0.82, P = .01; I-2 = 96%, 6 studies, 277 patients). Conclusion: Our results suggested a therapeutic effect of greater occipital nerve block against postdural puncture headache up to postprocedural 24 hours. Further large-scale studies are warranted to evaluate its therapeutic benefit beyond the acute stage.