• Maxillofacial Plastic and Reconstructive Surgery
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• v.36 no.1
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• pp.30-36
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• 2014

There are many treatment options in management of mandibular condylar neck fractures. Closed reduction is the most conservative treatment; however, achievement of anatomic reduction is difficult, and there are some risks of mandibular functional impairment. Open anatomic reduction and internal fixation have some advantages; therefore, many oral and maxillofacial surgeons have attempted to achieve anatomic reduction through the open approach and extracorporeal reduction and fixation. However, when using this method, there is some risk of resorption of the fractured mandibular condylar head. Therefore, we designed a modified extracorporeal reduction technique, without detaching the lateral pterygoid muscle in order to maintain the blood supply to the fractured mandibular condylar head. We believe that this minor modification may minimize the risk of resorption of the fractured mandibular condylar head. In this article, we introduce this technique in detail, and report on two cases.

• Journal of Korean Foot and Ankle Society
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• v.1 no.1
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• pp.51-58
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• 1997

The purpose of this study is to evalute the efficacy af the Ilizarov external fixation for the surgical treatment. of the tibial plafond fractures. We reviewed retrospectively fourteen cases of tibial plafond fractures with moderate to severe soft. tissue damage, which were fixed with Ilizarov external fixator. Using the AO Muler classification, there were four Type C1 fractures, six Type C2 and four Type C3. In most, of the cases, the ankles were operated on with other associated fractures within a few days after injury. We reduced the fracture indirectly by soft issue taxis and fixed externally across the ankle joint. using the circular external fixator with tensioned wires and ankle hinge. In cases of inadequate closed reduction, we applied limited open reduction and internal fixation. Range of motion exercise began immediately. Postoperative follow-up averaged fourteen months (ranges, 8-30 months). Overall clinical results rated good or excellent in 7 cases, fair in 4 and poor in 3. There were three cases of pin tract infection which were resolved with short-term antibiotics and local care; one delayed wound closure in a patient. whose fracture was associated with Type III open wound; one wound slough in a patient associated with Type II open wound, which was closed later by skin graft; and one osteoarthritis. From this review, we concluded that cross-ankle circular external fixation with tensioned wires with or without. limited open reduction is a reasonable alternative for the treatment of the tibial plafond fractures with severe soft tissue damage.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.16 no.4
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• pp.419-427
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• 1994

Because of the prominence of the nose and its central location, it is the most frequently encountered fractures in the face. Yet reports about the nasal bone fractures are virtually rare in the oral and maxillofacial surgical literatures. This is a retrospective study on 19 nasal bone fractures treated in Chosun university hospital Department of Oral & Maxillofacial Surgery from Jan. 1991 to Sep. 1993, under admission to our Dept. and the obtained results were as follows. 1. Of the 240 patients with facial bone fractures, 28 patients suffered nasal fractures(12%) and male to female ratio was 5.3:1. 2. The most frequent cause was traffic accidents(39%)m, the next fall down(36%), first blow(4%). 3. The age frequency was the highest in the fifth decade (32%). 4. Clinical classification of nasal fractures was simple fractures(74%), combined fractures(26%), and single fractures(37%), combined fractures(63%). 5. The most frequently combined site was maxilla(50%). 6. Treatments of nasal fractures were closed reduction(63%), open reduction(5%), and secondary rhinoplasty(32%). 7. The initial treatment time from accident was 1.7 days in single fractures, and 3.5 days in combined fractures, and the period of splint retained was about 8.2 days in single fracture, about 8.7 in combined fracture. 8. It was necessary to treat secondarily in delayed treatment, and all treatment methods showed relatively good prognosis. 9. Closed reduction was treated under local anesthesia, but open reduction & secondary rhinoplasty was treated under general anesthesia except 1 case. 10. The complications were disturbance of swellings 5 cases, ethetic problem 5 cases, epiphora 3 cases, abnormal sensation 6 cases in relation with other fractures.

• Archives of Craniofacial Surgery
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• v.18 no.1
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• pp.30-36
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• 2017

Background: Nasal fractures have a tendency of resulting in structural or functional complications, and the results can vary according to the type of nasal bone fracture. The aim of this study was to evaluate the objective postoperative results according to the type of nasal bone fractures. Methods: We reviewed 313 patients who had a closed reduction of nasal bone fracture. The classification of nasal bone fracture by Stranc and Robertson was used to characterize the fracture type: frontal impact group type I (FI), frontal impact group type II (FII), lateral impact group type I (LI), lateral impact group type II (LII), and comminuted fracture group (C). For each patient, we tried to use the same axial image section of computed tomographic (CT) scans before and immediately after operation. Postoperative outcomes were classified into 4 grades: excellent (E), good (G), fair (F), and poor (P). We also analyzed postoperative complications by fracture type. Results: Regarding the postoperative CT images, 189 subjects showed E results, 99 subjects showed G, 18 subjects showed F, and 7 subjects showed P reduction. The rate of operation results graded as E by each fracture type was 66.67% in FI, 52.0% in FII, 64.21% in LI, 62.79% in LII, and 21.74% in C. Complications of FI (7.14%), LII (13.95%), and C (13.04%) groups occurred more than in the FII (4.00%) and LI (4.21%) groups. Conclusion: It seems that the operation result by fracture type was better in the FI, LI, and LII type than the FII and C type; after one month, however, LII type showed more complications than other types. The septal fracture can be thought to affect early reduction results in nasal bone fractures.

• Journal of IKEEE
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• v.5 no.1 s.8
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• pp.16-23
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• 2001

Passive noise reduction is a classical approach to attenuate industrial noise, and an active noise cancellation has several advantages over the passive noise cancellation. The active noise reduction system offers a better low frequency performance with a smaller and lighter system. This paper presents a simple active closed loop control system which consists of an controller for inverting and compensating the phase delay, a microphone for picking up the external noise, and a loudspeaker for radiating the acoustic out of phase signal to reduce the external noise, and external noise can be reduced after compensating the phase difference to be $180^{\circ}$ in the frequency of maximum value in the amplitude response. The noise of the phase delay covered from $50^{\circ}\;to\;310^{\circ}$ tends to be reduced in the active noise control system and it is possible to obtain a noise cancelling of up to approximately 20[dB] at the ears in the enclosurer.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.247-249
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• 2009

This paper investigates active noise control(ANC) of a rectangular cavity using single channel filtered-x least mean square(FXLMS) algorithms to reduce interior noise globally. To obtain global reduction of the interior noise, multichannel active control should be incorporated in general. We, however, examined firstly the optimal location of the secondary speaker that produces a global reduction of the interior noise field. We then investigated the frequency characteristics of the reduction to yield the effective frequency band of the active control system. It follows that the secondary speaker should be located as close to the primary source as possible in order to obtain global reduction.

• 대한족부족관절학회:학술대회논문집
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• 2009.04a
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• pp.8-8
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• 2009

• Proceedings of the Korea Water Resources Association Conference
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• 2005.09b
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• pp.982-983
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• 2005

• Wind and Structures
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• v.28 no.4
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• pp.255-270
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• 2019

Aerodynamic configurations of bridge decks have significant effects on the aerostatic torsional divergence and flutter forsuper long-span bridges, which are onset for selection of suitable bridge decksfor those bridges. Based on a cable-stayed bridge with double main spans of 1500 m, considering typical twin-box, stiffening truss and closed-box section, which are the most commonly used form of bridge decks and assumed that the rigidity of those section is completely equivalent, are utilized to investigate the effects of aerodynamic configurations of bridge decks on aerodynamic instability performance comprised of the aerostatic torsional divergence and flutter, by means of wind tunnel tests and numerical calculations, including three-dimensional (3D) multimode flutter analysis and nonlinear aerostatic analysis. Regarding the aerostatic torsional divergence, the results obtained in this study show twin-box section is the best, closed-box section the second-best, and the stiffening truss section the worst. Regarding the flutter, the flutter stability of the twin-box section is far better than that of the stiffening truss and closed-box section. Furthermore, wind-resistance design depends on the torsional divergence for the twin-box and stiffening truss section. However, there are obvious competitive relationships between the aerostatic torsional divergence and flutter for the closed-box section. Flutter occur before aerostatic instability at initial attack angle of $+3^{\circ}$ and $0^{\circ}$, while the aerostatic torsional divergence occur before flutter at initial attack angle of $-3^{\circ}$. The twin-box section is the best in terms of both aerostatic and flutter stability among those bridge decks. Then mechanisms of aerostatic torsional divergence are revealed by tracking the cable forces synchronous with deformation of the bridge decksin the instability process. It was also found that the onset wind velocities of these bridge decks are very similar at attack angle of $-3^{\circ}$. This indicatesthat a stable triangular structure made up of the cable planes, the tower, and the bridge deck greatly improves the aerostatic stability of the structure, while the aerodynamic effects associated with the aerodynamic configurations of the bridge decks have little effects on the aerostatic stability at initial attack angle of $-3^{\circ}$. In addition, instability patterns of the bridge depend on both the initial attack angles and aerodynamic configurations of the bridge decks. This study is helpful in determining bridge decksfor super long-span bridges in future.

• Archives of Plastic Surgery
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• v.36 no.6
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• pp.735-742
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• 2009

Purpose: The management of fractures of mandibular subcondyle continues to be controversial between open and closed treatment. The purpose of this article is to explain the endoscopic assisted open reduction and internal fixation and minimize the controversy. Methods: Nine patients of mandibular subcondylar fracture were reduced and fixed by using intraoral endoscopic - assisted open reduction and internal fixation and were followed up for 14 ~ 24 months after surgery. Results: Eight patients of mandibular subcondylar fracture had been treated without significant complications. One patient, whose malocclusion had been remained, was recovered normal occlusion by maxillomandibular fixation using intermaxillary screws for 3 weeks. Conclusion: The advantages of endoscopic - assisted open reduction and internal fixation are direct visualization, accurate fracture repair, minimized scar, decreased morbidity. And maxillomandibular fixation is not needed when it is done by accurate reduction and rigid fixation with one miniplate in the region of subcondylar fracture. With the above consideration, endoscopic - assisted open reduction and internal fixation can be considered as one of the best treament for subcondylar fracture of the mandible.