Patent Description:
Many types of spinal irregularities can cause pain, limit range of motion, or injure the nervous system within the spinal column. These irregularities can result from, without limitation, trauma, tumor, disc degeneration, and disease. Often, these irregularities are treated through a surgical procedure that may include, for example, immobilizing a portion of the spine. These treatments may involve, for example, replacing a damaged disc with an intervertebral implant and/or securing the adjacent vertebrae, for example, with a combination of screws and rods. For correction of a collapsed disc causing impingement of one or more nerve roots, for example, the disc space may be restored back to or near its original height and the collapsed disc may be replaced with a device and/or bone graft material.

In order to perform these procedures, a surgical opening is created, and a device such as a retractor may be used to enlarge the opening and facilitate access to the surgical site. The retractor may typically include one or more blades that can be adjusted to establish, provide, and/or maintain an appropriate opening that minimizes trauma to surrounding tissue. A distractor may also be used to distract the disc space, for example, by placing a portion of the distractor between vertebral bodies or by using adjacent level pedicle screws.

By using a pedicle-based retraction system, the retractor can perform the functions of both a retractor and a distractor. For example, the blades may provide for soft tissue retraction, and the pedicle screws may be configured to simultaneously facilitate distraction of the disc space.

<CIT> and <CIT> describe retractor blade assemblies known in the art.

There is a need, however, for improved retractors which provide pedicle-based distraction and soft tissue retraction. For example, pedicle-based retractors require a secure connection between the blade and the pedicle screw. It is also desirable to have a mechanism to attach the blades to the screws after the screws have already been affixed to bone. Preferably, there is a minimal amount of tissue disruption when connecting the blades to the screws intra-operatively.

To meet this and other needs, devices, systems for performing pedicle-based surgical retraction are provided. The invention is defined by a retractor blade assembly according to the independent claim <NUM>. Further advantageous aspects of the invention are set forth in the dependent claims.

In particular, the pedicle-based retractors are provided with specially designed connections between the pedicle screw and blade, which create a secure reversible connection between the pedicle screw and the retractor blade. After the screw is implanted in the bone, the blade may be attached to the screw in a manner to minimize the amount of tissue disruption at the surgical site.

It is described a retractor blade assembly that includes a retractor blade, a screw, and a shim which connects the screw to the retractor blade. The retractor blade may have a proximal end configured to engage a retractor body and a distal end configured to retract soft tissue. The screw may have a head portion removably connectable to the distal end of the retractor blade and a shaft portion configured to engage bone. The shim may have an extension portion configured to engage the retractor blade and a connection portion configured to receive at least a portion of the screw. The connection portion may be movable from an unlocked position to a locked position for retaining the screw within the shim.

It is further described, a retractor assembly that includes a retractor body, at least one retractor blade, at least one pedicle screw, and at least one shim that connects the pedicle screw to the retractor blade. The retractor blade may have a proximal end configured to engage the retractor body and a distal end configured to retract soft tissue. The pedicle screw may have a head portion removably connectable to the distal end of the retractor blade and a shaft portion configured to engage bone. The shim may have an extension portion, an outer spherical portion, and an inner spherical portion rotatably received within the outer spherical portion. The extension portion may be configured to engage the retractor blade and the inner spherical portion may be configured to receive the head portion of the pedicle screw. The inner spherical portion rotates from an unlocked position to a locked position for retaining the head portion of the pedicle screw within the shim.

The retractor blade assembly and/or the retractor assembly may include one or more of the following attributes: the extension portion may include at least one rail configured to slidably engage at least one corresponding rail on the retractor blade; the extension portion may include at least one edge configured to surround one or both end portions of the retractor blade; the retractor blade may include a generally curved inner portion having one or more grooves defined along at least a portion of the at least one retractor blade, the one or more grooves configured to slidably engage one or more corresponding tongues of the extension portion of the at least one shim; the shim may include an elongated slot extending longitudinally along a length of the shim; the connection portion may be configured to rotate relative to the retractor blade; the connection portion may include at least a partial ring configured to at least partially surround the head portion of the screw; a top portion of the inner spherical portion may extend through an opening in the outer spherical portion, and the top portion may be configured to be engaged by a driver in order to rotate the inner spherical portion from the unlocked position to the locked position; the screw may be side-loaded into the shim; the outer spherical portion and the inner spherical portion may each include an opening that, when aligned, allow the pedicle screw to be side-loaded into the shim; the pedicle screw may be configured to polyaxially rotate in the shim; one or more locks may be positioned along one or both outer edges of the retractor blade to prevent the shim from sliding off the retractor blade; and the driver may include at least one track configured to engage the at least one rail on the extension portion of the shim.

According to another embodiment, a retractor blade assembly includes a pedicle screw, a retractor blade and a screw mount. The pedicle screw has a head portion and a shaft portion configured to engage bone. The retractor blade has a proximal end and a distal end configured to retract soft tissue. The screw mount has an extension portion defining at least one blade mounting assembly and a head portion defining a screw head receiving chamber. The chamber is defined by a concave interior wall of the head portion and a moveable retaining member extending from the extension portion with a free end of the retaining member extending within the head portion and defining a concave surface opposed to the concave interior wall.

According to yet another embodiment, a retractor blade assembly includes a pedicle screw, a tulip screw mount and a retractor blade. The pedicle screw has a head portion and a shaft portion configured to engage bone. The tulip screw mount includes a tulip with a closed end defining a screw head seat and extension legs extending proximally from the tulip with a slot extending therebetween. The retractor blade has a body extending between a proximal end and a distal end configured to retract soft tissue, the retractor blade body defining a rail configured to be received in the screw mount slot to retain the retractor blade on the tulip screw mount.

According to another embodiment, a method of connecting a retractor blade to a pedicle is provided. The method includes connecting a driver to a screw mount. The screw mount includes an extension portion and a head portion, the head portion having a concave internal wall and the extension portion including a moveable retaining member with a free end that extends into the head portion such that a concave surface of the retaining member is opposed to the concave internal wall to define a screw head chamber. The method further includes positioning the head of a pedicle screw within the chamber and moving a locking mechanism to a locking position wherein a portion of the locking mechanism engages the retaining member and prevents the retaining member from moving radially outwardly. The pedicle screw is attached to a pedicle of a vertebra and a retractor blade, having a proximal portion and a distal portion, is slid down the driver and onto the screw mount such that the distal portion of the retractor blade connects to the screw mount. According to another aspect of the invention it is provided a retractor blade assembly comprising: a pedicle screw having a head portion and a shaft portion configured to engage bone; a tulip screw mount comprising a tulip with a closed end defining a screw head seat and extension legs extending proximally from the tulip with a slot extending therebetween; and a retractor blade having a body extending between a proximal end and a distal end configured to retract soft tissue, the retractor blade body defining a rail configured to be received in the screw mount slot to retain the retractor blade on the tulip screw mount. In a version the rail is tapered from a free end thereof toward the retractor blade body such that the retractor blade is radially fixed relative to the tulip screw mount. In another version the retractor blade is axially moveable relative to the tulip screw mount. Advantageously the retractor further comprises a pivot connection proximate the proximal end of the retractor blade. The pivot connection may be formed in a version integrally with the retractor blade proximal end. In another version the pivot connection is formed by a cap which connects to proximal ends of the leg extensions. In another version the pivot connection includes a through hole configured to receive a post of a retractor arm. In another version the retractor includes a plurality of teeth about the through hole which are configured for engagement with teeth on the retractor arm. In another version the retractor further comprises a shim positioned in the slot between the blade and the tulip closed end. In a version breaking features are provided between the tulip and the extension legs. It is further described a method of connecting a retractor blade to a pedicle, the method comprising: connecting a driver to a screw mount, the screw mount including an extension portion and a head portion, the head portion having a concave internal wall and the extension portion including a moveable retaining member with a free end that extends into the head portion such that a concave surface of the retaining member is opposed to the concave internal wall to define a screw head chamber; positioning the head of a pedicle screw within the chamber; moving a locking mechanism to a locking position wherein a portion of the locking mechanism engages the retaining member and prevents the retaining member from moving radially outwardly; attaching the pedicle screw to a pedicle of the vertebra; sliding a retractor blade having a proximal portion and a distal portion down the driver and onto the screw mount such that the distal portion of the retractor blade connects to the screw mount; and removing the driver.

The present embodiments will become more fully understood from the detailed description and the accompanying drawings. The invention is shown in particular in the <FIG>, the remaining figures are reported for a better understanding of the invention, wherein:.

Embodiments of the disclosure are generally directed to devices, systems for retraction and/or distraction using a pedicle-based retraction system. Specifically, the pedicle-based retractors include secure and reversible connections between the pedicle screw and retractor blade. The retractor blade may be attached to the screw before or after the screw has been implanted in the bone. When attached intra-operatively, the attachment mechanism may minimize the amount of tissue disruption at the surgical site.

In a spinal fusion procedure, a damaged spinal disc may be removed and replaced with an intervertebral implant (e.g., a cage, spacer, vertebral body replacement, bone graft material, or other prosthetic). The adjacent vertebrae may be stabilized, for example, with a combination of screws and rods. The operation may be performed in an open procedure, semi-open procedure, percutaneous, or in a minimally invasive surgical (MIS) procedure. As part of the procedure, a retractor may be used to establish, enlarge, manipulate, and/or maintain a surgical opening, thereby facilitating the passage of the various implant devices and related tools. In some instances, different retractors may be used for different surgical approaches (e.g., anterior, posterior, transforaminal, lateral), due to the varying anatomical features unique to each approach. The retractor blades may be used to hold back soft tissue and muscle, and precise angling of the retractor's blades may depend at least in part on various factors, including the particular patient's anatomy and surgeon's preference.

Overall, retractor systems disclosed herein may advantageously provide a screw-based retraction and distraction, resulting in more precise tissue retraction and distraction of adjacent bones. In particular, a pedicle-based retraction system may include one or more retractor blades temporarily affixed to one or more pedicle screws each configured to engage a pedicle of a vertebra. Once attached to a retractor body, the retractor blades and attached pedicles may retract soft tissue and/or muscle and distract the disc space. Although described herein with regards to specific pedicle-based blade designs, those skilled in the art may appreciate that the blades described herein may be used in any suitable retractor design.

As used herein, the terms "proximal" and "distal" are utilized generally with reference to a user (e.g., a surgeon). When used with reference to the retractor assembly, described further herein, the terms "lateral" and "medial" refer generally to the ends and the middle position, respectively. For example, a retractor arm traveling in a lateral direction may be traveling from a middle portion outwardly, and a retractor arm traveling in a medial direction may be traveling from an end portion towards the middle. These and other directional terms such as "top" and "bottom" and the like may be used herein for descriptive purposes and do not limit the orientation(s) in which the devices may be used.

Some embodiments may include a two-bladed retractor. The retraction may be controlled medially and laterally, for example. Each blade may also have a towing or pivoting capability. Although a two blades design is exemplified, it is understood that the retractor may encompass three or more blades, four or more blades, or the like in order to provide retraction in the medial, lateral, cephalad, caudal, or other orientations as may be desired.

The retractor system may include a variety of sub-components dimensioned to allow for retraction of soft tissue and/or muscle in order to establish an operative corridor through a patient's skin to a surgical target site as well as a screw-based component to allow for distraction of adjacent bones. By way of example, the surgical target site may be an intervertebral disc space situated between two adjacent vertebrae. Although particularly suited for use in a transforaminal lumbar interbody fusion (TLIF), it will be readily appreciated by those skilled in the art that the retractor system may be employed in any number of suitable orthopedic approaches and procedures, including but not limited to, anterior, posterior, lateral, anterolateral, or posterolateral approaches to the lumbar spine, cervical spine, or thoracic spine, as well as any non-spine application, such as treatment of bone fractures and the like.

Turning now to the drawing, where like reference numerals refer to like elements, <FIG> illustrates a retractor system <NUM>. The retractor system <NUM> includes a frame or base <NUM> that is attachable to an arm and/or supporting structure (not shown). For example, the base <NUM> may be directly or indirectly attachable to a table, a rack, a cart, or the like. In one embodiment, the base <NUM> is configured to be attached to a surgical arm, such as a universal arm, which includes enough joints to provide a desired number of degrees of freedom to easily adjust the base <NUM> over an incision in a patient. Preferably, the base <NUM> is configured to be positioned in a substantially stationary position over the surgical access site.

Broadly, the base <NUM> provides a scaffold to hold the various components together and one or more mechanisms for operating the retraction and/or distraction. In particular, the base <NUM> provides a mechanism to expand the operative corridor by moving the retractor blades <NUM> toward or away from one another. The base <NUM> may include one or more arms or posts <NUM> configured to receive or attach to one or more blades <NUM> thereto. Each post <NUM> is configured to enable the retractor blades <NUM> to retract nearby soft tissue and/or distract a bone segment. The base <NUM> includes one or more knobs <NUM> configured to operate the retractor <NUM>. For example, the knobs <NUM> may provide for movement of posts <NUM>, thereby providing for movement of the blades <NUM>. Each of the respective knobs <NUM> may provide for independent movement of each respective blade <NUM> including lateral movement, medial movement, pivoting or towing or the blades <NUM>, or the like as will be recognized by one of ordinary skill in the art. Although one type of retractor <NUM> is exemplified herein, it is understood that any suitable retractors known in the art may be used. Further detail of such devices may be found, for example, in <CIT>; <CIT>; <CIT>; and<CIT>.

One or more blades <NUM> are removably coupled to the base <NUM>. The position of each retractor blade <NUM> can be changed independent from the other retractor blades <NUM>, which allows a great amount of flexibility to the surgeon to explore an operating field. Furthermore, the position of each retractor blade <NUM> can be changed without changing the position of the base <NUM>. Thus, the base <NUM> may remain in a substantially stationary and fixed position over the incision. In this regard, a change in the operating field can be obtained by changing the position of the blades <NUM>.

In general, each retractor blade <NUM> has a first, proximal end portion <NUM> configured to engage with the base <NUM>, for example, having an opening to receive post <NUM> and a second, distal end portion <NUM> configured to connect with a screw member <NUM>. Each blade also includes an inner face, an outer face, and a longitudinal axis running the length of the blade <NUM> from the proximal end <NUM> to the opposite distal end <NUM>. Different blade geometries may be used based on the patient anatomy and surgeon preference. For example, the blades <NUM> may be provided with a convexity at the proximal end <NUM> to cup under tissue and muscle to prevent the blades <NUM> and retractor from floating upward. In one embodiment, the retractor blades <NUM> have a curved or partial cylindrical shape, such that when blades <NUM> are aligned adjacent one another, a cylinder, channel, cannula, or the like is created therebetween. The size of the retractor blades <NUM> may dependent on the type of surgical procedure. The type, size, and shape of the surgical retractor blades <NUM> can be mixed together as well as changed or renewed during a surgical procedure.

The screw member <NUM> is configured to be removably attached to the retractor blade <NUM> as described in the various embodiment provided herein. The screw member <NUM> may include a head portion <NUM> (e.g., an enlarged head <NUM>) at a proximal end configured to engage the retractor blade <NUM> and a shank or bone engagement portion <NUM> configured to engage bone, for example, having a taper at a distal end. The screw member <NUM> may be centrally cannulated along a longitudinal length from the proximal end to the distal end of the screw member <NUM>, for example, such that the screw member <NUM> may be guided over a k-wire or the like. The screw member <NUM> may be in the form of a pedicle screw <NUM> having a threaded portion configured to engage the pedicle in a vertebral body. The head portion <NUM> may also be threaded or non-threaded. The pedicle screw <NUM> may be configured to provide uni-planar, bi-planar, or poly-axial orientation of the shank, for example. In the alternative, the screw member <NUM> may include any fixation members, such as nails, spikes, shims, or the like, which are known in the art.

With reference on <FIG>, a system and method for attaching a pedicle screw member <NUM> to a blade <NUM> is provided. In particular, a shim or screw mount <NUM> connects the pedicle screw member <NUM> to the blade <NUM>. The shim or screw mount <NUM> includes an extension portion <NUM> and a head portion <NUM>. The extension portion <NUM> may include a track <NUM>, for example, in the form of one or more recesses and/or protrusions extending along a longitudinal length of the extension portion <NUM>. The track <NUM> is configured to slidably engage and mate with a corresponding track portion <NUM> on a driver <NUM>. The head portion <NUM> of the screw mount <NUM> may be sized and configured to receive the head <NUM> from the screw member <NUM>. In particular, the head portion <NUM> may define an opening or aperture <NUM> configured to allow for side-loading of the screw member <NUM>. The head portion <NUM> may house an internal sphere <NUM> within. The internal sphere <NUM> may be sized and configured to rotationally reside within the head portion <NUM> of the screw mount <NUM>. The internal sphere <NUM> may have an opening or aperture corresponding to aperture <NUM> in the head portion <NUM>, when in an unlocked position, such that the screw member <NUM> may be side loaded into the screw mount <NUM>. The internal sphere <NUM> may be rotated by driver <NUM> such that the aperture <NUM> of the head portion <NUM> is substantially blocked, thereby locking the screw member <NUM> within the head portion <NUM> of the screw mount <NUM> in a locked position.

The driver <NUM> may include a distal portion configured to engage the screw mount <NUM> and a proximal portion configured to engage a handle (not shown) or other instrumentation to be manipulated by a user (e.g., a surgeon). For example, a quick connect handle may be attached to the driver <NUM>. The driver <NUM> may include an elongated outer shaft <NUM> having an inner shaft <NUM> received longitudinally therethrough. The inner shaft <NUM> may also be cannulated along its length, for example, to be guided by a k-wire or the like. The inner shaft <NUM> may be configured to rotate with respect to the outer shaft <NUM>. The inner shaft <NUM> may terminate at a distal tip <NUM>. The distal tip <NUM> may have a hexalobular portion, for example, which engages with a portion of the screw mount <NUM>. The distal tip <NUM> may be of any suitable shape and configuration including, but not limited to, round, triangular, squared, polygonal, star, torx, irregular, uniform, non-uniform, offset, staggered and/or tapered. The outer shaft <NUM> may also include a track portion <NUM> extending longitudinally along a length of the driver <NUM>. The track portion <NUM> may be in the form of one or more extensions or recesses configured to mate with a corresponding track <NUM> on the screw mount <NUM>.

A series of steps, which may be used to install the pedicle screw <NUM> in bone and mount a retractor blade <NUM> thereto is further described. Any of these steps may be performed before or during the operation in any suitable order. The screw mounts <NUM> may be available as a kit or set, for example, in a caddy sitting upright (not shown), such that a user can use driver <NUM> to select a screw mount <NUM>. With reference on <FIG>, shown in step (a), the driver <NUM> may be pressed downward onto the screw mount <NUM>. In particular, the distal tip <NUM> of the driver <NUM> may include an extension configured to engage a corresponding recess in the top of the head portion <NUM> of the screw mount <NUM> and/or a recess in the head <NUM> of the screw member <NUM>, for example, via a press-fit connection. In addition, the track portion <NUM> on the driver <NUM> may slidably engage the track <NUM> on the extension portion <NUM> of the screw mount <NUM>. The corresponding and intermeshing tracks <NUM>, <NUM> and press-fit connection of the tip <NUM> with head portion <NUM> may provide for visual, audible, and/or tactile feel when the driver <NUM> snaps onto the screw mount <NUM>. The fully seated screw mount <NUM> on driver <NUM> is shown in step (b). After verifying the connection, a thumb knob (not shown) on the driver <NUM> can be utilized to make sure that the internal sphere <NUM> of the screw mount <NUM> is in the unlocked position (e.g., with apertures aligned to allow for side loading of the screw member <NUM>).

As shown in step (c), the screw member <NUM> may be side-loaded into the screw mount <NUM>. The hexalobular portion of the inner shaft <NUM> of the driver <NUM> may be pulled back and the screw head <NUM> inserted into the head portion <NUM> of the screw mount <NUM> from the side. The resulting construct is shown in step (d) with the screw member <NUM> received in screw mount <NUM> and attached to driver <NUM>. The hexalobular portion of the driver <NUM> may then be pushed forward and engaged with the screw <NUM> (not visible).

Turning now to <FIG>, as shown in step (e), the internal sphere <NUM> in the head portion <NUM> of the screw mount <NUM> may be rotated into the locked position. For example, a driver thumb knob may be rotated, for example, <NUM> degrees, to turn the internal sphere <NUM> to the locked position. A close up view of the screw mount <NUM> in the unlocked positioned is shown in (e1) and (e2) shows a close up view of the screw mount <NUM> in the locked position. A solid stop (not shown) may also be present to ensure that the internal sphere <NUM> remains in the locked position.

At the surgical site, a Jamshidi needle and k-wire may be placed into the pedicle. A series of cannulas may be inserted over the k-wire to dilate the tissue and obtain the blade length. The cannulas may then be removed, leaving the k-wire in place. The driver assembly, including the screw member <NUM> and screw mount <NUM> connected to the driver <NUM>, may pass over the k-wire and the screw member <NUM> may be inserted into the pedicle (e.g., threaded into the pedicle).

Turning now to <FIG>, prior to disconnecting the driver <NUM> from the screw mount <NUM>, as shown in steps (f) and (g), the blade <NUM> may be engaged with the driver <NUM>. As shown in step (h), the blade <NUM> may be slid down the side of the driver <NUM> and onto the screw mount <NUM>. In particular, the blade <NUM> may also include a track configured to engage with the track <NUM> on the outer shaft <NUM> of the driver and connect with an outer portion of the extension portion <NUM> of the screw mount <NUM>.

As best seen in <FIG>, in steps (i) and (j), once the blade <NUM> has been connected with the screw mount <NUM>, the driver <NUM> can be removed. The series of driver assembly, screw insertion, blade insertion and driver removal may be repeated at the other pedicle sites as many times as necessary for the operation. Once the screws <NUM>, screw mounts <NUM>, and blades <NUM> are in place, as shown in step (k), the retractor body <NUM> can be attached to the blades <NUM>, for example, from a side approach. As shown, the posts <NUM> can be positioned within openings in the blades <NUM>. The blades <NUM>, including the screw mounts <NUM> and screws <NUM>, and the vertebral bodies attached thereto can now be manipulated by the retractor <NUM>. For multi-level constructs, the retractor base <NUM> can be removed from the blades <NUM> and the retractor <NUM> reattached to adjacent blades <NUM>. If necessary, the blades <NUM> and/or screw mount <NUM> may be rotated about the pedicle screw member <NUM> before the retractor <NUM> is reattached to adjacent blades <NUM>.

After the interbody work has been completed, the same or a separate driver <NUM> may be introduced to turn the internal sphere <NUM> into the unlocked position. The retractor blades <NUM> can be retracted out further, thereby separating the screw member <NUM> from the screw mounts <NUM>. The pedicle screws <NUM> can remain in the pedicles and can be used for a resulting fusion procedure (e.g., combined with rods). By moving the retractor blades <NUM> outward, this will allow enough space for screw tulips to be introduced and connected to the screw members <NUM>. After rods and locking caps have been introduced, the retractor <NUM>, blades <NUM>, and screw mounts <NUM> may be removed, for example, at the same time.

<FIG> provide further details of shim or screw mount <NUM>, which may be used to connect blade <NUM> to screw <NUM>, for example. The shim or screw mount <NUM> may include extension portion <NUM> and connection portion or head portion <NUM>. The extension portion <NUM> may be in the form of an elongated member extending from a proximal end to a distal end. The extension portion <NUM> may include track <NUM> along a front surface. The track <NUM> may include one or more recesses or grooves extending along a longitudinal length of the extension portion <NUM>. The track <NUM> is configured to engage and mate with a corresponding track portion <NUM> on driver <NUM>.

The connection portion or head portion <NUM> of the screw mount <NUM> may be in the form of an outer spherical portion. The outer spherical portion of the head portion <NUM> may be generally rounded or spherical in shape and may be generally hollow within. The head portion <NUM> is preferably sized and shaped to receive at least a portion of the head <NUM> of screw member <NUM> therein. The head portion <NUM> preferably defines opening or aperture <NUM> in order to provide for side-loading of the screw member <NUM>. The bottom of the head portion <NUM> also includes an opening configured to receive a portion of the shaft of the screw <NUM>. The head portion <NUM> may be connected to the extension portion <NUM> at a distal end of the extension portion <NUM>.

The head portion <NUM> preferably retains internal sphere <NUM> within. The internal sphere <NUM> may be sized and shaped to be retained within the head portion <NUM> of the screw mount <NUM>. The internal sphere <NUM> also includes an opening configured to receive a portion of the shaft of the screw <NUM>. The internal sphere <NUM> is preferably configured to rotate with respect to the head portion <NUM> of the screw mount <NUM>. Internal sphere <NUM> may extend through an opening in the top of the head portion <NUM> such that the internal sphere is able to engage with driver <NUM>. The internal sphere <NUM> may have an opening or aperture corresponding to aperture <NUM> in the head portion <NUM>. <FIG> show an unlocked position of the internal sphere <NUM> such that the side-opening in the internal sphere <NUM> is aligned with the side-opening in the head portion <NUM>. When unlocked, the screw member <NUM> may be side loaded into the screw mount <NUM>.

<FIG> depict screw mount <NUM> in a locked position (with the screw <NUM> absent). In other words, the internal sphere <NUM> is rotated, for example, by driver <NUM>, such that the aperture <NUM> of the head portion <NUM> is substantially blocked by side wall <NUM> of the internal sphere <NUM>, thereby locking the screw member <NUM> within the head portion <NUM> of the screw mount <NUM> in the locked position.

In one embodiment, only the inner sphere <NUM> is able to rotate. In an alternative embodiment, the two spherical members <NUM>, <NUM> are each able to rotate independently of one another. Once the screw <NUM> is inserted into the internal sphere <NUM>, the internal sphere <NUM> is rotated, for example, <NUM> degrees, to block the screw head <NUM> from being removed from the direction that it was inserted. The external sphere <NUM> contains the screw <NUM> from being removed from the back side. A physical stop may be provided to give the surgeon feedback to know when the internal sphere <NUM> has been rotated to the locked position. A feature <NUM> on the top of the internal sphere <NUM> may be utilized to allow the driver <NUM> to mate with the sphere <NUM> and turn it. The feature <NUM> may include one or more recesses and/or protrusion, for example, having a round, triangular, squared, polygonal, star, torx, irregular, uniform, non-uniform, offset, staggered and/or tapered shape configured to engage with the distal tip <NUM> of the driver <NUM>. The outer sphere <NUM> is retained by the retractor blade <NUM> to keep it from spinning with the inner sphere <NUM>. The screw <NUM> can retain its ability to rotate and pivot to a desired angle. The internal sphere <NUM> can be rotated, for example another <NUM> degrees, to unblock the screw <NUM> for removal from the screw mount <NUM>.

As shown in <FIG>, the steps for inserting screw <NUM> are shown for side-loading the screw <NUM> into the mount <NUM>. In <FIG>, the head <NUM> of the screw <NUM> is aligned with the opening <NUM> in the outer sphere <NUM>. The inner sphere <NUM> is in the unlocked position. In <FIG>, the head <NUM> of the screw is inserted in the inner sphere <NUM> that is positioned inside the outer sphere <NUM>. <FIG> show driver <NUM> engaging the top of inner sphere <NUM>. <FIG> show the inner sphere <NUM> rotated to the locked position such that the side wall <NUM> of the inner sphere <NUM> blocks the aperture <NUM> of the outer sphere <NUM>.

Turning now to <FIG>, another mechanism of attachment between the retractor blade <NUM> and the pedicle screw <NUM> is shown. In particular, <FIG> depicts a front view of the blade assembly <NUM> including screw mount or shim <NUM> connecting the pedicle screw <NUM> to the retractor blade <NUM>. In this design, the screw mount or shim <NUM> wraps around the outer edges of the blade <NUM> to keep it in place. <FIG> depicts a side view of an edge <NUM> of the shim <NUM> engaged with the blade <NUM>. The blade <NUM> extends from a proximal end portion <NUM> to a distal end portion <NUM> configured to engage with and retract soft tissues and/or muscle. The blade <NUM> has a generally curved inner portion configure to mate with a generally curved portion of the shim <NUM>. The blade <NUM> includes two extensions or end portions <NUM> at the outer most portions of the curved blade. These end portions <NUM> may extend along a portion or an entire length of the blade <NUM> from the proximal end <NUM> to the distal end <NUM>. The shim <NUM> includes extension portions with edges <NUM> configured to surround the end portions <NUM> of the blade <NUM>. <FIG> shows a top view of the assembly <NUM>.

When installing the assembly <NUM> or a portion thereof, the bone screw <NUM> may be threaded in to the pedicle and the screw mount <NUM> may be added before or after the bone screw <NUM> is engaged with the pedicle. With the bone screw <NUM> and shim <NUM> in place, the retractor blade <NUM> slides into the shim <NUM>. One or more locks <NUM> (e.g., two locks <NUM> shown in <FIG>) may be provided on the outer edges or end portions <NUM> of the blade <NUM> such that the locks <NUM> engage once the screw <NUM> is fully engaged inside the bone. One or more stops <NUM> (e.g., two stops <NUM> shown in <FIG>) may also be provided on the blade <NUM> at the distal end <NUM> to prevent the shim <NUM> from backing out proximally during the surgery. A removal slot and/or tab <NUM> may be operable by a removal tool to disengage the distal end of the shim <NUM> from the head of the screw <NUM>, thereby allowing the shim <NUM> to slide back up the outer edges of the blade <NUM> and separate from the blade <NUM>.

<FIG> depict an alternative version of a blade assembly <NUM> where the screw mount or shim <NUM> engages interior rails <NUM> on the blade <NUM>. In <FIG>, a front view of the blade assembly <NUM> is shown including screw mount or shim <NUM> connecting the pedicle screw <NUM> to the retractor blade <NUM>. In this design, the shim <NUM> slides down the interior rails <NUM> of the blade <NUM> to keep the shim <NUM> in place. <FIG> depicts a side view of the shim <NUM> engaged with the blade <NUM>. The blade <NUM> extends from a proximal end portion <NUM> to a distal end portion <NUM> configured to engage with and retract soft tissues. In one embodiment, the blade <NUM> is identical to blade <NUM> such that shim <NUM> and shim <NUM> are interchangeable with the same blade <NUM>, <NUM> design. One or more locks <NUM> (e.g., two locks <NUM> shown in <FIG>) may be provided on the outer edges or end portions of the blade <NUM>, for example, if shim <NUM> where selected.

The blade <NUM> may have a generally curved inner portion having one or more rails <NUM>, for example, in the form of channels or grooves, defined along a portion or an entire length of the blade <NUM> from the proximal end <NUM> to the distal end <NUM>. The shim <NUM> includes corresponding rails <NUM>, for example, in the form of ridges or tongues, configured to be received within and slidably engage the rails <NUM> of the blade <NUM>. <FIG> shows a top view of the assembly <NUM>. The shim <NUM> also includes a partial or complete ring <NUM> configured to at least partially surround or rest below the head portion <NUM> of the screw <NUM>. As the bone screw <NUM> is driven into the pedicle, one or more dimples may be centered inside the rails <NUM> (e.g., the outer two rails <NUM>) of the blade <NUM> that engage with the shim <NUM> while the screw <NUM> is being driven into the bone. A removal tool can be used to allow the shim <NUM> to slide back up the rails <NUM> and separate from the blade <NUM>.

Turning now to <FIG>, another mechanism of attachment between the retractor blade <NUM> and the pedicle screw <NUM> is shown. In particular, <FIG> depicts a front view of the blade assembly <NUM> including screw mount or rotating shim <NUM> connecting the pedicle screw <NUM> to the retractor blade <NUM>. In this design, the shim <NUM> is configured to rotate or spin in order to catch and lock or unlock the pedicle screw <NUM> to the blade <NUM>.

The blade <NUM> may have a generally curved inner portion having one or more rails <NUM>, for example, in the form of channels or grooves, defined along a portion or an entire length of the blade <NUM>. Similar to assembly <NUM>, the shim <NUM> may be configured to slide down the interior rail <NUM> of the blade <NUM> to keep the shim <NUM> in place. In this case, the rail <NUM> may be a single, central rail <NUM> in the form of an internal T-slot, for example. The shim <NUM> includes a corresponding rail <NUM>, for example, in the form of a ridge or tongue, configured to be received within and slidably engage the rail <NUM> of the blade <NUM>. In particular, the shim <NUM> may include a single, central T-rail <NUM>. <FIG> shows a top view of the assembly <NUM>. The shim <NUM> also includes a partial ring <NUM> configured to at least partially surround or rest beneath the head portion <NUM> of the screw <NUM>. The ring <NUM> includes an opening to allow for side loading of the screw <NUM> onto the shim <NUM>.

The pedicle screw <NUM> may be inserted into the pedicle, for example, using an open or MIS approach. The rotating shim <NUM> may be inserted into the retractor blade <NUM> via the internal T-slot <NUM> and T-rail <NUM>. The rotating shim <NUM> can be locked in place using one or more dimples, for example. With the shim <NUM> inserted, the retractor blade <NUM> and shim <NUM> can be inserted into the incision and moved (e.g., cephalad and/or caudal) until the shim <NUM> hooks onto the pedicle screw <NUM>. The shim <NUM> may or may not lock to the screw <NUM>. Once attached for all pedicles, the blades <NUM> may be attached to the retractor body. To disconnect the shim <NUM> from the screw <NUM>, a tool (e.g., a hex tool) may be configured to rotate the shim <NUM> (e.g., <NUM>°) while still in the blade <NUM>, thereby allowing for the blades to be retracted further (e.g., cephalad and/or caudal) without being attached to the pedicle screws <NUM> any further.

<FIG> depict assembly <NUM> including retractor blade <NUM>, shim <NUM>, and pedicle screw <NUM>. In this embodiment, the shim <NUM> is in the form of a split collet. For example, the shim <NUM> may include two separate arms separated by a longitudinal slot having a ring <NUM> at a distal-most end. A slight interference between the collet <NUM> and screw head <NUM> allows the shim <NUM> to be clicked over the shank of the screw <NUM>. The shim <NUM> may snap over the screw head <NUM> and be inserted through the incision with the pedicle screw <NUM>. Once the screw <NUM> is in place, the retractor blade <NUM> may be inserted and slid over the shim <NUM> using an internal T-slot similar to that described in assembly <NUM>. There may be no secondary locking between the screw <NUM> and the shim <NUM> and retractor blade <NUM>. Alternatively, there may be an extended groove or slot <NUM> for addition tightening. As best seen in <FIG>, as the retractor blades <NUM> slides down, there is an elongated slot <NUM> in the shim interference causing the collet <NUM> to tighten further, thereby better locking screw <NUM> to the shim <NUM>. With the blades <NUM> connected to the shims <NUM> and screws <NUM>, the retractor can be attached to the retractor blades <NUM>. To remove the shim <NUM>, a separate tool can be used to loosen the connection between the shims <NUM> and the screw <NUM> to remove the shim <NUM> from the retractor blade <NUM>.

<FIG> illustrate an alternative embodiment for attachment between the pedicle screw <NUM> and the blade <NUM>. In this embodiment, the screw <NUM> is directly attached to the blade <NUM> using a wire, filament, fiber, or cable <NUM>. The cable <NUM> may include any suitable elongate element configured to engage the pedicle screw and the blade <NUM> at one or more points of contact. For example, the retractor blade <NUM> may have the cable <NUM> attached on one end, for example, at the top of the blade <NUM>. The cable <NUM> may be routed down the blade tip where it will form a hoop and be routed back up to the top of the blade <NUM>. The cable <NUM> may extend through one or more openings in the blade <NUM>, for example. The shank of the screw <NUM> may be threaded into the pedicle using a driver, for example. Prior to removing the driver, a slackened hoop of cable <NUM> may be placed around the driver and the blade <NUM> may be inserted down the incision using the driver as a guide. Once the retractor blade <NUM> reaches its predetermined depth, the cable <NUM> can be tightened, for example, using one or more thumb knobs <NUM>, thereby taking up the slack and tightening the cable <NUM> around the screw <NUM>. Thumb knobs <NUM> may be in the form of wheels or cylinders, for example, attached to the proximal end of the blade <NUM>. The thumb knobs <NUM> may be configured to rotate such that the cable <NUM> winds around the base of the knobs <NUM>. The driver can then be detached and removed from the incision. If needed, distraction of the disc space can take place, for example, using the pedicle screws <NUM>. To remove the retractor blade <NUM> from the screw <NUM> after the retraction is no longer needed, the cable <NUM> can be slacked again or disconnected entirely from one or both ends. As the blades <NUM> are removed, the cable <NUM> can unwind and pull free from the screw <NUM>.

Referring to <FIG>, a screw mount <NUM> in accordance with another embodiment which is configured to connect the pedicle screw member <NUM> to a blade <NUM> will be described. The mount <NUM> includes an extension portion <NUM> and a head portion <NUM>. In the illustrated embodiment, the extension portion <NUM> defines tracks <NUM>, <NUM> and <NUM>, for example, in the form of recesses extending along a longitudinal length of the extension portion <NUM>. The track <NUM> is configured to receive a slidable locking mechanism <NUM> (see <FIG>), as will be described in more detail hereinafter. The tracks <NUM> and <NUM> are configured to slidably engage and mate with rails on a corresponding blade <NUM>, as will be described with reference to <FIG>. The outside surfaces of the extension portion <NUM> opposite of the tracks <NUM> define an external track configured to mate with a corresponding track portion <NUM> on a driver <NUM>, as will be described with reference to <FIG>. The extension portion <NUM> of the illustrated mount <NUM> also defines a pair of driver mating openings <NUM> and a pair of blade mating openings <NUM>. Each of the driver mating openings <NUM> is open to receive a biased tab <NUM> on the drive <NUM> as illustrated in <FIG>. A biased retaining member <NUM> is positioned in each blade mating opening <NUM> and includes a lip <NUM> configured to engage a slot <NUM> in the blade <NUM> as illustrated in <FIG>.

The head portion <NUM> of the screw mount <NUM> is sized and configured to receive the head <NUM> from the screw member <NUM>. In particular, the head portion <NUM> in the current embodiment defines an internal, concave wall <NUM> about a chamber <NUM> with end openings <NUM> and <NUM>. The screw head <NUM> may be positioned in the chamber <NUM> by passing through either end opening <NUM>, <NUM>. In the illustrated embodiment, the head <NUM> is configured with a stop <NUM>, such that the screw head <NUM> is received through opening <NUM> and contacts the stop <NUM> to properly align the screw head <NUM> within the concave surfaces <NUM>, <NUM>. The chamber <NUM> generally has a diameter larger than the diameter of the screw head <NUM>. A retaining member <NUM> having a body <NUM> extends from the extension portion <NUM> such that a free end <NUM> thereof extends into the chamber <NUM>. The free end <NUM> defines a concave surface <NUM> which engages a portion of the screw head <NUM> such that the screw head <NUM> is retained between the inner wall surface <NUM> and the free end surface <NUM>. The surfaces <NUM>, <NUM> hold above and below the centerline of the screw head <NUM> so that the screw <NUM> cannot be removed in an up or down movement. Slits <NUM> in the extension portion <NUM> allow the free end <NUM> of the retaining member <NUM> to move radially outward as the screw head <NUM> enters or exits the chamber <NUM>. The retaining member <NUM> is biased to an inward, engaging position. Even in the engaged position, the chamber <NUM> is slightly oversized relative to the screw head <NUM> to ensure a loose fit and easy screw manipulation without damaging the screw head features. The screw <NUM> will be able to rotate and pivot without resistance.

Referring to <FIG>, the locking mechanism <NUM> is slidable along the track <NUM> from an unlocked position (<FIG>) to a locked position (<FIG>). The locking mechanism <NUM> includes an elongate body <NUM> with a head <NUM> at the proximal end and an engagement portion <NUM> at the distal end. In the locked position, the head <NUM> is depressed such that the engagement portion <NUM> moves into engagement with the free end <NUM> of the retaining mechanism <NUM>, thereby locking the free end surface <NUM> in engagement with the screw head <NUM>. As will be described hereinafter, the head <NUM> may be depressed manually and retained by the blade <NUM>. For entry or removal of the screw head <NUM> from the chamber <NUM>, the locking mechanism <NUM> is moved to the unlocked position illustrated in <FIG>. In the unlocked position, the engagement portion <NUM> is aligned with a notch <NUM> in the body <NUM> of the retaining member <NUM>, such that the free end <NUM> may move radially outwardly to allow the screw head <NUM> to pass. Contact surfaces <NUM>, <NUM> in the notch <NUM> and on the engagement portion <NUM> define a stop for the locking mechanism <NUM>.

Turning to <FIG>, a system and method for attaching a pedicle screw member <NUM> to a blade <NUM> utilizing the screw mount <NUM> will be described. Referring to <FIG>, the driver <NUM> includes a body <NUM> extending between a proximal end and a distal end with the distal end defining distal portions <NUM> configured to engage the screw mount <NUM>. Each distal portion <NUM> defines an internal track <NUM> configured to receive and engage a portion of the extension portion <NUM>. Each distal portion <NUM> also includes a biased tab <NUM> configured to engage a respective driver mating opening <NUM> on the extended portion <NUM> of the screw mount. The biased tabs <NUM> releasably retain the driver <NUM> on the screw mount <NUM>.

Referring to <FIG>, <FIG>, the driver body <NUM> defines a driver tool slot <NUM> extending from the proximal end to the distal end. In the illustrated embodiment, a cylindrical guide <NUM> extends from the proximal end of the body <NUM> about the slot <NUM> to assist in maintaining the driver tool <NUM> aligned within the slot <NUM>. The driver tool <NUM> includes a distal tip <NUM> configured to engage the screw <NUM>. The distal tip <NUM> may be of any suitable shape and configuration including, but not limited to, round, triangular, squared, polygonal, star, torx, irregular, uniform, non-uniform, offset, staggered and/or tapered. The body <NUM> of the driver <NUM> also defines one or more tracks <NUM>, <NUM> on the rear surface thereof. The tracks <NUM>, <NUM> are configured to guide the respective blade <NUM>. As shown in <FIG>, the illustrative blade <NUM> includes a body <NUM> extending from a proximal end to a distal end, with outer rails <NUM> and a central rail <NUM> defining slots <NUM>. The outer rails <NUM> align with the tracks <NUM> and the central rail <NUM> aligns with the track <NUM>.

A series of steps, which may be used to install the pedicle screw <NUM> in bone and mount a retractor blade <NUM> thereto is further described. Any of these steps may be performed before or during the operation in any suitable order. The screw mounts <NUM> may be available as a kit or set, for example, in a caddy sitting upright (not shown). With reference on <FIG>, as an initial step, a desired number of screw mounts <NUM> will be attached to respective drivers <NUM>. The secondary slot <NUM> in the distal end of the driver body <NUM> receives the head portion <NUM> of the locking mechanism <NUM> such that the locking mechanism <NUM> remains in the unlocked position. With the locking mechanism <NUM> in the unlocked position, a screw <NUM> of a desired length will be inserted through the bottom opening <NUM> of the head portion <NUM>. With the screw head <NUM> within the chamber <NUM>, the head <NUM> of the locking mechanism <NUM> is depressed to move the locking mechanism <NUM> to the locked position such that the screw <NUM> is locked in place as shown in <FIG>. The driver tool <NUM> is positioned within the driver slot <NUM> and the distal tip <NUM> of the driver tool <NUM> engages the screw head <NUM> as illustrated in <FIG> and <FIG>.

At the surgical site, a Jamshidi needle and k-wire may be placed into the pedicle. A series of cannulas may be inserted over the k-wire to dilate the tissue and obtain the blade length. The cannulas may then be removed, leaving the k-wire in place. The driver assembly, including the screw member <NUM> and screw mount <NUM> connected to the driver <NUM>, may pass over the k-wire and the screw member <NUM> may be inserted into the pedicle (e.g., threaded into the pedicle). To reduce tissue disruption, the driver <NUM> along with the screw mount <NUM> will be free to spin independent of the driver tool <NUM>. With the screw <NUM> at the necessary depth, the required blade length may be measured off of the driver <NUM>.

Turning now to <FIG>, prior to disconnecting the driver <NUM> from the screw mount <NUM>, the blade <NUM> may be engaged with the driver <NUM>. With a blade handle (not shown) attached to the blade <NUM>, the blade <NUM> will be inserted from the top down with the outer rails <NUM> engaging with the tracks <NUM> and the central rail <NUM> engaging with the track <NUM>. <FIG> illustrate the interconnection of the blade <NUM> with the screw mount <NUM>. In these figures, the driver <NUM> is omitted for clarity, however, the driver <NUM> will be maintained in position until the blade <NUM> is fully inserted. Referring to <FIG>, as the blade <NUM> is inserted, the outer rails <NUM> are received in the tracks <NUM> and the central rail <NUM> is received in the track <NUM>. As shown in <FIG>, as the blade <NUM> moves into the screw mount <NUM>, the lip <NUM> of each biased retaining member <NUM> is received in a respective slot <NUM> in the blade <NUM>. The distal end <NUM> of the slot <NUM> defines a stop for the lip <NUM>. The engagement of the lip <NUM> within the slot <NUM> defines a range of motion over which the blade <NUM> is axially moveable relative to the screw mount <NUM>. In at least one embodiment, the blade <NUM> and screw mount <NUM> will have at least <NUM> of passive translation between them.

With the blade <NUM> connected to the screw mount <NUM>, the driver <NUM> will then be disconnected and removed from the screw mount <NUM> and blade <NUM> by pulling up on it, as illustrated in <FIG>. The blade handle on the blade <NUM> will be used to maneuver the initial blade to allow for easy insertion of additional screws, screw mounts, and drivers, as desired. The respective blades will be introduced in the same fashion as the first.

In one exemplary procedure utilizing the blades <NUM> and screw mounts <NUM>, after the screws, screw mounts, and blades are inserted in the pedicles, the retractor will be introduced in a manner to that described above. The cranial and caudal retractor arms will be able to freely slide to easily align with the blades. The retractor will be attached from a side approach in the lateral position. The blades will automatically lock onto the retractor posts at any angle through the use of two mating stargrinds. A spring loaded button on the blades will slide into a groove on the retractor post to rigidly lock them together. The retractor arms will then be reengaged and able to be independently retracted with the use of a hex driver. The use of a worm drive will allow the blade to pivot an infinite amount in either direction.

With the blades positioned as desired, a medial arm and blade will be attached to the retractor. The arm will attach to the retractor from a top down approach and the medial blade will attach to the medial arm from an in line approach. The arm will include a linear retraction mechanism and a passive translation mechanism to allow the blade to be positioned midway between the cranial and caudal blades. The arm will also contain a mechanism to angle the blade in a medial/lateral direction. A blade handle will attach to the blade for easier control during manual retraction prior to attaching to the arm. The medial blade will utilize a passive translation member to allow the blade to be lengthened or shortened as desired. Likewise, a lateral arm and blade may be attached and utilized.

At the end of the case, the surgeon will disconnect the screw mounts from the screws, attach modular MIS tulips, for example, remove the medial and lateral blades and remove the cranial and caudal blades and the retractor. The remainder of the case, insertion of the rod and locking caps, may be performed, for example, using traditional MIS techniques.

The system and method, described with respect to <FIG>, provide a combined capability of retracting and distracting via secure attachment from the blade to the screw. Top down loading of the screw allows for in-situ attachment if necessary. Additionally, the driver acts as dilator for the blade to slide over with less tissue disruption. As an additional benefit, the system provides the ability to lock and unlock from the screw without having to disconnect the blade mount from the blade. Additionally, distraction forces will be on the front half of the sphere which is a part of the strong vertical segment. Passive screw mount translation allows the blades lengths to match any patient anatomy and allows the retractor to sit perfectly on each patient's skin level. Additionally, the passive translation along with the rigid connection of the screw mount to the screws allows the surgeons to pivot the retractor in the cranial/caudal direction as needed without having any tissue creep.

Turning to <FIG>, a system and method for attaching a pedicle screw member <NUM> to a blade <NUM> utilizing a tulip screw mount <NUM> will be described. The tulip screw mount <NUM> has a slotted configuration having legs defined by a distal body portion <NUM> that project upwardly from a closed end <NUM> of the tulip screw mount <NUM>. Leg extensions <NUM> extend from the body portion <NUM> above a breakaway feature <NUM> that is cut into and partially through an external surface of the tulip screw mount <NUM>. The breakaway features <NUM> can be cut into the tulip body <NUM> in any number of known manners. An open slot <NUM> extends from the proximal end <NUM> of the tulip screw mount <NUM> to the closed end <NUM>. The closed end <NUM> defines a seat <NUM> for a screw head <NUM>.

The blade <NUM> includes a linear blade body <NUM> with a pair of side rails <NUM> and a central rail <NUM> extending the length thereof. A slot <NUM> extends between the central rail <NUM> and each respective side rail <NUM>. The central rail <NUM> is configured to be received in the slot <NUM> defined by the tulip screw mount <NUM> as shown in <FIG>. In the illustrated embodiment, the central rail <NUM> is tapered from the free end thereof to the body <NUM> such that the blade <NUM> is maintained connected to the tulip screw mount <NUM>.

Once the blade <NUM> is positioned within the slot <NUM>, a cap <NUM> is secured on the proximal end <NUM> of the tulip screw mount <NUM>. The cap <NUM> has a body <NUM> extending from a connection end <NUM> to a pivot end <NUM>. The connection end <NUM> includes openings thereinto (not shown) which receive and secure the proximal ends of the leg extensions <NUM> as the cap is moved onto the tulip screw mount <NUM>, as indicated by arrow A in <FIG>. With the cap <NUM> secured on the leg extensions <NUM>, the blade <NUM> is secured relative to the tulip screw mount <NUM>, however, in the illustrated embodiment, the blade <NUM> and mount <NUM> are configured such that the blade <NUM> is able to translate up and down, as indicated by arrow B in <FIG>, relative to the tulip screw mount <NUM>. The pivot end <NUM> of the cap <NUM> includes a transverse through hole <NUM> configured to receive a post <NUM> of a retractor system as will be described hereinafter. A plurality of teeth <NUM> extend about the through hole <NUM> on each side of the cap body <NUM>.

In an exemplary procedure utilizing the screws <NUM>, tulip screw mounts <NUM> and blades <NUM>, the surgeons will begin by creating an oblique posterior incision from pedicle to pedicle on one side of the patient and place the MIS screws <NUM> with the tulip screw mounts <NUM> into the pedicles. Having the tulip screw mounts <NUM> already assembled to the pedicle screws <NUM> allows the connection to be verified prior to insertion into the incision, which will prevent the screw <NUM> from being placed too deep, and eliminates the need to later attach the tulips in-situ.

With the driver still attached to the screws <NUM> and acting as a guide, blades <NUM> are slid down the tulip screw mounts <NUM>, with the central rail <NUM> extending into the slot <NUM>, to help retract tissue. The blades <NUM> will be moveable within the tulip screw mounts <NUM> with the ability to translate up and down with respect thereto. The upward movement is unrestricted and allows the blade <NUM> to be removed from the tulip screw mounts <NUM> while a downward movement is restricted by the closed end <NUM> and bony anatomy. This translation allows the surgeon to place the blade <NUM> at the ideal height to reduce the most amount of tissue creep.

With the blades <NUM> in place and the driver removed, a cap <NUM> is fixed to the top of each tulip screw mounts <NUM> and is axially and rotationally fixed thereto as described above. Referring to <FIG>, the through hole <NUM> on each cap <NUM> receives the post <NUM> of a respective retractor arm <NUM>. Teeth <NUM> about the post <NUM> are configured to engage the teeth <NUM> such that the cap <NUM>, and thereby the blade <NUM>, may be attached to the retractor arm <NUM> at any desired angle. Once connected to the arms <NUM>, the tulip screw mounts <NUM>, and subsequently the blades <NUM>, will be able to angulate relative to the arms through the use of an angulation mechanism on the retractor arms as well as retract through the use of the retraction mechanism on the retractor frame.

After the interbody cage has been placed, the blades <NUM> will be slid up slightly but not out of the tulip screw mounts <NUM>. This new position will allow a rod to be introduced into the tulip body <NUM> and under the blade <NUM> while the blade <NUM> continues to retract soft tissue along the remaining portion of the tulip screw mounts <NUM>. To complete the construct, set screws may be introduced prior to detaching the retractor. Before removing the blade <NUM> from the incision, a rocking motion may be applied to each blade <NUM> to break off the extended legs <NUM> at the breaking features <NUM>.

The blade <NUM> includes a linear blade body <NUM> with a pair of side rails <NUM> and a central rail <NUM> extending the length thereof. A slot <NUM> extends between the central rail <NUM> and each respective side rail <NUM>. The central rail <NUM> is configured to be received in the slot <NUM> defined by the tulip screw mount <NUM> when the blade <NUM> is inserted into the slot <NUM>, as indicated by arrow C in <FIG>. In the illustrated embodiment, the central rail <NUM> is tapered from the free end thereof to the body <NUM> such that the blade <NUM> is maintained connected to the tulip screw mount <NUM>. As such, the blade <NUM> can be translated axially relative to the tulip screw mount <NUM>, as indicated by arrow D in <FIG>, but otherwise is fixed thereto.

The proximal end of the blade <NUM> includes a pivot connection <NUM>. The pivot connection <NUM> has a body <NUM> extending from a connection end <NUM> to a pivot end <NUM>. The connection end <NUM> is fixed to the proximal end of the blade body <NUM>. The pivot end <NUM> of the pivot connection <NUM> includes a transverse through hole <NUM> configured to receive a post <NUM> of a retractor system as will be described hereinafter. A plurality of teeth <NUM> extend about the through hole <NUM> on each side of the cap body <NUM>.

Referring to <FIG>, the through hole <NUM> on each pivot connection <NUM> receives the post <NUM> of a respective retractor arm <NUM>. Teeth <NUM> about the post <NUM> are configured to engage the teeth <NUM> such that the pivot connection <NUM>, and thereby the blade <NUM>, may be attached to the retractor arm <NUM> at any desired angle. Once connected to the arms <NUM>, the tulip screw mounts <NUM>, and subsequently the blades <NUM>, will be able to angulate relative to the arms through the use of an angulation mechanism on the retractor arms as well as retract through the use of the retraction mechanism on the retractor frame.

Turning to <FIG>, a system and method for attaching a pedicle screw member <NUM> to a blade <NUM> utilizing a tulip screw mount <NUM> will be described. The tulip screw mount <NUM> has a slotted configuration having legs defined by a distal body portion <NUM> that project upwardly from a closed end <NUM> of the tulip screw mount <NUM>. Leg extensions <NUM> extend from the body portion <NUM> above a breakaway feature <NUM> that is cut into and partially through an external surface of the tulip screw mount <NUM>. The breakaway features <NUM> can be cut into the tulip body <NUM> in any number of known manners. An open slot <NUM> extends from the proximal end <NUM> of the tulip screw mount <NUM> to the closed end <NUM>. The closed end <NUM> defines a seat <NUM> for a screw head <NUM>. A shim <NUM> having a cylindrical body <NUM> and a projection <NUM> are configured to be positioned within the closed end <NUM> of the tulip screw mount <NUM> as indicated by arrow E in <FIG>. The shim <NUM> is positioned such that the cylindrical body <NUM> is within the slot <NUM> and the projection <NUM> extends radially therefrom.

The blade <NUM> includes a linear blade body <NUM> with a pair of side rails <NUM> and a central rail <NUM> extending the length thereof. A slot <NUM> extends between the central rail <NUM> and each respective side rail <NUM>. The central rail <NUM> is configured to be received in the slot <NUM> defined by the tulip screw mount <NUM> when the blade <NUM> is inserted into the slot <NUM>, as indicated by arrow F in <FIG>. In the illustrated embodiment, the central rail <NUM> is tapered from the free end thereof to the body <NUM> such that the blade <NUM> is maintained connected to the tulip screw mount <NUM>. As such, the blade <NUM> can be translated axially relative to the tulip screw mount <NUM>. As shown in <FIG>, the blade <NUM> contacts the shim <NUM> and is thereby maintained spaced from the closed end <NUM> of the tulip screw mount <NUM>.

With the driver still attached to the screws <NUM> and acting as a guide, the shims <NUM> are slid into the slot <NUM> and then blades <NUM> are slid down the tulip screw mounts <NUM>, with the central rail <NUM> extending into the slot <NUM>, to help retract tissue. The blades <NUM> will be moveable within the tulip screw mounts <NUM> with the ability to translate up and down with respect thereto. The upward movement is unrestricted and allows the blade <NUM> to be removed from the tulip screw mounts <NUM> while a downward movement is restricted by the closed end <NUM> and bony anatomy. This translation allows the surgeon to place the blade <NUM> at the ideal height to reduce the most amount of tissue creep.

Referring to FIGS. 13D-13ED, the through hole <NUM> on each pivot connection <NUM> receives the post <NUM> of a respective retractor arm <NUM>. Teeth <NUM> about the post <NUM> are configured to engage the teeth <NUM> such that the pivot connection <NUM>, and thereby the blade <NUM>, may be attached to the retractor arm <NUM> at any desired angle. Once connected to the arms <NUM>, the tulip screw mounts <NUM>, and subsequently the blades <NUM>, will be able to angulate relative to the arms through the use of an angulation mechanism on the retractor arms as well as retract through the use of the retraction mechanism on the retractor frame.

After the interbody cage has been placed, the surgeon may disconnect and remove the shim <NUM> from the tulip screw mount <NUM> and blade <NUM>. This will provide space for rod and locking cap insertion while the blades <NUM> continue to retract soft tissue. Before removing the blade <NUM> from the incision, a rocking motion may be applied to each blade <NUM> to break off the extended legs <NUM> at the breaking features <NUM>.

The systems and methods described with respect to the embodiments in <FIG> provide secure attachment from the retractor to the screw allow for retraction and distraction of the disc space. Additionally, passive translation between the blade and tulip or blade and shim allows the blade's length to match any patient anatomy and allows the retractor to sit perfectly on each patient's skin level. Furthermore, the tulips are attached to the screw shanks before being inserted which allows for verification of connection, prevents placing the screws too deep, and eliminates the need to attach tulips in-situ at the end of the case.

Components of all of the devices disclosed herein can be made of materials known to those skilled in the art, including metals (e.g., titanium), metal alloys (e.g., stainless steel, cobalt-chromium, and titanium alloys), ceramics, polymers (e.g., polyether ether ketone (PEEK), polyphenylene sulfone (PPSU), polysulfone (PSU), polycarbonate (PC), polyetherimide (PEI), polypropylene (PP), polyacetals, or mixtures or co-polymers thereof), allograft, and/or combinations thereof. In some embodiments, the devices may include radiolucent and/or radiopaque materials. The components can also be machined and/or manufactured using techniques known to those skilled in the art.

Advantageously, the blades, retractor systems, and associated devices described herein can be used with a number of different implants and devices. For example, the retractor systems and devices can be used to provide access to a surgical site such that a device that preserves motion can be provided. In addition, the retractor systems and devices can be used to provide access to a surgical site such that a fusion device, such as a cage or spacer, or standalone device, can be provided. In addition, the retractor systems and devices can be used to provide access to various other devices, including but not limited to rods, screws (e.g., pedicle screws, cortical screws, etc.), plates and various other implants that are used in spine surgery.

As described herein, the specially designed connections between the pedicle screw and retractor blade provide for improved pedicle-based retraction and distraction. The connections create a secure reversible connection between the pedicle screw and the retractor blade. The connections can be made before or during the operation, and if inserted intra-operatively, the blade may be attached to and removed from the screw in a manner to minimize the amount of tissue disruption at the surgical site.

Although the invention has been described in detail and with reference to specific embodiments, it will be apparent to one skilled in the art that various changes and modifications can be made without departing from the scope of the invention. Thus, it is intended that the invention covers the modifications and variations of this invention provided they come within the scope of the appended claims.

Claim 1:
A retractor blade assembly (<NUM>) comprising:
a pedicle screw (<NUM>) having a head portion (<NUM>) and a shaft portion (<NUM>) configured to engage bone;
a retractor blade (<NUM>) having a proximal end (<NUM>) and a distal end (<NUM>) configured to retract soft tissue; and
a screw mount (<NUM>) having an extension portion (<NUM>) with at least one track (<NUM>, <NUM>) configured to slidably engage and mate with the retractor blade (<NUM>) and defining at least one blade (<NUM>) mounting assembly and
a head portion (<NUM>) defining a screw head receiving chamber (<NUM>), the chamber (<NUM>) defined by a concave interior wall (<NUM>) of the head portion (<NUM>) wherein the screw head (<NUM>) may be positioned in the chamber (<NUM>) and
a moveable retaining member (<NUM>) extending from the extension portion (<NUM>) with a free end (<NUM>) of the retaining member (<NUM>) extending within the head portion (<NUM>) and defining a concave surface (<NUM>) opposed to the concave interior wall (<NUM>); and
wherein the concave surface (<NUM>) is configured to engage a portion of the screw head (<NUM>) such that the screw head (<NUM>) is retained between the inner wall surface (<NUM>) and the free end surface (<NUM>)
wherein the blade (<NUM>) is configured to slidably engage and mate with the at least one track (<NUM>, <NUM>) of the extension portion (<NUM>); characterized in that
the extension portion (<NUM>) comprises a further track (<NUM>);
the retractor blade assembly comprises a slidable locking mechanism (<NUM>) slidable along said further track (<NUM>) from an unlocked position to a locked position,
wherein, in the locked position, the locking mechanism (<NUM>) moves into engagement with the free end (<NUM>) of the retaining mechanism (<NUM>), thereby locking the free end surface (<NUM>) in engagement with the screw head (<NUM>).