Photocrosslinked poly(anhydrides) for spinal fusion: characterization and controlled release studies.

Abstract

Spinal instability resulting from trauma or disease can be treated by spinal fusion, a surgical procedure that eliminates or minimizes motion at a site of degeneration in the spinal column. Autologous bone harvested from the iliac crest remains the gold standard material for use in these procedures. There are drawbacks to iliac crest harvest, however, such as limited bone availability and post-operative morbidity due to long-term discomfort at the donor site. These limitations form the basis and serve as the motivating elements in the development of synthetic alternatives. An ideal polymeric biomaterial for spinal fusion should fulfill the following criteria: capability of in situ formation, conformability to the implantation site, provision of mechanical stability, controllable degradation, osteogenicity, and biocompatibility. The objectives of this dissertation were therefore the: (1) development of a material that meets these criteria for use in spinal fusion, (2) adaptation of the material to provide sustained release of proteins, and (3) modulation of the material to provide variable release of multiple proteins. In fulfilling these objectives, we have developed and optimized a novel polymeric system for use in the spine with the additional capability of long-term sustained release of biologically active macromolecules. Our results suggest that this system may be useful as an injectable delivery system for spinal fusion applications that provides both mechanical stabilization and delivery of growth factors to stimulate new bone growth.