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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.
Numerical Investigation of Suction Performance of Inducer with Splitter Blade
Yohei Tanaka,Satoshi Watanabe,Satoru Ohashi,Yasushi Matsunaga 한국유체기계학회 2020 International journal of fluid machinery and syste Vol.13 No.4
For general-use turbopump inducers, high suction performance is required in a wide operating range including the cutoff point. At the low flow rates, low frequency cavitation surge is known to occur with the strong inlet backflow from the inducer. The reduced inlet blade angle would be favoured for the suppression of this inlet backflow, whereas the reduced inlet blade angle causes the deterioration of suction performance through the reduced inlet throat area. In this study, a splitter blade was adopted for the helical inducer to overcome or relieve these two conflicting problems, and the effectiveness was investigated by CFD considering cavitation. First, the favourable length and the circumferential position of short blade were investigated by 2-D cascade model. Then, the obtained suitable cascade design was applied for the 3-D helical inducer. As a result, the inlet backflow was found to be weakened at the low flow rates as expected, while keeping the good suction performance of inducer in the whole flow rate range.
Takeshi Chida,Kazuhito Kawata,Kazuyoshi Ohta,Erika Matsunaga,Jun Ito,Shin Shimoyama,Satoru Yamazaki,Hidenao Noritake,Tetsuro Suzuki,Takafumi Suda,Yoshimasa Kobayashi 거트앤리버 소화기연관학회협의회 2018 Gut and Liver Vol.12 No.2
Background/Aims: Changes in lipid profiles in patients infected with hepatitis C virus (HCV) during direct-acting antiviral therapy have been reported in recent years. However, the clinical aspects of disturbed lipid metabolism in chronic HCV infection have not been fully elucidated. Methods: Dynamic changes in serum total, low-density lipoprotein (LDL), and high-density lipoprotein (HDL) cholesterol and apolipoprotein levels in patients infected with HCV genotype 1b were examined during combination therapy with daclatasvir (DCV) and asunaprevir (ASV). Results: Total, LDL-, and HDL-cholesterol levels increased rapidly and persistently after week 4. Apolipoprotein (apo) A-I, apo B, apo C-II, and apo C-III levels were significantly higher at week 4 than at week 0. In contrast, apo A-II and apo E levels were significantly lower. The differences in LDL- and HDL-cholesterol levels were positively correlated with those of apo B and apo A-I, respectively. Interestingly, in patients with non-sustained virological response, these cholesterol levels decreased rapidly after viral breakthrough or viral relapse. Furthermore, similar changes were observed for apo A-I, apo B and apo C-III levels. Conclusions: Clearance of HCV using combination therapy with DCV and ASV results in rapid changes in serum lipid profiles, suggesting an influence of HCV infection on disturbed lipid metabolism.
Suction Performance and Cavitation Instabilities of Turbopumps with Three Different Inducer Design
Tatsuya Morii,Yohei Tanaka,Satoshi Watanabe,Satoru Ohashi,Yasushi Matsunaga 한국유체기계학회 2019 International journal of fluid machinery and syste Vol.12 No.2
In the present study, the suction performance and the cavitation instabilities in turbo-pumps with three different inducers designed with different design incidence angle are experimentally investigated in the wide range of operating flow rate. Three inducers L with the lowest design incidence angle, M with the moderate one and H with the largest one are used in combination with identical main impeller. As a result, the total head of pump with inducer H is confirmed to be the largest especially at large flow rates, while the shaft power is almost the same, resulting in the best efficiency with the inducer H. The suction performance is the best with inducer H at large flow rates and is the best with inducer L at low flow rates. Two kinds of instabilities, the cavitating whirling vortex and the surges are mainly observed for the all both inducers, but they are limited at low flow rates. The occurrence ranges of these instabilities in terms of the operating flow rate is the widest with inducer H. However, those in terms of the shockless flow rate ratio is similar for the all three inducers: This fact can contribute to establish some guideline to the pump operation avoiding serious flow instabilities.
Evaluation of Suction Performance of Inducer with Splitter Blade
Yohei Tanaka,Takahiro Kitabata,Satoshi Watanabe,Satoru Ohashi,Akira Sakata,Yasushi Matsunaga 한국유체기계학회 2021 International journal of fluid machinery and syste Vol.14 No.1
For general-use turbopumps with inducer, instability-free operation is required as well as high suction performance in a wide operating range from shut-off to over flow rates. Among the instabilities, the cavitation surge at low flow rates is a very vital phenomenon that is known to be strongly associated with the occurrence of inlet back flow. The low inlet blade angle would be favorable for the suppression of inlet backflow through the reduction of blade loading at the inlet, while the inlet throat area should be kept large for better suction performance to minimize the flow blockage due to cavitation. In the present study, a splitter blade inducer is designed on the basis of the knowledge acquired by our previous CFD study conducted for the 2-D cascade and 3-D straight-hub inducer. Then the effectiveness of the splitter inducer is investigated by experiments and CFD. As a result, the inlet backflow and the cavitation surge are found to be suppressed in the splitter inducer, which is achieved by reducing the blade loading with low inlet blade angle. The suction performance is improved at high flow rates by relaxing the low pressure region with high relative velocity.
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.
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.
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.