Total artificial spino-laminar prosthetic replacement

A total artificial spinous process (spino)-laminar prosthesis (TASP-LP) including a body having a portion forming a spinous process extending away from the body, a first lamina portion extending from a first side of the body, and a second lamina portion extending from a second side of the body, wherein the first lamina portion and the second lamina portion are disposed on opposite sides of the spinous process.

FIELD OF THE INVENTION

The present invention is directed to a unique total artificial spinous process (spino)-laminar prosthesis (hereinafter “TASP-LP”), and a method of implanting a TASP-LP, and more particularly, to customized patient specific TASP-LP devices including single modular replacement TASP-LP devices of varying lengths and widths, and double and triple modular replacement TASP-LP devices, along with methods of performing single-level surgical laminectomy and multilevel laminectomies using such devices.

BACKGROUND OF THE INVENTION

Posterior spinal laminectomies are performed to decompress the spinal cord and/or nerve roots contained within the spinal canal. Decompressive laminectomies are performed to relieve degenerative stenosis, herniated/bulging discs, and traumatic stenosis. In addition, they are performed in order to access the spinal canal to enable the removal and/or treatment of benign or malignant tumors, vascular lesions, abscesses, other masses, syrinxes, and a host of other conditions.

Posterior laminectomies can be performed on every spinal element throughout the entire spine including cervical, thoracic and lumbar. Laminectomies leave the posterior neural elements exposed without their native protection provided by dorsal protective lamina/spinous processes, and can lead to short and/or long term deformity and/or kyphosis. Delayed kyphosis, particularly in the cervical spine is typically remedied with the performance of posterior instrumented fusions which have an increased risk of neuro-vascular complications.

Kyphotic deformities secondary to laminectomies are more prevalent in the cervical spine. As a result of this multiple versions of a technique called laminoplasty have been developed for the cervical spine. This technique entails, opening up the lamina on one side, and using a variety of plates and screws to reattach the opened lamina to the remaining native lamina. These techniques can be cumbersome, time consuming, and also may have increased likelihood of dural tears, and nerve root injuries compared to the performance of straight forward laminectomies. However, laminoplasties as a result of protecting the cervical dura may have a less likely chance of leading to delayed kyphotic deformities.

Currently there is limited attention/technology developed for laminoplasty techniques related to thoracic/or lumbar spines. There are no other known devices that provide total artificial spinous process-laminar replacements (prostheses) mechanically designed for the explicit purposes of laminoplasty, i.e. to enlarge the diameter of the spinal canal and reconstruct the natural spinolaminar anatomy to protect exposed neural elements.

U.S. Application to Vittur et. al (Spinous process implants and methods; U.S. Pub No: US 2008/0281360 A1) describes embodiments of a replacement spinous process with a flat or concave single piece laminar portion extending anteriorly and inferiorly, and not laterally. It's lack of concavity when applied to the spine does not allow for the expansion of the dural spinal space, which is mandatory for a stenotic thecal sac decompression, and hence is not suitable for the purposes of a decompressive laminoplasty/laminectomy. Its primary purpose is to replace injured spinous processes, in order to “provide and maintain separation between spinous processes”. The device is predominantly contoured to fit an inter-spinous spacer (specifically the DIAM spinal stabilization system of Medtronic), to distract spinous processes. It is not attached directly to the lamina. It is somewhat cumbersome with laterally protruding separate or built-in connecting elements which in turn are attached to anchors which in turn are secured to pedicle screws. No embodiment is capable of replacing more than one spinal element.

Other device embodiments presented by Vittur et. al. (Posterior stabilization and spinous process systems and methods; U.S. Pub. No. US 2008/0281361 A1, Pub date Nov. 13, 2008) include multiple embodiments of spinous process replacements which do not in any way geometrically reproduce the spinous process anatomy, and are essentially devices designed to crosslink two elongated parallel bars, which in turn are attached to pedicle screws. This device “is integrated with posterior stabilization instrumentation so that interspinous stabilization procedures can be completed even if the spinous process of the patient is removed . . . ” This device is not designed, or considered, to be, a total spinolaminar replacement, nor is it suitable for a laminectomy/laminoplasty. It does not attach directly to the spine, rather it is attached to parallel bars, which in turn are secured by pedicle screws which are attached to the spine.

U.S. Applications and Patent to Bruneau et. al (Artificial Spinous Process for the Sacrum and Methods of its use; U.S. 2007/0191834 A1—Pub Aug. 16, 2007), U.S. Pat. No. 7,837,711 B2; patented Nov. 23, 2010, and U.S. 2010/0268277 A1; Pub Oct. 21, 2010) describe a device that attaches to the sacrum and provides a support for positioning an implant to dampen the relative movements during flexion and extension exclusively between the sacrum and the fifth lumbar vertebrae. The purpose of this implant is to fortify, not replace, the S1 (first sacral) vertebrae, which may not be well defined and therefore inadequate to support an implant. Specifically, the device is not a spinolaminar replacement or a spinous process replacement. It is positioned along the lateral sides of the S1 process, and its lateral extensions are uniquely designed only for the sacral anatomy. Another embodiment described by Bruneau et. al has extensions which then connect to anchors which are screwed into the sacrum. This device is not adaptable for any position of the spine other than L5-S1. Furthermore, is it not directly attached to the lamina, but rather has lateral protruding elements which in turn are attached to lateral extensions which in turn are attached to sacral screws. This device replaces neither lamina nor spinous processes.

U.S. Patent to Gielen et al. (Lamina Prosthesis for delivery of medical treatment; U.S. Pat. No. 6,481,440 B2; Nov. 19, 2002) disclose a unilateral laminar prosthetic which only replaces a portion of a lamina unilaterally and is configured with means for delivering a variety of medical treatments, such as electrodes, fluid channels, catheters and drugs. It is not secured to remaining lamina; rather it is secured to vertebral bodies with conventional bonding glue or similar technology. This device substitutes a portion of a hemi-lamina for the explicit purposes of delivering ancillary treatment. It is not considered a total spinolaminar replacement, nor does its design reflect such a purpose.

U.S. Application to Williams (Bone anchored surgical mesh; Pub. No. US 2006/0264948 A1; Published Nov. 23, 2006) describes a bone anchored surgical mesh to cover the spinal cord after a laminectomy. This perforated mesh offers an inadequate protective cover of posterior spinal elements, and lacks the strength of a total spinolaminar replacement which recreates the solid anatomy of the spinal posterior elements which is necessary to protect and strengthen the post-laminectomy spine.

U.S. Application to Mir (Spinous Process cross-link; US 2010/0249842 A1; Pub: Sep. 30, 2010) presents a prosthetic spinous process crosslink similar to Vittur et al. which attaches to the spine by gripping feet extensions which grip rods which are secured to pedicle screws, or directly grip pedicle screws.

SUMMARY OF THE INVENTION

These problems and others are addressed by the present invention, an exemplary embodiment of which includes a total artificial spinous process (spino)-laminar prosthesis (TASP-LP) which is specifically designed as a laminoplasty alternative, i.e. to expand the spinal canal by the performance of a laminectomy and to replace one or multiple total spinolaminar units in order to reconstitute the strength and structural integrity of the natural pre-laminectomy spinolaminar anatomy, as well as to protect the underlying posterior spinal neural elements.

Hence, the present invention provides an exemplary single unit TASP embodiment that reproduces the natural concavity of the lamina, extends laterally (right and left), and not anteriorly/posteriorly, in order to specifically accommodate and allow the expansion of the decompressed stenotic spine. Furthermore, these lamina fan out with lateral extensions that are parallel to the remaining lamina (outside the laminectomy field), with perforations for translaminar or facet screws which allows for the simple direct attachment of the prosthesis to the spine. The present invention provides important advantages in that there is no need for an additional set of cumbersome connecting elements which connect to separate anchors, parallel bars, rods, and/or pedicle screws, all of which add complexity, time, and morbidity to the surgical procedure. Furthermore, the exemplary single unit embodiments can replace one, two or three spinolaminar units at a time, unlike any of the conventional devices mentioned above. In addition, the exemplary embodiments can include either laminar hinged extensions or artificial spinous process hinges to actively widen the TASP to account for intra and inter-patient spinal canal width variability, and to accommodate for inter and inter-patient laminar topography variability. These exemplary embodiments allow custom fitting of the device for all different inter and intra-patient anatomies. Furthermore, exemplary cervical and thoracic/lumbar TASPs are designed completely differently from each other in order to account for differences between cervical and thoracic/lumbar anatomies, e.g. the spinous process of an exemplary cervical TASP is bifid replicating the natural cervical anatomy, among other significant differences detailed below.

For example, the above-identified problems and others are addressed by the present invention, an exemplary embodiment of which includes a total artificial spinous process (spino)-laminar prosthesis (TASP-LP) comprising a body having a portion forming a spinous process extending away from the body; a first lamina portion extending from a first side of the body; and a second lamina portion extending from a second side of the body, wherein the first lamina portion and the second lamina portion are disposed on opposite sides of the spinous process.

The spinous process can include an opening for muscle or fascia suture attachment, or a plurality of openings for muscle or fascia suture attachment. The spinous process can include, for example, two lobes mimicking a natural anatomy of a spinal element, or a single lobe mimicking a natural anatomy of a spinal element. Each of the two lobes can include an opening for muscle or fascia suture attachment.

In another embodiment, each of the first lamina portion and the second lamina portion can include an opening for receiving an attachment device for securing the first lamina portion and the second lamina portion to natural lamina of a spinal element.

The TASP-LP can include an attachment device engaging the opening. The attachment device can include, but is not limited to, for example, a translaminar screw, a flathead screw, a self-tapping screw, etc. Other suitable attachment devices are contemplated by the invention. For example, the attachment device can include a pin, such as a flat pin, a round pin, a pin having hooks, and a pin having ridges, or another attachment device, such as a staple. The staple can include a flat portion, a round portion, a portion having hooks, or a portion having ridges.

A surface of each of the first lamina portion and the second lamina portion can include a recess surrounding the opening for receiving a head of the attachment device such that the head of the attachment device is countersunk into or flush with the surface. A surface of each of the first lamina portion and the second lamina portion can engage the attachment device to lock the attachment device with the surface. In other embodiments, each of the first lamina portion and the second lamina portion can include a plurality of openings for receiving attachment devices. In another embodiment, the TASP-LP can include a plurality of attachment devices respectively engaging the plurality of openings.

In another exemplary embodiment, each of the first lamina portion and the second lamina portion can include an underside facing away from the body and having a contoured portion. A contour of the contoured portion of the underside of the first lamina portion can be different than a contour of the contoured portion of the underside of the second lamina portion.

In another exemplary embodiment, each of the first lamina portion and the second lamina portion can includes a relief opening or groove that permits each of the first lamina portion and the second lamina portion to flex. In other embodiments, each of the first lamina portion and the second lamina portion can includes a pair of openings for receiving attachment devices, and each of the first lamina portion and the second lamina portion can include a relief opening or groove between the pair of openings that permits each of the first lamina portion and the second lamina portion to flex along an area adjacent to each of the pair of openings.

In another exemplary embodiment, each of the first lamina portion and the second lamina portion can includes a thinned portion having a thickness that is less than a thickness of an adjacent portion, thereby permitting each of the first lamina portion and the second lamina portion to flex at the thinned portion.

In another exemplary embodiment, the TASP-LP can include a first hinged extension that is movable with respect to the first lamina portion and a second hinged extension that is movable with respect to the second lamina portion. The TASP-LP can include a first hinge pin rotatably coupling the first hinged extension to the first lamina portion; and a second hinge pin rotatably coupling the second hinged extension to the second lamina portion, wherein each of the first hinged extension and the second hinged extension is pivotable with respect to the first lamina portion and the second lamina portion, respectively, for allowing individualized alignment of the first hinged extension and the second hinged extension with natural laminar having differing inclines. Each of the first hinged extension and the second hinged extension can be pivotable between a neutral position that is parallel to a plane of the first lamina portion and the second lamina portion, respectively, an elevated position that is at a positive angle with respect to the plane, and a depressed position that is at a negative angle with respect to the plane.

In another exemplary embodiment, the spinous process can include a first spinous process portion and a second spinous process portion, wherein the first spinous process portion and the second spinous process portion are pivotable with respect to each other to change a distance between the first lamina portion and the second lamina portion, thereby allowing for accommodating for different laminectomy widths. The TASP-LP can include a spinous process hinge rotatably coupling the first spinous process portion and the second spinous process portion. The TASP-LP can include a first hinged extension that is movable with respect to the first lamina portion and a second hinged extension that is movable with respect to the second lamina portion, wherein the spinous process comprises a first spinous process portion and a second spinous process portion, and wherein the first spinous process portion and the second spinous process portion are pivotable with respect to each other to change a distance between the first lamina portion and the second lamina portion.

In another exemplary embodiment, the TASP-LP can include a first hinged extension that is movable with respect to the first lamina portion; a first hinge pin rotatably coupling the first hinged extension to the first lamina portion; a second hinged extension that is movable with respect to the second lamina portion; a second hinge pin rotatably coupling the second hinged extension to the second lamina portion, wherein each of the first hinged extension and the second hinged extension is pivotable with respect to the first lamina portion and the second lamina portion, respectively, for allowing individualized alignment of the first hinged extension and the second hinged extension with natural laminar having differing inclines, and wherein the spinous process comprises a first spinous process portion; a second spinous process portion, and a spinous process hinge rotatably coupling the first spinous process portion and the second spinous process portion, wherein the first spinous process portion and the second spinous process portion are pivotable about the spinous process hinge to change a distance between the first lamina portion and the second lamina portion for allowing for accommodating of different laminectomy widths.

In another exemplary embodiment, one of the body, the spinous process, the first lamina portion, and the second lamina portion comprises titanium. In yet another exemplary embodiment, one of the body, the spinous process, the first lamina portion, and the second lamina portion comprises a bio-compatible material

In another exemplary embodiment, the TASP-LP can include a second body having a second portion forming a second spinous process extending away from the second body; a third lamina portion extending from a first side of the second body; a fourth lamina portion extending from a second side of the second body, wherein the third lamina portion and the fourth lamina portion are disposed on opposite sides of the second spinous process; a first bridge coupling the first lamina portion of the body to the third lamina portion of the second body; and a second bridge coupling the second lamina portion of the body to the fourth lamina portion of the second body. In an exemplary embodiment, the first lamina portion of the body can be integrally formed with the third lamina portion of the second body; and the second lamina portion of the body can be integrally formed with the fourth lamina portion of the second body.

In another exemplary embodiment, the TASP-LP can include a third body having a third portion forming a third spinous process extending away from the third body; a fifth lamina portion extending from a first side of the third body; a sixth lamina portion extending from a second side of the third body, wherein the fifth lamina portion and the sixth lamina portion are disposed on opposite sides of the third spinous process; a third bridge coupling the third lamina portion of the second body to the fifth lamina portion of the third body; and a fourth bridge coupling the fourth lamina portion of the second body to the sixth lamina portion of the third body.

In another exemplary embodiment, the TASP-LP can include a second body having a second portion forming a second spinous process extending away from the second body; a third lamina portion extending from a first side of the second body; a fourth lamina portion extending from a second side of the second body, wherein the third lamina portion and the fourth lamina portion are disposed on opposite sides of the second spinous process; and a connecting bridge coupling the spinous process of the body to the second spinous process of the second body.

In another exemplary embodiment, the TASP-LP can include a second body having a second portion forming a second spinous process extending away from the second body; a third lamina portion extending from a first side of the second body; a fourth lamina portion extending from a second side of the second body, wherein the third lamina portion and the fourth lamina portion are disposed on opposite sides of the second spinous process; and a connecting bridge coupling the spinous process of the body to the second spinous process of the second body. The spinous process of the body can be integrally formed with the second spinous process of the second body.

In another exemplary embodiment, one of the body, the spinous process, the first lamina portion, and the second lamina portion can include a cavity or area for receiving bone material. Also, one of the body, the spinous process, the first lamina portion, and the second lamina portion can include an opening for muscle or fascia suture attachment.

In another exemplary embodiment of the invention, a total artificial spinous process (spino)-laminar prosthesis (TASP-LP) can include at least two of a first module, a second module, and a third module, wherein each of the first module, the second module, and the third module can comprise a body having a portion forming a spinous process extending away from the body; a first lamina portion extending from a first side of the body; and a second lamina portion extending from a second side of the body, wherein the first lamina portion and the second lamina portion are disposed on opposite sides of the spinous process. The first module can be integrally formed with the second module.

In another exemplary embodiment, the TASP-LP can include the first module, the second module, and the third module, wherein the first module, the second module, and the third module are integrally formed with each other.

In other embodiments, an overall shape, a height, a width, an orientation, and an angulation of the body, the spinous process, the first lamina portion, and the second lamina portion mimics an overall shape, a height, a width, an orientation, and an angulation of a natural spine portion based on a 3-dimensional computer rendition of the natural spine portion.

Another exemplary embodiment of the invention includes a method of implanting the exemplary embodiments of the total artificial spinous process (spino)-laminar prosthesis (TASP-LP) in which the method includes measuring dimensions and geometry of a natural spine portion of a patient; generating a 3-dimensional computer rendition of the natural spine portion; forming the body, the spinous process, the first lamina portion, and the second lamina portion to mimic the natural spine portion based on the 3-dimensional computer rendition of the natural spine portion. In an embodiment of the method, the dimensions and the geometry of the natural spine portion can be generated using MRI-CT imaging techniques. An overall shape, a height, a width, an orientation, and an angulation of the body, the spinous process, the first lamina portion, and the second lamina portion can be measured. An overall shape, a height, a width, an orientation, and an angulation of the body, the spinous process, the first lamina portion, and the second lamina portion of the total artificial spinous process (spino)-laminar prosthesis (TASP-LP) are formed to mimic the overall shape, the height, the width, the orientation, and the angulation of the natural spine portion based on the 3-dimensional computer rendition of the natural spine portion.

In another exemplary embodiment, the method can include coupling the total artificial spinous process (spino)-laminar prosthesis (TASP-LP) to a natural spine in place of the natural spine portion.

In another exemplary embodiment, the TASP-LP can include a first hinged extension that is movable with respect to the first lamina portion and a second hinged extension that is movable with respect to the second lamina portion, and the method can include pivoting each of the first hinged extension and the second hinged extension with respect to the first lamina portion and the second lamina portion, respectively, to individually align the first hinged extension and the second hinged extension with individual inclines of the natural spine.

In another embodiment, the spinous process can include a first spinous process portion and a second spinous process portion, wherein the first spinous process portion and the second spinous process portion are pivotable with respect to each other to change a distance between the first lamina portion and the second lamina portion, wherein the method can includes pivoting the first spinous process portion and the second spinous process portion with respect to each other to change the distance between the first lamina portion and the second lamina portion. The TASP-LP can include a first hinged extension that is movable with respect to the first lamina portion and a second hinged extension that is movable with respect to the second lamina portion, wherein the spinous process comprises a first spinous process portion and a second spinous process portion, wherein the first spinous process portion and the second spinous process portion are pivotable with respect to each other to change a distance between the first lamina portion and the second lamina portion, and wherein the method can includes pivoting the first spinous process portion and the second spinous process portion with respect to each other to change the distance between the first lamina portion and the second lamina portion; and pivoting each of the first hinged extension and the second hinged extension with respect to the first lamina portion and the second lamina portion, respectively, to individually align the first hinged extension and the second hinged extension with individual inclines of the natural spine.

Another embodiment is directed to a method of implanting a total artificial spinous process (spino)-laminar prosthesis (TASP-LP), the method comprising measuring dimensions and geometry of a natural spine portion of a patient; generating a 3-dimensional computer rendition of the natural spine portion; forming the at least two of the first module, the second module, and the third module to mimic the natural spine portion based on the 3-dimensional computer rendition of the natural spine portion. The method can include coupling the at least two of the first module, the second module, and the third module to a natural spine in place of the natural spine portion. In the exemplary method, the first module can be integrally formed with the second module. The total artificial spinous process (spino)-laminar prosthesis (TASP-LP) can include the first module, the second module, and the third module, wherein the first module is integrally formed with the second module, and wherein the third module is separate from the first module and the second module. The first module can be integrally formed with the second module and the third module.

An exemplary embodiment of the method can include selecting a combination and arrangement of the first module, the second module, and the third module based on a width and a length of the natural spine portion; and coupling the selected combination and arrangement of the first module, the second module, and the third module to a natural spine in place of the natural spine portion.

An embodiment of the present invention is directed to a unique total artificial spinous process (spino)-laminar prosthesis (hereinafter “TASP-LP”) that is implanted dorsally onto the spine after the performance of a spinal laminectomy. A single-level surgical laminectomy entails the removal of a single unit comprising two lamina, right and left, and a single mid-line spinous process. Multilevel laminectomies entail the removal of two or more of these units. The exemplary embodiments of a total artificial spinous process-laminar replacement can be tailor-made to address the multiplicity of laminar-spinous process units removed as a result of a laminectomy in need of artificial replacement/reconstruction. The TASP-LP therefore can include, for example, single modular replacement embodiments of varying lengths and widths addressing single and multiple spino-laminar (SL) unit replacements. In addition, other exemplary embodiments can include double and triple modular embodiments which along with single modules can create hybrid prosthetics for multi-level SL unit replacements.

Other exemplary TASP-LP embodiments can include, for example: a) a device with expandable hinged spinolaminar wings that can accommodate different laminectomy widths, b) a device with hinged laminar extensions which can accommodate individualized laminar inclines, and c) a device with both hinged expandable spinous process-laminar wings and hinged laminar extensions.

An exemplary embodiment of the invention can further individualize the device by using MRI-CT imaging techniques to accurately measure precise spinous process-laminar dimensions and geometry of a particular patient in order to enable highly accurate tailor-made manufactured computerized modular reconstructions for different individuals.

The exemplary embodiments of the invention can obviate the need for cumbersome and complicated laminoplasties, and also serve to recreate normal spinal anatomy after the performance of deforming and potentially destabilizing laminectomies.

The exemplary embodiments of the present invention address the anatomical deficiencies created by the performance of a spinal laminectomy, and seek to artificially recreate the normal spino-laminar anatomy after a laminectomy.

The exemplary embodiments of the invention can provide important advantages, for example, including:

1) protecting the dura of spinal cord and/or nerve roots from traumatic exposure;

2) providing an artificial muscle/facial point of attachment, therefore replicating the normal function of the spinous processes; and/or

3) preventing kyphotic deformity and instability of the spine thereby obviating the need for simultaneous or delayed posterior fusions which increase the risk of nerve root, spinal cord or vascular injuries.

Furthermore, the exemplary embodiments of the invention may provide important advantages over conventional devices and methods associated with laminoplasties in the cervical spine in that the exemplary embodiments may be less cumbersome, takes less time to install, and have lower risk of cord, nerve root injury or dural tear/spinal fluid leak. Moreover, the application of the exemplary embodiments of the invention to post thoracic and lumbar spinal laminectomies, may decrease the risk of spinal deformity, increase protection of spinal elements, decrease the need for fusions, and hence decrease the overall risk of spinal laminectomies, thereby improving overall quality of life for the recipient of the TASP-LP.

In another embodiment, a set or kit of a plurality of prostheses can be provided, each having different standard sizes, such that a surgeon easily can select one or more appropriately sized prostheses. The selected prosthesis each can have the same size or different sizes depending on the dimensions of the natural spinal portions of a given recipient.

Other features and advantages of the present invention will become apparent to those skilled in the art upon review of the following detailed description and drawings.

Referring now to the drawings,FIGS. 1-12Billustrate exemplary embodiments of a TASP-LP that can solve the aforementioned problems in the cervical, thoracic and lumbar spine by implantation of a TASP-LP into the post-laminectomy spine.

FIGS. 1A-Dillustrate a plurality of different views of an exemplary embodiment of a cervical TASP-LP (Embodiment IA) including a single one piece total prosthetic module10that can replace a single natural cervical spinous process laminar (left and right) unit.

The total prosthetic module10can include, for example, a prosthetic spinous process12and left prosthetic lamina14and right prosthetic lamina16. The prosthetic spinous process12can include perforations20for muscle suture attachment. The left prosthetic lamina14and right prosthetic lamina16can include screw attachments18for receiving translaminar screws22.

An exemplary embodiment of a cervical TASP-LP construction can be based on a 3-D CT computer rendition which very closely recreates the natural geometric anatomy of the healthy human cervical spine. Hence, an exemplary embodiment of a cervical prosthetic spinous process12of the TASP-LP10can be bifid (i.e., divided into two lobes), just like the predominant bifid spinous process anatomy of the natural cervical spine30.

Likewise, using 3-D computer modeling software, in an exemplary embodiment, the slope and angulations of the prosthetic spinous process12, and of left and right prosthetic lamina14,16, can be rendered in accord with the natural spinous process34and of left and right natural lamina30,32of the healthy natural cervical spine30. Hence, as illustrated in the exemplary embodiment ofFIG. 1E, when a cervical TASP-LP single module10(Embodiment IAi) is implanted into the natural cervical spine30, the overall shape, height, and spinous process and laminar orientations and angulations of the cervical TASP-LP can mimic the surrounding natural cervical spinous processes34and lamina30,32to render the prosthesis almost indistinguishable from the natural cervical spine30in which it is embedded.

With reference toFIG. 1F, an exemplary embodiment of a slightly different singular module10a(Embodiment IAii) will now be described in which the undersurfaces of the laminar mounting surfaces40can be contoured to approximate the shape of the underlying cervical lamina (e.g.,30,32) to which the prosthesis10ais mounted.

FIGS. 1G-Hillustrate yet another exemplary embodiment of the single module10b(Embodiment IAiii) including a relief (e.g., laminar mounting relief44) added on each side that enables slight flexing for mounting. In addition, the prosthetic lamina14,16can be thinned (e.g., thinned laminar section42) to thereby also allow slightly more flexibility. The features of the exemplary embodiment can be facilitated by producing the exemplary prosthesis10busing titanium or similar bio-compatible materials.

FIG. 1Hillustrates a cross-sectional view of an exemplary embodiment that demonstrates that flat screw heads (e.g., flat head mounting trans-laminar screws22a) can be countersunk into the surface, whereby the screws22aare, for example, locked into position.

The exemplary embodiments of the prosthetic spinous process12can include perforations20on either side of the bifid process12to enable suturing of cervical muscles and fascia to the prosthetic spinous process12, to reconstruct the normal cervical muscular architecture. The left and right prosthetic lamina14,16can include, for example, two perforations18on its extensions, thereby enabling the fixation of the TASP-LP to the natural lamina (FIG. 1E) by translaminar screws22a.

FIGS. 2A and 2Billustrate an exemplary embodiment of a cervical TASP-LP100(embodiment IA) that can be modularly applied to two and three level multi-level laminectomies. Other exemplary embodiments can likewise be applied to four, five, etc. multi-level laminectomies in a modular manner.

FIG. 2Aillustrates an exemplary embodiment in which a TASP-LP module100a(module #1), and module100b(module #2) are inserted into a 2 level post-laminectomy natural cervical spine30.FIG. 2Billustrates an exemplary embodiment in which TASP-LP modules100a,100b,100c(modules #1, #2, and #3) are inserted into a 3-level post-laminectomy natural cervical spine30. In bothFIGS. 2A and 2B, the prosthetic modules100a,100b,100ccan reproduce and artificially reconstruct the natural geometry of the healthy human spine30.

In other exemplary embodiments, the different modules can be manufactured in different heights, lengths, and widths so that the surgeon can select from the properly sized one to integrate with the selective anatomy of different patients.

FIG. 3Aillustrates an exemplary embodiment (Embodiment IB) including a double spinous process-laminar prosthetic unit200. The prosthetic unit200can be a single piece and can be similar to the single module TASP-LP (Embodiment IA, e.g.,10,10a,100a,100b,100c). However, in the illustrated embodiment, the prosthetic unit200can include two modules unified (e.g., integrally formed) into one piece with modular laminar connecting bridges202on the left and right sides of the prosthesis200. Thus,FIG. 3Ashows the implantation of a double spinous process-laminar prosthetic module200(Embodiment IB) and a single spinous-laminar prosthetic module (embodiment IA, e.g.,10) into a 3-level post-laminectomy cervical spine30. This is essentially a hybrid reconstruction. The surgeon can choose to replace three natural units with either 3 single TASP-LP modules (Embodiment IA, e.g.,10), or with a combination of a double TASP-LP module200(Embodiment IB) and a single TASP-LP module (Embodiment IA, e.g.,10), or with a single Triple TASP-LP module (embodiment IC, e.g.,100a,100b,100c) as illustrated, for example, inFIG. 3B. This triple embodiment300(FIG. 3B) can include three modules fused, or integrally formed, into one using two modular connecting bridges302on the right and left sides of the module300.

FIGS. 4A-Dillustrate a plurality of different views of an exemplary embodiment of a Thoracic/Lumbar TASP-LP10(Embodiment IAi). The Thoracic/Lumbar TASP-LP can be a single one piece total prosthetic module10which replaces a single natural Thoracic/Lumbar spinous process-laminar (left and right) unit based on, for example, 3-D CT computer modeling, and can very closely reproduce the normal anatomy of the Thoracic/Lumbar spine. Hence, the exemplary prosthetic spinous process12can be monofid, just like the natural anatomy for the majority of the Thoracic and Lumbar spinal elements. The slope and angulations of the exemplary prosthetic spinous process12, and of the left and right prosthetic lamina14,16can be rendered in accord with the normal Thoracic/Lumbar anatomy using 3-D computer modeling technology. Hence, as illustrated inFIG. 1E, when the Thoracic/Lumbar TASP-LP single module (Embodiment IAi) is implanted into the natural Lumbar spine, the overall shape, height, and the spinous process12and laminar orientations and angulations of the prosthesis can mimic the surrounding natural Lumbar spinous processes and lamina, rendering the prosthesis10almost indistinguishable from the natural Lumbar spine in which it is embedded.

An exemplary prosthetic spinous process12can include perforations to enable suturing of Thoracic/Lumbar muscles and fascia to the prosthesis, to reconstruct the normal muscle orientation and architecture. The left and right prosthetic lamina can include, for example, three perforations on its extensions, which can enable the fixation of the TASP-LP to the natural lamina by trans-laminar screws as exemplarily illustrated inFIG. 4E.

FIG. 4Fillustrates another exemplary embodiment of a single modular Lumbar-Thoracic TASP-LP10a(Embodiment IAii) wherein the prosthesis10acan include a different contour and two perforations18(instead of three perforations) on either side for trans-laminar screw mounting.

FIG. 4Gillustrates yet another exemplary embodiment of a single modular Lumbar/Thoracic TASP-LP10a(Embodiment IAiii) wherein a relief44can be added on each side to make the prosthesis somewhat more malleable and flexible. Similarly, the prosthetic laminar edges can be somewhat more thinned out for the sake of increased malleability. These features may be more amenable to production of the prosthesis in titanium or any biocompatible material with similar properties.

FIGS. 5A and 5Billustrate an exemplary embodiment of a Thoracic/Lumbar TASP-LP10(Embodiment IA) that can be modularly applied to two and three level multi-level laminectomies. This embodiment likewise can be applied to four, five, etc. multi-level laminectomies in a modular manner.FIG. 5Aillustrates an exemplary embodiment of a Thoracic/Lumbar TASP-LP module100a,100b(module #1and module #2) inserted into a 2 level postlaminectomy natural Lumbar spine30.FIG. 5Billustrates an exemplary embodiment of TASP-LP modules100a,100b,100c(modules #1, #2, and #3) inserted into the 3-level post-laminectomy natural Lumbar spine30. In bothFIGS. 5A and 5B, the prosthetic modules can reproduce and artificially reconstruct the natural geometry of the spine.

The different modules100a,100b,100ccan be manufactured in different heights, lengths, and widths so that the surgeon can select from different sizes to accommodate for differences in patient anatomy.

FIGS. 6A and 6Billustrate other exemplary embodiments of a Thoracic/Lumbar TASP-LP (Embodiments IB and IC, respectively).FIG. 6Aillustrates an exemplary embodiment (Embodiment IB) including a double spinous process-laminar prosthetic unit200a. The prosthetic unit200acan be, for example, a single piece and can be technically similar to the single module TASP-LP10(Embodiment IA) described herein. However, in this embodiment, two modules can be unified into one piece (e.g., integrally formed) with a modular connecting bridge204joining the adjacent prosthetic spinous processes12. Thus,FIG. 6Aillustrates the implantation of an exemplary double Thoracic/Lumbar spino-laminar prosthetic module200a(Embodiment IB) and an exemplary single Thoracic/Lumbar spino-laminar prosthetic module10(Embodiment IA) into a 3-level post-laminectomy cervical spine30. This embodiment can be essentially a hybrid reconstruction. In this manner, the surgeon can choose to replace three natural units with either three (3) single TASP-LP modules (10,10a, etc.) (Embodiment IA) or with a double TASP-LP module (200,200a) (Embodiment IB) and a single TASP-LP unit (10,10a, etc.) (Embodiment IA), or with a single triple TASP-LP module300(Embodiment IC) as exemplarily illustrated inFIG. 3B, or with a single triple TASP-LP module300aas exemplarily illustrated inFIG. 6B. The triple embodiment300(FIG. 3B) can include three modules fused, or integrally formed, into one using two modular connecting bridges302on the right and left sides of the module300. The triple embodiment300a(e.g., as illustrated in FIG.6A) can include three modules fused into one (e.g., integrally formed), for example, using two modular connecting bridges304connecting three modular prosthetic spinous processes12.

FIGS. 7A-Dillustrate an exemplary embodiment of another cervical TASP-LP400(Embodiment II). This embodiment differs from Embodiment I in that the prosthesis400can include left and right prosthetic laminar hinged extensions402,404. These hinged extensions can be attached to the prosthetic lamina14,16with hinge pins406,408, for example, as illustrated inFIG. 7D. Thus, the exemplary hinges406,408can be moved up and down like doors allowing individualized accommodating alignment of the TASP-LP400with differing natural laminar inclines.FIG. 7Aillustrates the laminar hinged extensions402,404in neutral position.FIG. 7Billustrates the laminar hinged extensions402,404in elevated positions.FIG. 7Cillustrates the laminar hinged extensions402,404in depressed positions.FIG. 7Dillustrates an exploded view of the exemplary embodiment ofFIGS. 7A-7C(Embodiment II). The left and right prosthetic laminar hinges406,408can be attached to the hinged TASP-LP prosthesis with pins410,412or other suitable connecting devices. The hinged extensions402,404can rotate about the pin410,412allowing significant up and down movement for allowing placement on varying natural laminar inclines, thereby accounting for patient variability.

FIGS. 8A-Dillustrate an exemplary embodiment of a Cervical TASP-LP500(Embodiment III). This embodiment differs from the embodiment ofFIGS. 7A-7C(e.g., Embodiments I and II), in that the prosthetic spinous process12can comprise left and right winged spinous process-laminar hinges502,504which allow elevation or depression of the two hemi-segments of the prosthesis, thus enabling a varying degree of widening of the prosthesis. This embodiment can allow prosthetic accommodation for different laminectomy widths, thereby taking into account differences in inter-patient anatomy, and surgically created laminectomy widths. These two hinged winged hemi-segments502,504can rotate, for example, about a spinous process laminar hinge pin506, or other suitable part, which provides it with the capacity to accommodate for smaller or larger laminectomy widths.FIGS. 8A, 8B, and 8Cillustrate the exemplary embodiment in neutral, elevated and depressed positions, respectively.FIG. 8Dillustrates an exploded view of the exemplary embodiment ofFIGS. 8A-8C, including the left prosthetic spinous process-laminar hinge502, the right prosthetic spinous process laminar hinge504, and the hinge pin506.

FIGS. 9A and 9Billustrate an exemplary embodiment of a cervical TASP-LP600(Embodiment IV). This exemplary embodiment can combine, for example, all the features in Embodiments I, II, and III. For example, the illustrated embodiment includes both left and right prosthetic winged spinous process-laminar hinges602,604which allow movement around a spinous process laminar hinge pin606, and left and right laminar hinged extensions608,610which allow elevation or depression of these hinges via their rotation around the laminar extension hinge pins612,614. Thus, this embodiment can enable accommodation both for differences in varying laminar inclines, by altering the position of its laminar hinge extensions, and for differences in laminectomy widths by widening the device by repositioning the left and right prosthetic spinous-process-laminar hinges602,604.

FIGS. 10A-Dillustrate an exemplary embodiment of a Thoracic/Lumbar TASP-LP700(Embodiment II). This embodiment differs from Embodiment I, in that the embodiment includes left and right prosthetic laminar hinged extensions702,704. These hinged extensions702,704can be attached to the prosthetic lamina, for example, with hinge pins706,708as illustrated inFIG. 10Dor other suitable devices. Thus, the hinged extensions702,704can be moved up and down like doors allowing individualized alignment of the TASP-LP700with the natural incline of different patients' spinal laminar anatomy.

For example,FIG. 10Aillustrates the prosthetic laminar hinged extensions702,704in neutral position.FIG. 10Billustrates the prosthetic laminar hinged extensions702,704in elevated positions.FIG. 10Cillustrates the prosthetic laminar hinged extensions702,704in depressed position.FIG. 10Dillustrates the exploded view of embodiment II. The left and right prosthetic laminar hinged extensions702,704can be attached to the hinged TASP-LP prosthesis, for example, with pins706,708or similar devices. The hinged extensions702,704can rotate about the pin706,708allowing significant up and down movement allowing placement on varying natural inclines accounting for patient anatomical variation.

FIGS. 11A-Dillustrate an exemplary embodiment of a Thoracic/Lumbar TASP-LP800(Embodiment III). This embodiment differs from Embodiments I and II, in that the prosthetic spinous process12can comprise left and right winged prosthetic spinous process-laminar hinges802,804which allow elevation or depression of the two hemi-segments of the prosthesis enabling a varying degree of widening of the prosthesis. This embodiment can allow prosthetic accommodation for different laminectomy widths, thus accounting for differences in inter-patient anatomy, and surgically created laminectomy widths. These exemplary two winged hinged hemi-segments802,804can rotate, for example, about a spinous process laminar hinge pin806or other suitable device which provides it with the capacity to accommodate for smaller or larger laminectomy widths.FIGS. 11A, 11B, and 11Cillustrate this exemplary embodiment in neutral, elevated and depressed positions, respectively.

FIG. 11Dillustrates an exploded view ofFIGS. 11A-11Cincluding the left prosthetic winged spinous process-laminar hinge802, the right winged prosthetic spinous process laminar hinge804, and the spinous process-laminar hinge pin806.

FIGS. 12A and 12Billustrate an exemplary embodiment of a Thoracic/Lumbar TASP-LP900(Embodiment IV). This embodiment combines all the features in Embodiments I, II, and III and can include, for example, both left and right winged prosthetic spinous process-laminar hinges902,904which allow movement around a spinous process-laminar hinge pin906or the like, and left and right laminar hinged extensions908,910which allow elevation or depression of these hinges via their rotation around the laminar extension hinge pins912,914. Thus, this embodiment can enable accommodation both for differences in varying laminar inclines, by altering the position of its laminar hinge extensions908,910, and for differences in laminectomy widths by widening the device by repositioning the left and right prosthetic winged spinous process-laminar hinges902,904.

The exemplary embodiments of a TASP-LP can be made of any bio-compatible material including, for example, polyether ether ketone (PEEK) (e.g., a colourless organic polymer thermoplastic), titanium steel, allograft bone, or other suitable materials, etc.

The exemplary embodiments of a TASP-LP can include pins as well as screws, or other suitable fasteners. The pins can be, for example, flat or round. The pins can include, for example, fish hooks or ridges. The pins can be part of the device or a separate attachment for slots. For example, an apparatus can be used to hold the pin in place while it is being hammered or stapled into the prosthesis.

An exemplary embodiment of the TASP-LP can look like a lamina/spinous process or occupy the space of a lamina/spinous process, or be of any variant shape. The TASP-LP can include, for example, one piece, or two or more pieces assembled together. The pieces can include curves or be straight. The device can have different shapes, such as rectangular, triangular, curved or arch shaped, including for example: triangular arch, round arch, segmental arch, rampant round arch, lancet arc, equilateral pointed arch, shouldered flat arch, cusped arch, horseshoe arch, three centered arch, jack arch, inflexed arch, ogee arch, reverse ogee arch, a parabolic arch, or similar such arcs.

Other exemplary embodiments of the prosthesis can include a joint in the center or the sides for moveability. The exemplary prosthesis can include a ball joint, screw joint, revolute joint, cylindrical joint, gliding joint, mechanical linkage joints, hinges, or any other suitable joint or feature which accomplishes the same function.

Other exemplary embodiments of the prosthesis can comprise bearings, for example, such as a ‘bushing’ for absorbing shock.

In other exemplary embodiments, the prosthesis can be movable like a clip or hinge. The exemplary prosthesis can be made of flexible material and/or can be spring like.

In another exemplary embodiment, a set or kit of a plurality of prostheses can be provided, each having different standard sizes, such that a surgeon easily can select one or more appropriately sized prostheses. The selected prosthesis each can have the same size or different sizes depending on the dimensions of the natural spinal portions of a given recipient.

The Exemplary Surgical Methods

With reference again toFIGS. 1-12B, exemplary methods including surgical steps for practicing the present invention will now be described.

In an exemplary embodiment, after performing a posterior cervical laminectomy executed by standard surgical technique, the spinous process-bilaminar unit(s) of the cervical post-laminectomy spine can be artificially replaced with a single or multiple cervical TASP-LP modules. Based on a width and length (i.e., number of levels) of the laminectomy, the surgeon selects either a single, multiple, or hybrid number of TASP-LP modules according to one or more of embodiments IA, IB, IC, II, III or IV.

The TASP-LP modules can be secured to the natural lamina on both right and left sides, for example, by screwing in trans-laminar screws through the prosthesis' laminar extension perforations and into the natural remaining lamina. This step can immobilize the construct onto the natural cervical spine. The cervical fascia and muscles then can be reattached to the prosthetic spinous process(es) by passing a suture through the spinous process perforations thereby anatomically reconnecting the muscles to the prosthetic spine thereby mimicking the natural spinal anatomy.

In an exemplary embodiment, after performing a posterior thoracic or lumbar laminectomy executed by standard surgical technique, the spinous process-bilaminar unit(s) of the Thoracic/Lumbar postlaminectomy spine can be artificially replaced with a single or multiple Thoracic/Lumbar TASPLP modules. Based on the width and length (i.e., number of levels) of the laminectomy, the surgeon can select either a single, multiple, or hybrid number of TASP-LP modules according to one or more of embodiments IA, IB, IC, II, III or IV.

The Thoracic/Lumbar TASP-LP modules can be secured to the natural lamina on both right and left sides, for example, by screwing in trans-laminar screws through the prosthesis' laminar extension perforations and into the natural remaining lamina. This can immobilize the construct onto the natural thoracic or lumbar spine. The cervical fascia and muscles can then be reattached to the prosthetic spinous process(es) by passing a suture through the spinous process perforations thereby anatomically reconnecting the muscles to the prosthetic spine thereby mimicking the natural spinal anatomy.

The present invention has been described herein in terms of several preferred embodiments. However, modifications and additions to these embodiments will become apparent to those of ordinary skill in the art upon a reading of the foregoing description.

For example, the exemplary embodiments can include a total artificial spinous process (spino)-laminar prosthesis (TASP-LP) comprising one or more of the features of the cervical and Lumbar embodiments illustrated in embodiments IA, IB, IC, II, III, and IV.

The exemplary embodiments can include a method of replacing the spinous process-bilaminar unit(s) of the cervical postlaminectomy spine with a single or multiple cervical TASP-LP modules according to one or more of embodiments IA, IB, IC, II, III, and IV.

The exemplary embodiments can include a single total artificial spinous process (spino)-laminar prosthesis (TASP-LP) having varying lengths and widths.

The exemplary embodiments can include a plurality of total artificial spinous process (spino)-laminar prosthesis (TASP-LP) having varying lengths and widths.

The exemplary embodiments can include a total artificial spinous process (spino)-laminar prosthesis (TASP-LP) comprising expandable hinged spino-laminar wings to accommodate different laminectomy widths. 6. A total artificial spinous process (spino)-laminar prosthesis (TASP-LP) comprising hinged laminar extensions which can accommodate individualized laminar inclines.

The exemplary embodiments can include a total artificial spinous process (spino)-laminar prosthesis (TASP-LP) comprising both hinged expandable spinous process-laminar wings and hinged laminar extensions.

The exemplary embodiments can include a method of replacing the spinous process-bilaminar unit(s) of the Thoracic/Lumbar post-laminectomy spine with a single or multiple Thoracic/Lumbar TASP-LP modules according to one or more of embodiments IA, IB, IC, II, III, and IV.

The exemplary embodiments can include a total artificial spinous process (spino)-laminar prosthesis (TASP-LP) comprising a biocompatible material.

The exemplary embodiments can include a method of manufacturing tailor made individualized prosthetics using 3-D computerized modeling reconstructions of patients' specific geometric anatomy measured on their CT/MRIs.

The exemplary embodiments can include a TASP-LP having two or three screws, as exemplarily illustrated, or with fewer or more screws.

The exemplary embodiments can include a mounting area that can be expanded or have its shape changed to any variety of shapes to cover different areas of the bone for attachment or fixation.

The exemplary embodiments can include a prosthesis having areas for addition or incorporation of bone if a surgeon wishes to include a fusion.

The exemplary embodiments can include screws that are countersunk into the prosthetic surface for fixed locking Variations of locking mechanisms for fixed or variable angled screws can be applied. Either external or internal locking mechanisms can be employed.

The exemplary embodiments can include a prosthesis that is flexible or expandable in any area.

In other exemplary embodiment, pins and staples can be used instead of screws. Such pin or stapler fixtures can be pounded into the device. Other alternative fixture devices or bonding materials can be used to fixate the prosthesis.

In the exemplary embodiments, the muscle suture attachment can be within the spinous process. This perforation can be a single perforation, or in other embodiments, the prosthesis can include a plurality of perforations, or no perforations. The perforations are not limited to the locations illustrated in the exemplary embodiments and can be located anywhere on the prosthesis.

The exemplary embodiments, the prosthesis can be, for example, manufactured in multiple parts which can come in different sizes accommodating intra-patient and multiple patient anatomical variations, and the prosthesis can be assembled intra-operatively by the surgeon using multiple assembly techniques creating tailor made products individualized for the patient.

In another exemplary embodiment, the method can include selecting one or more appropriately sized prostheses from a set or kit of a plurality of prostheses, wherein the set or kit includes prosthesis having different standard sizes. The selected prosthesis each can have the same size or different sizes depending on the dimensions of the natural spinal portions of a given recipient.

The exemplary embodiments can include a current laminar prosthesis that is arch shaped to mimic the natural spinal, anatomy and to protect the intra-spinal neural elements. However other shapes can also be used which include, but at not limited to, circular, polygonal, pyramidal, flat, cornered, rounded, or any combination, variation, or permutation of the above.

It is intended that all such modifications and additions comprise a part of the present invention to the extent that they fall within the scope of the several claims appended hereto.

Like numbers refer to like elements throughout. In the figures, the thickness of certain lines, layers, components, elements or features may be exaggerated for clarity.