Johnson & Johnson has continued to investigate their metal-on-metal implants, which were recalled in 2010 due to some patients reactions to metal debris generated during articulation. In a Reuter's report today, J&J had fourth quarter charges of $800 million associated with medical costs related to the recall.
Temporary or permanent implants often contain a radiopacifier, which is a material with a higher electron density contrast compared to the surrounding material so that it absorbs X-ray energy. In an X-ray, a radiopacifier appears as a bright section, as shown in the catheter above (the internal wire is a radiopacifier). Radiopacifiers are often made of metals such as gold, tungston, or powders such as zirconium oxide, barium sulphate and bismuth. When considering the design of a new medical device, manufacturers will need to assess the radiocontrast of the device so that the medical practitioner can see the device during implantation, in the case of catheters, guidewires, and other temporary devices with the use of fluoroscopes, or after permanent implantation, in the case of hip and knee replacements, stents, heart valves, and other permanent devices.
ASTM F640 "Standard Test Methods for Determining the Radiopacity for Medical Use" describes test methods for quantitative assessment of the contrast a radiopacifier has in a medical device, for either permanent implantation or temporary. In this method, the device is placed into an X-ray imaging system and imaged using standard times, voltages, and currents used for the X-ray diagnosis of humans. For two of the test methods, body mimics can be used, which may be animal, cadaver, or synthetic components that replicate the portion of the body where the device is to be placed. From the X-ray image of the device, a densitometry system is used to measure the optical density difference between the sample radiopacifier and the background.
CPG performs ASTM F640 using our custom densitometry system. Please contact us for your testing needs.
Synthetic tissue constructs have been around since the 1970's, when Dr.'s Yannas and Burke created an artificial skin from collagen and silicone rubber. This membrane, termed Silastic, was designed to mimic the properties of skin, to help generate new skin in burn victims.
Researchers from the Medical School Hannover (Germany) are trying to replicate human skin through the use of harvested spider silk. L'Oreal and Mattek have design synthetic skin models (EpiDerm from Mattek and EpiSkin and SkinEthic RHE) based on human skin cells.
CPG scientists have developed a multi-layer tissue model to mimic the outer epidermis, fat, muscle, and underlying fascia layer in the skin using CPG's proprietary hydrogel technology. The model is designed to be used for incision and suture training. Contact CPG for more information.
Cambridge Polymer Group and Massachusetts General Hospital have co-developed novel, highly crosslinked ultra high molecular weight polyethylenes that incorporate vitamin E and are suitable for hip, knee, shoulder and spine arthroplasty applications. These technologies, generically termed CIMA, E-CIMA and Reservoir Vitamin E, are available for license.
E-CIMA
E-CIMA is a formulation containing Vitamin E throughout the material. Following blending and consolidation, the sample is subjected to ionizing radiation, which forms crosslinks in the material. The material is then deformed at a temperature below the melting point to quench residual free radicals. An annealing step returns the sample to its original shape, after which it is ready for machining into an implant. E-CIMA has wear properties similar to remelted, highly crosslinked UHMWPE, yet has the improved mechanical properties approaching virgin UHMWPE. Coupled with this is the oxidative resistance of Vitamin E.
This patented material is available for licensing. One licensee, Corin Group, published on E-CIMA properties at the 2011 Orthopedic Research Society meeting.
(2/9/2012 update): Corin has announced that they received FDA clearance on E-CIMA (product name eCiMA).
CIMA
CIMA is similar to E-CIMA, but does not incorporate Vitamin E into the UHMWPE matrix. This material provides good wear, good mechanical properties, and improved oxidation stability over annealed highly crosslinked UHMWPE.
Reservoir Vitamin E
The Reservoir Vitamin E is a surface crosslinked UHMWPE that contains Vitamin E in specific locations, allow targeted crosslinking in regions where wear rates must be control, yet high mechanical properties in regions where locking mechanisms are located. This material has excellent applications for re-surfacing or thin liners in orthopedics, and is available for licensing.
Contact Cambridge Polymer Group for information about properties, licensing and regulatory approval.
CPG will have an exhibit at the upcoming annual meeting of the Orthopedic Research Society in San Francisco, CA, from February 4th to February 7th. This conference brings researchers, medical device manufacturers, surgeons, and regulatory agency representatives together to discuss the latest technologies, practices, and clinical outcomes in the area of orthopedic surgery, including hip, knee, spine, shoulder, ankle, and other joint spaces. Come visit us to learn about the latest work we are doing in this growing area.
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When marketing a new product, differentiating your product from your competition can be a nuanced activity, depending on the nature of the product. In more tightly regulated markets, customers may require side-by-side comparisons of their existing approved and validated products with your new offering, to ensure that it has the same or better properties. As they have usually gone through some time and expense to validate the product, be it a raw material or finished good, and they bear a risk in changing, you need to demonstrate that the risk is worth it in terms of cost-savings or improved performance.
At Cambridge Polymer Group, we often assemble and perform a set of standard or customized tests that helps the client highlight the key performance traits of their product, while also demonstrating that the root level performance characteristics meet or exceed what their customer is currently using. Whenever possible, we use ASTM standard tests in the relevant industries to assemble a single page of testing results that your sales group can provide to customers. We perform these tests in our ISO-certified laboratory, so you can be assured of the quality and un-biased nature of our results.
The U.S. Senate has introduced a bill that allows the FDA to require medical device companies to collect and track data on the clinical performance of their marketed devices, such as hip and knee replacements. This action is in part due to the on-going reported issues of metal-on-metal hip implants failing due to metal ion sensitivity, which some studies have shown lead to the formation of pseudo-tumors. Advocates for this data collection suggest that the information will be useful for the on-going 510(k) regulatory approval process for new devices that have similar characteristics to already marketed devices, for-going the need for clinical studies necessary in a full PMA process.