WO2019200368A1

WO2019200368A1 - Interfixated cervical stabilization system

Info

Publication number: WO2019200368A1
Application number: PCT/US2019/027415
Authority: WO
Inventors: Mir Haroon ALI
Original assignee: Ali Innovative Spine Solutions
Priority date: 2018-04-13
Filing date: 2019-04-13
Publication date: 2019-10-17

Abstract

A hybrid interfixated device for use in spinal surgery is disclosed herein. The device comprises a spacer body that may be interfixated between vertebrae into the disc space, wherein the spacer body comprises at least two fastener holes configured to receive intrinsic fasteners and a centering hole configured to receive a cervical plate using a plate-fastening fastener, and one or more intrinsic fasteners to secure the spacer body to the adjacent vertebrae. An anterior cervical plate may be affixed to the device at the centering hole using a plate-fastening fastener. Methods of stabilizing the cervical spine of a patient using the disclosed device are also disclosed herein. In a procedure that requires stabilizing multiple levels of the cervical spine, a hybrid interfixated device may be placed in each level requiring stabilization and an anterior cervical plate may or may not be fastened to each device.

Description

INTERFIXATED CERVICAL STABILIZATION SYSTEM

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and priority to U.S. Provisional Patent Application Serial No. 62/657,031, filed on April 13, 2018, the disclosure of which is incorporated herein in its entirety by reference.

BACKGROUND

Field of the Invention

The present disclosure relates to a novel interfixated cervical stabilization system, and methods of using the same.

Description of the Related Art

Technological advances in surgery have led to the use of surgical techniques that are less invasive and less disruptive than previously used surgical techniques, thereby reducing patient pain and facilitating faster recovery and return to function. For surgery involving the cervical spine, such as spinal fusion surgery, the use of interfixated devices has allowed for surgery to be performed in a less invasive manner, with less tissue disruption, lower profile fixation, and faster rates of fusion than prior generation spinal implants. Upon removal of the disc, an interfixated device is placed between adjacent vertebrae and secured to the vertebrae using intrinsic screws. These devices are generally made from titanium, on account of the known osseointegrative properties of titanium. Most currently available interfixated devices use three intrinsic screws to secure the device to the adjacent vertebrae, with one screw securing the device to one vertebra immediately adjacent to the device and two screws securing the device to the other vertebra immediately adjacent to the device on the opposite side. Interfixated devices that require only two screws, with one screw securing the device to one vertebra immediately adjacent to the device and a second screw securing the device to the other vertebra immediately adjacent to the device on the opposite side, have also recently become available. Such devices employ a locking mechanism to secure the screws to the adjacent vertebrae.

In certain difficult cases, fixation screws used in current interfixated devices are difficult to place, leading to a less secure implant and increased risk of damage to the patient’s vital organs in the neck, including the esophagus, trachea, and the carotid artery closest to the incision site. In addition, if a patient has severe osteoporosis, the fixation achieved by two or three interfixated screws may not be adequate, and thus additional fixation may be required or the patient may need to use an external brace post-surgery. The ability to integrate additional fixation or stability into current interfixated devices has not been established, and thus in such cases existing interfixated devices may not be feasible for use in the cervical spine surgery being performed.

Anterior cervical plating has also been used to stabilize the cervical spine. However, the use of anterior cervical plating presents inherent problems that render it generally less desirable than the use of interfixated devices. The prominence of the anterior cervical plate on the anterior cervical spine may, in rare but nonetheless clinically significant situations, cause problems with swallowing. Further, placement of the plate in proximity to the adjacent disc space and the additional dissection and exposure required to place the plate increases the risk of disc degeneration at the adjacent levels of the cervical spine. The ability to gauge the proper length of the plate and place the plate properly so that the adjacent segments are not compromised is a difficult task for even the most skilled and experienced spine surgeons.

In addition, when multiple levels of the spine are involved in a surgery, both existing interfixated devices and anterior cervical plating present problems when used. Interfixated devices are typically not used when multiple levels of the spine are involved, because it is difficult to place interfixated devices across multiple vertebrae and also to achieve the required stabilization using these devices. However, using anterior cervical plating is also challenging when multiple levels of the spine are involved, as it is necessary to align the curvature of the plate with the curvature of multiple vertebrae and additionally align spacers between the vertebrae. A typical technique for cervical spine surgery involving four levels of the spine involves use of a ten-hole anterior cervical plate and four spacers made from titanium, bone, or plastic. Achieving proper alignment of the anterior cervical plate in such a surgery is challenging for even the most skilled spine surgeons. In addition, the risk of swallowing problems and irritation of adjacent levels of the cervical spine increase as the number of levels of the spine involved in the surgery increases.

Thus there remains a need for an improved system for spine stabilization for use in spinal surgery that replicates the beneficial features of currently used systems without suffering from the drawbacks thereof. SUMMARY

A hybrid interfixated device for use in surgery involving the cervical spine, such as spinal fusion surgery, with one or more screws or other fasteners for intrinsic screw or other intrinsic fastener placement and a centering hole for the placement of a cervical plate that is secured with extrinsic screws or other fasteners, is disclosed herein. The hybrid interfixated device comprises a spacer body that may be interfixated between vertebrae into the disc space, wherein the spacer body comprises at least two fastener holes configured to receive intrinsic fasteners and a centering hole configured to receive a cervical plate using a plate-fastening fastener, and one or more intrinsic fasteners to secure the spacer body to the adjacent vertebrae. The fastener holes may preferably be threaded holes that are configured to receive screws, and the one or more intrinsic fasteners may preferably be screws.

A cervical plate may be affixed to the hybrid interfixated device at the centering hole using a plate-fastening screw or other plate-fastening fastener. The cervical plate may be selected based on the size of the spacer body and may preferably be attached to the device using the centering hole. Extrinsic screws or other fasteners may be placed into the vertebrae immediately above and below the disc space into which the spacer body is placed, and a plate- fastening screw or other plate-fastening fastener may also preferably secure the cervical plate to the spacer body. This may provide fixation that provides both adequate stabilization and is also less disruptive to surrounding tissues and reduces the risk to adjacent levels of the cervical spine. In addition, the use of an interfixated device as a primary stabilizer allows the use of a cervical plate with less of a three-dimensional profile than would be possible if a cervical plate were to be used exclusively. Methods of stabilizing the cervical spine of a patient using the disclosed hybrid interfixated device are also disclosed herein. In a procedure that requires stabilizing multiple levels of the cervical spine, a hybrid interfixated device may be placed in each level requiring stabilization. Each hybrid interfixated device may or may not be further stabilized by securing an anterior cervical plate. In some multi-level surgical procedures, it may be necessary or desirable to fasten an anterior cervical plate to each hybrid interfixated device. In other surgical procedures, it may be necessary or desirable to fasten an anterior cervical plate to one or more hybrid interfixated devices used in the procedure and not to fasten an anterior cervical plate to one or more other hybrid interfixated devices used in the procedure. Fastening an anterior cervical plate to a hybrid interfixated device allows the hybrid interfixated device to be secured to the spine of a patient using only one screw when necessary or desirable.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows an anterior view of a prior art anterior cervical plate.

Figure 2 shows an anterior view of a prior art interfixated device.

Figure 3 A shows an anterior view of an embodiment of the disclosed hybrid interfixated device.

Figure 3B shows a side view of the embodiment of the disclosed hybrid interfixated device shown in Figure 3.

Figure 4 shows an embodiment of the disclosed hybrid interfixated device with an anterior cervical plate comprising four fastener holes fastened thereto with a plate-fastening screw. Figure 5 shows an embodiment of the disclosed hybrid interfixated device with an anterior cervical plate comprising three fastener holes fastened thereto with a plate-fastening screw.

Figure 6 shows two hybrid interfixated devices placed into the two disc spaces between three adjacent vertebrae with a four-hole anterior cervical plate affixed to each hybrid interfixated device.

Figure 7 shows three hybrid interfixated devices placed into the three disc spaces between four adjacent vertebrae with a four-hole anterior cervical plate affixed to each hybrid interfixated device.

Figure 8 shows four hybrid interfixated devices placed into the four disc spaces between five adjacent vertebrae with a four-hole anterior cervical plate affixed to each hybrid interfixated device.

Figure 9 shows two hybrid interfixated devices placed into the two disc spaces between three adjacent vertebrae with a three-hole anterior cervical plate affixed to each hybrid interfixated device.

Figure 10 shows three hybrid interfixated devices placed into the three disc spaces between four adjacent vertebrae with a three-hole anterior cervical plate affixed to each hybrid interfixated device.

Figure 11 shows four hybrid interfixated devices placed into the four disc spaces between five adjacent vertebrae with a three-hole anterior cervical plate affixed to each hybrid interfixated device. PET ATT, ED DESCRIPTION OF TU I ILLUSTRATED EMBODIMENTS

The hybrid interfixated device provides the ability to place an interfixated device into position between adjacent vertebrae and an attempt for placement of intrinsic screws or other fasteners to secure the spacer body to the adjacent vertebrae.

The spacer body may preferably be substantially rectangular prismatic, with indentations for the fastener holes and centering hole. In some preferred embodiments, the six corners of the rectangular prism may be rounded. In some embodiments, the six edges of the rectangular prism may be rounded. In some embodiments, the six comers and the six edges of the rectangular prism may be rounded.

In some preferred embodiments, a first fastener hole may be angled upward at an approximately 45 degree angle to the plane orthogonal to the length of the spine and a second fastener hole may be angled downward at an approximately 45 degree angle to the plane orthogonal to the length of the spine and approximately orthogonal to the first fastener hole.

In some preferred embodiments, two intrinsic screws may be placed at an approximately 45 degree angle to the plane orthogonal to the length of the spine and may also preferably be placed approximately orthogonal to each other. A first intrinsic screw may preferably secure the spacer body to the vertebra immediately above the disc space where the spacer body is placed, and a second intrinsic screw may preferably secure the spacer body to the vertebra immediately below the disc space where the spacer body is placed.

The fasteners of the hybrid interfixated device may preferably be locked to prevent migration of the fasteners within the body of a patient after the hybrid interfixated device is placed into the patient’s spine. Locking the fasteners also prevents migration of the spacer body.

In some embodiments, the hybrid interfixated device may further comprise a fastener lock for each intrinsic fastener of the device. The fastener lock may prevent migration of its associated fastener. The fastener lock may comprise a ring with a directional lock that is akin to a one-way valve, a locking screw or nut placed on top of the fastener, or any other fastener locking system known in the art.

In some alternate embodiments, the fasteners may be locked in place via cold welding, torque limitation, or any other method disclosed in the art for locking fasteners used in interfixated devices that prevents migration of the intrinsic fasteners.

The hybrid interfixated device also provides an opportunity to provide additional or alternative fixation using a cervical plate. A cervical plate may be affixed to the hybrid interfixated device at the centering hole using a plate-fastening screw or other plate-fastening fastener. The cervical plate may be selected based on the size of the spacer body and may preferably be attached to the device using the centering hole. Extrinsic screws or other fasteners may be placed into the vertebrae immediately above and below the disc space into which the spacer body is placed, and a plate-fastening screw or other plate-fastening fastener may also preferably secure the cervical plate to the spacer body. This may provide fixation that provides both adequate stabilization and is also less disruptive to surrounding tissues and reduces the risk to adjacent levels of the cervical spine. In addition, the use of an interfixated device as a primary stabilizer allows the use of a cervical plate with less of a three-dimensional profile than would be possible if a cervical plate were to be used exclusively.

In some preferred embodiments, two upper extrinsic screws or other upper extrinsic fasteners may secure the cervical plate to the vertebra above the spacer body and two lower extrinsic screws or other lower extrinsic fasteners may secure the cervical plate to the vertebra below the spacer body. In other preferred embodiments, one upper extrinsic screw or other upper extrinsic fastener may secure the cervical plate to the vertebra above the spacer body and two lower extrinsic screws or other lower extrinsic fasteners may secure the cervical plate to the vertebra below the spacer body. In other preferred embodiments, two upper extrinsic screws or other upper extrinsic fasteners may secure the cervical plate to the vertebra above the spacer body and one lower extrinsic screw or other lower extrinsic fastener may secure the cervical plate to the vertebra below the spacer body.

In some preferred embodiments, the centering hole may be a threaded hole that is configured to receive a screw, such that a cervical plate may be screwed into the spacer body using a plate-fastening screw. In other embodiments, the centering hole may be configured to receive another type of fastener, such that a cervical plate may be fastened to the spacer body using said type of fastener.

The hybrid interfixated device preferably comprises titanium, to take advantage of the known osseointegrative properties of titanium. The cervical plate that may be used with the hybrid interfixated device also preferably comprises titanium. The screws or other fasteners of the hybrid interfixated device, the screws or other fasteners used to secure the cervical plate to the vertebrae, and the screw or other fastener used to secure the cervical plate to the hybrid interfixated device may also all preferably comprise titanium. In some preferred embodiments, the hybrid interfixated device, the cervical plate, all of the screws or other fasteners used to secure the cervical plate to the vertebrae, and the screw or other fastener used to secure the cervical plate to the hybrid interfixated device may preferably comprise titanium.

Figure 1 shows an anterior view of a prior art anterior cervical plate 100, including a plate body 101 and four threaded screw holes 102 that are configured to receive extrinsic screws.

Figure 2 shows an anterior view of a prior art interfixated device 200, including a spacer body 201, two intrinsic screws 203 for securing the interfixated device to the upper vertebra immediately adjacent to the spacer body, and one intrinsic screw 204 for securing the interfixated device to the lower vertebra immediately adjacent to the spacer body.

Figure 3 A shows an anterior view of an embodiment of the disclosed hybrid interfixated device 300, including a spacer body 301, an upper intrinsic screw 303 screwed into an upper fastener hole (not labeled) and into the vertebra immediately above the spacer body, a lower intrinsic screw 304 screwed into a lower fastener hole (not labeled) and into the vertebra immediately below the spacer body, and a threaded centering hole 305 configured to receive a plate-fastening screw.

Figure 3B shows a side view of the embodiment of the disclosed hybrid interfixated device 300 shown in Figure 3, including the spacer body 301, the upper intrinsic screw 303 screwed into the upper fastener hole (not labeled) and into the vertebra immediately above the spacer body, and the lower intrinsic screw 304 screwed into the lower fastener hole (not labeled) and into the vertebra immediately below the spacer body.

Figure 4 shows an embodiment of the disclosed hybrid interfixated device 400 with an anterior cervical plate 407 comprising four fastener holes fastened thereto with a plate-fastening screw 406. The plate 407 is configured to be secured to the vertebrae using four extrinsic screws.

Figure 5 shows an embodiment of the disclosed hybrid interfixated device 500 with an anterior cervical plate 507 comprising three fastener holes fastened thereto with a plate-fastening screw 506. The plate 507 is configured to be secured to the vertebrae using three extrinsic screws.

Methods of stabilizing the cervical spine of a patient using the disclosed hybrid interfixated device are also disclosed herein. In a procedure that requires stabilizing multiple levels of the cervical spine, a hybrid interfixated device may be placed in each level requiring stabilization. Each hybrid interfixated device may or may not be further stabilized by securing an anterior cervical plate. In some multi-level surgical procedures, it may be necessary or desirable to fasten an anterior cervical plate to each hybrid interfixated device. In other surgical procedures, it may be necessary or desirable to fasten an anterior cervical plate to one or more hybrid interfixated devices used in the procedure and not to fasten an anterior cervical plate to one or more other hybrid interfixated devices used in the procedure.

Fastening an anterior cervical plate to a hybrid interfixated device allows the hybrid interfixated device to be secured to the spine of a patient using only one screw. This may be advantageous in a situation where placement of a second screw is difficult or impossible due to anatomical or other considerations.

In some procedures, it may be difficult or impossible to place even one screw of the hybrid interfixated device into a vertebra adjacent to the disc space where the hybrid interfixated device is placed. In such cases, the spacer body may be placed into the disc space and an anterior cervical plate may be secured to the spacer body using a plate-fastening fastener, preferably a plate-fastening screw. The anterior cervical plate may then be secured to the vertebrae using extrinsic screws.

Figure 8 shows four hybrid interfixated devices placed into the four disc spaces between five adjacent vertebrae with a four-hole anterior cervical plate affixed to each hybrid interfixated device. Figure 9 shows two hybrid interfixated devices placed into the two disc spaces between three adjacent vertebrae with a three-hole anterior cervical plate affixed to each hybrid interfixated device.

Figure 11 shows four hybrid interfixated devices placed into the four disc spaces between five adjacent vertebrae with a three-hole anterior cervical plate affixed to each hybrid interfixated device.

The disclosed methods allow the use of separate hybrid interfixated devices for each level of a multi-level spinal stabilization or spinal fusion procedure, and thus complications related to placement of a single multi-level device, such as the great difficulty of achieving proper alignment of a single multi-level device, are greatly ameliorated.

The disclosed device and methods generate increasing benefits as additional cervical levels are involved in a procedure. Thus use of the disclosed hybrid interfixated device will provide significant advantages in three-level and four-level cervical spinal procedures.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention disclosed herein. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

All references cited herein are expressly incorporated by reference.

Claims

CLAIMS What is claimed is:

1. A hybrid interfixated device for use in securing the cervical spine comprising:

a. a spacer body that may be interfixated between vertebrae into the disc space and

b. one or more intrinsic fasteners suitable for securing the spacer body to the adjacent vertebrae;

wherein the spacer body comprises at least two fastener holes configured to receive intrinsic fasteners and a centering hole configured to receive an anterior cervical plate using a plate-fastening fastener.

2. The device of Claim 1, wherein the device comprises titanium.

3. The device of Claim 1, wherein the spacer body comprises exactly two fastener holes.

4. The device of Claim 3, wherein a first fastener hole is angled upward at an approximately 45 degree angle to the plane orthogonal to the length of the spine and a second fastener hole is angled downward at an approximately 45 degree angle to the plane orthogonal to the length of the spine and approximately orthogonal to the first fastener hole

5. The device of Claim 4, wherein the fastener holes are threaded holes configured to receive screws.

6. The device of Claim 5, wherein the one or more intrinsic fasteners are titanium screws.

7. The device of Claim 1, wherein the spacer body is substantially rectangular prismatic and further comprises indentations for the fastener holes and the centering hole.

8. The device of Claim 7, wherein the six corners of the substantially rectangular prismatic spacer body are rounded.

9. The device of Claim 6, wherein the spacer body is substantially rectangular prismatic and further comprises indentations for the fastener holes and the centering hole.

10. The device of Claim 9, wherein the six corners of the substantially rectangular prismatic spacer body are rounded.

11. The device of Claim 6, further comprising one or more fastener locks, wherein each of the one or more intrinsic fasteners is locked using a fastener lock.

12. The device of Claim 6, wherein each of the intrinsic screws is configured to be locked without the use of a fastener lock.

13. The device of Claim 6, wherein the centering hole is a threaded hole that is configured to receive a plate-fastening screw.

14. A method of stabilizing the cervical spine of a patient comprising placing the hybrid interfixated device of Claim 1 into the disc space between cervical vertebrae of the patient.

15. The method of Claim 14, further comprising securing an anterior cervical plate to the hybrid interfixated device of Claim 1 using a plate-fastening screw.

16. The method of Claim 15, wherein the plate is a four-hole anterior cervical plate and wherein the plate is secured to the cervical vertebrae of a patient using four extrinsic screws.

17. The method of Claim 15, wherein the plate is a three-hole anterior cervical plate and wherein the plate is secured to the cervical vertebrae of a patient using three extrinsic screws.

18. A method of stabilizing multiple levels of the cervical spine of a patient comprising placing a hybrid interfixated device of Claim 1 into the disc space between each of two or more sets of two adjacent cervical vertebrae of the patient.

19. A method of stabilizing three levels of the cervical spine of a patient comprising placing a hybrid interfixated device of Claim 1 into the disc space between each of three sets of two adjacent cervical vertebrae of the patient.

20. A method of stabilizing four levels of the cervical spine of a patient comprising placing a hybrid interfixated device of Claim 1 into the disc space between each of four sets of two adjacent cervical vertebrae of the patient.