A safe, stable, and convenient three-dimensional device for high Le Fort I osteotomy

Sugahara, Keisuke,Koyachi, Masahide,Odaka, Kento,Matsunaga, Satoru,Katakura, Akira Korean Association of Maxillofacial Plastic and Re 2020 Maxillofacial Plastic Reconstructive Surgery Vol.42 No.-

Background: Le Fort I osteotomy is a highly effective treatment for skeletal jaw deformities and is commonly performed. High Le Fort I osteotomy is a modified surgical procedure performed for improving the depression of the cheeks by setting the osteotomy higher than the conventional Le Fort I osteotomy. Developments in three-dimensional (3D) technology have popularized the use of 3D printers in various institutions, especially in orthognathic surgeries. In this study, we report a safe and inexpensive method of performing a high Le Fort I osteotomy using a novel 3D device and piezosurgery, which prevent tooth root injury without disturbing the operation field for patients with a short midface and long tooth roots. Results: A 17-year-old woman presented with facial asymmetry, mandibular protrusion, a short midface, and long tooth roots. We planned high Le Fort I osteotomy and bilateral sagittal split ramus osteotomy. Prevention of damage to the roots of the teeth and the infraorbital nerve and accurate determination of the posterior osteotomy line were crucial for clinical success. Le Fort I osteotomy using 3D devices has been reported previously but were particularly large in size for this case. Additionally, setting the fixing screw of the device was difficult, because of the risk of damage to the roots of the teeth. Therefore, a different surgical technique, other than the conventional Le Fort I osteotomy and 3D device, was required. The left and right parts of the 3D device were fabricated separately, to prevent any interference in the surgical field. Further, the 3D device was designed to accurately cover the bone surface from the piriform aperture to the infra-zygomatic crest with two fixation points (the anterior nasal spine and the piriform aperture), which ensured stabilization of the 3D device. The device is thin and does not interfere with the surgical field. Safe and accurate surgical performance is possible using this device and piezosurgery. The roots of the teeth and the infraorbital nerve were unharmed during the surgery. Conclusions: This device is considerably smaller than conventional devices and is a simple, low-cost, and efficient method for performing accurate high Le Fort I osteotomy.

Mixed reality for extraction of maxillary mesiodens

Yu Koyama,Masahide Koyachi,Kotaro Tachizawa,Akira Iwasaki,Ichiro Wakita,Akihiro Nishiyama,Satoru Matsunaga,Akira Katakura,Keisuke Sugahara 대한악안면성형재건외과학회 2023 Maxillofacial Plastic Reconstructive Surgery Vol.45 No.-

Background Mesiodentes are the most common supernumerary teeth. The cause is not fully understood, although proliferations of genetic factors and the dental lamina have been implicated. Mesiodentes can cause delayed or ectopic eruption of permanent incisors, which can further alter occlusion and appearance. Careful attention should be paid to the position and direction of the mesiodentes because of possible damage to adjacent roots in the permanent dentition period, errant extraction in the deciduous and mixed dentition periods, and damage to the permanent tooth embryo. To avoid these complications, we applied mixed reality (MR) technology using the HoloLens® (Microsoft, California). In this study, we report on three cases of mesiodentes extraction under general anesthesia using MR technology. Results The patients ranged in age from 6 to 11 years, all three were boys, and the direction of eruption was inverted in all cases. The extraction approach was palatal in two cases and labial in one case. The average operative time was 32 min, and bleeding was minimal in all cases. No intraoperative or postoperative complications occurred. An image was shared preoperatively with all the surgeons using an actual situation model. Three surgeons used Microsoft Holo- Lens® during surgery, shared MR, and operated while superimposing the application image in the surgical field. Conclusions The procedure was performed safely; further development of MR surgery support systems in the future is suggested.

Novel condylar repositioning method for 3D-printed models

Sugahara, Keisuke,Katsumi, Yoshiharu,Koyachi, Masahide,Koyama, Yu,Matsunaga, Satoru,Odaka, Kento,Abe, Shinichi,Takano, Masayuki,Katakura, Akira Korean Association of Maxillofacial Plastic and Re 2018 Maxillofacial Plastic Reconstructive Surgery Vol.40 No.-

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.

A clinico-statistical study of factors associated with intraoperative bleeding in orthognathic surgery

Keisuke Sugahara,Yu Koyama,Masahide Koyachi,Akira Watanabe,Kiyohiro Kasahara,Masayuki Takano,Akira Katakura 대한악안면성형재건외과학회 2022 Maxillofacial Plastic Reconstructive Surgery Vol.44 No.-

Background: Excessive bleeding is a major intraoperative risk associated with orthognathic surgery. This studyaimed to investigate the factors involved in massive bleeding during orthognathic surgeries so that safe surgeriescan be performed. Patients (n=213) diagnosed with jaw deformities and treated with bimaxillary orthognathicsurgery (Le Fort I osteotomy and bilateral sagittal split ramus osteotomy) in the Department of Oral andMaxillofacial Surgery at the Suidobashi Hospital, Tokyo Dental College between January 2014 and December 2016were included. Using the patients’ medical and operative records, the number of cases according to sex, age at thetime of surgery, body mass index (BMI), circulating blood volume, diagnosis of maxillary deformity, direction ofmaxillary 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 wereassociated with the risk of intraoperative massive bleeding in orthognathic surgeries. Chi-square tests and binomiallogistic regression analyses showed significant differences in BMI, circulating blood volume, direction of maxillarymovement, operative duration, and injury to the nasal mucosa. Operative duration emerged as the most important riskfactor. Furthermore, a >4-mm upward migration of the posterior nasal spine predicted the risk of massive bleeding inorthognathic surgery. Conclusions: The upward movement of the maxilla should be recognized during the preoperative planning stage as arisk factor for intraoperative bleeding, and avoiding damage to the nasal mucosa should be considered a requirementfor surgeons to prevent massive bleeding during surgery

Maxillary reconstruction using tunneling flap technique with 3D custom-made titanium mesh plate and particulate cancellous bone and marrow graft: a case report

Takano, Masayuki,Sugahara, Keisuke,Koyachi, Masahide,Odaka, Kento,Matsunaga, Satoru,Homma, Shinya,Abe, Shinichi,Katakura, Akira,Shibahara, Takahiko Korean Association of Maxillofacial Plastic and Re 2019 Maxillofacial Plastic Reconstructive Surgery Vol.41 No.-

Background: Reconstructive surgery is often required for tumors of the oral and maxillofacial region, irrespective of whether they are benign or malignant, the area involved, and the tumor size. Recently, three-dimensional (3D) models are increasingly used in reconstructive surgery. However, these models have rarely been adapted for the fabrication of custom-made reconstruction materials. In this report, we present a case of maxillary reconstruction using a laboratory-engineered, custom-made mesh plate from a 3D model. Case presentation: The patient was a 56-year-old female, who had undergone maxillary resection in 2011 for intraoral squamous cell carcinoma that presented as a swelling of the anterior maxillary gingiva. Five years later, there was no recurrence of the malignant tumor and a maxillary reconstruction was planned. Computed tomography (CT) revealed a large bony defect in the dental-alveolar area of the anterior maxilla. Using the CT data, a 3D model of the maxilla was prepared, and the site of reconstruction determined. A custom-made mesh plate was fabricated using the 3D model (Okada Medical Supply, Tokyo, Japan). We performed the reconstruction using the custom-made titanium mesh plate and the particulate cancellous bone and marrow graft from her iliac bone. We employed the tunneling flap technique without alveolar crest incision, to prevent surgical wound dehiscence, mesh exposure, and alveolar bone loss. Ten months later, three dental implants were inserted in the graft. Before the final crown setting, we performed a gingivoplasty with palate mucosal graft. The patient has expressed total satisfaction with both the functional and esthetic outcomes of the procedure. Conclusion: We have successfully performed a maxillary and dental reconstruction using a custom-made, pre-bent titanium mesh plate.

Retromandibular vein position and course patterns in relation to mandible: anatomical morphologies requiring particular vigilance during sagittal split ramus osteotomy

Keisuke Sugahara,Satoru Matsunaga,Masahito Yamamoto,Taku Noguchi,Sumiharu Morita,Masahide Koyachi,Yu Koyama,Takumi Koyama,Norio Kasahara,Shinichi Abe,Akira Katakura 대한해부학회 2020 Anatomy & Cell Biology Vol.53 No.4

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.

Clinical investigation of patients with jaw deformity with comorbidities

Kiyohiro Kasahara,Teruhide Hoshino,Kei Sugiura,Yuki Tanimoto,Masahide Koyachi,Masae Yamamoto,Keisuke Sugahara,Masayuki Takano,Akira Katakura 대한악안면성형재건외과학회 2022 Maxillofacial Plastic Reconstructive Surgery Vol.44 No.-

Background: With improvements in the safety and stability of surgeries, the number of orthognathic surgeries isincreasing. Most patients who undergo orthognathic surgeries are younger, and the number of orthognathic surgeriesfor patients with comorbidities is also increasing. We report a survey and clinical investigation of patients withcomorbidities who underwent orthognathic surgeries at our department to improve the safety of orthognathicsurgery. Results: The participants included 296 men and 712 women, with a mean age of 28 years (13?19 years, n=144;20?29 years, n=483; 30?39 years, n=236; 40?49 years, n=102; 50?59 years, n=39; ≥60 years, n=4). In total, 347patients underwent one-stage Le Fort type I osteotomy and sagittal split ramus osteotomy (SSRO), 243 underwentSSRO, 287 underwent plate removal, 126 underwent genioplasty and plate removal, and five underwent othersurgeries. In total, 529 patients had comorbidities (52%), including allergic diseases (n=220, 33%), respiratory diseases(n=107, 16%), neurologic and psychiatric diseases (n=69, 10%), gynecologic diseases (n=28, 4%), hematologicdiseases (n=27, 4%), cardiovascular diseases (n=24, 4%), digestive diseases (n=22, 3%), metabolic and endocrinediseases (n=18, 3%), spinal diseases (n=11, 2%), ophthalmologic diseases (n=11, 2%), renal and urological diseases(n=9, 1%), and other diseases (n=117, 18%). Among the patients with comorbidities, 11 with hemorrhagic diatheses(hemophilia and von Willebrand disease), arrhythmia (atrioventricular block), psychiatric disease (adjustment disorder),and metabolic disease (diabetes) required cautious perioperative management. The patient with hemophilia wasmanaged with regular low-dose recombinant factor VIII replacement therapy, and the patient with type I diabetesmellitus was administered continuous insulin infusion and sliding-scale insulin therapy; both patients had an uneventfulcourse. Conclusions: The study findings suggest that with the increase in orthognathic surgeries, oral and maxillofacialsurgeons should adequately manage cases requiring cautious perioperative control and highlight the importance ofpreoperative screening. Despite the well-established safety and postoperative stability of orthognathic surgeries, oralsurgeons should adopt appropriate additional preventive measures for patients with comorbidities.