Objective: In Le Fort I osteotomy, accidental pterygoid process fracture (ppfx) in case of pterygomaxillary disjunction is associated with occasional severe hemorrhage, so it is important to predict ppfxs before Le Fort I osteotomy. From the results of a detailed analysis of preoperative quantitative evaluation of morphometric values, we have reported four risk factors of ppfx: a thinner pterygomaxillary junction, a longer maxillary tuberosity, male and high age. Therefore, we prospectively examined whether the risk factors are applicable to cases of not only maxillary retrusion but also facial asymmetry with deformation reaching the maxilla, as well as the characteristics of high-risk cases of ppfx.
This study aimed to identify the high-risk group of ppfx, using the four risk factors obtained from our previous research.
Study Design: Clinical and anatomical data from preoperative computed tomography images were obtained. The correlation between these data and ppfx was examined. We divided the four groups based on the number of risk factors, then classified the high-risk group of ppfx.
Results: The group of pterygomaxillary junction thickness less than 2.6mm had a significantly higher risk of ppfx. In addition, cases having more than three or four factors were classified as the high-risk group.
Conclusions: In this study, a newly discovered high-risk group of ppfx was proposed. Prediction of frangible pterygoid plates by preoperative quantitative evaluation of morphometric values is likely to be useful for selecting safe procedures.

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A clinical analysis was performed on 231 patients with jaw deformities who had undergone orthognathic surgery in the Department of Oral and Maxillofacial Surgery, School of Dentistry, Health Sciences University of Hokkaido from November 2002 to March 2017. The results were as follows:
1. The patients were 63 males and 168 females (male to female ratio of 1:2.66).
2. The mean age at the time of operation was 25.4±10.0 years (range: 15–58 years).
3. The diagnosis of mandibular prognathism was made for most patients (125 cases: 54.1%).
4. The most common surgical method was sagittal split ramus osteotomy (SSRO) (133 cases: 55.6%), followed by the combination of Le Fort I osteotomy (LF I)+SSRO (51 cases: 21.3%).
5. The average time of operation for SSRO was 133.7±36.5 minutes and that for SSRO+LF I was 282±57.4 minutes.
6. The average amount of bleeding was 143.7±188.5ml for SSRO and that for SSRO+LF I was 266.9±184.3ml.
7. Blood transfusion was performed in about 13.8% of the patients, and all cases were preoperative hemodilution autotransfusion.

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Objective: Two-jaw surgery is often performed in patients with facial asymmetry to improve malocclusion and facial esthetics. However, undesired changes of the nasal morphology may collaterally occur due to repositioning of the maxillary bone. The purpose of this study was to investigate the influence of two-jaw surgery on nasal morphology in orthognathic patients with facial asymmetry using 3-dimensional computed tomography (3D-CT) image analysis.
Materials and Methods: Twelve patients (7 females and 5 males, mean age at the time of surgery: 24.3±5.9 years) with facial asymmetry who had undergone two-jaw surgery were enrolled. Pre-surgical facial 3D-CT images (T₁) were superimposed on images obtained 4 months post-surgery (T₂) using 3D imaging software. The 3D coordinate system constructed by Frankfurt horizontal (FH) plane was used for the analysis, including the frontal plane, incorporating orbits on both sides, and the sagittal plane, intersecting at the midpoint between the orbits. After superimposing the T₁ and T₂ images, soft-tissue 3D-CT images were reconstructed, and changes in external nasal morphology were analyzed. Furthermore, linear and angular measurements of hard and soft tissues, as well as measurements of the external nasal aperture area were obtained and compared between T₁ and T₂.
Results: T₂ images showed anterior placement of nasal area soft tissues resulting in widening of the nasal wing, and a significant reduction in canting of the alar base and the lip. The external nasal aperture area was similar between the shifted and non-shifted sides at T₁. At T₂, the nasal aperture was significantly increased in both the shifted and non-shifted sides, but the aspect of change was the same. Positive correlations were seen between the horizontal/vertical movement of ANS and nasal soft tissues, and between the cant of the occlusal plane and the alar base.
Conclusion: The study showed that two-jaw surgery is an effective treatment modality for patients with facial asymmetry. However, since nasal area soft tissues were correlated with movement of ANS, the effect of maxillary movement on nasal soft tissues must be considered when making the treatment plan.

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Orthognathic surgery has recently become a significant element in the field of oral surgery. Owing to factors such as advancements in surgical techniques and the development and improvement of surgical equipment, orthognathic surgery is becoming increasingly safe; however, intraoperative blood loss can still pose a difficult problem in some cases. Therefore, we examined whether tranexamic acid (TXA) can reduce intraoperative blood loss during orthognathic surgery.
The initial group of subjects in this prospective, randomized controlled trial comprised 377 individuals who underwent orthognathic surgery at the Department of Stomatology, Tokyo Metropolitan Ohtsuka Hospital between April 2006 and March 2017. After excluding patients with congenital anomalies (e.g., cleft lip and palate), combined surgery patients, patients with intraoperative complications, reoperation patients, and patients with incomplete intraoperative records, 270 patients were ultimately included in the analysis. Of these 270 patients, 171 underwent sagittal split ramus osteotomy (SSRO) and 99 underwent Le Fort I osteotomy and SSRO (LF I+SSRO).
The subjects were randomly assigned to a TXA group or a control group. The optimal dose of TXA was set at 20mg/kg. Patients who underwent SSRO were classified into two groups: a TXA₂₀ group, which received TXA 20mg/kg immediately prior to surgery, and a control group. Patients who underwent LF I+SSRO were classified into three groups: a TXA₂₀ group, which received a single administration of TXA 20mg/kg immediately prior to maxillary osteotomy; a TXA₁₀₊₁₀ group, which received two separate administrations of TXA 10mg/kg immediately prior to maxillary and mandibular osteotomy; and a control group. Groups were compared in terms of age, male/female ratio, body mass index, body surface area, surgical time, total intraoperative blood loss, and intraoperative blood loss per hour of surgery.
Of the patients who underwent SSRO, there was no significant difference in any variable between the two groups. Of the patients who underwent LF I+SSRO, there was no significant difference in total intraoperative blood loss between the TXA₂₀ group and the control group. However, when patients who underwent LF I+SSRO were reclassified based on surgical time, a significant difference was observed in the total intraoperative blood loss in the long surgical time group. In addition, a significant difference was observed in intraoperative blood loss per hour of surgery between the TXA₁₀₊₁₀ group and the control group. These results suggest that TXA may be able to reduce intraoperative blood loss during orthognathic surgery.

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An 18-year-old male with fibrous dysplasia of the right mandible was referred to our department for correction of facial asymmetry and scissors bite of the right molars. We planned posterior segmental osteotomy of the right maxilla and mandible after navigation-guided removal of the right bulging mandible. Mandibular navigation surgery was performed with an occlusal splint with titanium markers and reference frame, and facial symmetry was acquired postoperatively. Preoperative orthodontic treatment was performed, and posterior segmental osteotomy of the right mandible and maxilla combined with Le Fort I osteotomy was performed for correction of the scissors bite 1 year after navigation surgery for bone reduction. Postoperative orthodontic treatment has been performed for 9 months. Facial symmetry and ideal occlusion of the right molar area has been maintained for more than 3 years.

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Acromegaly is a hormonal disorder that results from excess growth hormone (GH) after the growth plates have closed. Surgical orthodontic treatment has often been performed since many cases have abnormal growth of the tongue and jaw bone. We report a case of acromegaly for which surgical orthodontic treatment was performed.
The patient was a 28-year-old man with mandibular prognathism. His main complaints were occlusal disorder and mandibular prognathism. Surgical orthodontic treatment was performed after surgical treatment for acromegaly. Since there was no sign of acromegaly after surgery, a combination of Le Fort I osteotomy and bilateral sagittal split osteotomy was performed after preoperative orthodontic treatment to correct the jaw deformity. The occlusal relationship was stable and there was no recurrence at two years after surgery.
Orthognathic surgery for patients with acromegaly has usually been bilateral sagittal splitting osteotomy in Japan, and tongue reduction has also been carried out simultaneously in many cases. A combination of Le Fort I osteotomy and bilateral sagittal split osteotomy has been increasingly performed in recent years. The outcomes have been good in almost all cases including the present case. However, there have been some reports of recurrence of acromegaly, and long-term follow-up is therefore necessary after orthognathic surgery.

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Orthognathic surgery is a widely recognized procedure for treating patients with jaw deformities, and the number of such patients who have underlying diseases or have an implantable cardioverter defibrillator (ICD) has been increasing. We report treatment management for orthognathic surgery in two patients with jaw deformities who had ICDs and indicate important points that require attention when treating patients with jaw deformities who have ICDs.
One patient was a 51-year-old male with mandibular prognathism who had received an ICD for Brugada syndrome. He experienced proper ICD function against ventricular fibrillation (VF) and began taking quinidine hydrochloride after that event. We decided that surgery under general anesthesia would be possible without deterioration of cardiac function and we started treatment. After preoperative orthodontic treatment, Le Fort 1 osteotomy and bilateral sagittal split ramus osteotomy (BSSRO) were performed. Preoperative examination showed no abnormalities except for a coved ST-segment elevation in the V1 lead and saddleback ST-segment elevation in the V3 lead. He continued taking quinidine hydrochloride during his hospital stay. The use of the ICD was discontinued and a defibrillator patch was applied to the chest during surgery, and there was no arrhythmia requiring defibrillation. The ICD was reset after surgery and no surgical ICD procedure was carried out during his hospital stay.
The other patient was a 38-year-old male with mandibular prognathism who had an ICD for idiopathic VF. He experienced proper ICD function against VF probably caused by vasospastic angina and began taking benidipine hydrochloride after that event. We decided that surgery under general anesthesia would be possible without deterioration of cardiac function and we started treatment. Presurgical orthodontic treatment was followed by Le Fort 1 osteotomy and BSSRO. He had no abnormalities on preoperative examination and continued taking benidipine hydrochloride during his hospital stay. The use of the ICD was discontinued and a defibrillator patch was applied to the chest. Nicorandil was administered continuously to prevent coronary artery spasms during the surgery, and there was no arrhythmia requiring defibrillation. The ICD was reset after surgery and no surgical ICD procedure was carried out during his hospital stay.
We conclude that in the treatment of jaw deformities in patients who have ICDs, 1) planning of the treatment according to the cardiac function of each patient, 2) device management (prevention of malfunction), and 3) prevention of life-threatening arrhythmias caused by the disease state are important.

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