Better late than never? Impact of local analgesia timing on postoperative pain in laparoscopic surgery: a systematic review and metaanalysis

This study aimed to determine the effect of local anesthesia administered before laparoscopic surgery (preemptive anesthesia) on postoperative pain. The authors searched Medline, EMBase, and the Cochrane Central Register of Controlled Trials, as well as reference lists of textbooks and relevant articles. They contacted experts in the field of anesthesia and laparoscopic surgery for randomized controlled trials comparing preemptive administration of local anesthesia at the incision site or intraperitoneally with postoperative anesthesia administration or placebo. Trials were systematically assessed for eligibility and validity, and data were extracted in duplicate. The data were pooled across studies using a random effects model. The 26 studies that met the inclusion criteria were included in the analysis. Preemptive incisional local anesthetic was superior to placebo in terms of visual analog pain scores (VAS) at 4 h (weighted mean difference [WMD], -9.49 mm; 95% confidence interval [CI], -15.50 to -3.48) and 24 h (WMD, -4.75 mm; 95%CI, -8.90 to 0.60). However, no difference was found between these measures and those for postoperative incision-site infiltration. Preemptive intraperitoneal local anesthetic was superior to placebo in terms of VAS at 4 h (WMD, 5.76 mm; 95%CI, -11.27 to -0.25), 8 h (WMD, -9.64 mm; 95%CI, -13.68 to -5.60), 12 h (WMD, -4.68 mm; 95%CI, -5.86 to -3.49), and 24 h (WMD, -5.57 mm; 95%CI, -8.35 to -2.79), and superior to postoperative anesthesia administration at 8 h (WMD, -7.42; 95%CI, -13.40 to -1.45), 12 h (WMD, -7.27 mm; 95%CI, -10.26 to -4.28), and 24 h (WMD, -7.95 mm; 95%CI, -12.33 to -3.56). Preemptive administration of local anesthetic at the incision site reduces postoperative pain compared with placebo but achieves an analgesic effect similar to that of postincisional anesthetic infiltration. Preemptive local anesthetic administered intraperitoneally decreases postoperative pain compared with both placebo and postoperative infiltration. Surgeons should use local analgesia in laparoscopic surgery to decrease postoperative pain, but the timing of administration is significant only for intraperitoneal infiltration.