Transpedicular Intervertebral Disk Access Methods and Devices

Abstract

Methods and devices for treating diseases and conditions that change the spacial relationship between the vertebral bodies and the intervertebral disks, or that cause instability of the vertebral column, or both, and a method and devices that allow the surgeon to access the intervertebral space to restore a more normal three-dimensional configuration of the space, with or without additionally fusing two adjacent vertebrae.

1 . A blade assembly for use with a cutting device, the blade assembly comprising:
 a blade comprising a flexible portion that is capable of being deformed to enable the blade to be placed in a retracted position;   a blade wing, attached to the blade, wherein the blade wing is oriented at an angle to the blade and facilitates passage of the blade though a sheath; and   a connection portion for connecting the blade assembly to a shaft.   
     
     
         2 . The blade assembly of  claim 1  wherein the blade, blade wing and connection portion are integrally formed from a flexible material. 
     
     
         3 . The blade assembly of  claim 2  wherein the flexible material further comprises nitinol. 
     
     
         4 . The blade assembly of  claim 1  wherein the blade wing is oriented at an angle substantially in the range of 130° to 140°. 
     
     
         5 - 10 . (canceled) 
     
     
         11 . A cutting device for use in percutaneous procedures, the device comprising:
 a cutting head extending from a shaft, the cutting head comprising:
 a first blade extending from a central portion of the cutting head, the first blade movable between a first insertion configuration and a first cutting configuration, wherein the first blade extends generally along a longitudinal axis of the shaft in the first insertion configuration and extends generally perpendicular to the longitudinal axis in the first cutting configuration; 
 a second blade extending from the central portion of the cutting head, the second blade movable between a second insertion configuration and a second cutting configuration, wherein the second blade extends generally along the longitudinal axis of the shaft in the second insertion configuration and extends generally perpendicular to the longitudinal axis opposite the first blade in the second cutting configuration; 
 a first wing extending from a distal end of the first blade at a first oblique angle relative to the first blade such that the first wing extends at an oblique angle with respect to the longitudinal axis of the shaft when the first blade is in both the first insertion configuration and the first cutting configuration, the first wing extending distally beyond the distal end of the first blade and having a distal most tip pointing inwardly toward the longitudinal axis when the first blade is in the first insertion configuration; 
 a second wing extending from a distal end of the second blade at a second oblique angle relative to the second blade such that the second wing extends at an oblique angle with respect to the longitudinal axis of the shaft when the second blade is in both the second insertion configuration and the second cutting configuration, the second wing extending distally beyond the distal end of the second blade and having a distal most tip pointing inwardly toward the longitudinal axis when the second blade is in the second insertion configuration; 
 a first transition portion defined by a first interface between the distal end of the first blade and a proximal end of the first wing, the first transition portion being an arcuate bend such that the distal end of the first blade, the first transition portion, and the proximal end of the first wing have a substantially constant thickness; and 
 a second transition portion defined by a second interface between the distal end of the second blade and a proximal end of the second wing, the second transition portion being an arcuate bend such that the distal end of the second blade, the second transition portion, and the proximal end of the second wing have a substantially constant thickness. 
   
     
     
         12 . The device of  claim 11  wherein the first and second blades, and the first and second wings are integrally formed from a resiliently flexible material. 
     
     
         13 . The device of  claim 12 , wherein the resiliently flexible material comprises nitinol. 
     
     
         14 . The device of  claim 13 , wherein the first oblique angle is between about 130° and about 140°. 
     
     
         15 . The device of  claim 14 , wherein the second oblique angle is between about 130° and about 140°. 
     
     
         16 . The device of  claim 15 , wherein the flexible section of the shaft comprises a plurality of slots formed in the shaft. 
     
     
         17 . The device of  claim 11 , wherein the first and second blades are biased towards the first and second cutting configurations. 
     
     
         18 . The device of  claim 17 , wherein the first and second blades are substantially symmetrical about the longitudinal axis. 
     
     
         19 . The device of  claim 11 , wherein the first and second blades are asymmetrical about the longitudinal axis. 
     
     
         20 . A cutting device for use in percutaneous procedures, the device comprising:
 a cutting head extending from a distal portion of a shaft, the cutting head comprising:
 a first blade having a main portion adjacent the shaft and a wing portion extending from the main portion and spaced from the shaft, the first blade having a bend between the main portion and the wing portion such that the wing portion extends at an oblique angle relative to the main portion, the first blade having opposing planar surfaces and a constant thickness between the opposing planar surfaces across the main and wing portions; and 
 a second blade having a main portion adjacent the shaft and a wing portion extending from the main portion and spaced from the shaft, the second blade having a bend between the main portion and the wing portion such that the wing portion extends at an oblique angle relative to the main portion, the second blade having opposing planar surfaces and a constant thickness between the opposing planar surfaces across the main and wing portions; 
 the first and second blades movable between an insertion configuration and a cutting configuration, where the first and second blades extend generally along a longitudinal axis of the shaft in the insertion configuration and extend generally perpendicular to the longitudinal axis in the cutting configuration. 
   
     
     
         21 . The device of  claim 20 , wherein the first and second blades extend substantially symmetrically relative to the longitudinal axis. 
     
     
         22 . The device of  claim 20 , wherein the wing portions of the first and second blades extend at an oblique angle between about 130° and about 140° relative to the main portions of the first and second blades, respectively. 
     
     
         23 . The device of  claim 20 , wherein a majority of the first blade has a constant width across the main and wing portions in a direction perpendicular to the thickness between the opposing planar surfaces. 
     
     
         24 . The device of  claim 20 , wherein the first and second blades comprise a resiliently flexible material biased towards the cutting configuration. 
     
     
         25 . The device of  claim 24 , wherein the resiliently flexible material comprises nitinol. 
     
     
         26 . The device of  claim 20 , wherein the wing portions of the first and second blades each have a distal most tip pointing inwardly toward the longitudinal axis when the first and seconds blade are in the insertion configuration.