• Journal of the Korean Society of Radiology
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• v.84 no.2
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• pp.418-426
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• 2023

Purpose Practical challenges are encountered in percutaneous intravascular procedures when applied to markedly angulated branching vessels. Herein, we introduced a folded-loop guidewire remodeling technique-the guidewire-shaping technique-to overcome difficult catheterization. Materials and Methods First, the tip of a 0.014-inch micro-guidewire was manually shaped like a pigtail loop. Second, the shaped guidewire was introduced into the microcatheter and was preloaded into the hollow metal introducer for suitability with the microcatheter hub. Gentle rotation of the guidewire after release from the microcatheter can create the preshaped pigtail loop configuration. On pulling back, the loop loosened, the configuration was changed to a small U-shaped tip, and the guidewire tip was easily introduced into the target artery. Results Between December 2019 and January 2022, the described technique was used in 64 patients (male/female, 49/15; mean age, 66.8 ± 9.5 years) for selective arterial embolization, after failed attempts with the conventional selection technique. The technique was successful in 63/64 patients (98%). The indications of embolization include transcatheter arterial chemoembolization, gastrointestinal bleeding, hemoptysis, trauma-induced bleeding, and tumor bleeding. Conclusion The folded-loop guidewire remodeling technique facilitates the catheterization of markedly angulated branching arteries; when usual catheterization method fails.

• Journal of Magnetics
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• v.21 no.4
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• pp.616-621
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• 2016

This paper presents a new multifunctional active guidewire system for medical applications that uses a magnetic microrobot. The study demonstrated that the proposed microrobot system could swim and be controlled under Low-Reynolds-number (Re) environments in blood vessel models. The prototype of the robotic guidewire, which is driven within a three-axis Helmholtz coil system, consists of a guide-wire, spiral blade, drilling tip, and permanent magnet. The spiral-type microrobot showed stable active locomotion between 3 kA/m and 9.1 kA/m under driving frequency up to 70 Hz in a silicone oil (of viscosity 1000 cst). The microrobot produced a maximum moving velocity of $8.08{\times}10^{-3}m/s$ at 70 Hz and 9.1 kA/m. In particular, the robotic guidewire produced 3D locomotion with drilling in the three-axis Helmholtz coil system. We verified active locomotion, towing of guidewire, steering, and drilling of the proposed robotic guidewire system through experimental analyses.

• Journal of The Korean Society of Emergency Medicine
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• v.29 no.6
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• pp.636-640
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• 2018

Objective: Central venous catheter (CVC) misplacement can result in incorrect readings of the central venous pressure, vascular erosion, and intravascular thrombosis. Several studies have examined the correlation between the guidewire J-tip direction and misplacement rate. This study examined whether the guidewire J-tip direction (cephalad vs. caudad) affects the misplacement rate in right subclavian venous catheterization. Methods: This prospective randomized controlled study was conducted between February 2016 and February 2017. The subjects were divided into two groups (cephalad group vs. caudad group) and the misplacement rate was compared according to guidewire J-tip direction in each group. Results: Of 100 patients, the cephalad and caudad groups contained 50 patients each. The age, sex, and operator experience were similar in the two groups. In the cephalad group, misplacement of CVC insertion into the ipsilateral internal jugular vein occurred in two cases. In the caudad group, misplacement of CVC insertion into the contralateral subclavian vein occurred in one case, with loop formation in the brachiocephalic trunk in one case. Guidewire J-tip direction showed no significant correlation with CVC misplacement. Conclusion: The guidewire J-tip direction does not influence the rate of misplacement.

• Journal of Chest Surgery
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• v.39 no.8 s.265
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• pp.640-642
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• 2006

Entrapment and fracture of coronary angioplasty hardware are rare complications of percutaneous coronary intervention (PCI). Retained guidewire should be removed either percutaneously or surgically, because it could serve as a nidus for thrombus formation. We report on a successful surgical retrieval of entrapped PCI guidewire and subsequent bypass grafting of the affected coronary vessel.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.837-838
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• 2012

• The Korean Journal of Pain
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• v.19 no.2
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• pp.207-212
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• 2006

Background: The epidural injection technique is a commonly used intervention in the management of chronic spinal pain, which has the advantage of delivering various drugs, such as local anesthetics or steroids, in higher concentrations to the inflamed nerve root. A guidewire-reinforced epidural catheter was introduced through a Tuohy needle during the caudal epidural procedure, with a catheter threaded into the affected nerve roots and the spread-pattern of contrast agents observed under fluoroscopy. Methods: Sixty-seven patients with low back pain, who showed evidence of a herniated nucleus pulposus on magnetic resonance imaging, were included. All patients received fluoroscopically guided caudal epidural injections, with the guidewire-reinforced epidural catheter introduced through a Tuohy needle and threaded either to the right or left side toward the target nerve roots. After confirming the catheter tip position at the affected nerve root, 2 ml increments of contrast agents (up to 6 ml) were injected, and their corresponding AP fluoroscopic views were obtained. Three radiologists reviewed all the radiographic findings and measured the proportion of the area of contrast spread at the side of target nerve roots. Results: Greater proportion of the area of contrast spread was observed at the side of the target nerve roots (P < 0.0001). At each level of contrast injection (2-⁣, 4- ⁣ and 6 ml), more than 70% of the spread of contrast dye was observed at the side of the target nerve roots in 85%, 70%, and 55% of cases, respectively. Conclusions: The combination of a caudal epidural injection and use of a guidewire-reinforced epidural catheter significantly enhances the target specificity, as revealed by the selective spread of contrast dye at the side of target nerves.

• Journal of Trauma and Injury
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• v.33 no.3
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• pp.140-143
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• 2020

Resuscitative endovascular balloon occlusion of the aorta (REBOA) has been accepted as an adjunct procedure for non-compressible torso hemorrhage in patients with hemorrhagic shock. With appropriate indications, REBOA should be performed for resuscitation regardless of the physician's specialty. Despite its effectiveness in traumatized patients with hemorrhagic shock, performing REBOA has been challenging due to physicians' lack of experience. Even though training in endovascular skills is mandatory, many physicians cannot undergo sufficient training because of the limited number of endovascular simulation programs. Herein, we share simulation video clips, including those of a vascular circuit model for simulation; sheath preparation; long guidewire and balloon catheter preparation; ultrasound-guided arterial access; sheath insertion or upsizing; and balloon positioning, inflation, and migration. The aim of this study was to provide educational video clips to improve physicians' endovascular skills for REBOA.

• Korean Journal of Radiology
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• v.21 no.8
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• pp.935-945
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• 2020

We retrospectively reviewed the cases in which complications occurred during below-the-knee (BTK) endovascular treatments that were performed at our hospital from 2005 to 2014. Several interesting cases have been described herein. All the patients had diabetes and non-healing wounds on their feet and/or rest pain in their foot or leg, and therefore, endovascular treatment was performed for the BTK arteries of the affected lower extremity. The complications that occurred during the procedure were classified into six categories-vascular spasm, flow limiting dissection, perforation, broken guidewire, distal thromboembolism, and unusual puncture site bleeding. Each complication has its own solutions and management. We discuss these different classes of complications and describe how cases of each type were managed.

• Clinical Endoscopy
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• v.56 no.2
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• pp.164-168
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• 2023

When diagnosing the nature of biliary strictures, it is sometimes difficult to perform non-invasive methods such as ultrasound, spiral computed imaging, magnetic resonance imaging, or endoscopic ultrasonography. Thus, treatment decisions are usually based on biopsy results. However, brush cytology or biopsy, which is widely used for biliary stenosis, has limitations owing to its low sensitivity and negative predictive value for malignancy. Currently, the most accurate method is bile duct tissue biopsy under direct cholangioscopy. On the other hand, intraductal ultrasonography administered under the guidance of a guidewire has the advantages of easy administration and being less invasive, allowing for adequate examination of the biliary tract and surrounding organs. This review discusses the usefulness and drawbacks of intraductal ultrasonography for biliary strictures.

• Journal of Trauma and Injury
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• v.36 no.4
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• pp.451-453
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• 2023

We introduce a convenient method of urethrography before catheterization for patients with pelvic trauma that can be used in a resuscitation area. A 10-mL syringe without a needle was used. X-ray contrast medium (Iohexol, 300 mg I/mL) was administered through the urethral orifice using a 10-mL syringe without needle and a simple pelvic anteroposterior film was taken (70 kilovolt [peak], 50 mAs). A 36-year-old soldier with a saddle injury from a gun barrel was taken to a trauma center. He had a pelvic fracture and complained of hematuria. Bedside urethrography above described was performed. The anterior urethra showed nonspecific findings, but dye leaked from the posterior urethra. Bedside Foley catheter insertion was attempted, but the catheter could not be advanced past the membranous urethra. Thereafter, suprapubic catheterization was performed. On the day of the injury, iliac artery embolization was carried out. The dislocated sacroiliac joint was also treated using open reduction and internal fixation. On hospital day 7, guidewire Foley insertion was performed. This bedside urethrography technique is simple and useful for pelvic fractures in which urethral injury is suspected.