Koichi Takamori

Comparison of Material-Related Complications After Bilateral Sagittal Split Mandibular Setback Surgery: Biodegradable Versus Titanium Miniplates

PURPOSE The aim of the present prospective study was to compare material-related complications using biodegradable and titanium miniplates after bilateral sagittal split mandibular setback surgery. PATIENTS AND METHODS The subjects included 200 Japanese adults (67 men and 133 women, age range 18 to 45 years) with jaw deformities diagnosed as mandibular prognathism. All patients were prospectively and consecutively randomized to 2 study groups, receiving biodegradable or titanium fixation plates. Of the 200 patients, 110 underwent bilateral sagittal split ramus osteotomy with a biodegradable fixation plate and 90 underwent bilateral sagittal split ramus osteotomy with a titanium metal plate. The clinical records and radiologic findings of the patients were reviewed, and the incidence of material-related complications was compared. RESULTS The incidence of postoperative complications and breakage in the biodegradable group was 8.2% (9 cases) and in the titanium group was 3.3% (3 cases). No statistically significant difference in the incidence of complications was found between the 2 groups. Fractures of the biodegradable plate occurred at a significantly greater frequency in patients with asymmetry than in patients without asymmetry. CONCLUSION Biodegradable plates were reliable with minimal material-related complications. However, the use of biodegradable plates should be recommended for minimally loaded situations.

Risk factors for breakage of biodegradable plate systems after bilateral sagittal split mandibular setback surgery.

The aim of this retrospective study was to evaluate the risk factors associated with breakage of biodegradable plate systems after bilateral sagittal split mandibular setback. We studied 169 Japanese adults (62 men, 107 women; age range 16-53 years) with deformities of the jaw diagnosed as mandibular prognathism. All patients were treated by bilateral sagittal split osteotomy (BSSO) with 2 biodegradable fixation plates and screws at the anterior mandibular ramus. We collected the following data from the medical records and radiological findings: sex; age; degree of setback; presence of asymmetry; presence of open bite; operation; design of the plate; operating time; and blood loss. Multiple logistic regression analysis was used to find the factors that were independently associated with the dependent variable: breakage of the biodegradable plate system. In 10 of the 169 patients (6%) the biodegradable plate system for the BSSO broke. Factors that influenced whether or not the biodegradable plate system fractured were if they were asymmetrical (odds ratio (OR) 5.35; P=0.02) and had an open bite (OR 5.20; P=0.02). Asymmetry or open bite was significantly associated with breaks in the biodegradable plate system. Biodegradable plates should be used only when loading is minimal.

Preoperative Ultrasound Assessment of Tumour Thickness in Tongue Carcinomas

Objective: To evaluate the clinical usefulness of intraoral ultrasonography compared with computed tomography and magnetic resonance imaging to assess tumour thickness in patients with carcinoma of the tongue. Patients and Methods: Twenty eight patients with squamous cell carcinoma of the tongue who were treated by tumour resection with or without neck dissection and/or preoperative adjunctive therapy, were reviewed. Tumour thickness was assessed preoperatively by ultrasonography, computed tomography, or magnetic resonance imaging and the findings were compared with postoperative measurements and histological grading obtained from histological sections of tongue resection specimens. Results: The ultrasound findings were of moderately well-defined sonolucent lesions. The intraoral ultrasound depth correlated with tumour stage, tumour size, nodal status, mode of invasion (Y-K classification), muscular invasion, and invasive front grading. Ultrasound depth did not correlate with growth type, differentiation, or Anneroths malignancy. The mean intraoral ultrasound depth was 10.5 mm (SD, 8.1 mm) and the mean tumour depth assessed by histological sections was 7.1 mm (SD, 6.3 mm). There was a significant correlation between the ultrasound depth and the tumour depth by histological section (r = 0.976; p < 0.0001). Measurements by computed tomography and magnetic resonance imaging also correlated with tumour depth by histological section (r = 0.823; p = 0.0018, and r = 0.778; p < 0.0001, respectively). Conclusion: These findings suggest that ultrasonography is a reliable method for the preoperative assessment of tumour thickness in tongue carcinoma.

Epidermal choristoma arising on the midline gingiva as a congenital epulis: A case report

We report an extremely rare case of epidermal choristoma in the midline of the maxillary gingiva. A 2-month-old Japanese boy presented with a polypoid mass in the midline of the maxillary gingiva. The initial clinical diagnosis was congenital epulis. Microscopic examination revealed a granular cell layer and melanin pigmentation within the basal cell layer. Furthermore, sebaceous glands and hair follicles were observed within the connective tissue. The histological diagnosis was therefore epidermal choristoma, based on clinical microscopic observations.

Oral tonsil in the floor of mouth : Ectopic oral tonsillar tissue simulating benign neoplasms

Abstract Oral tonsils, ectopic sublingual tonsillar tissue, manifest as an asymptomatic, nonulcerated, freely movable nodule. We present a case of a 28-year-old female with ectopic tonsillar tissue in the anterior floor of the mouth. The lesion was totally removed under local anesthesia. The microscopic examination showed well demarcated and encapsulated lymphoid tissue with lymphoid follicles and central lacuna-like squamous epithelium covering space. These findings are similar to tonsillar tissue, and the case was finally diagnosed as sublingual oral tonsil. This article underlines that oral tonsils occur more frequently than is generally recognized, and the importance of differential diagnosis of soft tissue nodules in the oral floor.

Predictive Markers for Late Cervical Lymph Node Metastasis in Patients with N0 Squamous Cell Carcinoma of the Tongue

Abstract Objective: To find useful markers for predicting late cervical metastasis in patients with N0 squamous cell carcinoma of the tongue. Materials and Methods: The clinicopathological features of 57 consecutive patients with previously untreated N0 squamous cell carcinoma of the tongue were reviewed. Thirty patients had T1 disease, 20 had T2 disease, and 7 had T3 disease. All patients were treated with partial glossectomy without elective neck dissection. Clinicopathological factors were analysed to determine the factors predicting late cervical lymph node metastasis. Results: The overall cervical lymph node metastasis rate was 19.3%. The clinicopathologic factors significantly associated with the development of cervical lymph node metastasis were tumour size (30 mm), tumour depth (4 mm), differentiation (moderate), mode of invasion (G4C 4D), microvascular invasion (present), muscle invasion (present), and invasive front grading (12 points). In a multivariate logistic regression analysis, invasive front grading ≥12 points in squamous cell carcinoma of the tongue with a tumour depth ≥4 mm had predictive value for late cervical lymph node metastasis. Conclusion: The results indicate that patients with N0 invasive tongue carcinoma with a tumour depth ≥4 mm or invasive front grading ≥12 points should be considered at high risk for late cervical lymph node metastasis. These factors should be considered in the decision to electively treat the neck.

A case of pilomatrixoma in the cheek in a 7-year-old girl

a b s t r a c t Pilomatrixoma, also known as a calcifying epithelioma, is a benign tumor originating from a hair follicle. We present a case of pilomatrixoma in a 7-year-old girl complaining of swelling in the cheek. Clinical examination disclosed a mass 10 mm in diameter and it was totally removed. The microscopic examination showed encapsulated tumors mainly composed of eosinophilic ghost cells and partly with basophilic portions in hyalinized fibrous stroma with calcification. Preoperative ultrasound and magnetic resonance imaging gave us useful information for complete tumor excision that the tumor existed just under the skin and the risk of facial palsy would be relatively low.