Recently, double-jaw surgery is increasing in orthognathic surgery. In such double-jaw surgery, it is important to keep the condylar position at the preoperative position during surgery. Various condylar positioning devices (CPDs) have been reported to obtain stable skeletal and occlusal results. In this study, we investigated the availability of two methods (one step and two steps techniques) for condylar positioning. The subjects were 17 mandibular prognathic patients who underwent double-jaw surgery by a single operator. These 17 patients were divided into the one step technique group (n = 9) and the two steps technique group (n = 8) by the difference of methods for repositioning the mandibular proximal segment. In both groups, ramus inclination and ramus angulation were examined pre- and postoperatively using lateral and posteroanterior cephalograms. Pre- to postoperative changes of these angles were stable in both groups. Statistical analysis revealed no significant difference between the two groups. These results suggest that application of our two CPDs is useful in mandibular prognathic cases undergoing double-jaw surgery. In addition, our CPDs can standardize the procedure of orthognathic surgery without depending on the experience of surgeons.

抄録全体を表示

The purpose of this study was to examine the biomechanical stability on the in vitro model of bilateral sagittal split ramus osteotomy of the mandible (BSSRO). BSSRO was performed on the polyurethane mandible (Mandible teeth clip, SYNBONE^® #8311, SYNBONE AG, Switzerland) by 2 types (angle or parallel) of osteotomy lines with or without bone obstruction. The split rami were fixed by 6 types of osseointegration materials with various designs described as follows: titanium straight locking plate with 4 holes, titanium straight non-locking plate with 4 holes, unsintered hydroxyapatite/poly-L-lactic acid (uHA/PLLA) mesh with 6 holes, uHA/PLLA mesh with 4 holes, uHA/PLLA box with 4 holes, and uHA/PLLA straight plate with 4 holes. The displaced length was measured by 50N and 130N linear compressive load on the bilateral lower first molars with 10mm/min, and those data were statistically analyzed.
The angle osteotomy line was less displaced than the parallel one, and the osteotomy model with bone obstruction was less displaced than that without bone obstruction. In the osteotomy model without bone obstruction, uHA/PLLA mesh fixation showed the least displacement, then titanium plate and uHA/PLLA plate showed less displacement in sequence. In the osteotomy model with bone obstruction, only uHA/PLLA mesh fixation sustained the split mandible. The other plates were fractured by 130N load, which was an approximate value of the occlusal force one month after orthognathic surgery.
These results suggest that the uHA/PLLA mesh with 6 holes fixation can be more stabilized in the osseointegration method than titanium plate fixation for bilateral sagittal split ramus osteotomy of the mandible in certain conditions.

抄録全体を表示

Aim: This study was designed to develop a three-dimensionally integrated model of CBCT craniofacial and dental cast data without any markers in skeletal Class III patients for the ultimate purpose of evaluating soft tissue changes after mandibular setback surgery, and to examine the accuracy of this model.
Materials and methods: The subjects comprised five skeletal Class III female patients who had undergone BSSRO at the average age of 20 years and 6 months.
The materials consisted of CBCT data of the craniofacial hard and soft tissues converted from DICOM format, scanned facial soft tissue data and dental casts of the patients. Facial soft tissue data, which were taken in the condition of exposed gingiva with a cheek retractor, and dental cast data were recorded by two kinds of optimal scanners. These data and lateral cephalometric digital data were taken before orthognathic surgery.
To apply the construction system previously reported, we constructed a craniofacial three-dimensional model by superimposing common regions of each data using Polygon Editing Tool software. First, we superimposed the scanned facial data with exposed gingiva on the CBCT soft tissue data registered at the common regions of the forehead and nose. Then, we superimposed the 3D dental cast data on the previously combined CBCT and scanned facial data by registering at the common frontal gingival region. After cropping each data, we merged the CBCT and dental cast data, and constructed the craniofacial soft and hard tissue three-dimensional integrated model. To examine the precision of this construction, we set three given points on each model. The points were the lower right and left canine cusps, and the lower right central incisal margin.
To examine the repeatability of this model, on the model of case 1, we measured the distance between the ordinary point of the measuring section to each point on CBCT hard tissue data and on dental cast data three times at one-week intervals, and calculated the mean value and standard deviation of the distance between these two positions of each point. To examine the accuracy of integration, we measured the distance between the ordinary point of the measuring section to each point on CBCT hard tissue data and on dental cast data on the models of case 1 to 5, and calculated the mean value and standard deviation of the distance between these two positions of each point.
Results: The mean value of the distance between the positions of each point was less than 0.3mm, and the standard deviation was less than 0.1mm.
Conclusion: The present integrated model of CBCT craniofacial soft and hard tissue data and dental cast data is a simple, low-invasive and highly-accurate method.

抄録全体を表示

The objective of this study was to assess the usefulness of a bioresorbable osteosynthesis system consisting of a hydroxyapatite and poly-L-lactide (HA/PLLA) osteosynthesis system for orthognathic surgery. The subjects were divided into five groups. Group HA/PLLA-Ti consisted of 18 patients who received Le Fort I osteotomy (L1) and bilateral sagittal split osteotomy (SSRO) with an HA/PLLA osteosynthesis system being used for maxillary fixation and a titanium osteosynthesis system being used for mandibular fixation. The HA/PLLA-HA/PLLA group consisted of 4 patients who received L1 and SSRO with an HA/PLLA osteosynthesis system being used for jaw bone fixation. The Ti-Ti group consisted of 37 patients who received L1 and SSRO with a titanium osteosynthesis system being used. A HA/PLLA osteosynthesis system was used for mandibular fixation in 11 patients in the HA/PLLA group and a titanium osteosynthesis system was used in 21 patients in the Ti group in whom SSRO was used for orthognathic surgery. Lateral cephalograms were taken before surgery, immediately after surgery, and at least six months after surgery. Changes in the positions of ANS, point A, point B and Pog were examined. Postoperative changes in the maxilla and mandible were less than 1 mm on cephalograms except for the vertical change at ANS, point B and Pog in the HA/PLLA-HA/PLLA group. There was no significant difference in postoperative skeletal stability among the groups. The tendency to relapse was greater in cases with large surgical movements of the maxilla and/or mandible.
It is concluded that an HA/PLLA osteosynthesis system is clinically useful for orthognathic surgery and maintains postoperative skeletal stability equivalent to that by titanium miniplates.

抄録全体を表示

A survey over a 9-year period from 2005 to 2013 was performed on orthognathic surgery at the Maxillofacial Unit of Oita Oka Hospital.
The results were as follows:
1. The total number of cases of patients who underwent orthognathic surgery under general anesthesia was 394. The annual number of operations has markedly increased since 2005.
2. The male-female ratio was 1: 2.6.
3. The mean age (standard deviation) was 24.5 (8.3) years old.
4. The most predominant diagnosis was mandibular protrusion (60.9% of the cases).
5. Sagittal split ramus osteotomy (SSRO) alone was performed in 79.4% of the cases.
6. The mean operation time and blood loss were 68min (34-305min) and 100ml (10-971ml) in SSRO, 149min (97-276min) and 149ml (10-540ml) in LF-1+SSRO, respectively.
7. The mean duration of hospitalization was 9 days.
8. The introduction rate was 84.1%. The number of participating orthodontic clinics was 23.

抄録全体を表示

Bilateral sagittal split ramus osteotomy is widely used for the surgical treatment of jaw deformity. The present study aimed to compare mastication functions, temporomandibular dysfunctions and neurosensory disturbance of the lower labiomental area during 5 years postoperatively for patients with and without mandibular asymmetry after bilateral sagittal split ramus osteotomy.
A total of 46 women who experienced occlusal improvement following bilateral sagittal split ramus osteotomy were divided into a symmetrical group (n = 22) and an asymmetrical group (n = 24) and evaluated pre- and postoperatively using appropriate testing. The control group consisted of 24 females with individual normal occlusion assessed as having normal masticatory function. Changes in mastication function over time were evaluated based on measurements of occlusal contact area and occlusal force at each evaluation time point. Temporomandibular joint function was evaluated using maximal mouth opening and the Helkimo index. The Semmes-Weinstein monofilament test was used for clinical sensory testing of the lower labiomental area, and differences in degree of sensory disturbance were statistically analyzed.
Marked decreases in function were observed for all evaluation items at 1 month after orthognathic surgery, after which gradual improvements were observed. No significant difference was observed between groups regarding recovery of occlusal contact area. Conversely, recovery of occlusal force was slower in the asymmetrical group than in the symmetrical group, with no significant difference in occlusal force. Helkimo index scores were significantly higher up to 3 months postoperatively in the asymmetrical group compared to the symmetrical group. However, these symptoms subsequently tended to resolve. With regard to neurosensory disturbance of the lower labiomental area, both groups showed considerable paresthesia immediately after surgery, but symptoms tended to subsequently stabilize and marked improvement was seen by 1 year postoperatively, with no significant differences observed between groups.

抄録全体を表示

In this paper, we report the application of bimaxillary surgery for mandibular prognathism in an acromegalic patient with obstructive sleep apnea syndrome (OSAS).
The patient, a 21-year-old male, was referred to our clinic for the treatment of malocclusion with open bite and mandibular protrusion. He was 187cm tall and weighed 68kg. The serum growth hormone (GH) and insulin like growth factor I (IGF-I) showed high scores of 5.86ng/ml and 604ng/ml, respectively. His apnea and hypopnea index was also out of the normal range (16.5). MRI revealed a tumor in the sella turcica. Under the diagnosis of acromegaly caused by pituitary adenoma, he underwent removal of the pituitary tumor by neurosurgeons. Ten months later, IGF-I reduced to the normal range. GH and AHI also decreased. Morphological analysis of the pharynx by using lateral cephalograms revealed widening of his upper airway tract after removal of the pituitary adenoma. Le Fort I and bilateral sagittal splitting ramus osteotomy along with tracheotomy was successfully performed at the age of 24 years. The postoperative course was uneventful. He was followed up for 2 years without skeletal relapse, deterioration of OSAS, or recurrence of pituitary adenoma.

抄録全体を表示

Postoperative nausea and vomiting (PONV) is a typical complication of orthognathic surgery. D2 receptor antagonist is commonly used as an anti-emetic drug, but it also has a potential risk of inducing extrapyramidal reaction. We report a case of acute dystonia probably caused by intravenous infusion of D2 receptor antagonist in a patient with jaw deformity during the perioperative period. The patient was a 21-year-old man who was diagnosed as having maxillary protrusion. He underwent intraoral vertical ramus osteotomy under general anesthesia which was uneventfully performed using sevoflurane and remifentanyl. Immediately following the surgery, droperidol was administered in order to prevent PONV. After emergence, he complained of nausea and D2 receptor antagonist was administered, but had no effect. On the first postoperative day, he showed acute dystonia with nystagmus and opisthotonus. Diazepam was administered and his symptom disappeared. We should pay attention to acute dystonia when using D2 receptor antagonist and need to develop effective management methods for preventing PONV.

抄録全体を表示

Hemifacial microsomia (HFM) is a congenital disorder derived from hypoplasia of the first and second branchial arches that occurs at an incidence in the range of 1 in 3,000 to 5,000 births.
We reported a case of HFM with difficulty in management. The patient, when 9 years old, was treated with distraction osteogenesis in the left mandibular ramus to prevent progression of facial asymmetry. Although facial asymmetry was improved transiently just after early mandibular distraction, mandibular asymmetry with malocclusion was exacerbated due to unharmonious growth of the mandible a few years later. When the patient was 22 years old, sagittal split ramus osteotomy was performed to correct malocclusion after the cessation of mandibular growth. One year later, mandibular angle augmentation was undertaken to improve the asymmetric facial contour using custom-made artificial bone. Computed tomography taken after 2 years of augmentation showed good adaptation as well as bony union between the artificial bone and the mandible. The patient is satisfied with the stable occlusion and better facial contour.

抄録全体を表示

Titanium devices have been frequently used for the osteosynthesis system in orthognathic surgery, and absorbable mini-plates and screws have recently become popular for this system. Among them, bioabsorbable poly-L-lactide (PLLA) mini-plates and screws have gained widespread use in this field. This study reports three cases (one male and two females; aged 19y8m to 30y1m at first visit) who underwent Le Fort I osteotomy and sagittal split ramus osteotomy (SSRO). PLLA mini-plates and screws were used in Le Fort I osteotomy in all cases. Postoperative evaluation was performed by examining cephalograms taken before treatment (T0), at preoperation (T1), immediately after operation (T2), and more than one year after operation (T3). The posterior portion of the maxilla was moved upward after Le Fort I osteotomy to obtain a desirable amount of mandibular setback after SSRO in all cases. All cases showed improved profile and vertical height. There was only little maxillary movement from T2-T3 in both horizontal and vertical dimensions in all cases. All cases showed functional occlusion after the treatment. The present three cases demonstrate that a reliable treatment outcome can be obtained by using PLLA mini-plates and screws in Le Fort I osteotomy.

抄録全体を表示

Airway obstruction is a severe life-threatening perioperative complication of orthodontic surgery. Although hemorrhage and swelling are common after surgery, they are rarely caused by congenital and developmental anomalies of the airway. In the present study, we conducted orthodontic surgery on a patient with first and second branchial arch syndrome associated with bilateral cleft lip, who subsequently developed airway obstruction that might have been caused by an airway malformation. The patient was a 28-year-old male for whom orthodontic surgery for marked mandibular deviation was planned. Surgery involved corticotomy of the anterior maxillary alveolar region and sagittal split ramus osteotomy. After surgery and upon removal of the endotracheal tube, the subject developed wheezing and cyanosis, and so emergency tracheotomy was performed. However, in addition to the airway malformation, left deviation was observed, which made it difficult to clearly visualize the airway. Furthermore, the tracheal cartilage was fragile and easily deformed due to pressure of the flat trachea. After clearly visualizing the airway, an incision was made using a scalpel, which was very easy to perform, similar to making an incision along a blood vessel wall. Tracheomalacia has been described as a possible congenital complication of first and second branchial arch syndrome and the findings in the present case suggest that acquired tracheomalacia was the etiology. In future, after assessing any combined malformations, thorough preoperative evaluations including the airway should be conducted, and preventive tracheotomy should be performed as a postoperative management scheme when necessary, with the consent of the patient.

抄録全体を表示