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3D Printing
Published in Takahiro Shiota, 3D Echocardiography, 2020
According to the mechanical properties, Yoo et al. used 3D printed models for hands-on surgical training involving 50 surgeons and trainees.17 They concluded that 3D print materials were not completely satisfactory, and the mechanical properties including consistency, elasticity, and tensile strength were different than those of the human myocardium and pericardium. Surgeons found that flexible materials such as TangoPlus were more difficult to sew and were easily torn or cut through as compared with real tissue.17 As stated earlier, silicone appears to be a better material that provides more realistic physical properties close to human tissue.13,17 Chordae tendinae are also very important structures that need to be present in the 3D models for surgical simulations, and some attempts have been made to try to manually incorporate chordae-mimicking strings into the valve, but unfortunately the printing technology is not yet available.
Complications of Fillers and Their Management
Published in Neil S. Sadick, Illustrated Manual of Injectable Fillers, 2020
Silicone is a family of synthetic polymers containing elemental silicone. The viscosity of a silicone filler is dependent upon the polymerization and crosslinkage of its molecules (27). While solid silicone is used as implanted prosthetic devices, the liquid form, silicone oil or gel, is used as an injectable filler (15,27). The FDA approved two forms of liquid silicone for retinal tamponade: AdatoSil (Bausch & Lomb) and Silikon 1000 (Alcon Labs) (28). While the FDA did not approve these products for cosmetic injection to treat rhytides or contour deformities, they have been used off-label as dermal and soft tissue fillers (15,29).
Testicular Cancer
Published in Manit Arya, Taimur T. Shah, Jas S. Kalsi, Herman S. Fernando, Iqbal S. Shergill, Asif Muneer, Hashim U. Ahmed, MCQs for the FRCS(Urol) and Postgraduate Urology Examinations, 2020
Nkwam Nkwam, Chitranjan J. Shukla, David A. Manson-Bahr, Taimur T. Shah, Farooq Khan
Regarding orchidectomy for testicular cancer, which of the following is TRUE?Testicular prosthesis can be inserted without fear of prohibitive infectious complications.Division of the spermatic cord must be taken at the superficial inguinal ring.In cases of symptomatic metastatic disease orchidectomy should precede chemotherapy.Organ-sparing surgery can be performed when tumour volume is less than 50%.Long-term risk of silicone implants is well known.
Implantable medical devices for tendon and ligament repair: a review of patents and commercial products
Published in Expert Review of Medical Devices, 2022
Marco Civera, Ester Devietti Goggia, Matteo De Ros, Vito Burgio, Federica Bergamin, Mariana Rodriguez Reinoso, Cecilia Surace
Another key component is silicone. Silicones are highly versatile materials, suitable for various industries and applications, due to their high elasticity, biocompatibility, easy processability and chemical inertness [64]. They are synthetic polymers, commonly obtained in the form of a linear chain made of polydimethylsiloxane (PDMS). Highly crosslinked silicones or gel-like silicones are nowadays used in medical implants. Silicone elastomers are considered as a material of choice for orthopaedic prostheses and finger joints [64]. Nevertheless, they are insufficiently exploited for use inside the human body, especially for long-term implantation of prostheses, valves etc. The risk of rupture of a silicone implant is associated with degradation processes, as a consequence of multiple causes: autoimmune response due to the microorganisms present in the implantpenetration of lipids into the polymer networkmechanical loading during daily activities
PDMS networks meet barnacles: a complex and often toxic relationship
Published in Biofouling, 2022
Daniel Rittschof, Beatriz Orihuela, Jan Genzer, Kirill Efimenko
Impurities and additives in silicone formulations result in coatings with low but measurable levels of biological toxicity that impair static biological laboratory tests using living model systems such as barnacles. This observation carried out under static conditions was the inspiration for the development of barnacle reattachment assays which enable testing of adhesion even on coatings with high toxicity (Rittschof et al. 2011; Stafslien et al. 2012). Although not formally considered toxic, silicone oils can interact with proteins and alter the structure of protein aggregates (Dixit et al. 2013; Grzybowski et al. 2014; Probst 2020). Silicones change hydrolytic and crosslinking enzyme activity (Rittschof et al. 2011) and impact biological glue curing with a genetic component that can be inherited (Holm et al. 2005).
Drug eluting implants in pharmaceutical development and clinical practice
Published in Expert Opinion on Drug Delivery, 2021
Ashley R. Johnson, Seth P. Forster, David White, Graciela Terife, Michael Lowinger, Ryan S. Teller, Stephanie E. Barrett
Finally, silicones are a family of polymers defined by a long chain of alternating silicon and oxygen atoms [117,118]. The most commonly used silicone in medical devices is poly(dimethylsiloxane) (PDMS), which contains methyl groups as side chains. This polymer has been used in pacemaker leads, mammary prostheses, drainage implants for glaucoma, contact lenses, cochlear implant coatings, transdermal patch adhesives and denture liners. Silicones have found use in these applications due to their beneficial properties, including their biological and chemical inertness, resistance to oxidation, low modulus, low surface adhesion, high oxygen permeability and ability to be formulated in the absence of stabilizers. Unlike the previously described polymers, poly(dimethylsiloxane) is not a thermoplastic. Instead, silicones are extruded at low temperatures and then cured under heat or UV light [119].