Do Regional Nerve Blocks during Bimaxillary Surgery Decrease Postoperative Pain and Vomiting Compared with Patient- Controlled Analgesia?

Abstract

Postoperative pain after orthognathic surgery is commonly managed with opioids, which can cause nausea and vomiting. The purpose of this study was to determine whether regional nerve blocks during bimaxillary surgery reduced postoperative pain and vomiting compared with patient-controlled analgesia (PCA). This retrospective cohort study recruited patients who underwent bimaxillary surgery between August 2018 and September 2020 at the Fourth Military Medical University Hospital. Participants whose procedures involved the cheekbone, temporomandibular joint, mandibular angle, or an autogenous iliac bone graft and those who were admitted to the intensive care unit after surgery were excluded. The primary predictor variables were postoperative analgesia management, regional maxillary and inferior alveolar nerve blocks, and PCA. The primary outcome variables were moderate-to-severe postoperative pain and postoperative vomiting (POV) during the first 24hours. Moderate-to-severe pain was defined as pain numerical rating scale ≥4, POV was defined as vomiting of gastrointestinal contents. The study covariates included demographic, surgical, and anesthesia characteristics. Statistical analyses were conducted using an unpaired t-test, χ2 test, or Fisher's exact test for the bivariate analysis. A multivariate logistic regression analysis was performed to assess the associations between the primary predictor variables and outcomes. Statistical significance was set at P<.05. 354 participants were included in the study (262 in the nerve block group, mean age 22.5±4.0years; 92 in the PCA group, mean age 22.6±4.4years; P=.81). There was no significant difference in sex between the groups (63.4 and 55.4% females in nerve block and PCA groups, respectively, P=.18). The multivariate regression analyses demonstrated that nerve blocks did not decrease moderate-to-severe postoperative pain (7.6 vs 10.9%, adjusted odds ratio=0.67, 95% confidence interval: 0.22-2.01, P=.48), although they were associated with decreased POV (38.5 vs 65.2%, adjusted odds ratio=0.34, 95% confidence interval: 0.18-0.65, P=.001). For bimaxillary surgery, regional nerve blocks as opioid-free postoperative analgesia were not significantly associated with decreased postoperative pain but were associated with a low POV risk.