Intraoperative blood loss and surgical time according to the direction of maxillary movement.

BACKGROUND Excessive bleeding is one of the most severe complications of orthognathic surgery (OGS). This study investigated the associations of intraoperative blood loss and surgical time with the direction of maxillary movement. METHODS This retrospective study involved patients who underwent OGS from October 2017 to February 2020. They were classified based on whether maxillary setback was performed into groups A1 and B1, respectively. Relative blood loss (RBL, %) was used as an indicator to compare intraoperative blood loss between the two groups. The surgical time of the two groups was also measured. Subsequently, the patients were reclassified based on whether posterior impaction of the maxilla was performed into groups A2 and B2, respectively. RBL and surgical time were measured in the two groups. Simple linear and multiple regression analyses were performed. P-values <0.05 were considered to indicate statistical significance. RESULTS Eighteen patients were included. The RBL and surgical time for the groups were: A1, 13.15%±5.99% and 194.37±42.04 minutes; B1, 12.41%±1.89% and 196.50±46.07 minutes; A2, 13.94%±3.82% and 201.00±39.70 minutes; and B2, 9.61%±3.27% and 188.84±38.63 minutes, respectively. Only RBL showed a statistically significant difference between the two groups (A2 and B2, P=0.04). CONCLUSIONS Unlike maxillary setback, posterior impaction of the maxilla showed a significant association with RBL during surgery. When performing posterior impaction of the maxilla, clinicians need to pay particular attention to surgery and postoperative care.