Patent Application
20170296239
This application and device have received no federally sponsored research or development assistance.
U.S. Classification 606/902, 29/592
Spondylolysis, is a condition in which a crack or fracture occurs in the posterior lateral section(s) of vertebrae of a patient's spinal column or the pars interarticularis. This spondylolysis stress fracture, commonly referred to as a pars fracture normally occurs in children and adolescents, most commonly with those who participate in activities involving repetitive motions with extension. It additionally, a pars fracture may occur in patients involved in an extension trauma event. The fracture may occur on one or both sides of a vertebra and may occur along multiple vertebrae. Current treatments are only partially effective, and many patients will experience continual low back pain, limited return to sports, and other complications throughout adulthood.
Existing initial treatments may consist of nonsteroidal anti-inflammatory medications, steroid injections, physiotherapy, bracing, and activity modification. If persistent pain after non-operative treatment continues, surgery may be required. One of the more typical operations that may be performed includes a laminectomy to remove a portion of the vertebra, including the pars fracture. This will decompress the nerve roots, resulting in short term relief, yet will destabilize the spine, likely resulting in further surgeries. A second and more common option occurring after cascading co-morbidities, includes a posterior lumbar fusion. A posterior lumbar fusion involves fusing two or more adjacent vertebral bodies, including the pars defect. This surgery will prevent further trauma to the pars defect, but will unfortunately render the operative location motionless and likely result in cascading revision surgeries for the adolescent throughout adulthood.
Other less common surgical means include fracture reduction with facet or trauma screws as well as with wires and cables. These have seen some clinical success but have not become common treatment options. For younger patients, this is not an option as there is insufficient bone for internal screw placement.
The presented invention will allow for improved surgical devices, specifically for these young patients, to allow them an opportunity for an improved physical and emotional future with a more advanced clinical fracture repair devices. Direct repair of a pars defect will allow for restoration of normal anatomy of the posterior elements, preservation of the functional motion segment, less surgical trauma with dissection restricted only lateral to the spinous process, less blood loss, and early functional recovery. The device is removable after fusion to allow for normal spinal growth after fracture repair.
As expanded indications for the device, adult and elder patients with pars fractures and instability may be treated with the device per the presented benefits.
Other means for pars fraction repair devices have been disclosed in prior art. For example, first reference, U.S. Pat. No. 7,883,532, to Robert Biscup, titled Vertebral pars interarticularis clamp a new spine fixation device, instrumentation, and methodology, refers to a hub and first and second arm connected and movable to at least partially and telescopically clamp to the lamina across a pars fracture to secure the pars fracture. The device generally traverses parallel to the pars fracture and is generally non-conforming to the anatomy. It does not compress across or perpendicular to the fracture.
A second reference, U.S. Published Pending patent application Ser. No. 13/438,912, to Carl Pasquale Giordano, titled Plates configured to rigidly fix fragments of a pars interarticularis to one another, discloses a generally contouring outer member secured to a pedicle by means of a pedicle screw that nests within the contour. The contour is open to allow for bone graft placement to the pars fracture and is generally conforming to the lamina and pedicle. The contour is secured to the lamina, inferior to the fracture, with small threaded fixation screws. This device does not teach fracture compression and relies on small bone screws to affix the device to the lamina. The pedicle screw placement presents a trajectory that may require partial removal and therefor destabilization of the adjacent facet joint while the pedicle of an adolescent may not be of sufficient geometric proportions to accept a pedicel screw.
A third reference, U.S. Published Pending patent application Ser. No. 12/561,141, to Dimitriy G. Kondrashov, titled System and method to stablize a spinal column including a spinolaminar locking plate, includes a contoured lamaina plate with threaded holes that guides and fixates threaded screws that first penetrate the spinous process, second penetrate across a facet capsule adapted to penetrate an articular process of the targeted vertebra and the mating articular process of a vertebra above the targeted vertebra to resist motion at the facet joint, and third to penetrate a pedicle or lamina. The screws additionally nest within the contoured plate. The screws are taught to penetrate across anatomical joints to fuse adjacent vertebral bodies. The Kondrashov application includes anteriorly protruding features used to stabilize the plate's placement during surgery but which do not teach a snap fit or conforming condition to the anatomy for post-surgical stabilization and which do not wrap to the anterior aspect of the lamina.
A fourth reference, U.S. Pat. No. 4,257,409, to Kazimierz Bacal, titled Device for treatment of spinal curvature, discloses hook features that wrap around to the anterior aspect of the lamina along either the superior or inferior edges of the lamina. The hook features are generally parallel to the anterior hook feature and contain constant radii, straight slopes, and parallel features that exist as straight extrusion cuts perpendicular to a single plane.
This device is intended for orthopedic applications, particularly to treat a pars interarticularis fracture. The device is highly specialized to treat a common pars fracture with a uniquely contoured device that stabilizes the inferior fractured element with a generally conforming and non-linear hooked surface then transcribing the pars fracture to rigidly attach to the cortical bone between the facet and pedicle bones while applying compression across the fraction for fracture healing and stabilization.
A novel device and method for fracture fixation of a defect seen within the pars interarticularis (pars) is disclosed.
There are three key advanced technologies, that when used in collaboration, have allowed the invention the ability to treat pars fractures with a highly focused device and method. These include more accurate computer tomography and magnetic resonance scans and datasets, 3-D computational reconstructions, and additive manufacturing. The more accurate imaging systems have allowed for a proper diagnosis and cataloging of the defect. The 3-D computational reconstructions have allowed for the system to be created around common anatomical fractures while offering more specific geometries of less common anatomical pathologies. Additive manufacturing (titanium DMLS) has allowed for a cost effective means to commercialize the pars fracture repair plates per the complex geometry. Additive manufacturing of metals such as titanium and stainless, plastics such as PEEK and PEAK, restorable polymers, and collagen, or including any combination thereof are included within the scope of this invention. Traditional subtractive manufacturing, molding, and forming is additionally included within the scope of this invention. Post treatments such as tumbling, polishing, anodizing, cryo-deburr, HA surface treatments, and nano surfaces may further be included.
The physical devices disclosed are fusion plates forming a more complex and non-linear mating surface profile as required to match the defect zone. A novel feature of this invention is that the plate will additionally wrap around the boney structures sufficiently to stabilize the fracture without the placement of secondary bone screws. However this secondary bone screw will allow for further stabilization to the lamina as well as to allow for secondary device attachment, such as to a rod, tulip head, connector, or other means. The primary bone screw as later disclosed, acts across the fracture in a generally perpendicular manner as to present at least a partial force vector to compress the presented fracture, without protruding into or in a manner locking or restricting motion of a facet capsule. Partial motion restrictions, depending on patient anatomy and final device placement, may be restricted as part of post-surgical management or until the device is removed once the fracture has healed.
The preferred embodiment of the plate being disclosed is designed to interact with features of a vetebral body 1 shown in
Referring
The plate also contains a single second screw location 10 positioned across or in proximity to the fracture with a trajectory between the superior 4 and inferior 5 articular processes for plate securement on the opposite side of the fracture.
Pockets or features 12 of varying shape or porosity on the inferior surface 11 of the plate to induce osteoconduction or for which to secure the graft material such as but not limited to autograft, allograft, BMP, etc., creating a more secure bond between the plate 7, vertebral lamina 2 and across the fracture 6. The plate 7 also has a hook feature 15 which will engage the inferior edge 3 of the lamina.
Of additional importance to the hook feature 15 is that is flairs outward as it travels lateral 13. If the cortical screw 16 is placed last, the hook feature will tighten against the boney anatomy as the lag screw 17 is tightened, pulling the plate across the fracture and slightly lateral into a tighter seating position.
A similar flaring will be taught on the medial hook aspect 22, as shown in
Referring to
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Provisional Application No. 62/127,174 Under the benefit of 37 CFR 1.78, a petition to grant the filing date benefit of provisional application 62/127,174 filed on 2 Mar. 2015 is hereby respectively submitted. The delay in filing the nonprovisional application was unintentional and the required petition fee has been paid.
