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https://www.readbyqxmd.com/read/28190716/five-year-outcomes-of-the-pythagoras-u-s-clinical-trial-of-the-aorfix-endograft-for-endovascular-aneurysm-repair-in-patients-with-highly-angulated-aortic-necks
#1
Mahmoud B Malas, Caitlin W Hicks, William D Jordan, Kim J Hodgson, Joseph L Mills, Michel S Makaroun, Michael Belkin, Mark F Fillinger
OBJECTIVE: Early and midterm outcomes of the Prospective Aneurysm Trial: High Angle Aorfix Bifurcated Stent Graft (PYTHAGORAS) trial in patients with highly angulated aortic necks (≥60 degrees) have already been published and shown comparable outcomes to other endografts in normal anatomy. Herein, we present the long-term outcomes of the PYTHAGORAS trial of Aorfix (Lombard Medical, Irvine, Calif) for patients with highly angulated aortic neck anatomy. METHODS: The Aorfix endograft is a highly conformable nitinol/polyester device designed for transrenal fixation...
February 9, 2017: Journal of Vascular Surgery
https://www.readbyqxmd.com/read/28175977/development-and-evaluation-of-a-novel-curved-biopsy-device-for-ct-guided-biopsy-of-lesions-unreachable-using-standard-straight-needle-trajectories
#2
Maximilian Franz Schulze-Hagen, Jochen Pfeffer, Markus Zimmermann, Martin Liebl, Saskia Freifrau von Stillfried, Christiane Kuhl, Philipp Bruners, Peter Isfort
PURPOSE: To evaluate the feasibility of a novel curved CT-guided biopsy needle prototype with shape memory to access otherwise not accessible biopsy targets. METHODS AND MATERIALS: A biopsy needle curved by 90° with specific radius was designed. It was manufactured using nitinol to acquire shape memory, encased in a straight guiding trocar to be driven out for access of otherwise inaccessible targets. Fifty CT-guided punctures were conducted in a biopsy phantom and 10 CT-guided punctures in a swine corpse...
February 7, 2017: Cardiovascular and Interventional Radiology
https://www.readbyqxmd.com/read/28168366/evolution-of-patency-rates-of-self-expandable-bare-metal-stents-for-endovascular-treatment-of-femoro-popliteal-arterial-occlusive-disease-does-stent-design-matter
#3
Karla Maria Treitl, Benedikt Woerner, Regina Schinner, Michael Czihal, Susan Notohamiprodjo, Ulrich Hoffmann, Marcus Treitl
OBJECTIVE: To analyse the patency rates of femoro-popliteal stenting with different self-expandable Nitinol stent-designs. METHODS: Two hundred and twenty-two patients (142 (64%) male; age 72.4 ± 11.6 years) with symptomatic femoro-popliteal peripheral arterial occlusive disease (PAOD) underwent percutaneous transluminal angioplasty (PTA) and stenting with three different Nitinol stents (interwoven IW: n = 70; closed-cell CC: n = 85; open-cell OC: n = 67)...
February 6, 2017: European Radiology
https://www.readbyqxmd.com/read/28162939/fatigue-behaviour-of-niti-shape-memory-alloy-scaffolds-produced-by-slm-a-unit-cell-design-comparison
#4
M Speirs, B Van Hooreweder, J Van Humbeeck, J-P Kruth
Selective laser melting (SLM) is an additive manufacturing technique able to produce complex functional parts via successively melting layers of metal powder. This process grants the freedom to design highly complex scaffold components to allow bone ingrowth and aid mechanical anchorage. This paper investigates the compression fatigue behaviour of three different unit cells (octahedron, cellular gyroid and sheet gyroid) of SLM nitinol scaffolds. It was found that triply periodic minimal surfaces display superior static mechanical properties in comparison to conventional octahedron beam lattice structures at identical volume fractions...
January 12, 2017: Journal of the Mechanical Behavior of Biomedical Materials
https://www.readbyqxmd.com/read/28159224/salivary-levels-of-nickel-chromium-iron-and-copper-in-patients-treated-with-metal-or-esthetic-fixed-orthodontic-appliances-a-retrospective-cohort-study
#5
Renata Bandeira Lages, Enrico Coser Bridi, Carlos Alberto Pérez, Roberta Tarkany Basting
The purpose of this retrospective cohort study was to measure the salivary levels of nickel (Ni), chromium (Cr), iron (Fe) and copper (Cu) released from metal and esthetic fixed orthodontic appliances. Ninety patients were divided into three groups (n=30): control (those who had never undergone orthodontic treatment), metal appliance (stainless steel brackets and bands, and nitinol archwires) and esthetic appliance (polycarbonate brackets and tubes, and rhodium-coated nitinol archwires). Patients undergoing orthodontic treatment had used their appliances for periods between one and six months...
March 2017: Journal of Trace Elements in Medicine and Biology
https://www.readbyqxmd.com/read/28152273/effects-of-tissue-digestion-solutions-on-surface-properties-of-nitinol-stents
#6
Stacey J L Sullivan, Philip Stafford, Elon Malkin, Maureen L Dreher, Srinidhi Nagaraja
Analysis of explanted medical implants can provide a wealth of knowledge about device safety and performance. However, the quality of information may be compromised if the methods used to clean tissue from the device disturb the retrieved condition. Common solutions used to digest tissue may adversely affect the surface of the device and its severity can be material and processing dependent. In this study, two groups of stents made from the same material (Nitinol) were shape set in a salt pot (SP) or further processed by mechanical polishing (MP) and then immersed in one of three tissue digestion solutions (TDS): nitric acid (HNO3 ), sodium hydroxide (NaOH), or papain enzyme (papain)...
February 2, 2017: Journal of Biomedical Materials Research. Part B, Applied Biomaterials
https://www.readbyqxmd.com/read/28151035/long-term-efficacy-and-safety-of-a-nitinol-closure-clip-system-for-anal-fistula-treatment
#7
Sebastian Dango, Fillimon Antonakis, Dirk Schrader, Arkadiy Radzikhovskiy, Michael B Ghadimi, Rudolf Hesterberg
INTRODUCTION: Treatment failure of anal fistula results in high re-occurrence rate. MATERIAL AND METHODS: Efficacy and safety of a nitinol closure clip system (bear-claw clip) were evaluated for anal fistulae treatment in a 36-month long-term follow-up study. RESULTS: Twenty-two patients were included. No patient had been treated with a bear-claw clip system before. All patients were fully continent before treatment. Follow-up time was 36 months (range 19-48 months)...
February 2, 2017: Minimally Invasive Therapy & Allied Technologies: MITAT
https://www.readbyqxmd.com/read/28150055/numerical-modeling-of-nitinol-stent-oversizing-in-arteries-with-clinically-relevant-levels-of-peripheral-arterial-disease-the-influence-of-plaque-type-on-the-outcomes-of-endovascular-therapy
#8
Can Gökgöl, Nicolas Diehm, Philippe Büchler
Oversizing of the Nitinol stents in the femoro-popliteal arterial tract is commonly performed by clinicians and further encouraged by stent manufacturers. However, in spite of the procedure's supposed benefits of strong wall apposition and increased luminal gain, its effects on the mechanical behavior of arteries with peripheral arterial disease are not fully clear. In this study, finite element (FE) analyses of endovascular revascularization of an idealized artery with 70% stenosis and three different plaque types have been performed to examine the influence of Nitinol stent oversizing on the arterial stresses and acute lumen gain...
February 1, 2017: Annals of Biomedical Engineering
https://www.readbyqxmd.com/read/28145041/first-in-human-experience-of-a-new-self-expandable-percutaneous-pulmonary-valve-implantation-using-knitted-nitinol-wire-and-tri-leaflet-porcine-pericardial-valve-in-the-native-right-ventricular-outflow-tract
#9
Gi Beom Kim, Bo Sang Kwon, Hong Gook Lim
Balloon-expandable percutaneous pulmonary valve systems using the Melody and Edwards SAPIEN transcatheter heart valves have been increasingly used instead of surgically implantable pulmonary valves. However, limited patients with right ventricular outflow tract (RVOT) lesions are suitable candidates for percutaneous pulmonary valve implantation (PPVI) using these systems after surgical correction of tetralogy of Fallot. Therefore, larger self-expandable valved-stents are being developed for native RVOT lesions...
February 1, 2017: Catheterization and Cardiovascular Interventions
https://www.readbyqxmd.com/read/28139202/postoperative-analysis-of-the-mechanical-interaction-between-stent-and-host-tissue-in-patients-after-transcatheter-aortic-valve-implantation
#10
Raoul Hopf, Simon H Sündermann, Silvia Born, Carlos E Ruiz, Nicolas M Van Mieghem, Peter P de Jaegere, Francesco Maisano, Volkmar Falk, Edoardo Mazza
The analysis is based on a finite element procedure to extract the contact forces between an implanted Nitinol stent and the surrounding host tissue using postoperative CT images. The methodology was applied for patients (N=46) which have undergone a TAVI procedure with the Medtronic CoreValve Revalving System (MCRS) to obtain corresponding deformation and force maps. The postoperative CT data were recorded for each patient in both systolic and diastolic phase of the heart cycle. Scalar parameters were defined, which map deformed geometry and contact force field to mechanically relevant quantities: radial dilatation, radial shape distortion, non-convex points, mean force, a force deviation measure and a pressure equivalent...
December 30, 2016: Journal of Biomechanics
https://www.readbyqxmd.com/read/28117211/assessment-of-vascular-stent-heating-with-repetitive-transcranial-magnetic-stimulation
#11
Nicole Varnerin, David Mirando, Kelsey A Potter-Baker, Jesus Cardenas, David A Cunningham, Vishwanath Sankarasubramanian, Erik Beall, Ela B Plow
OBJECTIVE: A high proportion of patients with stroke do not qualify for repetitive transcranial magnetic stimulation (rTMS) clinical studies due to the presence of metallic stents. The ultimate concern is that any metal could become heated due to eddy currents. However, to date, no clinical safety data are available regarding the risk of metallic stents heating with rTMS. METHODS: We tested the safety of common rTMS protocols (1 Hz and 10 Hz) with stents used commonly in stroke, nitinol and elgiloy...
January 20, 2017: Journal of Stroke and Cerebrovascular Diseases: the Official Journal of National Stroke Association
https://www.readbyqxmd.com/read/28104422/tipless-nitinol-stone-baskets-comparison-of-penetration-force-radial-dilation-force-opening-dynamics-and-deflection
#12
Nishant Patel, Arash Akhavein, Bryan Hinck, Rajat Jain, Manoj Monga
OBJECTIVE: To evaluate 5 commercially available tipless nitinol baskets (2.2F) in 4performance factors: penetration force, radial dilation force, opening dynamics and deflection limitation. MATERIAL AND METHODS: The 2.2F Coloplast Dormia No-Tip®, 1.5F Sacred Heart Medical Halo®, 2.2F Cook NCircle Nitinol Tipless Stone Extractor ®, 1.9F Bard SkyLite Tipless Nitinol Basket® and the 1.9F Boston Scientific Zero TipTM baskets were tested for penetration force (safety metric), radial dilation force (functional metric for ureteral calculi), and opening/closing dynamics...
January 16, 2017: Urology
https://www.readbyqxmd.com/read/28095767/in-vivo-quantification-of-the-deformations-of-the-femoropopliteal-segment
#13
Can Gökgöl, Steffen Schumann, Nicolas Diehm, Guoyan Zheng, Philippe Büchler
PURPOSE: To quantify the deformations of the femoropopliteal (FP) segment in patients undergoing endovascular revascularization and to compare the posttreatment deformations caused by primary nitinol stent implantation to those produced by percutaneous transluminal angioplasty (PTA). METHODS: Thirty-five patients (mean age 69±10 years; 20 men) scheduled for endovascular therapy were recruited for the study. During endovascular interventions, angiographic images were acquired with the legs straight and with a hip/knee flexion of 20°/70°...
February 2017: Journal of Endovascular Therapy
https://www.readbyqxmd.com/read/28070228/design-fabrication-and-testing-of-a-needle-sized-wrist-for-surgical-instruments
#14
Philip J Swaney, Peter A York, Hunter B Gilbert, Jessica Burgner-Kahrs, Robert J Webster
This paper presents a miniature wrist that can be integrated into needle-sized surgical instruments. The wrist consists of a nitinol tube with asymmetric cutouts that is actuated by a single tendon to provide high distal curvature. We derive and experimentally validate kinematic and static models for the wrist and describe several prototype wrists, illustrating the straightforward fabrication and scalability of the design. We experimentally investigate fatigue life, the concept of tip-first bending, and practical use of the wrist with a concentric tube robot in an endonasal surgical scenario...
March 2017: Journal of Medical Devices
https://www.readbyqxmd.com/read/28047715/we-de-201-08-multi-source-rotating-shield-brachytherapy-apparatus-for-prostate-cancer
#15
H Dadkhah, X Wu, Y Kim, R Flynn
PURPOSE: To introduce a novel multi-source rotating shield brachytherapy (RSBT) apparatus for the precise simultaneous angular and linear positioning of all partially-shielded 153Gd radiation sources in interstitial needles for treating prostate cancer. The mechanism is designed to lower the detrimental dose to healthy tissues, the urethra in particular, relative to conventional high-dose-rate brachytherapy (HDR-BT) techniques. METHODS: Following needle implantation, the delivery system is docked to the patient template...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28046531/tu-h-206-08-quantitative-impact-of-biliary-stent-artefacts-on-mr-images
#16
O Gurney-Champion, T Bruins Slot, E Lens, A van der Horst, R Klaassen, H van Laarhoven, J van Hooft, A Nederveen, A Bel
PURPOSE: Biliary stents may cause artifacts in MR-images. These artifacts are caused by differences in susceptibility (artifact-1), eddy currents during read-out (artifact-2) and eddy currents due to the excitation pulse (artifact-3), which all are MRI sequence-dependent. In this study, we investigated and quantified the magnitude of these artifacts as a function of the distance from biliary stents, using a sequence-independent approach where possible. METHODS: Eight phantoms were made containing different commercial biliary stents made of nitinol, platinol, stainless steel or polyethylene...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28031841/long-term-outcome-of-nitinol-stenting-to-treat-asphyxia-caused-by-postpneumonectomy-syndrome
#17
Jiro Abe, Toru Hasumi, Ryota Tanaka, Yasuki Saito, Keishi Kanma, Satomi Takahashi
The long-term outcome of nitinol stents introduced into a patient with postpneumonectomy syndrome is described. Postpneumonectomy syndrome is a rare but crucial complication after pneumonectomy characterized by severe dyspnoea and recurrent airway infection caused by compression of the main bronchus. Surgical correction of mediastinal displacement and endobronchial stent placement are two major treatments for this complication; however, endobronchial stenting may be limited to those who are not suitable for operative procedures because long-term management is difficult in terms of controlling airway infections...
January 2017: Respirology Case Reports
https://www.readbyqxmd.com/read/28031646/angioplasty-and-stenting-of-distal-anastomotic-stenosis-of-femoropopliteal-bypass-graft-using-helical-interwoven-nitinol-stents
#18
Yiu Che Chan, Stephen Cheng
Minimally invasive endovascular options of angioplasty and stenting can be used to treat distal anastomotic stenoses in lower limb bypass grafts, but stents near the knee joint may fracture. The nitinol helical interwoven structure of the Supera stents (IDEV Technologies Inc., Houston, TX) has improved flexibility and kink resistance. We report a patient who received salvage angioplasty and Supera stenting of the distal anastomosis of femoropopliteal bypass grafts with good mid-term results. Considering the high radial strength and fracture resistance, these Supera stents may be a good treatment option in salvaging failing bypass grafts...
December 2016: International Journal of Angiology: Official Publication of the International College of Angiology, Inc
https://www.readbyqxmd.com/read/28028692/in-vitro-hydrodynamic-assessment-of-a-new-transcatheter-heart-valve-concept-the-triskele
#19
Benyamin Rahmani, Spyros Tzamtzis, Rose Sheridan, Michael J Mullen, John Yap, Alexander M Seifalian, Gaetano Burriesci
This study presents the in vitro hydrodynamic assessment of the TRISKELE, a new system suitable for transcatheter aortic valve implantation (TAVI), aiming to mitigate the procedural challenges experienced with current technologies. The TRISKELE valve comprises three polymeric leaflet and an adaptive sealing cuff, supported by a novel fully retrievable self-expanding nitinol wire frame. Valve prototypes were manufactured in three sizes of 23, 26, and 29 mm by automated dip-coating of a biostable polymer, and tested in a hydrodynamic bench setup in mock aortic roots of 21, 23, 25, and 27 mm annulus, and compared to two reference valves suitable for equivalent implantation ranges: Edwards SAPIEN XT and Medtronic CoreValve...
December 27, 2016: Journal of Cardiovascular Translational Research
https://www.readbyqxmd.com/read/28024627/fretting-corrosion-behavior-of-nitinol-spinal-rods-in-conjunction-with-titanium-pedicle-screws
#20
Elena Lukina, Mikhail Kollerov, Jay Meswania, Alla Khon, Pavel Panin, Gordon W Blunn
Untypical corrosion damage including erosions combined with the build-up of titanium oxide as a corrosion product on the surface of explanted Nitinol spinal rods in the areas where it was in contact with titanium pedicle screw head is reported. It was suggested that Nitinol rods might have inferior fretting corrosion resistance compared with that made of titanium or CoCr. Fretting corrosion of Nitinol spinal rods with titanium (Ti6Al4V) pedicle screws were tested in-vitro by conducting a series of potentiostatic measurements of the peak-to-peak values of fretting corrosion current under bending in a 10% solution of calf serum in PBS...
March 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
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