Regarding diagnostic imaging for surgical correction of jaw deformities, a three-dimensional evaluation of upper-airway structures composing the airway wall morphology is considered to be essential for predicting post-operational changes in the volume and shape of the airway. The aims of this study were as follows: (1) to propose useful measuring methods for estimating the morphology of the pharyngeal airway, (2) to identify which morphologic factor has the greatest influence on the volume of the pharyngeal airway, and (3) to investigate the relationship between the maxillofacial morphology and pharyngeal airway shape.
Pre-operative CT images of seventy-nine patients with jaw deformity aged from 15 to 20 years who were candidates for surgical orthodontic treatment were used in this study. The airway was measured from the nasopharyngeal level to tongue-base level, and the average cross-sectional area was calculated from the volume and length of the airway. To obtain the area, antero-posterior diameter, and width measurements, cross-sections at four levels were selected in the upper airway; i.e., nasopharyngeal level, hard-palate level, oropharyngeal level, and tongue-base level. In order to evaluate the correlation between maxillofacial and pharyngeal morphology, cephalometric analysis was carried out using lateral cephalograms. The subjects were divided into two groups based on skeletal deformities of Class II and Class III from the results of cephalometric analysis, and the differences in pharyngeal morphology between the two groups were investigated statistically. The significance level was set at P < 0.05. The average volume and average cross-sectional area of the pharyngeal airway was 15.71 ± 5.36 cm³ and 2.23 ± 0.74 cm² respectively. Our results revealed that the area at the oropharyngeal level mostly contributed to the size of the pharyngeal airway. It was demonstrated that the area and anteroposterior length at the palatal level in the skeletal Class II group were significantly smaller than those in the skeletal Class III group. Even though no statistical significance was found between the two groups, the width of the airway in the hard-palate level and antero-posterior length in the oropharyngeal level showed a possible statistical correlation with some cephalometric measurement values, indicating that there could be some relationship between airway and maxillofacial morphology.

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This study investigates the effects of sagittal split ramus osteotomy (SSRO) on condylar position and temporomandibular joint (TMJ) symptoms.
The subjects were 51 patients (13 males and 38 females) in whom mandibular protrusions were corrected by SSRO; they were divided into three subtypes on the basis of the lateral bone cut location. The joints were examined clinically for pain, sound and maximum interincisal opening before surgery and at least six months after surgery. Submentovertex radiographs were taken before and immediately after surgery. The changes in condylar position were assessed by measuring the condylar angle, intercondylar axes angle and distance between the centers of the condyles.
After SSRO, the condyles rotated inward (p < 0.01) on the axial plane, but the distances between their centers did not change significantly. TMJ signs and symptoms disappeared in four (31%) of the 12 symptomatic patients, worsened in one (8%) of the symptomatic patients and developed in three (8%) of the 39 asymptomatic patients six months after surgery. There were no significant differences in any of the parameters among the three subtypes of SSRO.

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[Purpose] This study examines using ultrasonography and unenhanced computed tomography (CT) to determine the location of the internal maxillary artery (IMA) before orthognathic surgery.
[Patients and Methods] From January 2008 to February 2011, 15 patients (30 sides as bilateral) with jaw deformities agreed to participate in this study after informed consent was obtained. IMAs were visualized through the acoustic window formed by the zygomatic arch and mandibular notch using power Doppler ultrasonography. Ultrasonographic findings were classified into 2 patterns as follows: 1) clear pattern, indicating continuous or string-like structure; 2) unclear pattern, indicating discontinuous dot-like structure or no apparent blood flow. Each unenhanced CT image of the IMA location was categorized referring to the ultrasonographic image as predictable or unpredictable.
In addition, each predictable image was subclassified as lateral (located external to the lateral pterygoid muscle) or medial (other than the former).
[Results] The ultrasonography had 24 (80.0%) IMAs classified as clear and 6 (20.0%) as unclear. For the 24 clear patterns, the mean distance from the mandibular notch to the IMA was 2.77 mm (1.0-6.0 mm). The IMA location was detectable in all patients using unenhanced CT plus ultrasonographic imaging. Of the 26 (86.7%) IMAs located lateral to the lateral pterygoid muscle, the ultrasonographic artery findings were classified as clear for 24 and unclear for 2. Of the 4 (13.3%) IMAs located medial to the lateral pterygoid muscle, the ultrasonography findings were classified as unclear.
[Discussion] Paying attention to unclear-pattern images classified as lateral was necessary because they may indicate that the IMA is located in proximity to the ramus medially, and to clear-pattern images classified as lateral that approach the mandibular notch. We assume that the risk for hemorrhage during orthognathic surgery will increase if the IMA route is located in the surgery area.
[Conclusion] A combination of ultrasonography and unenhanced CT for determining the IMA route may provide safer orthognathic surgery.

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The clinical efficacy and safety of new resorbable plate and screw fixation devices for maxillary stabilization in orthognathic surgery were evaluated in this study. The plate and screw fixation devices were fabricated from a unique tripolymer composed of poly L-Lactide/D-Lactide/Glycolide with a molecular ratio of 85/5/10. From August 2002 to May 2003, we conducted a clinical trial, using the resorbable devices for fixation of the maxilla at osteotomy sites of thirty patients. In all patients, the fixation of bony fragments was evaluated at the time of the operation, and the postoperative course and complications were evaluated by clinical and CT findings and by blood and urine examinations for 6 months following surgery.
All patients had satisfactory results from surgery. While none of the patients had any evidence of adverse tissue reactions such as facial swelling, erythema, and/or radiographic osteolysis at 6 months after surgery, mild tenderness remained at three implantation sites in two patients in the clinical evaluation. Blood and urine examination showed no evidence of a cause-and-effect relationship between abnormal examination values and fixation devices. In radiographic evaluations at 6 months after surgery, bone adhesions were obscure in sixteen patients, but the fixations were maintained in all cases. These results of clinical and radiographic evaluations provide evidence that osteosynthesis can be safely and effectively completed in fixation of the maxilla with the resorbable plate and screw fixation devices.

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