Spinal fusion methods and devices

• US 8,617,252 B2
• Filed: 08/07/2009
• Issued: 12/31/2013
• Est. Priority Date: 10/24/2000
• Status: Expired due to Term

• Current Assignee: Warsaw Orthopedic Incorporated (Medtronic Plc)
• Original Assignee: Warsaw Orthopedic Incorporated (Medtronic Plc)
• Inventors: McKay, William F.
• Primary Examiner(s): Willse, David H
• Assistant Examiner(s): BLANCO, JAVIER G
• Application Number:
  US12/537,701
• Publication Number:
  US 20090298777A1
• Time in Patent Office: 1,607 Days
• Field of Search: None
• US Class Current: 623/23.61
• CPC Class Codes: A61B 17/58 for osteosynthesis, e.g. bone plates, screws , setting implements or the like A61B17/14, A61B17/16 take precedence
• CPC Class Codes: A61B 2017/564 Methods for bone or joint treatment
• CPC Class Codes: A61F 2/442 Intervertebral or spinal discs, e.g. resilient non-disc-shaped intervertebral inflatable pockets A61F2/441; non-disc-shaped intervertebral fusion implants A61F2/4455
• CPC Class Codes: A61F 2/4455 for the fusion of spinal bodies, e.g. intervertebral fusion of adjacent spinal bodies, e.g. fusion cages intervertebral discs A61F2/442
• CPC Class Codes: A61F 2002/2817 Bone stimulation by chemical reactions or by osteogenic or biological products for enhancing ossification, e.g. by bone morphogenetic or morphogenic proteins [BMP] or by transforming growth factors [TGF]
• CPC Class Codes: A61F 2002/30062 (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• CPC Class Codes: A61F 2002/30092 using shape memory or superelastic materials, e.g. nitinol
• CPC Class Codes: A61F 2002/4635 using minimally invasive surgery
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61F 2210/0014 using shape memory or superelastic materials, e.g. nitinol
• CPC Class Codes: A61F 2310/00293 containing a phosphorus-containing compound, e.g. apatite
• CPC Class Codes: A61F 2310/00353 Bone cement, e.g. polymethylmethacrylate or PMMA
• CPC Class Codes: A61F 2310/00365 Proteins; Polypeptides; Degradation products thereof
• CPC Class Codes: A61L 2430/38 for reconstruction of the spine, vertebrae or intervertebral discs
• CPC Class Codes: A61P 19/08 for bone diseases, e.g. rachitism, Paget's disease

Abstract

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 intervertebral 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 morphogenetic 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.

Claims

1. An intervertebral fusion device comprising an osteoinductive composition for treating bone defects, the osteoinductive composition present in an amount effective to induce bone growth to form a bone mass in a location for fusing adjacent vertebrae, said composition comprising:

a biodegradable collagen carrier comprising a polymer matrix and pores forming a sponge matrix,

bone morphogenetic protein 2 (BMP-2) entrained within the carrier, and

LIM mineralization protein-1 (LMP-1) entrained within the carrier;

wherein the bone morphogenetic protein 2 is present in an amount of 0.5 mg/ml to 4 mg/ml of the biodegradable collagen carrier,

wherein the carrier further comprises calcium phosphate and has a calcium to phosphate (Ca/P) ratio of about 0.4 to about 0.6, and the carrier has a porosity of greater than 40%,

wherein the osteoinductive composition is sufficient to deliver 2 mg of bone morphogenetic protein 2 to 40 mg of bone morphogenetic protein 2, and

wherein the carrier is configured to be substantially impermeable to efflux of the entrained osteoinductive composition in vivo sufficiently that the formed bone mass is confined to the volume of the carrier when implanted, and wherein the carrier gradually exposes the entrained osteoinductive composition at said location as it degrades.

2. An intervertebral fusion device of claim 1, wherein said calcium phosphate comprises tricalcium phosphate.

3. An intervertebral fusion device of claim 2, wherein said composition further comprises hydroxyapatite.

4. An intervertebral fusion device of claim 1, wherein said bone morphogenetic protein 2 is a recombinant human bone morphogenetic protein.

5. An intervertebral fusion device of claim 1, wherein said composition further comprises transforming growth factors, insulin-like growth factors, epidermal growth factors, platelet-derived growth factors and fibroblast growth factors.

6. An intervertebral fusion device of claim 1, wherein less than about 50% by weight of the osteoinductive composition is released from the carrier after about 2, 4, 7, 10 or about 14 days post implantation.