Three mechanisms have been described which explain various observed interactions between polyurethane chemistry and body chemistry. These include calcification, environmental stress cracking, and chain scission. Each may result in implant device failure, and each appears to involve metal ion complexation as a key parameter. Continued expansion of polyurethane into implantable product applications will require further clarification of the effect of each of these interactions on long-term product performance. It is believed that design considerations and polymer modifications will help control the effects of each of the interactions and will result in new and improved polyurethane implant products.
Boretos, J.W. , D.E. Detmer and J.H. Donachy."Segmented Polyurethanes: a Polyether Polymer. II. Two Years' Experience," J. Biomed. Mater. Res ., 5:373 (1971).
2.
Boretos, J.W."Tissue Pathology and Physical Stability of a Polyether Elastomer on Three-Year Implantation;'J. Biomed. Mater. Res., 6:473 (1972).
3.
Lelah, M.D. and S.L. Cooper.Polyurethanes in Medicine. Boca Raton, FL: CRC Press, Inc. (1986).
4.
Coleman, D.L. , D. Lim, T. Kessler and J.D. Andrade."Calcification of Non-textured Implantable Blood Pumps;'Trans. Am. Soc. Artif. Intern. Organs,27:97 ( 1981).
5.
Glasmacher, B., H. Reul, G. Rau, C. Erckes and J. Weitland."In vitro Investigation of the Calcification Behavior of Polyurethane Biomaterials," in Polyurethanes in Biomedical Engineering II, Progress in Biomedical Engineering, 3. H. Planck, I. Syre, M. Dauner and G. Egbers, eds. Amsterdam: Elsevier, p. 151 (1987).
6.
Stokes, K. and B. Chem. "Environmental Stress Cracking in Implantable Polyurethanes," in Polyurethanes in Biomedical Engineering, Progress in Biomedical Engineering, 1. H. Planck, G. Egbers and I. Syre, eds. Amsterdam:Elsevier, p. 243 (1984).
7.
Stokes, K., A. Coury and P. Urbanski. "Autooxidative Degradation of Implantable Polyether Polyurethane Devices," J. of Biomatls. Applications, 1: 471 (1987).
8.
Levy, R.J., F.J. Schoen, F.S. Sherman, J. Nichols, M.A. Hawley and S.A. Lund. "Calcification of Subcutaneously Implanted Type I Collagen Sponges,"American J. of Pathology, 122:71 (1986).
9.
Harasaki, H.J. , J. McMahon, T. Richardo, J. Goldcamp, R. Kiraly and Y. Nóse."Calcification in Cardiovascular Implants: Degraded All Related Phenomena;'Trans. Am. Soc. Artif. Intern. Organs, 31:489 (1985).
10.
Harasaki, H., Y. Nose, J. McMahon, R. Kiraly, W. Smith, A. Moritz, S. Murabayashi and T. Richards.Program and Abstracts, Devices and Technology Branch Contractors Meeting, Division of Heart and Vascular Disease, National Heart, Lung, and Blood Institute, p. 114 (December, 1986).
11.
Thoma, R.J., T.Q. Hung, E. Nyilas, A.D. Haubold and R.E. Phillips. "Metal Ion Complexation of Poly(ether) Urethanes," in-Advances in Biomedical Polymers. C. G. Gebelein, ed. Plenum Publishing Corporation, p. 131 (1987).
12.
Phillips, R.E. and R.J. Thoma. "Metal Ion Complexation of Polyurethanes: A Proposed Mechanism for Calcification," in Polyurethanes in Biomedical Engineering II, Progress in Biomedical Engineering, 3. H. Planck, I. Syre, M. Dauner and G. Egbers, eds. Amsterdam:Elsevier, p. 91 (1987).
13.
Thoma, R.J. "Poly(ether) Urethane Reactivity with Metal Ion in Calcification and Environmental Stress Cracking," J. of Biomaterials Applications, 1:449 (1987).
14.
Hamon, R.F. , A.S. Khan and A. Chow. "The Cation Chelation Mechanism of Metal Ion Sorption by Polyurethanes," Talanta, 29:313 (1982).
15.
Stokes, K. B., A.W. Frazer and E.A. Carter. "The Biostability of Various Polyether Polyurethanes Under Stress," presented at the SPE ANTEC Meeting, New Orleans, LA (May, 1984).
16.
The Stimarec Bulletin, 1 (July 31, 1982).
17.
Ibid, 1 (October 31, 1983).
18.
Phillips, R. , M. Frey and R. Martin. "Long Term Performance of Palyurethane Pacing Leads: Mechanism of Design Related Failures," PACE , 9:1166 (1986).
19.
Parins, D.H., K.M. Black, K.D. McCoy and N.J. Horvath.In vivo Degradation of a Polyurethane: Further Evidence . St. Paul, MN:Cardiac Pacemakers, Inc. (1981).
20.
Phillips, R., J. Sluetz and D. Cogan. "Segmented Polyether Polyurethanes for Pacing Leads: Evidence for Biostability," Proceedings of the International Symposium on Pacemaker Leads, Leuven, Belgium, p. 79 (1984).
21.
Ratner, B.D., R.W. Paynter and H.R. Thomas. "Polyurethanes Surfaces-an XPS Study," presented at the 9th Annual Meeting of the Society for Biomaterials, April 27-May 1, 1983, Birmingham, AL.
22.
Sung, P. and A.C. Fraker. "Corrosion and Degradation of Polyurethane/ MP35N Pacing Lead," Transactions of the 13th Annual Meeting of the Society for Biomaterials, X:13 (June, 1987).
23.
Thoma, R.J. and R.E. Phillips. "Note: Studies of Poly(ether) Urethane Pacemaker Lead Insulation Oxidation," J. of Biomed. Mater. Res., 21:525 (1987).
24.
Christenson, C.P., M.A. Harthcock, M.D. Meadows, H.L. Spell, W.L. Howard, M.W. Creswick, R.E. Guerra and R.B. Turner. "Model MDI/ Butanediol Polyurethanes: Molecular Structure, Morphology, Physical and Mechanical Properties," J. of Poly. Sci.: Part B: Polymer Physics, 24: 1401 (1986).
25.
Private communication with R. J. Thoma, Carbomedics, Inc., Austin, Texas.
