Spinous process implants and associated methods

Abstract

The present invention provides spinous process implant and associated methods. In one aspect of the invention the implant limits the maximum spacing between the spinous processes. In another aspect of the invention, a spacer has at least one transverse opening to facilitate tissue in-growth. In another aspect of the invention, an implant includes a spacer and separate extensions engageable with the spacer. The spacer is provided in a variety of lengths and superior to inferior surface spacings. In another aspect of the invention, an implant includes a spacer and a cerclage element offset from the midline of the spacer in use so that the spacer defines a fulcrum and the cerclage element is operative to impart a moment to the vertebrae about the spacer. In another aspect of the invention, instrumentation for inserting the implant is provided. In other aspects of the invention, methods for treating spine disease are provided.

1 - 15 . (canceled) 
     
     
         16 . An implant for placement between spinous processes of adjacent vertebrae of a spine, the implant comprising:
 a cylindrical hollow spacer with a first end, a second end, and a longitudinal axis extending from the first end to the second end, the spacer comprising superior and inferior surfaces operable to abut the spinous processes and maintain minimum spacing between spinous processes;   a first extension integral with and projecting from the first end of the cylindrical hollow spacer transverse to the longitudinal axis to lie generally alongside the spinous processes of adjacent vertebrae, the first extension including a first lobe extending superiorly long a first extension axis and a second lobe extending inferiorly long a second extension axis, wherein the first extension axis is offset anteriorly from the second extension axis; and   a second extension slidably engageable with the cylindrical hollow spacer opposing the first extension, the second extension including a third lobe extending superiorly long a third extension axis and a fourth lobe extending inferiorly long a fourth extension axis, wherein the third extension axis is offset anteriorly from the fourth extension axis, and wherein the third lobe aligns opposite the first lobe engaging a first spinous process of a first vertebrae and the fourth lobe aligns opposite the second lobe engaging a second spinous process of a second vertebrae.   
     
     
         17 . The implant of  claim 16 , wherein the cylindrical hollow spacer includes at least one channel running along a length of the spacer aligned with the longitudinal axis and exposing an inner portion of the cylindrical hollow spacer to facilitate tissue in-growth into the cylindrical hollow spacer. 
     
     
         18 . The implant of  claim 17 , wherein the second extension includes a body with a c-shaped aperture for receiving the cylindrical hollow spacer. 
     
     
         19 . The implant of  claim 18 , wherein the c-shaped aperture includes a tab extending radially inward and engaging the at least one channel running along the length of the cylindrical hollow spacer. 
     
     
         20 . The implant of  claim 16 , wherein the second extension includes set screw adapted to engage a posterior side of the cylindrical hollow spacer. 
     
     
         21 . The implant of  claim 16 , wherein the first lobe and third lobe are offset anteriorly relative to the second lobe and the fourth lobe to allow the extensions of multiple implants to be interleaved on common interspinous processes. 
     
     
         22 . The implant of  claim 16 , wherein the first extension includes at least one fastener adapted to engage at least one of the spinous processes to fix the cylindrical hollow spacer between the spinous processes. 
     
     
         23 . 8. The implant of  claim 16 , wherein the second extension includes at least one fastener adapted to engage at least one of the spinous processes to fix the cylindrical hollow spacer between the spinous processes. 
     
     
         24 . The implant of  claim 16 , wherein the first extension and the second extension both include a plurality of fasteners, wherein a first portion of the plurality of fasteners on the first extension are adapted to be offset relative to a second portion of the plurality of fasteners on the second extension when the plurality of fasteners are engaged with the spinous processes. 
     
     
         25 . An implant system for placement between spinous processes of adjacent vertebrae of a spine, the system comprising:
 a first implant spanning a first spinous process on a first vertebrae and a second spinous process on a second vertebrae, the first implant comprising:
 a first spacer with a first end, a second end, a hollow cylindrical body, and a longitudinal axis extending from the first end to the second end, the spacer comprising superior and inferior surfaces operable to abut the first spinous process and the second spinious process to maintain minimum spacing between the first spinous process and the second spinous process; 
 a first extension integral with and projecting from the first end of the first spacer transverse to the longitudinal axis, the first extension including a first lobe extending superiorly long a first extension axis to engage the first spinous process and a second lobe extending inferiorly long a second extension axis to engage the second spinous process, wherein the first extension axis is offset anteriorly from the second extension axis; and 
 a second extension slidably engageable with the spacer opposing the first extension, the second extension including a third lobe extending superiorly long a third extension axis to engage the first spinous process opposite the first lobe and a fourth lobe extending inferiorly long a fourth extension axis to engage the second spinous process opposite the second lobe; and 
   a second implant spanning the second spinous process on the second vertebrae and a third spinous process on a third vertebrae, the second implant comprising:
 a second spacer with a first end, a second end, a hollow cylindrical body, and a second longitudinal axis extending from the first end to the second end, the second spacer comprising superior and inferior surfaces operable to abut the second spinous process and the third spinious process to maintain minimum spacing between the second spinous process and the third spinous process; 
 a third extension integral with and projecting from the first end of the second spacer transverse to the second longitudinal axis, the third extension including a fifth lobe extending superiorly long a fifth extension axis to engage the second spinous process adjacent to the second lobe and a sixth lobe extending inferiorly long a sixth extension axis to engage the third spinous process, wherein the fifth extension axis is offset anteriorly from the sixth extension axis; and 
 a fourth extension slidably engageable with the second spacer opposing the third extension, the fourth extension including a seventh lobe extending superiorly long a seventh extension axis to engage the second spinous process adjacent the fourth lobe and a eighth lobe extending inferiorly long an eighth extension axis to engage the third spinous process opposite the sixth lobe. 
   
     
     
         26 . The implant system of  claim 25 , wherein at least one of the first spacer and the second spacer includes at least one channel running along a length of the first spacer or second spacer aligned with the longitudinal axis and exposing an inner portion of the first spacer or second spacer to facilitate tissue in-growth. 
     
     
         27 . The implant system of  claim 26 , wherein the second extension or third extension includes a body with a c-shaped aperture for receiving the first spacer or second spacer. 
     
     
         28 . The implant system of  claim 27 , wherein the c-shaped aperture includes a tab extending radially inward and engaging the at least one channel running along the length of the first spacer or the second spacer. 
     
     
         29 . The implant system of  claim 25 , wherein the second extension includes set screw adapted to engage a posterior side of the first spacer. 
     
     
         30 . The implant of  claim 25 , wherein the second lobe and fourth lobe are offset posteriorly relative to the fifth lobe and the seventh lobe to allow the first extension and second extension to interleave with the third extension and the fourth extension. 
     
     
         31 . The implant system of  claim 30 , wherein the second lobe and the fifth lobe engage a first side of the second spinous process and the fourth lobe and the seventh lobe engage a second side of the second spinous process. 
     
     
         32 . The implant system of  claim 25 , wherein the first extension includes at least one fastener adapted to engage at least one of the spinous processes to fix the first spacer to the spinous processes. 
     
     
         33 . The implant system of  claim 25 , wherein the second extension includes at least one fastener adapted to engage at least one of the spinous processes to fix the first spacer to the spinous processes. 
     
     
         34 . The implant system of  claim 25 , wherein the first extension and the second extension both include a plurality of fasteners, wherein a first portion of the plurality of fasteners on the first extension are adapted to be offset relative to a second portion of the plurality of fasteners on the second extension when the plurality of fasteners are engaged with the spinous processes. 
     
     
         35 . An implant for placement between spinous processes of adjacent vertebrae of a spine, the implant comprising:
 a hollow spacer with a medial end, a lateral end, and a longitudinal axis extending from the medial end to the lateral end, the spacer comprising opposing surfaces operable to abut the spinous processes and maintain minimum spacing between spinous processes;   a first extension integral with and projecting from the medial end of the spacer transverse to the longitudinal axis to lie generally alongside the spinous processes of adjacent vertebrae, the first extension including a first lobe extending superiorly long a first extension axis and a second lobe extending inferiorly long a second extension axis, wherein the first extension axis is offset anteriorly from an intersection with the longitudinal axis and the second extension axis is offset posteriorly from an intersection with the longitudinal axis; and   a second extension slidably engageable with the spacer opposing the first extension, the second extension including a third lobe extending superiorly long a third extension axis and a fourth lobe extending inferiorly long a fourth extension axis, wherein the third extension axis is offset anteriorly in line with the first extension axis and the fourth extension axis is offset posteriorly in line with the second extension axis.