Abstract: Cutter assemblies for use with cutter blades made of shape memory materials. The cutter blades may be deployed in the interior of an intervertebral disc space and rotated relative to a central axis of the cutter assembly to cut the material present for removal from the intervertebral disc space. Cutter blades with different attributes (such as throw length, cutter blade angle, type and location of blade edges) are adapted to achieve different objectives within the intervertebral disc space. Some cutter blades are adapted to promote bleeding of cartilage and vertebral body endplates and some cutter blades are adopted to avoid causing such bleeding. Closed loop cutter blades are described which have certain desirable attributes including the ability to remove the entire cutter blade from the intervertebral disc space after a break in the blade. Serration patterns are disclosed including a serration pattern that makes use of trapezoidal serrations.

Abstract: An exchange system is disclosed, for providing a protected path to a subcutaneous procedure site. An exchange cannula is provided with a central lumen, and a drill wire lumen that serves as a portal for a drill wire for coupling the assembly to bone. The wall thickness of the exchange cannula may be eccentric, to accommodate the drill wire lumen within the exchange cannula wall. A tensioning handle may be carried over the exchange cannula, for engaging adjacent tissue. The exchange cannula may have a proximal “T” handle. An exchange rod is movably positionable within the central lumen of the exchange cannula.