SPINAL FUSION METHODS AND DEVICES
Methods, devices and compositions for fusing adjacent vertebrae, and otherwise localizing bone growth, are provided. In one form of the invention, a method for fusing adjacent vertebrae includes preparing a disc space for receipt of an intervertebral disc implant in an interwertebral disc space between adjacent vertebrae, inserting the implant into the intervertebral disc space and providing an osteoinductive composition that includes an osteoinductive factor in a pharmaceutically acceptable carrier. The carrier is advantageously substantially impermeable to efflux of the osteoinductive factor and is released as the carrier is resorbed or biodegraded. Preferred carriers include a hardened, resorbable carrier, such as a calcium phosphate cement that retains at least about 50% of the osteoinductive factors greater than about 2 days. Preferred osteoinductive factors are growth factors and include bone morphogenctic proteins and LIM mineralization proteins. In alternative forms of the invention, the method may be performed without utilization of a load-bearing spinal implant by disposing the osteoinductive composition in the disc space. The method is advantageously performed on lumbar vertebrae by a posterior approach. Intervertebral fusion devices and methods for their preparation are also provided.
1 - 10 . (canceled)
11 . An osteoinductive composition for generating a bone mass in a patient, the osteoinductive composition comprising bone morphogenetic protein 2 within a biodegradable carrier comprising calcium phosphate the biodegradable carrier being substantially impermeable to efflux of said bone morphogenetic protein 2 so that the formed bone mass is confined to a volume of the carrier, wherein the bone morphogenetic protein 2 is present in an amount of 0.5 mg/ml to 4 mg/ml of the calcium phosphate and the bone morphogenetic protein 2 is released from the biodegradable carrier as the biodegradable carrier degrades.
12 . An osteoinductive composition of claim 11 , wherein said composition further comprises collagen.
13 . An osteoinductive composition of claim 11 , wherein said calcium phosphate comprises tricalcium phosphate.
14 . An osteoinductive composition of claim 13 , wherein said composition further comprises hydroxyapatite.
15 . An osteoinductive composition of claim 11 , wherein said bone morphogenetic protein 2 is recombinant human bone morphogenetic protein 2.
16 . An osteoinductive composition claim 11 , wherein said biodegradable carrier has a closed pore structure.
17 . An osteoinductive composition claim 11 , wherein said calcium phosphate is a cement and comprises tricalcium phosphate or hydroxyapatite or combinations thereof.
18 . An osteoinductive composition of claim 11 , wherein said osteoinductive composition further comprises an osteoinductive factor selected from the group consisting of LIM mineralization protein, transforming growth factors, insulin-like growth factors, epidermal growth factors, platelet-derived growth factors and fibroblast growth factors.
19 - 20 . (canceled)
21 . An osteoinductive composition of claim 11 , wherein said composition is inserted into a disc space.
22 . An osteoinductive composition of claim 11 , wherein said composition has a chamber for receipt of said bone morphogenetic protein 2.
23 . (canceled)
24 . An osteoinductive composition of claim 11 , wherein less than about 50% by weight of the bone morphogenetic protein 2 is released from the carrier after about 2 days post implantation.
25 . An osteoinductive composition of claim 11 , wherein less than about 50% by weight of the bone morphogenetic protein 2 is released from the carrier after about 7 days post implantation.
26 - 37 . (canceled)