Published papers

We report a case of auricular malformation treated by placement of an osseointegrated implant-supported epithesis using telenavigation and model simulation. A 66-year-old male suffering from auricular malformation and atresia auris of his right ear since birth visited our department in October 2006. The patient desired placement of an ear epithesis supported by osseointegrated implants. Computed tomographic (CT) scans were obtained for use in the navigation system as a prerequisite for the telenavigation and the operative plan was designed in consultation with an overseas oral and maxillofacial surgeon having rich experience in telenavigation surgery. We also constructed a preoperative simulation model and a mirror model of the unaffected left ear based on laser lithography to produce successful operation and symmetrical form of a symmetrical ear epithesis as contrast with identical to that on the left side. The osseointegrated implant surgery was carried out under telenavigation guidance. As a result, safe and accurate positioning of the implants was achieved and a symmetrical and elaborate epithesis could be fabricated.

Objective: In any immediate reconstruction of the maxillofacial defect after total maxillectomy, the defect is often covered with a flap, however, dentures cannot be maintained stably by the flap, because of the high mobility and large amount of displacement of the flap under pressure. Therefore, we developed a method in which a muscle flap is transplanted without creating a skin island in the oral cavity and a denture is immediately fixed with titanium screws, and obtained favorable results. Patients and methods: The subjects were 9 patients who underwent resection for maxillary sinus cancer. In all patients, a free rectus abdominis muscle flap was used for the reconstruction and the raw surface of the muscle tissue was left in the oral cavity without creating a skin island. Dentures that had been made preoperatively were fixed on the remaining palate and alveolus with titanium screws for one month, so that they covered the muscle tissue. Results: Good palatal morphology was formed without hanging down after epithelialization of the surface of the muscle tissue. In comparison with the preoperative levels, the masticatory and conversational functions recovered to 77% and 90%, on average. Conclusions: Our method is considered to be one of the useful reconstruction methods for maxillofacial defects.

Objective: Transoral approach from the anterior direction is necessary if an upper spinal tumor is too big to extirpate via the posterior approach alone. To obtain a good anterior view of the surgical field, the mandible, tongue, and soft palate have to be split, and we developed a criterion to select the surgical strategy. Study Design: We indicated a decision-making process of splitting techniques and indications with actual cases and review of literatures. Result: Tumors were located from the level of C1 to the lower part of C3. Computerized tomography and magnetic resonance imaging were important to decide approaches. The orthopedic surgical team invited oral and maxillofacial surgeons team to assist in all transoral anterior approach cases. Conclusions: Vertical splitting of the mandible, incising the skin of the mental region, and splitting the middle of the tongue were combined according to the position of the spinal tumor. © 2012 Elsevier Inc. All rights reserved.

We examined the transfer of levofloxacin (LVFX) into serum, gingiva, dental follicles, and mandibular bone following oral administration of a single 500 mg dose of LVFX to 10 subjects, comprising 3 males and 7 females. The mean concentrations 2.0 to 4.5 h after administration in serum, gingiva, dental follicles, and mandibular bone were 4.85 ± 0.82 μg/mL, 7.76 ± 3.21, 7.38 ± 2.04 μg/g, and 2.90 ± 1.94, respectively. The mean ratios of concentrations in gingiva/serum, dental follicle/serum, and mandibular bone/serum were 1.58 ± 0.53, 1.54 ± 0.50, and 0.59 ± 0.35, respectively. The mean LVFX concentrations in gingival tissue, dental follicles and mandibular bone exceeded the MIC for 90% of clinically isolated oral strains of streptococci and most of the anaerobic bacteria. These results indicated that LVFX penetrated well into oral and maxillofacial tissue and that LVFX 500 mg q.d. treatment was as effective as, or more effective than, 100 mg t.i.d. for the clinical treatment of oral infections.

Burkitt's lymphoma is a malignant lymphoma of high malignancy grade and accounts for less than 1% of all cases of malignant lymphoma. Patients with malignant lymphoma in the oral and maxillofacial region including Burkitt's lymphoma, frequently present with gingival swelling, or a tumor mass/ulcers as the initial symptoms. We present an extremely rare case with bilateral mental nerve paralysis as the initial symptom without not only regional tumor but also brain and nose-pharyngeal area. This report indicates that the unexplained oral abnormalities such as inferior alveolar nerve hypoesthesia must be considered, potentially prodromal symptoms of Burkitt's lymphoma. © 2010 Asian Association of Oral and Maxillofacial Surgeons.

In this study, we investigated the use of perforated sheet platforms to improve the attachment of percutaneous devices to surrounding tissues. The model platform was created by a poly(methyl methacrylate) (PMMA) sheet with a matrix of 200-μm diameter perforations covering the groove (width, 3 mm; depth, 0.5 mm) prepared on the PMMA cylinder (diameter, 10 mm; length, 6 mm). Velour cuffs from peritoneal dialysis catheters were used as controls. Specimens were implanted percutaneously in rats, harvested with the surrounding tissues at 4 weeks after surgery, and subjected to mechanical tests and histological observations. The attachment strength of the experimental specimens to tissue was 138.4 ± 123.6 kPa (n = 5, mean ± SD); although it was greater than the 67.23 ± 45.78 kPa (n = 5) of the controls, no statistical significance was found. Histological observations of the experimental specimens revealed the collagen fibers originating from the surrounding tissues, passing through the perforations of the sheet, merging into the collagen fibers running behind the sheet, and thus anchoring the tissues to the device. In contrast, such anchoring of collagen fibers was not evident in the controls. These results suggest that the proposed perforated sheet structures are effective for soft tissue attachment. Copyright © American Society of Artificial Internal Organs.

Aim: To evaluate the conservativeness of low dose rate interstitial irradiation (LII) for cancer of the mobile tongue. Patients and Methods: Between 1975 and 2002, 100 consecutive patients (71 men, 29 women) underwent LII as curative treatment. Stages were I/II/III/IV= 16/63/16/4. Seventy-one cases were treated with LII alone and 29 cases treated combined with external irradiation. Median total dose of LII was 70 Gy 17 days. Results: Overall, 5- and 10-year local control and LII-treated patients' survival rates were 93% and 91%, 64% and 57%, respectively. Delayed neck metastases were observed in 21% of initially N0 cases, 56% of which could be salvaged by operation. Early stage and well-differentiated tumors carried better prognoses. Conclusion: LII of cancers of the mobile tongue results in good local control and survival. With careful monitoring of patients to ensure early detection of delayed metastases, LII should allow organ conservation and yield favourable therapeutic results compared with those of surgery.