Method and apparatus for closing fissures in the annulus fibrosus
A filament laterally spans a tear, fissure or other defect in an annulus. One portion of the filament is anchored to the annulus by passing at least one first anchor through the annulus and into the nucleus on one side of the fissure, and with a second portion of the filament being anchored to the annulus by passing at least one second anchor through the annulus and into the nucleus on a second side of the fissure, with the at least one first and second anchors being drawn back through the nucleus and against the inner surface of the posterior annulus by the application of a significant (e.g., about 15N to 25N) axial tension applied perpendicular to the posterior wall of the annulus, and with the fissure being drawn closed by the subsequent application of a significant axial tension applied perpendicular to the posterior wall of the annulus.
1. A method of closing a fissure or other defect in an annulus fibrosus (AF) having an outer surface and an inner surface, the method comprising the steps of:
providing a flexible longitudinal fixation component terminating in a distal end coupled to a first anchor component, and a proximal second anchor component slidingly coupled along the flexible longitudinal fixation component, wherein at least one of the first anchor component and the second anchor component comprise a hole for receiving the flexible longitudinal fixation component and a projection for (i) permitting the flexible longitudinal fixation component to slide through the hole in a first direction, and (ii) preventing the flexible longitudinal fixation component from sliding through the hole in a second direction;
inserting the first anchor component through a first insertion point in the AF from the inside out on one side of the defect in the AF such that the first anchor component passes the inner surface of the AF and a first exposed portion of the flexible longitudinal fixation component extends outwardly from the first insertion point;
applying tension to the first exposed portion of the flexible longitudinal fixation component such that the first anchor component becomes firmly seated against the inner surface of the AF;
inserting the second anchor component through a second insertion point in the AF from the inside out on the other side of the defect in the AF such that the first exposed portion crosses over the defect and into the second insertion point, and a second exposed portion of the flexible longitudinal fixation component extends outwardly from the second insertion point; and
applying tension to the second exposed portion such that the flexible longitudinal fixation component slides through the second anchor component, applying tension to the first exposed portion, thereby closing the defect in the AF and causing the second anchor to become firmly seated against the inner surface of the AF.
2. The method of claim 1 , wherein the tension applied to the first exposed portion is in the range of about 15 N to 25 N.
3. The method of claim 1 , wherein the tension applied to the second exposed portion is in the range of about 15 N to 25 N.
4. The method of claim 1 , wherein the flexible longitudinal fixation component is a surgical suture.
5. The method of claim 1 , wherein the projection prevents further sliding of the flexible longitudinal fixation component following the step of applying tension to the second exposed portion.
6. The method of claim 1 , wherein the process is repeated with one or more additional anchors slidingly coupled at different points along the flexible longitudinal fixation component such that two or more exposed portions cross of the defect when the process is completed.
7. The method of claim 1 , wherein the one or both of the anchor components are elongated such that they penetrate the AF axially and turn once past the inner surface of the AF to better prevent pull-out.
8. The method of claim 1 , wherein the one or both of the anchor components are inserted with a pointed, cannulated insertion instrument that penetrates the AF and deploys each anchor component with a stylus or push rod.
9. The method of claim 1 , including the step of anchoring the flexible longitudinal fixation component to one of an upper and lower vertebral body.
10. The method of claim 1 , including the step of trimming the second exposed portion of the flexible longitudinal fixation component.
11. The method of claim 1 wherein the hole is substantially perpendicular to the longitudinal axis of the anchor component.
12. The method of claim 1 wherein the anchor component comprises two holes, and further wherein the two holes are substantially perpendicular to the longitudinal axis of the anchor component.