US20190254720A1 - Laminoplasty implants devices - Google Patents

Abstract

Laminoplasty plates are engageable to at least one portion of a divided lamina to maintain a desired spacing relative to the spinal canal. The laminoplasty plates include a spacer portion having a first end and a second end that spans a gap formed by at least one of a divided lamina portion. The laminoplasty plates can include a lamina engagement portion at one end for engagement with the divided lamina portion.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS:
• This application is a divisional of U.S. patent application Ser. No. 10/447,126 filed on May 28, 2003, which claims the benefit of the filing date of the Provisional Application Ser. No. 60/384,573 filed May 30, 2002. Each of the referenced applications is incorporated herein by reference in its entirety.
BACKGROUND
• The present invention relates to the field of laminoplasty, and, more particularly, to laminoplasty devices and methods.
• Every year there are a significant number of people who suffer severe neck, back, and/or spine injuries from trauma (seeFIG. 1 for a perspective view of a typicalhuman spine100, including the cervical110, thoracic120,lumbar130,sacrum140, andcoccyx150 regions). These injuries include cervical fractures, fracture dislocations combined with retropulsion of the disc, and other major injuries. Also, each year many people undergo spine surgery for degenerative diseases, especially degenerative spinal stenosis. In spinal stenosis, the spinal canal, which contains and protects the spinal cord and nerve roots, narrows, which results in compression of the spinal cord and nerves. Surgical goals can include a decompression of all compressed levels of the spine and stabilization with solid fusion.
• To provide further anatomical background,FIG. 2 is a perspective view, showing the structure of atypical vertebra200. The exact structure of the vertebrae in each section of the spine may vary somewhat to accommodate the function required of that section. Nevertheless, thetypical vertebra200 includes an anterior portion called thespinal body210 and a posterior portion called thevertebral arch220 which surround thespinal canal280. Thevertebral arch220 includes thespinous process250, which is connected to thearticular facet230 and thetransverse facet260 bylaminae240. Thefacets230,260 are connected to thespinal body210 bypedicles270.
• There are two posterior surgical methods for creating more room in the spinal canal. The first is a laminectomy in which the bony structures forming the back of the canal and the associated ligaments are removed. In the cervical region, a laminectomy can lead to spinal instability, or what is referred to as the “swan neck” deformity. This deformity can be a very difficult problem to correct and can cause substantial discomfort in the neck and shoulders due to the lack of the supporting structures at the back of the vertebrae which normally perform some of the work of keeping the neck in the right shape. It can also lead to further spinal cord damage.
• An alternative way of relieving spinal cord pressure is a surgical procedure called a laminoplasty. Laminoplasty procedures concern altering one or more of the bony vertebral structures that surround and define the spinal canal. For example, the bony structures can been weakened and flexed or swung posteriorly to open the canal and provide additional room for the spinal cord. A problem associated with this procedure concerns stabilizing the altered one or more vertebrae for proper healing.
• The laminoplasty technique is often referred to as an “open door laminoplasty,” because the back of one or more vertebrae is made to swing open like a door. There are multiple variations of the laminoplasty procedure, including the hemilateral open door laminoplasty (a.k.a., single door laminoplasty), and the bilateral open door laminoplasty (a.k.a., middorsal laminoplasty, French door laminoplasty, or double door laminoplasty).
• For the hemilateral open door laminoplasty, one challenge is to securely maintain the separation between the posterior portion and the anterior portion of the divided lamina. Although it is known to use a bone graft to provide this separation, the use of such grafts can require additional surgery and time to harvest an appropriate piece of graft bone, typically from the pelvis of the patient or cadaver. Moreover, it is possible for the bone graft to move after the laminoplasty surgery. This potentially causes a narrowing of the cross-sectional area of the spinal canal, impingement on the patient's spinal cord, and/or disruption or prolongation of fusion.
• With regard to the French door laminoplasty, the challenges can be even greater. For example, sutures have been used to secure a bone graft to the sectioned and separated laminae. Such sutures, however, are technically difficult, time consuming to insert, and typically do not firmly secure the bone graft to the sectioned laminae. Thus, subsequent movement between the bone graft and either of the two sectioned laminae can disadvantageously disrupt and/or prolong fusion therebetween.
SUMMARY
• A laminoplasty plate is provided for use with a spinal canal having an increased cross-sectional area. The plate includes a spacer portion that spans a gap formed by displacement of divided lamina portions. The plate includes a first lamina engagement portion adjacent a first end of the bone spacer portion that includes a first plurality of flanges. The first flanges are positionable in contact with or adjacent to an outer surface of the first divided spinal lamina at one or more locations about the lamina.
• A laminoplasty plate is provided to stabilize a surgically divided spinal lamina associated with a laminoplasty. The plate includes a spacer portion and a lamina engagement portion. The lamina engagement portion can include a cup, a cuff, and/or a plurality of flanges for receiving or extending about a portion of the divided lamina.
• A laminoplasty plate is provided for stabilizing at least one surgically divided spinal lamina associated with a laminoplasty. The plate includes a spacer portion spanning a gap formed by a removal of a spinal process and a separated pair of laminae. The plate also includes a first lamina engagement portion adjacent a first end of the spacer portion, the first lamina engagement portion including a first bone-grasping portion. The plate further includes a second lamina engagement portion adjacent a second end of the spacer portion, the second lamina engagement portion including a second bone-grasping portion.
• A laminoplasty plate is provided for securing a surgically divided spinal lamina associated with a laminoplasty. The plate includes a spacer portion for spanning a gap formed by removal of at least a portion of a lamina during the laminoplasty. The plate also includes a first engaging portion adjacent a first end of the spacer portion. The first engaging portion extends along at least first and second sides of the divided spinal lamina.
• There is provided a plate for a laminoplasty procedure that includes increasing a cross-sectional area of a spinal canal. The plate comprises a spacer portion having a first end and a second end. The spacer portion is positionable between first and second portions of a divided spinal lamina. The plate includes a first lamina engagement portion adjacent the first end of the spacer portion. The first lamina engagement portion includes a first plurality of lamina stabilizing flanges extendable along at least two of the anterior, posterior, superior and inferior surfaces of the first portion of the divided lamina.
• There is provided a plate for a laminoplasty procedure that increases a cross-sectional area of a spinal canal. The plate comprises a spacer portion having a first end and a second end. The spacer portion is positionable between first and second portions of a divided spinal lamina. The plate includes a first lamina engagement portion adjacent the first end of the spacer portion. The first lamina engagement portion includes a first plurality of flanges positionable along at least two of the anterior, posterior, superior and inferior surfaces of the first portion of the divided lamina. A second lamina engagement portion can be provided adjacent the second end of the spacer portion. The second lamina engagement portion can include one or more flanges positionable along at one of the anterior, posterior, superior and inferior surfaces of the second portion of the divided lamina.
• There is provided a plate for stabilizing a surgically divided spinal lamina associated with a laminoplasty that includes a spacer portion positionable between the spinal lamina and at least one lamina engagement portion. The lamina engagement portion includes at least one flange having a bone engagement mechanism extending therefrom for engaging the adjacent portion of the divided lamina.
• There is provided a laminoplasty plate for stabilizing a surgically divided spinal lamina associated with a laminoplasty. The plate comprises a spacer portion and a plurality of flanges extending therefrom for restraining movement between the spacer portion and the surgically divided spinal lamina in at least two directions.
• There is provided a plate for a laminoplasty procedure that increases a cross-sectional area of a spinal canal. The plate comprises a spacer portion positionable in a gap formed by displacement of a first divided spinal lamina portion. A first lamina engagement portion extending from an end of the spacer portion is adapted to contact the first divided spinal lamina portion at a plurality of locations about its perimeter.
• There is provided a laminoplasty plate for securing a surgically divided spinal lamina associated with a laminoplasty. The plate comprises a spacer portion having a first end and a second end. The spacer portion is positionable in or adjacent a gap formed by removal of at least a portion of a lamina during the laminoplasty. The plate includes a first lamina engagement portion extending from the first end of the spacer portion. The lamina engagement portion includes one of a lamina engaging cup or cuff adapted to extend substantially about a first portion of the divided spinal lamina.
• There is provided a laminoplasty plate for stabilizing a surgically divided spinal lamina associated with a laminoplasty that includes a spacer portion and a lamina engaging cup adjacent an end of the spacer portion.
• There is provided a laminoplasty plate for stabilizing a surgically divided spinal lamina associated with a laminoplasty that includes a spacer portion and a lamina engaging cuff adjacent an end of the spacer portion.
• There is provided a laminoplasty plate for stabilizing a surgically divided lamina associated with a laminoplasty. The plate includes a spacer portion having opposed first and second ends. The spacer portion is positionable in or adjacent a gap formed by a removal of a spinal process and/or separated portions of one or more lamina. Adjacent one end of the spacer portion is a first lamina engagement portion that includes a first bone-grasping portion. A second lamina engagement portion is adjacent the other end of the spacer portion and includes a second bone grasping portion.
• A method for stabilizing at least one surgically divided spinal lamina associated with a laminoplasty is provided. The method includes providing a laminoplasty plate having a spacer portion that includes a first end and a second end, the laminoplasty plate also having a first lamina engagement portion adjacent the first end, the first lamina engagement portion including a first plurality of bone grasping portions. The method also includes retaining a predetermined gap between a first divided lamina portion and a second divided lamina portion with the spacer portion of the laminoplasty plate.
• There is provided a method for stabilizing a surgically divided spinal lamina associated with a hemilateral open door laminoplasty. The method includes providing to a surgical patient a laminoplasty plate having a spacer portion that includes a first end and a second end, the laminoplasty plate also having a first engagement portion adjacent the first end of the spacer portion. The method further includes contacting the first engagement portion to an anterior surface and a posterior surface of a first portion of a divided spinal lamina.
• There is provided a method for stabilizing surgically divided spinal laminae associated with a French door laminoplasty that includes providing to a surgical patient a laminoplasty plate having a spacer portion that includes opposed first and second ends. The laminoplasty plate also has a first lamina engagement portion adjacent the first end of the spacer portion and a second lamina engagement portion adjacent the second end of the spacer portion. The plate is positioned adjacent the divided spinal laminae so that the plate extends between a first divided lamina and a second divided lamina and across a gap formed by a removal of a spinal process associated with the vertebra.
BRIEF DESCRIPTION OF THE DRAWINGS
• The invention and its wide variety of potential embodiments will be more readily understood through the following detailed description, with reference to the accompanying drawings in which:
• FIG. 1 is a perspective view of a typical human spine.
• FIG. 2 is a perspective view of a typical vertebra.
• FIG. 3 is an exploded perspective view of the typical vertebra ofFIG. 2.
• FIG. 4 is a plan view of a first stage of a hemilateral open door laminoplasty.
• FIG. 5 is a plan view of a second stage of a hemilateral open door laminoplasty.
• FIG. 6 is a plan view of a third stage of a hemilateral open door laminoplasty showing a bone graft inserted between the divided lamina portions.
• FIG. 7 is a plan view in partial section of a fourth stage of a hemilateral open door laminoplasty and one embodiment of a laminoplasty plate of the present invention.
• FIG. 8 is a perspective view of another embodiment laminoplasty plate.
• FIG. 9 is an elevation view of the laminoplasty plate ofFIG. 8.
• FIG. 10 is a right side view of the laminoplasty plate ofFIG. 8.
• FIG. 11 is a perspective view another embodiment laminoplasty plate
• FIG. 12 is an elevation view of the laminoplasty plate ofFIG. 11.
• FIG. 13 is a right side view of the laminoplasty plate ofFIG. 11.
• FIG. 14 is a perspective view of a further embodiment laminoplasty plate.
• FIG. 15 is a perspective view of another embodiment laminoplasty plate.
• FIG. 16 is an elevation view of yet another embodiment laminoplasty plate.
• FIG. 17 is a section view along line17-17 ofFIG. 16.
• FIG. 18 is an elevation view of another embodiment laminoplasty plate.
• FIG. 19 is a section view along line19-19 ofFIG. 18.
• FIG. 20 is a plan view of a vertebra having a French door laminoplasty and another embodiment of a laminoplasty plate secured to the vertebra.
• FIG. 21 is a perspective view of another embodiment laminoplasty plate.
• FIG. 22 is a plan view in partial section of a vertebra having a French door laminoplasty and another embodiment of a laminoplasty plate secured to the vertebra.
• FIG. 23 is a perspective view of another embodiment laminoplasty plate.
• FIG. 24 is an elevation view of another embodiment laminoplasty plate.
• FIG. 25 is a section view along line25-25 ofFIG. 24.
• FIG. 26 is an elevation view of another embodiment laminoplasty plate.
• FIG. 27 is a section view along line27-27 ofFIG. 26.
• FIG. 28 is a perspective view of another embodiment laminoplasty plate as viewed from the posterior side.
• FIG. 29 is a perspective view of the anterior side of the laminoplasty plate ofFIG. 28.
• FIG. 30 is a perspective view of a spacer member.
DETAILED DESCRIPTION
• For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Any such alterations and further modifications in the illustrated devices, and any such further applications of the principles of the invention as illustrated therein are contemplated as would normally occur to one skilled in the art to which the invention relates.
• A system for stabilizing first and second divided lamina portions as a result of a laminoplasty procedure is provided. The divided lamina portions can be created as the result of hemilateral open door laminoplasty or French door laminoplasty procedures. Certain embodiments may be more particularly suited for a certain laminoplasty procedure, however, aspects of each embodiment have application in any laminoplasty procedure.
• FIGS. 4-7 are plan views showing a procedure for a hemilateral open door laminoplasty onvertebra400 for securement of alaminoplasty system700. In the initial stage of the procedure the patient is positioned appropriately, and an incision is made to expose the posterior elements of the vertebrae of interest. Typically, any osteophytes are removed, and the spinous process can be removed. Arelief415 is cut down the medial cortical layer oflamina460 of at least onevertebra400.Relief415 can be in the form of a groove, gutter, or trough, and formed using a high-speed burr drill. In one specific embodiment,relief415 has a depth of approximately 3 to 4 millimeters and a width of approximately 3 millimeters to divide the lamina on what will be the “open” side. Then, a similar method can be used to thin the bone oflamina460 on the opposite side to create abone hinge450. In addition, the associated ligamentum flavum, capsule, and/or veins can be divided to allow outward rotation of the divided lamina.
• InFIG. 5 theposterior portion420 of the dividedlamina410 is rotated outwardly or posteriorly about the hingedlamina460, thereby opening and enlarging the cross-sectional area of thespinal canal440. InFIG. 6,spacer member730 is inserted between theposterior portion420 of the divided lamina and the anterior portion (lateral mass)430 of the divided lamina.Spacer member730 can preventposterior portion420 of the divided lamina from closing from the new position toward the original position. The divided lamina can tightly abutspacer member730, which can act as a wedge to prevent further movement of the divided lamina toward one another.
• The spacer members discussed herein can be a non-fusion member that supports the divided lamina, or a fusion member that also provides an avenue or platform for fusion of the divided lamina. For example, the spacer members can be a bone graft or an artificial device providing one or more avenues for bone growth between the divided lamina. The spacer members can be constructed of any biocompatible material, including metals and metal alloys, ceramics, plastics, resorbable materials, non-resorbable materials, bone material and/or composites. The spacer members can be a bone graft made from actual or synthetic bone and/or DBM (demineralized bone matrix). The spacer members can include a bone growth facilitating or inducing material, such as a bone chips, paste or putty and/or carriers such as a sponge, matrix, and/or sheet impregnated with a protein such as BMP (bone morphogenic protein), LMP (LIM Mineralization Protein), etc.
• FIG. 7 includeslaminoplasty system700 for stabilizing first and second divided lamina portions separated to enlarge the spinal canal.System700 includes alaminoplasty plate710 secured to one or more vertebra upon which a hemilateral open door laminoplasty has been performed.Laminoplasty plate710 can be attached to theposterior portion420 of the divided lamina, optionally to aspacer member730, and to the anterior portion (lateral mass)430 of the divided lamina (and/or to the articular facet) to secure thespacer member730 in place.Laminoplasty plate710 resists the door or opening between the divided lamina from opening or closing, and also maintains the positioning ofspacer member730.
• Laminoplasty plate710 can include aspacer portion715 and a lamina engaging portion at one end thereof including a first plurality offlanges750,760. The lamina engaging portion is engageable with theadjacent posterior portion420 of the lamina to assist in reducing, restraining, and/or preventing the movement of theposterior portion420 relative to plate710 and/or with respect to thespacer member730. This can promote healing by, for example, facilitating fusion between the end of theposterior portion420 and the end of thespacer member730.
• The opposite end ofcentral spacer portion715 includes a second lamina engaging portion. In the illustrated embodiment, the second lamina engaging portion includes one ormore flanges745 that assist in reducing, restraining, and/or preventing the movement of theanterior portion430 of the divided lamina and/or lateral mass relative to plate710 and/or with respect tospacer member730. This can promote healing by, for example, facilitating fusion between the divided end of theanterior portion430 and the end ofspacer member730.Spacer portion715 can have sufficient structural strength to shield the spine and/or spinal canal in a manner approximately equivalent to, and/or better than, the pre-surgery bone structure.
• One ormore securement mechanisms770, such as a screw with or without a locking mechanism, can be inserted throughlaminoplasty plate710 via one or more securement openings through theplate710 and into dividedlamina portions420,430, and/orspacer member730.Spacer member730 may further include one or more drilled and/or threadedbores732 for receiving and engaging one ormore securement mechanisms770 inserted throughlaminoplasty plate710, thereby securinglaminoplasty plate710 tospacer member730. Securement mechanisms other than bone screws are also contemplated, such as fasteners, anchors, nails, staples, nuts and bolts, glue, bone cement, and/or pins.
• FIGS. 8, 9 and 10 show anotherembodiment laminoplasty plate800 that can be employed, for example, with a hemilateral open door laminoplasty system, although application with other laminoplasty procedures is contemplated.Plate800 includes aspacer portion810 sized to span the divided portions of the lamina when in their appropriate respective open door positions. One end ofspacer portion810 includes a firstlamina engaging portion815 that includes a first plurality offlanges820 that can be attached to or engage adjacent, opposing, and/or distributed locations about exterior surfaces of, for example, the posterior portion of the divided lamina.
• The other end ofspacer portion810 includes alamina engaging portion825 that includes a second plurality offlanges830,835 that can be attached to or engage adjacent, opposing, and/or distributed locations on an exterior surface of, for example, an anterior portion of the divided lamina and/or the corresponding facet.Flange830 can extend along the posterior surface of the anterior portion of the divided lamina.Flanges835 can each be a ledge that abuts and/or engages the divided surface of the anterior portion of the divided lamina, i.e. the surface oriented toward the other divided lamina portion.Flanges835 are positioned adjacent respective ones of the superior and inferior edges ofspacer portion810, andflange830 extends from and has generally the same width asspacer portion810. The space betweenflanges835 provides a pathway for engagement of the spacer member with a bony surface of the divided lamina portion.Flanges835 can be transverse toflange830. In one embodiment,flanges835 are orthogonal to flange830. Other embodiments contemplate other orientations betweenflanges835 andflange830.
• Securement openings840 can receive a securement mechanism such as, for example, a screw to be inserted into the underlying bone and/or fusion member (not shown) and secure the laminoplasty plate to the bone and/or fusion member. The securement mechanisms can include a locking mechanism, such as tabs or a secondary screw, to prevent backing out from theopenings840.Spacer portion810 can be provided with awidth895 extending in the direction of the central spinal column axis whenplate800 is secured to the divided lamina. In one specific embodiment,width895 can be sized for a single vertebral level, and can range from about 5 millimeters to about 20 millimeters. Other embodiments contemplate other values for width of the spacer portions discussed herein. For example, the widths can be sized to span two or more vertebral levels.
• Flange820 forms anangle891 withspacer portion810, andflange830 along the posterior face of the divided lamina portion forms anangle892 withspacer portion810.Angles891 and892 can be the same, as shown, or be of different values. In one specific embodiment, angles891 and892 can be about 45 degrees. Other embodiments contemplateangles891 and892 ranging from 35 to 55 degrees, ranging from 25 to 65 degrees, or ranging from 0 degrees to 90 degrees.
• FIGS. 11, 12 and 13 show anotherembodiment laminoplasty plate900 that can be that can be employed, for example, with a hemilateral open door laminoplasty system, although application with other laminoplasty procedures is contemplated. Except as noted,laminoplasty plate900 can be similar tolaminoplasty plate800 ofFIGS. 8, 9 and 10. One end of aspacer portion910 includes a firstlamina engaging portion915 that includes a first plurality offlanges920 that can be attached to or engage adjacent, opposing, and/or distributed locations about exterior surfaces of, for example, the posterior portion of the divided lamina.
• Plate900 includes a secondlamina engaging portion925 at the other end ofspacer portion910 that includesflange930 and a pair offlange ledges935.Flange ledges935 are positioned adjacent to one of the edges ofspacer portion910, andflange930 extends fromspacer portion910 betweenflanges935.Flanges935 can be transverse toflange930. In one embodiment,flanges935 are orthogonal to flange930. Other embodiments contemplate other orientations betweenflanges935 andflange930.Securement openings940 can allow one or more securement mechanisms (not shown) such as, for example a bone screw, to be inserted into the underlying bone and/or a spacer member (not shown) and securelaminoplasty plate900 to the underlying lamina portion. A slottedsecurement opening945 inspacer portion910 can be provided to permit variable orientation and placement of one or more securement mechanisms relative to the underlying spacer member. Slottedsecurement opening945 allows infinitely variable placement of the fastener therealong. Other embodiments contemplated slottedsecurement opening945 with recesses forming one or more discrete fastener locations therealong.
• FIG. 14 is a perspective view of anotherembodiment laminoplasty plate1000 that can be employed, for example, with a hemilateral open door laminoplasty system, although application with other laminoplasty procedures is contemplated.Plate1000 can include aspacer portion1010 having afirst end1012 and asecond end1014. The longitudinal length ofspacer portion1010 can correspond to a desired separation distance between a posterior portion and an anterior portion of a divided lamina.
• Adjacentfirst end1012 is a first engagingportion1020 which can serve to reduce and/or prevent movement of a first divided lamina portion with respect tolaminoplasty plate1000 in at least two directions. First engagingportion1020 can include one or more lamina stabilizing flanges, such as firstlamina stabilizing flange1030 and secondlamina stabilizing flange1040. To reduce, restrain, and/or prevent movement of the lamina portion with respect tolaminoplasty plate1000, anyflange1030,1040 can be positioned and/or distributed about an expected longitudinal axis of the lamina portion, and/or can be of a sufficient length to at least partially capture or receive the lamina portion therebetween. Moreover, anyflange1030,1040 can be of sufficient length to include one ormore securement openings1032. Further, to grasp, grip, engage, crimp, clamp, capture, and/or restrain bone, anyflange1030,1040 can include abone engagement mechanism1042. In the illustrated embodiment,bone engagement mechanism1042 includes an elongated, pointed ridge that can bite into the adjacent bone. Other bone engagement mechanisms are contemplated, including one or more teeth, ridges and valleys, ledges, spikes, knurlings, friction increasing feature, and/or bone bearing surface, for example.
• First flange1030 of first engagingportion1020 can form anangle1091 with respect tospacer portion1010, which can approximately range in one embodiment from 5 to 85 degrees. In another embodiment, theangle1091 betweenfirst flange1030 andspacer portion1010 is in the range of 15 to 75 degrees. In another embodiment, theangle1091 betweenfirst flange1030 andspacer portion1010 is in the range of 30 to 60 degrees. In still another embodiment, theangle1091 betweenfirst flange1030 andspacer portion1010 is in the range of 40 to 50 degrees.
• First flange1030 can contact a posterior surface of the posterior portion of the divided lamina. Likewise,second flange1040, positioned medially offirst flange1030, can contact an anterior surface of the posterior portion of the divided lamina.Second flange1040 is shown extending transversely from and then longitudinally alongspacer portion1010.Second flange1040 can extend in any direction fromspacer portion1010, or can extend fromfirst flange1030. First andsecond flanges1030,1040 form a receptacle to contain a divided lamina portion and restrict its relative movement with respect toplate1000 in at least two directions.
• Second flange1040 includes a connectingportion1043 that formsangle1093 withspacer portion1010, and anend portion1045 that extends away fromfirst flange1030 at anangle1094. In one specific embodiment,angle1093 is about 67 degrees andangle1094 is about 8 degrees. Other embodiments contemplateangles1093 ranging from 45 degrees to 90 degrees, ranging from 25 degrees to 135 degrees, or ranging from 10 degrees to less than 180 degrees. Other embodiments contemplateangle1094 ranging from 15 degrees to 0 degrees, or ranging from 45 degrees to 0 degrees. It is also contemplated that theend portion1045 can converge towardfirst flange1030.
• The pair offlanges1030,1040 can cooperate to engage with the posterior portion of the divided lamina. In one embodiment,flanges1030,1040 can be bent, deformed, or moved toward one another to clamp, secure, and/or stabilize the posterior portion of the divided lamina. If a securement mechanism extending throughsecurement openings1032 were to pull loose, disengage, and/or detach from the posterior portion of the divided lamina, the laminoplasty plate could remain engaged to the posterior portion of the divided lamina by engagement offlanges1030,1040 with the divided lamina portion.
• Second end1014 ofspacer portion1010 include a secondengaging portion1050 having afirst flange1052 and asecond flange1054 with one or more securement holes1056.First flange1052 can be a bone ledge that is configured to provide a surface that faces and opposes an end surface of a dissected bone, such as the anterior portion (lateral mass) of the divided lamina.First flange1052 can be planar, flat, curved, curvilinear, undulating, contiguous, and/or discontiguous to conform to the profile of the bone against which it is positioned.Second flange1054 of second engagingportion1050 can form anangle1092 with respect tospacer portion1010, which can range in one embodiment from 5 to 85 degrees. In another embodiment,angle1092 betweensecond flange1054 andspacer portion1010 is in the range of 15 to 75 degrees. In another embodiment,angle1092 betweensecond flange1054 andspacer portion1010 is in the range of 30 to 60 degrees. In still another embodiment,angle1092 betweensecond flange1054 andspacer portion1010 is in the range of 40 to 50 degrees.
• Although not shown,first flange1052 and/orsecond flange1054 can include one or more additional bone engagement mechanism to grasp, grip, engage, crimp, clamp, capture, and/or restrain the adjacent bone of the divided lamina portion. Examples of such engagement mechanisms include at least one bone engagement tooth, notch, rib, groove, thread, spline, spike, knurling, ridge, valley, ledge, friction increasing feature, and/or bone bearing surface.
• Second engagingportion1050 oflaminoplasty plate1000 can be attached to, for example, the anterior portion of the divided lamina (and/or the facet) via one or more securement mechanisms that extend through securement holes1056. Even if these securement mechanisms loosen,first flange1052 and/orsecond flange1054 can resist second engagingportion1050 oflaminoplasty plate1000 and the anterior portion of the divided lamina from moving into the spinal canal or impinging upon the spinal cord. Moreover,first flange1052 can cooperate with the pair offlanges1030,1040 andspacer portion1010 to abut the divided ends of the lamina to prevent the divided lamina from moving into the “closed door” position. Thelamina engaging portions1020 and1050 also abut or engage the posterior surface of the divided lamina to resist the plate from drifting into the spinal canal and reducing the newly expanded cross-sectional area.
• Second flange1040 is shown extending tranversely fromspacer portion1010 and then generally parallel tofirst flange1030. One or more flanges could alternatively extend approximately perpendicular to and along one side offlange1030, thereby forming in conjunction withflange1030 an “L” shape. Firstlamina engaging portion1020 could also be provided with a “C” shape, such as discussed below with respect toFIGS. 16-19.
• Referring toFIG. 15, there is shownlaminoplasty plate2100. Except as noted,plate2100 can be similar toplate1000 discussed above.Plate2100 includes aspacer portion2110 with a secondlamina engaging portion2150 that can be similar to secondlamina engaging portion1050 discussed above. Adjacentfirst end2112 ofspacer portion2110 is a first engagingportion2120, which can include asingle flange2130, although other flange arrangements are also contemplated. At least one restrainingmember2180 is provided extending from an anteriorly oriented surface ofspacer portion2110. In certain embodiments,spacer member2190 can be shaped to receive restrainingmember2180, such as for example, by providingspacer member2190 with agroove2192 that corresponds to, for example, a rib-like restraining member2180.Restraining member2180 can include any form that resists relative movement betweenspacer portion2110 and one or moreadjacent spacer members2190, including, for example, one or more ribs, splines, webs, grooves, teeth, spikes, peaks, valleys, anchor, and/or roughened surfaces.
• FIG. 16 is a side view of anotherembodiment laminoplasty plate1100 that can be employed, for example, with a hemilateral open door laminoplasty system, although application with other laminoplasty procedures is contemplated.Plate1100 can include aspacer portion1110 and a second lamina engaging portion11150 that can be similar tospacer portion1010 and secondlamina engaging portion1050 discussed above forplate1000.Plate1100 includes a firstlamina engaging portion1144 having asecond flange1140 extending perpendicularly to afirst flange1130. Athird flange1142 extends perpendicularly tosecond flange1140 and generally parallel tofirst flange1130. As shown inFIG. 17,flanges1130,1140,1142 form a generally “C” shape to receive a portion of the divided lamina along its anterior, posterior and inferior surfaces. Accordingly, the posterior surface of the divided lamina can be in contact with or engaged withfirst flange1130.Second flange1140 can contact or engage the divided lamina portion on its bottom or inferior surface.Third flange1142 can engage or contact the divided lamina portion on its anterior surface. Other embodiments contemplate that thatsecond flange1140 is positioned along the superior surface of the divided lamina portion.
• FIG. 18 is a side view of anotherembodiment laminoplasty plate1300 that can be employed, for example, with a hemilateral open door laminoplasty system, although application with other laminoplasty procedures is contemplated.Plate1300 can include aspacer portion1310 and a secondlamina engaging portion1350 that can be similar tospacer portion1010 and secondlamina engaging portion1050 discussed above forplate1000.Plate1300 includes a firstlamina engaging portion1344 having asecond flange1342 extending perpendicularly tofirst flange1330. Athird flange1340 extends perpendicularly tofirst flange1330 and generally parallel tosecond flange1342. As shown inFIG. 19,flanges1330,1340 and1342 form generally a “C” shape to receive the a portion of the divided lamina. Accordingly, the superior surface of the divided lamina portion can be in contact with or engaged tosecond flange1342, the inferior surface of the divided lamina portion can be in contact with or engaged tothird flange1340, andfirst flange1330 can be in contact with the posterior surface of the divided lamina portion.
• The illustrated embodiments of the first lamina engaging portions inFIGS. 16-19 illustrate a rectangular “C” shape. Other embodiments contemplate interior surface profiles for the flanges of the lamina engaging portion that include rounded, circular, oval, non-circular, or polygonal interior surface profiles.
• FIG. 20 is a plan view of a vertebra that has been subjected to a French door laminoplasty procedure. The spinous process has been removed, and hinges have been formed in each lamina, and/or between each lamina and its respective facet. The hinged laminae are shown secured in their respective open positions by alaminoplasty plate1500 for a French door laminoplasty procedure.
• First lamina portion1510 is held apart a predetermined distance fromsecond lamina portion1520 byspacer portion1530 ofplate1500. The longitudinal length ofspacer portion1530 can correspond to a desired separation distance betweenfirst lamina portion1510 andsecond lamina portion1520.Spacer portion1530 can have sufficient structural strength to shield the spine and/or spinal canal in a manner approximately equivalent to, and/or better than, the previous bone structure.
• Adjacent one end ofspacer portion1530 is a firstlamina engagement portion1570, and adjacent the other end ofspacer portion1530 is a secondlamina engagement portion1560. Firstlamina engagement portion1570 includes a first plurality oflamina engagement flanges1540 and1550 for engagement withfirst lamina portion1510.Flanges1540,1550 can be positioned and/or distributed aboutfirst lamina portion1510 to engage at least two surfaces thereof which, in the illustrated embodiment, include the anterior and posterior surfaces.Lamina portion1510 can be received betweenflanges1540,1550 so thatlamina portion1510 is at least partially captured or located therebetween. Securement holes can be provided through anyflange1540,1550 to receive a securement mechanism. One or morebone engagement mechanisms1542 can be provided on one or both of theflanges1540,1550 to grasp, grip, engage, crimp, clamp, capture, and/or restrain thelamina portion1510 relative toplate1500. Secondlamina engagement portion1560 can be configured similarly to firstlamina engagement portion1570.
• FIG. 21 is a perspective view of anotherembodiment laminoplasty plate1600 for a French door laminoplasty procedure, although application with other laminoplasty procedures is contemplated.Laminoplasty plate1600 can prevent potential impingement on the spinal cord by either and/or both of the divided laminae of a particular vertebra subject to a French door laminoplasty.Plate1600 includes aspacer portion1610 having afirst end1612 and asecond end1614.Ends1612 and1614 can be longitudinally opposed onspacer portion1610. Firstlamina engagement portion1620 is adjacentfirst end1612, and secondlamina engagement portion1630 is adjacentsecond end1614.
• Firstlamina engagement portion1620 can include a firstlateral flange1622 and a firstmedial flange1626 forming a first bone grasping portion therebetween. Firstlateral flange1622 can also include one or more inwardly facingbone engagement mechanisms1624. Firstmedial flange1626 can include one or more outward facingbone engagement mechanisms1628. Thus, a pair of opposed bone engagement mechanisms can be supplied byflanges1622,1626.Bone engagement mechanisms1624,1628 can have similar or different geometric configurations. For example, either ofengagement mechanisms1624,1628 can be configured to contact a remaining portion of a divided lamina portion along a line of contact, as shown formechanism1624, at multiple points of contact, or at a single point of contact as shown formechanism1628. Once such contact is made, the mechanism can bite into or grip the divided lamina portion.
• Secondlamina engagement portion1630 can include a secondlateral flange1632 and a secondmedial flange1636 forming a second bone grasping portion therebetween.Second lateral flange1632 can include one or more inwardly facingbone engagement mechanisms1634. Secondmedial flange1636 can include one or more outward facingbone engagement mechanisms1638. Thus, a pair of opposed bone engagement mechanisms can be supplied byflanges1632,1636.Bone engagement mechanisms1634,1638 can have similar or different geometric configurations. For example, either ofengagement mechanisms1634,1638 can be configured to contact a divided lamina portion along a line of contact, as shown formechanism1634, at multiple points of contact, or at a single point of contact as shown formechanism1638. Once such contact is made, the engagement mechanism can bite into and/or grip the divided lamina portion.
• Secondlamina engagement portion1630 can be symmetrical to firstlamina engagement portion1620.Spacer portion1610,first engagement portion1620,second engagement portion1630, and/or anyflange1622,1626,1632, and/or1636 can include one ormore securement openings1640 to accommodate securement mechanisms. As viewed superiorly when installed,spacer portion1610 extends between the remaining divided laminae across the location of the removed spinous process, thereby maintaining a cross-sectional area of the spinal canal and providing a structural replacement for the removed bone.
• Firstlateral flange1622 of firstlamina engagement portion1620 can contact a laterally or posteriorly facing outer surface of a divided lamina portion. Likewise, the firstmedial flange1626 can contact a medially or anteriorly facing inner surface of the divided lamina portion.Flanges1622,1626 can be crimped and/or squeezed together to engagebone engagement mechanism1624,1628 with the divided lamina portion positioned therebetween, thereby clamping the divided lamina portion and preventing its movement and/or the closing of the first French door.
• Likewise, as viewed superiorly when installed, the secondlateral flange1632 of secondlamina engagement portion1630 can contact a laterally or posteriorly facing outer surface of a second divided lamina portion. The secondmedial flange1636 can contact a medially or anteriorly facing inner surface of the second divided lamina portion.Flanges1632,1636 can be crimped and/or squeezed together to engagebone engagement teeth1634,1638 with the second divided lamina portion therebetween, thereby clamping the second divided lamina and preventing its movement and/or the closing of the divided laminae.
• In an alternative embodiment (not shown), firstlamina engagement portion1620 can include a superior flange and a subjacent flange. The superior flange can be adapted to contact a superior surface of the first divided lamina portion. Secondlamina engagement portion1630 can be configured similarly. Alternatively, a “C” shape or enclosed shape arrangement can be utilized for one or bothlamina engagement portions1620,1630.
• A spacer member can be inserted between the first and second divided laminae. Such a spacer member can be secured via securement mechanism extending through securement holes (not shown) inspacer portion1610, firstlamina engagement portion1620, firstlateral flange1622, firstmedial flange1626, secondlamina engagement portion1630, secondlateral flange1632, and/or secondmedial flange1636. Thus, the spacer member can be held between the first and second divided laminae, and the ends of the laminae can be secured with respect to each other to prevent them from pulling apart. In applications where the spacer member is a fusion member, contact between the ends of the divided laminae and the fusion member can be maintained and protected byplate1600, promoting fusion.
• First and secondlateral flanges1622,1632 subtend anangle1695, andspacer portion1610 can be curved along aradius1697. In one specific embodiment,angle1695 is about 53 degrees, andradius1697 is about 21 millimeters. Other embodiments contemplateangle1695 ranging from 40 to 65 degrees, or from 0 degrees or less to 180 degrees or more. Other embodiments further contemplateother radii1697 forspacer portion1610. Also contemplated arespacer portions1610 that are not curved, but rather are straight or comprise a series of angularly offset linear portions or a series of curved portions.
• Medial flanges1626,1636 can extend parallel to one another as shown. Other embodiments contemplate thatmedial flanges1626,1636 diverge or converge relative to one another as they extend fromspacer portion1610.Medial flanges1626,1636 can each include a connectingportion1627,1637, respectively, and anend portion1629,1639, respectively.End portions1629,1639 extend from connectingportions1627,1637, respectively. In one embodiment, connectingportion1637 forms anangle1696 withend portion1639. Similarly, connectingportion1627 may form an angle withend portion1629. In one specific embodiment,angle1696 is about 120 degrees. Other embodiments contemplate other values forangle1696.
• FIG. 22 is a plan view of anotherembodiment laminoplasty plate2400 similar toplate1500 ofFIG. 20 andplate1600 ofFIG. 21.Plate2400 can include a spacer portion2430 having a firstlamina engaging portion2440 adjacent one end and a secondlamina engaging portion2450 adjacent its other end. One ormore securement openings2460 are provided in spacer portion2430, and one ormore securement openings2470 are provided in eachengagement portion2440,2450.Securement openings2460,2470 can allow one or more securement mechanisms (not shown), to be inserted into theunderlying lamina portions2410,2420 and/orspacer member2480 and securelaminoplasty plate2400 relative to thelamina portions2410,2420 and/orspacer member2480.Securement openings2460,2470 may further comprise a slot to permit variable orientation and placement of securement mechanisms relative to theunderlying lamina portions2410,2420 and/orspacer member2480.
• FIG. 23 is an elevational side view of an alternative embodiment of thelaminoplasty plate1600 ofFIG. 21.Laminoplasty plate2500 includes aspacer portion2510 andlamina engagement portions2530,2520 adjacent first andsecond end2514,2518, respectively.Securement opening2550 inspacer portion2510 may further comprise a slot to permit variable orientation and placement of the laminoplasty plate relative to the underlying spacer member.Engagement portions2520,2530 each include a plurality of flanges for engagement with the adjacent lamina portion.Lamina engagement portions2520,2530 each include a “C” shape for engagement with the anterior and posterior surfaces of the respective lamina portion, and also for engagement with one of the superior or inferior surfaces of the lamina portion.Securement openings2540 inengagement portions2520,2530 can allow one or more securement mechanisms (not shown) to be inserted into the underlying lamina portion. The open ends of each of the C-shaped lamina engagement portions allow for full surface area contact between a bone spacer positioned alongspacer portion2510 and the adjacent lamina portion.
• In another embodiment, on at least one end of theplate2500, the flanges can be replaced with a lamina engaging cup or annulus that completely or substantially surrounds an end of the divided lamina. Such a cup could advantageously reduce, restrain, and/or prevent radial movement of the end of the divided lamina portion up to360 degrees about an axis of the lamina, thereby further facilitating fusion and protection of the spinal canal. The cup could be crimped onto the end of the divided lamina portion for secure engagement therewith. Also, the cup could be lined and/or formed with one or more bone engagement mechanisms, such as for example, teeth, splines, threads, and/or grooves, for engagement with the lamina portion. The cup could include one or more securement openings through which a securement mechanism could be inserted to couple the cup and the underlying lamina portion. Further, the cup could include a bone ingrowth surface and/or a bone growth-inducing material.
• A further example of a laminoplasty plate having a lamina engagement cup is shown inFIGS. 24 and 25. Except as noted,laminoplasty plate1700 can be similar tolaminoplasty plate800 ofFIGS. 8, 9 and 10.Laminoplasty plate1700 includes alamina engaging cup1710 at an end ofspacer portion1720.Cup1710 can be bottomless, so that it resembles an elongated annulus, closed polygon, or an “O” shaped receptacle. The cross-section ofcup1710 can be any closed polygon, and thus can be circular, elliptical, racetrack shaped, rectangular, polygonal, etc. Moreover, the cross-section of the lamina can be shaped during surgery to fit within or provide a desired fit with a particular shape forcup1710.
• Cup1710 can also be provided with abottom surface1730 medially oriented with respect tospacer portion1720. An open bottom surface1739 forcup1710 can be desirable in procedures where fusion between the divided lamina portions is sought. The walls ofcup1710 can be adapted to slidably extend over both an end of the lamina and over the end of the spacer member, providing one or more contact points, lines, and/or surfaces betweencup1710 and the underlying lamina portion and the spacer member. Further,cup1710 can be adapted to contact, engage, grasp, and/or crimp both the lamina portion and the spacer member positioned therein, further resisting relative movement therebetween. In certain embodiments,plate1700 and/orcup1710 can be constructed of a resorbable material so that once fusion has occurred between the end of the divided lamina and the adjacent spacer member,plate1700 and/orcup1710 are resorbed.
• As a further exemplary embodiment, anadjustable cuff1910, as shown inFIGS. 26 and 27, is provided withlaminoplasty plate1900 and attached to an end ofspacer portion1920. Except as noted,laminoplasty plate1900 can be similar tolaminoplasty plate800 ofFIGS. 8, 9 and 10.Cuff1910 can be similar tocup1710, however the cross-section ofcuff1910 defines any open polygonal shape or curved shape. The walls ofadjustable cuff1910 can also be spread apart and adjusted to fit the bone of the underlying lamina portion.Cuff1910 can thus be side-loaded onto the divided lamina portion by separating the arms ofcuff1910. Moreover, the cross-section of the lamina can be shaped to fit within a particular shapedcuff1910. The gap between the arms ofcuff1910 can also be positioned for top or bottom loading on the divided lamina portion.Cuff1910 can be spring biased to return toward its natural state, and when separated and placed around the lamina portion, can clamp the lamina portion for engagement therewith.Cuff1910 and/or the divided lamina portion can also be sized so that a clamping force is not delivered to the divided lamina portion. Whether clamped or not clamped, engagement mechanisms and/or securement openings for securement mechanisms can be provided to engagecuff1910 to the divided lamina portion.
• FIGS. 28 and 29 are perspective views of another embodiment laminoplasty plate.Laminoplasty plate2700 is particularly suited for a hemilateral open door laminoplasty procedure, although application with other laminoplasty procedures is contemplated.Plate2700 includes aspacer portion2710 extending between afirst end2712 and asecond end2714.Spacer portion2710 includes a slottedsecurement opening2716.Securement opening2716 can have a recessedportion2718 adjacent the posteriorly oriented surface ofspacer portion2710. Recessedportion2718 allows a securement mechanism to be at least partially recessed therein for a lower profile relative tospacer portion2710. Recessedportion2718 can also include a spherical profile to mate with a spherical surface of securement mechanism for variable angle placement of the securement mechanism relative tospacer portion2710.Spacer portion2710 can have anenlarged portion2720 with a greater width aroundsecurement opening2716 to accommodatesecurement opening2716 while minimizing the width ofspacer portion2710 adjacentfirst end2712 and second2714.Enlarged portion2720 provides stiffness tospacer portion2710, while the reduced width at ends2712,2714 facilitate bending oflamina engagement portions2712,2714.
• Adjacentfirst end2712 is firstlamina engagement portion2730.Lamina engagement portion2730 includesfirst node2732 andsecond node2734.Nodes2732,2734 are aligned along an axis of afirst flange2748 extending fromfirst end2712.Nodes2732,2734 can be enlarged relative tofirst flange2748 to accommodate respective ones ofsecurement openings2736,2738.Securement opening2736 can have a recessedportion2740 adjacent the outwardly facing surface offirst node2732. Recessedportion2740 allows a securement mechanism to be at least partially recessed therein for a lower profile relative tofirst flange2748.Securement opening2738 can have a recessedportion2742 adjacent the outwardly facing surface ofsecond node2734. Recessedportion2742 allows a securement mechanism to be at least partially recessed therein for a lower profile relative tofirst flange2748. Recessedportions2740,2742 can also have a spherical profile to mate with a spherical surface of a securement mechanism positioned therein for variable angle placement of the securement mechanism relative tofirst flange2748.
• Adjacentsecond end2714 is a secondlamina engagement portion2750.Lamina engagement portion2750 includes asecond flange2768 having afirst node2752 and asecond node2754. First andsecond flanges2748,2768 can be arranged relative tospacer portion2710 in a manner similar to that discussed above with respect toplate800 ofFIGS. 8, 9 and 10.Nodes2752,2754 are aligned along an axis that extends transversely to the longitudinal axis ofsecond flange2768.Nodes2752,2754 can be enlarged relative toflange2768 to accommodate respective ones ofsecurement openings2756,2758.Securement opening2756 can have a recessedportion2760 adjacent the outwardly facing surface offirst node2752. Recessedportion2760 allows a securement mechanism to be at least partially recessed therein for a lower profile relative toflange2768.Securement opening2758 can have a recessedportion2762 adjacent the outwardly facing surface ofsecond node2754. Recessedportion2762 allows a securement mechanism to be at least partially recessed therein for a lower profile relative tosecond flange2768. Recessedportions2760,2762 can also have a spherical profile to mate with a spherical surface of securement mechanism for variable angle placement of the securement mechanism relative tosecond flange2768.
• In a further form of the plates discussed hereinabove, the number of flanges of at least one of the lamina engagement portions of the laminoplasty plates can be increased to provide additional points, lines, and/or surfaces of contact between the engagement portion and the divided lamina portion. The flanges can be distributed about the perimeter, or exterior surfaces of the divided lamina portion. Also, the flanges can be distributed evenly or unevenly about the perimeter of the divided lamina. Moreover, the distribution can be about a longitudinal axis of the divided lamina, about a line parallel to a longitudinal axis of the spacer portion, and/or about a line parallel to a longitudinal axis of the laminoplasty plate. Furthermore, one or more of the flanges can be flat and/or curved to accommodate the curvature of the outer surface of the divided lamina. The flanges can at least partially engage the divided lamina portion by contacting, attaching to, crimping or clamping about, and/or gripping the underlying lamina portion.
• FIG. 30 is a perspective view of a spacer member positionable between divided lamina portions.Spacer member2800 includes abody2802 extending between, in one operative orientations, aposterior surface2804 and ananterior surface2806.Body2802 further includes afirst end2808 and asecond end2810.First end2808 includes a concave surface that forms afirst receptacle2812 for at least partially receiving a first portion of a divided lamina. Similarly,second end2810 includes a concave surface that forms asecond receptacle2814 for at least partially receiving a second portion of a divided lamina.Surfaces2812,2814 can be comprised of a continuous curve, a series of curves, a series of linear segments, or a combination of curves and linear segments. In any event, thelamina engagement receptacles2812,2814 can receive the adjacent lamina portion. A large contact surface area is provided bysurfaces2812,2814 to facilitate engagement, and, ifspacer member2800 is a fusion member, a greater surface area for bone ingrowth.
• In use,anterior surface2806 is oriented toward the spinal canal, andposterior surface2804 is positioned adjacent a laminoplasty plate. Abore2816 opening atsurface2804 can receive a securement mechanism to securespacer member2800 to a laminoplasty plate.Spacer member2800 can be used with any of the laminoplasty plate embodiments discussed herein.Spacer member2800 can be attached to the laminoplasty plate and or to the adjacent divided lamina portions. It is also contemplated thatspacer member2800 can be used without a laminoplasty plate, but rather directly attached to the divided lamina portions. In one form,spacer member2800 is comprised of a material that can be formed or deformed to conform to the profile of the adjacent separation surfaces of the divided lamina portions.Surfaces2812,12814 can extend along posterior and anterior surfaces, for example, of the adjacent divided lamina portion to increase the surface area contact and provide a better fit therewith.Spacer body2802 could also be oriented so thatsurfaces2812,2814 extend along superior and inferior surfaces of the adjacent lamina portion.
• The spacer member embodiments discussed herein can be made of any bio-compatible material, including synthetic or natural autograft, allograft or xenograft tissues, and can be resorbable or non-resorbable in nature. Examples of tissue materials include hard tissues, connective tissues, demineralized bone matrix and combinations thereof. Further examples of resorbable materials are polylactide, polyglycolide, tyrosine-derived polycarbonate, polyanhydride, polyorthoester, polyphosphazene, calcium phosphate, hydroxyapatite, bioactive glass, and combinations thereof. Further examples of non-resorbable materials are non-reinforced polymers, carbon-reinforced polymer composites, PEEK and PEEK composites, shape-memory alloys, titanium, titanium alloys, cobalt chrome alloys, stainless steel, ceramics and combinations thereof and others as well.
• The laminoplasty plates discussed herein stabilize divided lamina portions to facilitate fusion with a spacer member placed between the divided lamina portions. The harvesting of a bone graft from the hip or pelvis of the patient can be avoided, reducing patient discomfort and pain. Spacer member displacement and/or spacer member malposition can be reduced or eliminated. Also, the possibility of intrusion of the divided lamina into the spinal canal can be reduced or eliminated, thereby reducing and/or eliminating the possibility of spinal cord impingement by either the plates or the spacer member. The increased stability provided by the plates to the divided lamina portions and to the spacer member can also reduce or eliminate the need for post-operative bracing.
• The laminoplasty plates discussed herein can be of a unitary construction, such that the spacer portion, lamina engaging portions and/or the flanges can be integral or formed from a single piece of material. Alternative embodiments contemplate that the components of the laminoplasty plate can be non-integral, and can be attached to and/or coupled to other components of laminoplasty plate. The laminoplasty plates can be dimensioned to accommodate the full variety of vertebrae that can be the object of a laminoplasty procedure, and also for multiple levels of laminoplasty along the spinal column. Embodiments of the laminoplasty plates contemplate a bendable spacer portion and/or one or more bendable lamina engagement portions in order to conform to the anatomy of a particular patient. The spacer portions and/or lamina engagement portions can also be pre-bent to accommodate patient anatomy based on pre-operative planning or anatomical considerations encountered during surgery.
• The laminoplasty plates can be constructed of any bio-compatible material(s) having sufficient strength to maintain the open position of the divided lamina. Suitable materials include certain metals, polymers, ceramics, and/or composites. The laminoplasty plates can also be constructed of a material that is thermosettable, settable, resorbable, radiolucent, and/or bone growth-inducing. In certain specific embodiments, one suitable material is titanium, such as a titanium alloy, for example CP Ti grade 2 alloy. Another suitable material can be a PAEK (polyaryletherketone) compound, particularly a PEEK (polyetheretherketone) compound.
• While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, and that all changes and modifications that come within the spirit of the invention are desired to be protected.

Claims (21)

1-87. (canceled)

88. A surgical method comprising:

removing a spinous process of a vertebra such that first and second laminae of the vertebra each include an inner surface, an outer surface and a cut surface extending from the inner surface to the outer surface; and

coupling a plate to the vertebra such that the cut surface of the first lamina is held apart a predetermined distance from the cut surface of the second lamina by a spacer portion of the plate.

89. The surgical method recited inclaim 88, further comprising:

cutting a first relief into the vertebra between the cut surface of the first lamina and a first pedicle of the vertebra to form a first hinge;

cutting a second relief into the vertebra between the cut surface of the second lamina and a second pedicle of the vertebra to form a second hinge; and

moving the cut surface of the first lamina relative to the cut surface of the second lamina.

90. The surgical method recited inclaim 89, wherein the first relief is cut into a medial cortical layer of the first lamina and the second relief is cut into a medial cortical layer of the second lamina.

91. The surgical method recited inclaim 89, wherein at least one of the reliefs has a depth of approximately 3 to 4 millimeters and a width of approximately 3 millimeters.

92. The surgical method recited inclaim 88, wherein the plate includes a first lamina engaging portion extending from a first end of the spacer portion and a second lamina engaging portion extending from an opposite second end of the spacer portion, the second lamina engaging portion being symmetrical to the first lamina engaging portion.

93. The surgical method recited inclaim 88, wherein the plate includes a first lamina engaging portion extending from a first end of the spacer portion and a second lamina engaging portion extending from an opposite second end of the spacer portion, the first lamina engaging portion including a first flange that directly engages the outer surface of the first lamina and a second flange that directly engages the inner surface of the first lamina, the second lamina engaging portion including a first flange that directly engages the outer surface of the second lamina and a second flange that directly engages the inner surface of the second lamina.

94. The surgical method recited inclaim 93, wherein the first flange of the first lamina engaging portion faces the second flange of the first lamina engaging portion and the first flange of the second lamina engaging portion faces the second flange of the second lamina engaging portion.

95. The surgical method recited inclaim 88, wherein the plate includes a first lamina engaging portion extending from a first end of the spacer portion and a second lamina engaging portion extending from an opposite second end of the spacer portion, the first lamina engaging portion including a first wall, a second wall and a third wall, the second wall extending from the first wall and a third wall extending from the second wall, an inner surface of the first wall facing the outer surface of the first lamina, an inner surface of the second wall facing the cut surface of the first lamina, an inner surface of the third wall facing the inner surface of the first lamina.

96. A surgical method comprising:

removing a spinous process of a vertebra to provide the vertebra with a first divided lamina portion and a second divided lamina portion; and

coupling a plate to the vertebra such that the first divided lamina portion is held apart a predetermined distance from the second divided lamina portion by a spacer portion of the plate.

97. The surgical method recited inclaim 96, wherein the plate includes a first lamina engaging portion extending from a first end of the spacer portion and a second lamina engaging portion extending from an opposite second end of the spacer portion, the first lamina engaging portion including a first lateral flange that contacts a laterally facing outer surface of the first divided lamina portion, the first lamina engaging portion including a first medial flange that contacts a medially facing inner surface of the first divided lamina portion.

98. The surgical method recited inclaim 97, further comprising crimping the flanges together with the first divided lamina portion therebetween.

99. The surgical method recited inclaim 97, wherein the second lamina engaging portion includes a second lateral flange that contacts a laterally facing outer surface of the second divided lamina portion, the second lamina engaging portion including a second medial flange that contacts a medially facing inner surface of the second divided lamina portion.

100. The surgical method recited inclaim 99, wherein the first lateral flange includes a bone engagement mechanism that faces the first medial flange and the second lateral flange includes a bone engagement mechanism that faces the second medial flange.

101. The surgical method recited inclaim 99, wherein the first medial flange includes a bone engagement mechanism that faces the first lateral flange and the second medial flange includes a bone engagement mechanism that faces the second lateral flange.

102. The surgical method recited inclaim 99, wherein the first lateral flange extends at an acute angle relative to the second lateral flange.

103. The surgical method recited inclaim 99, wherein the first medial flange extends parallel to the second medial flange.

104. The surgical method recited inclaim 99, wherein the medial flanges each include a connecting portion having a first end that directly engages the spacer portion and an opposite second end, an end portion extending from the second end, the end portion extending at an obtuse angle relative to the connecting portion.

105. The surgical method recited inclaim 96, wherein the plate includes a first lamina engaging portion extending from a first end of the spacer portion and a second lamina engaging portion extending from an opposite second end of the spacer portion, the first lamina engaging portion including a first lateral flange that contacts a posteriorly facing outer surface of the first divided lamina portion, the first lamina engaging portion including a first medial flange that contacts an anteriorly facing inner surface of the first divided lamina portion.

106. The surgical method recited inclaim 105, wherein the second lamina engaging portion includes a second lateral flange that contacts a posteriorly facing outer surface of the second divided lamina portion, the second lamina engaging portion including a second medial flange that contacts an anteriorly facing inner surface of the second divided lamina portion.

107. A surgical method comprising:

removing a spinous process of a vertebra to provide the vertebra with a first divided lamina portion and a second divided lamina portion; and

coupling a plate to the vertebra such that the first divided lamina portion is held apart a predetermined distance from the second divided lamina portion by a spacer portion of the plate,

wherein the plate includes a first lamina engaging portion extending from a first end of the spacer portion and a second lamina engaging portion extending from an opposite second end of the spacer portion,

wherein the first lamina engaging portion includes a first lateral flange that contacts a laterally facing outer surface of the first divided lamina portion, the first lamina engaging portion including a first medial flange that contacts a medially facing inner surface of the first divided lamina portion, the first lateral flange including a bone engagement mechanism that faces the first medial flange, the first medial flange including a bone engagement mechanism that faces the first lateral flange,

wherein the second lamina engaging portion includes a second lateral flange that contacts a laterally facing outer surface of the second divided lamina portion, the second lamina engaging portion including a second medial flange that contacts a medially facing inner surface of the second divided lamina portion, the second lateral flange including a bone engagement mechanism that faces the second medial flange, the second medial flange including a bone engagement mechanism that faces the second lateral flange,

wherein the first lateral flange extends at an acute angle relative to the second lateral flange,

wherein the first medial flange extends parallel to the second medial flange,

wherein the flanges of the first lamina engaging portion are crimped together with the first divided lamina portion therebetween, and

wherein the flanges of the second lamina engaging portion are crimped together with the second divided lamina portion therebetween.

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