Patent Publication Number: US-2012035727-A1

Title: Surgical implant device for the translation and fusion of a facet joint of the spine

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present patent application/patent is a continuation-in-part of U.S. patent application Ser. No. 12/875,374, filed on Sep. 3, 2010, and entitled “SURGICAL IMPLANT DEVICE FOR THE TRANSLATION AND FUSION OF A FACET JOINT OF THE SPINE,” which claims the benefit of priority of U.S. Provisional Patent Application No. 61/239,594, filed on Sep. 3, 2009, and entitled “SURGICAL IMPLANT DEVICE FOR THE TRANSLATION AND FUSION OF A FACET JOINT OF THE SPINE,” the contents of both of which are incorporated in full by reference herein. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to a novel surgical implant device for treating spinal stenosis, facet arthropathy, degenerative disc disease, and the like. More specifically, the present invention relates to a novel surgical implant device for the translation/distraction and subsequent stabilization/fusion of a facet joint of the spine in the treatment of such conditions. 
     BACKGROUND OF THE INVENTION 
     There are a variety of conventional surgical implant devices and methodologies for stabilizing/fusing a facet joint of the spine. Most of these devices and methodologies involve drilling between and across the articulating surfaces of the facet joint while un-translated/non-distracted and inserting a plug or other stabilization structure in the drilled hole(s). Some of these device and methodologies involve placing a bolt or other retention structure through (i.e. substantially perpendicularly across) or about the articulating surfaces of the facet joint while un-translated/non-distracted. These conventional surgical implant devices and methodologies, however, suffer from a number of significant shortcomings and often fail to adequately address patient symptoms. 
     BRIEF SUMMARY OF THE INVENTION 
     It is desirable, in many applications, to translate/distract the facet joint before stabilizing/fusing it, especially in the lumbar spine. This may be accomplished, for example, by placing a surgical implant device in the facet joint and rotating it, thus displacing the articulating surfaces of the facet joint with respect to one another with a translation motion and/or a distraction motion. Such a procedure may be carried out both left and right at each level of the spine. Further, all procedures of the present invention may be performed open, through a portal tube or the like, or percutaneously. 
     Advantageously, such displacement increases the size of the foramen, where the nerve roots exit the central spinal canal, thus addressing foraminal stenosis, which may cause leg symptoms. Such displacement also addresses central spinal canal stenosis by unbuckling or stretching out the redundant ligamentum flavum which connect each spinal segment posteriorly. Such displacement further unloads the posterior aspect of the intervertebral disc posteriorly, and may be used to address underlying degenerative disc disease, in addition to lumbar spinal stenosis, facet arthropathy (i.e. facet arthritis), and the like. 
     The surgical procedures of the present invention may be performed percutaneously or through two small incisions on the back, one on each side. An elongated device with a sharp point and a plurality of concentrically-arranged friction structures, for example, is inserted into the facet joint and rotated, thus providing translation/distraction. A retention sleeve is then slid down the elongated device and into or adjacent to and engaging the facet joint to maintain the facet joint in translation/distraction while the elongated device is removed. Subsequently or alternatively, a hole is drilled between and across the articulating surfaces of the facet joint through the retention sleeve and a plug or other novel surgical implant device is tamped into the hole to maintain the facet joint in translation/distraction. This later function may be accomplished using the retention sleeve itself, in the case that it is simply a toothed retention washer or the like. Alternatively, the novel surgical implant device may be inserted into the facet joint, rotated to translate/distract the facet joint, and then remain in place itself (optionally after additional seating) to hold the facet joint in the desired configuration. This surgical implant device may be a detachable end portion of the elongated device, for example. 
     Alternatively, after translating/distracting, a stellate/snowflake-shaped tamp may be impacted into and across the facet joint to create an outline for a serrated surgical implant device to subsequently be impacted into this outline. This provides an interference fit and prevents unwinding of the facet joint. Various surgical implant device configurations are contemplated, illustrated, and described herein, including various friction structures and various other structures that aide in the translation/distraction of the facet joint and variously fill the “gap” therein. 
     The goal of the present invention is to stabilize/fuse the facet joint in a desirable configuration that alleviates a given physical ailment or condition. The various surgical implant devices of the present invention may be made of machined allograft (i.e. bony) material, a surgically-implantable polymeric material, a surgically-implantable ceramic material, a surgically-implantable metallic material, etc., and may include one or more holes or pores for the impaction of another material that promotes the fusion of the superior and inferior facets of a facet joint. 
     In one exemplary embodiment, the present invention provides a surgical implant device for the translation/distraction and subsequent stabilization/fusion of a facet joint of a spine, including: a body that is selectively disposed at least partially between articulating surfaces of the facet joint; and one or more protruding structures disposed about the body, wherein, when the body is selectively rotated, the one or more protruding surfaces are configured to engage the articulating surfaces of the facet joint and move them with respect to one another. Optionally, the surgical implant device also includes a joint-spanning structure coupled to the body, wherein the joint-spanning structure is configured to substantially fill a space between the articulating surfaces of the facet joint and hold it in a moved configuration. 
     In another exemplary embodiment, the present invention provides a surgical implant method for the translation/distraction and subsequent stabilization/fusion of a facet joint of a spine, including: selectively disposing a body at least partially between articulating surfaces of the facet joint; and selectively rotating the body such that one or more protruding structures disposed about the body engage the articulating surfaces of the facet joint and move them with respect to one another. Optionally, the method also includes providing a joint-spanning structure coupled to the body, wherein the joint-spanning structure is configured to substantially fill a space between the articulating surfaces of the facet joint and hold it in a moved configuration. 
     In a further exemplary embodiment, the present invention provides a surgical implant system for the translation/distraction and subsequent stabilization/fusion of a facet joint of a spine, including: a tool that is selectively disposed at least partially between articulating surfaces of the facet joint; and one or more protruding structures disposed about the tool, wherein, when the tool is selectively rotated, the one or more protruding surfaces are configured to engage the articulating surfaces of the facet joint and move them with respect to one another. The surgical implant system also includes a sheath disposed about the tool, wherein the sheath is selectively slid down the tool to engage the facet joint to maintain the facet joint in a moved configuration while the tool is removed. The surgical implant system further includes a surgical implant device that is selectively disposed at least partially between articulating surfaces of the facet joint to maintain the facet joint in the moved configuration while the sheath is removed. 
     In a still further exemplary embodiment, the present invention provides a surgical implant method for the translation/distraction and subsequent stabilization/fusion of a facet joint of a spine, including: moving a first articulating surface of the facet joint with respect to a second articulating surface of the facet joint; forming a cut-away portion of each of the articulating surfaces of the facet joint; and disposing a surgical implant device in the cut-away portion of each of the articulating surfaces of the facet joint to prevent unwinding thereof. 
     In a still further exemplary embodiment, the present invention provides a surgical device for the translation/distraction and subsequent stabilization/fusion of a facet joint of a spine, including: a post that is selectively disposed partially between articulating surfaces of the facet joint; and a keel structure that is selectively disposed about the post and impacted into the articulating surfaces of the facet joint, wherein, when the keel structure is selectively rotated about the post, the articulating surfaces of the facet joint are moved with respect to one another. Optionally, the keel structure has a substantially planar configuration. Preferably, the keel structure has a sharpened lower portion. 
     In a still further exemplary embodiment, the present invention provides a surgical system for the translation/distraction and subsequent stabilization/fusion of a facet joint of a spine, including: a portal tube defining a first cut-away portion, wherein, when placed, the first cut-away portion provides surgical access to adjacent spinous processes of the spine. Optionally, the portal tube further defines a second cut-away portion disposed substantially opposite the first cut-away portion, wherein, when placed, the second cut-away portion provides surgical access to an associated facet joint of the spine. The surgical system also includes a distraction device that is selectively disposed within the tube, through the first cut-away portion, and between the adjacent spinous processes. The surgical system further includes a facet joint implant that is selectively disposed within the tube, through the second cut-away portion, and within a receiving hole formed in the facet joint. 
     In a still further exemplary embodiment, the present invention provides a surgical method for the translation/distraction and subsequent stabilization/fusion of a facet joint of a spine, including: through a portal tube, disposing a distraction device between adjacent spinous processes of the spine and distracting the adjacent spinous processes; forming a hole across the facet joint of the spine; and inserting a facet implant device in the hole formed across the facet joint. The surgical method also includes removing the distraction device and performing a discectomy. The surgical method further includes replacing the distraction device and again distracting the adjacent spinous processes. 
     In a still further exemplary embodiment, the present invention provides a surgical device for the translation/distraction and subsequent stabilization/fusion of a facet joint of a spine, including: a rotation device that is selectively disposed at least partially between and engages articulating surfaces of the facet joint, wherein the rotation device is operable for rotating and translating the articulating surfaces of the facet joint; and a translation sheath disposed about the rotation device that is selectively mated with a superior facet and an inferior facet of the facet joint, wherein the translation sheath is operable for rotating and further translating the articulating surfaces of the facet joint. The translation sheath comprises a plurality of raised structures disposed about a circumference thereof. The translation sheath comprises a plurality of spike structures disposed about a circumference thereof. 
     In a still further exemplary embodiment, the present invention provides a surgical implant device for the stabilization/fusion of a facet joint of a spine, including: a liquid or semi-solid polymeric material that is disposed in a cut-away portion of each articulating surface of the facet joint and subsequently allowed to harden to a solid to prevent movement thereof. Optionally, the surgical implant device also includes a solid material that is disposed within or about the liquid or semi-solid polymeric material within the cut-away portion of each articulating surface of the facet joint to prevent movement thereof. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is illustrated and described herein with reference to the various drawings, in which like reference numbers are used to denote like device components/method steps, as appropriate, and in which: 
         FIG. 1  is a schematic diagram illustrating one exemplary embodiment of the facet implant device of the present invention, and one exemplary embodiment of the facet translation/fusion method of the present invention; 
         FIG. 2  is a schematic diagram illustrating another exemplary embodiment of the facet implant device of the present invention, and another exemplary embodiment of the facet translation/fusion method of the present invention; 
         FIG. 3  is a schematic diagram illustrating one exemplary embodiment of the facet implant device of the present invention; 
         FIG. 4  is a schematic diagram illustrating another exemplary embodiment of the facet implant device of the present invention; 
         FIG. 5  is a schematic diagram illustrating a further exemplary embodiment of the facet implant device of the present invention; 
         FIG. 6  is a schematic diagram illustrating a still further exemplary embodiment of the facet implant device of the present invention; 
         FIG. 7  is a schematic diagram illustrating a still further exemplary embodiment of the facet implant device of the present invention; 
         FIG. 8  is a schematic diagram illustrating a still further exemplary embodiment of the facet implant device of the present invention; 
         FIG. 9  is a schematic diagram illustrating a still further exemplary embodiment of the facet implant device of the present invention; 
         FIG. 10  is a perspective diagram illustrating one exemplary embodiment of the facet implant device tool assembly of the present invention; 
         FIG. 11  is a series of schematic diagrams illustrating another exemplary embodiment of the facet translation/fusion method of the present invention; 
         FIG. 12  is a series of schematic diagrams illustrating a still further exemplary embodiment of the facet implant device of the present invention; 
         FIG. 13  is a schematic diagram illustrating one exemplary embodiment of the translation sheath of the present invention; 
         FIG. 14  is a schematic diagram illustrating one exemplary embodiment of the facet portal system of the present invention; 
         FIG. 15  is another schematic diagram illustrating one exemplary embodiment of the facet portal system of the present invention; 
         FIG. 16  is a further schematic diagram illustrating one exemplary embodiment of the facet portal system of the present invention; 
         FIG. 17  is a schematic diagram illustrating one exemplary embodiment of the facet keel device of the present invention; and 
         FIG. 18  is another schematic diagram illustrating one exemplary embodiment of the facet keel device of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIG. 1 , in one exemplary embodiment of the present invention, the facet implant device  10  is disposed between the superior facet  12  and the inferior facet  14  of the facet joint  16  of a spine. The facet implant device  10  includes one or more protruding structures  18  or friction surfaces that engage the articulating surfaces  13 ,  15  of the facet joint  16  when the facet implant device  10  is rotated in the facet joint  16 , the protruding structures  18  first contacting the articulating surfaces  13 ,  15 , then grabbing them, then translating/distracting them with respect to one another, and then holding them securely in this translated/distracted configuration. In the embodiment illustrated, the facet implant device  10  includes a substantially-cylindrical body  20  and two or four substantially-triangular or fin-like protruding structures  18  that have sharp surfaces or edges for engaging the articulating surfaces  13 ,  15 , although other suitable assemblies are contemplated herein. The facet implant device  10  has over all dimensions on the order of several millimeters, and may be made of machined allograft (i.e. bony) material, a surgically-implantable polymeric material, a surgically-implantable ceramic material, a surgically-implantable metallic material, etc. The facet implant device  10  may include one or more holes or pores  22  along its major axis and/or perpendicular to its major axis through the body  20  thereof for the impaction of another material that promotes the fusion of the superior and inferior facets  12 ,  14  of the facet joint  16 . In addition, the body  20  of the facet implant device  10  may have a threaded portion or other attachment means for receiving one or more tools by which it is tamped into the facet joint  16  and/or rotated. The implants and devices of the present invention may be placed in or between cut-away, roughened, otherwise prepared surfaces, or otherwise unprepared surfaces of the bony structures involved in all embodiments, provided that desirable and engagement therewith is achieved. In this respect, hole, bore, cut-away portion, roughened portion, prepared portion, receiving portion, and the like are all intended to be essentially synonymous and interchangeable. 
     Referring to  FIG. 2 , in another exemplary embodiment of the present invention, the facet implant device  30  is disposed between the superior facet  12  and the inferior facet  14  of the facet joint  16  of a spine. The facet implant device  30  includes one or more protruding structures  32  or friction surfaces that engage the articulating surfaces  13 ,  15  of the facet joint  16  when the facet implant device  30 , or a portion thereof, is rotated in the facet joint  16 , the protruding structures  32  first contacting the articulating surfaces  13 ,  15 , then grabbing them, then translating/distracting them with respect to one another, and then holding them securely in this translated/distracted configuration. In the embodiment illustrated, the facet implant device  30  includes a substantially-cylindrical body  34  and a plurality of substantially-triangular or tooth-like protruding structures  32  that have sharp surfaces or edges for engaging the articulating surfaces  13 ,  15 , although other suitable assemblies are contemplated herein. The facet implant device  30  has over all dimensions on the order of several millimeters, and may be made of machined allograft (i.e. bony) material, a surgically-implantable polymeric material, a surgically-implantable ceramic material, a surgically-implantable metallic material, etc. The facet implant device  30  may include one or more holes or pores  36  along its major axis and/or perpendicular to its major axis through the body  34  thereof for the impaction of another material that promotes the fusion of the superior and inferior facets  12 ,  14  of the facet joint  16 . In addition, the body  34  of the facet implant device  30  may have a threaded portion or other attachment means for receiving one or more tools by which it is tamped into the facet joint  16  and/or rotated. In the embodiment illustrated, the facet implant device  30  also includes a joint-spanning structure  38  coupled to the body  34 . This joint-spanning structure  38  may or may not rotate with the body  34  when it is rotated in the facet joint  16  and, in any case, is used to substantially fill the facet joint  16 , providing friction surfaces that prevent the articulating surfaces  13 ,  15  from sliding with respect to one another once translation/distraction has been achieved. Accordingly, the joint-spanning structure  38  may have a substantially-rectangular or other suitable shape and a thickness on the order of several millimeters. 
     Referring to  FIG. 3 , in one exemplary embodiment of the present invention, the facet implant device  10  includes one or more protruding structures  18  or friction surfaces that engage the articulating surfaces  13 ,  15  ( FIGS. 1 and 2 ) of the facet joint  16  ( FIGS. 1 and 2 ) when the facet implant device  10  is rotated in the facet joint  16 , the protruding structures  18  first contacting the articulating surfaces  13 ,  15 , then grabbing them, then translating/distracting them with respect to one another, and then holding them securely in this translated/distracted configuration. In the embodiment illustrated, the facet implant device  10  includes a substantially-cylindrical body  20  and two or four substantially-triangular or fin-like protruding structures  18  that have sharp surfaces or edges for engaging the articulating surfaces  13 ,  15 , although other suitable assemblies are contemplated herein. The facet implant device  10  has over all dimensions on the order of several millimeters, and may be made of machined allograft (i.e. bony) material, a surgically-implantable polymeric material, a surgically-implantable ceramic material, a surgically-implantable metallic material, etc. The facet implant device  10  may include one or more holes or pores  22  along its major axis and/or perpendicular to its major axis through the body  20  thereof for the impaction of another material that promotes the fusion of the superior and inferior facets  12 ,  14  ( FIGS. 1 and 2 ) of the facet joint  16 . In addition, the body  20  of the facet implant device  10  may have a threaded portion or other attachment means for receiving one or more tools by which it is tamped into the facet joint  16  and/or rotated. 
     Referring to  FIG. 4 , in another exemplary embodiment of the present invention, the facet implant device  30  includes one or more protruding structures  32  or friction surfaces that engage the articulating surfaces  13 ,  15  ( FIGS. 1 and 2 ) of the facet joint  16  ( FIGS. 1 and 2 ) when the facet implant device  30  is rotated in the facet joint  16 , the protruding structures  32  first contacting the articulating surfaces  13 ,  15 , then grabbing them, then translating/distracting them with respect to one another, and then holding them securely in this translated/distracted configuration. In the embodiment illustrated, the facet implant device  30  includes a substantially-cylindrical body  34  and a plurality of substantially-triangular or tooth-like protruding structures  32  that have sharp surfaces or edges for engaging the articulating surfaces  13 ,  15 , although other suitable assemblies are contemplated herein. The facet implant device  30  has over all dimensions on the order of several millimeters, and may be made of machined allograft (i.e. bony) material, a surgically-implantable polymeric material, a surgically-implantable ceramic material, a surgically-implantable metallic material, etc. The facet implant device  30  may include one or more holes or pores  36  along its major axis and/or perpendicular to its major axis through the body  34  thereof for the impaction of another material that promotes the fusion of the superior and inferior facets  12 ,  14  ( FIGS. 1 and 2 ) of the facet joint  16 . In addition, the body  34  of the facet implant device  30  may have a threaded portion or other attachment means for receiving one or more tools by which it is tamped into the facet joint  16  and/or rotated. 
     Referring to  FIG. 5 , in a further exemplary embodiment of the present invention, the facet implant device  40  includes one or more protruding structures  42  or friction surfaces that engage the articulating surfaces  13 ,  15  ( FIGS. 1 and 2 ) of the facet joint  16  ( FIGS. 1 and 2 ) when the facet implant device  40  is rotated in the facet joint  16 , the protruding structures  42  first contacting the articulating surfaces  13 ,  15 , then grabbing them, then translating/distracting them with respect to one another, and then holding them securely in this translated/distracted configuration. In the embodiment illustrated, the facet implant device  40  includes a substantially-cylindrical body  44  and two substantially-trapezoidal or fin-like protruding structures  42  that have sharp surfaces or edges for engaging the articulating surfaces  13 ,  15 , although other suitable assemblies are contemplated herein. The facet implant device  40  has over all dimensions on the order of several millimeters, and may be made of machined allograft (i.e. bony) material, a surgically-implantable polymeric material, a surgically-implantable ceramic material, a surgically-implantable metallic material, etc. The facet implant device  40  may include one or more holes or pores  46  along its major axis and/or perpendicular to its major axis through the body  44  thereof for the impaction of another material that promotes the fusion of the superior and inferior facets  12 ,  14  ( FIGS. 1 and 2 ) of the facet joint  16 . In addition, the body  44  of the facet implant device  40  may have a threaded portion or other attachment means for receiving one or more tools by which it is tamped into the facet joint  16  and/or rotated. 
     Referring to  FIG. 6 , in a still further exemplary embodiment of the present invention, the facet implant device  30  includes one or more protruding structures  32  or friction surfaces that engage the articulating surfaces  13 ,  15  ( FIGS. 1 and 2 ) of the facet joint  16  ( FIGS. 1 and 2 ) when the facet implant device  30 , or a portion thereof, is rotated in the facet joint  16 , the protruding structures  32  first contacting the articulating surfaces  13 ,  15 , then grabbing them, then translating/distracting them with respect to one another, and then holding them securely in this translated/distracted configuration. In the embodiment illustrated, the facet implant device  30  includes a substantially-cylindrical body  34  and a plurality of substantially-triangular or tooth-like protruding structures  32  that have sharp surfaces or edges for engaging the articulating surfaces  13 ,  15 , although other suitable assemblies are contemplated herein. The facet implant device  30  has over all dimensions on the order of several millimeters, and may be made of machined allograft (i.e. bony) material, a surgically-implantable polymeric material, a surgically-implantable ceramic material, a surgically-implantable metallic material, etc. The facet implant device  30  may include one or more holes or pores  36  along its major axis and/or perpendicular to its major axis through the body  34  thereof for the impaction of another material that promotes the fusion of the superior and inferior facets  12 ,  14  ( FIGS. 1 and 2 ) of the facet joint  16 . In addition, the body  34  of the facet implant device  30  may have a threaded portion or other attachment means for receiving one or more tools by which it is tamped into the facet joint  16  and/or rotated. In the embodiment illustrated, the facet implant device  30  also includes a joint-spanning structure  38  coupled to the body  34 . This joint-spanning structure  38  may or may not rotate with the body  34  when it is rotated in the facet joint  16  and, in any case, is used to substantially fill the facet joint  16 , providing friction surfaces that prevent the articulating surfaces  13 ,  15  from sliding with respect to one another once translation/distraction has been achieved. Accordingly, the joint-spanning structure  38  may have a substantially-rectangular or other suitable shape and a thickness on the order of several millimeters. In an alternative embodiment, neither the body  34  or the joint-spanning structure  38  may be rotated, but may simply be used to fill the facet joint  16  and any manufactured recesses and keep the facet joint  16  from unwinding. In this embodiment, only the upper and lower portions of the body  34  need have teeth or fins  32 , for example. 
     Referring to  FIG. 7 , in a still further exemplary embodiment of the present invention, the facet implant device  50  includes one or more protruding structures  52  or friction surfaces that engage the articulating surfaces  13 ,  15  ( FIGS. 1 and 2 ) of the facet joint  16  ( FIGS. 1 and 2 ) when the facet implant device  50  is rotated in the facet joint  16 , the protruding structures  52  first contacting the articulating surfaces  13 ,  15 , then grabbing them, then translating/distracting them with respect to one another, and then holding them securely in this translated/distracted configuration. In the embodiment illustrated, the facet implant device  50  includes a substantially-cylindrical body  54 , a substantially-conical insertion tip  56 , and two or four substantially-triangular or fin-like protruding structures  52  that have sharp surfaces or edges for engaging the articulating surfaces  13 ,  15 , although other suitable assemblies are contemplated herein. The facet implant device  50  has over all dimensions on the order of several millimeters, and may be made of machined allograft (i.e. bony) material, a surgically-implantable polymeric material, a surgically-implantable ceramic material, a surgically-implantable metallic material, etc. The facet implant device  50  may include one or more holes or pores  58  along its major axis and/or perpendicular to its major axis through the body  54  thereof for the impaction of another material that promotes the fusion of the superior and inferior facets  12 ,  14  ( FIGS. 1 and 2 ) of the facet joint  16 . In addition, the body  54  of the facet implant device  50  may have a threaded portion  59  or other attachment means for receiving one or more tools by which it is tamped into the facet joint  16  and/or rotated. Optionally, one of the tools may act as a plunger through which fusion-promoting material is introduced into the facet implant device  50 . 
     Referring to  FIG. 8 , in a still further exemplary embodiment of the present invention, the facet implant device  60  includes one or more protruding structures  62  or friction surfaces disposed concentrically there about (such as threads or the like) that engage the articulating surfaces  13 ,  15  ( FIGS. 1 and 2 ) of the facet joint  16  ( FIGS. 1 and 2 ) when the facet implant device  60  is rotated in the facet joint  16 , the protruding structures  62  first contacting the articulating surfaces  13 ,  15 , then grabbing them, then translating/distracting them with respect to one another, and then holding them securely in this translated/distracted configuration. In the embodiment illustrated, the facet implant device  60  includes a substantially-conical body  64  and a plurality of protruding structures  62  that have sharp surfaces or edges for engaging the articulating surfaces  13 ,  15 , although other suitable assemblies are contemplated herein. The facet implant device  60  has over all dimensions on the order of several millimeters, and may be made of machined allograft (i.e. bony) material, a surgically-implantable polymeric material, a surgically-implantable ceramic material, a surgically-implantable metallic material, etc. The facet implant device  60  may include one or more holes or pores  66  along its major axis and/or perpendicular to its major axis through the body  64  thereof for the impaction of another material that promotes the fusion of the superior and inferior facets  12 ,  14  ( FIGS. 1 and 2 ) of the facet joint  16 . In addition, the body  64  of the facet implant device  60  may have a threaded portion or other attachment means for receiving one or more tools by which it is tamped into the facet joint  16  and/or rotated. 
     Referring to  FIG. 9 , in a still further exemplary embodiment of the present invention, the facet implant device  70  includes one or more protruding structures  72  or friction surfaces disposed axially there about (such as ridges or the like) that engage the articulating surfaces  13 ,  15  ( FIGS. 1 and 2 ) of the facet joint  16  ( FIGS. 1 and 2 ) when the facet implant device  70  is rotated in the facet joint  16 , the protruding structures  72  first contacting the articulating surfaces  13 ,  15 , then grabbing them, then translating/distracting them with respect to one another, and then holding them securely in this translated/distracted configuration. In the embodiment illustrated, the facet implant device  70  includes a substantially-conical body  74  and a plurality of protruding structures  72  that have sharp surfaces or edges for engaging the articulating surfaces  13 ,  15 , although other suitable assemblies are contemplated herein. The facet implant device  70  has over all dimensions on the order of several millimeters, and may be made of machined allograft (i.e. bony) material, a surgically-implantable polymeric material, a surgically-implantable ceramic material, a surgically-implantable metallic material, etc. The facet implant device  70  may include one or more holes or pores  76  along its major axis and/or perpendicular to its major axis through the body  74  thereof for the impaction of another material that promotes the fusion of the superior and inferior facets  12 ,  14  ( FIGS. 1 and 2 ) of the facet joint  16 . In addition, the body  74  of the facet implant device  70  may have a threaded portion or other attachment means for receiving one or more tools by which it is tamped into the facet joint  16  and/or rotated. 
     It should be noted that, in all of the above embodiments, the articulating surfaces  13 ,  15  ( FIGS. 1 and 2 ) of the facet joint  16  ( FIGS. 1 and 2 ) may be cut, chiseled, gouged, or otherwise formed to substantially conform to the various surfaces of the various facet implant devices. The facet implant devices may also be advanced into the facet joint  16  upon rotation, or may be inserted, rotated to perform translation/distraction, and then further inserted to lock the facet joint  16 . Any combination of elements/steps is possible. 
       FIG. 10  is a perspective diagram illustrating one exemplary embodiment of the facet implant device tool assembly  80  of the present invention. An elongated device  82  with a sharp point  84  and a plurality of concentrically-arranged friction structures  86 , for example, is inserted into the facet joint  16  ( FIGS. 1 and 2 ) and rotated, thus providing translation/distraction. A retention sleeve  88  is then slid down the elongated device and into or adjacent to and engaging the facet joint  16  to maintain the facet joint  16  in translation/distraction while the elongated device  82  is removed. Subsequently or alternatively, a hole is drilled between and across the articulating surfaces  13 ,  15  ( FIGS. 1 and 2 ) of the facet joint  16  through the retention sleeve  88  and a plug or other novel surgical implant device is tamped into the hole to maintain the facet joint  16  in translation/distraction. This later function may be accomplished using the retention sleeve  88  itself, in the case that it is simply a toothed retention washer or the like. Alternatively, the novel surgical implant device may be inserted into the facet joint  16 , rotated to translate/distract the facet joint, and then remain in place itself (optionally after additional seating) to hold the facet joint  16  in the desired configuration. This surgical implant device may be a detachable end portion of the elongated device  82 , for example. Alternatively, after translating/distracting, a stellate/snowflake-shaped (or other patterned) tamp may be impacted into and across the facet joint  16  to create an outline for a serrated surgical implant device to subsequently be impacted into this outline. This provides an interference fit and prevents unwinding of the facet joint  16 . This facet translation/fusion method is illustrated in  FIG. 11 . 
     Referring to  FIG. 12 , in a still further exemplary embodiment of the present invention, the facet implant device  100  is disposed between the superior facet  12  and the inferior facet  14  of the facet joint  16  of a spine, optionally after prior translation/distraction of the facet joint  16 . The facet implant device  100  includes a polymeric material  104  or the like (i.e. not necessarily a polymer) that is injected into the drilled or formed hole or otherwise prepared or unprepared space as a liquid or semi-solid and then rapidly hardens into a solid, thereby securely holding the facet joint  16  in its present configuration. Optionally, the polymeric material  104  or the like is disposed about and/or through a solid implant  102  or other solid device that is inserted into the drilled or formed hole or otherwise prepared or unprepared space previously or subsequently. Again, the facet implant device  100  has over all dimensions on the order of several millimeters, and the solid portion (if used) may be made of machined allograft (i.e. bony) material, a surgically-implantable polymeric material, a surgically-implantable ceramic material, a surgically-implantable metallic material, etc. The solid portion of the facet implant device  100  (if used) may include one or more holes or pores along its major axis and/or perpendicular to its major axis through the body thereof for the impaction of another material that promotes the fusion of the superior and inferior facets  12 ,  14  of the facet joint  16 . In addition, the body of the solid portion of the facet implant device  100  (if used) may have a threaded portion or other attachment means for receiving one or more tools by which it is tamped into the facet joint  16  and/or rotated. 
     Referring to  FIG. 13 , in a still further exemplary embodiment of the present invention, a translation sheath  110  is provided that aides in the translation of the superior and inferior facets  12  and  14  of a facet joint  16 , as is described in other related embodiments of the present invention. For example, this translation sheath  110  may be used in conjunction with the facet implant device tool assembly  80  of  FIG. 10 . The translation sheath  110  includes a plurality of raised teeth, serrations, or other friction structures  112  disposed around its circumference. Two or more of these raised teeth, serrations, or other friction structures  112  include spike structures  114 , optionally disposed about 180 degrees from each other about the circumference of the translation sheath  110 . These spike structures  114  are configured to securely engage the superior and inferior facets  12  and  14 , such that the translation sheath  110  may be manually rotated, thereby translating the superior and inferior facets  12  and  14 . A rotation device  116  is selectively extended from within the translation sheath  110 , and is also operable for achieving purchase with and rotating the facet joint  16 , as is also described in other related embodiments of the present invention. This extension may occur before and/or after the translation sheath  110  is advanced onto the facet joint  16 . Optionally, the rotation device  116  is used to translate the facet joint  16 , and then the translation sheath  110  is tapped into place and used to further translate the facet joint  16 . Thus, these rotations may be complementary. It will be understood by those of ordinary skill in the art that the translation sheath  110 , or a similar facet joint engagement and translation device, may also be used alone, without a device such as the rotation device  116  or other device, to engage and translate or distract the facet joint  16 . Likewise, it will be understood by those of ordinary skill in the art that the rotation device  116 , or a similar facet joint engagement and translation device, or importantly a facet joint implant itself, may also be used alone, without a device such as the translation sheath  110  or other device, to engage and translate or distract and hold the facet joint  16 . In this sense, parts of all of the embodiments of the present invention may be used selectively with parts of other embodiments. 
     Referring to  FIGS. 14-16 , in a still further exemplary embodiment of the present invention, a facet portal system  120  is provided that provides surgical access to adjacent spinous processes  17  and  19  such that they may be distracted, as well as the associated facet joint  16  such that it may be translated and or fused as taught through this disclosure. This essentially allows the associated disc to be unloaded and a partial or total posterior discectomy to be performed in conjunction with a facet fusion. The facet portal system  120  is selectively disposed in the triangular region between the adjacent spinous processes  17  and  19  and the associated facet joint  16 . An arch-shaped cut-away  122  or the like disposed on one side of the lower portion of the facet portal system  120  provides surgical access to the adjacent spinous processes  17  and  19 , while, optionally, an arch-shaped cut-away  124  or the like disposed on the other side of the lower portion of the facet portal system  120  provides surgical access to the associated facet joint  16  (such access may, however, be available without the use of the arch-shaped cut-away  124  or the like, either through the bottom or outside of the facet portal system  12 , for example). Once the facet portal system  120  is in place, a distractor  130  is placed through the facet portal system  120  and into the interspinous process space, and the adjacent spinous processes  17  and  19  are distracted. This unloads the disc and translates the facet joint  16 . At this point, the facet joint  16  is drilled or otherwise prepared as described throughout this disclosure and the distractor  130  is removed. Next, a partial posterior discectomy is performed and the distractor  130  is replaced and distraction is restored, again unloading the disc and translating the facet joint  16 . At this point, a facet implant is placed to fuse the facet joint  16  as described throughout this disclosure, also maintaining the spinous process distraction. Finally, the distractor  130  and facet portal system  120  are removed. It will be understood by those of ordinary skill in the art that the ordering of these steps may be varied. For example, a partial or total discectomy may be performed at any point, and may be omitted. 
     Referring to  FIGS. 17 and 18 , in a still further exemplary embodiment of the present invention, a rigid or semi-rigid needle or post  150  is selectively disposed between the superior facet  12  and the inferior facet  14  of the facet joint  16  of a spine and acts to localize the facet joint  16 . Am appropriately rigid wire  150  could also be used for this purpose equally. Subsequently, a rigid or semi-rigid cannulated keel structure  152  having a substantially-planar or other suitable configuration and a sharpened lower edge is guided over the needle or post  150  into engagement with the superior facet  12  and the inferior facet  14 , and impacted into or otherwise engaged with the two halves of the facet joint  16 , optionally at an offset angle relative to the two halves of the facet joint  16 . Accordingly, it will be readily apparent to those of ordinary skill in the art that the keel structure  152  may have a variety of shapes, sizes, and configurations suitable for securely engaging the facet joint  16 . Once in place, the keel structure  152  is rotated, thereby translating the facet joint  16 , which is optionally also held in this translated state by any of the means provided in the present disclosure. It will be understood by those of ordinary skill in the art that the keel structure  152  or other similar device does not have to be cannulated, and may be used without the needle, post, or wire  150  equally. Further, the keel structure  150  may only engage a facet  12  or  14  on one side of the facet joint  16 , thereby moving that facet  12  or  14  with respect to the other facet  12  or  14 , which is left essentially unmoved. In this sense, the keel structure  152  could be a one-sided structure. Still further, the keel structure  152  may not be impacted into the facet(s)  12  and/or  14 , but may simply engage a roughened or otherwise prepared surface of one or both. This equivalence, between cut-away, roughened, and otherwise prepared surfaces of the bony structures involved applies equally throughout all embodiments of the present invention—all of these terms being defined as such surfaces being prepared for accepting engagement with the various devices and implants. 
     Although the present invention is illustrated and described herein with reference to preferred embodiments and specific examples thereof, it will be readily apparent to those of ordinary skill in the art that other embodiments and examples may perform similar functions and/or achieve like results. All such equivalent embodiments and examples are within the spirit and scope of the present invention, are contemplated thereby, and are intended to be covered by the following claims.