• Tuberculosis and Respiratory Diseases
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• v.86 no.3
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• pp.203-215
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• 2023

Background: Surgical resection is the standard treatment for early-stage lung cancer. Since postoperative lung function is related to mortality, predicted postoperative lung function is used to determine the treatment modality. The aim of this study was to evaluate the predictive performance of linear regression and machine learning models. Methods: We extracted data from the Clinical Data Warehouse and developed three sets: set I, the linear regression model; set II, machine learning models omitting the missing data: and set III, machine learning models imputing the missing data. Six machine learning models, the least absolute shrinkage and selection operator (LASSO), Ridge regression, ElasticNet, Random Forest, eXtreme gradient boosting (XGBoost), and the light gradient boosting machine (LightGBM) were implemented. The forced expiratory volume in 1 second measured 6 months after surgery was defined as the outcome. Five-fold cross-validation was performed for hyperparameter tuning of the machine learning models. The dataset was split into training and test datasets at a 70:30 ratio. Implementation was done after dataset splitting in set III. Predictive performance was evaluated by R² and mean squared error (MSE) in the three sets. Results: A total of 1,487 patients were included in sets I and III and 896 patients were included in set II. In set I, the R² value was 0.27 and in set II, LightGBM was the best model with the highest R² value of 0.5 and the lowest MSE of 154.95. In set III, LightGBM was the best model with the highest R² value of 0.56 and the lowest MSE of 174.07. Conclusion: The LightGBM model showed the best performance in predicting postoperative lung function.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.1
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• pp.65-68
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• 2004

CyberKnife is a stereotactic radiosurgery system which could be used to treat many tumors and lesions. It provides the surgeon unparalleled flexibility in targeting using a compact light linear accelerator mounted on a robotic arm. Advanced image guidance technology tracks patient and target position during treatment, ensuring accuracy without the use of an invasive head frame. CyberKnife with Dynamic Tracking Software is cleared to provide radiosurgery for lesions anywhere in the body when radiation treatment is indicated. It has often been used to radiosurgically treat otherwise untreatable tumors and malformations. Moreover, this instrument treats tumors at body sites, most of which are unreachable by other stereotactic systems. Compared with conventional radiotherapy, it is fundamentally different that using non-invasive, frameless, no excessive radiation exposure to normal tissue. In oral malignant neoplasm, surgical excision and radiation therapy should be tried first, additionally chemotherapy could be considered. However, after failure of conventional therapies, patients had poor systemic condition and surgical limitation. So, CyberKnife could be a suitable therapy. A 49 years man was referred in recurred mandibular cancer treated by radiotherapy. The tumor was considered inoperable, because of extensive invasion and was not expected to good response to conventional therapies. We experienced a case of CyberKnife after 4 cycle chemotherapies, so we report it with review of literature.

• Journal of Chest Surgery
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• v.50 no.1
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• pp.1-7
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• 2017

Complex lesions of the thoracic aorta are traditionally treated in 2 surgical steps with the elephant trunk technique. A relatively new approach is the frozen elephant trunk (FET) technique, which potentially allows combined lesions of the thoracic aorta to be treated in a 1-stage procedure combining endovascular treatment with conventional surgery using a hybrid prosthesis. These are very complex and time-consuming operations, and good results can be obtained only if appropriate strategies for myocardial, cerebral, and visceral protection are adopted. However, the FET technique is associated with a non-negligible incidence of spinal cord injury, due to the extensive coverage of the descending aorta with the excessive sacrifice of intercostal arteries. The indications for the FET technique include chronic thoracic aortic dissection, acute or chronic type B dissection when endovascular treatment is contraindicated, chronic aneurysm of the thoracic aorta, and chronic aneurysm of the distal arch. The F ET technique is also indicated in acute type A aortic dissection, especially when the tear is localized in the aortic arch; in cases of distal malperfusion; and in young patients. In light of the great interest in the FET technique, the Vascular Domain of the European Association for cardio-thoracic Surgery published a position paper reporting the current knowledge and the state of the art of the FET technique. Herein, we describe the surgical techniques involved in the FET technique and we report our experience with the F ET technique for the treatment of complex aortic disease of the thoracic aorta.

• Journal of Oral Medicine and Pain
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• v.19 no.1
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• pp.33-43
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• 1994

The purpose of this paper was to observe the influence of Ga-As semiconductor-low power generating laser on she appearance and actions of tenascin, extracellular matrix, as healing process of intentional wound on the experimental animals is taking place. 35 rabbits were divided into control and experimental group. ; and on each, 3mm-long and 2mm-deep, surgical wounds were created on buccal oral mucosa and thoracodorsal portion of skin. Ga-As laser was applied to the experimental group starting a day of the day the wounds were created , the laser was applied for 5 minutes every other day. Tissue samples were taken after the 2, 4, 7, 10, and 14 days after wound formation. Then tile healing process of experimental and control groups were observed and compared, using light microscope. Afterwards, the samples were immunohistochemical stained and again observed tenascin by quantitative measuring. The following results were obtained : 1. Tenascin was observed prevalently on epithelial cells, border area of dermis, and interstitial matrix between connective tissue layers in both experimental and control groups. 2. In oral mucosa, the experimental group showed significant increase in the appearance of tenascin after 4 days compared to the control group, but after 10 days, it decreased to a point which is even less than the control group. 3. In the skin samples, the pattern of appearance of tenascin was the same in both groups, but there was some difference concerning when the peak period was shown, In the experimental group, the peak period of tenascin expression was the 7 days after wound formation in epithelium and connective tissue. In the control group, the peak period was 10 days after. 4. In both the experimental and control groups, tenascin first appeared in the epithelium near the wound area and submucosa, and then spread on the underlying connective tissue. In conclusion, appearance of tenascin is closely related to regeneration of epithelium and development of granulation tissue : therefore, low power laser, which fastnes appearance of tenascin, is sure to faciltate healing process of oral mucosa.

• Journal of Korean Foot and Ankle Society
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• v.27 no.4
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• pp.148-153
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• 2023

Traditionally, arthroscopic microfracture and autologous osteochondral autograft transplantation have been the primary surgical treatments for osteochondral lesions of the talus. On the other hand, recent advancements have introduced alternative approaches, such as autologous chondrocyte transplantation, matrix-derived autologous chondrocyte transplantation, intra-articular injection of concentrated bone marrow aspirate concentrate, and the use of fibrin glue to address chondral defects. Furthermore, some studies have explored a combination of bone marrow aspirate and matrix-derived chondrogenesis. In light of these developments, this report presents a case study of a young male patient in his early twenties with a relatively large osteochondral lesion exceeding 1.5 cm² on the medial talar dome. Instead of removing the osteochondral lesion, a surgical approach was employed to retain the lesion while addressing the unstable cartilage in the affected area. This approach involved a combination of bone marrow aspirate concentrate and matrix-derived chondrogenesis. The treatment yielded favorable clinical outcomes and ultimately successfully induced the bony union of osteochondral lesions. This paper reports the author's experience with this innovative approach with a review of the relevant literature.

• Journal of Periodontal and Implant Science
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• v.41 no.6
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• pp.302-308
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• 2011

Purpose: The emergence profile concept of an implant restoration is one of the most important factors for the esthetics and health of peri-implant soft tissue. This paper reports on two cases of gingival recontouring by the fabrication of a provisional implant restoration to produce an optimal emergence profile of a definitive implant restoration. Methods: After the second surgery, a preliminary impression was taken to make a soft tissue working cast. A provisional crown was fabricated on the model. The soft tissue around the implant fixture on the model was trimmed with a laboratory scalpel to produce the scalloped gingival form. Light curing composite resin was added to fill the space between the provisional crown base and trimmed gingiva. After 4 to 6 weeks, the final impression was taken to make a definitive implant restoration, where the soft tissue and tooth form were in harmony with the adjacent tooth. Results: At the first insertion of the provisional restoration, gum bleaching revealed gingival pressure. Four to six weeks after placing the provisional restoration, the gum reformed with harmony between the peri-implant gingiva and adjacent dentition. Conclusions: Gingival recontouring with a provisional implant restoration is a non-surgical and non-procedure-sensitive method. The implant restoration with the optimal emergence profile is expected to provide superior esthetic and functional results.

• The korean journal of orthodontics
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• v.32 no.4 s.93
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• pp.257-264
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• 2002

If dental ankylosis occurs in maxillary incisors of a growing child, the ankylosed tooth can not move vertically with the subsequent disturbance in vertical growth of the alveolar process. Because ankylosed tooth does not respond orthodontic force, extraction was recommended in the past. But the loss of tooth and accompaning alveolar bone loss incur compromised esthetic situation. And it is very hard to replace by prosthetics. So intentional surgical luxation and orthodontic movement was attempted, but usually this approach is followed by recurrence of the ankylosis. Nowadays the unitooth subapical osteotomy and rapid movement of block bone was reported. Two cases we presented, one is treated by intentional luxation and the other is by unitooth subapical osteotomy following application of light continuous force soon.

• Journal of Chest Surgery
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• v.35 no.8
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• pp.634-637
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• 2002

Thymic carcinoid or neuroendocrine tumor of thymus is a very rare disease and has poor prognosis due to frequent recurrence and distant metastasis. A 43-year-old man was refered to our hospital because of Rt. chest pain and tightness. Chest X-ray revealed $7{\times}8$cm sized mass on Rt. anterior mediastinum. Surgical excision was performed and light microscopic, immunohistochemical and electron microscopic findings were confirmed as atypical thymic carcinoid tumor with thymic cyst. The patient has been followed up without recurrence or distant metastasis postoperatively for 3 months to now. We report a case of atypical thymic carcinoid with thymic cysts.

• Archives of Plastic Surgery
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• v.39 no.2
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• pp.158-161
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• 2012

Myopericytoma is a benign tumor that is composed of myoid-appearing oval to spindle-shaped cells with a concentric perivascular pattern of growth. The tumor is morphologically heterogeneous and can exhibit a broad histologic spectrum. We describe a case of multiple myopericytoma occurring in the head and neck skin region with involvement of the parotid gland where it is known to occur very rarely. A 40-year-old woman noticed multiple enlarging, painless, round-shaped masses on her left cheek. The patient had experienced a similar lesion of the same area 8 years earlier which was completely excised and the pathological diagnosis was spindle cell type myoepithelioma. On a computed tomographic image, one mass involved the superficial parotid gland and was well encapsulated. Excision of the facial masses and superficial parotidectomy with facial nerve preservation were performed. A diagnosis of myopericytoma was established in light of the immunohistochemical pattern with the histopathological findings. Over the 4-year follow-up period, there was no evidence of recurrence. As many perivascular myoid neoplasms share common morphologic features with myopericytoma, we should consider the differential diagnosis, and confirm the histological findings with appropriate immunohistochemical staining. After identifying myopericytoma, it should be treated with wide surgical excision to prevent local recurrence.

• Journal of Chest Surgery
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• v.31 no.3
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• pp.319-323
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• 1998

Thymic carcinoid tumor is a rare mediastinal tumor, which was firstly described by Rosai and Higa in 1972. A carcinoid tumor of the thymus has recently been regarded as a distinct tumor from thymoma, and is probably Kultschizky cell origin. The pathologic diagnosis of thymic carcinoid is made from findings from light microscopy, immunohistochemical studies and electron microscopy. About 50% of thymic carcinoids were seen with endocrinopathies. Recurrences and extrathoracic metastasis are characteristics of thymic carcinoids. Surgical removal of the intial and tumor recurred are considered to be the most effective treatment today. However, the role of the adjuvant radiotherapy and the chemotherapy is still uncertain. Herein we report a case of thymic carcinoid tumor, which was confirmed by operation and pathologic study.