Patent Description:
Surgical procedures sometimes require the use of a bone implant, a portion of which is attached to a bone inside an incision, and a portion of which extends outside of the patient's body through the incision. For example, a bone implant can be attached to a bone inside an incision, and some type of implant extension can extend outside of the incision. The term "extension" as used herein can refer to any elongated body projecting from a bone implant outside of the patient's body, including but not limited to a long section of the implant that is designed to be broken off of the implant after a procedure is completed, or a separate attachment such as a tube that is detachably connected to the bone implant. One purpose of an extension is to provide a structure than can distribute force on the implant and bone to which the implant is anchored. For example, a force applying instrument can be attached to an extension and manipulated in some manner to apply force to the bone through the extension and bone implant. Such force can be applied to the extension and implant to correct the position or orientation of the bone relative to other bones.

Bone implants with extensions can be used in procedures to correct abnormal curvatures of the spine. In spinal surgery, a pair of bone anchors referred to as "pedicle screws" are attached to each side of a vertebral body. Pedicle screws can be used to apply force to a vertebral body as well as connect the vertebral body to fixation elements, such as a fixation rods. There is often a need to correct abnormal curvatures of the spine by applying a force to multiple pedicle screws at the same time. For example, there may be a need to apply a corrective force to multiple pedicle screws attached to a single level in the spine. At other times, there may be a need to apply corrective force or forces to multiple levels at the same time. In the latter case, there may be a need to apply one force to a pair of pedicle screws at one level, while simultaneously applying another force to another pair of pedicle screws at a different level.

It can be very difficult to apply forces to multiple extensions in a coordinated manner. Each extension extends from the patient at its own unique angle and orientation. Therefore, each extension may require an adjustment force applied in a specific direction that is different from a neighboring extension. The spacing between extensions can also be very limited, making it difficult to attach separate instruments to each extension. Moreover, a procedure that adjusts multiple levels at the same time can be very difficult, as it can require different forces to be applied to four or more extensions simultaneously, in which case two or more surgeons may need to work together in a carefully coordinated manner.

<CIT> discloses a surgical instrumentation according to the preamble of claim <NUM>.

A transverse coupling which is not part of a surgical instrumentation for vertebral derotation is disclosed in <CIT>.

The inventors have developed an instrument that allows surgeons to apply forces to multiple bone implants in a coordinated but simplified manner. This is achieved by multiple extensions and a transverse coupler or bridge that interconnects the multiple extensions together. The transverse coupler can be detachably connected to multiple extensions and allow an adjustment force to be applied to the multiple bone implants in a coordinated manner. This permits the surgeon to apply a single adjustment force through the transverse coupler to multiple bone implants at the same time.

The transverse coupling is configured for connecting a first implant extension to a second implant extension. The transverse coupling includes a first sleeve, a second sleeve, and a central housing. The first sleeve defines a first aperture adapted to axially receive the first implant extension through the first aperture. The second sleeve defines a second aperture adapted to axially receive the second implant extension through the second aperture. A first shaft connects the first sleeve to the central housing, and a second shaft connects the second sleeve to the central housing.

The central housing includes a first joint and a second joint. In this arrangement, the first shaft connects the first sleeve to the first joint of the central housing, and the second shaft connects the second sleeve to the second joint of the central housing.

The first joint includes a universal ball joint that is pivotable with respect to the central housing.

The universal ball joint includes a longitudinal passage and a plurality of spring sections extending around the longitudinal passage.

In one beneficial embodiment of the present disclosure, the first shaft is axially displaceable through the longitudinal passage of the first joint.

In another beneficial embodiment of the present disclosure, the first shaft includes a first sleeve end attached to the first sleeve and a first free end opposite the first sleeve end, the first free end including a first stop to limit axial displacement of the first shaft through the longitudinal passage.

In another beneficial embodiment of the present disclosure, the first shaft is rotatable in the longitudinal passage of the first joint.

In another beneficial embodiment of the present disclosure, the first shaft includes a first shaft cross section with a first abutment face, and the longitudinal passage includes a passage cross section with a first abutment edge. The first abutment edge is configured to abut the first abutment face during rotation of the first shaft relative to the longitudinal passage and limit the range of rotation of the first shaft.

In another beneficial embodiment of the present disclosure, the second joint includes a cylindrical through-bore through the central housing.

In another beneficial embodiment of the present disclosure, the second shaft is axially displaceable through the through-bore of the second joint.

In another beneficial embodiment of the present disclosure, the second shaft includes a second sleeve end attached to the second sleeve and a second free end opposite the second sleeve end, the second free end including a second stop to limit axial displacement of the second shaft through the through-bore of the second joint.

In another beneficial embodiment of the present disclosure, the second shaft is rotatable in the through-bore of the second joint.

In another beneficial embodiment of the present disclosure, the second shaft includes a second shaft cross section with a second abutment face, and the through-bore includes a through-bore cross section with a second abutment edge, the second abutment edge configured to abut the second abutment face during rotation of the second shaft relative to the longitudinal passage and limit the range of rotation of the second shaft.

In another beneficial embodiment of the present disclosure, the central housing includes an upper portion, a lower portion separate from the upper portion, and an adjustment screw extending through the upper portion and the lower portion.

In another beneficial embodiment of the present disclosure, the upper portion and the lower portion of the central housing form an adjustable clamp that releasably secures the first shaft in the first joint and releasably secures the second shaft in the second joint.

In another beneficial embodiment of the present disclosure, the clamp is adjustable to a locked condition in response to rotation of the adjustment screw, wherein the upper portion and the lower portion of the central housing are drawn together in the locked condition to compress the first joint and the second joint and lock the positions of the first shaft and the second shaft relative to the central housing.

In another beneficial embodiment of the present disclosure, the clamp is adjustable to an unlocked condition in response to rotation of the adjustment screw, wherein the upper portion and the lower portion of the central housing are spread apart in the unlocked condition to permit the first shaft and the second shaft to move relative to the central housing.

In another beneficial embodiment of the present disclosure, the adjustment screw includes an outer thread and the lower portion of the central housing defines a bore with an inner thread, the outer thread mating with the inner thread.

In another beneficial embodiment peefr of the present disclosure, at least one of the first sleeve and the second sleeve defines a sleeve axis and a chamber.

In another beneficial embodiment of the present disclosure, at least one of the first sleeve and the second sleeve includes a locking ring defining a locking ring axis, the locking ring being translatable in the chamber in a direction transverse to the sleeve axis.

In another beneficial embodiment of the present disclosure, the locking ring is translatable relative to at least one of the first sleeve and the second sleeve between a locking position, in which the locking ring axis is offset from the sleeve axis by a first distance, and a release position, in which the locking ring axis is offset from the sleeve axis by a second distance, the first distance being greater than the second distance.

In another beneficial embodiment of the present disclosure, at least one of the first sleeve and the second sleeve includes a spring element in the chamber that exerts a biasing force on the locking ring to urge the locking ring toward the locking position.

In another beneficial embodiment of the present disclosure, the locking ring includes a projection extending radially inwardly into the aperture, the projection positioned in the aperture to releasably engage one of the first implant extension and the second implant extension when the locking ring is in the locking position.

In another beneficial embodiment of the present disclosure, the locking ring includes a release lug extending radially outwardly and away from the locking ring axis, and at least one of the first sleeve and the second sleeve defines a through-slot into which the release lug extends.

In another beneficial embodiment of the present disclosure, the release lug projects through the through-slot in an exposed position in which the release lug is depressible against the biasing force of the spring element to displace the locking ring toward the release position.

In another beneficial embodiment of the present disclosure, a transverse coupling is configured for connecting a first implant extension to a second implant extension. The transverse coupling includes a first sleeve, a second sleeve, and a central housing. The first sleeve defines a first aperture adapted to axially receive the first implant extension through the first aperture. The second sleeve defines a second aperture adapted to axially receive the second implant extension through the second aperture. A first shaft connects the first sleeve to the central housing, and a second shaft connects the second sleeve to the central housing. At least one of the first shaft and the second shaft is connected to the central housing by a movable joint on the central housing.

In another beneficial embodiment of the present disclosure, the transverse coupling includes a third sleeve defining a third aperture adapted to axially receive a third implant extension through the third aperture. The transverse coupling also includes a third shaft connecting the third sleeve to the central housing.

In another beneficial embodiment of the present disclosure, the transverse coupling includes a fourth sleeve defining a fourth aperture adapted to axially receive a fourth implant extension through the fourth aperture. The transverse coupling also includes a fourth shaft connecting the fourth sleeve to the central housing.

The summary and detailed description sections will be better appreciated when reviewed in conjunction with the drawing figures. The drawing figures illustrate exemplary and non-limiting embodiments of the invention, and depict elements which can be combined and arranged either as shown, or in any other combination and/or arrangement contemplated by persons having ordinary skill in the art.

Transverse couplers according to the present disclosure can be attached to two or more extensions mounted on pedicle screws as explained above. For example, a single transverse coupler can be attached to a pair of extensions attached to a vertebral body to maneuver the vertebral body in a procedure referred to as "single level derotation". Alternatively, a first transverse coupler can be attached to a first pair of extensions attached to a first vertebral body, and a second transverse coupler can be attached to a second pair of extensions attached to a second vertebral body. A first force can then be applied through the first transverse coupler to the first pair of extensions, and a second force can be applied simultaneously through the second transverse coupler to the second pair of extensions, to adjust the first and second vertebral bodies relative to one another in single level derotations. Furthermore, transverse couplers can be attached to a block of two or more vertebral bodies to adjust the block of vertebral bodes in an "en bloc" derotation.

Referring now to the drawings figures, and <FIG> specifically, a transverse coupling <NUM> is shown according to one example. Transverse coupling <NUM> is detachably mountable to a variety of different bone implants and extensions. As noted above, an extension can be part of the implant itself, or a separate component that is attached to the implant, such as a surgical instrument. In the present example, transverse coupling <NUM> will be described in combination with a first extension in the form of a first spinal rod persuader <NUM> and a second extension in the form of a second spinal rod persuader <NUM>'. First spinal rod persuader <NUM> is attached to a first pedicle screw <NUM>, and second spinal rod persuader <NUM>' is attached to a second pedicle screw <NUM>'.

First pedicle screw <NUM> is anchored in a first pedicle P of a vertebral body B through a first incision I. Similarly, second pedicle screw <NUM>' is anchored in a second pedicle P' of vertebral body B through a second incision I'. In this arrangement, transverse coupling <NUM> can receive an adjustment force F from a force applying instrument <NUM> and transfer the adjustment force through first and second spinal rod persuaders <NUM>, <NUM>' and first and second pedicle screws <NUM>, <NUM>' to vertebral body B. The transverse coupling <NUM>, rod persuader <NUM> and rod persuader <NUM>' collectively form a rigid construct. Adjustment forces can be applied directly to this construct or by other instruments attached to this construct. For example, transverse coupling <NUM> can receive an adjustment force by applying a force directly to one or both of rod persuaders <NUM>, <NUM>'. Alternatively, transverse coupling <NUM> can receive an adjustment force by applying force to an adjustment screw <NUM> on the traverse coupling. Force can be applied to adjustment screw <NUM> through a force applying instrument that attaches to a center knob <NUM> on the adjustment screw.

First and second pedicle screws <NUM>, <NUM>' are spaced apart and extend from their respective incisions I, I' at different trajectories. Consequently, first and second spinal rod persuaders <NUM>, <NUM>' are also spaced apart and extend from their respective incisions I, I' at different trajectories. The proximal ends of first and second spinal rod persuaders <NUM>, <NUM>' are separated by unique spacing S, and the different trajectories of first and second spinal rod persuaders define an angular offset α between their respective longitudinal axes X, X'. Transverse coupling <NUM> has a plurality of adjustable components to accommodate both spacing S and angular offset α between first and second rod persuaders <NUM>, <NUM>'. These adjustable components, which will be described in more detail, are movable relative to one another through one or more degrees of freedom to accommodate an infinite number of spacings and angular offsets between extensions.

Referring to <FIG>, transverse coupling <NUM> includes a central housing <NUM>, a first attachment assembly <NUM> and a second attachment assembly <NUM>. First attachment assembly <NUM> is detachably mountable to first spinal rod persuader <NUM>, and second attachment assembly <NUM> is detachably mountable to second spinal rod persuader <NUM>'. Central housing <NUM> interconnects first attachment assembly <NUM> and second attachment assembly <NUM> in an adjustable configuration that allows transverse coupling to adapt to different spacings and angular offsets between extensions.

First attachment assembly <NUM> includes a first sleeve <NUM> defining a first aperture <NUM>. First aperture <NUM> is adapted to axially receive first rod persuader <NUM> through the first aperture. Transverse coupling <NUM> also includes a second sleeve <NUM> defining a second aperture <NUM> adapted to axially receive second rod persuader <NUM>' through the second aperture. Central housing <NUM> includes an upper housing portion <NUM> and a lower housing portion <NUM>. Upper housing portion <NUM> and lower housing portion <NUM> are interconnected together in a clamping arrangement. In this clamping arrangement, upper housing portion <NUM> and lower housing portion <NUM> define a first joint <NUM> and a second joint <NUM>.

First attachment assembly <NUM> includes a first shaft <NUM> that extends outwardly and away from first sleeve <NUM>. First joint <NUM> slidably couples first shaft <NUM> to central housing <NUM>. In a similar arrangement, second attachment assembly <NUM> includes a second shaft <NUM> that extends outwardly and away from second sleeve <NUM>. Second joint <NUM> slidably couples second shaft <NUM> to central housing <NUM>.

First joint <NUM> comprises a universal ball joint <NUM> that is pivotable with respect to the central housing <NUM>. Ball joint <NUM> defines a longitudinal passage <NUM> that extends through the ball joint. Longitudinal passage <NUM> receives first shaft <NUM> of first attachment assembly <NUM> in a linear sliding relationship. This linear sliding relationship allows the first shaft <NUM> to be axially displaceable through longitudinal passage <NUM> along a first degree of freedom relative to central housing <NUM>. First shaft <NUM> is also axially rotatable relative to the longitudinal passage <NUM> in a second degree of freedom.

Ball joint <NUM> is sandwiched between upper housing portion <NUM> and lower housing portion <NUM> of central housing <NUM>. Upper housing portion <NUM> has a concave bearing surface <NUM> and lower housing portion <NUM> has a concave bearing surface <NUM> opposite concave bearing surface <NUM>. Ball joint <NUM> slidingly engages bearing surfaces <NUM>, <NUM> to pivot in place between upper and lower housing portions <NUM>, <NUM>. In this arrangement, ball joint <NUM> can pivot between upper and lower housing portions <NUM>, <NUM>. When first shaft <NUM> is received in longitudinal passage <NUM>, the first shaft can pivot through a third degree of freedom relative to central housing <NUM>, which is independent from the first and second degrees of freedom.

Upper and lower housing portions <NUM>, <NUM> form two halves of a clamp to control displacement of first shaft <NUM> in first joint <NUM>. In particular, upper and lower housing portions <NUM>, <NUM> can be clamped together to apply compression force on ball joint <NUM>. Longitudinal passage <NUM> has a first end <NUM> and a second end <NUM> opposite the first end. A first array of slots <NUM> intersect first end <NUM> of longitudinal passage <NUM>, and a second array of slots <NUM> intersect second end <NUM>. Slots <NUM>, <NUM> form flexible spring sections <NUM> that surround longitudinal passage <NUM>. Spring sections <NUM> are compressible under stored energy in a locked state. In the locked state, first shaft <NUM> cannot move or rotate axially through longitudinal passage <NUM>, and ball joint <NUM> cannot pivot between upper and lower housing portions <NUM>, <NUM>. When some of the compression force on ball joint <NUM> is removed, stored energy in spring sections <NUM> is released, causing the spring sections to expand radially outwardly. As spring sections <NUM> expand outwardly, they move toward a relaxed state, in which at least some clamping force on first shaft is removed. This removal of clamping force allows first shaft <NUM> to move axially through longitudinal passage <NUM>. Removal of compression force on ball joint <NUM> also allows the ball joint to once again pivot between upper and lower housing portions <NUM>, <NUM> of central housing <NUM>.

First shaft <NUM> has a first sleeve end <NUM> attached to first sleeve <NUM>. First shaft <NUM> also has a first free end <NUM> opposite first sleeve end <NUM>. First free end <NUM> includes a first stop <NUM> to limit axial displacement of first shaft <NUM> through longitudinal passage <NUM>.

First shaft <NUM> defines a first shaft axis <NUM> that is parallel to a longitudinal axis of longitudinal passage <NUM>. When first shaft <NUM> is not clamped in ball joint <NUM>, the first shaft is rotatable about its longitudinal axis <NUM> in longitudinal passage <NUM> in the second degree of freedom.

Second joint <NUM> comprises a cylindrical through-bore <NUM> defined between upper housing portion <NUM> and lower housing portion <NUM>. Upper housing portion <NUM> forms a concave channel surface <NUM> and lower housing portion <NUM> forms a concave channel surface <NUM>. Concave channel surfaces <NUM>, <NUM> form two halves of through-bore <NUM> and form the through-bore when upper and lower housing portions <NUM>, <NUM> are connected together. Second shaft <NUM> is axially displaceable through through-bore <NUM> of second joint <NUM> in a first degree of freedom, similar to first shaft <NUM> in longitudinal passage <NUM>. In addition, second shaft <NUM> defines a second shaft axis <NUM> that is parallel to a longitudinal axis of through-bore <NUM>. As such, second shaft <NUM> is rotatable about second shaft axis <NUM> in through-bore in a second degree of freedom.

Second shaft <NUM> has a second sleeve end <NUM> attached to the second sleeve <NUM> and a second free end <NUM> opposite the second sleeve end. Second free end <NUM> includes a second stop <NUM> to limit axial displacement of second shaft <NUM> through the through-bore <NUM> of second joint <NUM>.

Shafts according to the present disclosure can rotate the full <NUM> degrees about their longitudinal axis if desired to adjust the orientation of first their respective sleeves. A full <NUM> degree rotation is not necessary in many applications, however, because sleeves do not need to be rotated through a large range. Therefore, attachment assemblies according to the present disclosure can feature rotation limiters to limit the range of axial rotation of the shafts.

Referring now to <FIG>, one example of a rotation limiter is shown between second shaft <NUM> and through-bore <NUM>. Second shaft <NUM> has a truncated cylindrical shape that defines a first cylindrical face <NUM> and a first abutment face <NUM>. First cylindrical face <NUM> and first abutment face <NUM> form a shaft cross section <NUM> in the shape of a truncated circle or "D shape". Through-bore <NUM> has a similar D-shaped cross section <NUM> with a first cylindrical edge <NUM> and a first abutment edge <NUM>. First abutment face <NUM> is configured to abut first abutment edge <NUM> during rotation of second shaft <NUM> relative to through-bore <NUM>. When first abutment face <NUM> abuts first abutment edge <NUM>, the first abutment edge prevents second shaft <NUM> from rotating any further in that direction of rotation.

First abutment face <NUM> can abut first abutment edge <NUM> in two relative orientations shown in <FIG>. The orientations in <FIG>, which are <NUM> degrees apart, represent the limits of axial rotation of second shaft <NUM>. Although not shown, it will be appreciated that first shaft <NUM> and longitudinal passage <NUM> can have an identical or similar abutment face and abutment edge, respectively, that limit relative rotation of the first shaft through a range of <NUM> degrees. It will also be appreciated that rotation limiters according to the present disclosure can also be configured to permit smaller or larger ranges of axial rotation, and need not limit rotation to <NUM> degrees.

Sleeves and shafts according to the present disclosure can be interconnected with fixed joints that fix the orientation of the sleeve relative to the shaft. Alternatively, sleeves and shafts according to the present disclosure can be interconnected with one or movable joints that allow the sleeve to articulate relative to the shaft in one or more degrees of freedom. A movable joint allows a sleeve to be tilted or pivoted in one or more planes relative to its respective shaft to more easily adapt the locking ring aperture to the position and angulation of an extension. In the present example, first sleeve <NUM> is connected to sleeve end <NUM> of first shaft <NUM> with a pin connection <NUM>. Second sleeve <NUM> is connected to sleeve end <NUM> of second shaft <NUM> by a clevis joint <NUM>, which in turn is connected to the second sleeve with a pin connection <NUM>. Sleeve end <NUM> of first shaft <NUM> also has a bend <NUM> that provides a fixed angular offset between free end <NUM> of the first shaft and first sleeve <NUM>.

Upper housing portion <NUM> and lower housing portion <NUM> are interconnected by a fastener that holds the upper housing portion and lower housing portion together in a clamping arrangement. Transverse couplings according to the present disclosure can utilize a variety of fasteners to interconnect the upper and lower housing portions in a clamping arrangement, including but not limited to threaded bolts, cam bolts, and other connectors suitable for drawing the upper and lower housing portions together and spreading them apart. In the present example, upper and lower housing portions <NUM>, <NUM> are interconnected by an adjustment screw <NUM>, seen best in <FIG>. Adjustable screw <NUM> extends through an upper bore <NUM> that extends through upper housing <NUM>. Upper bore <NUM> axially aligns with a lower bore <NUM> in lower housing portion <NUM> when the upper and lower housing portions are assembled. Lower bore <NUM> has an inner thread <NUM> that mates with an outer thread <NUM> on adjustment screw <NUM>. In this arrangement, adjustment screw <NUM> is freely insertible in an axial direction through upper bore <NUM> and into lower bore <NUM> until outer thread <NUM> engages inner thread <NUM> in the lower bore. Adjustment screw <NUM> can then be rotated to engage outer thread <NUM> with inner thread <NUM> and axially advance the adjustment screw into lower bore.

With reference to the top view shown in <FIG>, adjustment screw <NUM> can be rotated in a clockwise direction to draw upper and lower housing portions <NUM>, <NUM> together and into a clamping state. In the clamping state, the first and second shafts <NUM>, <NUM> completely fixed against all movement relative to central housing <NUM>. That is, the upper and lower housing portions <NUM>, <NUM> are drawn together such that first shaft <NUM> is frictionally locked in ball joint <NUM> and cannot move axially or rotate in any direction relative to the ball joint. In addition, ball joint <NUM> is compressed by upper and lower housing portions <NUM>, <NUM> such that the ball joint is frictionally locked between concave bearing surfaces <NUM>, <NUM> and cannot pivot in any direction between the upper and lower housing portions. Moreover, second shaft <NUM> is frictionally locked between concave channel surface <NUM> and concave channel surface <NUM> so that it cannot move axially or rotate in any direction relative to central housing <NUM>.

Adjustment screw <NUM> can also be rotated in a counter-clockwise direction to loosen the connection between upper and lower housing portions <NUM>, <NUM> so that the upper and lower housing portions are in a release state. In the release state, upper and lower housing portions <NUM>, <NUM> have more freedom to spread apart such that the friction forces on ball joint <NUM>, first shaft <NUM> and second shaft <NUM> are minimal and be overcome by applying manual forces on the shafts to move them relative to central housing <NUM>.

Transverse couplings according to the present disclosure preferably include one or more components to prevent the upper housing portion from toggling or moving loosely relative to the lower housing portion and adjustment screw when the upper and lower housings are not in the clamping state. In the present example, a wave spring <NUM> is inserted between adjustment screw <NUM> and upper housing portion <NUM>. Wave spring <NUM> is compressed between adjustment screw <NUM> and upper housing portion <NUM> under stored energy. The stored energy in wave spring <NUM> applies a constant pressure on upper housing portion <NUM> in the direction of lower housing portion <NUM> to maintain the upper housing portion in constant contact with first shaft <NUM> and second shaft <NUM>. This constant contact prevents upper housing portion <NUM> from toggling, flopping or otherwise moving in a loose manner around adjustment screw <NUM>, even when the adjustment screw is loosened and the upper and lower housings are in the release state.

Transverse couplings according to the present disclosure can also have various components for securing the assembly and preventing disassembly of components. In the present example, a nut <NUM> is attached to the narrow end of adjustment screw <NUM> to prevent disassembly of the upper housing portion <NUM> and lower housing portion <NUM> from the other components. Nut <NUM>, which is shown in <FIG> and <FIG>, is attached to the narrow end of adjustment screw <NUM> by welding. It will be understood that various types of fasteners can be used to prevent disassembly. These fasteners can be connected to the adjustment screw by welding, a threaded connection, locking pins or various other types of connection.

Referring now to <FIG>, the first and second sleeves <NUM>, <NUM> will be described in more detail. Sleeves <NUM>, <NUM> are designed to be slipped over a pair of extensions and locked to those extensions to interconnect the extensions together as a unit. Sleeves according to the present disclosure can have one or more design features to accommodate different types of extensions, different types of locking mechanisms or other design variables. In the present example, first and second sleeves <NUM>, <NUM> are identical, and many of the same components are visible in the drawing figures in both sleeves. Therefore, only features of sleeve <NUM> will be described, with the understanding that the same features are present in sleeve <NUM>.

First sleeve <NUM> includes a hollowing housing <NUM> having an upper housing section <NUM> and a lower housing section <NUM>. Upper and lower housing sections <NUM>, <NUM> are connected together to define a hollow chamber <NUM> between the housing sections. Hollow chamber <NUM> is substantially enclosed around the perimeter of first sleeve <NUM> but is open toward first aperture <NUM>. First aperture <NUM> has a perimeter that conforms to a circle and defines a sleeve axis <NUM> that passes through the center of the circle.

First sleeve <NUM> has a floating locking ring <NUM> housed inside chamber <NUM>. Locking ring <NUM> is translatable inside chamber <NUM> between a locking position to lock first sleeve <NUM> to an extension, and a release position to allow the first sleeve to slide up and down the extension. Locking ring <NUM> defines an opening <NUM> having a perimeter that conforms to a circle and a locking ring axis <NUM> that passes through the center of the circle. Locking ring axis <NUM> is parallel to sleeve axis <NUM>.

Locking ring <NUM> is translatable in chamber <NUM> in a direction transverse to sleeve axis <NUM>. In the locking position, locking ring axis <NUM> is offset from sleeve axis <NUM> by a first distance D1, shown in <FIG>. In the release position, locking ring axis <NUM> is offset from sleeve axis <NUM> by a second distance D2, shown in <FIG>. When locking ring <NUM> is moved to the locking position, opening <NUM> is less aligned with first aperture <NUM>. When locking ring <NUM> is moved to the release position, opening <NUM> is moved inwardly toward central housing <NUM>, such that the opening is more aligned with first aperture <NUM>. In other words, first distance D1 associated with the locking position is greater than second distance D2 associated with the release position. If desired, locking ring <NUM> can be arranged in first sleeve <NUM> in such a way that locking ring axis <NUM> aligns coaxially with sleeve axis <NUM> when the locking ring is moved to the release position, in which case second distance D2 would be zero. Locking ring <NUM> can also be arranged in first sleeve <NUM> in such a way that locking ring axis <NUM> moves past sleeve axis <NUM> to be positioned closer to central housing <NUM> than the sleeve axis, in which case D2 would be a negative value. Any of these arrangements is suitable so long as the movement of locking ring <NUM> to the release position moves the projection away from sleeve axis <NUM> and toward central housing <NUM>.

First sleeve <NUM> includes a spring element <NUM> in chamber <NUM>. Spring element <NUM> is held in a compressed state between locking ring <NUM> and an inner wall <NUM> of chamber <NUM>. In this arrangement, spring element <NUM> exerts a biasing force directed radially inwardly toward sleeve axis <NUM> to urge the locking ring toward the locking position. Sleeves according to the present disclosure can include a variety of spring elements that exert a biasing force on the locking ring, including but not limited to coil springs, disc springs and leaf springs. In the present example, spring element <NUM> is a wave spring. Locking ring <NUM> includes a projection <NUM> extending radially inwardly into opening <NUM>. Projection <NUM> is positioned to releasably engage a locking feature, such as a locking recess or detent, on an extension when the projection is in the locking position. Projection <NUM> has leading edge <NUM>, a trailing edge <NUM> and a sliding edge 337between the leading edge and trailing edge. Each of edges <NUM>, <NUM> and <NUM> plays a role in locking and unlocking first sleeve <NUM> from an extension. Leading edge <NUM> is designed to contact the top edge of an extension when first sleeve <NUM> is initially placed over the top of an extension. During initial placement, locking ring <NUM> is urged to the locking position by spring element <NUM>, with projection <NUM> protruding into first aperture <NUM>. Leading edge <NUM> has a chamfered face <NUM> that abuts the top edge of the extension as first sleeve <NUM> is lowered onto the extension. The orientation of chamfered face <NUM> and the floating arrangement of locking ring <NUM> cause the locking ring to be deflected against the biasing force of spring element <NUM> and toward central housing <NUM> as first sleeve <NUM> is advanced down the extension. This causes projection <NUM> to temporarily move out of the locking position to the unlocking position. Locking ring <NUM> is deflected until sliding edge <NUM> contacts the outer geometry of the extension. <FIG> shows first sleeve <NUM> and locking ring <NUM> being advanced down an extension E, with sliding edge <NUM> abutting the exterior of the extension.

First sleeve <NUM> can be advanced downwardly around the outer geometry of an extension until the outer geometry of the extension prevent the first sleeve from being advanced any further. For example, the outer geometry of the extension may have a widened section that cannot fit through opening <NUM> in locking ring <NUM>. The widened section can therefore stabilize first sleeve <NUM> from moving any further down extension. Extension can further include a cutout or window positioned to engage projection <NUM> to prevent first sleeve <NUM> from being inadvertently reversed or moved back up the extension. In such a design, first sleeve <NUM> is advanced downwardly on the extension until locking ring <NUM> engages the widened geometry, at which point projection <NUM> aligns with the cutout or window. The dimensions of the cutout or window are the same as or slightly larger than the dimensions of projection <NUM>, such that the projection can snap into the cutout or window as stored energy in spring element <NUM> is released. Once projection <NUM> enters the cutout or window, trailing edge <NUM> abuts the upper edge of the window, preventing locking ring <NUM> and first sleeve <NUM> from moving back up the extension. <FIG> shows first sleeve <NUM> and locking ring <NUM> further advanced down extension E, with projection <NUM> snapped inwardly into a window W, and with trailing edge <NUM> abutting a top edge of the window to prevent the first sleeve from being reversed and moved up the extension.

Sleeves according to the present disclosure can have one or more release mechanisms to move the locking ring out of the locking position and permit the sleeve to be removed from an extension. In the present example, locking ring <NUM> includes a release lug <NUM> that extends radially outwardly and away from locking ring axis <NUM>. Sleeve housing <NUM> defines a through-slot <NUM> into which release lug <NUM> extends. Release lug <NUM> projects out of through-slot <NUM> in an exposed position on the exterior of first sleeve <NUM>. In this exposed position, release lug <NUM> is depressible against the biasing force of spring element <NUM> to displace locking ring <NUM> toward the release position. This moves projection <NUM> out of the window or cutout in the extension so that first sleeve <NUM> is no longer prevented from being lifted and removed from the extension. To remove first sleeve <NUM> from an extension, a user can depress and hold release lug <NUM> inwardly toward sleeve axis <NUM>, and lift first sleeve until projection <NUM> is above the window or cutout. Once projection <NUM> is above the window or cutout, the user can continue to depress release lug <NUM> as first sleeve <NUM> is lifted off the extension. Alternatively, the user can release the release lug <NUM>, at which time sliding edge <NUM> will abut the exterior of the extension and slide along the outer geometry of the extension until first sleeve <NUM> is removed.

Although the present disclosure pertains to specific embodiments, the present disclosure is not intended to be limited to the details shown. Rather, various modifications, combinations, substitutions and/or rearrangements can be made with respect to the components and their features shown herein, with any such modification, combination, substitution and/or rearrangement being contemplated within the scope and range of equivalents of the claims and without departing from the present disclosure.

For example, transverse couplings according to the present disclosure can feature a single pair of sleeves with associated shafts interconnected by a central housing, as shown with transverse coupling <NUM> in <FIG> and <FIG>. Alternatively, transverse couplings according to the present disclosure can feature two or more pairs of sleeves with associated shafts interconnected by central housings. Embodiments with two or more pairs of sleeves with associated shafts and central housings could appear as multiple transverse couplings <NUM> attached together in parallel. In a parallel arrangement, transverse coupling <NUM> shown in <FIG> could be attached to a second transverse coupling that would appear above it in the Figure, and attached to a third transverse coupling beneath it in the Figure. The three transverse couplings could be interconnected to one another by a connector that interconnects the adjustment screws or other parts of the transverse couplings.

Transverse couplings according to the present disclosure can also feature a single central housing as shown in <FIG>, but with three or more attachment assemblies connected to the central housing.

For example, <FIG> and <FIG> show a transverse coupling <NUM> with a first attachment assembly <NUM> (having a first sleeve <NUM> and first shaft <NUM>), a second attachment assembly <NUM> (having a second sleeve <NUM> and second shaft <NUM>) and a third attachment assembly <NUM> (having a third sleeve <NUM> and third shaft <NUM>) all connected to a central housing <NUM>. First, second and third attachment assemblies <NUM>, <NUM> and <NUM> are arranged around central housing <NUM> to connect the central housing to three different implants or extensions.

<FIG> and <FIG> show another transverse coupling <NUM>' with a first attachment assembly <NUM>' (having a first sleeve <NUM>' and first shaft <NUM>'), a second attachment assembly <NUM>' (having a second sleeve <NUM>' and second shaft <NUM>'), a third attachment assembly <NUM>' (having a third sleeve <NUM>' and third shaft <NUM>'), and a fourth attachment assembly <NUM>' (having a fourth sleeve <NUM>' and fourth shaft <NUM>') all connected to a central housing <NUM>'. First, second, third and fourth attachment assemblies <NUM>', <NUM>', <NUM>' and <NUM>' are arranged around central housing <NUM>' to connect the central housing to four different implants or extensions.

It will be appreciated that embodiments according to the present disclosure can include five or more attachment assemblies attached to a single central housing. Moreover, it will be appreciated that embodiments according to the present disclosure can have one or more attachment assemblies that are detachably connected to the central housing. Attachment assemblies that are detachable from the central housing permit the transverse coupler to be modified and adapted to the number of implants or extensions that require coupling to a single housing.

The present invention according to the first embodiment refers to a surgical instrumentation for vertebral derotation with a first implant extension (<NUM>), a second implant extension (<NUM>') and a transverse coupling <NUM>; <NUM>; <NUM>' for connecting the first implant extension <NUM> to the second implant extension <NUM>', the first implant extension (<NUM>) being configured to be attached to a first pedicle screw (<NUM>), the second implant extension (<NUM>') being configured to be attached to a second pedicle screw (<NUM>') and the transverse coupling <NUM>; <NUM>; <NUM>' comprising: a first sleeve <NUM>; <NUM>; <NUM>' defining a first aperture <NUM> adapted to axially receive the first implant extension <NUM> through the first aperture <NUM>; a second sleeve <NUM>; <NUM>; <NUM>' defining a second aperture <NUM> adapted to axially receive the second implant extension <NUM>' through the second aperture <NUM>; a central housing <NUM>; <NUM>; <NUM>' comprising a first joint <NUM> and a second joint <NUM>; a first shaft <NUM>; <NUM>; <NUM>' connecting the first sleeve <NUM>; <NUM>; <NUM>' to the first joint <NUM> of the central housing <NUM>; <NUM>; <NUM>' and a second shaft <NUM>; <NUM>; <NUM>' connecting the second sleeve <NUM>; <NUM>; <NUM>' to the second joint <NUM> of the central housing <NUM>; <NUM>; <NUM>'.

The first joint <NUM> comprises a universal ball joint <NUM> that is pivotable with respect to the central housing <NUM>; <NUM>; <NUM>'.

The universal ball joint <NUM> comprises a longitudinal passage <NUM> and a plurality of spring sections <NUM> extending around the longitudinal passage <NUM>.

According to a second embodiment of the invention, the transverse coupling <NUM>; <NUM>; <NUM>' according to the first embodiment is further characterized in that the first shaft <NUM>; <NUM>; <NUM>' is axially displaceable through the longitudinal passage <NUM> of the first joint <NUM>.

According to a third embodiment of the invention, the transverse coupling <NUM>; <NUM>; <NUM>' according to the first embodiment is further characterized in that the first shaft <NUM>; <NUM>; <NUM>' comprises a first sleeve end <NUM> attached to the first sleeve <NUM>; <NUM>; <NUM>' and a first free end <NUM> opposite the first sleeve end <NUM>, the first free end <NUM> comprising a first stop <NUM> to limit axial displacement of the first shaft <NUM>; <NUM>; <NUM>' through the longitudinal passage <NUM>, and/or in that the first shaft <NUM>; <NUM>; <NUM>' is rotatable in the longitudinal passage <NUM> of the first joint <NUM> and/or in that the first shaft <NUM>; <NUM>; <NUM>' comprises a first shaft cross section with a first abutment face <NUM>, and the longitudinal passage <NUM> comprises a passage cross section with a first abutment edge <NUM>, the first abutment edge <NUM> configured to abut the first abutment face <NUM> during rotation of the first shaft <NUM>; <NUM>; <NUM>' relative to the longitudinal passage <NUM> and limit the range of rotation of the first shaft <NUM>; <NUM>; <NUM>'.

According to fourth embodiment of the invention, the transverse coupling <NUM>; <NUM>; <NUM>' according to one of the previous embodiments is further characterized in that the second joint <NUM> comprises a cylindrical through-bore <NUM> through the central housing <NUM>; <NUM>; <NUM>'.

According to a fifth embodiment of the invention, the transverse coupling <NUM>; <NUM>; <NUM>' according to the fourth embodiment is further characterized in that the second shaft <NUM>; <NUM>; <NUM>' is axially displaceable through the through-bore <NUM> of the second joint <NUM>, and/or in that the second shaft <NUM>; <NUM>; <NUM>' comprises a second sleeve end <NUM> attached to the second sleeve <NUM>; <NUM>; <NUM>' and a second free end <NUM> opposite the second sleeve end <NUM>, the second free end <NUM> comprising a second stop <NUM> to limit axial displacement of the second shaft <NUM>; <NUM>; <NUM>' through the through-bore <NUM> of the second joint <NUM>. and/or in that the second shaft <NUM>; <NUM>; <NUM>' is rotatable in the through-bore <NUM> of the second joint <NUM> and/or in that the second shaft <NUM>; <NUM>; <NUM>' comprises a second shaft cross section with a second abutment face, and the through-bore <NUM> comprises a through-bore cross section with a second abutment edge, the second abutment edge configured to abut the second abutment face during rotation of the second shaft <NUM>; <NUM>; <NUM>' relative to the longitudinal passage <NUM> and limit the range of rotation of the second shaft <NUM>; <NUM>; <NUM>'.

According to a sixth embodiment of the invention, the transverse coupling <NUM>; <NUM>; <NUM>' according to one of the previous embodiments is further characterized in that the central housing <NUM>; <NUM>; <NUM>' comprises an upper portion <NUM>, a lower portion <NUM> separate from the upper portion <NUM>, and an adjustment screw <NUM> extending through the upper portion <NUM> and the lower portion <NUM>.

According to a seventh embodiment of the invention, the transverse coupling <NUM>; <NUM>; <NUM>' according to the sixth embodiment is further characterized in that the upper portion <NUM> and the lower portion <NUM> of the central housing <NUM>; <NUM>; <NUM>' form an adjustable clamp that releasably secures the first shaft <NUM>; <NUM>; <NUM>' in the first joint <NUM> and releasably secures the second shaft <NUM>; <NUM>; <NUM>' in the second joint <NUM>, and/or in that the adjustment screw <NUM> comprises an outer thread <NUM> and the lower portion <NUM> of the central housing <NUM>; <NUM>; <NUM>' defines a bore <NUM> with an inner thread <NUM>, the outer thread <NUM> mating with the inner thread <NUM>.

According to an eighth embodiment of the invention, the transverse coupling <NUM>; <NUM>; <NUM>' according to the seventh embodiment peet is further characterized in that the clamp is adjustable to a locked condition in response to rotation of the adjustment screw <NUM>, wherein the upper portion <NUM> and the lower portion <NUM> of the central housing <NUM>; <NUM>; <NUM>' are drawn together in said locked condition to compress the first joint <NUM> and the second joint <NUM> and lock the positions of the first shaft <NUM>; <NUM>; <NUM>' and the second shaft <NUM>; <NUM>; <NUM>' relative to the central housing <NUM>; <NUM>; <NUM>', and/or in that the clamp is adjustable to an unlocked condition in response to rotation of the adjustment screw <NUM>, wherein the upper portion <NUM> and the lower portion <NUM> of the central housing <NUM>; <NUM>; <NUM>' are spread apart in said unlocked condition to permit the first shaft <NUM>; <NUM>; <NUM>' and the second shaft <NUM>; <NUM>; <NUM>' to move relative to the central housing <NUM>; <NUM>; <NUM>'.

According to a ninth embodiment peefr of the invention, the transverse coupling <NUM>; <NUM>; <NUM>' according to one of the previous embodiments is further characterized in that at least one of the first sleeve <NUM>; <NUM>; <NUM>' and the second sleeve <NUM>; <NUM>; <NUM>' defines a sleeve axis <NUM> and a chamber <NUM>.

According to a tenth embodiment peefr of the invention, the transverse coupling <NUM>; <NUM>; <NUM>' according to the ninth embodiment is further characterized in that said at least one of the first sleeve <NUM>; <NUM>; <NUM>' and the second sleeve <NUM>; <NUM>; <NUM>' comprises a locking ring <NUM> defining a locking ring axis <NUM>, the locking ring <NUM> being translatable in the chamber <NUM> in a direction transverse to the sleeve axis <NUM>.

According to a eleventh embodiment of the invention, the transverse coupling <NUM>; <NUM>; <NUM>' according to the tenth embodiment is further characterized in that the locking ring <NUM> is translatable relative to said at least one of the first sleeve <NUM>; <NUM>; <NUM>' and the second sleeve <NUM>; <NUM>; <NUM>' between a locking position, in which the locking ring axis <NUM> is offset from the sleeve axis <NUM> by a first distance D<NUM>, and a release position, in which the locking ring axis <NUM> is offset from the sleeve axis <NUM> by a second distance D<NUM>, the first distance D<NUM> being greater than the second distance D<NUM>, and/or in that said at least one of the first sleeve <NUM>; <NUM>; <NUM>' and the second sleeve <NUM>; <NUM>; <NUM>' comprises a spring element <NUM> in the chamber <NUM> that exerts a biasing force on the locking ring <NUM> to urge the locking ring <NUM> toward the locking position, and/or in that the locking ring <NUM> comprises a projection <NUM> extending radially inwardly into the aperture <NUM> the projection <NUM> positioned in the aperture <NUM> to releasably engage one of the first implant extension <NUM> and the second implant extension <NUM>' when the locking ring <NUM> is in the locking position, and/or in that the locking ring <NUM> comprises a release lug <NUM> extending radially outwardly and away from the locking ring axis <NUM>, said at least one of the first sleeve <NUM>; <NUM>; <NUM>' and the second sleeve <NUM>; <NUM>; <NUM>' defining a through-slot <NUM> into which the release lug <NUM> extends, wherein the release lug <NUM> preferably projects through the through-slot <NUM> in an exposed position in which the release lug <NUM> is depressible against the biasing force of the spring element <NUM> to displace the locking ring <NUM> toward the release position.

Claim 1:
A surgical instrumentation for vertebral derotation with a first implant extension (<NUM>), a second implant extension (<NUM>') and a transverse coupling (<NUM>; <NUM>; <NUM>') for connecting the first implant extension (<NUM>) to the second implant extension (<NUM>'), the first implant extension (<NUM>) being configured to be attached to a first pedicle screw (<NUM>), the second implant extension (<NUM>') being configured to be attached to a second pedicle screw (<NUM>') and the transverse coupling comprising:
a first sleeve (<NUM>; <NUM>; <NUM>') defining a first aperture (<NUM>) adapted to axially receive the first implant extension (<NUM>) through the first aperture (<NUM>);
a second sleeve (<NUM>; <NUM>; <NUM>') defining a second aperture (<NUM>) adapted to axially receive the second implant extension (<NUM>') through the second aperture (<NUM>);
a central housing (<NUM>; <NUM>; <NUM>');
a first shaft (<NUM>; <NUM>; <NUM>') connecting the first sleeve (<NUM>; <NUM>; <NUM>') to the central housing (<NUM>; <NUM>; <NUM>'); and
a second shaft (<NUM>; <NUM>; <NUM>') connecting the second sleeve (<NUM>; <NUM>; <NUM>') to the central housing (<NUM>; <NUM>; <NUM>'),
at least one of the first shaft (<NUM>; <NUM>; <NUM>') and the second shaft (<NUM>; <NUM>; <NUM>') being connected to the central housing (<NUM>; <NUM>; <NUM>') by a movable joint (<NUM>, <NUM>) on the central housing (<NUM>; <NUM>; <NUM>'), wherein
the central housing (<NUM>; <NUM>; <NUM>') comprises a first joint (<NUM>) and a second joint (<NUM>);
the first shaft (<NUM>; <NUM>; <NUM>') connects the first sleeve (<NUM>; <NUM>; <NUM>') to the first joint (<NUM>) of the central housing (<NUM>; <NUM>; <NUM>');
the second shaft (<NUM>; <NUM>; <NUM>') connects the second sleeve (<NUM>; <NUM>; <NUM>') to the second joint (<NUM>) of the central housing (<NUM>; <NUM>; <NUM>'); and
the first joint (<NUM>) comprises a universal ball joint (<NUM>) that is pivotable with respect to the central housing (<NUM>; <NUM>; <NUM>'),
characterized in that
the universal ball joint (<NUM>) comprises a longitudinal passage (<NUM>) and a plurality of spring sections (<NUM>) extending around the longitudinal passage (<NUM>).