Patent ID: 7850730

Claim:
A method for implanting a hydrogel prosthesis within an intervertebral disc, the method comprising the steps of: a) advancing a first guidewire through tissue surrounding an intervertebral disk until an end portion of said first guidewire contacts an outer wall of an annulus fibrosus of said intervertebral disc; b) advancing over said first guidewire a prosthesis insertion cannula, said prosthesis insertion cannula having a distal end adapted to be inserted through said annulus fibrosus of said intervertebral disc, a proximal end, and a delivery lumen extending between said proximal end and said distal end, said delivery lumen sized to slide over said first guidewire, said prosthesis insertion cannula being advanced until said distal end thereof contacts said outer wall of said annulus fibrosus; c) removing said first guidewire from said delivery lumen; d) advancing through said delivery lumen a second guidewire sized to be passed through said delivery lumen of said prosthesis insertion cannula and having a distal end adapted to pierce the annulus fibrosus of the intervertebral disc, until said distal end of the second guidewire has pierced said annulus fibrosus and extends into a nucleus pulposus region of said intervertebral disc; e) advancing said prosthesis insertion cannula over said second guidewire until said distal end of said prosthesis insertion cannula extends into said nucleus pulpous region of said intervertebral disc; f) removing said second guidewire from said delivery lumen, thereby leaving an open channel into said nucleus pulposus region of said intervertebral disc; g) optionally, removing nucleus pulposus tissue from said nucleus pulposus through said open channel; h) determining a volume within said intervertebral disc to be filled by said hydrogel prosthesis by inserting an inflatable highly compliant balloon through said delivery lumen of said prosthesis insertion cannula, inflating said balloon with a fluid such that the highly compliant balloon reaches a fully distended state when inflated with about 3 psi, the balloon being inflated to a pressure between 20 psi to 40 psi at which the intervertebral disc is adequately pressurized to restore the natural mechanical properties of the intervertebral disc and measuring the volume of said fluid required to inflate said balloon to said pressure of between 20 psi to 40 psi; i) coupling to said proximal end of said prosthesis delivery cannula a distal end of a storage tube, said storage tube containing a predetermined amount of the hydrogel prosthesis, said predetermined amount of hydrogel prosthesis substantially corresponding to said measured volume of said fluid; j) coupling a proximal end of said storage tube to a source of fluid pressure; k) applying said fluid pressure to said proximal end of said storage tube to force said hydrogel prosthesis through said delivery lumen of said prosthesis delivery cannula and into said nucleus pulposus region; l) removing said prosthesis delivery cannula from said intervertebral disc.