Background and Aims Two-jaw plastic surgery is associated with severe perioperative pain due to osteotomy. The efficacy of ultrasound-guided maxillary nerve block (MaxNB) and inferior alveolar nerve block (InfNB) has been reported. However, no study evaluates the efficacy of simultaneous blocks (Max/InfNB).

Methods This study was approved by the ethics committees of two institutions (322-271, 2104). Forty-two patients aged 16 years or older undergoing two- jaw plastic surgery under general anaesthesia were randomly allocated to block group: ultrasound-guided bilateral Max/InfNB were performed under general anaesthesia, or to control group: general anaesthesia alone. The block group received 5 mL of 0.375% levobupivacaine per site for 20 mL. The primary outcome was the rescue analgesics number used up to 24 hours after the block. In addition, intraoperative opioid consumption was recorded. In the block group, arterial levobupivacaine blood levels were measured five times up to 60 minutes after the block by Liquid Chromatograph-tandem Mass Spectrometer.

Results Eighteen and 22 patients completed the study in block and control group, respectively. The median[IQR] rescue analgesics numbers were not significantly different (block: 0[0-1.25] vs. control: 0[0-1.0], p=0.79). However, the mean(SD) intraoperative fentanyl/remifentanil consumption was significantly lower in the block group (fentanyl: 561(218) vs. 791(250) μg, p=0.004, remifentanil: 3.75(1.20) vs. 5.46(1.54) mg, p<0.001). The maximum mean(SD) levobupivacaine blood level was 1.46(0.40) μg/mL 5 minutes after the block.

Conclusions Max/InfNB for two-jaw plastic surgery decreased intraoperative opioid consumption compared to general anaesthesia alone, but did not provide effective postoperative analgesia. The arterial levobupivacaine levels after the block remained in the safe range.