RESUMEN
Background@#Excessive bleeding is a major intraoperative risk associated with orthognathic surgery. This study aimed to investigate the factors involved in massive bleeding during orthognathic surgeries so that safe surgeries can be performed. Patients (n=213) diagnosed with jaw deformities and treated with bimaxillary orthognathic surgery (Le Fort I osteotomy and bilateral sagittal split ramus osteotomy) in the Department of Oral and Maxillofacial Surgery at the Suidobashi Hospital, Tokyo Dental College between January 2014 and December 2016 were included. Using the patients’ medical and operative records, the number of cases according to sex, age at the time of surgery, body mass index (BMI), circulating blood volume, diagnosis of maxillary deformity, direction of maxillary movement, operative duration, incidence of bad split, injury of nasal mucosa, and blood type were analyzed. @*Results@#The results revealed that BMI, circulating blood volume, nasal mucosal injury, and operative time were associated with the risk of intraoperative massive bleeding in orthognathic surgeries. Chi-square tests and binomial logistic regression analyses showed significant differences in BMI, circulating blood volume, direction of maxillary movement, operative duration, and injury to the nasal mucosa. Operative duration emerged as the most important risk factor. Furthermore, a >4-mm upward migration of the posterior nasal spine predicted the risk of massive bleeding in orthognathic surgery. @*Conclusions@#The upward movement of the maxilla should be recognized during the preoperative planning stage as a risk factor for intraoperative bleeding, and avoiding damage to the nasal mucosa should be considered a requirement for surgeons to prevent massive bleeding during surgery.
RESUMEN
Major bleeding associated with sagittal split ramus osteotomy (SSRO) involves vessels such as the inferior alveolar, facial, and maxillary arteries and veins, and the retromandibular vein (RMV). The present study aimed to clarify and classify the three-dimensional variations in RMV position and course direction in relation to the mandible. Specimens comprised a total of 15 scientific cadavers, and the relationship between RMV and the mandible lateral and posterior views was observed.We identified 3 patterns on the lateral view, the mean distance between the RMV and the posterior border of the ramus was 3.9 mm at the height of the lingula. A total of five course patterns were identified on the posterior view. In no course pattern, the RMV inferior to the lingula was lateral to its position superior to the lingual. The present findings suggest that it may be possible to predict correlations with intraoperative bleeding risk. Further study is planned using contrast computed tomography in patients with jaw deformity for skeletal classification.
RESUMEN
Major bleeding associated with sagittal split ramus osteotomy (SSRO) involves vessels such as the inferior alveolar, facial, and maxillary arteries and veins, and the retromandibular vein (RMV). The present study aimed to clarify and classify the three-dimensional variations in RMV position and course direction in relation to the mandible. Specimens comprised a total of 15 scientific cadavers, and the relationship between RMV and the mandible lateral and posterior views was observed.We identified 3 patterns on the lateral view, the mean distance between the RMV and the posterior border of the ramus was 3.9 mm at the height of the lingula. A total of five course patterns were identified on the posterior view. In no course pattern, the RMV inferior to the lingula was lateral to its position superior to the lingual. The present findings suggest that it may be possible to predict correlations with intraoperative bleeding risk. Further study is planned using contrast computed tomography in patients with jaw deformity for skeletal classification.
RESUMEN
BACKGROUND: Along with the advances in technology of three-dimensional (3D) printer, it became a possible to make more precise patient-specific 3D model in the various fields including oral and maxillofacial surgery. When creating 3D models of the mandible and maxilla, it is easier to make a single unit with a fused temporomandibular joint, though this results in poor operability of the model. However, while models created with a separate mandible and maxilla have operability, it can be difficult to fully restore the position of the condylar after simulation. The purpose of this study is to introduce and asses the novel condylar repositioning method in 3D model preoperational simulation. METHODS: Our novel condylar repositioning method is simple to apply two irregularities in 3D models. Three oral surgeons measured and evaluated one linear distance and two angles in 3D models. RESULTS: This study included two patients who underwent sagittal split ramus osteotomy (SSRO) and two benign tumor patients who underwent segmental mandibulectomy and immediate reconstruction. For each SSRO case, the mandibular condyles were designed to be convex and the glenoid cavities were designed to be concave. For the benign tumor cases, the margins on the resection side, including the joint portions, were designed to be convex, and the resection margin was designed to be concave. The distance from the mandibular ramus to the tip of the maxillary canine, the angle created by joining the inferior edge of the orbit to the tip of the maxillary canine and the ramus, the angle created by the lines from the base of the mentum to the endpoint of the condyle, and the angle between the most lateral point of the condyle and the most medial point of the condyle were measured before and after simulations. Near-complete matches were observed for all items measured before and after model simulations of surgery in all jaw deformity and reconstruction cases. CONCLUSIONS: We demonstrated that 3D models manufactured using our method can be applied to simulations and fully restore the position of the condyle without the need for special devices.