Surgical connectors and instrumentation

This application is a reissue of U.S. Pat. No. 10,729,472, which was filed as U.S. Non-Provisional application Ser. No. 15/845,880 on Dec. 18, 2017, which is a divisional of U.S. Non-Provisional application Ser. No. 14/399,060 filed Nov. 5, 2014, whichissued as U.S. Pat. No. 9,844,398 andis a National Stage Entry under 35 U.S.C. § 371 of International Application No. PCT/US2013/040778 filed May 13, 2013, which claims priority to U.S. Provisional Application Ser. No. 61/646,030 filed May 11, 2012 and U.S. Provisional Application Ser. No. 61/798,414filed Mar. 15, 2013, which are incorporated by reference herein in their entirety.

The present disclosure relates to a system and technique for spinal surgery. Spinal implants, including connectors, hooks, screws and rods, are used to correct spinal deformities. Screws and connectors in combination with spinal rods can align and correct deformities in the natural spinal alignment as well as repair traumatic injury. Additionally, instrumentation for reduction of spinal rods into spinal pedicle screws is provided in the present disclosure.

Spinal fixation systems may be used in surgery to fix, adjust, and/or align the spinal column. One type of spinal fixation system employs a spinal rod for supporting the spine and fixing, adjusting, and/or aligning the spinal column into the desired orientation. Attachment of the spinal rod to the spinal column has been achieved using a variety of vertebral anchors. Vertebral anchors include screws, hooks, pins, and bolts used to engage the vertebrae and connect the spinal rod to different vertebrae.

The length and diameter of the spinal rod depends on the size and number of vertebrae to be held in a desired position by the spinal fixation system. The size of the spinal rod also depends on the region of the spine where the spinal fixation system is used. For example, in the cervical region of the spine, where the vertebrae tend to be smaller, a relatively smaller spinal rod is used. Conversely, in the thoracic region, where heavier loads are experienced and the vertebrae tend to be larger, a spinal rod having a relatively larger diameter is used. The cervico-thoracic junction of the spine is typically instrumented using spinal rods of two different diameters to accommodate anatomical differences between the cervical and thoracic spine regions. To accommodate a spinal fixation system including spinal rods having different sizes and configurations, a rod connector may be used to join a first spinal rod and a second spinal rod together. The rod connector may be a side-by-side connector, where the ends of the two spinal rods are placed side-by-side and connected using a connector that spans the two ends, or an axial connector, which aligns the axes of the two spinal rods and connects the ends of the spinal rods together along the axial direction. The plurality of possible spinal rod diameters in combination with the plurality of connector arrangements results in a surgeon typically requiring a vast array of connectors on hand in preparation for a given spinal surgery.

The spinal rods in a spinal fixation system may necessarily be bent to conform to a desired curvature of the spinal column in one or more of the anatomic planes as part of a spinal fixation or corrective surgery. Attachment of spinal rods to vertebral anchors such as screws, hooks, pins, and bolts may be complicated by differing curvature of the untreated spine and the curvature of the spinal rod. Instrumentation to force the spinal rod into engagement with the vertebral anchors may be used. Challenges arise in utilizing instrumentation to force the spinal rod into engagement with the vertebral anchors because the instrumentation generally must be releasably affixed to a previously implanted vertebral anchor and the locking mechanism on the vertebral anchor must be engaged while maintaining the spinal rod in the correct position. Simple engagement of the instrumentation with the vertebral anchor is desirable.

In one embodiment, a medical device having a spinal rod receiving channel and a rod retaining set screw is provided. The spinal rod receiving channel has at least a first circular hole, a second circular hole, and a third circular hole overlapping in parallel arrangement. The first circular hole, the second circular hole, and the third circular hole have offset centers disposed along a single line. The first circular hole forms an upper arc of the rod receiving channel; the second circular hole forms a middle arc of the rod receiving channel; the third circular hole forms a lower arc of the rod receiving channel; and the middle arc and the lower arc are connected by a connecting slant. The rod retaining set screw secures a spinal rod disposed in the spinal rod receiving channel into the medical device.

In another embodiment, a medical device having a plurality of spinal rod receiving channel and a plurality of retaining set screw is provided. The spinal rod receiving channels each have at least a first circular hole, a second circular hole, and a third circular hole overlapping in parallel arrangement. The first circular hole, the second circular hole, and the third circular hole have offset centers disposed along a single line. The first circular hole forms an upper arc of the rod receiving channel; the second circular hole forms a middle arc of the rod receiving channel; the third circular hole forms a lower arc of the rod receiving channel; and the middle arc and the lower arc are connected by a connecting slant. The rod retaining set screws secures a spinal rod disposed in each of the spinal rod receiving channels into the medical device.

In another embodiment, a medical device having a spinal rod receiving channel, a rod retaining set screw, and a hook for engagement with the lamina of a vertebrae is provided. The spinal rod receiving channel has at least a first circular hole, a second circular hole, and a third circular hole overlapping in parallel arrangement. The first circular hole, the second circular hole, and the third circular hole have offset centers disposed along a single line. The first circular hole forms an upper arc of the rod receiving channel; the second circular hole forms a middle arc of the rod receiving channel; the third circular hole forms a lower arc of the rod receiving channel; and the middle arc and the lower arc are connected by a connecting slant. The rod retaining set screw secures a spinal rod disposed in the spinal rod receiving channel into the medical device.

In another embodiment, a medical device having a spinal rod receiving channel, a rod retaining set screw, and a lateral connector rod with a diameter of approximately 4.75 mm or 5.5 mm for engagement with a spinal pedicle screw is provided. The spinal rod receiving channel has at least a first circular hole, a second circular hole, and a third circular hole overlapping in parallel arrangement. The first circular hole, the second circular hole, and the third circular hole have offset centers disposed along a single line. The first circular hole forms an upper arc of the rod receiving channel; the second circular hole forms a middle arc of the rod receiving channel; the third circular hole forms a lower arc of the rod receiving channel; and the middle arc and the lower arc are connected by a connecting slant. The rod retaining set screw secures a spinal rod disposed in the spinal rod receiving channel into the medical device.

A another embodiment, a medical device having a first cross connector rod hook and a second cross connector hook for securing spinal rods, two conical screw receiving ports, and two rod retaining conical screws is provided. The first and second cross connector rod hooks have at least a first circular bore, a second circular bore, and a third circular bore which in combination form a hook with an open portion. The first circular bore, the second circular bore, and the third circular bore are parallel and have offset centers disposed along a single line. The first circular bore forms an upper arc of the cross connector rod hook; the second circular bore forms a middle arc of the cross connector rod hook; the third circular hole forms a lower arc of the cross connector rod hook; and the middle arc and the lower arc are connected by a connecting slant. The rod retaining conical screws secure a spinal rod disposed in the first and second cross connector rod hooks into the medical device.

In another embodiment, a medical device having a first cross connector rod hook and a second cross connector hook for securing spinal rods, two conical screw receiving ports, and two rod retaining conical screws is provided. The first and second cross connector rod hooks have at least a first circular bore, a second circular bore, and a third circular bore which in combination form a hook with an open portion. The first circular bore, the second circular bore, and the third circular bore are parallel and have offset centers disposed along a single line. The first circular bore forms an upper arc of the cross connector rod hook; the second circular bore forms a middle arc of the cross connector rod hook; the third circular hole forms a lower arc of the cross connector rod hook; and the middle arc and the lower arc are connected by a connecting slant. The rod retaining conical screws secure a spinal rod disposed in the first and second cross connector rod hooks into the medical device. The medical device further has a first linkage, a second linkage, a pivot post, and a midline nut. The first linkage comprises the first cross connector hook, one of the conical screw receiving ports and a bi-axial cross connector extension rod. The second linkage comprises the second cross connector hook, one of the conical screw receiving ports and a bi-axial cross connector. When assembled the bi-axial cross connector extension rod is disposed in the bi-axial cross connector extension rod channel, the linkage retaining orifice is disposed over the threaded post, and the midline nut is disposed on the threaded post.

In another embodiment, a medical instrument having a rod reduction assembly and a pedicle screw engaging assembly is provided. The rod reduction assembly comprises a rod reduction sleeve, a reduction rod, and an advancing knob. The reduction sleeve comprises a hollow, cylindrical shaped body having an internal reduction sleeve channel, reduction rod engagement slots on a first end, and rod engagement radii on a second end. The reduction rod comprises external reduction rod threads on a first end and the advancing knob comprises internal threads matched to the external reduction rod threads. The reduction rod has first and second extenders extending radial from the outer surface proximal a second end which engage with the reduction rod engagement slots. The pedicle screw engaging assembly has fingers for engagement with the head of a pedicle screw, finger cam pins, an inner tube, and a release ring. The fingers each comprise a finger hook having a finger hook undercut, a finger slot, and a finger aperture. The finger slot have a first end distal the finger hook with a width sufficient to permit finger cam pin to slide through but not enough for substantial lateral movement transverse to the sliding direction and a second end proximal the finger hook with a larger width to form a clearance fit with the finger cam pin. The inner tube comprises a hollow, cylindrical body having a first inner tube end and a second inner tube end, a first inner tube slot and a second inner tube slot diametrically opposed across the cylindrical body, and a first finger slot and a second finger slot diametrically opposed across the cylindrical body. The first inner tube slot and the second inner tube slot are open toward the second inner tube end and the fingers are disposed in the first finger slot and the second finger slot with the fingers oriented to dispose the finger hooks proximal the second inner tube end and the finger hook undercuts toward the interior of the inner tube. Movement of the release ring from a first position to a second position moves the finger cam pins from the second end of the finger slot to the first end of the finger slot thereby positioning the fingers for insertion of the head of a pedicle screw.

Referring initially to, an isometric view of a wedding band inline dual diameter connectorwith spinal rods,disposed therein. The wedding band inline dual diameter connectorillustrated inspecifically has a 5.5 mm diameter spinal rodand a 4.75 mm diameter spinal roddisposed therein.

The wedding band inline dual diameter connectorconnects two spinal rods,in a substantially parallel orientation. The wedding band inline dual diameter connectorallows a surgeon performing a spinal surgery to utilize multiple spinal rods,along the length of the spine in lieu of a single long rod. Use of multiple spinal rods,allows for different diameter spinal rods to be used along the length of the spine based on changes in anatomy. Changing diameters of spinal rods,also allows for the mechanical properties, such as stiffness, of the fixation or deformity correction to be varied along the length of the patient's spine.

In addition to different sized spinal rods, multiple spinal rods of the same diameter may be connected together. For example, two 5.5 mm diameter spinal rodsmay be joined. Additionally, two 4.75 mm diameter spinal rodsmay be joined.

Referring to, an embodiment of a wedding band inline dual diameter connector, rod receiving channelsare shown. The specific and special geometry of the rod receiving channelsallows for both 5.5 mm diameter spinal rodsand 4.75 mm diameter spinal rodsto be secured in the rod receiving channels. The rod receiving channelsare substantially a composite of three circular through holes. The resulting rod receiving channelis comprised of one upper arc, two middle arcs, two connecting slants, and one lower arc. The upper arcpreferably has an approximately 2.76 mm to approximately 3.02 mm radius. For example, a radius of 2.890 mm. The middle arcpreferably has an approximately 2.595 mm to approximately 2.855 mm radius. For example, a radius of 2.725 mm. The lower arcpreferably has an approximately 1.87 mm to approximately 2.13 mm radius. For example, a radius of 2.000 mm. The connecting slantpreferably has a length of approximately 0.638 mm to approximately 0.898 mm. For example, a length of 0.768 mm. The centers of the upper arc, the middle arc, and the lower arcare co-linear. The center of the middle arcis located between the center of the upper arcand the lower arc. The centers of the upper arcand middle arcare preferably separated by approximately 1.00 mm to approximately 1.07 mm. The centers of the lower arcand middle arcare preferably separated by approximately 1.02 mm to approximately 1.09 mm. The angle of the connecting slantis preferably approximately 42° to approximately 44° from the line formed by the centers of the upper arc, the middle arc, and the lower arc.

Set screw receiving portsare positioned in alignment with the rod receiving channels. The set screw receiving portsare configured to engage with a set screwthrough threaded engagement. Set screw receiving threadsare positioned on the interior surface of the set screw receiving portsto engage with external threads on set screw. Set screwsare threaded into the wedding band inline dual diameter connectorand abutted against the spinal rods,to secure the spinal rods into the wedding band inline dual diameter connector.

In an embodiment of the wedding band inline dual diameter connector, a rod receiving channel reliefis disposed opposite each set screw receiving port. The rod receiving channel reliefin an embodiment is a circular through hole diametrically opposite the set screw receiving port.

Referring again to, the spinal rods,are illustrated as translucent to allow the interface between the wedding band inline dual diameter connectorand the spinal rods to be seen. The 5.5 mm diameter spinal rodcontacts the wedding band inline dual diameter connectorin a 5.5 mm contact areademarcated as a shaded region. The 4.75 mm diameter spinal rodcontacts the wedding band inline dual diameter connectorin a 4.75 mm contact areademarcated as a second shaded region. Both the 5.5 mm contact areaand the 4.75 mm contact areaare mirrored on the opposing surface of the respective spinal rod,and connector interface (not shown).

In a specific embodiment the 5.5 mm contact areais approximately 32.08 mmand the 4.75 mm contact areais approximately 7.44 mm. These contact areas can vary according to the limits of the full range of disclosed embodiments of the rod receiving channels.

Referring toand, a top profile and end profile respectively of an inline dual diameter connectoris shown. The inline dual diameter connectorhas the same closed rod receiving channelprofile as described for the wedding band inline dual diameter connector. In the inline dual diameter connector, a single closed rod receiving channelpasses along the entire longitudinal axis. This arrangement allows two spinal rods,to be abutted end to end without any lateral shift required.

Referring to, a domino inline dual diameter connectoris shown in a top profile view. The domino inline dual diameter connectoralso has a front profile matching that of the wedding band inline dual diameter connectoras shown inand. The arrangement of the domino inline dual diameter connectoris that of two inline dual diameter connectorsdisposed side by side.

It is envisioned that four spinal rods,can be secured together, wherein each single spinal rod is secured by an individual set screwdisposed in each of the four set screw receiving ports. It is also envisioned that two spinal rods,can be secured in a parallel orientation with two set screwssecuring each spinal rod. The domino inline dual diameter connectormay secure any combination of 4.75 mm diameter spinal rodsand 5.5 mm diameter spinal rodsat each of the set screw receiving ports. Non-limiting examples include two 4.75 mm diameter spinal rodssecured with two set screwssecuring each rod, a single 4.75 mm diameter spinal rodand a single 5.5 mm diameter spinal rodwith two set screwssecuring each rod, two 4.75 mm diameter spinal rodsand two 5.5 mm diameter spinal rodssecured with one set screwsecuring each rod, two 4.75 mm diameter spinal rodsand one 5.5 mm diameter spinal rodsecured with one set screwsecuring each 4.75 mm diameter spinal rod and two set screwssecuring the 5.5 mm diameter spinal rod, and two 5.5 mm diameter spinal rodsand one 4.75 mm diameter spinal rodsecured with one set screwsecuring each 5.5 mm diameter spinal rod and two set screwssecuring the 4.75 mm diameter spinal rod.

Referring toand, a front profile view and a side profile view respectively of a closed laminar hook. The closed laminar hookcomprises a set screw receiving port, a closed rod receiving channel, and a hook blade. The hook blademay be of varying widths and lengths.

Other standard styles and sizes of hooks are envisioned. Non-limiting examples include closed and open pedicle hooks, closed laminar hooks, open laminar hooks, open thoracic hooks, open offset thoracic hooks, and open offset lumbar hooks.

Referring to, an isometric view of an open laminar hook. The open laminar hookcomprises an open rod receiving saddleand a hook blade. The hook blademay be of varying widths and lengths.

The open rod receiving saddlecomprises the same geometry as closed rod receiving channelexcept the upper arcis not present and a portion of middle arcmay also be not present. In an embodiment, the upper threaded portion of the open laminar hookmay replicate the geometry of any uniaxial or polyaxial spinal screw known to one skilled in the art. Additionally, in an embodiment of the open laminar hookthe external geometry may replicate the external shape and geometry of any uniaxial or polyaxial spinal screw known to one skilled in the art.

Referring toand, a top and front view respectively of a fixed cross connector. The fixed cross connectorcomprises a cross connector rod hookand a conical screwat each end. The conical screwretains a spinal rod,in the respective cross connector rod hook. The distance between the two cross connector rod hooksmay be varied to allow the fixed cross connectorto be attached to spinal rods,at various lateral spacing. In selected embodiments the distance between the centers of the two cross connector rod hooksis between approximately 10 mm and approximately 40 mm. In a further selected embodiment the distance between the centers of the two cross connector rod hooksis between approximately 14 mm and approximately 36 mm. Non-limiting examples include a distance between the centers of the two cross connector rod hooksof approximately 14 mm, approximately 16 mm, approximately 18 mm, approximately 20 mm, approximately 22 mm, approximately 24 mm, approximately 26 mm, approximately 28 mm, approximately 30 mm, approximately 32 mm, approximately 34 mm, and approximately 36 mm.

Referring to, an isometric view of a further embodiment of the fixed cross connector. In this embodiment the ends of the fixed cross connectorare connected by a fixed cross connector extension rod. The fixed cross connector extension rodmay be of varying lengths to provide a fixed cross connectorconfigured to attach to spinal rods,at various lateral spacing. In selected embodiments the distance between the centers of the two cross connector rod hooksis between approximately 10 mm and approximately 40 mm. In a further selected embodiment the distance between the centers of the two cross connector rod hooksis between approximately 14 mm and approximately 36 mm. Non-limiting examples include a distance between the centers of the two cross connector rod hooksof approximately 14 mm, approximately 16 mm, approximately 18 mm, approximately 20 mm, approximately 22 mm, approximately 24 mm, approximately 26 mm, approximately 28 mm, approximately 30 mm, approximately 32 mm, approximately 34 mm, and approximately 36 mm. The fixed cross connector extension rodmay also be curved or angulated to allow fixation to spinal rods,which are not in parallel alignment. The conical screw receiving portaccepts a conical screwfor securing a spinal rod,in the respective cross connector rod hook.

Referring to,, and, a front profile, top profile, and an isometric view respectively of a closed lateral connector. The closed lateral connectorcomprises a lateral connector rod, a set screw receiving port, and a closed rod receiving channel. The lateral connectormay be affixed to a polyaxial screw[shown in] or a uniaxial screw with the lateral connector roddisposed in the screw saddle. The lateral connector rodis sized to match a standard spinal rod,. The lateral connector rodis preferably circular and approximately 4.75 mm or approximately 5.5 mm in diameter. The lateral connector rodmay also be varying lengths. The lateral connector rodis preferably approximately 15 mm to approximately 80 mm in length and more preferably approximately 20 mm to approximately 60 mm in length. Non-limiting examples include a lateral connector rodwith a length of approximately 20 mm, approximately 30 mm, approximately 40 mm, and approximately 60 mm.

Referring to, a front profile view of a bi-axial cross connector. The bi-axial cross connectorcomprises a first linkage, a second linkage, a pivot post, a midline nut, and a pair of conical screws. The first linkageand the second linkagecan extend along a first axis to lengthen the bi-axial cross connector. Adjustment of the length along the first axis allows the bi-axial cross connectorto be affixed to spinal rods,laterally spaced at any distance along a continuum. This is in contrast to a fixed cross connector, wherein the spinal rods must be laterally spaced at approximately one of a finite number of predetermined distances. The first linkageand second linkagemay also rotate relative to each other about the first axis. Rotation of the first linkageand second linkageabout the first axis allows the bi-axial cross connectorto be affixed to spinal rods,which are skewed in the sagittal plane. The first linkageand the second linkageare also angulated about a second axis perpendicular to the first axis. Angulation of the first linkageand the second linkageabout the second axis allows the bi-axial cross connectorto be affixed to spinal rods,which are skewed in the coronal plane.

Adjustment of the length of the bi-axial cross connectoralong the first axis allows the bi-axial cross connectorto be affixed to spinal rods,laterally spaced at any distance along a continuum within predetermined ranges.

Referring to, the first linkagecomprises a cross connector rod hook, a bi-axial cross connector extension rod, and a bi-axial cross connector extension rod limiter. Cross connector rod hookcomprises the same geometry as closed rod receiving channelexcept the upper arcis not present and a portion of middle arcmay also be not present. The bi-axial cross connector extension rodis a round shaft with the bi-axial cross connector extension rod limiterdisposed on the end. The bi-axial cross connector extension rod limiterhelps prevent the bi-axial cross connector extension rodfrom disengaging from the pivot postduring manipulation of the bi-axial cross connector. The bi-axial cross connector extension rodis preferably approximately 10 mm to approximately 40 mm in length and more preferably approximately 17 mm to approximately 32 mm in length. The bi-axial cross connector extension rodis preferably approximately 3.5 mm to approximately 4.5 mm in diameter and more preferably approximately 3.9 mm to approximately 4.1 mm in diameter. For example, the bi-axial cross connector extension rodmay be 24 mm in length and 3.98 mm in diameter.

Referring toand, a side profile and front profile respectively of the pivot post. The pivot postcomprises a bi-axial cross connector extension rod channel, a threaded post, and a linkage retaining shoulder. The bi-axial cross connector extension rod channelis configured to allow the bi-axial cross connector extension rodand the bi-axial cross connector extension rod limiterto pass through unimpeded when the bi-axial cross connector extension rod is in contact with a first surface. Conversely, the bi-axial cross connector extension rod channelis configured to prohibit the bi-axial cross connector extension rodand the bi-axial cross connector extension rod limiterto pass through unimpeded when the bi-axial cross connector extension rod is in contact with a second surface, as the bi-axial cross connector extension rod limiter catches on the pivot post. The threaded postcomprises threads configured to engage with internal threads on the midline nut.

The first surfaceof the bi-axial cross connector extension rod channelof the pivot postpreferably is an arc with a diameter of approximately 0.6 to approximately 1.4 mm larger than the diameter of the bi-axial cross connector extension rod. The second surfaceof the bi-axial cross connector extension rod channelof the pivot postpreferably is an arc with a diameter of approximately 0.03 to approximately 0.30 mm larger than the diameter of the bi-axial cross connector extension rod. For example, as in the previous example, the bi-axial cross connector extension rodmay be 3.98 mm in diameter and the diameter of the arc of the first surfacemay be 4.98 mm and the diameter of the second surfacemay be 4.02 mm.

Referring toand, a front profile view and a top profile view respectively of the second linkage. The second linkagecomprises a cross connector rod hook, a conical screw receiving portwith conical screw receiving threads, and a bi-axial cross connector extension plankhaving a linkage retaining orifice. The linkage retaining orificeengages with the linkage retaining shoulderof the pivot post. The bi-axial cross connector extension plankis a flat strip extending away from the conical screw receiving portand cross connector rod hook. The bi-axial cross connector extension plankis preferably approximately 10 mm to approximately 40 mm in length and more preferably approximately 17 mm to approximately 32 mm in length. The length of the bi-axial cross connector extension plankis the length of the thinned portion of the second linkage. For example, the bi-axial cross connector extension plankmay be approximately 17 mm in length, approximately 18 mm in length, approximately 20 mm in length, approximately 24 mm in length, and approximately 32 mm in length.

When assembled, the midline nutpresses the second linkagetoward the linkage retaining shoulderwhich in turn presses the second linkage into the bi-axial cross connector extension rodwhich is passed through the bi-axial cross connector extension rod channel. The compressive force of the midline nut, in conjunction with frictional forces, prevent the bi-axial cross connectorfrom extending along the first axis, rotating about the first axis, or angulating about the second axis.

Referring again to, a front profile of the bi-axial cross connectorin an extended configuration. The bi-axial cross connectorcan secure both the 5.5 mm diameter spinal rodand the 4.75 mm diameter spinal rod. The 5.5 mm diameter spinal rodis shown inin the cross connector rod hookin an unsecured configuration as the conical screwis not fully advanced and pressing the spinal rod into the cross connector rod hook.

Referring to, a top profile of the bi-axial cross connectorin a retracted configuration. The conical screwhas a hexalobular internal driving feature.

In an embodiment of the bi-axial cross connector, the range of adjustment afforded by the different lengths of the bi-axial cross connector extension rodand the bi-axial cross connector extension plankallows for the bi-axial cross connectorto be adjusted from approximately 30 mm to approximately 70 mm spacing between the centerlines of spinal rods/disposed in the cross connector rod hooks. In an embodiment of the bi-axial cross connector, spacing between the centerlines of spinal rods/disposed in the cross connector rod hooksmay be adjusted from approximately 34 mm to approximately 37 mm. In a further embodiment of the bi-axial cross connector, spacing between the centerlines of spinal rods/disposed in the cross connector rod hooksmay be adjusted from approximately 35 mm to approximately 39 mm. In a further embodiment of the bi-axial cross connector, spacing between the centerlines of spinal rods/disposed in the cross connector rod hooksmay be adjusted from approximately 37 mm to approximately 43 mm. In a further embodiment of the bi-axial cross connector, spacing between the centerlines of spinal rods/disposed in the cross connector rod hooksmay be adjusted from approximately 41 mm to approximately 51 mm. In a further embodiment of the bi-axial cross connector, spacing between the centerlines of spinal rods/disposed in the cross connector rod hooksmay be adjusted from approximately 49 mm to approximately 67 mm. The combination of the multiple specifically disclosed embodiments of the bi-axial cross connectorallows for a bi-axial cross connectorto be selected suitable for securing spinal rods/spaced anyplace along the continuum of approximately 34 mm to approximately 67 mm.

Referring to, an embodiment of a bi-axial cross connector. The bi-axial cross connectorcomprises a first linkage, a second linkage, a midline locking post, a midline locking screw, and a pair of conical screws. The first linkageand the second linkagecan extend along a first axis to lengthen the bi-axial cross connector. Adjustment of the length along the first axis allows the bi-axial cross connectorto be affixed to spinal rods,laterally spaced at any distance along a continuum. This is in contrast to a fixed cross connector, wherein the spinal rods must be laterally spaced at approximately one of a finite number of predetermined distances. The first linkageand second linkagemay also rotate relative to each other about the first axis. Rotation of the first linkageand second linkageabout the first axis allows the bi-axial cross connectorto be affixed to spinal rods,which are skewed in the sagittal plane. The first linkageand the second linkageare also angulated about a second axis perpendicular to the first axis. Angulation of the first linkageand the second linkageabout the second axis allows the bi-axial cross connectorto be affixed to spinal rods,which are skewed in the coronal plane.

Referring to, the first linkagecomprises a cross connector rod hook, a bi-axial cross connector extension rod, and a bi-axial cross connector extension rod limiter. Cross connector rod hookcomprises the same geometry as closed rod receiving channelexcept the upper arcis not present and a portion of middle arcmay also be not present. The bi-axial cross connector extension rodis a round shaft with the bi-axial cross connector extension rod limiterdisposed on the end. In an embodiment, the bi-axial cross connector extension rod limiteris a pin projecting beyond the diameter of the bi-axial cross connector extension rod. The bi-axial cross connector extension rod limiterhelps prevent the bi-axial cross connector extension rodfrom disengaging from the midline locking postduring manipulation of the bi-axial cross connector. The bi-axial cross connector extension rod limiteris preferably installed in the bi-axial cross connector extension rodsubsequent to passing though the midline locking postduring the manufacturing and assembly process. The bi-axial cross connector extension rod limiteris preferably sized such that removal of the bi-axial cross connector extension rodfrom the midline locking postis not feasible.

Referring to, an embodiment of the midline locking postused in the embodiment of the bi-axial cross connectorshown inis shown. The midline locking postcomprises a bi-axial cross connector extension rod passage, a threaded locking screw receiver, and a locking post retention flange. The bi-axial cross connector extension rod passageis configured to allow the bi-axial cross connector extension rodto pass through unimpeded but prevent the bi-axial cross connector extension rod limiterfrom passing through. The threaded locking screw receivercomprises internal threads configured to engage with external threads on the midline locking screw. The locking post retention flangeretains the midline locking postin the second linkage prior to securing with the midline locking screw.

The second linkagecomprises a cross connector rod hook, a conical screw receiving portwith conical screw receiving threads, and a bi-axial cross connector extension plankhaving a linkage retaining orifice. The linkage retaining orificehas a linkage retention flangedisposed around the periphery of the linkage retaining orifice. The linkage retention flangeengages with the locking post retention flange.

When assembled, the midline locking screwpulls the midline locking postupward. The movement of the midline locking postmoves the first linkageupward as well and compresses the first linkageagainst the second linkage. The compressive force of the midline locking screwand the midline locking postpulling the second linkageand the first linkagetogether, in conjunction with frictional forces, prevent the bi-axial cross connectorfrom extending along the first axis, rotating about the first axis, or angulating about the second axis.

Referring to, a front profile of a polyaxial screw. The polyaxial screwcomprises a screw saddlefor receiving a spinal rod,or lateral connector rodfor example. The rod receiving geometry of the screw saddleis envisioned being configured to match the rod receiving geometry of the open rod receiving saddleof the open laminar hookfor acceptance of multiple diameter spinal rods including a 5.5 mm diameter spinal rodor a 4.75 mm diameter spinal rod. Uniaxial screws with a similar rod receiving geometry for securing multiple diameter spinal rods,are also envisioned.

While reference is made throughout this disclosure to dual-diameter connectors, dual-diameter hooks, and dual-diameter screws, it is envisioned that the technique used to allow acceptance of two diameters of rods can be modified to allow three or more diameters of rods.

Referring to, a rod reduction deviceis shown.is a longitudinal cross sectional view of reduction devicetaken along section line, N-N. In the illustrative embodiment shown, reduction deviceincludes an housing tube, advancing knob, reduction rod, cap, inner tube, retractor sleeve, reduction sleeve, release ring, release ring screw, fingers, finger springs, spring hinge pins, finger cam pins, finger hinge pins, weld sleeve, release spring, a plurality of ball bearings, and finger cover. When assembled together, these components form reduction device, which comprises a hollow, cylindrical shaped assembly having a first endand a second end. First endincludes a first assembly opening, and second endincludes a second assembly opening. Each of the components set forth above will be individually described below herein and shown in separate figures. In addition, it will be shown and described below herein how each of the components of reduction deviceare interconnected and, once assembled, how reduction deviceworks in operation.

Referring to, housing tubeof reduction deviceis shown. Housing tubecomprises a hollow, housing tube body, having a housing tube first endand a second endopposite housing tube first end. Housing tube first endis shaped. In this example, housing tube first endhas a hexagonal shape. Additionally, in this example housing tube first endcomprises housing tube engagement slots. Also, housing tube first endincludes internal housing tube threads. Housing tube first endalso comprises a first housing tube opening, and second endcomprises a second housing tube opening. Housing tube bodyincludes an internal housing tube channelthat connects first and second outer tube openings/, respectively. Housing tube bodyincludes at second endtwo diametrically opposed housing tube slots, each running from the second endlongitudinally along at least a portion of housing tube body. Housing tube slotsfurther include a narrow portionconnected to a wide portion.

Housing tube bodyalso includes diametrically opposed second housing tube slotsdisposed at second end, but circumferentially offset 90° from housing tube slots. Second housing tube slotsrun from second endlongitudinally along at least a portion of housing tube body. Optionally, housing tube bodyincludes a gripping section such as a medium diamond knurletched into a surface of housing tube body.