The present invention relates to the field of spinal fusion fixation devices. More particularly, the invention relates to a spinal fusion clamp implant that connects a first vertebra (e.g., the C1 vertebra) with a second vertebra (e.g., the C2 vertebra).
The first and second cervical spine vertebrae (C1 and C2) are unique due to the presence of a synovial “pin joint” (referred to as the atlantoaxial joint), compared to the intervertebral discs in the lower cervical spine. As shown in
Posterior spinal fusion, in which an implant construct is used to hold adjacent vertebrae together until they heal into a single piece of solid bone, has become the most common surgical treatment for type II odontoid fractures in elderly patients when surgery is feasible. Since being introduced in 2001, the Harms construct has become the standard fixation for posterior fusion of the atlantoaxial segment due to good construct stability and high fusion rates.
Attempts have been made both clinically and experimentally to develop new constructs and surgical techniques that better suit the needs of the C1/C2 segment. For example, Huang et al. (Posterior atlantoaxial fixation: a review of all techniques, The Spine Journal, Vol. 15, 2015, pp. 2271-2281) discusses, inter alia, various C1-C2 atlantoaxial stabilization/fixation techniques involving screws and clamps or hooks, such as C1-C2 apofix clamps, C1 hook combined with a C2 pedicle screw, and a C1 screw combined with C2 hooks. However, these techniques are not sufficiently stable (e.g., clamp slippage occurs frequently), result in pseudarthrosis, and/or are generally difficult to use in surgery. On the other hand, as shown in the posterior and lateral views of
It is therefore desirable to provide a spinal fusion fixation device that does not suffer from the above drawbacks.
Advantages of the present invention will become more fully apparent from the detailed description of the invention below.
The present invention in the various embodiments described below addresses the problems discussed above and other problems, by providing a spinal fusion clamp implant that connects a first vertebra with a second vertebra. The clamp implant includes a clamp assembly that connects to the first vertebra. The clamp assembly includes a superior jaw assembly having at least one superior jaw, and includes an inferior jaw assembly having at least one inferior jaw. The superior jaw and inferior jaw are opposedly arranged and clamp onto the first vertebra. The clamp implant also includes an implant assembly that connects to the second vertebra, and a connection system that connects the clamp assembly with the implant assembly. In a preferred embodiment, the first vertebra is the C1 vertebra, and the superior jaw and inferior jaw clamp onto the posterior arch of the C1 vertebra.
The present invention advantageously reduces the invasiveness of atlantoaxial posterior fusion surgeries by providing a clamp implant to replace C1 lateral mass screws and instead affix to the posterior arch of C1. Additional embodiments and additional features of embodiments for the clamp implant are described below and are hereby incorporated into this section.
The features, objects, and advantages of the present disclosure will become more apparent from the detailed description set forth below when taken in conjunction with the drawings in which like reference characters identify correspondingly throughout and wherein:
In the following detailed description, reference is made to certain embodiments. This detailed description is merely intended to teach a person of skill in the art further details for practicing preferred aspects of the present teachings and is not intended to limit the scope of the claims. Therefore, combinations of features disclosed in the following detailed description may not be necessary to practice the teachings in the broadest sense, and are instead taught merely to describe particularly representative examples of the present teachings. It is to be understood that other embodiments may be employed and that various structural changes may be made.
With reference to
Clamp assembly 110 comprises a superior jaw assembly 115 of two superior jaws 115a, and an inferior jaw assembly 116 of two inferior jaws 116a. The superior jaws 115a and the inferior jaws 116a are opposedly arranged and are configured to clamp onto the posterior arch 8 of the C1 vertebra 6. The jaws of the clamp are concave in shape to conform to the superior and inferior sides of the C1 posterior arch. The fixation surface of the inferior jaw 116a is designed with less concavity (i.e., greater radius of curvature) than the superior jaw 115a, since the inferior side of the C1 posterior arch is generally flatter than the superior side. In different implant variations, the concavity of the inferior and superior jaws may be the same. Alternatively, the inferior and superior jaws may also be designed to have no concavity (i.e, be flat) or may even be designed to have a variety of convex shapes.
As shown in
To avoid injury to the vertebral artery 22 (which sits atop the vertebral groove 23), the lateral footprint distance L1 of the superior jaws 115a is less than the lateral footprint distance L2 of the inferior jaws 116a. Injury to the vertebral artery 22 is not a concern for the inferior jaws 116a, so the L2 dimension can be larger to provide additional component stiffness which increases overall implant stability. In different implant variations, the L1 and L2 dimensions could vary, and L1 may not be smaller than L2.
As further shown in
As shown in
As shown in the anterior view of
The superior jaw assembly 115 further includes jaw locking screws 146 (see
Alternatively or additionally, in a likewise manner to that described above, the two inferior jaws 116a may be designed so they are capable of independent movement from each other. Thus, the inferior jaw assembly 116 may comprise a (linear) single axial joint (not shown) similar to single axial joint 131 associated with the inferior jaws 116a, or a ball joint (not shown), similar to ball joint 133 associated with the inferior jaws 116a. The inferior jaw assembly 116 would then further comprise jaw locking screws (not shown), similar to jaw locking screws 146, for locking the inferior jaws 116a in place.
As described in further detail below, an implant assembly, such as C2 translaminar screws 26 or pedicle screws 28, is configured to be implanted into translaminar portions or pedicle portions of the C2 vertebra (see
Connection system 150 comprises a polyaxial connection system comprising a polyaxial rod 155 with a spherical head 156, and a rod cap screw 161 configured to be tightened to apply pressure to the spherical head 156, thereby locking the polyaxial rod 155 in place. More specifically, once the clamp 110 has been locked into place on the C1 posterior arch 8, rods 155 are inserted into the clamp to connect the clamp 110 to the implant used in C2, thus creating the overall clamp implant fusion construct. The use of C2 pedicle screws 28 and/or C2 translaminar screws 26 has been previously discussed as feasible implant components that could be used in conjunction with the C1 clamp 110. However, the C1 clamp 110 can be used with any C2 implant component designed to be connected to the C1 implant component through the use of rods. As shown in FIG. 8A, the rods for the C1 clamp (referred to as polyaxial rods 155) have spherical heads so that, prior to tightening of the rod cap screw 161, they can articulate within the polyaxial sockets 158 of the C1 clamp body. The sockets, shown in
Once both rods 155 are placed in the sockets 158, they can be connected to the C2 implant assembly, such as C2 translaminar screws 26 (
The clamp implant of the present invention can also be modified for a multi-level fusion that includes the occipital (C0) vertebra. In this case, the rod cap screws 161 are replaced with rod cap screws that also have polyaxial fixation heads 170 (
The clamp implant of the present invention is manufactured from a biocompatible material such as pure titanium, titanium alloy, stainless steel or cobalt chromium alloy or a material with potential for bone ongrowth/ingrowth such as porous tantalum. Alternatively, or additionally, porous surfaces with or without coatings such as hydroxyapatite or hydroxyapatite with tricalcium phosphate can be used on parts of the implant to bioactively encourage bone ongrowth/ingrowth. Some parts of the clamp implant of the present invention can also be made from a polymer such as PEEK or a polymer composite such as carbon fiber reinforced PEEK. Ceramic inserts can be used for some of the bearing surfaces.
The instrumentation 1000 used in conjunction with the implant, shown in
The clamp implant of the present invention can be provided in a variety of sizes to cater to the anatomy of the entire patient population. Three-dimensional printing may be used to fabricate any or all of the components in the manufacture of the clamp implant. Three-dimensional printing may also be used to introduce porosity or a lattice structure to encourage bone ingrowth/ongrowth.
Although embodiments are described above with reference to a clamp implant comprising a clamp assembly that, for example, clamps onto the posterior arch of C1, the jaw assemblies of the clamp assembly described in any of the above embodiments may alternatively clamp onto other portions of C1 or other vertebra. Such alternatives are considered to be within the spirit and scope of the present invention, and may therefore utilize the advantages of the configurations and embodiments described above.
In addition, although embodiments are described above with reference to a clamp implant comprising an implant assembly (e.g., for C2), the implant assembly described in any of the above embodiments may alternatively be replaced with a secondary clamp assembly (e.g., of the types used for C1 described above). The jaw assemblies for this secondary clamp assembly may clamp onto any portion of the C2 or other vertebra. Such alternatives are considered to be within the spirit and scope of the present invention, and may therefore utilize the advantages of the configurations and embodiments described above.
The above description and drawings are only to be considered illustrative of specific embodiments, which achieve the features and advantages described herein. Modifications and substitutions to specific process conditions may be made. Accordingly, the embodiments of the invention are not considered as being limited by the foregoing description and drawings.
More generally, even though the present disclosure and exemplary embodiments are described above with reference to the examples according to the accompanying drawings, it is to be understood that they are not restricted thereto. Rather, it is apparent to those skilled in the art that the disclosed embodiments can be modified in many ways without departing from the scope of the disclosure herein. Moreover, the terms and descriptions used herein are set forth by way of illustration only and are not meant as limitations. Those skilled in the art will recognize that many variations are possible within the spirit and scope of the disclosure as defined in the following claims, and their equivalents, in which all terms are to be understood in their broadest possible sense unless otherwise indicated.
This is a continuation of U.S. patent application Ser. No. 16/010,626, filed Jun. 18, 2018, which claims priority from U.S. Provisional Application No. 62/522,452, filed on Jun. 20, 2017, and U.S. Provisional Application No. 62/645,520, filed on Mar. 20, 2018, the disclosures of which are hereby incorporated herein by reference in their entireties.
Number | Name | Date | Kind |
---|---|---|---|
4611582 | Duff | Sep 1986 | A |
4901964 | McConnell | Feb 1990 | A |
5074864 | Cozad et al. | Dec 1991 | A |
5360429 | Jeanson et al. | Nov 1994 | A |
5415659 | Lee et al. | May 1995 | A |
5437669 | Yuan | Aug 1995 | A |
5540688 | Navas | Jul 1996 | A |
5620444 | Assaker | Apr 1997 | A |
5928232 | Howland | Jul 1999 | A |
6458131 | Ray | Oct 2002 | B1 |
7686833 | Muhanna et al. | Mar 2010 | B1 |
8790380 | Buttermann | Jul 2014 | B2 |
8870926 | Kumar | Oct 2014 | B2 |
9107717 | Henderson, Sr. et al. | Aug 2015 | B2 |
9204908 | Buttermann | Dec 2015 | B2 |
9775650 | Buttermann | Oct 2017 | B2 |
20030080267 | Eslick | May 2003 | A1 |
20040087948 | Suddaby | May 2004 | A1 |
20060241591 | Biscup | Oct 2006 | A1 |
20070233091 | Naifeh et al. | Oct 2007 | A1 |
20080103512 | Gately | May 2008 | A1 |
20080114401 | Liu | May 2008 | A1 |
20080281423 | Sheffer | Nov 2008 | A1 |
20090018584 | Henderson, Sr. | Jan 2009 | A1 |
20090163920 | Hochschuler et al. | Jun 2009 | A1 |
20110137353 | Buttermann | Jun 2011 | A1 |
20110178552 | Biscup | Jul 2011 | A1 |
20120265204 | Schmierer | Oct 2012 | A1 |
20130090692 | Nuckley | Apr 2013 | A1 |
20130231704 | Larroque-Lahitette | Sep 2013 | A1 |
20130274808 | Larroque-Lahitette | Oct 2013 | A1 |
20140214083 | Refai | Jul 2014 | A1 |
20150196328 | Hirschl | Jul 2015 | A1 |
20160015430 | Buttermann | Jan 2016 | A1 |
20160095632 | Faulhaber | Apr 2016 | A1 |
20160183981 | Schlaepfer | Jun 2016 | A1 |
20170303970 | Puryear | Oct 2017 | A1 |
20170319238 | Boehm, Jr. | Nov 2017 | A1 |
20180008321 | Stern | Jan 2018 | A1 |
20180289397 | Buttermann | Oct 2018 | A1 |
Entry |
---|
D-G Huang et al., “Posterior atlantoaxial fixation: a review of all techniques,” The Spine Journal, vol. 15, pp. 2271-2281 (2015). |
I. Dorward et al., “Seven Years of Experience With C2 Translaminar Screw Fixation: Clinical Series and Review of the Literature,” Neurosurgery, vol. 68, No. 6, pp. 1491-1499 (Jun. 2011). |
Olerud, “The C1 claw device: a new instrument for C1-C2 fusion,” Eur. Spine J., vol. 10, pp. 345-347 (2001). |
S.S Kale, “C1 C2 Fusion and Indication Technique and Complication,” (2013). |
J. Harms, “Posterior C1 C2 Fusion with Polyaxial Screw and Rod Fixation.” Spine, vol. 26, No. 2, pp. 2467-2471 (2001). |
S. Siasios, “C1-C2 Posterior Cervical Fixation by a Harms Technique Modification,” J. Spinal Furg. 2017, vol. 4, No. 1, pp. 14-18. |
Number | Date | Country | |
---|---|---|---|
20200214744 A1 | Jul 2020 | US |
Number | Date | Country | |
---|---|---|---|
62645520 | Mar 2018 | US | |
62522452 | Jun 2017 | US |
Number | Date | Country | |
---|---|---|---|
Parent | 16010626 | Jun 2018 | US |
Child | 16821525 | US |