• Journal of the Microelectronics and Packaging Society
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• v.24 no.2
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• pp.29-35
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• 2017

In this paper, we investigated a manufacturing process of metal micro-wire interconnection on submillimeter diameter catheter. Over the years, flexible electronic researches have focused on flexible plane polymer substrate and micro electrode manufacturing on its surface. However, a curved polymer substrate, such as catheter, is very important for medical application. Among many catheters, importance of submillimeter diameter steerable catheter is increasing to resolve the several limitations of neurosurgery. Steering actuators have been researched for realizing the steerable catheter, but there is no research about practical wiring for driving these actuators. Therefore we developed a new manufacturing process for metal micro-wire interconnection on submillimeter diameter catheter. We designed custom jigs for alignment of the metal micro-wires on the submillimeter diameter catheter. An UV curing system and commercial products were used to reduce the manufacturing time and cost; Au micro-wire, UV curable epoxy, UV lamp, and submillimeter diameter catheter. The assembled catheter was characterized by using an optical microscope, a resistance meter, and a universal testing machine.

• The Korean Journal of Pain
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• v.20 no.2
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• pp.100-105
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• 2007

Background: Ginseng has been used to manage various types of pain in folk medicine. This study characterized the effect of treatment with intrathecal ginsenosides, the active components of ginseng in a postoperative pain model. Methods: Male Sprague-Dawley rats were implanted with lumbar intrathecal catheters. An incision was made in the plantar surface of the hindpaw. Withdrawal thresholds following the application of a von Frey filament to the wound site were measured. To determine the role of the opioid or GABA receptors following treatment with the ginsenosides, naloxone, bicuculline (a $GABA_A$ receptor antagonist), and saclofen (a $GABA_B$ receptor antagonist) were administered intrathecally 10 min before the delivery of the ginsenosides and the changes of the withdrawal thresholds after application of the von Frey filament were Observed. Results: Treatment with the intrathecal ginsenosides increased the withdrawal threshold in a dose dependent manner. Pre-treatment with intrathecal naloxone reversed the antinociceptive effect of the ginsenosides. However, pre-treatment with intrathecal bicuculline and saclofen failed to have an effect on the activity of the ginsenosides. Conclusions: These results suggest that ginsenosides are effective to alleviate the postoperative pain evoked by paw incision. The opioid receptor, but not GABA receptors, may be involved in the antinociceptive action of the ginsenosides at the spinal level.

• Journal of Korean Neurosurgical Society
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• v.60 no.5
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• pp.604-609
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• 2017

Objective : An adjustable Ghajar guide is presented to improve the accuracy of the original Ghajar guide technique. The accuracy of the adjustable Ghajar guide technique is also investigated. Methods : The coronal adjustment angle from the orthogonal catheter trajectory at Kocher's point is determined based on coronal head images using an electronic picture archiving and communication system. For the adjustable Ghajar guide, a protractor is mounted on a C-shaped basal plate that is placed in contact with the margin of a burrhole, keeping the central $0^{\circ}$ line of the protractor orthogonal to the calvarial surface. A catheter guide, which is moved along the protractor and fixed at the pre-determined adjustment angle, is then used to guide the ventricular catheter into the frontal horn adjacent to the foramen of Monro. The adjustable Ghajar guide technique was applied to 20 patients, while a freehand technique based on the surface anatomy of the head was applied to another 47 patients. The accuracy of the ventricular catheter placement was then evaluated using postoperative computed tomography scans. Results : For the adjustable Ghajar guide technique (AGT) patients, the bicaudate index ranged from 0.23 to 0.33 ($mean{\pm}standard$ deviation [SD] : $0.27{\pm}0.03$) and the adjustment angle ranged from $0^{\circ}$ to $10^{\circ}$ ($mean{\pm}SD:5.2^{\circ}{\pm}3.2^{\circ}$). All the AGT patients experienced successful cerebrospinal fluid diversion with only one pass of the catheter. Optimal placement of the ventricular catheter in the ipsilateral frontal horn approximating the foramen of Monro (grade 1) was achieved in 19 patients (95.0%), while a suboptimal trajectory into a lateral corner of the frontal horn passing along a lateral wall of the frontal horn (grade 3) occurred in 1 patient (5.0%). Thus, the AGT patients experienced a significantly higher incidence of optimal catheter placement than the freehand catheterized patients (95.0% vs. 68.3%, p=0.024). Moreover, none of the AGT patients experienced any tract hemorrhages along the catheter or procedure-related complications. Conclusion : The proposed adjustable Ghajar guide technique, using angular adjustment in the coronal plane from the orthogonal trajectory at Kocher's point, facilitates accurate freehand placement of a ventricular catheter for hydrocephalic patients.

• Journal of the Korean Society of Radiology
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• v.15 no.5
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• pp.621-628
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• 2021

Prior studies on frequency-related image quality analysis of intravascular ultrasound catheters are lacking both in Korea and abroad. Therefore, this study was conducted to prepare a standard for measuring the image quality using the program and to suggest a measuring method to researchers related to the quality analysis of intravascular ultrasound images. For the target, the vessel lumen size is 3.0 - 4.0 mm. Before using intravascular ultrasound, thoroughly clean the ultrasound catheter so that no air or foreign substances enter it. Normal vascular images and lesion vascular images of sufficiently dilated images were used. As a standard image acquisition method, the image of the end-systolic section, which has the best evaluation of vascular lesions when using intravascular ultrasound, was acquired retrospectively through the DCAS PACS program to set the standard. When setting the measurement method criteria, we proposed a standard setting method that corresponds to the concentric and eccentric circles of normal and lesion vessels. By applying this criterion, we proposed a method for measuring the lumen and lateral cavities of normal and lesion vessels of interest and background area. In conclusion, if the image quality of intravascular ultrasonography is measured through the method devised by these researchers, consistent quality measurement is possible regardless of the type of intravascular ultrasound catheter. Therefore, it is thought that it can be applied as a guideline for the actual image quality measurement method in the study related to intravascular ultrasound image quality.

• Journal of the Korean institute of surface engineering
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• v.55 no.6
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• pp.390-397
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• 2022

Parylene-C which was mainly used for industries such as electronics, machinery and semiconductors has recently been in the spotlight in the medical field due to its properties such as corrosion resistance and biocompatibility. In this study we intend to derive a plan to improve the bonding strength of Parylene-C coating with the SUS304 base material for medical use which can be applied to various medical fields such as needles, micro needles and in vitro diagnostic device sensors. Through plasma pretreatment the bonding strength between Parylene-C and metal materials was improved. It was confirmed that the coated surface was hydrophobic by measuring the contact angle and the improvement of the surface roughness of the sample manufactured through CNC machining was confirmed by measuring the surface roughness with SEM. Through the above results, it is thought that it will be effective in increasing usability and reducing pain in patients by minimizing friction when inserting medical devices and in contact with skin. In addition it can be applied to various application fields such as human implantable stents and catheters, and is expected to improve the performance and lifespan of medical parts.

• Tuberculosis and Respiratory Diseases
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• v.84 no.2
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• pp.134-139
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• 2021

Background: Intrapleural urokinase is one of the most widely used fibrinolytic agents in the treatment of complicated parapneumonic effusion (CPPE). However, little research has been performed on the optimal urokinase dosage. The aim of this study was to evaluate the treatment efficacy of half dose urokinase compared with conventional dose urokinase. Methods: We retrospectively enrolled 92 patients with CPPE or empyema who underwent intrapleural urokinase treatment at two tertiary hospitals. Patients received antibiotics, chest tube drainage, and other treatments as part of routine care. The primary outcome was the treatment success rate in the half dose urokinase group (50,000 IU daily for maximal 6 days) and the conventional dose urokinase group (100,000 IU daily). Treatment success was defined as clinical and radiological improvements without surgical treatment or re-admission within one month. Results: Forty-four patients received half dose urokinase, whereas 48 patients were treated with conventional dose urokinase. Both groups were relatively well matched at baseline, excluding higher serum white blood cell count and higher empyema prevalence in the half dose urokinase group. The treatment success rate was not different between the two groups (p=0.048). There were no differences in the rate of in-hospital death and surgical treatment, hospitalization duration, and indwelling catheter duration. In the multivariate analysis, urokinase dose was not a predictor of treatment success. Conclusion: Half dose intrapleural urokinase is equally effective conventional dose urokinase in treating patients with CPPE or empyema.

• Journal of Korean Neurosurgical Society
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• v.64 no.5
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• pp.732-739
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• 2021

Objective : Early successful reperfusion is associated with favorable outcomes in acute ischemic stroke (AIS). The purpose of this study was to achieve successful recanalization by a combined mechanical thrombectomy technique, the Aspiration-Retriever Technique for Stroke (ARTS), which is composed of a flexible large lumen distal access catheter and a retrievable stent as the first-line strategy of mechanical thrombectomy. Methods : We retrospectively reviewed 62 patients with AIS who underwent mechanical thrombectomy from 2018 to 2019 at our institute by a senior neurointerventionalist. Among them, patients who were treated using the ARTS technique with the soft torqueable catheter optimized for intracranial access (SOFIA^®; MicroVention-Terumo, Tustin, CA, USA) as the first-line treatment were included. Patients who had tandem occlusions or underlying intracranial artery stenosis were excluded. The angiographic and clinical outcomes were evaluated. The angiographic outcome was analyzed by the rate of successful recanalization, defined as a Thrombolysis in Cerebral Infarction score of 2b or 3 at the end of all procedures and the rate of successfully achieving the first pass effect (FPE), defined as complete recanalization with a single pass of the device. The clinical outcomes included the National Institutes of Health Stroke Scale (NIHSS) score, modified Rankin Scale (mRS), and mortality. Results : A total of 27 patients (mean age, 59.3 years) fulfilled the inclusion criteria. The successful recanalization rate was 96% (n=26) while the FPE rate was 41% (n=11). The mean post-procedural NIHSS change was -3.0. Thirteen patients (48%) showed good clinical outcomes after thrombectomy with the ARTS technique (mRS at 90 days ≤2). Postoperative complications occurred in seven of 25 patients : hemorrhagic transformation in six patients (22%) and distal embolization in one patient (4%). Mortality was 15% (n=4). Conclusion : Although the clinical outcomes using the ARTS technique with a flexible large lumen distal access catheter performed as the frontline thrombectomy in patients with AIS were not significantly superior than those of other studies, this study showed a high rate of successful endovascular recanalization which was comparable to that of other studies. Therefore, ARTS using the SOFIA^® catheter can be considered as the first choice of treatment for AIS due to large vessel occlusion.

• Applied Chemistry for Engineering
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• v.33 no.5
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• pp.545-550
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• 2022

As a result of the rapid entry into an aging society and westernized eating habits, the number of heart disease patients caused by angina pectoris, myocardial infarction, and high blood pressure has increased by more than 100,000 over five years. Heart disease has consistently ranked second in the cause of death in Korea over the past eight years, and medical expenses consumed annually reach 6 trillion won. While various treatments are being proposed for more patients, drug-coated balloon catheters have been developed and gradually commercialized to solve the disadvantages of stent implantation such as restenosis and increased risk of bleeding due to long-term double antiplatelet medication. In Korea, it began to use a drug-coated balloon catheter with the first release of it called "SeQuent Please^Ⓡ (Bibrown Korea)" in 2010. Its demand increased gradually as insurance benefits were applied in 2012. Drug-coated balloon angioplasty is increasing in use not only in Korea but also around the world, especially in the Asia-Pacific region, including Japan. Until now, the demand for domestic products is increasing, and if the efficiency in vivo and clinical trials is proven in the future, it is expected to be an effective procedure compared to high-risk stent implantation.

• Journal of Chest Surgery
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• v.55 no.2
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• pp.118-125
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• 2022

Background: A time course analysis was undertaken to evaluate how perioperative process-of-care and outcome measures evolved after implementation of an enhanced recovery after thoracic surgery (ERATS) program. Methods: Outcome and process-of-care measures were compared between patients undergoing major elective thoracic surgery during a 9-month pre-ERATS implementation period to those at 1-3, 4-6, and 7-9 months post-ERATS implementation. Outcome measures included length of stay, the 30-day readmission rate, 30-day emergency department visits, and minor and major adverse events. Process measures included first time to activity, out-of-bed, ambulation, fluid diet, diet as tolerated, as well as removal of the first and last chest tube, epidural, patient-controlled analgesia, and Foley and intravenous catheters. Results: In total, 704 patients (352 pre-ERATS, 352 post-ERATS) were included. Mobilization-related process measures, including time to first activity (16.5 vs. 6.8 hours, p<0.001), out-of-bed (17.6 vs. 8.9 hours, p<0.001), and ambulation (32.4 vs. 25.4 hours, p=0.04) saw statistically significant improvements by 1-3 months post-ERATS implementation compared to pre-ERATS. Time to Foley removal improved by 4-6 months post-ERATS (19.5 vs. 18.2 hours, p=0.003). Outcome measures, including the 30-day readmission rate and emergency department visits, steadily decreased post-ERATS. By 7-9 months post-ERATS, both minor (18.2% vs. 7.9%, p=0.009) and major (13.6% vs. 4.4%, p=0.007) adverse events demonstrated statistically significant improvements. Length of stay trended towards improvement from 6.2 days pre-ERATS to 4.8 days by 7-9 months post-ERATS (p=0.06). Conclusion: The adoption of ERATS led to improvements in multiple process-of-care measures, which may collectively and gradually achieve optimization of clinical outcomes.

• Journal of the Korean Society of Radiology
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• v.16 no.6
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• pp.735-740
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• 2022

In order to reduce side effects such as rectal bleeding in the Brachytherapy, the rectal retractor and wet gauze have been used to increase the distance between the rectum and the tandem. However, there were disadvantages that it was difficult to insert through a narrow entrance into the vagina and poor reproducibility. Also, based on the CT image of the selected catheter, the distance from the tandem to the rectum with or without the balloon catheter was checked and the reduction of the dose to the rectum was confirmed. As a result of the experiment, catheter No. 7 was selected considering the maximum balloon size at a level that does not affect the distance between the start point of the balloon and the end of the catheter, and the ovoid applicator. Based on the CT image of the selected catheter, the degree of expansion according to the presence or absence of the balloon catheter was compared, and it was found that the distance difference was 0.3 - 1 cm. In addition, it was confirmed that a decrease of about 32% was observed due to this distance difference. Therefore, the actual clinical application of the selected catheter can be used as a substitute for the existing rectal retractor and wet gauze.