Late tissue reactions and degradation of biodegradable polylactide implants. An experimental study in rats
Laat optredende weefselreacties en degradatie van afbreekbare polylactide implantaten. Een experimenteel onderzoek in de rat
26 May 2012, PDF |
38 pages |
de Jong WH, van Rozendaal AWM, Bergsma JE, Joziasse CAP, Teppema JS, Rozema FR, Dorpema JW, Bos RRM, van Asten JAAM
RIVM Report 605148006
Biodegradable poly(L-lactide) (PLLA) plates and screws are currently being used as an alternative for metal plates and screws for the fixation of bone fractures. However, in patients treated with as-polymerized poly(L-lactide) (PLLA), a swelling at the site of implantation was observed after three and more years following the implantation. In this study a comparison was made between the histopathological reaction to non-degraded and predegraded as-polymerized PLLA, and as a control, polyethylene (PE) disks implanted subcutaneously in rats. In addition, another recently developed poly(96%L,4%D-lactide) (PLA96) was tested that possesses lower crystallinity that probably results in a faster and more complete degradation. The histological reaction to the predegraded implants was qualitatively similar to the reaction to the non-degraded implants, however, quantitatively an increase was noted. The local swelling observed in vivo with the predegraded PLLA and PLA96 showed histologically similar characteristics as material explanted from patients. The results of this study indicate that in vitro predegradation followed by in vivo implantation might be used as a model to predict late complications of biodegradable implants. At the moment biodegradable materials are not included in the ISO/CEN 10993-6 guidelines: Biological evaluation of medical devices. Part 6 Tests for local effects after implantation. The described model, in vitro predegradation followed by in vivo implantation, might be suited as an implantation assay for biodegradable materials.