Trauma, oncologic surgery, and congenital disorders often leave patients with large bony defects that require reconstruction. Autografts and allografts are used in current bone graft procedures to repair defects. However, each has clinical drawbacks. The proposed bioresorbable bone graft substitute is made from the unsaturated polyester, poly(propylene glycol-co-fumaric acid), which can be cross-linked in the presence of soluble and insoluble calcium filler salts and grouted directly into a bony void. This graft substitute provides an osteoconductive pathway for bone ingrowth. In Phase I the technical objective was to demonstrate the feasibility of a degradable grout to encourage bony ingrowth and void filling by the use of soluble fillers. Following this demonstration of a relationship between salt-promoted porosity of the bone graft substitute and cell ingrowth in Phase I, the investigators now propose in Phase II the in vivo evaluation of grouts which encourage optimal ingrowth of bone cells and organized deposition of new bone. It is projected that the work will result in a grout formulation using a mixture of calcium salts that will leach from the graft substitute at a rate supportive of the overall structural integrity of the repairing site, while optimum rates of bone ingrowth and polymer degradation are maintained.
There are over 450,000 bone graft procedures annually in the U.S. (2.2 million worldwide) with a market potential of $400 to $600 million. The approved synthetic grafts are considered to be inferior to the use of autograft or allograft materials. Bioresorbable bone void fillers could provide a viable alternative to autografts and allografts used in current bone graft procedures to repair defects caused by surgery, tumors, trauma, implant revisions and infecctions and also for joint fusion.
| Hile, David D; Kandziora, Frank; Lewandrowski, Kai-Uwe et al. (2006) A poly(propylene glycol-co-fumaric acid) based bone graft extender for lumbar spinal fusion: in vivo assessment in a rabbit model. Eur Spine J 15:936-43 |
