Assessment of blood loss and need for transfusion during bimaxillary surgery with or without maxillary setback

The objective of this study was to compare the blood loss, transfusion needs, and operation times in subjects who underwent bimaxillary surgery with versus without maxillary setback.

A retrospective chart review was completed in all patients who underwent bimaxillary surgery from March 2009 to August 2010. The inclusion criterion was the availability of a complete chart record. Patients were divided into 1 of 2 groups based on maxillary setback procedure. The predictive variable was the treatment group. The primary outcome variable was blood loss as measured by the change in hemoglobin. The secondary outcome variables were operation time and transfusion need. The other study variables were a patient's characteristics (ie, age and gender). Mann-Whitney test was performed to compare unpaired samples. Student t test was performed to compare operation time. Multiple regression analysis was used to analyze the adjusted relation among the study variables.

There were 82 patients (17 male and 65 female; mean age, 28.0 ± 4.9 yr; age range, 18 to 35 yr) who underwent bimaxillary surgery in this study. The mean hemoglobin decreases were 1.72 g/dL (standard deviation, 0.67 g/dL) in the nonsetback group and 2.37 g/dL (standard deviation, 0.76 g/dL) in the setback group. The average operation times were 158.24 ± 30.36 minutes (range, 127.88 to 188.6 min) in the nonsetback group and 194.35 ± 29.20 minutes (range, 165.15 to 223.55 min) in the setback group. Transfusion was not performed in any patient. After adjusting for potential factors, the multiple regression model showed that the treatment group was associated with blood loss (P < .0001) and operation time (P < .0001).

This study shows that intraoperative bleeding and operation time increased significantly in patients undergoing mandibular ramus osteotomy and Le Fort I osteotomy with maxillary setback. However, transfusion generally is not required during 2-jaw surgery, regardless of maxillary setback.