LATERAL MASS FIXATION IMPLANT
The various embodiments described herein provide lateral mass and facet fixation implants, which may be inserted and applied via a posterior approach, using minimally invasive or less invasive techniques. The embodiments described below generally include an intrafacet implant (or “facet implant”) and a lateral mass fixation member attached to or attachable to the facet implant. The lateral mass fixation member can include one or more tabs extending from a middle portion and configured to secure the lateral mass fixation member to lateral masses of adjacent vertebrae. The tabs may be flexible, semi-rigid, or rigid, and may be collapsible to facilitate insertion of the device. Methods for delivering the lateral mass and facet fixation implants are also described.
This application claims priority to U.S. Provisional Patent Application No. 62/003,443, entitled “Lateral Mass Fixation Implant,” filed on May 27, 2014. The full disclosure of the above-listed patent application is hereby incorporated by reference herein.
BACKGROUNDPosterior cervical fusion with lateral mass fixation is the most rigid cervical instrumentation. It requires extensive dissection of muscles and ligaments off the posterior spine, so that the surgeon can have direct visualization to safely perform the procedure. This dissection causes acute and chronic soft tissue pain syndrome. Acutely, patients are typically hospitalized for three to four days for pain control that requires IV narcotics. This is compared to one-day hospitalization for anterior approaches that do not require any muscle or soft tissue dissection. Long-term patients with posterior approaches frequently have persistent pain due to the extensive nature of the dissection. Sometimes, after posterior-access cervical fusion surgery, soft tissues may not return to anatomic position and may be permanently deformed. Persistent pain after posterior surgical approaches is referred to as post-laminectomy syndrome. (
Therefore, since it is considered less traumatic to the patient compared to posterior approaches, anterior cervical spinal fusion surgery has generally been preferred over posterior fusion surgery. At the same time, posterior approaches to the cervical spine do have some advantages over anterior approaches.
Lateral mass or pedicle screw fixation provides more rigid fixation of the cervical spine than anterior plates, interbody devices and interspinous wiring. It is best for traumatic instability, but it has also been used for degenerative conditions. Despite being the best fixation, lateral mass fixation is often avoided, because of the morbidity of the soft tissue dissection, as noted above. (
Starting a drill hole or inserting a screw into a lateral mass of a vertebra cannot currently be accomplished using a percutaneous approach. This is because soft tissue gets caught up in the drill, and the drill can skid off the bone and go out of control. Awls and firm pressure placed on bone with screws without direct visualization is dangerous in the posterior cervical spine, unless the surgeon has removed soft tissue and has direct visualization.
Therefore, it would be advantageous to have improved devices, systems and methods for performing cervical spinal fusion procedures via posterior access approaches. Ideally, these devices, systems and methods would allow for minimally invasive or less invasive access and fixation, as well as helping ensure proper placement of the fixation devices. At least some of these objectives will be met by the embodiments described herein.
BRIEF SUMMARYThe various embodiments described herein provide lateral mass and facet fixation implants, which may be inserted and applied via a posterior approach, using minimally invasive or less invasive techniques. The embodiments described below generally include an intrafacet implant (or “facet implant”) and a lateral mass fixation member attached to or attachable to the facet implant. The lateral mass fixation member can include one or more tabs extending from a middle portion and configured to secure the lateral mass fixation member to lateral masses of adjacent vertebrae. The tabs may be flexible, semi-rigid, or rigid, and may be collapsible to facilitate insertion of the member.
In one aspect, a spinal implant system is disclosed. The spinal implant system includes a facet implant member for positioning in a facet joint and a lateral mass fixation member attached to or attachable to the facet implant member. The facet implant member and the lateral mass fixation member may be two separate devices or components that are attachable in situ or they may be a single device or of a single piece or monolithic construction. In some embodiments, the facet implant member includes a peg and the lateral mass fixation member includes a hole formed therethrough for receiving the peg. The peg may have one of a round shape, a square shape, and a polygonal shape.
In some aspects, the lateral mass fixation member includes a plate, the plate including a middle portion, an opening in the middle portion configured to allow passage of a screw to connect the plate with the facet implant member, and two tabs extending from opposite sides of the middle portion to contact lateral masses of adjacent vertebrae. The tabs may include one or more surface features, such as spikes, extending from the tabs for securing the tabs to the lateral masses of adjacent vertebrae. The tabs may include one or more holes formed therethrough to receive one or more fixation devices configured to secure the tabs to the lateral masses of adjacent vertebrae. The tabs may extend from the sides of the middle portion via hinges and the tabs are rotatable about the hinges relative to the middle portion. The lateral mass fixation member may include two tabs that extend from the facet implant member to contact lateral masses of adjacent vertebrae. The tabs may be moveable from a collapsed configuration for delivery of the system into a patient to an expanded configuration for attachment to lateral masses of adjacent vertebrae.
In some aspects, the system may further include a guide member for guiding at least one of the facet implant member or the lateral mass fixation member to a spine for attachment thereto.
In some aspects, the lateral mass fixation member includes a first face configured to attach to the facet implant member, and a second face coupled to and forming an angle with the first face, wherein the second face is configured to secure the lateral mass fixation member to lateral masses of adjacent vertebrae.
In some aspects, the lateral mass fixation member includes an anchor including an attachment device for attaching to the facet implant and a rod receiving member. The fixation member further includes a rod having a length sufficient to contact lateral masses of adjacent vertebrae.
A method for implanting a spinal fixation implant is disclosed. The method includes inserting a facet implant member in a facet joint and attaching a lateral mass fixation member to the facet implant member. In some embodiments, attaching the lateral mass fixation member includes screwing the lateral mass fixation member to the facet implant member. The method may further include attaching a guide rod to the facet implant member, positioning the lateral fixation member adjacent to the facet implant via the guide rod, and removing the guide rod. In some embodiments, inserting the facet implant includes delivering the facet implant via a guide tube.
A method for implanting a spinal fixation implant is disclosed. In one aspect, the method includes inserting a facet implant member of a fixation system in a facet joint, and expanding a lateral mass fixation member of the fixation system to contact lateral masses of adjacent vertebrae. In some aspects, the method further includes attaching the lateral mass fixation member to the lateral masses using at least one screw.
These and other aspects and embodiments will be described in further detail below, in reference to the attached drawing figures.
The various embodiments described herein include a system for providing lateral mass fixation in the cervical spine, using posterior access, less invasive or minimally invasive, insertion methods. Generally, each system includes a facet component and a lateral mass fixation component. In some embodiments, the facet component and the lateral mass fixation component are separate devices until they are attached in situ within the patient. In other embodiments, the facet and lateral mass fixation components may be combined into one device. Some embodiments may include simply a facet implant by itself, which may be attached to one or more lateral mass fixation devices or members. Similarly, a lateral mass fixation device or member may be provided by itself, and may be compatible with one or more facet implant devices. The embodiments described herein also include methods for inserting, implanting and attaching the facet components and lateral fixation components described herein.
Lateral mass instrumentation may include a screw, staple or post in the lateral mass. Additional instrumentation such as a rod or plate may be used as a tension band to connect the rostral and caudal facet. This additional instrumentation may serve to limit flexion and extension as well as lateral bending. The facet implant connects with and/or helps guide the fixation member (or tension band) into place. The tension band device (e.g., plate, screw, rod or other material that bridges the rostral and caudal lateral mass) may be modular. It can be used to cross one or multiple motion segments. It may be put in before or after the facet implant. The combination of the facet implant and the lateral mass fixation member will provide superior fixation and stability of the joint in both the flexion and extension directions.
The surgeon may insert the facet implant though a minimal access incision, using an insertion system such as, but not limited to, the DTRAX® Spinal System, from Providence Medical Technology, Inc. (www.providencemt.com). A facet implant that may be used in the embodiments described herein includes the DTRAX® Cervical Cage, from Providence Medical Technology, Inc. (www.providencemt.com). The fixed point deep in the spine that is provided by the facet implant can be used to instrument the posterior cervical spine beyond the facet, from a percutaneous approach, without direct visualization. This avoids stripping all the soft tissue off the spine. A fixed point deep in the patient's spine prevents instruments from slipping off the spine and allows for location, alignment, and anchoring for fixation instrumentation. Also, the cervical facet has a fixed anatomic relationship to lateral mass bone consistent in all patients. Fixation instrumentation can be positioned off the facet implant to reliable landmarks on the lateral mass without direct visualization.
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All relative and directional references (including: upper, lower, upward, downward, left, right, leftward, rightward, top, bottom, side, above, below, front, middle, back, vertical, horizontal, and so forth) are given by way of example to aid the reader's understanding of the particular embodiments described herein. They should not be read to be requirements or limitations, particularly as to the position, orientation, or use unless specifically set forth in the claims. Connection references (e.g., attached, coupled, connected, joined, and the like) are to be construed broadly and may include intermediate members between a connection of elements and relative movement between elements. As such, connection references do not necessarily infer that two elements are directly connected and in fixed relation to each other, unless specifically set forth in the claims.
Although the invention has been disclosed in the context of certain embodiments and examples, the present invention extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the invention and obvious modifications and equivalents thereof. Thus, it is intended that the scope of the present invention herein disclosed should not be limited by the particular disclosed embodiments described above.
Claims
1. A spinal implant system, comprising:
- a facet implant member for positioning in a facet joint; and
- a lateral mass fixation member attached to or attachable to the facet implant member.
2. A system as in claim 1, wherein the facet implant member and the lateral mass fixation member are two separate devices that are attachable in situ.
3. A system as in claim 2, wherein the facet implant member comprises a peg and the lateral mass fixation member comprises a hole formed therethrough for receiving the peg.
4. A system as in claim 3, wherein the peg has one of a round shape, a square shape, and a polygonal shape.
5. A system as in claim 2, wherein the lateral mass fixation member comprises a plate, and wherein the plate comprises:
- a middle portion;
- an opening in the middle portion configured to allow passage of a screw to connect the plate with the facet implant member; and
- two tabs extending from opposite sides of the middle portion to contact lateral masses of adjacent vertebrae.
6. A system as in claim 5, wherein the tabs comprise one or more surface features extending from the tabs for securing the tabs to the lateral masses of adjacent vertebrae.
7. A system as in claim 5, wherein the tabs have one or more holes formed therethrough to receive one or more fixation devices configured to secure the tabs to the lateral masses of adjacent vertebrae.
8. A system as in claim 5, wherein the tabs extend from the sides of the middle portion via hinges and the tabs are rotatable about the hinges relative to the middle portion.
9. A system as in claim 1, wherein the facet implant member and the lateral mass member comprise one, attached device.
10. A system as in claim 9, wherein the lateral mass fixation member comprises two tabs that extend from the facet implant member to contact lateral masses of adjacent vertebrae.
11. A system as in claim 10, wherein the tabs are moveable from a collapsed configuration for delivery of the system into a patient to an expanded configuration for attachment to lateral masses of adjacent vertebrae.
12. A system as in claim 1, further comprising a guide member for guiding at least one of the facet implant member or the lateral mass fixation member to a spine for attachment thereto.
13. A system as in claim 1, wherein the lateral mass fixation member comprises:
- a first portion configured to attach to the facet implant member; and
- a second portion coupled to and forming an angle with the first portion, wherein the second portion is configured to secure the lateral mass fixation member to lateral masses of adjacent vertebrae.
14. A system as in claim 1, wherein the lateral mass fixation member comprises:
- an anchor including an attachment device for attaching to the facet implant and a rod receiving member; and
- a rod received in the anchor to secure the system to lateral masses of adjacent vertebrae.
15. A method for implanting a spinal fixation implant, the method comprising:
- inserting a facet implant member in a facet joint; and
- attaching a lateral mass fixation member to the facet implant member.
16. A method as in claim 15, wherein attaching the lateral mass fixation member comprises screwing the lateral mass fixation member to the facet implant member.
17. A method as in claim 16, further comprising:
- attaching a guide rod to the facet implant member;
- positioning the lateral fixation member adjacent to the facet implant via the guide rod; and
- removing the guide rod.
18. A method as in claim 15, wherein inserting the facet implant comprises delivering the facet implant via a guide tube.
19. A method for implanting a spinal fixation implant, the method comprising:
- inserting a facet implant member of a fixation system in a facet joint; and
- expanding a lateral mass fixation member of the fixation system to contact lateral masses of adjacent vertebrae.
20. A method as in claim 19, further comprising attached the lateral mass fixation member to the lateral masses using at least one screw.
Type: Application
Filed: May 27, 2015
Publication Date: Dec 3, 2015
Inventors: Bruce M. McCORMACK (San Francisco), Edward LIOU (Pleasanton, CA), Shigeru TANAKA (Half Moon Bay, CA), Christopher U. PHAN (Dublin, CA), Jeffrey D. SMITH (San Francisco, CA), Todd Sheppard SAUNDERS (Walnut Creek, CA), Krzysztof SIEMIONOW (Chicago, IL)
Application Number: 14/723,243