LEVERKUSEN -- The level of vision-impairing retinal disease being diagnosed by eye specialists is growing. Most cases are due to macular degeneration, or AMD for short, which is particularly prevalent among the older generation. Alcon Grieshaber AG, a leading medical technology manufacturer based in Schaffhausen, Switzerland, has developed a new generation of surgical instruments to help combat this problem. The Grieshaber Revolution™ DSP micro forceps and scissors have the advantage over similar commercial instruments that they can be freely rotated while being used. As a result, surgeons no longer need to hold the instrument at a certain angle in order to grasp or cut. This innovative and extremely helpful function is enabled in part by a plastic basket of thin-walled ribs that forms part of the instrument corpus. By pressing in on the basket with his fingers, a hinge in each of the ribs enables the surgeon to activate a sliding mechanism that in turn actuates the forceps or scissors at the tip of the instrument. The design of the thin-walled rib basket proved a tough nut to crack. "What was needed was an engineering material with outstanding mechanical strength, stiffness and toughness," explains Markus Krieter, a medical technology expert in the Polycarbonates Business Unit of Bayer MaterialScience AG. "Our polycarbonate Makrolon® 2458, which is approved for medical applications, fulfilled all these requirements. Its excellent dimensional stability also ensures that this delicate injection molded component can be easily demolded and that the forceps or scissors work reliably."
In total, eight of the single-use operating instrument's individual components are made of Makrolon®. The manufacturer of these parts is Gebr. Renggli AG in Schaffhausen, an internationally renowned expert in precision injection molding and mold construction. The parts are manufactured using a laminar flow process, then cleaned and finished in a cleanroom. The actual instruments themselves are assembled in a cleanroom at Alcon Grieshaber.
A highlight of the instrument range is a version with luminous forceps. Light travels along glass fibers to the tip of the instrument where it provides illumination precisely where needed at the operation site. The diminutive forceps that measure only a few millimeters in length and width are also injection molded and are made from Makrolon® Rx 2530. "Alongside its excellent mechanical properties, the good photoconductivity of our highly transparent polycarbonate makes it ideal," comments Krieter.
Gebr. Renggli AG has been using Makrolon® Rx 2530 and 2458 in a wide range of plastic medical components for a number of years. The reason for this is that the polycarbonate can be sterilized either with superheated steam at a temperature of 121 °C, with ethylene oxide, or with high-energy radiation such as gamma and electron beams. As with all other thermoplastics for medical technology, Bayer MaterialScience also guarantees the long-term availability of these materials, ensures reliable delivery and provides binding assurances that the relevant formulations will remain constant. Moreover, all materials supplied for medical technology meet the requirements of the American standard US-Pharmacopeia, Class VI, relating to the biological compatibility of plastics. The same is true for the internationally applicable standard ISO 10993-1 covering the biocompatibility of plastics that remain in contact with body fluids and tissue for up to 30 days.
With sales of EUR 10.7 billion in 2005, Bayer MaterialScience AG is one of the world's largest polymer manufacturers. Its main fields of activity are the production of high-tech polymer materials and the development of innovative solutions for products used in many areas of everyday life. The main consumer sectors are the automotive, electrical/electronics, construction, sports and leisure industries. Bayer MaterialScience has production facilities at 40 sites around the world and a workforce of approx. 18,800. Bayer MaterialScience is part of the Bayer Group.
