Spinal stabilization implant and method of application

Abstract

Vertebra bodies in the human spine are stabilized through the use of minimally invasive surgery for the implantation of an elongate implant plate assembly having spaced first and second screw receiving socket elements which are configured for respective attachment to first and second spaced vertebra with the aid of bone fixation screws and these elements are slidably received with respect to each other for adjustably changing the distance between the screw receiving socket elements. A lock assembly is also provided for selectively locking the first and second screw receiving elements from further relative sliding. An elongate insertion tool is releaseably secured to the plate assembly, and the insertion tool is configured for manipulating the plate assembly as a whole and for remotely manipulating the screw receiving socket elements for adjusting the distance therebetween. The plate assembly is inserted through an incision and manipulated and advanced with the insertion tool to provide minimally invasive insertion, and after fixation of the implant assembly with bone fixation screws is further utilized by remote manipulation to adjust the degree of compression on the vertebrae, and thereafter the implant is locked in position to prevent further relative movement between the screw receiving elements of the plate assembly.

1 . A minimally invasive surgical implant system comprising: 
 a plate assembly having spaced distal and proximal screw receiving elements movable with respect to each other for adjustably changing the distance between elements; and    an elongate insertion tool having distal and proximal ends and releaseably connected at said distal end thereof to said plate assembly for manipulating the plate assembly and operable for remotely adjusting the distance between said elements.    
   
   
       2 . The implant system of  claim 1 , said plate assembly having proximal and distal ends and said insertion tool is releaseably connected to said proximal end of said plate assembly whereby said tool and plate assembly extend together end to end.  
   
   
       3 . The implant system of  claim 2 , said plate assembly including a lock assembly for selectively locking said screw receiving elements from further relative movement therebetween.  
   
   
       4 . The implant system of  claim 3 , said screw receiving elements each having a screw head socket bowl for receiving the head of a bone fixation screw with mating intimacy, and a passage in the bottom of each bowl for passage of the shank of a bone fixation screw.  
   
   
       5 . The implant system of  claim 4 , including an open ended guide wire capture slot in the distal end of said assembly which communicates with said distal bowl passage.  
   
   
       6 . The implant system of  claim 2 , wherein the distal end of said assembly has a leading transverse edge which is tapered for permitting the plate assembly to nestle next to a facet joint without impeding the joint's functional movement.  
   
   
       7 . The implant system of  claim 4 , said proximal screw receiving element slidable along an arm portion of said plate assembly, said lock assembly including a slot in said arm portion underlying said proximal bowl for receiving the shank of a fixation screw therethrough and therealong at desired positions, said slot dimensioned for seating portions of the head of a bone fixation screw protruding from said proximal bowl passage.  
   
   
       8 . The implant system of  claim 7 , wherein edges of said slot include an aligned series of adjacent screw head seat depressions for selectively seating portions of the head of a bone fixation screw.  
   
   
       9 . The implant system of  claim 1  wherein the distal end of said insertion tool is connected to said plate assembly whereby said plate assembly may be remotely oriented by manipulation from said tool proximal end from a reduced profile orientation to an increased profile orientation with respect to the distal end of said tool.  
   
   
       10 . The implant system of  claim 9 , said plate assembly being elongated and having distal and proximal ends, and the distal end of said insertion tool releaseably and pivotally connected to said proximal screw receiving element, said insertion tool having a tubular probe housing with opposed anterior and posterior probe walls covering respectively the distal and proximal ends of said plate assembly when said plate assembly is in the reduced profile orientation, said insertion tool operable by manipulation from its proximal end to orient said plate assembly from the reduced profile orientation to the increased profile orientation while simultaneously expanding said probe walls apart in the direction of elongation of said plate assembly.  
   
   
       11 . The implant system of  claim 10 , said insertion tool having guide means for guiding said proximal screw receiving element from the reduced profile orientation to the increased profile orientation whereby said proximal screw receiving element in the increased profile orientation is positioned for screw access from the proximal end of said insertion tool through the hollow interior of said tubular probe housing.  
   
   
       12 . The implant system of  claim 1   1 , a distal end of said posterior probe wall being engageable with the proximal end of said plate assembly for adjusting the distance between said screw receiving elements when said plate assembly is in the increased profile orientation by moving said posterior probe wall.  
   
   
       13 . The implant system of  claim 12 , said plate assembly including a lock assembly for selectively locking said screw receiving elements from further relative movement therebetween.  
   
   
       14 . The implant system of  claim 13 , wherein the distal end of said assembly has a leading transverse edge which is tapered for permitting said plate assembly to nestle next to a facet joint without impeding the joint's functional movement.  
   
   
       15 . The implant system of  claim 13 , wherein said screw receiving elements have a screw head socket bowl for receiving the head of a bone fixation screw with mating intimacy, and a passage in the bottom of each bowl for passage of the shank of a bone fixation screw.  
   
   
       16 . The implant system of  claim 15 , including an open ended guide wire capture slot in the distal end of said plate assembly which communicates with said distal bowl passage.  
   
   
       17 . The implant system of  claim 15 , said proximal screw receiving element slidable along an arm portion of said plate assembly, said lock assembly including a slot in said arm portion underlying said proximal bowl for receiving the shank of a fixation screw therethrough and therealong at desired positions, said slot dimensioned for seating portions of the head of a bone fixation screw protruding from said proximal bowl passage.  
   
   
       18 . The implant system of  claim 17 , edges of said slot including an aligned series of adjacent screw head seat depressions for selectively seating portions of the head of a bone fixation screw.  
   
   
       19 . A minimally invasive surgical implant system comprising: 
 an implant having a longitudinal axis and positionable adjacent surgical space associated with a spinal column of a patient;    an insertion tool including an articulating implant holder adjacent a distal end thereof which is releaseably engagable to said implant whereby said implant is thereby moveable with respect to a longitudinal axis of said insertion tool from a reduced profile orientation to an increased profile orientation, said insertion tool operable to move said implant laterally relative to the longitudinal axis of said insertion tool and in the direction of the longitudinal axis of said implant when positioned in the increased profile orientation.    
   
   
       20 . The minimally invasive surgical implant system of  claim 19 , said insertion tool including an expandable housing at its distal end for expanding surrounding tissue in the direction of the longitudinal axis of said implant while said implant is being oriented to the increased profile orientation.  
   
   
       21 . A method for positioning an implant along a spinal column of a patient, comprising; 
 accessing the spinal column through a minimally invasive access path through skin and tissue of the patient;    securing the implant on an insertion tool with a longitudinal axis of said implant extending generally in the direction of said access path in a reduced profile orientation relative to said insertion tool;    positioning said implant through said access path with said insertion tool to a location adjacent the spinal column;    remotely pivotally said implant with said insertion tool to an increased profile orientation; and    laterally moving said implant with and relative to said insertion tool in the direction of the longitudinal axis of said implant to a desired orientation along the spinal column.    
   
   
       22 . The method of  claim 19 , including expanding said access path in the direction of the longitudinal axis of said implant while orienting said implant to the increased profile orientation.  
   
   
       23 . A method of stabilizing spaced vertebra bodies in the human spine with minimally invasive surgery, comprising the steps of: 
 providing an elongate implant plate assembly having proximal and distal ends with first and second screw receiving socket elements configured for respective attachment to first and second spaced vertebra with the aid of bone fixation screws, said elements slidably received with respect to each other for adjustably changing the distance between said screw receiving socket elements, and having a lock assembly for selectively locking said first and second screw receiving socket elements from further relative sliding, said second socket element positioned adjacent the proximal end of said plate assembly;    additionally providing an elongate insertion tool which is releaseably securable to said plate assembly and configured for manipulating said plate assembly and for remotely manipulating said socket elements for adjusting the distance therebetween;    securing said insertion tool to said plate assembly for manipulation thereof;    making an incision adjacent said second vertebra for inserting said implant plate assembly;    inserting said plate assembly into said incision, distal end first, and positioning said second screw receiving socket element over said second vertebra by manipulation with said insertion tool;    extending said distal end of said plate assembly relative to said second screw receiving socket element and thereby positioning said first screw receiving socket over said first vertebra by remote manipulation with said insertion tool;    securing said distal and proximal ends to said first and second vertebra with bone fixation screws received in said first and second screw receiving socket elements;    adjusting the distance between said first and second socket elements to a desired degree by remote manipulation of said socket elements with said insertion tool for thereby adjusting the distance between the two secured vertebra;    locking said socket elements from further relative motion with said lock assembly; and    detaching said insertion tool from said implant plate assembly.    
   
   
       24 . The method of  claim 23 , including the step of guiding the manipulations of said implant plate assembly relative to said vertebra by using fluoroscopy.  
   
   
       25 . The method of  claim 24 , including the steps of pre-penetrating said first and second vertebra for thereby providing guide channels for said screws, positioning guide wires in said guide channels prior to the steps of securing, and securing by using self tapping cannulated pedicle screws received over and guided by said wires, and removing said guide wires after the step of securing.  
   
   
       26 . The method of  claim 25 , wherein the step of positioning said distal end includes providing an open ended guide slot in the leading edge of said distal end which provides access to a distal screw securement passage in said first screw receiving socket element, and guiding the extension and positioning of said distal end by capturing said distal guide wire in said slot while extending said distal end until said distal passage of said first socket element is centered over said distal guide wire.  
   
   
       27 . The method of  claim 24 , wherein the step of locking said socket elements is accomplished by fully securing said proximal second screw.  
   
   
       28 . An implant plate assembly for stabilization of the spine, comprising: 
 a first screw receiving socket element at a distal end of said assembly and configured with a screw shank passage and a screw head seat for attachment to a vertebra with the aid of a bone fixation screw;    an elongate arm extending proximally from said first socket element and having an elongate through slot therealong;    a second screw receiving socket element also configured with a screw shank passage and a screw head seat, and slidably received over said arm with its passage aligned over said slot for receiving the shank of a fixation screw therethrough for attachment to a vertebra;    said second socket element and said slot configured and dimensioned whereby portions of a screw head of a fixation screw seated in said second socket element protrude through said second socket element passage and engage edges of said slot for clamping said second socket element to said arm when said screw is fully secured in a vertebra.    
   
   
       29 . The implant plate assembly of  claim 28 , edges of said slot including a series of adjacent screw head seat depressions for selectively seating portions of the head of a bone fixation screw.  
   
   
       30 . The implant plate assembly of  claim 29 , a cap buttress nut threadably received in said second socket element over said screw head for engaging and covering said screw head.  
   
   
       31 . The implant plate assembly of  claim 30 , said nut having bottom protuberances for engaging said screw head as a lock.  
   
   
       32 . An implant for stabilization of the spine, comprising: 
 an elongate implant plate assembly having distal and proximal ends configured for respective attachment to first and second spaced vertebra with the aid of bone fixation screws;    said plate assembly including first and second screw receiving elements slidably received with respect to each other for adjustably changing the distance between said elements;    a lock assembly for selectively locking said first and second elements from further relative movement therebetween; and    said first and second screw receiving elements each having a screw head socket bowl for receiving the head of a bone fixation screw with mating intimacy and a passage in the bottom of each bowl for passage of the shank of a bone fixation screw;    said second screw receiving element slidable along an arm portion of said plate assembly, said lock assembly including a slot in said arm portion underlying said passage for said second bowl for receiving the shank of a fixation screw therethrough and therealong at desired positions, and said passage for said second bowl and said slot configured and dimensioned whereby portions of the head of a fixation screw received in said second bowl protrude through said passage for said second bowl to engage edges of said slot and thereby clamp said second screw receiving element to said plate assembly when said fixation screw is fully secured to a vertebra.    
   
   
       33 . The implant of  claim 32 , including an open ended guide wire capture slot in said distal end which communicates with said first bowl passage.  
   
   
       34 . The implant of  claim 32 , including locking caps configured and dimensioned for closing off said bowls with bone fixation screw heads seated in said bowls.  
   
   
       35 . The implant of  claim 34 , said locking caps threadably received in said bowls and having bottom protuberances for engaging said screw heads as a lock.  
   
   
       36 . The implant of  claim 32 , wherein said distal end has a leading transverse edge which is tapered.  
   
   
       37 . The implant of  claim 32 , wherein said plate assembly is longitudinally curved to mate a specific lordotic curve.  
   
   
       38 . The implant of  claim 32 , wherein said slot is dimensioned and contoured for seating portions of the head of a bone fixation screw protruding from said second bowl.  
   
   
       39 . The implant of  claim 38 , edges of said slot including an aligned series of adjacent screw head seat depressions for selectively seating portions of the head of a bone fixation screw at different positions along said slot.