LATERAL MASS FIXATION SYSTEM
A device for accessing and guiding at least one fixation device to a spine may include a distal portion configured to fit in a facet of the spine and a proximal portion extending from the distal portion. The proximal portion may be detachable from the distal portion and may be hollow or solid. A system for accessing and guiding at least one fixation device to a spine may include a distal portion configured to fit in a facet of the spine, a proximal portion extending from the distal portion, and a slidable guide device for sliding over the facet guide device to guide at least one instrument to the spine.
This application claims priority to U.S. Provisional Patent Application No. 62/004,143, entitled “Lateral Mass Fixation System,” filed on May 28, 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 devices, systems and methods for accessing the cervical spine via a posterior approach and implanting a spinal fixation device in the cervical spine. The embodiments described below generally include a guide device, through which or along which one or more spinal fixation devices may be advanced. The guide devices described herein generally include a distal end that can be inserted into a cervical facet. Once inserted into a facet, the guide device is relatively stabilized (or “docked”) on the spine and thus can be used as a point of stabilization.
A device for accessing and guiding at least one fixation device to a spine is disclosed. In some aspects, the device includes a distal portion configured to fit in a facet of the spine and a proximal portion extending from the distal portion. In various embodiments, the distal and proximal portions are hollow. In some embodiments, the distal and proximal portions are solid. The distal portion may be removable from the proximal portion. In some embodiments, the distal portion includes a chamfered or beveled end portion configured to facilitate insertion of the distal portion in the facet of the spine. The proximal portion may include a slot formed therethrough for receiving and advancing a fixation device to the spine. The end of the proximal portion may include opposing sides having a concave shape and/or opposing sides having a convex shape.
A system for accessing and guiding at least one fixation device to a spine is disclosed. In one aspect, the system includes a facet guide device, the facet guide device including a distal portion configured to fit in a facet of the spine and a proximal portion extending from the distal portion. The system further includes a slidable guide device for sliding over the facet guide device to guide at least one instrument to the spine. The slidable guide device may be rotatable about a longitudinal axis of the facet guide device. The instrument may be a decortication device. The slidable guide device may be a double-barreled or dual-lumen guide tube. The slidable guide device may further include a drill guide having at least one drill path defined therein. The proximal portion of the facet guide device may have one of a circular cross-sectional shape or a square cross-sectional shape. The proximal portion of the facet guide device may have opposing sides having a concave shape. The proximal portion of the facet guide device may have opposing sides having a convex shape. The slidable guide device may include a first tube for sliding over the proximal portion of the facet guide device and a second tube mounted on a side of the first tube for guiding the at least one instrument. The system may further include at least one bone screw for advancing through the slideable guide device.
A method for implanting a spinal fixation implant is disclosed. The method includes advancing a guide device into a facet between two adjacent vertebrae, advancing a fixation device along the guide device, and attaching the fixation device to at least one of the two adjacent vertebrae. The method may further include attaching the fixation device by one of attaching a plate to a facet implant located in the facet or attaching a plate to the two adjacent vertebrae.
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 provide devices, systems and methods for accessing the cervical spine via a posterior approach and implanting a spinal fixation device in the cervical spine. The embodiments allow for a posterior approach using minimally invasive or less invasive techniques. The embodiments described below generally include a guide tool, through which or along which one or more spinal fixation devices may be advanced.
The surgeon may advance the guide tool into the facet from outside the patient though a minimally invasive or less invasive incision, and then may hold the guide tool via a handle or proximal end residing outside the patient. This fixed point deep in the spine can be used to advance drills, awls, plates, rods and screws, to instrument the posterior cervical spine other than 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 or drills catching soft tissue and skidding out of control. Also, the cervical facet has a fixed anatomic relationship to lateral mass bone consistent in all patients. Instruments can be advanced over the facet tool to reliable landmarks on the lateral mass without direct visualization.
Some of the devices, systems and methods described herein may include, be performed using, or be similar to one or more components of the DTRAX® Spinal System, from Providence Medical Technology, Inc. (www.providencemt.com). Various components of the DTRAX® Spinal System may be modified or adjusted, according to various embodiments, for uses described herein.
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The C7 and T1 and T2 facets have a fixed relationship to the pedicle. All of the above devices, systems and methods may be used to cannulate the pedicle percutaneously, similar to that described for the lateral mass.
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
1-20. (canceled)
21. An assembly for accessing a facet joint between a first vertebra and a second vertebra adjacent said first vertebra, said assembly comprising:
- a facet access portion comprising: a proximal elongated body portion comprising a first central longitudinal axis, and at least one distal blade portion configured for insertion into said facet joint; and
- a guide portion defining at least a first lumen, wherein said first lumen comprises a second central, longitudinal axis,
- wherein said first and second central longitudinal axes are distinct and parallel, and wherein said first lumen of said guide portion provides access to a posterior portion of one of the first vertebra and the second vertebra, and further wherein the first lumen of the guide portion is configured to receive and guide at least one instrument to said posterior portion.
22. The assembly of claim 21, wherein the at least one instrument comprises one of a drill, a rasp and a decorticator.
23. The assembly of claim 21, wherein said at least one distal blade portion extends distally beyond a distal end of said first lumen.
24. The assembly of claim 21, wherein the guide portion further comprises a second lumen, and further wherein said second lumen is adapted to receive the proximal elongated body portion of said facet access portion such that said at least one distal blade portion also extends distally beyond a distal end of said second lumen.
25. The assembly of claim 21, wherein the posterior portion consists of a portion of a lateral mass of said first vertebra or second vertebra.
26. The assembly of claim 21, wherein the facet joint is a cervical facet joint.
27. A method for accessing a facet joint between a first vertebra and a second vertebra adjacent said first vertebra, said method comprising:
- accessing said facet joint from a posterior approach with a facet access portion of an assembly, the facet access portion comprising a proximal elongated body portion comprising a first central longitudinal axis, and at least one distal blade portion configured for insertion into said facet joint;
- positioning said at least one distal blade portion into said facet joint;
- accessing a posterior portion of one of the first vertebra and the second vertebra with a guide portion of said assembly, said guide portion defining at least a first lumen, wherein said first lumen comprises a second central, longitudinal axis that is distinct from and parallel to said first central longitudinal axis; and
- introducing at least one instrument through said first lumen to access said posterior portion.
28. The method of claim 27, wherein said at least one instrument is a drill, said method further comprising forming a hole in said posterior portion using the drill.
29. The method of claim 28, wherein said posterior portion is a lateral mass of one of the first vertebra and second vertebra.
30. The method of claim 29, wherein said facet joint is a cervical facet joint.
31. The method of claim 27, wherein the guide portion further comprises a second lumen, said second lumen comprising a third central longitudinal axis.
32. The method of claim 31, wherein the second longitudinal axis of the at least one lumen and said third longitudinal axis of said second lumen are distinct and parallel.
33. The method of claim 31, wherein at least one of the first and second lumens is configured to receive the elongated body portion of said facet access portion.
34. The method of claim 33, wherein the facet access portion comprises a chisel.
35. The method of claim 27, wherein said accessing a posterior portion of one of the first vertebra and second vertebra comprises accessing a superior lateral mass of the facet joint.
36. The method of claim 27, wherein said accessing a posterior portion of one of the first vertebra and second vertebra comprises accessing an inferior lateral mass of the facet joint.
37. The method of claim 28, further comprising removing the drill from the first lumen and delivering a fixation device into said hole.
38. The method of claim 37, wherein said fixation device comprises at least one bone screw.
39. The method of claim 27, wherein said facet joint is a cervical facet joint, and said posterior portion is a lateral mass of the first vertebra or second vertebra.
Type: Application
Filed: Dec 29, 2022
Publication Date: May 4, 2023
Inventors: Bruce M. McCormack (San Francisco, CA), Edward Liou (Pleasanton, CA), Shigeru Tanaka (Half Moon Bay, CA), Christopher U. Phan (Dublin, CA)
Application Number: 18/090,640