• Journal of Korean Neurosurgical Society
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• v.63 no.4
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• pp.513-518
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• 2020

Objective : Chronic subdural hematoma (CSDH) is one of the most common intracranial hemorrhages. It can be managed with a simple surgical treatment such as burr-hole trephination and drainage. However, it has a relatively high recurrence rate. The mechanisms and risk factors for the recurrence have not yet been clearly identified and studies have reported varying results. Methods : We analyzed 230 patients with CSDH who were treated with burr-hole trephination and drainage at our institution from March 2011 to March 2016. The patients were divided into recurrence and non-recurrence groups and the medical records of each group were used to analyze the risk factors associated with CSDH recurrence. Results : After burr-hole trephination and drainage, CSDH recurrence was observed in 49 (21.3%) of the 230 patients. In univariate analysis, none of the factors showed statistical significance with respect to CSDH recurrence. In multivariate analysis, preoperative antithrombotic medication was the only independent risk factor for CSDH recurrence (odds ratio, 2.407; 95% confidence interval, 1.047-5.531). Conclusion : The present study found that preoperative antithrombotic medication was independently associated with CSDH recurrence.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.203-204
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• 2007

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.5 no.3
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• pp.51-57
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• 2006

Hydro-mechanical punching was developed for preventing burr formation. Circular hole punching and Finite element method(FEM) analysis were conducted to investigate shearing characteristics of this process in comparison with conventional and mechanical counter punching. In this process hydrostatic pressing with appropriate medium was utilized instead of counter punch, which resulted in the delay of the point that the fracture is initiated and clean shearing surface was obtained. FEM analysis was utilized to find out optimum processing parameters and shearing mechanism for burr-free hole punching.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.399-400
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• 2006

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.251-252
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.285-286
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• 2007

• Journal of Trauma and Injury
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• v.26 no.3
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• pp.238-242
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• 2013

Idiopathic thrombocytopenic purpura (ITP) is the condition of having an abnormally low platelet count with an unknown cause. Acute subdural hematomas (ASDHs) usually develop in trauma patients and often involve a high bleeding tendency. However, ITP patients rarely have a large ASDH, and when a traditional decompressive craniectomy is performed on patients with coagulopathy, the mortality rate is higher because of the greater bleeding risk. We report the case of an ITP patient with a large ASDH who treated with a burr-hole trephination and irrigation and who was discharged without any neurological deficit.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.230-235
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• 2003

In the micro hole punching, the size and shape of burr and burnish zone are very important factors to evaluate quality of micro holes which depend on punch-die clearance, stain rate, workpiece material and etc. To get micro holes with small burr and wide burnish zone for industrial demands, not only the parametric study but also a study on fracture behavior in shear band are necessary. In this study, 100 $\mu\textrm{m}$, 25 $\mu\textrm{m}$ micro holes in diameter were fabricated on brass (Cu63/Zn37) and SUS 316 foils as aspect ratio 1:1, and the characteristics of micro holes was investigated comparing with man holes over several mm by scanning electron microscopic views and section views. Like macro hole, micro hole is also composed of 4 portions, rollover, burnish zone, fracture zone and it shows similar fracture behavior in shear band, but？ by high strain rate (10$^2$∼ 10$^3$s$\^$-1/) unlike macro hole fabrication and increment of relative grain size several different results are shown.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.19-23
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• 1996

Deburring and edge finishing technology as the last process of machining operation is required for manufacturing of advanced procesion components, duburring has treated as a difficult problem on going tothe highefficency, automation in the FMS. Removal of butt with various shapes, dimensions and properties coultn't has a standard and has depended on manual treatment. Especially, deburring for cross hole inside owing to passing through out perpendicular to a main hole is more difficult, the electrolytic method is proper as its solution at practical aspects. Therefore, for the high effciency and automation of intermal deburring in the cross hole, development of electrolytic debutting technology is needed. So, the new process in the burr treatment is supposed. In this study, in the eliminating burr inside cross hole, the principle and machining performances of electrochemical deburring by Cubic-Boron-Nitrade abrasive electroplate wheel are investigated, Design and manufacture of CBN electroplated wheel and analysis of characteristics with electrolytic debutting are achieved. Also deburring efficiency and electrolytic performance for cross hole were examined according to electrolytic current and electrolytic deburring condition corresponding to acquired edge quality was found out.

• IE interfaces
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• v.18 no.3
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• pp.247-252
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• 2005

In the automated production environment in the present days, the minimization of manual operation becomes a very important factor in increasing the efficiency of the production system. The exit burr produced through the milling operation on the edge of workpiece usually requires manual deburring process to enhance the level of precision of the resulting product. So far, researchers have developed various methods to understand the formation of exit burr in cutting process. One method to analytically identify the formation of exit burr was to use the geometrical information of CAD and CAM data used in automated machining. This method, in turn, generated the information resulting from the analysis such as burr type, cutting region, and exit angle. Up to now, the geometrical data were restricted to the single feature and single path. In this paper, a method to deal with the complicated geometric features such as line segment, arc, hole, and spline will be presented and validated using the field data. This method also deals with the complex workpiece shape which is a combination of multiple features. As for the cutting path, multiple tool path is analyzed in order to simulate the real cutting process. All this analysis is combined into a Windows based software and real data are used to validate the program in the conclusion.