• Maxillofacial Plastic and Reconstructive Surgery
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• v.16 no.4
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• pp.428-437
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• 1994

Optic nerve injury serious enough to result in blindness had been reported to occur in 3% of facial fractures. When blindness is immediate and complete, the prognosis for even partial recovery is poor. Progressive or incomplete visual loss may be ameliorated either by large dosage of steroid or by emergency optic nerve decompression, depending on the mechanism of injury, the degree of trauma to the optic canal, and the period of time that elapses between injury and medical intervention. We often miss initial assessment of visual function in management of facial fracture patients due to loss of consciousness, periorbital swelling and emergency situations. Delayed treatment of injuried optic nerve cause permanent blindness due to irreversible change of optic nerve. But by treating posttraumatic optic nerve injuries aggressively, usable vision can preserved in a number of patients. The following report concerns three who suffered visual loss due to optic nerve injury with no improvement after steroid therapy and/or optic nerve decompression surgery.

• Journal of Korean Foot and Ankle Society
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• v.12 no.2
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• pp.128-134
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• 2008

Purpose: We evaluated the complications and failures after total ankle arthroplasty during at least 2 years short term follow up. Materials and Methods: There were 45 cases of 42 patients of HINTEGRA$^{{R}}$ (Newdeal SA, Lyon, France) model from November 2004 to August 2006. Follow up averaged at least 2 year. We evaluated the complications and analyzed the cause of the failures. Results: There were totally 15 cases of complication, 5 cases of medial impingement syndrome, 3 cases of varus malposition, 2 cases of delayed healing of wounds, and each one case of deep peroneal nerve problem, medial malleolus fracture, post-operative deep infection, gouty arthritis pain, and Achilles tendinitis. Conclusion: Total ankle arthroplasty had higher complication rate than any other joint arthroplasty, so we need a more meticulous preoperative and peri-operative care.

• Journal of Advanced Marine Engineering and Technology
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• v.26 no.1
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• pp.76-82
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• 2002

In this study, the rotary bending fatigue test was carried out with low carbon steel(SM25C). The specimens were heat-treated in order to change the grain size, and investigated items are fatigue limit, small crack initiation, fatigue crack propagation behavior and possibility of fatigue life prediction according to the different grain size. The summarized result are as follows ; Fatigue limit of the smooth specimen was dependent upon the grain size. The fatigue crack initiation of the small grain size specimen was delayed more than that of the large grain size specimen. And the small cracks of small grain size specimen were distributed in the narrow region of the main crack circumference contrary to the large grain size specimen. The main crack was grown along the grain boundary having co-alliance with small cracks. The experiment material has quantitatively disclosed the possibility of fatigue life prediction because the fatigue crack propagation behavior is dependent upon the grain size.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.192-192
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• 2008

As the lifetime of nuclear power plants (NPPs) reaches design life, the probability for fatal accidents increases. Most of accidents are known to be caused by degradation of mechanical components. Pressure tubes are the most important components in CANDU reactor. They are subjected to various aging mechanisms such as delayed hydride cracking (DHC), irradiation and corrosion, etc. Therefore, the integrity of pressure tube is key concern in CANDU reactor. Up to recently, conventional deterministic approaches have been utilized to evaluate the integrity of components. However, there are many uncertainties to prevent a rational evaluation. The objective of this paper is to assess the failure probability of pressure tube in CANDU. To do this, probability fracture mechanics (PFM) analysis based on the Genetic Algorithm (GA) is performed. For the verification of the analysis, a comparison of the PFM analysis using a commercial code and mathematical method is carried out.

• Journal of Korean Foot and Ankle Society
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• v.10 no.2
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• pp.207-212
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• 2006

Purpose: To evaluate the results of ankle lateral malleolar fractures classified as Danis-Weber type B accompanying osteoporosis that were treated with lag screw. Materials and Methods: 15 cases of Danis-Weber type B ankle lateral malleolar fractures that had T score of less than -2.5 in BMD(bone mineral density) test were selected from June 2003 to December 2005. 10 cases were males and 5 cases were females with mean age of 59 years. The main injury mechanism was supination and external rotation. Mean follow-up period was 16 months. Clinical and radiologic evaluation was done according to Meyer and Kumler's criteria. Results: All cases showed satisfying result and mean radiologic bone union period was 3 months. Anatomic reduction and bone union was acquired in all cases without complications including wound infection, skin necrosis, delayed union and nonunion Conclusions: Lag screw fixation seem to be excellent treatment of Danis-Weber type B lateral malleolar fractures with osteoporosis as it can minimize soft tissue injury and enable anatomic reduction with firm fixation.

• Journal of Energy Engineering
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• v.26 no.4
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• pp.1-6
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• 2017

This study evaluated hydrogen effect of metal and non-metallic materials used in the hydrogen blended natural gas vehicle. Hydrogen penetrated concentration of 34Cr-Mo steel(850MPa tensile strength) for winter driving conditions was measured 0.0018ppm and summer driving conditions was 5.3ppm. The critical hydrogen concentration of high strength metal used in this study was measured 1.03ppm by CLT. Therefore, 34CrMo steel cas cause problems in the 30% HCNG(25MPa) environment. In case of the test for non-metallic materials, all materials met the criteria of the gas resistance test, but Fluorocarbon Rubber material had a significant change in the volume. So if it is used, extra care is needed.

• Journal of Chest Surgery
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• v.53 no.4
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• pp.233-241
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• 2020

Vagal damage and subsequent pyloric denervation inevitably occur during esophagectomy, potentially leading to delayed gastric emptying (DGE). The choice of an optimal pyloric procedure to overcome DGE is important, as such procedures can lead to prolonged surgery, shortening of the conduit, disruption of the blood supply, and gastric dumping/bile reflux. This study investigated various pyloric methods and analyzed comparative studies in order to determine the optimal pyloric procedure. Surgical procedures for the pylorus include pyloromyotomy, pyloroplasty, or digital fracture. Botulinum toxin injection, endoscopic balloon dilatation, and erythromycin are non-surgical procedures. The scope, technique, and effects of these procedures are changing due to advances in minimally invasive surgery and postoperative interventions. Some comparative studies have shown that pyloric procedures are helpful for DGE, while others have argued that it is difficult to reach an objective conclusion because of the variety of definitions of DGE and evaluation methods. In conclusion, recent advances in interventional technology and minimally invasive surgery have led to questions regarding the practice of pyloric procedures. However, many clinicians still perform them and they are at least somewhat effective. To provide guidance on the optimal pyloric procedure, DGE should first be defined clearly, and a large-scale study with an objective evaluation method will then be required.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.2
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• pp.115-121
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• 2011

The size of hydrogen molecule is not so small as to invade into the lattice of material, and therefore, hydrogen invades into the material as atom. Hydrogen movement is done by diffusion or dislocation movement in the near crack tip or plastic deformation. Hydrogen appeared to have many effects on the mechanical properties of the Cr-Mo steel alloys. The materials for this study are 1.25Cr-0.5Mo and 2.25Cr-1Mo steels used at high temperature and pressure. The hydrogen amount obtained by theoretical calculation was almost same with the result solved by finite element analysis. The distribution of hydrogen concentration and average concentration was calculated for a flat specimen. Also, finite element analysis was employed to simulate the redistribution of hydrogen due to stress gradient. The calculation of hydrogen concentration diffused into the material by finite element method will provide the basis for the prediction of delayed fracture of notched specimen. The distribution of hydrogen concentration invaded into the smooth and notched specimen was obtained by finite element analysis. The hydrogen amount is much in smooth specimen and tends to concentrate in the vicinity of surface. Hydrogen embrittlement susceptibility of notched specimen after hydrogen charging is more remarkable than that of smooth specimen.

• Journal of Trauma and Injury
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• v.32 no.2
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• pp.71-79
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• 2019

Purpose: Recent developments in minimally invasive techniques have the potential to reduce surgical morbidity, promote patient recovery, accelerate surgical procedures, and thus improve cost-effectiveness in case management. In this study, we compared the treatment efficacy and results of supraorbital keyhole approach (SOKA) with those of conventional unilateral frontal craniotomy (CUFC) for traumatic intracerebral hemorrhage (TICH) in the frontal lobe. Methods: We analyzed the data of 38 patients who underwent CUFC (n=30) and SOKA (n=8) and retrospectively reviewed their medical records and radiological findings. Furthermore, we tried to identify the best surgical method for such lesions by including patients who underwent burr hole aspiration and drainage (BHAD) (n=9) under local anesthesia due to various circumstances. Results: The difference in the initial Glasgow coma scale score, operative time, and length of hospitalization between the CUFC and SOKA were statistically significant. All radiological features between the two groups including associated skull fracture, amount of pre- and postoperative hematoma, percentage of complete hematoma removal, pre- and postoperative midline shifting of the hematoma, and development of postoperative delayed hematoma were not statistically significant. Our experience of 46 patients with TICH in the frontal lobe with any of the three different surgical methods including BHAD enabled us to obtain valuable findings. Conclusions: Although it is difficult to insist that one particular approach is more useful than the other, we are confident that SOKA will have more advantages over CUFC in carefully selected patients with frontal TICH depending on the surgical experience of a neurosurgeon.

• Clinics in Shoulder and Elbow
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• v.25 no.2
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• pp.163-169
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• 2022

Distal humerus fractures (DHFs) are challenging to treat due to the locally complex osseous and soft tissue anatomy. Adequate exposure of the articular surface of the distal humerus is crucial when performing an anatomical reconstruction of the elbow. Even though "triceps-on" approaches are gaining popularity, one of the most commonly used surgical treatments for DHF is olecranon osteotomy. The incidence of complications related to this approach is unclear. This review was performed to assess the type and frequency of complications that occur with the olecranon osteotomy approach in the treatment of DHF. A literature search was conducted in the PubMed/Medline, Embase, and Cochrane Library digital databases up to February 2020. Only English articles describing complications of olecranon osteotomy in the treatment of DHF were included. Data on patient and surgical characteristics and complications were extracted. Statistical analysis was performed using SPSS. A total of 41 articles describing 1,700 osteotomies were included, and a total of 447 complications were reported. Of these 447 complications, wound infections occurred in 4.2% of osteotomies, of which 1.4% were deep infections and 2.8% were superficial. Problems related with union occurred in 3.7% of osteotomies, 2% of which represented non-union and 1.7% delayed union. The high risk of complications in olecranon osteotomy must be considered in the decision to perform this procedure in the treatment of DHF.