The present disclosure generally relates to fixation devices and systems for positioning and immobilizing at least two adjacent vertebrae and methods related to the same. In particular, the present disclosure relates to interbody fusion devices with angled fixation holes configured to facilitate lateral arterial implantation.
The spine is the axis of the skeleton on which all of the body parts “hang”. In humans, the normal spine has seven cervical, twelve thoracic and five lumbar segments. The lumbar spine situs upon the sacrum, which then attaches to the pelvis, and in turn is supported by the hip and leg bones. The bony vertebral bodies of the spine are separated by intervertebral discs, which act as joints but allow known degrees of flexion, extension, lateral bending, and axial rotation.
The typical vertebra has a thick anterior bone mass called the vertebral body, with a neural (vertebral) arch that arises from the posterior surface of the vertebral body. The central of adjacent vertebrae are supported by intervertebral discs. The spinal disc and/or vertebral bodies may be displaced or damaged due to trauma, disease, degenerative defects, or wear over an extended period of time. One result of this displacement or damage to a spinal disc or vertebral body may be chronic back pain. In many cases, to alleviate back pain from degenerated of herniated discs, the disc is removed along with all or part of at least one neighboring vertebrae and is replaced by an implant that promotes fusion of the remaining bony anatomy.
Although most spinal surgeries are performed using a posterior (back) approach, in some cases a surgeon may choose an anterior (ALIF) approach for various reasons, for example, to allow more direct access to the intervertebral disk; to have the ability to add more lordosis (swayback) to the d spine; and to provide access to the spine without moving the nerves. Treatment of the disc at the L5/S1 level is particularly suitable for the ALIF approach due to the efficient vascular access below with bifurcation of the aorta and inferior vena cava. However, the ALIF approach typically requires organs and blood vessels be moved to the side. As such, in many cases, a vascular surgeon assists the orthopaedic surgeon with opening and exposing the disk space.
Additionally, the ALIF approach is typically performed with the patient in a supine position. As such, other procedures, for example, attaching a plate or rod to posterior spine, will generally require changing the position of the patient to provide posterior axis. The result is often increased surgical time and reduced surgical workflow.
To meet this and other needs, an intervertebral implant has an overall footprint that matches that of a standard integrated-fixation ALIF, however, the means of attachment to the device and the angle at which the fixation is delivered, sit at an angle relative to the disc space.
According to at least one embodiment of the disclosure, an insertion tool and intervertebral implant kit is disclosed. The implant includes a body having a front end, a rear end and a pair of spaced apart first and second side walls extending between the front and rear ends. The front and rear ends extend in a transverse direction and a central axis of the body extends from the rear end to the front end. The rear end defines a first fastener hole having a first central axis and a second fastener hole having a second central axis. The first and second central axes extend parallel to one another at an acute angle relative to the body central axis in the transverse direction. The insertion tool includes a tool body extending from a proximal end to distal end. The distal end defines a face and the tool body defines at least two fastener passages with respective third and fourth central axes. The insertion tool is configured to support the implant such that the implant rear end extends along the face and the third and fourth central axes align with and are parallel to the first and second central axes, respectively, in the transverse direction.
According to at least one embodiment of the disclosure, a retraction assembly is disclosed. The retraction assembly includes a mounting plate with at least one mount extending therefrom. The mounting plate has a chamber extending therein with an adjustment screw extending into the chamber. A lateral adjustment arm has a first end with a shaft which is positioned in the chamber and engages the adjustment screw such that rotation thereof causes the lateral adjustment arm to move laterally relative to the mounting plate. The second end of the lateral adjustment arm defines a pivot mount. A pivot member is pivotally connected to the lateral adjustment arm at the pivot mount with a second adjustment screw extending from the lateral adjustment arm and engaging the pivot member such that rotation thereof causes pivoting of the pivot member relative to the lateral adjustment arm. A retraction blade connected to the pivot member.
A more complete understanding of the present disclosure, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:
Embodiments of the disclosure are generally directed to intervertebral implants, systems, and method of use thereof.
While the implant 110 is illustrated and described with a body 111 having a specific configuration, the disclosure is not limited to such. The body 111 may have various other configurations suitable for the disc space into which the implant 110 is intended. For example, the posterior end 112 may be formed with a taper or the implant 110 may have a wedge shape such that the entire body 111 tapers from the anterior end 114 to the posterior end 112. Similarly, the side walls 116, 118 may be angled toward one another rather than extending substantially parallel to one another. As yet another example, the body 111 may have an adjustable configuration. In each case, the implant body 111 will have a central axis CA extending from the anterior end 114 to the superior end 112. The central axis CA is located at the junction between the mid transverse plane P1 and the mid sagittal plane P2 and extends in each of the planes P1, P2 (see
The anterior end 114 of the implant 110 includes a plurality of fastener holes 124, 126 through which anchors 140 or screws 150 (see
Secondary holes 125 are provided to receive respective blocking set screws 160 (see
In addition to the angular orientation in the superior/inferior direction, each of the axes C1-C7 is also angled relative to the sagittal plane P2 (and thereby the central axis CA) in the transverse direction to facilitate lateral insertion of the implant 110. Referring to
The angle α is chosen to approximate the angle of the lateral insertion path A of the implant relative to the sagittal plane SP of the vertebral body 12 of the spine 10 as shown in
Having generally described the implant 110, the insertion tool 170 and implant procedure will be described in more detail with reference to
To connect the insertion tool 170 to the implant 110, a pin (not shown) extends from the tool face 175 at the location labeled 177 which aligns with the blind hole 127 of the implant. The pin extends along an axis C9 which is parallel to the tool central axis C8 such that the pin will extend into the blind hole 127 and the face 175 will extend along the anterior end 114 of the implant 110. A threaded connector (not shown) extends through a passage in the insertion tool 170 such that the threaded connector extends from the face 175 at the location labeled 178 which aligns with the threaded hole 128. The tool 170 may include a handle portion 176 through which the connector passage extends. The threaded connector passage extends along an axis C10 that is parallel with the tool central axis C8 such that the threaded connector can be advanced into and threadably engage the threaded hole 128, thereby mounting the implant 110 to the face 175 of the insertion tool 170.
The tool body 172 defines fastener passages 182, 184 (only two shown in
To access the blocking set screws 160, an opening 186 extends into the body 172 to set screw passages 188 on either side of the tube 180 defining the fastener passage 182. Each set screw passage 188 aligns with a respective secondary hole 125. The axes C14, C15 of the set screw passages 188 extend parallel to the tool central axis C8. As such, a drive tool (not shown) may be passed through each set screw passage 188 to engage and rotate a respective set screw 160. Alignment holes 189, 190 extend into each of the set screw passages 188.
While the illustrated embodiments have a fixed angle α for the holes and tool passages, it is possible to make the angle adjustable such that the implant 110 may be adjustable for different anatomies. For example, each of the implant holes could include a ball and socket configuration which is lockable at a desired angle. The face of the insertion tool could be pivotably adjustable to match the angle set for the implant holes. Other means for adjusting the angle of the holes and the tool passages may also be utilized.
The implant 110 and insertion tool 170 provide greater ease of use off-axis to disc spaces, for example, the L5-S1 disc space. Traditional ALIF implants require a straight-on approach, which is made more difficult when the patient is positioned on their side. The angled approach to the disc space with the angled tool, paired with a matching angle by which the fixation is delivered and blocked in place facilitates operating on the L5-S1 disc space, or other desired disc spaces, via a lateral position, or “lateral ALIF”.
Such lateral ALIF requires retraction of different anatomy to access the disc space with a patient on their side. Referring to
A cavity 225 extends into the mounting plate 222 and is configured to receive a shaft 242 of a lateral adjustment arm 240. The shaft 242 defines a slot 244 into which an adjustment screw 226 of the mounting plate 222 extends. The screw 226 engages within the slot 244 and thereby defines the range of later movement of the lateral adjustment arm 240. The screw 226 and slot 244 may have various adjustment configurations, for example, a friction lock, gear assembly, or a rack and pinion arrangement.
The opposite end of the lateral adjustment arm 240 defines a fork 248 with a pair of openings 249 on each side to support a pivot member 250. The pivot member 250 includes a body 252 with an opening configured to receive the blade connecting member 214 to mount the blade 200 on the assembly 220. A pivot pin 256 extends through the fork 248 and end of the pivot member body 250 such that the pivot member 250 is pivotally supported relative to the fork 248. A pair of opposed extensions 254 extend into the openings 249 and define the range of pivot. An adjustment screw 246 on the lateral adjustment arm 240 engages an opposite end of the pivot member 250 such that rotation thereof causes the pivot member 250, and thereby the blade 200, to pivot. Pivoting of the blade 200 allows the blade 200 to change angulation to compensate for various anatomy and tissue.
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 spirit and 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 and their equivalents. It is expressly intended, for example, that all ranges broadly recited in this document include within their scope all narrower ranges which fall within the broader ranges. It is also intended that the components of the various devices disclosed above may be combined or modified in any suitable configuration.
This patent application is a division of U.S. patent application Ser. No. 16/515,780, filed on Jul. 18, 2019, which is a continuation-in-part of U.S. patent application Ser. No. 16/205,892, filed on Nov. 30, 2018, which is a continuation application of U.S. patent application Ser. No. 15/954,655 filed on Apr. 17, 2018 which is a divisional of U.S. patent application Ser. No. 14/509,634, filed Oct. 8, 2014, which is a continuation-in-part of U.S. patent application Ser. No. 14/278,898 filed on May 15, 2014, the entire disclosures of which are incorporated herein by reference in their entireties for all purposes.