Transcorporeal spinal decompression and repair system

Abstract

A system and method are provided for making an access channel through a vertebral body to access a site of neural compression, decompressing it, and repairing the channel to restore vertebral integrity. System elements include an implantable vertebral plate, a guidance device for orienting bone cutting tools and controlling the path of a cutting tool, a bone cutting tool to make a channel in the vertebral body, a tool for opening or partially-resecting the posterior longitudinal ligament of the spine, a tool for retrieving a herniated disc, an implantable device with osteogenic material to fill the access channel, and a retention device that lockably-engages the bone plate to retain it in position after insertion. System elements may be included in a surgery to decompress an individual nerve root, the spinal cord, or the cauda equina when compressed, for example, by any of a herniated disc, an osteophyte, a thickened ligament arising from degenerative changes within the spine, a hematoma, or a tumor.

What is claimed is: 
     
         1 . A surgical system to form an access channel through a vertebral body, the channel having an anterior surface entry and a posterior surface opening, the system comprising:
 a bone cutting tool with a cutting element; and   an integrated device comprising a bone plate portion and trajectory control sleeve portion,   the bone plate portion configured to be secured to an anterior surface of the vertebral body,   the trajectory control sleeve portion having a cylinder configured to receive at least a portion of the bone cutting tool, the integrated device configured to guide the bone cutting tool to form the access channel with a prescribed trajectory from the anterior entry to the prescribed posterior opening.   
     
     
         2 . The surgical system of  claim 1  wherein the bone plate portion includes openings to accommodate fixation elements to secure the bone plate portion to the anterior surface of the vertebral body. 
     
     
         3 . The surgical system of  claim 1  wherein the trajectory control sleeve portion is configured to direct the bone cutting tool on the prescribed trajectory, the prescribed trajectory having an angle according to a cranio-caudal axis and a medial lateral axis with respect to a reference plane tangential to the access channel entry on the anterior surface of the vertebral body. 
     
     
         4 . The surgical system of  claim 3  wherein the angle is a compound angle. 
     
     
         5 . The surgical system of  claim 1  wherein the bone plate portion provides a reference surface and wherein the trajectory control sleeve portion may be configured with a range of angles formed with respect to the surface of the bone plate portion on two axes, a cranio-caudal axis and a medial lateral axis, the range of the angles varying between about 1 degree and about 30 degrees from a perpendicular angle. 
     
     
         6 . The surgical system of  claim 5  wherein the range of the angle varies between about 10 degrees and about 30 degrees from the perpendicular angle. 
     
     
         7 . The surgical system of  claim 1  wherein the trajectory control sleeve portion includes a contact surface for engaging a corresponding surface on the bone cutting tool, the surfaces configured so as to limit the penetration of the cutting tool into the vertebral body to a prescribed depth. 
     
     
         8 . The surgical system of  claim 1  wherein the posterior surface of the bone plate portion includes one or more penetrating elements configured to impinge into the vertebral bone tissue. 
     
     
         9 . The surgical system of  claim 1  wherein the bone plate portion includes an anatomically-orienting feature to establish the position of the bone plate portion relative to the medial centerline of the vertebral body. 
     
     
         10 . The surgical system of  claim 1  wherein the bone-cutting tool is any of a drill, a ream, a core cutter or a trephine. 
     
     
         11 . The surgical system of  claim 10  wherein the cutting element of the bone-cutting tool has a cutting diameter between about 5 mm and about 7 mm. 
     
     
         12 . The surgical system of  claim 1  further comprising an implantable bone repair device having an external geometry complementary to the internal geometry of the access channel. 
     
     
         13 . The surgical system of  claim 12  wherein the bone repair device is sized to be insertable through an opening of the bone plate portion, the opening being sized to receive the bone cutting element. 
     
     
         14 . The surgical system of  claim 12  wherein the bone repair device includes a bio-compatible material. 
     
     
         15 . The surgical system of  claim 12  wherein the bone repair device includes a bio-absorbable material. 
     
     
         16 . The surgical system of  claim 12  wherein the bone repair device includes an osteogenic agent. 
     
     
         17 . The surgical system of  claim 12  wherein bone repair device includes receiving features in or on its anterior surface configured to accommodate the attachment of an insertion tool. 
     
     
         18 . The surgical system of  claim 12  wherein the bone repair device comprises a porous cage with a porosity sufficient to permit through movement of blood and bone cells. 
     
     
         19 . The surgical system of  claim 18  wherein the composition of the porous cage comprises any of a polymer, a metal, metallic alloy, or a ceramic. 
     
     
         20 . The surgical system of  claim 19  wherein the polymer of the composition may include polyetheretherketone (PEEK), PEEK-reinforced carbon fiber, or hydroxyapatite-reinforced PEEK. 
     
     
         21 . The surgical system of  claim 18  wherein the porous cage device includes a closeable opening through which bone material may be passed. 
     
     
         22 . The surgical system of  claim 18  wherein the porous cage device includes a closeable cap configured to increase pressure within the cage as the cap is closed. 
     
     
         23 . The surgical system of  claim 18  wherein the porous cage device includes a minimally compressive internal element adapted to enhance compressive force applied to contents of the porous cage upon application of compressive force to the cage. 
     
     
         24 . The surgical system of  claim 1  further comprising a trajectory and depth visualization device. 
     
     
         25 . The surgical system of  claim 24  wherein the trajectory and depth visualization device includes a radio-opaque feature to allow confirmation of the location of the bone plate portion device on the appropriate vertebral body and to facilitate the extrapolation of the projected trajectory of the bone cutting tool using a radiographic image. 
     
     
         26 . The surgical system of  claim 24  wherein the trajectory and depth visualization device includes visual markings to indicate a distance from a point of contact with the vertebral body and cutter penetration control feature on the bone cutter guide device. 
     
     
         27 . A surgical system to form an access channel through a single vertebral body overlaying a site in need of a medical procedure adjacent a spinal cord in advance of performing the procedure through the access channel, the channel having an anterior surface entry and a posterior surface opening, the system comprising:
 an integrated device comprising a bone plate portion and a trajectory control sleeve portion; and   a bone cutting tool,   wherein the bone plate portion of the integrated device comprises a curved surface configured to contact an anterior surface of a single vertebral body and to be temporarily secured to the anterior surface of the vertebral body, wherein the trajectory control sleeve portion of the integrated device comprises a cylinder configured to receive at least a portion of the bone cutting tool, wherein the integrated device and the bone cutting tool are configured to cooperate to form a single access channel with a prescribed trajectory from an anterior entry to a prescribed posterior opening on a posterior surface of the vertebral body adjacent a spinal cord, the anterior entry of the single access channel having a center that is generally at a mid-point on a cranio-caudal length of the vertebral body and generally offset from a medio-lateral mid-point of the vertebral body, wherein the single access channel to be formed has a circular cross-section along a single, straight axis from the anterior entry in a posterior, caudal and lateral direction to the prescribed posterior opening, the prescribed posterior opening being located at or adjacent to the base of the posterior surface of the single vertebral body, the single access channel having an angle in the cranio-caudal direction of between about 1 degree and about 30 degrees from perpendicular to the anterior surface at the anterior entry, the single access channel having an angle in the medio-lateral direction of between about 1 degree and about 30 degrees from perpendicular to the anterior surface at the anterior entry, the single access channel having a diameter of between about 5 mm and about 8 mm, wherein a portion of the cutting tool is configured to contact a portion of the integrated device to precisely limit the penetration of the cutting tool into the vertebral body to a prescribed depth.