Technical Reports of Endoscopic Retrograde Cholangiopancreatography Guidewires on the Basis of Physical Properties

권창일,고동희,송태준,박원석,이돈행,정석 대한소화기내시경학회 2020 Clinical Endoscopy Vol.53 No.1

Background/Aims: Using an appropriate guidewire can increase the success rate of selective cannulation in endoscopic retrogradecholangiopancreatography. The purpose of this technical study was to investigate the characteristics of each guidewire type and toevaluate its effciency and rapidity of insertion. Methods: We conducted a three-point bending test using a universal testing machine to investigate the flexibility and bending featuresof each guidewire. 3D-printed silicone tubes with various types of stricture and a hand-made biliary tree silicone model with sixstrandedintrahepatic ducts were used to evaluate the success rate and insertion time of each guidewire. Results: In the three-point bending test, the characteristics of each guidewire were classified. We found that the bending strengthsand times were independent of shaft thickness. Using two in vitro biliary duct models, we determined that the success rate and totalinsertion time were better for guidewires with a resilient shaft and angled tip than for other types of guidewires (p<0.001). Althoughthickness of the guidewire affected the success rate (p<0.05), it did not affect the total insertion time (p≥0.05). Conclusions: Among several types of guidewire, some factors (resilient shaft, highly flexible, and angled tip) appeared to be associatedwith the effciency and rapidity of the guidewire insertion.

Bowel Obstruction Caused by an Intramural Duodenal Hematoma: A Case Report of Endoscopic Incision and Drainage

권창일,고광현,홍성표,황성규,박필원,임규성,김효영 대한의학회 2009 Journal of Korean medical science Vol.24 No.1

Complications associated with an intramural hematoma of the bowel, is a relatively unusual condition. Most intramural hematomas resolve spontaneously with conservative treatment and the patient prognosis is good. However, if the symptoms are not resolved or the condition persists, surgical intervention may be necessary. Here we describe internal incision and drainage by endoscopy for the treatment of an intramural hematoma of the duodenum. A 63-yr-old woman was admitted to the hospital with hematemesis. The esophagogastroduodenoscopy (EGD) showed active ulcer bleeding at the distal portion of duodenal bulb. A total of 10 mL of 0.2% epinephrine and 2 mL of fibrin glue were injected locally. The patient developed diffuse abdominal pain and projectile vomiting three days after the endoscopic treatment. An abdominal computed tomography revealed a very large hematoma at the lateral duodenal wall, approximately 10×5 ㎝ in diameter. Follow-up EGD was performed showing complete luminal obstruction at the second portion of the duodenum caused by an intramural hematoma. The patient’s condition was not improved with conservative treatment. Therefore, 21 days after admission, endoscopic treatment of the hematoma was attempted. Puncture and incision were performed with an electrical needle knife. Two days after the procedure, the patient was tolerating a soft diet without complaints of abdominal pain or vomiting. The hematoma resolved completely on the follow-up studies.

Anisotropic superconductivity of high quality FeSe1-x Single crystal

권창일,옥종목,김준성 한국초전도.저온공학회 2014 한국초전도저온공학회논문지 Vol.16 No.4

We investigate the upper critical field anisotropy ΓH and the magnetic penetration depth anisotropy Γλ of a high-quality FeSe1-xsingle crystal using angular dependent resistivity and torque magnetometry up to 14 T. High quality single crystals of FeSe1-x weresuccessfully grown using KCl-AlCl3 flux method, which shows a sharp superconducting transition at TC ~ 9 K and a high residualresistivity ratio of ~ 25. We found that the anisotropy ΓH near TC is a factor of two larger than found in the poor-quality crystals,indicating anisotropic 3D superconductivity of FeSe1-x. Similar to the 1111-type Fe pnictides, the anisotropies Γλ and ΓH showdistinct temperature dependence; ΓH decreases but Γλ increases with lowering temperature. These behaviors can be attributed tomulti-band superconductivity, but different from the case of MgB2. Our findings suggest that the opposite temperature dependenceof Γλ and ΓH is the common properties of Fe-based superconductors.

Performance of disposable endoscopic forceps according to the manufacturing techniques

권창일,김광일,문종필,윤호,고원진,조주영,홍성표 대한내과학회 2019 The Korean Journal of Internal Medicine Vol.34 No.3

Background/Aims: Recently, to lower the production costs and risk of infection, new disposable biopsy forceps made using simple manufacturing techniques have been introduced. However, the effects of the manufacturing techniques are unclear. The aim of this study was to evaluate which types of biopsy forceps could obtain good-quality specimens according to the manufacturing techniques. Methods: By using an in vitro nitrile glove popping model, we compared the popping ability among eight different disposable biopsy forceps (one pair of biopsy forceps with cups made by a cutting method [cutting forceps], four pairs of biopsy forceps with cups made by a pressing method [pressing forceps], and three pairs of biopsy forceps with cups made using a injection molding method [molding forceps]). Using an in vivo swine model, we compared the penetration depth and quality of specimen among the biopsy forceps. Results: In the in vitro model, the molding forceps provided a significantly higher popping rate than the other forceps (cutting forceps, 25.0%; pressing forceps, 17.5%; and molding forceps, 41.7%; p = 0.006). In the in vivo model, the cutting and pressing forceps did not provide larger specimens, deeper biopsy specimen, and higher specimen adequacy than those obtained using the molding forceps (p = 0.2631, p = 0.5875, and p = 0.2147, respectively). However, the molding forceps showed significantly more common crush artifact than the others (cutting forceps, 0%; pressing forceps, 5.0%; and molding forceps, 43.3%; p = 0.0007). Conclusions: The molding forceps provided lower performance than the cutting and pressing forceps in terms of crush artifact.

Guide-Wire Assisted Endobiliary Forceps Biopsy Sampling

권창일,김태헌,김경아 대한소화기내시경학회 2017 Clinical Endoscopy Vol.50 No.4

Brief report

Bile Flow Phantom Model and Animal Bile Duct Dilation Model for Evaluating Biliary Plastic Stents with Advanced Hydrophilic Coating

권창일,김광일,Seok Jeong,Won Seop Lee,Don Haeng Lee,Kwang Hyun Ko,Sung Pyo Hong,Ki Baik Hahm 거트앤리버 소화기연관학회협의회 2016 Gut and Liver Vol.10 No.4

Background/Aims: The efforts to improve biliary plastic stents (PSs) for decreasing biofilm formation and overcome short patency time have been continued. The aim of this study is to evaluate the effect of advanced hydrophilic coating for patency and biodurability of PS. Methods: Using an in vitro bile flow phantom model, we compared patency between prototype PS with hydrophilic coating (PS+HC) and prototype PS without hydrophilic coating (PS-HC). We performed an analysis of the degree of luminal narrowing by microscopic examination. Using an in vivo swine bile duct dilation model made by endoscopic papillary closure and stent insertion, we evaluated biodurability of hydrophilic coating. Results: In the phantom model, PS+HC showed less biofilm formation and luminal narrowing than PS-HC at 8 weeks (p<0.05). A total of 31 stents were inserted into the dilated bile duct of seven swine models, and 24 stents were successfully retrieved 8 weeks later. There was no statistical difference of stent patency between the polyethylene PS+HC and the polyurethane PS+HC. The biodurability of hydrophilic coating was sustained up to 8 weeks, when assessing the coating layer by scanning electron microscopy examination. Conclusions: Advanced hydrophilic coating technology may extend the patency of PS compared to uncoated PS.

췌장암에 의하여 발생되는 폐쇄의 호전

권창일 대한소화기학회 2019 대한소화기학회지 Vol.74 No.2

Pancreatic cancer is a major cause of cancer-related mortality and morbidity, and its incidence is increasing as the population is aging. On the other hand, significant improvement in the prognosis has not occurred. The absence of early diagnosis means that many patients are diagnosed only when they develop symptoms, such as jaundice, due to a biliary obstruction. The role of endoscopy in multidisciplinary care for patients with pancreatic cancer continues to evolve. Controversy remains regarding the best preoperative biliary drainage in patients with surgically resectable pancreatic head cancer. In general, patients undergoing a surgical resection usually do not require preoperative biliary drainage unless they have cholangitis or receive neoadjuvant chemotherapy. If biliary drainage is performed prior to surgery, the patient’s condition and a multidisciplinary approach should be considered. With the increasing life expectancy of patients with pancreatic cancer, the need for more long-time biliary drainage or pre-operative biliary drainage is also increasing. Strong evidence of endoscopic retrograde cholangiopancreatography (ERCP) as a first-line and essential treatment for biliary decompression has been provided. On the other hand, the use of endoscopic ultrasound-guided biliary drainage as well as percutaneous biliary drainage has been also recommended. During ERCP, self-expandable metal stent could be recommended instead of a plastic stent for the purpose of long stent patency and minimizing stent-induced complications. In this review, several points of view regarding the relief of obstruction in patients with pancreatic cancer, and optimal techniques are being discussed.

Mechanisms of Biliary Plastic Stent Occlusion and Efforts at Prevention

권창일,Glen A. Lehman 대한소화기내시경학회 2016 Clinical Endoscopy Vol.49 No.2

Biliary stenting via endoscopic retrograde cholangiopancreatography has greatly improved the quality of patient care over the last 30 years. Plastic stent occlusion limits the life span of such stents. Attempts to improve plastic stent patency duration have mostly failed. Metal stents (self-expandable metal stents [SEMSs]) have therefore replaced plastic stents, especially for malignant biliary strictures. SEMS are at least 10 times more expensive than plastic stents. In this focused review, we will discuss basic mechanisms of plastic stent occlusion, along with a systematic summary of previous efforts and related studies to improve stent patency and potential new techniques to overcome existing limitations.

Immediate Endoscopic Management of an Intramural Hematoma Developed during Colonoscopy

권창일,김덕환,홍성표 대한소화기내시경학회 2017 Clinical Endoscopy Vol.50 No.5

Brief report

초록집 : 구연 ; 5, 10-MTHFR과 TSER, MTRR A66G 유전적다형성과 간세포암종과의 연관관계

권창일,곽선영,김남근,한진희,고광현,홍성표,황성규,박필원,오도연,임규성,김세현 대한간학회 2005 춘계 학술대회 Vol.11 No.-