Apparatus and system for fusing bone joints

Claim 1

A method for stabilizing a human or animal joint, such as a spinal joint between adjacent vertebrae, formed by opposed bony surfaces covered and separated by intervening cartilage and surrounded by ligaments which resist expansion of the joint, and promoting bone growth across the stabilized joint, the method comprising the following steps: surgically accessing the joint; selecting a suitably sized fusion implant for placement between the opposed bony surfaces of the joint, the fusion implant including: (a) a coil formed as a length of wire that is spirally wound in repetitive turns centered about a common reference axis, the wire being constructed of elastic material capable of restoring the turns of the coil to radially expanded states after the coil has been twisted about the reference axis to a torqued state where the turns of the coil have reduced diameters; (b) the coil encircling an axial implant cavity adapted to receive material promoting bone ingrowth through the implant; (c) the wire including first and second terminal sections at opposite ends of the coil adapted to facilitate gripping of the wire and relative twisting of the ends of the coil about the reference axis; (d) the coil having sufficient compressive strength and elasticity to maintain separation between bony surfaces of a prepared joint when implanted and permitted to assume a conforming expanded state; (e) the implanted coil being adapted to have no interconnections attached to its turns that would interfere with projection of prepared bone surfaces radially inward into its axial implant cavity; gripping the first and second terminal sections; twisting the coil in the direction in which the wire is wound about the reference axis to a reduced diameter torqued state in which the outer diameter of the coil is less than its outer diameter while in its relaxed state; introducing the twisted coil between the opposed bony surfaces of the joint; and releasing one or both terminal sections of the coil to allow the coil to assume an expanded state, whereby the outer diameter of the coil is radially enlarged relative to its torqued state and the joint is immediately stabilized by spreading the bony surfaces apart in opposition to the resistance to expansion of the joint provided by the surrounding ligaments.

Claim 2

A method for stabilizing a human or animal joint, such as a spinal joint between adjacent vertebrae, formed by opposed bony surfaces covered and separated by intervening cartilage and surrounded by ligaments which resist expansion of the joint, and promoting bone growth across the stabilized joint, the method comprising the following steps: surgically accessing the joint; selecting a suitably sized fusion implant for placement between the opposed bony surfaces of the joint, the fusion implant including: (a) a coil formed as a length of wire that is spirally wound in repetitive turns centered about a common reference axis, the wire being constructed of elastic material capable of restoring the turns of the coil to radially expanded states after the coil has been twisted about the reference axis to a torqued state where the turns of the coil have reduced diameters; (b) the coil encircling an axial implant cavity adapted to receive material promoting bone ingrowth through the implant; (c) the wire including first and second terminal sections at opposite ends of the coil adapted to facilitate gripping of the wire and relative twisting of the ends of the coil about the reference axis; (d) the coil having sufficient compressive strength and elasticity to maintain separation between bony surfaces of a prepared joint when implanted and permitted to assume a conforming expanded state; (e) the implanted coil being adapted to have no interconnections attached to its turns that would interfere with projection of prepared bone surfaces radially inward into its axial implant cavity; gripping the first and second terminal sections; twisting the coil in the direction in which the wire is wound about the reference axis to a reduced diameter torqued state in which the outer diameter of the coil is less than its outer diameter while in its relaxed state; introducing the twisted coil between the opposed bony surfaces of the joint; and releasing one or both terminal sections of the coil to allow the coil to assume an expanded state, whereby the outer diameter of the coil is radially enlarged relative to its torqued state and the joint is immediately stabilized by spreading the bony surfaces apart in opposition to the resistance to expansion of the joint provided by the surrounding ligaments.