• Journal of Korean Neurosurgical Society
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• v.37 no.4
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• pp.300-302
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• 2005

The authors report a case of hyperacute, massive hemorrhage in the left basal ganglia with severe midline shift that was treated successfully by the ultrasound-monitored free hand aspiration technique. Every effort was made to shorten time until removal of considerable amount of the hematoma and minimize duration of cerebral herniation, avoiding additional irreversible neurological deficit. A burr hole aspiration technique was preferred to standard craniotomy procedure, and any time-consuming procedures such as stereotactic frame application were abandoned. A burr hole was localized on the basis of computed tomography images simply and quickly with a ruler, and safety of the aspiration procedure was augmented by real-time ultrasound monitoring. Such minimally invasive technique relieved cerebral herniation successfully while avoiding time consumption and the morbidity of major craniotomy procedure. Early resuscitation of the patient with cerebral herniation in this case resulted in excellent recovery of the patient's neurological deficit. The patient's mentality started to improve rapidly and was clear six months after the surgery.

• Journal of Korean Neurosurgical Society
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• v.38 no.2
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• pp.116-120
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• 2005

Objective : The aim of this study is to analyze the clinical symptoms, radiological changes, interval from first operation to symptom recurrence and to propose the proper treatment method for re-operated patients following chronic subdural hematoma surgery. Methods : Between January 1992 and April 2003, 18 of 138patients of chronic subdural hematoma repeatedly underwent surgical treatment. The symptoms, mental status by Bender grade, radiological hematoma size and midline shifting, interval from symptom onset to diagnosis, surgical method and prognosis by Glasgow outcome scale[GOS] between the first attack and the recurrence were compared. Results : The symptoms at the time of recurrence were nearly the same as with the first attack, but two patients[2/18, 11.1%] showed a more declined mentality. In addition, the recurred hematoma sizes were the same or large than those previously found. Many patients were recurred within two weeks[13/18, 72.2%]. Most patients were operated on using the previous burr hole, with the exception of one patient who recurred at a different site. All patients had a good prognosis more than GOS 4 [GOS 4:4, GOS 5:12], but two died due to extracranial complication and infection. Conclusion : These results suggest that the early diagnosis and treatment are important, mostly recurred same symptoms within two weeks. Re-operation using the previous burr hole site is a good method.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.1
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• pp.134-140
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• 2017

CFRP has many industrial applications due to its low weight and high strength properties. CFRP is a composite material composed of carbon fibers embedded in a polymer matrix; it provides excellent resistance to fatigue wear, corrosion, and breakage due to fatigue. It is increasingly demanded in aircraft, automotive, and medical industries due to its superior properties to aluminum alloys, which were once considered the most suitable for specific applications. The basic machining methods of CFRP are drilling and route milling. However, in the case of drilling, the delamination of each layer, uncut fiber, resin burning, spalling, and exit burrs are barriers to successful application. This paper investigates the occurrence of exit burrs when drilling holes with ultrasonic vibration. Depending on design parameters such as the point angle, the characteristics of hole drilling were identified and appropriate machining conditions were considered.

• Journal of Korean Neurosurgical Society
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• v.55 no.4
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• pp.218-221
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• 2014

Chronic subdural hematoma (CSDH), which rarely happens in the young, is thought to be a disease of the elderly. Whereas unspecific symptoms and insidious onset in juveniles and young adults, as a result of its relative low morbidity, CSDH is usually neglected even undertreated in the young. Through the three cases and review of the current literature on this subject, we tried to illustrate the clinical and etiopathological characteristics of this entity and find out the most appropriate treatment strategy. We report three young CSDH patients with different but similar symptoms. The present histories, tests and examinations revealed different predisposing factors accounting for the genesis of CSDH. Their preoperative symptoms were all resolved with burr hole and drainage operation. Juveniles and young adults suffering from CSDH differ from that of their elderly counterparts in their clinical and etiopathological characteristics. Although trauma is the most important risk factor in young and old CSDH patients, some other predisposing factors may exist. Burr hole and drainage surgery could resolve the problem most of the time. But further tests and examinations even specific management should be made in some cases.

• 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.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.1084-1087
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• 1997

In this paper, we developed the micro NCT system for punching the thin plates, which is driven is driven by the standalone type microprocessor. In order to adjust the alignment between the punch and die in-situ punching procedures, the non-contact type laser sensor for measuring the burr and micro-driving system for punching die with using the differential screw are developed. The height of burr in four directions in the punched hole of test specimen are measured, and the measured data are transferred to the personal computer by RS232C serial communication technology. In the personal computer, by using the graphic user interface type monitoring program and data handling procedures which includes the filtering algorithms, the direction and length of movement of the die position is decided and these data are transferred back to the microprocessor. The microprocessor drives the micro positioning stage based on these data. Even if this method is not a perfect solution for the in-situ alignment in micro punching, but this alignment methodology is accomplished in the same stage just after the punching that we hope to solve the alignment problem in the punching system based on this technology.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.4
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• pp.109-117
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• 2016

For efficient deburring of burrs that form inside mechanical parts after drilling, new special deburring tool was developed specifically for the burr found at intersecting holes. In this paper, the process for finding ideal cutting conditions has been carried out to identify the efficient performance of deburring using a new tool. The burrs at the entrance and exit surface were analyzed for efficient removal. The surface roughness after deburring was also reviewed for better performance. In addition, the influence of the feed rate on deburring quality was analyzed for improved productivity. Through this process, a new deburring tool can be applied effectively to remove burrs formed at intersecting holes.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.12
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• pp.50-56
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• 2007

Femtosecond laser ablation of the Invar alloy and hole drilling for a shadow mask are studied. We used a regenerative amplified Ti-sapphire laser with a 1kHz repetition rate, 184fs pulse duration and 785nm wavelength. Femtosecond laser pulse was irradiated on the Invar alloy with air blowing at the condition of various laser peak power. An ablation characteristic of the Invar alloy was appeared non-linear at $125J/cm^2$ of energy fluence. For the application to a shadow mask, the hole drilling of the Invar alloy with the cross section of a trapezoidal shape was investigated. The ablated micro-holes were characterized using an atomic force microscopy(AFM). The optimal condition of hole pattern f3r a shadow mask was $4\;{\mu}m$ z-axis feed rate, 0.2mm/s circular velocity, $26.4{\mu}J$ laser peak power. With the optimal processing condition, the fine circular hole shape without burr and thermal damage was achieved. Using the femtoseocond laser system, it demonstrates excellent tool for the Invar alloy micro-hole drilling without heat effects and poor edge.

• Journal of Korean Neurosurgical Society
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• v.29 no.6
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• pp.748-753
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• 2000

Objectives : A 10-year retrospective clinical study was undertaken to determine the differences between two groups according to age at presentation(group A, under 50 ; B, over 50). Methods : We analyzed 468 cases with chronic subdural hematoma admitted to the department of neurosurgery in our hospital from January 1987 to December 1996. The patients were divided into two groups according to age at presentation(group A, under 50 ; B, over 50). Results : 1) The number of group A was 126 cases(26.9%) and that of group B was 342 cases(73.1%), respectively. Males were more frequently involved than females in each group. 2) There noted a history of head trauma in 88.9% of group A and 92.4% of group B. Forty-nine patients(38.9%) of group A and 103 cases(30.1%) of group B revealed a history of alcoholism. 3) Group A patients presented with symptoms of increased intracranial pressure such as headache(75.% ), nausea and vomiting(68.0%). However, Group B patients had more frequent mental changes(84.0%) and focal neurological deficits such as hemiparesis(76.5%). 4) Onset of symptom and its duration was shorter in group A than group B. 5) Six patients among 441 cases(1.4%) treated with burr hole drainage and two patients of 27 cases(5.4%) with craniotomy died, and all of these were group B patients. The two cases among six patients with burr hole drainage developed huge intracerebral hemorrhage and brain stem hemorrhage, respectively. Conclusion : In treating patients with chronic subdural hematoma, distinguishing between two age groups is quite helpful to determine treatment strategies.

• Journal of Korean Neurosurgical Society
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• v.30 no.sup2
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• pp.294-299
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• 2001

Objectives : CT-guided stereotactic evacuation for spontaneous intracerebral hemorrhage can minimize the brain damage and can be performed safely and simply under local anesthesia. But that procedure is time consuming and has a risk of rebleeding because of the stress during head pin fixation. So authors describe easy and precise guidelines for FHA of putaminal hemorrhage without stereotactic instrument. Methods and Materials : We analyzed the data of 298 patients who underwent CT-guided stereotactic aspiration of putaminal hematoma in our hospital between January 1990 and December 2000. We divided the patients into three groups according to the location of hematoma : anterior portion, middle portion and posterior portion of putamen. Total number of catheters inserted into the hematoma were 345 and there were with regard to the direction and depth of catheters. Results : Proposed guidelines of catheter insertion to putaminal hemorrhage in our institution. 1) hematoma at the anterior portion of putamen ; Direction of catheter was the midpupillary line of the eye and the point intersecting a line drawn from the burr hole to a point between external auditory meatus(EOM) and 1cm posterior to EOM. Depth of catheter was 6-6.5cm. 2) hematoma at the middle portion of putamen ; Direction of catheter was the midpupillary line of the the eye and the point intersecting a line drawn from the burr hole to a point between 1cm and 2cm posterior to EOM. Depth of catheter was 6.5-7cm. 3) hematoma at the posterior portion of putamen ; Direction of catheter was 15 degree laterally from the midpupillary line of the eye and the point intersecting a line drawn from the burr hole to a point between 2cm and 3cm posterior to EOM. Depth of catheter was 7-7.5cm. We have performed FHA of putaminal hemorrhage in 48 cases according to this guideline. All catheter were inserted exactly at the center of hematoma and average operation time was about 30 minutes. Conclusion : Our proposed guidelines for putaminal hemorrhage are considered to be safe and simple method with similar accuracy and rapid decompression compared with traditional stereotactic method. Main advantages of this technique were unnecessity of stereotactic frame application and less time requirement for hematoma removal.