In vitro andin vivo degradation of bioabsorbable PLLA spinal fusion cages

✍ Scribed by van Dijk, M. ;Tunc, D. C. ;Smit, T. H. ;Higham, P. ;Burger, E. H. ;Wuisman, P. I. J. M.

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 597 KB
• Volume: 63
• Category: Article
• ISSN: 0021-9304
• DOI: 10.1002/jbm.10466

✦ Synopsis

Abstract

The in vitro and in vivo degradation of poly‐L‐lactic acid cages used as an adjunct to spinal arthrodesis was investigated. In the in vitro experiments cages were subjected to aging up to 73 weeks in phosphate‐buffered solution (pH 7.4) at 37 °C. Inherent viscosity, crystallinity, and mechanical strength were determined at different time points. In the in vivo study, the poly‐L‐lactic acid cages were packed with bone graft and implanted in the L3‐L4 spinal motion segment of 18 Dutch milk goats. At 12, 26, and 52 weeks, the motion segments were isolated and poly‐L‐lactic acid samples retrieved. On evaluation, the in vivo implanted cages showed an advanced decline in inherent viscosity compared to the cages subjected to in vitro degradation experiments. At 6 months of implantation, the geometrical shape and original height of 10 mm was maintained during 6 months of follow up. This finding fits well with the observation that mechanical strength was maintained for a period of 6 months in vitro. At 12 months, the poly‐L‐lactic acid cage had been disintegrated into multiple fragments with signs of absorption. Despite the high–load‐bearing conditions, the poly‐L‐lactic acid cage allowed interbody fusion to occur without collapse of the cage. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 752–759, 2002