• Journal of Korean Neurosurgical Society
• /
• v.65 no.4
• /
• pp.523-530
• /
• 2022

Objective : To evaluate the safety and efficacy of an overlapped stenting-assisted coiling technique in treating vertebral artery dissecting aneurysm (VADA) via Low-profile Visualized Intraluminal Support (LVIS) stent-within-Neuroform EZ stent. Methods : From January 2017 to June 2019, 18 consecutive patients with VADAs (ruptured : unruptured=5 : 13) were treated with the overlapping stents assisted-coiling technique in our center. The overlapping manner was a Neuroform EZ stent being deployed first, followed by LVIS stents placement using the 'shelf' technique. The patients' clinical characteristics, technical feasibility and safety, and immediate and follow-up angiographic results were retrospectively reviewed. Results : Seventeen (94.4%) procedures were technically successful with an exact deployment of the stents and patent parent or perforator arteries. The immediate angiographies after procedure confirmed Raymond class I, II, and III occlusion of VADAs were in 12 (66.7%), two (11.1%), and four cases (22.2%), respectively. Post-procedural complications developed in one patient (5.6%) with minor brainstem infarctions, which resulted from an in-stent thrombosis during the procedure. Angiographic follow-up at 5.7 months (range 3 to 9 months) demonstrated Raymond class I and II occlusion were in all cases (100%). The modified Rankin Scale scores at 21.3 months (range 15 to 42 months) 0-2 in 17 cases (94.4%) and three in one case (5.6%). Conclusion : Overlapping stents via LVIS stent-within-Neuroform EZ stent combined with coiling is safe and effective for patients with VADA in the midterm results.

• Journal of Chest Surgery
• /
• v.25 no.7
• /
• pp.732-735
• /
• 1992

We experienced a case of application of Gianturco Self-Expendable Metal vascular stent for S V.C. syndrome at the postoperative stae of pneumonectomy for Lung cancer[Squamous cell carcinoma, stage IIIa] Placement was performed under fluoroscopic guidance. Clinical problem for patient was resolved satisfactorily Long-term follow-up is required to determine restenosis, complication, and recurrence of cancer, etc.

• Journal of Korean Neurosurgical Society
• /
• v.38 no.2
• /
• pp.132-135
• /
• 2005

We report two cases of patients with ruptured vertebral artery dissecting aneurysms that were treated using double overlapping stent placement. Angiography performed immediately after the procedure revealed a significant reduction of aneurysmal filling due to the intraaneurysmal thorombosis. In one case, complete disappearance of the lesion was observed after seven days and in the another one, the size of previous aneurysm sac was decreased on 7th post-procedure day. The reduced stent porosity caused by the overlapping stents, which result in significant hemodynamic changes inside aneurysmal sac, may accelerate intraanuerysmal thromobosis and may be helpful in achieving a more rapid complete occlusion of aneurysm. This double stent method may represent a therapeutic alternatives for dissecting vertebral artery aneurysm in which conventional endovascular techniques or stent supported coil embolization is not considered feasible and surgical treatment is contraindicated.

• Korean Journal of Bronchoesophagology
• /
• v.2 no.2
• /
• pp.213-221
• /
• 1996

To evaluate the clinical effectiveness of expandable metallic stents, the stents were implanted under endoscopic guidance with local anesthesia or general anesthesia for maintenance of the constructed subglottic space of trachea. The nine patients with respiration difficulty were subjected for expandable stents. The stenosis of upper airway were due to the framework problem of subglottic trachea and tracheostoma after total laryngectomy. Stents were constructed of 0.4 m stainless steel win in a zigzag configuration of 8 bends. A single stent was 20 m in diameter when fully expanded and 20 mm long. The stents were placed accurately to the stenotic site and followed to the 5 month after stent placement. The stenotic area became narrowed with overgrowing of granuloma in all patients and the metallic stents were removed and the stenotic area reconstructed surgically. As conclusion, this technique for the treatment of the subglottic trachea showed simple and safe, but highly recurred due to overgrowing of granuloma. We suggest that the expandable metallic stent is not encouraging in this study.

• Proceedings of the KSME Conference
• /
• 2003.04a
• /
• pp.485-490
• /
• 2003

In this paper, a nonlinear finite-element method was employed to analyze mechanical behaviors of the balloon-expandable stent. Beyond safety considerations, this type of analysis provides mechanical properties that are often difficult to obtain by experiments. Mechanical properties of the stent expansion pressure, radial recoil, longitudinal recoil and foreshortening were studied using commercial FEM code, ANSYS. As a result, the pressure necessary to expand the stent up to a diameter of 3mm was 7.6atm, longitudinal recoil, radial recoil and foreshortening were -0.388%, 2.87% and 4.07% respectively. In conclusion, a finite element model used in this study could help in designing new stents or analyzing actual stents.

• Journal of Korean Neurosurgical Society
• /
• v.52 no.6
• /
• pp.551-554
• /
• 2012

Alternative to carotid endarterectomy, carotid artery stenting (CAS) can be performed for symptomatic severe stenosis of internal carotid artery, especially for high-risk patients. Among several complications after CAS, subacute in-stent thrombosis is rare but important, because patient's condition can deteriorate rapidly. Subacute in-stent thrombosis with carotid artery occlusion can be managed by superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis. We report two cases of STA-MCA anastomosis for internal carotid artery occlusion by subacute in-stent thrombosis after CAS.

• Journal of Magnetics
• /
• v.22 no.1
• /
• pp.162-167
• /
• 2017

Magnetic spiral-type microrobots, which are driven by a rotating magnetic field, have excellent locomotive abilities, whereas their medical applications are limited in the terms of function, such as the ability to drill in blood vessels. In this study, we propose a new robot with superior applications using a magnetic spiral-type machine. The proposed robot can be applied to stent transportation and installation without a catheter. In particular, the robot can be applied to the cardiovascular system, cerebrovascular disease, and nonvascular stent applications depending on the robot size. The robot consists of two independent spiral-type machines and four magnets in total. We controlled directions of thrust force of the two machines, respectively, for active locomotion with a task. We conducted a preliminary validation of the proposed robot for stent transportation and installation through experimental analyses.

• Journal of Digestive Cancer Research
• /
• v.10 no.2
• /
• pp.92-98
• /
• 2022

Self-expandable metal stent (SEMS) is effective for biliary drainage, especially in pancreaticobiliary cancer. The mechanical properties, material, and design of SEMS are important in preventing recurrent biliary obstruction and complication. Radial and chronic expansion forces play roles in preventing stent migration and collapse. Complications, such as stent impaction, cholecystitis, and pancreatitis, were related to the axial force. The nickel-titanium alloy shows more flexibility, conformability, and optimal axial force compared to previously used stainless steel. Additionally, the stent structure affected the mechanical properties of SEMS. Therefore, understanding the mechanical properties, material, and design of SEMS will provide the best outcome for biliary drainage, as well as better SEMS development.

• Journal of Medicine and Life Science
• /
• v.20 no.3
• /
• pp.131-134
• /
• 2023

Here, we present a case of a 56-year-old man with acute myocardial infarction. The patient underwent percutaneous coronary intervention (PCI) at the left main bifurcation and mid-left anterior descending artery using drugeluting stents. Four months after the PCI, the patient was readmitted for cardiac arrest. Coronary angiography (CAG) revealed stent thrombosis in the left main-to-proximal left anterior descending artery and in-stent restenosis in the left main-to-proximal left circumflex artery. We performed balloon angioplasty at the left main to mid-left anterior descending artery and left main to proximal left circumflex artery stents; subsequently, blood flow was fully restored. However, contrast agent extravasation was observed outside the mid-portion of the left main artery to the proximal left anterior descending artery stent, indicating the presence of a coronary artery aneurysm (CAA) outside the stent. After guideline-directed medical therapy with dual antiplatelet agents and high-intensity statins, follow-up CAG revealed near-resolution of the CAA, absence of stenotic lesions, and good blood flow.

• Journal of the Korean Society for Precision Engineering
• /
• v.29 no.1
• /
• pp.103-108
• /
• 2012

Restenosis symptom, which is well known as a problem of stents, is due to the recoil and expansion pressure depending on shapes of stent. In order to reduce the effect of recoil problem, study on pattern and shape for the stent is required and the expansion pressure and recoil should be evaluated. This paper aims at evaluating mechanical characteristics of stent used in surgery for vessel stenosis. The expansion process of coronary artery stent in vessel for two models including the Cypher$^{(R)}$ from Johnson & Johnson$^{TM}$ and a suggested model were simulated using the Finite Element Analysis. Comparison of the directional recoil simulation results was made. The issues in the deformed shape of vessel and recoil of Cypher$^{(R)}$ were partially resolved in the suggested model. Therefore, the shape design suggested in this paper was able to reduce the restenosis symptom.