• Archives of Craniofacial Surgery
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• v.12 no.2
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• pp.116-120
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• 2011

Purpose: Scalp avulsion is a life-threatening injury that may cause trauma to the forehead, eyebrows, and periauricular tissue. It is difficult to treat scalp avulsion as it may lead to severe bleeding. Therefore, emergency scalp replantation surgery is necessary, and we must consider the function, aesthetics, and psychology of the patients. A case of scalp avulsion leading to massive bleeding was encountered by these authors, which led to a failure to achieve the proper operation conditions in an adequate time period. Methods: A 49-year-old female was hospitalized due to having had her head caught in a rotatory machine, causing complete scalp avulsion which included the dorsum of the nose, both eyebrows, and ears. Emergent microsurgical replantation was performed, where a superficial temporal artery and a vein were anastomosed, but the patient's vital signs were too unstable for further operation due to excessive blood loss. Three days after the microanastomosis, venous congestion developed at the replanted scalp, and a medicinal leech was used. Leech therapy resolved the venous congestion. A demarcation then developed between the vitalized scalp tissue and the necrotized area. Debridement was performed 2 times on the necrotized scalp area. Finally, split-thickness skin graft with a dermal acellular matrix ($Matriderm^{(R)}$) was performed on the defective areas, which included the left temporal area, the occipital area, and both eyebrows. Results: The forehead, vertex, right temporal area, and half of the occipital area were successfully replanted, and the hair at the replanted scalp was preserved. As stated above, two-thirds of the scalp survived; the patient could cover the skin graft area with her hair, and could wear a wig. Conclusion: Complete scalp avulsion needs emergent replantation with microsurgical revascularization, but it often leads to serious vital conditions. We report a case with acceptable results, although the microanastomosed vessel was minimal due to the patient's unstable vital signs.

• Journal of Yeungnam Medical Science
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• v.7 no.1
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• pp.69-80
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• 1990

A clinical analysis was done on 23 patients(24 hips) with fracture of the femoral neck, who had been admitted and treated at our Orthopedic department during the period of 4 years, from Jan, 1984 to May 1988. The results were as follows : 1. 23 patients were comprised of 4 males and 19 females, and 11 patients were over 65 years old. 2. 18 cases of 24 cases were due to minor traumas such as slipping down, and for over 65 years old, all cases were due to simple minor traumas, 8 cases were showed a severe osteoporosis, below grade 3 of the Singh's index. 3. 14 cases of 24 cases were displaced subcapital fractures, and 6 cases displaced transcervical fractures. Only 4 cases were the undisplaced transcervical fractures. 4. In treatment of fractures internal fixations after manipulation were performed in 14 cases and primary arthroplasties in 10 cases. Secondary arthroplasties were done in complicated 4 cases of 14 cases treated with internal fixations. 5. Complications after internal fixation were developed in 7 cases out of 14 cases, avascular necrosis in 6, nonunions in 2, pin migrations in 3, and metal failure in 1 case. 6. In 14 arthroplasty immediate surgical fitness of femoral stem were related to late loosening of femoral stem(correlation coefficient r=-0.68, p<0.01).

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.6
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• pp.637-658
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• 2022

TBM tunnel is simple with the iterative process of excavating the ground, building a segment ring-build, and backfilling. Drill & Blast, a conventional tunnel construction method, is more complicated than the TBM tunnel and has some restrictions because it repeats the inspection, drilling, charging, blasting, ventilation, muck treatment, and installation of support materials. However, the preparation work for excavation requires time and cost based on a very detailed plan compared to Drill & Blasting, which reinforces the ground and forms a tunnel after the formation of tunnel portal. This is because the TBM equipment for excavating the target ground determines the success or failure of the construction. If the TBM, an expensive order-made equipment, is incorrectly configured at the assembly stage, it becomes difficult to excavate from the initial stage as well as the main excavation stage. When the assembled shield TBM equipment is dismantled again, and a situation of re-assembly occurs, it is difficult throughout the construction period due to economic loss as well as time. Therefore, in this study, the layout and plan of the site and the assembly process for each major part of the TBM equipment were reviewed for the assembly of slurry shield TBM to construct the largest diameter road tunnel in domestic passing through the Han River and minimized interference with other processes and the efficiency of cutter head assembly and transport were analyzed and improved to suit the site conditions.

• Journal of the Korean Geosynthetics Society
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• v.17 no.4
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• pp.169-177
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• 2018

Glass fiber reinforced polyester (GFRP) composites are widely used as structural materials in harsh environment such as underground pipes, tanks and boat hulls, which requires long-term water resistance. Especially, these materials might be damaged due to delamination between gelcoat and composites through an osmotic process when they are immersed in water. In this study, GFRP laminates were prepared by surface treatment of UPE (unsaturated polyester) gelcoat by vacuum infusion process to improve the durability of composite materials used in underground pipes. The composite surface coated with gelcoat was examined for surface defects, cracking, and hardness change characteristics in water-immersion environments (different temperatures of $60^{\circ}C$, $75^{\circ}C$, and $85^{\circ}C$). The penetration depth of cracks was investigated by micro CT imaging according to water immersion temperature. It was confirmed that cracks developed into the composites material at $75^{\circ}C$ and $85^{\circ}C$ causing loss of durability of the materials. The point at which the initial crack initiated was defined as the failure time and the life expectancy at $23^{\circ}C$ was measured using the Arrhenius equation. The results from this study is expected to be applied to reliability evaluation of various industrial fields where gelcoat is applied such as civil engineering, construction, and marine industry.

• Archives of Plastic Surgery
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• v.46 no.4
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• pp.336-343
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• 2019

Background Sternal rigid plate fixation (RPF) has been adopted in recent years in high-risk cases to reduce complications associated with steel wire cerclage, the traditional approach to sternal closure. While sternal RPF has been associated with lower complication rates than wire cerclage, it has its own complication profile that requires evaluation, necessitating a critical examination from a national perspective. This study will report the outcomes and associated risk factors of sternal RPF using a national database. Methods Patients undergoing sternal RPF from 2005 to 2016 in the American College of Surgeons-National Surgical Quality Improvement Program were identified. Demographics, perioperative information, and complication rates were reviewed. Logistic regression analysis was performed to identify risk factors for postoperative complications. Results There were 381 patient cases of RPF identified. The most common complications included bleeding (28.9%), mechanical ventilation >48 hours (16.5%), and reoperation/readmission (15.2%). Top risk factors for complications included dyspnea (odds ratio [OR], 2.672; P<0.001), nonelective procedure (OR, 2.164; P=0.010), congestive heart failure (OR, 2.152; P=0.048), open wound (OR, 1.977; P=0.024), and operating time (OR, 1.005; P<0.001). Conclusions Sternal RPF is associated with increased rates of three primary complications: blood loss requiring transfusion, ventilation >48 hours, and reoperation/readmission, each of which affected over 15% of the study population. Smokers remain at an increased risk for surgical site infection and sternal dehiscence despite RPF's purported benefit to minimize these outcomes. Complications of primary versus delayed sternal RPF are roughly equivalent, but individual patients may perform better with one versus the other based on identified risk factors.

• Journal of Korea Technology Innovation Society
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• v.22 no.3
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• pp.382-415
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• 2019

This study analyzes the impact of exclusive subcontracting on the input, behavior, and output of innovation in manufacturing industries of Korea. Based on the analysis of pooled cross-sectional data of 6,029 small venture firms, this study proved that the exclusive subcontracting between small venture firms and large enterprises are lowering R&D investment of small venture firms. Second, the innovation activities of small venture firms including the ratio of R&D personnel and the scope of cooperation and partnership with external organizations were lower than those of small venture firms that have non-exclusive or no relations with large enterprises. Third, the innovation performance of small venture firms such as the number of patent applications, the ratio of sales by new products, and the cumulative sales growth rate was lower than those of small venture firms that have non-exclusive or no relations with large enterprises. This study verifies that the exclusive subcontracting relationships significantly weaken the innovation process and performance of small venture firms systematically, resulting in a kind of market failure in which small venture firms have almost no incentive to facilitate innovation.

• Restorative Dentistry and Endodontics
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• v.44 no.3
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• pp.33.1-33.12
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• 2019

Objectives: To evaluate the influence of the restorative technique on the mechanical response of endodontically-treated upper premolars with mesio-occluso-distal (MOD) cavity. Materials and Methods: Forty-eight premolars received MOD preparation (4 groups, n = 12) with different restorative techniques: glass ionomer cement + composite resin (the GIC group), a metallic post + composite resin (the MP group), a fiberglass post + composite resin (the FGP group), or no endodontic treatment + restoration with composite resin (the CR group). Cusp strain and load-bearing capacity were evaluated. One-way analysis of variance and the Tukey test were used with ${\alpha}=5%$. Finite element analysis (FEA) was used to calculate displacement and tensile stress for the teeth and restorations. Results: MP showed the highest cusp (p = 0.027) deflection ($24.28{\pm}5.09{\mu}m/{\mu}m$), followed by FGP ($20.61{\pm}5.05{\mu}m/{\mu}m$), CR ($17.62{\pm}7.00{\mu}m/{\mu}m$), and GIC ($17.62{\pm}7.00{\mu}m/{\mu}m$). For load-bearing, CR ($38.89{\pm}3.24N$) showed the highest, followed by GIC ($37.51{\pm}6.69N$), FGP ($29.80{\pm}10.03N$), and MP ($18.41{\pm}4.15N$) (p = 0.001) value. FEA showed similar behavior in the restorations in all groups, while MP showed the highest stress concentration in the tooth and post. Conclusions: There is no mechanical advantage in using intraradicular posts for endodontically-treated premolars requiring MOD restoration. Filling the pulp chamber with GIC and restoring the tooth with only CR showed the most promising results for cusp deflection, failure load, and stress distribution.

• Journal of the korean academy of Pediatric Dentistry
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• v.46 no.2
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• pp.158-164
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• 2019

The purpose of this study was to compare the bond strength of resin-modified glass ionomer (RMGI) to dentin with saliva contamination at different stages and using different decontamination procedures. Extracted human permanent molars were embedded onto acrylic resin with the dentin surface exposed. Group I was a control group that was conditioned with polyacrylic acid (PAA). Groups II and III were contaminated with saliva before PAA conditioning and Groups IV, V, and VI were contaminated with saliva after PAA conditioning. After saliva contamination, Groups II and IV were dried, Groups III and V were rinsed and dried, and Group VI was additionally conditioned with PAA. After surface treatment, the dentin specimens were filled with RMGI. Group I showed significantly higher bond strength than the other groups. Group VI showed a significantly higher bond strength than the other saliva contaminated groups. However, there were no significant differences in the failure mode between the different groups. Saliva contamination impaired the bond strength of RMGI to dentin, regardless of when the saliva contamination occurred. Decontamination with washing and drying could not improve the shear bond strength of RMGIC. When saliva contamination occurred after PAA conditioning, additional PAA conditioning improved the shear bond strength.

• Journal of Rhinology
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• v.25 no.2
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• pp.75-79
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• 2018

Background and Objectives: To investigate the common site of recurrent epistaxis after initial intervention such as packing and cauterization had failed and to evaluate the efficacy of surgical endoscopic electrocautery. Subjects and Method: Retrospective review of 47 patients with recurrent and uncontrolled idiopathic epistaxis between October 1995 and March 2016. All patients underwent endoscopic examination in the operating room after hospitalization. We performed electrocautery when a bleeding site was found. Results: The most common sites of bleeding were the inferior meatus (28%), sphenoethmoid recess (23%), superior septum around the olfactory cleft (13%), and the posterior end of the middle turbinate (15%). There was no serious complication during the one week after surgery. In 46 (98%) patients, refractory epistaxis was successfully controlled. One patient had recurrent epistaxis after electrocautery and underwent endoscopic sphenopalatine artery ligation. Conclusion: In patients with refractory idiopathic epistaxis after failure of first-line treatment, endoscopic examination through a surgical approach and electrocautery for suspected bleeding are effective.

• Journal of The Korean Society of Clinical Toxicology
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• v.18 no.2
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• pp.78-84
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• 2020

Purpose: In acute acetaminophen poisoning, the administration of N-acetylcysteine (NAC) can effectively treat the main complications, such as kidney injury and liver failure. In the current situation, measurements of the acetaminophen concentration are not checked in the usual medical facilities. Therefore, this study examined the factors of determining the administration of NAC in addition to the stated amount of intake. Methods: The medical records of patients who visited Ajou University Hospital emergency center with acetaminophen poisoning from January 2015 to December 2019 were reviewed retrospectively. One hundred and seventy-nine patients were initially included. Among these patients, 82 patients were finally selected according to the inclusion criteria in the study. The inclusion criteria were as follows: patients who were 15 years of age or older; those whose ingested dose, ingested time, and body weight were clearly identified; and patients whose acetaminophen sampling time was within 24 hours. Patients were divided into two groups: NAC administered vs. non-NAC administered. The following variables were compared in these two groups: ingested dose, ingested dose per body weight, hospital arrival time after ingestion, suicide attempt history, psychiatric disease history, classification of toxic/non-toxic groups, duration of hospitalization, and laboratory results. Results: Univariate analysis revealed the ingested dose per body weight, hospital arrival time after ingestion, suicide attempt history, and psychiatric disease history to be the determining factors in administering NAC. Logistic regression analysis confirmed that the ingested dose per body weight was the only significant factor leading to an NAC treatment decision. (Odds ratio=1.039, 95% Confidential interval=1.009-1.070, p=0.009) Conclusion: The ingested dose per body weight was the only determining factor for administering NAC in patients with acute acetaminophen poisoning. On the other hand, additional criteria or indicators for the NAC administration decision will be necessary considering the inaccuracy of the ingested dose per body weight and the efficiency of NAC administration.