While bioresorbable materials have been getting a great deal of attention in the medical arena during the last 10 to 15 years, relatively few have been adopted for use in marketable products. That may change, as production efficiencies and economies of scale improve. Materials expert Len Czuba, who heads product design and development firm Czuba Enterprises, explains.
PlasticsToday: What are the primary bioresorbable materials in use today and what are some typical applications? What are the benefits for the patient?
Len Czuba: There are about a dozen materials commonly considered as “bioresorbable” but, of these, only a few are commonly used in medical device applications. Most resorbable medical devices are made from glycolide-lactide polymers and copolymers, polycaprolactone, polydioxanone and polytrimethylene carbonate. Applications include surgical sutures, orthopedic pins, screws, rods and plates, cardiovascular stents, hernia repair and reinforcement meshes and tissue anchors. In every case just mentioned, the medical device is needed to help the recipient recover from an injury or to allow healing of a suture, tear, break or other deficiency in the tissue or to allow healing of a reopened blood vessel or repositioned tissue.
It stands to reason that after the bone or blood vessel or sutured tissue is healed, the medical device providing the support needed during that healing is no longer needed. If it were to remain in place, in the long term, the body would begin to react to it as it would to any other foreign object. A dramatic example is cardiovascular stents made from nitinol metal. They provide life-saving intervention into otherwise blocked blood vessels allowing immediate return of normal blood flow, usually to the heart. But after the blood vessel “heals” in the new opened position, the metal stent becomes a foreign body that can lead to restenosis, or re-formation of blood clots, unless the patient is otherwise treated. The resorbable stents will be eliminated and not lead to complications typical with metal stents. Similar benefits are found with resorbables in orthopedic applications, surgical repairs and tissue reinforcements and anchors.
|Len Czuba will discuss the sourcing and qualification of materials for implantable medical devices during a conference session at MD&M West, the world's largest annual medtech event coming to Anaheim, CA, next month. He will also be leading an Innovation Tour devoted to breakthrough materials exhibited on the show floor. MD&M West is co-located with PLASTEC West at the Anaheim Convention Center on Feb. 7 to 9, 2017. For more information and to register to attend, go to the PLASTEC West website.|
PlasticsToday: What are some of the challenges associated with sourcing the materials and processing them, especially when it comes to molding the parts?
Czuba: I believe that there are two or three major challenges related to the use of bioresorbables for implantable medical devices.
First, recognize that in most cases, the resorbable device is intended to be placed in the patient to assist in the healing process, which can be weeks to months. After the healing period, there is then the extended time that it takes for the implanted device to be resorbed and eliminated from the tissue and the body which can be at least double the healing time. So these devices are all considered long-term implants. This means that besides selecting materials that are shown to be safe and effective, these materials must be sourced from suppliers that are willing to supply materials for long-term implantable medical device applications. My experience is that there is still quite a bit of reluctance from suppliers to