Spinal surgery instruments and methods

Abstract

Instruments and methods for insertion of one or more spinal implants into an intervertebral space between opposing vertebral bodies are disclosed. Instruments according to the invention include a guide for preparing a spinal fusion implant site, a guide starter, implant depth gauges, reamers, taps and implant drivers. The instruments and methods disclosed provide improved visualization of the surgical field and enhanced precision of placement of spinal fusion implants between vertebral bodies.

What is claimed is:  
     
         1 . A guide for preparing a spinal fusion implant site between opposing vertebral bodies, the guide comprising: 
 a ring wall, said ring wall having a first end, a second end and a first internal ring wall forming a first lumen having a first lumen diameter;    said ring wall having a first ring wall length (R L1 ) extending from said first end to said second end of said ring wall;    said guide having an aspect ratio of less than about 4:1;    a first projection extending from said first end of said ring wall, said projection having a first projection length (L P1 ) at least as great as said first ring wall length.    
     
     
         2 . A guide according to  claim 1  wherein said ring wall is complete.  
     
     
         3 . A guide according to  claim 1  wherein said first projection length is greater than said first ring wall length.  
     
     
         4 . A guide according to  claim 1  having a ratio of L P :R L  of about 1:4 to 3:1.  
     
     
         5 . A guide according to  claim 1  having a ratio of L P :R L  of about 1:4 to 1:2.5.  
     
     
         6 . A guide according to  claim 4  wherein said aspect ratio is about 0.5:1 to 3:1.  
     
     
         7 . A guide according to  claim 1  wherein said ring wall has a second ring wall length extending from said first end to said second end of said ring wall, said second ring wall length being less than said first ring wall length.  
     
     
         8 . A guide according to  claim 1  having a second projection extending from said first end of said ring wall.  
     
     
         9 . A guide according to  claim 8  wherein said second projection has a second projection length (L P2 ) such that a ratio of L P2 :R L1  is about 1:1 to 1:2.5.  
     
     
         10 . A guide according to  claim 9  wherein said first and second projections are co-linear with said first ring wall.  
     
     
         11 . A guide according to  claim 7  further comprising an anchoring arrangement at said first end of said ring wall.  
     
     
         12 . A guide according to  claim 11  wherein said anchoring arrangement comprises at least one tooth.  
     
     
         13 . A guide according to  claim 11  wherein said anchoring arrangement comprises a plurality of teeth.  
     
     
         14 . A guide according to  claim 1  further comprising a handle.  
     
     
         15 . A guide according to  claim 14  wherein said handle is selectively removable from said ring wall.  
     
     
         16 . A guide according to  claim 7  wherein said first end of said ring wall is in a first plane and said second end of said ring wall is in a second plane and said first plane and said second plane form an angle therebetween of about 0° to 30°.  
     
     
         17 . A guide according to  claim 1  wherein said ring wall further includes a second internal ring wall forming a second lumen having a second lumen diameter.  
     
     
         18 . A guide according to  claim 17  wherein said first lumen diameter and said second lumen diameter are equal.  
     
     
         19 . A guide according to  claim 17  wherein said first projection extending from said first end of said ring wall extends between said first and second lumens.  
     
     
         20 . A guide according to  claim 1  having a second projection extending from said first end of said ring wall, each of said first and second projections being tapered.  
     
     
         21 . A surgical instrument comprising: 
 a tubular sleeve comprising an outer wall surrounding a lumen and having a first end and a second end    a shaft sized to pass into said lumen of said tubular sleeve and comprising 
 a working end which can protrude a plurality of predetermined distances beyond said first end of said tubular sleeve;  
 a depth adjustment arrangement for selectively controlling said predetermined distances said working end protrudes beyond said first end of said tubular sleeve.  
   
     
     
         22 . The surgical instrument according to  claim 21  wherein said depth adjustment arrangement comprises a plurality of stops positioned on said shaft and incrementally spaced a distance from said working end of said shaft, each stop corresponding to one of said predetermined distances said working end protrudes beyond said first end of said tubular sleeve.  
     
     
         23 . The surgical instrument according to  claim 22  wherein said shaft is circular in transverse cross section and said stops are circumferentially positioned around said shaft.  
     
     
         24 . The surgical instrument according to  claim 23  wherein said stops are positioned in a stair-step arrangement around said shaft.  
     
     
         25 . The surgical instrument according to  claim 24  wherein each stop is associated with a groove which is configured to interdigitate with a pin protruding into said lumen of said tubular sleeve near said second end of said tubular sleeve.  
     
     
         26 . The surgical instrument according to  claim 24  wherein said predetermined distances are selectively controlled by moving said tubular sleeve towards said working end of said shaft and rotating said tubular sleeve.  
     
     
         27 . The surgical instrument according to  claim 21  wherein said outer wall of said tubular sleeve includes an exterior surface having at least two different cross sectional dimensions forming a lip near said first end of said tubular sleeve.  
     
     
         28 . The surgical instrument according to  claim 26  wherein said tubular sleeve is biased relative to said shaft.  
     
     
         29 . The surgical instrument according to  claim 28  wherein said bias is provided by a helical spring.  
     
     
         30 . The surgical instrument according to  claim 21  wherein said working end is a reamer.  
     
     
         31 . The surgical instrument according to  claim 21  wherein said working end is a tap.  
     
     
         32 . A kit for placement of a spinal implant between opposing vertebral bodies, the kit comprising: 
 (a) a first guide for preparing a spinal fusion implant site between said opposing vertebral bodies, said first guide comprising: 
 a first ring wall, said first ring wall having a first end, a second end and a first internal ring wall forming a first lumen having a first lumen diameter;  
 said first ring wall having a first ring wall length extending from said first end to said second end of said first ring wall;  
 said guide having an aspect ratio of less than about 4:1;  
 a first projection extending from said first end of said first ring wall, said projection having a first projection length at least as great as said first ring wall length; and  
   (b) a guide starter, said guide starter comprising: 
 a first guide end, said first guide end having a first guide diameter sized for insertion within said first lumen diameter and a second guide diameter which is greater than said first guide diameter.  
   
     
     
         33 . A kit according to  claim 32  further comprising a reamer.  
     
     
         34 . A kit according to  claim 33  wherein the reamer is adjustable.  
     
     
         35 . A kit according to  claim 32  further comprising, a second guide for preparing a spinal fusion implant site between said opposing vertebral bodies, said second guide comprising: 
 a second ring wall, said second ring wall having a first end, a second end and a second internal ring wall forming a second lumen having a second lumen diameter, said second lumen diameter different from said first lumen diameter.  
 
     
     
         36 . A kit according to  claim 35  wherein said guide starter comprises: 
 a second guide end longitudinally spaced from said first guide end along a shaft, said second guide end having a third guide diameter sized for insertion within said second lumen diameter and a fourth guide diameter which is greater than said second lumen diameter.  
 
     
     
         37 . A kit according to  claim 32  wherein said first ring wall further includes a second internal ring wall forming a second lumen having a second lumen diameter.  
     
     
         38 . A kit according to  claim 37  wherein said first lumen diameter is equal to said second lumen diameter.  
     
     
         39 . A method for preparing a site for implanting a spinal implant into a disc space between adjacent first and second vertebral bodies the method comprising: 
 distracting said first and second adjacent vertebrae;    applying a guide over said disc space between distracted first and second adjacent vertebrae, said guide comprising: 
 (i) a ring wall, said ring wall having a first end, a second end and a first internal ring wall forming a first lumen having a first lumen diameter;  
 (ii) said ring wall having a first ring wall length extending from said first end to said second end of said ring wall;  
 (iii) said guide having an aspect ratio of less than about 4:1;  
   passing a reamer through said internal ring wall to said disc space and reaming a site for implanting said spinal implant.    
     
     
         40 . A method according to  claim 39  wherein said guide further comprises a first projection extending from said first end of said ring wall, said projection having a first projection length at least as great as said first ring wall length.  
     
     
         41 . A method according to  claim 39  further comprising a step of: 
 removing said guide; and  
 inserting said implant into said implant site.  
 
     
     
         42 . A method according to  claim 41  wherein said implant is inserted into said implant site before said guide is removed.  
     
     
         43 . An adjustable guide tube comprising: 
 a guide housing having a distal end and a proximal end, said proximal end including a proximal cutout having a proximal shoulder and a plurality of grooves and stops;    an adjustable sleeve having a proximal rim and a distal ridge forming a distal shoulder and a pin protruding from an inner surface of said adjustment sleeve; and    a biasing arrangement to bias said proximal rim away from said distal end.