Percutaneous prosthetic spinal disc nucleus and method of manufacture

Claim 1

A prosthetic spinal disc nucleus for implantation into a nucleus cavity of a spinal disc, the nucleus cavity defined by an opposing pair of vertebral bodies, forming opposing end plates, and an anulus, the prosthetic spinal disc nucleus comprising: a substantially inelastic constraining jacket having a generally fixed maximum volume determined by a generally fixed circumference and length, the maximum volume being less than a volume of the nucleus cavity, wherein the constraining jacket defines a height corresponding to a plane substantially perpendicular to the opposing end plates, and further wherein, upon implantation, the constraining jacket is configured such that the opposing end plates force the constraining jacket to an initial implant volume in which the constraining jacket is oval in cross-section; and an amorphous polymer core inserted into the constraining jacket, the polymer core configured to be flowable in at least a first state such that upon insertion, the amorphous polymer core fills the initial implant volume of the constraining jacket and creates an internal pressure within the constraining jacket, the constraining jacket being configured to transition from the initial implant volume toward the maximum volume, increasing substantially in height in response to the internal pressure.

Claim 18

A method of manufacturing a prosthetic spinal disc nucleus implanted into a nucleus cavity of a spinal disc, the method comprising: providing a substantially inelastic constraining jacket having a generally fixed maximum volume determined by a generally fixed circumference and length, the maximum volume being less than a volume of the nucleus cavity, and wherein the constraining jacket defines a height corresponding to a transverse plane of the nucleus cavity, and further wherein the constraining jacket is configured such that upon implantation, the constraining jacket is forceable to an initial implant volume in which the constraining jacket is oval in cross-section; providing an amorphous polymer core that is flowable in at least a first state; inserting the amorphous polymer core in the first state into the constraining jacket such that the amorphous polymer core fills the initial implant volume of the constraining jacket; and generating an internal pressure within the constraining jacket, wherein the constraining jacket transitions from the initial implant volume toward the maximum volume, increasing substantially in height in response to the internal pressure.

Claim 19

A method of manufacturing a prosthetic spinal disc nucleus implanted into a nucleus cavity of a spinal disc, the method comprising: providing a substantially inelastic constraining jacket having a generally fixed maximum volume determined by a generally fixed circumference and length, the maximum volume being less than a volume of the nucleus cavity, and wherein the constraining jacket defines a height corresponding to a transverse plane of the nucleus cavity, and further wherein the constraining jacket is configured such that upon implantation, the constraining jacket is forceable to an initial implant volume in which the constraining jacket is oval in cross-section; providing an amorphous polymer core that is flowable in at least a first state; inserting the amorphous polymer core in the first state into the constraining jacket such that the amorphous polymer core fills the initial implant volume of the constraining jacket; and generating an internal pressure within the constraining jacket, wherein the constraining jacket transitions from the initial implant volume toward the maximum volume, increasing substantially in height in response to the internal pressure.