Intravenous Acetaminophen (Paracetamol) for Post-Craniotomy Pain; Systematic Review and Meta-analysis of Randomized Clinical Trials

BACKGROUND: Acute pain control after supratentorial craniotomy is considered among the most important indicators of postoperative recovery. The aim of this study was to determine the effects of intravenous acetaminophen on postcraniotomy pain. METHODS: We searched databases including Embase, Scopus, Medline, Cochrane Library, and Web of Science until April 2019. Cochran Q test and I-2 statistic were used to assess the heterogeneity across included clinical trials. Standardized mean difference (SMD) and 95% confidence interval (CI) were used to estimate pooled effect sizes. RESULTS: Out of 479 reports, 5 randomized controlled trials met the inclusion criteria and were appropriate for our meta-analysis, which included a total of 2635 patients. The pooled results of included clinical trials indicated that paracetamol intake significantly decreased rescue dose (SMD, -0.67; 95% CI, -1.15 to - 0.19; P < 0.01; I-2 = 90.0%), total dosage of rescue (SMD, -0.78; 95% CI, -1.18 to - 0.37; P < 0.01; I-2 = 86.0%), intensive care unit length of stay (SMD, -0.24; 95% CI, -0.44 to -0.04; P = 0.01; I-2= 0.0%), and visual analog scale score (SMD, -0.16; 95% CI, -0.31 to -0.00; P = 0.04; I-2 = 71.7%) and increased patient satisfaction (SMD, 0.28; 95% CI, 0.14-0.43; P< 0.01; I-2 = 10.2%) among patients with craniotomy. Time to rescue (SMD, 0.21; 95% CI, -0.42 to 0.85; P = 0.51; I-2 = 94.3%) and hospital length of stay (SMD, -0.04; 95% CI, -0.24 to 0.16; P = 0.69; I-2 = 0.0%) did not significantly change after paracetamol intake. CONCLUSIONS: The results of this systematic review and meta-analysis indicate that preoperative intravenous administration of acetaminophen is associated with decreased postoperative pain, need for rescue analgesics, and dosages of analgesics after craniotomy surgery.