Injection Molding of Vertebral Fixed Cage Implant

  • Yoo, Kyun Min (School of Materials Science and Engineering, Seoul national University) ;
  • Lee, Seok Won (School of Materials Science and Engineering, Seoul national University) ;
  • Youn, Jae Ryoun (School of Materials Science and Engineering, Seoul national University) ;
  • Yoon, Do Heum (Department of Neurosurgery, College of Medicine, Yonsei University) ;
  • Cho, Yon Eun (Department of Neurosurgery, College of Medicine, Yonsei University) ;
  • Yu, Jae-Pil (Kyungwon Medical Company) ;
  • Park, Hyung Sang (Kyungwon Medical Company)
  • Published : 2003.06.01

Abstract

A vertebral cage is a hollow medical device which is used in spine forgery. By implanting the cage into the spine column, it is possible to restore disc and relieve pressure on the nerve roots. Most cages have been made of titanium alloys but they detract the biocompatibility. Currently PEEK (polyether ether ketone) if applied to various implants because it has good properties like heat resistance, chemical resistance, strength, and especially biocompatibility. A new shape of vertebral cage is designed and injection molding of PEEK is considered for production. Before injection molding of the cage, it is needed to evaluate process conditions and properties of the final product. Variables affecting the shrinkage of the cage are considered, e.g., injection time, packing pressure, mold temperature, and melt temperature. By using the numerical simula-tion program, MOLDFLOW, several cases are studied. Data files obtained by MOLDFLOW analysis are used for stress anal-ysis with ABAQUS, and shrinkage and residual stress fields are predicted. With these results, optimum process conditions are determined.

Keywords

References

  1. C. D. Ray, Neurosurgery Quarterly, 7, 125 (1997)
  2. J. W. Brantigan and K. Warden, Spine, 18, 1213 (1993) https://doi.org/10.1097/00007632-199307000-00015
  3. S. Middleman, 'Fundamentals of Polymer Processing', McGraw-Hill, New York, 1977
  4. J. M. Mckelvey, 'Polymer Processing', John Wiley and Sons, New York, 1962
  5. Z. Tadmor and C. G. Gogos, 'Principles of Polymer Processing', John Wiley and Sons, New York, 1980
  6. H. H. Chiang, C. A. Hieber, and K. K. Wang, Polym. Eng. Sci., 31, 116 (1991) https://doi.org/10.1002/pen.760310210
  7. H. H. Chiang, C. A. Hieber, and K. K. Wang, Polym. Eng. Sci., 31, 125 (1991) https://doi.org/10.1002/pen.760310211
  8. J. Ko and J. R. Youn, Polym. Compos., 16, 114 (1995) https://doi.org/10.1002/pc.750160203
  9. V. Leo and C. Cuvellifz, Polym. Eng. sci., 36, 1961 (1996) https://doi.org/10.1002/pen.10592
  10. M. Akay and S. Ozden, Polym. Eng. Sci., 36, 1839 (1996) https://doi.org/10.1002/pen.10579
  11. K. Shlesh-Nezhad and E. Siores, J. Mater. Process. Tech., 63, 458 (1997) https://doi.org/10.1016/S0924-0136(96)02664-7
  12. S. C. Lee, D. Y. Yang, J. Ko, and J. R. Youn, J. Mater. Process. Tech., 70, 83 (1997) https://doi.org/10.1016/S0924-0136(97)00041-1
  13. V. W. S. Yung and K. H. Lau, J. Mater. Process. Tech., 63, 481 (1997) https://doi.org/10.1016/S0924-0136(96)02669-6
  14. S. C. Lee and J. R. Youn, J. Reinf Plast. Comp., 18, 186 (1999) https://doi.org/10.1177/073168449901800205
  15. J. H. Jung, S. W. Lee, and J. R. Youn, Macromol. Symp., 148, 263 (1999) https://doi.org/10.1002/masy.19991480120
  16. S. W. Lee and J. R. Youn, Macromol. Symp., 148, 211 (1999) https://doi.org/10.1002/masy.19991480117
  17. D. Choi and Y. lm, Compos. Struct., 47, 655 (1999) https://doi.org/10.1016/S0263-8223(00)00045-3
  18. D. H. Chung and T. H. Kwon, Korea-Australia Rheology J., 12, 125 (2000)
  19. S. W. Lee, J. R. Youn, and J. C Hyun, Mater. Res. lnnov., 6, 189 (2002) https://doi.org/10.1007/s10019-002-0189-z
  20. K. S. Lee, S. W. Lee, K. Chung, T. J. Kang, and J. R. Youn, J. Appl. Polym. sci., 88, 500 (2003) https://doi.org/10.1002/app.11757
  21. K. M. B. Jansen and G. Titornanlio, Polym. Eng. sci., 38, 254 (1998) https://doi.org/10.1002/pen.10186
  22. W. F. Zoetelief and J. Ingenhousz, Polym. Eng. Sci., 36, 1886 (1996) https://doi.org/10.1002/pen.10585
  23. Y. I. Kwon, T. J. Kang, K. Chung, and J. R. Youn, Fiber. Polym., 2, 203 (2001) https://doi.org/10.1007/BF02875346
  24. S. K. Kim. S. W. Lee. and J. R. Youn. Korea-Australia Rheology J., 14, 107 (2002)
  25. K. K. Kabenami and H. Wang, Polym. Eng. Sci., 38, 21 (1998) https://doi.org/10.1002/pen.10162
  26. L. E. Malvern, 'Introduction to the Mechanics of a Continuous Medium", Prentice-Hall, Englewood Cliff, 1969