Etsuhide Yamamoto

Kanazawa University, Kanazawa, Ishikawa, Japan

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Publications (241)332.8 Total impact

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    ABSTRACT: Simple bone cysts rarely occur in the mandibular ramus and are extremely rare in early childhood. We report a recurrent case of a simple bone cyst in an infant. A 4-year-old boy was referred to our department because of swelling of the left cheek. A clinical examination confirmed left cheek swelling and bone expansion of the mandibular ramus. Radiographs showed a large radiolucent, monolocular lesion in the left mandibular ramus, and thinning and bulging of the buccal cortical bone was confirmed. A clinical diagnosis of mandibular cyst was made. Surgical treatment was carried out and revealed serious fluid with no cyst wall in the bone cavity. Alternatively, we diagnosed the lesion as a simple bone cyst. Although radiographic follow-up indicated new bone regeneration, the cystic lesion recurred 4 years 3 months after surgery. Surgical treatment was performed again, and the pathological diagnosis was a simple bone cyst. The mandible showed osseous healing, and there was no recurrence 2 years after the second operation.
    Preview · Article · Jan 2014 · Nippon Koku Geka Gakkai zasshi

  • No preview · Article · Oct 2011 · International Journal of Oral and Maxillofacial Surgery
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    ABSTRACT: The aim of this study was to evaluate hypoaesthesia of the lower lip and bone formation using self-setting α-tricalcium phosphate (Biopex(®)) between the proximal and distal segments following sagittal split ramus osteotomy (SSRO) with bent absorbable plate fixation. The subjects were 40 patients (80 sides) who underwent bilateral SSRO setback surgery. They were divided into a Biopex(®) group (40 sides) and a control group (40 sides). The Biopex(®) was inserted into the anterior part of the gap between the segments in the Biopex(®) group. Trigeminal nerve hypoaesthesia in the region of the lower lip was assessed bilaterally using the trigeminal somatosensory-evoked potential (TSEP) method. Ramus square, ramus length, and ramus width, the square of the Biopex(®) at the horizontal plane under the mandibular foramen were assessed preoperatively, immediately after surgery, and 1year postoperatively by computed tomography (CT). The mean measurable period and standard deviation were 9.3±15.7weeks in the control group, 5.3±8.3weeks in the Biopex(®) group, and there was no significant difference. Ramus square after 1year was significantly larger than that prior to surgery and new bone formation was found between the segments in both groups (P<0.05). In the Biopex(®) group, the square of the Biopex(®) after 1year was significantly smaller than that immediately after surgery (P<0.05). This study suggested that inserting Biopex(®) in the gap between the proximal and distal segments was useful for new bone formation and it did not prevent the recovery of lower lip hypoaesthesia after SSRO with bent absorbable plate fixation.
    No preview · Article · Aug 2011 · Journal of cranio-maxillo-facial surgery: official publication of the European Association for Cranio-Maxillo-Facial Surgery
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    ABSTRACT: It is well documented that the binding of urokinase-type plasminogen activator (uPA) to its receptor (uPAR), which has been implicated in cancer invasion and metastasis, is regulated by several inhibitors such as maspin. In this study, we investigated the interrelationship between clinicopathologic findings and expression of uPA, uPAR and maspin in oral squamous cell carcinoma (OSCC) to elucidate the participation of maspin in the uPA/uPAR system in the malignant behavior of OSCC. Using immunohistochemical techniques to examine the expression levels of uPA, uPAR and maspin in 54 cases of OSCC, we also compared the clinicopathologic features of OSCC with the expression levels of each. Moreover, we examined the expression of uPA, uPAR and maspin in six cell lines derived from OSCC using reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting. uPA and uPAR showed a positive correlation with the mode of cancer invasion; conversely maspin showed a negative correlation with the mode of invasion. Multivariate analysis revealed that only two factors (N-category and uPA+/uPAR+/maspin- expression pattern) were significant and independent variables with relative risks of 3.84 and 2.52, respectively. In particular, tumors exhibiting an expression pattern of uPA+/uPAR+/maspin- were highly malignant and were associated with the worst survival rate (5-year overall survival rate, 29.4%), while tumors with an expression pattern, uPA-/uPAR-/Μaspin+, showed the most favorable survival rate (5-year overall survival rate, 77.8%). In vitro, lower expression of maspin was also noted in the cell lines derived from grade 4D OSCC, which exhibited a stronger invasive potential than the cells lines derived from the other grades of OSCC, while uPA and uPAR demonstrated an expression trend opposite to maspin. These results indicate that uPA, uPAR and maspin expression patterns may be useful markers for evaluating the clinical course or prognosis of OSCC patients.
    Full-text · Article · Aug 2011 · Oncology Reports
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    ABSTRACT: The purpose of this study was to examine bone healing after Le Fort I osteotomy in Class III patients. The study group consisted of 18 Japanese patients with mandibular prognathism with and without asymmetry, maxillary retrognathism or open bite. A total of 36 sides were examined. Le Fort I osteotomy was performed without a pterygoid osteotome, with an ultrasonic curette used to remove interference at the pterygomaxillary region. Titanium plates (Universal Mid-face fixation module, Stryker, Freiburg, German) were used for four patients, absorbable plates (poly-L-lactic acid (PLLA): NEOFIX(®), Gunze, kyoto, Japan) were used for four patients and other absorbable plates (uncalcined and unsintered hydroxyapatite and poly-L-lactic acid (uHA/PLLA): super FIXSORB(®)MX, Takiron Co. Ltd, Osaka, Japan) were used for 10 patients, in the same manner. Postoperative computed tomography (CT) was analyzed for all patients pre-operatively and 1 year postoperative. The anterior and lateral areas between the maxillary segments were measured with 3-dimensional (3D) CT. Bone healing at the pterygomaxillary region was also assessed. There were no significant differences in the area of bone defect healing among the plate types. The areas of bone defect after 1 year were significantly smaller than that immediately after surgery on the right side (p=0.0145) and left side (p=0.0010) in the frontal view and right side in the lateral view (p=0.0118). Bone healing at the pterygomaxillary junction was found in all cases without artificial pterygoid plate fracture. Fourteen of 22 sides with artificial pterygoid plate fracture by an ultrasonic curette showed bone continuity between the pterygoid plate and posterior part of maxilla. This study suggested that bony healing could occur in spaces between the segments of maxilla and pterygomaxillary regions as well as the region of the anterior and lateral walls in the maxilla, but it is not always complete within 1 year after Le Fort I osteotomy.
    Preview · Article · Jun 2011 · Journal of cranio-maxillo-facial surgery: official publication of the European Association for Cranio-Maxillo-Facial Surgery
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    ABSTRACT: The purpose of this study is to compare the time-course changes in condylar long-axis and skeletal stability after sagittal split ramus osteotomy (SSRO) with an unsintered hydroxyapatite (u-HA)/poly-L-lactic acid (PLLA) plate, PLLA plate, or titanium plate. Of 60 Japanese patients diagnosed with mandibular prognathism, 20 underwent SSRO with a u-HA/PLLA plate system, 20 underwent SSRO with a PLLA plate system, and 20 underwent SSRO with a conventional titanium plate system. The time-course changes in condylar long-axis and skeletal stability were assessed by use of axial, frontal, and lateral cephalograms. Compared with the u-HA/PLLA group, the titanium group showed a significantly greater change in the right condyle angle between initially and 1 month (P = .0105) and intercondylar axes angle between 1 and 3 months (P = .0013). The PLLA group showed a significantly greater change than the titanium group (P = .0043) and u-HA/PLLA group (P = .0002) in terms of ramus inclination between 1 and 3 months; however, there were no significant differences among the 3 groups in the other measurements for each time interval. This study suggests that there are no significant differences in postoperative time-course changes among a u-HA/PLLA plate system, PLLA plate system, and conventional titanium plate system.
    Preview · Article · May 2011 · Journal of oral and maxillofacial surgery: official journal of the American Association of Oral and Maxillofacial Surgeons
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    ABSTRACT: J Oral Pathol Med (2011) 40: 693–698 Background: Abnormalities in cell-cycle-controlling genes are important in the malignant transformation and proliferation of tumors. Among these genes, the tumor suppressor gene p53 is the most notable, and its mutations provide an indicator of tumor progression and prognosis. Proliferating cell nuclear antigen (PCNA) is a highly conserved nuclear protein that is expressed during cell replication and DNA repair. This study examined the expression of p53 and PCNA at the invasive front of oral squamous cell carcinomas (OSCC) by immunohistochemical staining, and investigated the relationship of these proteins to clinicopathological findings and prognosis. Methods: Fifty-nine biopsy cases of OSCC were examined by immunohistochemical staining. Clinicopathological data were gathered and patient survival was analyzed. Results: The p53 labeling index (p53-LI) and PCNA labeling index (PCNA-LI) were examined at the invasive front of the tumors. A high p53-LI (p53+) was observed in 17 of the 59 cases (28.8%) and a high PCNA-LI (PCNA+) was observed in 28 of the 59 cases (47.5%). Among the modes of cancer invasion, many of the p53+/PCNA+ cases could be confirmed as highly invasive cancer (P < 0.05). In addition, the p53+/PCNA+ cases showed a high risk of tumor recurrence compared with the other expression forms, and patients with p53+/PCNA+ had a worse prognosis than those with the other expression forms. High labeling indices of p53 and PCNA are associated with poor prognosis in patients with OSCC. Conclusion: We suggest that it is important to investigate the expression of p53 and PCNA at the invasive front of OSCC.
    No preview · Article · Apr 2011 · Journal of Oral Pathology and Medicine

  • No preview · Article · Feb 2011 · Radiotherapy and Oncology
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    Preview · Article · Dec 2010 · Journal of oral and maxillofacial surgery: official journal of the American Association of Oral and Maxillofacial Surgeons
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    ABSTRACT: The purpose of this study was to evaluate changes in stress on the temporomandibular joint (TMJ) in 80 Japanese subjects (21 males and 59 females, mean age 23.7 years) with mandibular prognathism, with and without asymmetry after orthognathic surgery using the rigid bodies spring model (RBSM). The asymmetric group consisted of 40 subjects whose Mx-Md midline was more than 3 degrees. The remaining 40 subjects formed the symmetric group. The geometry of the stress analysis model was based on frontal cephalograms of the subjects. Menton (Me), the centre point of occlusal force on a line connecting the bilateral buccal cusps of the second molars, and the most lateral, superior, and medial points on the condyle were plotted on a computer display and stress on the condyle was calculated with the two-dimensional RBSM program, Fortran. The degree (force partition) of the resultant force, the direction (angulation), and the displacement (X, Y) of each condyle were calculated and the horizontal displacement (u), the vertical displacement (v), and rotation displacement (theta) of the mandibular body at Me were calculated pre- and post-operatively. The data was analysed using paired and unpaired t-tests. For the vertical (v) and rotational (theta) displacement, the post-operative value was smaller than the pre-operative value (v: P < 0.001, theta: P = 0.0063) in the asymmetric group. For angulation and the X-component, the post-operative value was smaller than that pre-operatively on the deviated (angulation: P = 0.0074, X-component: P = 0.0003) and non-deviated (angulation: P = 0.0024, X-component: P = 0.001) side in the asymmetric group. However, there was no significant difference between the pre- and post-operative value for any parameter in the symmetric group. These findings suggest that surgical correction of mandibular prognathism, with and without asymmetry, could induce an improvement in stress balance on the TMJ in the frontal aspect.
    Preview · Article · Oct 2010 · The European Journal of Orthodontics
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    ABSTRACT: The purpose of this study was to histologically and immuno-histochemically evaluate tissue changes in the maxillary sinus after bone screw implantation and maxillary sinus augmentation using self-setting α-tricalcium phosphate (α-TCP; BIOPEX(®)-R) in rabbit. Adult male Japanese white rabbits (n=15, 12-16 weeks, 2.5-3 kg) were used. The sinus lift was made from the nasal bone of a rabbit. Bone screws (Dual top auto-screw(®)) were implanted into the nasal bone, and after BIOPEX(®)-R was implanted into the left elevated space (operated side) an atelocollagen sponge (ACS: Teruplug(®)) was implanted into the right elevated space (control side). The rabbits were sacrificed at 4, 12 and 24 weeks postoperatively, and formalin-fixed specimens were embedded in acrylic resin. The specimens were stained with hematoxylin and eosin. For immune-histochemical analysis, the specimens were treated with bone morphogenetic protein-2 (BMP-2) antibodies. Finally, these were evaluated microscopically. Tight bonding without fibrous tissue continued between the bone screw and BIOPEX(®)-R, and the rigidity of the bone screw in the nasal bone was retained for 24 weeks in all cases. The area ofnew bone formation increased gradually on both sides; however, there was no significant difference between both sides at 4, 12 and 24 weeks. The number of BMP-2-stained cells on the experimental side was significantly larger than that on the control side after 4 weeks (P=0.0361). This study suggested the usefulness of self-setting α-TCP (BIOPEX(®)-R) to maintain the rigidity of implanted bone screws from an early period, and the result of BMP-2 expression suggested that BIOPEX(®)-R could have bone-conductive activity in the maxillary sinus augmentation.
    No preview · Article · Oct 2010 · Clinical Oral Implants Research
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    ABSTRACT: The purpose of this study was to evaluate changes in the mandibular canal and ramus morphology before and after a sagittal split ramus osteotomy. The subjects were 30 patients (60 sides) with mandibular prognathism who had undergone bilateral sagittal split ramus osteotomy setback surgery. The mandibular canal position and ramus morphology were measured at the 3 horizontal planes under the mandibular foramen level (level A), 1 cm lower than level A (level B), and 2 cm lower than level A (level C) preoperatively and 1 year postoperatively by computed tomography. Postoperative ramus width, lateral distance, lateral marrow distance, and canal length were significantly larger than the preoperative values at the foramen, 1 cm lower, and 2 cm lower. The mandibular canal completely contacted the lateral cortex without lateral bone marrow in 6 sides (10%) in levels A and B and 4 sides (6.7%) in level C preoperatively and 6 sides (10%) in level C postoperatively. This study suggested that postoperative mandibular canal position was located more posteriorly and the postoperative lateral bone marrow became thicker compared with the preoperative state.
    Preview · Article · Aug 2010 · Journal of oral and maxillofacial surgery: official journal of the American Association of Oral and Maxillofacial Surgeons
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    ABSTRACT: The use of the novel oral fluoropyrimidine anticancer drug S-1 as a single agent or in combined chemotherapy has been reported to be useful for the treatment of advanced oral cancer. We report two elderly patients with advanced oral cancer who achieved complete response (CR) after concurrent radiotherapy and S-1 chemotherapy. Patient 1 was an 81-year-old woman who had a 50. mm × 40. mm tumor erosion in the right upper gingival region. At 2.5 years after the end of concurrent radiotherapy and S-1 chemotherapy, tumor relapse was observed, although CR continued temporarily. The patient died 3 years after the end of concurrent radiotherapy and S-1 chemotherapy due to tumor relapse and high blood pressure resulting in deterioration of patient condition. Patient 2 was an 89-year-old woman who had a 40. mm × 30. mm tumor ulcer in the right gingiva. Neither relapse nor metastasis was seen, and patient condition remained good for the 3 years after concurrent radiotherapy and S-1 chemotherapy. In both patients, MRI showed that the tumor had deeply invaded the palatal bone, almost reaching the nasal cavity, with metastasis to the right upper superior internal jugular nodes. In both patients, biopsy showed a well-differentiated squamous cell carcinoma. Concurrent radiotherapy and S-1 chemotherapy induced CR without severe adverse effects. © 2010 Asian Association of Oral and Maxillofacial Surgeons.
    Full-text · Article · Aug 2010 · Asian Journal of Oral and Maxillofacial Surgery
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    ABSTRACT: This study investigated the genotype diversity of Prevotella isolates from dentoalveolar abscess and the genetic relatedness between clinical and commensal isolates within the same patients. Prevotella strains recovered from pus and dental plaque of individual patients (n=9) were examined. Each specimen was inoculated on to blood agar. Six to ten presumptive Prevotella colonies per specimen grown on the primary culture plate were selected. The colonies were genotyped using a random amplified polymorphic DNA assay and the antimicrobial susceptibility profile were also determined. Multiple genotypes per organism were evident in both pus (9 of 9 patients) and plaque (3 of 9 patients). The same genotype was shared by pus and plaque strains in 6 of the 9 patients, while no genetic agreement between pus and plaque strains occurred in the remaining 3 patients. Although it has been suggested that the microflora of infection sites is comprised of genetically homogeneous strains, these findings indicate that a wide range of genetic heterogeneity occurs in infecting Prevotella strains. Furthermore, although dentoalveolar abscess is an opportunistic infection involving endogenous oral bacteria, only certain strains from the commensal population might be involved in the infection.
    No preview · Article · Jan 2010 · Archives of Clinical Microbiology
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    ABSTRACT: Acinic cell carcinoma arising in the palatine salivary glands is relatively rare. We report a case of acinic cell carcinoma arising in the soft palate of a 40-year-old man. The tumor was 10 × 15 mm in size and elastic hard. No swelling of the cervical lymph nodes was palpated. Excision of the tumor was performed with the patient under general anesthesia. Histopathological examination revealed that the parenchyma of the tumor was composed of microcysts. Periodic acid-Schiff (PAS) stain after digestion showed secretory granules in some tumor cells and secretion in dilated lumens. The tumor was diagnosed as a rare atypical case of acinic cell carcinoma showing microcystic and papillary-cystic patterns, characterized by numerous small spaces and prominent cystic spaces, respectively. The postoperative course was uneventful, and there was no evidence of recurrence or metastasis 5 years after surgery.
    No preview · Article · Jan 2010 · Nippon Koku Geka Gakkai zasshi
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    K Ueki · N Takeuchi · K Nakagawa · E Yamamoto
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    ABSTRACT: Aim of this study was to investigate the differences in stress on the temporomandibular joint (TMJ) between Class III patients with and without mandibular asymmetry using a rigid body spring model (RBSM). Menton (Me), the centre point of occlusal force on the line that connected the bilateral buccal cusps of the second molars and the most lateral, superior and medial points of the condyle were plotted on frontal cephalograms, and stress on the condyles was calculated with the 2-dimensional RBSM program of fortran. Eighty Japanese patients with diagnosed mandibular prognathism were divided into two groups, a symmetry group and asymmetry group on the basis of the Mx-Md midline position. The degree (force partition) of the resultant force, the direction (angulation) and displacement (X, Y) of each condyle were calculated. The horizontal displacement vector (u), the vertical displacement vector (v) and rotation angle (theta) of the mandibular body at Menton were also calculated. There were significant differences between the deviated and non-deviated sides of both groups regarding resultant force (symmetry group: p = 0.0372, asymmetry group: p = 0.0054), X (symmetry group: p < 0.0001, asymmetry group: p = 0.0001) and Y (symmetry group: p = 0.0354, asymmetry group: p = 0.0043). For angulation, there was a significant difference between the deviated and non-deviated sides in the asymmetry group (p = 0.0095). The results of this study suggest that difference in stress angulation on the condyles could be associated with asymmetry in mandibular prognathism.
    Preview · Article · Nov 2009 · Orthodontics and Craniofacial Research
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    ABSTRACT: Tumor invasion involves complex interactions between tumor and stromal cells. We examined the extent of connective tissue in the tumor stroma and whether myofibroblasts play a role in assisting cancer invasion and metastasis. Biopsy materials from 84 patients with oral squamous cell carcinoma (SCC) were used. We compared data from intrastromal collagen fibers using Azan staining, immunohistochemical identification of myofibroblasts by cytoskeletal markers, α-smooth muscle actin, vimentin, desmin, and clinicopathological parameters. Clinical outcome was compared by 5-year survival rate. There were high levels of stromal collagen fibers in invasive tumors. Myofibroblast appearance increased with increasing tumor invasiveness. Lymph node metastasis occurred more frequently in the myofibroblast-positive group, and the survival rate was significantly poorer in this group. Fibrous stroma in SCC appeared to have a desmoplastic response. However, an independent invasive mechanism may regulate the stroma, with tumor desmoplasia occurring in highly developed, invasive tumors. © 2009 Wiley Periodicals, Inc. Head Neck, 2009
    Full-text · Article · Oct 2009 · Head & Neck

  • No preview · Article · Sep 2009 · EJC Supplements
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    ABSTRACT: The purpose of this study was to examine the relationship between the morphologies of the masseter muscle and the ramus and occlusal force before and after sagittal split ramus osteotomy (SSRO) in patients with mandibular prognathism. The study group consisted of 26 patients with mandibular prognathism. All patients underwent bilateral SSRO as well as 3-dimensional computed tomography on which the masseter muscle, ramus, and condyle were measured preoperatively and at 1 year postoperation. Occlusal force and contact area were also recorded with pressure-sensitive sheets. In the cross-sectional area of the masseter muscle, there were no significant differences between the pre- and postoperative status. However, postoperative ramus width and area were significantly larger than preoperative values (P < .0001). Postoperative right condylar area was significantly larger than the preoperative value (P = .0120). Occlusal force and contact area 1 year after surgery were significantly larger than the preoperative values (P = .0016, P = .0190). This study suggested that the masseter muscle area did not significantly differ from preoperative status 1 year after SSRO, although occlusal force, contact area, and ramus area and width increased significantly 1 year after SSRO.
    Preview · Article · Aug 2009 · Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology
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    ABSTRACT: To determine the clinical and hisotological efficacy and toxicities of induction chemotherapy with docetaxel (DOC) and nedaplatin (CDGP) for oral squamous cell carcinoma (OSCC) in the preoperative setting. A total of 30 patients with locally advanced but operable OSCC were enrolled. Combination induction chemotherapy consisted of DOC 60 mg/m2 followed by CDGP 100 mg/m2. All patients received one cycle of chemotherapy. In the clinical assessment, ten patients achieved partial response for an overall response rate of 33.3% (95% CI, 16.4-50.2%). Histological assessment of surgical specimens showed an overall response rate of 56.6% (95% CI, 38.9-74.3%). Although severe neutropenia was observed in 90% of patients, only one patient (3.3%) experienced severe infection. Toxicities associated with this regimen did not interfere with planned radical surgery. A single cycle of preoperative combination chemotherapy with DOC and CDGP showed moderate histological activity with an acceptable safety profile for the planned radical surgery. Further studies testing more cycles before surgery might be more appropriate.
    No preview · Article · Aug 2009 · Cancer Chemotherapy and Pharmacology

Publication Stats

5k Citations
332.80 Total Impact Points

Institutions

  • 1993-2011
    • Kanazawa University
      • • Department of Oral and Maxillofacial Surgery
      • • School of Medicine
      Kanazawa, Ishikawa, Japan
  • 1995-2009
    • Kanazawa Medical University
      • Department of Oral and Maxillofacial Surgery
      Kanazawa-shi, Ishikawa-ken, Japan
  • 2001-2002
    • Center For Oral & Maxillofacial Surgery
      Georgia, United States
  • 1983-1984
    • Sapporo Medical University
      • Department of Oral Surgery
      Sapporo, Hokkaidō, Japan