Biomechanical evaluation on bone regeneration in mandibular distraction osteogenesis combined with compression stimulation

The purpose of this study was to investigate the clinical, biomechanical, and histologic changes in new distraction osteogenesis (DO) technique combined with a compression stimulation in accordance to different compression-distraction force ratio. 23 adult male rabbits underwent open-osteotomy at the mandibular body area and a external distraction device was applied. In the control group of 8 rabbits, only a 8 mm of distraction was performed by conventional DO technique. In an experimental group of 15 rabbits, a distraction followed by a compression force was performed according to the ratio of compression-distraction suggested by authors. The rate of experimental group I was set up as a 2 mm compression versus 10 mm distraction and the rate of experimental group II was set up as a 3 mm compression versus 11 mm distraction. All the rabbits were sacrificed for a gross finding, biomechanical, histomorphometric and histologic findings at the time of 55 days from the operation day. The results were as follows: 1. On the gross findings, because all rabbits had a sufficient healing time, every distracted new bone had good bone quality and we could not find any difference among all three groups. 2. In the histologic findings, rapid bone maturation (wide lamellar bone formation in the cancellous and cortical bone areas) was observed in two experimental groups compared to the control group. 3. On the bone density tests, the experimental group II showed higher bone density than the other experimental group and control group (control group - 0,2906 g/cm2, experimental group I - 0.2961 g/cm2, experimental group II - 0.3328 g/cm2). 4. On the biomechanical tests, the experimental group II had significantly higher bone microhardness than the other experimental group and control group (control group - 252.7 MPa, experimental group I - 263.5 MPa, experimental group II - 426.0 MPa). 5. On the microhardness tests, when we compared the hardness ratio of distracted bone versus normal bone, we could find experimental group II had significantly higher hardness ratio than the other experimental group and control group (control group - 0.47, experimental group I - 0.575, experimental group II - 0.80). From this study, we could deduce that the modified distraction osteogenesis method with a compression stimulation might improve the quality of bone regeneration and shorten the consolidation period in comparison with conventional distraction osteogenesis techniques.

Initial Experience of Radiofrequency Ablation of Renal Tumor / 대한비뇨기과학회지

PURPOSE: We wanted to report the our early experience with performing nephron-sparing radiofrequency ablation (RFA) of renal tumor. MATERIALS AND METHODS: Three percutaneous RFAs were performed under combined computed tomography (CT) and ultrasonogram guided, and two intraoperative ultrasonograpy-guided laparoscopic RFAs were performed since June 2004. The treatment indications were localized, small (<4cm), solid renal masses in elderly patients and also the same type masses in the patients with comorbid conditions. The follow-up studies included physical examination, CBC, serum creatinine, urine analysis and kidney CT, and these were performed at day 1, 1 week, 1 month, 3 months, 6 months and 1 year after ablation, and then semi-annually thereafter. The mean follow-up duration was 8.8 months (range: 5-12 months). RESULTS: All five patients underwent successful RFA without any serious events. One patient had a mild perinephric hematoma and another patients had mild gross hematuria postoperatively. With a mean follow-up of 8.8 months, none of the patients showed any residual tumor on follow-up contrast-enhanced CT after the final tumor ablation. Complete tumor ablation was achieved after a single treatment session in 80% of the patients and in 20% of patients after the subsequent ablation sessions. CONCLUSIONS: Percutaneous or laparoscopic RFA is a promising nephron-sparing treatment for selected patients with small renal mass. Contrast-enhanced CT performed immediately after ablation is a reliable method to exclude residual viable tumor. The ultimate role for this modality will continue to evolve and this warrants further studies.

Mandibular distraction osteogenesis with compression force: Bone density, histological findings and TMJ response

The Initial Experience of Laparoscopic Ureteroureterostomy for Retrocaval Ureter / 대한비뇨기과학회지

Retrocaval ureter is a rare congenital anomaly that causes symptomatic hydronephrosis. Despite difficulties in the intracorporeal suturing, a retrocaval ureter is thought to be a good candidate for laparoscopic surgery, especially from the cosmesis. Laparoscopic ureteroureterostomy has advantages compared to conventional open surgery in terms of less pain, decreased blood loss, smaller operative wound and shorter hospital stay. Herein, we report our initial experience of laparoscopic ureteroureterostomy in a patient with a retrocaval ureter.

Novel Surgical Technique for Orthotopic Testicular Transplantation in Rats / 대한남성과학회지

PURPOSE: This study was performed to evaluate the functional and histological changes following orthotopic testicular transplantation. A new microsurgical technique was used for the transplantation. MATERIALS AND METHODS: Recipient rats were castrated, and microsurgically-removed testes from adult rats were utilized for orthotopic transplantation. Animals were divided into three groups:(1) the control group(n=6);(2) the castrated group(n=6);(3) the orthotopic testis transplantation group (n=12). In order to identify the survival of the testis after transplantation, testicular scans and histopathological examinations were performed. RESULTS: The following results were obtained from examination of transplanted testes: 1. Histopathologic findings. Excluding 2 transplanted rats which demonstrated ischemic necrosis, the testes of the other 10 transplantated rats showed almost normal histologic findings. 2. Testicular scan. Testicular scan was effective to differentiate the successfully transplanted testes from the testes with ischemic necrosis. CONCLUSIONS: These results demonstrate that orthotopic transplantation has a higher possibility of graft survival, and testicular scan is aneffective method to confirm the survival of transplanted testes. In addition, newly-developed orthotopic transplantation animal models could be used for research on the hypothalamus-pituitary-testis axis. The orthotopic transplantation technique could alsobe used as a new therapeutic method for congenital and acquired hypogonadism patients.

The Clinical Study on Parotid Gland Tumor

Tumors of the parotid gland are the most frequently encountered salivary gland tumors. Knowledge of the histology and anatomy of the salivary gland is important when considering the histiogenesis of salivary gland tumors, requiring close cooperation between the pathologist and the surgeon. Most tumors are benign epithelial formations. Pleomorphic adenomas predominate. Superficial lobectomy is adequate treatment. When the tumor involves a deep lobe, total parotidectomy is indicated. Treatment of malignant tumors depends on the histology, its TNM stage and other factors. Total parotidectomy with lymph adectomy and radiotherapy are needed in case of high grade malignancy. In children, vascular neoplasias are the most frequent, followed by malignant tumors. Their histological features and treatment are the same as for adults. We reviewed 64 cases of the parotid tumors at Department of surgery, Dong-A University Hospital from July. 1990 to Jan. 1999 for the purpose of apprehension of parotid gland tumor by the clinical study and review. Over all sex ratio was 1: 1.13 (M: F), mean age was 38.9 years, mean size was 3.53cm. According to histologic findings of 64 cases, pleomorphic adenoma was 55 (85.9%), Warthin's tumor was 3 (4.7%), mucoepidermoid carcinoma was 3 (4.7%), squamous cell carcinoma was 2 (3.1%), acinic cell carcinoma was 1 (1,6%). Post op. facial nerve palsy 16 (25%), Frey's syndrome 11 (17.2%) cases were happened. Hence, the clinical manifestation of pain, tenderness, facial N. palsy suggest malignant tumors.

Reduction malarplasty with bone ostectomy & repositioning only using intraoral approach