The clinical impact of tissue engineering.
Four generations of surgical implant development will be discernible by the end of this century: 1. A first generation of industrial materials (materials originally fabricated for industrial applications other than medical devices) in ad hoc devices that had little impact on the practices of medicine and surgery. 2. Industrial materials in bioengineered devices to effect the replacement of damaged structures. While these devices returned function to millions of people, formed the basis for a new industry, and forever changed the practices of medicine and surgery, their components have proved less than ideal. 3. Bioengineered materials fabricated specifically for medical device use-that are meant to be bioactive rather than inert-and that promise to improve the performance of some devices. 4. Tissue engineering, which while yet to be utilized in widely marketed devices, promises to usher in revolutionary changes at least as dramatic as those caused by the second-generation bioengineered devices. Fourth-generation technologies will focus on repair and regeneration rather than reconstruction and replacement; they will emphasize therapeutic prevention of disease and early intervention. The minimally invasive nature of these new technologies will cause medical practitioners to partially displace surgeons, and fewer hospital beds and operating rooms will be needed. While such technology may involve high startup costs, in the long run the total costs of care should decline because of more efficient, less expensive procedures.
Alexander
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Department of Bioengineering, Hospital for Joint Diseases, New York, New York 10003.