Patent ID: 8425568

Claim:
A method for treating a deformity of a spine, the spine comprising a plurality of vertebrae each having a first lateral portion, a central spinous process portion, and a second lateral portion on a side of the central spinous process portion opposite to the first lateral portion, the method comprising: attaching a first anchor to the first lateral portion of a first vertebra of the spine; attaching a second anchor to the first lateral portion of a second vertebra of the spine; attaching a third anchor to the second lateral portion of the first vertebra; attaching a fourth anchor to the second lateral portion of the second vertebra; pre-stressing a first dual spring member between the first anchor and the second anchor and attaching the first dual spring member to the first anchor and the second anchor so as to apply a first force between the first lateral portion of the first vertebra and the first lateral portion of the second vertebra, wherein the first dual spring member comprises a first outer coil spring and a first inner coil spring inside the first outer coil spring, wherein the first outer coil spring has a first working length, wherein the first working length is a length through which the first outer coil spring extends through turns along a free portion of the first outer coil spring over which the first outer coil spring is free to bend or compress, wherein the first inner coil spring has a second working length, wherein the second working length is a length through which the first inner coil spring extends through turns along a free portion of the first inner coil spring over which the first inner coil spring is free to bend or compress, and wherein the first working length is substantially equal to the second working length; pre-stressing a second dual spring member between the third anchor and the fourth anchor and attaching the second dual spring member to the third anchor and the fourth anchor so as to apply a second force between the second lateral portion of the first vertebra and the second lateral portion of the second vertebra, wherein the second dual spring member comprises a second outer coil spring and a second inner coil spring inside the second outer coil spring, wherein the second outer coil spring has a third working length, wherein the third working length is a length through which the second outer coil spring extends through turns along a free portion of the second outer coil spring over which the second outer coil spring is free to bend or compress, wherein the second inner coil spring has a fourth working length, wherein the fourth working length is a length through which the second inner coil spring extends through turns along a free portion of the second inner coil spring over which the second inner coil spring is free to bend or compress, and wherein the third working length is substantially equal to the fourth working length; and treating the deformity by application of the first force and the second force.