HK1190592B - Interspinous vertebral and lumbosacral stabilization devices and methods of use - Google Patents

Description

Interspinous vertebral and lumbosacral stabilization devices and methods of use

The present application is a divisional application filed on 7/4/2006 under the name of 200680020249.2 entitled "interspinous vertebral and lumbosacral stabilization device and method of use".

Cross Reference to Related Applications

This application claims priority from U.S. provisional application No.60/669,346, filed on 8/4/2005, the entire contents of which are incorporated herein by reference.

Technical Field

The present invention relates to devices and methods for treating spinal disorders, and in particular to spinal stabilization devices for stabilizing adjacent vertebrae and methods of using such devices. More particularly, the present invention relates to interspinous spinal stabilization devices for placement between the spinous processes of two or more vertebrae, and even more particularly, to lumbosacral stabilization devices for placement between the lumbar vertebrae and adjacent vertebrae, and methods of using these devices.

Background

Spinal diseases result in serious pathologies. These diseases include abnormalities of the spine, intervertebral discs, facet joints, and connective tissue surrounding the spine. These abnormalities may arise from a variety of causes, including mechanical injury or degenerative disc disease. These abnormalities can cause instability of the spine, cause the spine to become misaligned and create micromotion between adjacent vertebrae. Vertebral misalignment and micromotion can lead to wear of the vertebral bone surfaces and ultimately to severe pain. In addition, these diseases are often chronic and progressively aggravating problems.

Treatment for spinal disorders may include chronic medical treatment or surgery. Medical treatment is generally aimed at controlling conditions such as pain, rather than correcting underlying problems. For some patients, this may require the use of pain medication for extended periods of time, which may alter the patient's mental state or cause other adverse side effects.

Another treatment is surgery, which is often highly invasive and can significantly alter the anatomy and function of the spine. For example, surgical treatment for certain spinal disorders includes spinal fusion, in which two or more vertebrae may be joined using bone grafts and/or artificial implants. This fusion process is irreversible and may significantly alter the range of motion of the spine. In addition, existing surgical procedures are often only suitable for patients in a significantly advanced state.

Accordingly, spinal surgeons have begun to explore more advanced surgical methods and spinal stabilization and/or repair devices that are less invasive, potentially reversible, and do not significantly alter the patient's normal anatomy and spinal function. These methods may be used at an earlier stage of disease progression and may even stop or reverse the progression of the disease in some cases.

A variety of interspinous stabilization devices have recently been available. These devices may be implanted between the spinous processes of two or more adjacent vertebrae. By thus stabilizing the spinous processes, it is possible to remove a large pressure from the intervertebral disc to prevent the progress of a disease or to improve a disease such as spinal stenosis. In addition, spinal motion can be controlled without significantly altering the anatomy of the spine.

Prior interspinous vertebral implants are configured to attach to the spinous processes of two or more adjacent vertebrae. Since the sacrum has very little or no spinous process, these devices cannot be implanted between the fifth lumbar vertebra (L5) and the first sacral vertebra (S1). However, many patients suffer from spinal disorders that affect L5 and the sacral spine. It is therefore desirable to provide an interspinous spinal stabilization device that is implantable between the sacrum and the lumbar vertebrae.

Disclosure of Invention

The present invention includes interspinous vertebral and lumbosacral stabilization devices for treating spinal instability conditions, and methods of using these devices. The present invention includes an interspinous vertebral stabilization device adapted to be positioned between spinous processes of two or more adjacent vertebrae. The invention also includes lumbar stabilization devices adapted to be positioned between a lumbar vertebra and adjacent vertebrae, including a first sacral vertebra (S1), to stabilize the lumbosacral region of a patient, and methods of using these devices.

One aspect of the invention includes a device for stabilizing vertebrae adjacent or proximate to a sacrum. The device may include an implantable flexible U-shaped spacer body including an inferior portion, a superior portion, a medial portion, and a pair of lateral walls extending from the superior portion for engaging the spinous process of the lumbar vertebra. The device may also include an anchor assembly for securing the spacer body between the lumbar vertebra and adjacent vertebrae, including the sacrum.

A second aspect of the invention includes an interspinous stabilization device including a support rod and a flexible U-shaped spacer body. The spacer includes a lower portion, an upper portion, and a middle portion between the lower portion and the upper portion. A pair of lateral walls extend from the upper portion for engaging the spinous processes of the lumbar vertebrae. The lower portion may include a base configured to engage the support bar. The device may further include at least one fixation element for securing the support rod to adjacent vertebrae.

A third aspect of the invention includes a lumbosacral interspinous stabilization device that includes a flexible U-shaped spacer for implantation between a lumbar vertebra and a sacrum. The spacer includes a lower portion, an upper portion, and a middle portion between the lower portion and the upper portion. A pair of lateral walls extend from the upper portion for engaging the spinous processes of the lumbar vertebrae. The lower portion can include at least one projection forming a gripping portion for engagement with the sacrum.

A fourth aspect of the invention includes an implantable device for stabilizing an interspinous process region of a patient, the device comprising a flexible U-shaped spacer body having a lower portion, an upper portion, and a middle portion extending between the lower and upper portions. The device may also be provided with a retaining sleeve for engaging an upper portion of the spacer body. The sleeve is configured to secure a spinous process of a vertebra to the spacer body. An anchor assembly is also provided for securing the spacer body between the vertebra and an adjacent vertebra.

A fifth aspect of the invention includes an interspinous process vertebral stabilization device including a flexible U-shaped spacer body. The spacer includes a lower portion, an upper portion, and a middle portion between the lower portion and the upper portion. The spacer body may be configured to be positioned in an interspinous space between two adjacent vertebrae. The device may also be provided with a pair of securing sleeves, each sleeve configured to engage an upper or lower portion of the spacer body. When attached to the spacer body, the sleeve secures the spinous processes of two adjacent vertebrae to the spacer body.

A sixth aspect of the invention includes an interspinous process vertebral stabilization device including a flexible U-shaped spacer body. The spacer body includes an inferior portion including a pair of lateral walls extending therefrom for engaging a spinous process of a vertebra. The spacer body also includes an upper portion including a pair of lateral walls extending therefrom for engaging the spinous processes of the adjacent vertebrae. A middle portion extends between the lower portion and the upper portion. The spacer body may be configured to be positioned in an interspinous space between two adjacent vertebrae. The device may further include a pair of securing sleeves, each sleeve configured to engage the two pairs of lateral walls. When attached to the spacer body, the sleeve secures the spinous processes of the two adjacent vertebrae to the spacer body.

A seventh aspect of the invention includes an interspinous process vertebral stabilization device including a flexible U-shaped spacer body. The spacer body includes an inferior portion including a pair of lateral walls extending therefrom for engaging a spinous process of a vertebra. The spacer body also includes an upper portion including a pair of lateral walls extending therefrom for engaging the spinous processes of the adjacent vertebrae. A middle portion extends between the lower portion and the upper portion. At least one of the lateral walls is selectively movable relative to another of the lateral walls. The movable lateral wall is selectively positionable to secure the spinous process of one of the two adjacent vertebrae to the spacer body.

Methods of stabilizing the lumbosacral region of a patient using the devices of the present invention are also provided. Methods of using the devices of the invention to stabilize the interspinous region of adjacent vertebrae are also provided.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and together with the description, serve to explain the principles of the invention.

Additional objects and advantages of the invention will be set forth in part in the description which follows, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.

Drawings

Fig. 1 illustrates an exemplary embodiment of an interspinous, lumbosacral stabilization device in accordance with the present invention;

2A-2B illustrate side views of a spacer in a rest state (restingstate) and a compressed state, respectively, according to an exemplary disclosed embodiment;

3A-3C illustrate side views of a spacer body having a varying thickness along its length in accordance with a disclosed exemplary embodiment;

FIG. 4A shows a side view of a spacer having a variable width along its length according to another exemplary disclosed embodiment;

FIG. 4B shows a rear view of the spacer of FIG. 4A;

FIG. 5 illustrates a side view of a spacer body according to an exemplary disclosed embodiment;

6A-6C illustrate a rear view of a spacer body according to an exemplary disclosed embodiment;

FIG. 7A illustrates a rear view of a spacer including barbs, according to a disclosed exemplary embodiment;

FIG. 7B illustrates a side view of a spacer including barbs, according to a disclosed exemplary embodiment;

FIG. 8A illustrates a partial top perspective view of a spacer body including curved lateral walls in accordance with an exemplary disclosed embodiment;

FIG. 8B is an enlarged view showing a detail of FIG. 8A;

FIG. 9A illustrates a partial perspective view of a spacer body including curved lateral walls in accordance with an exemplary disclosed embodiment;

FIG. 9B shows a partial perspective view of the spacer body of FIG. 9A implanted in a patient;

FIG. 10A illustrates a partial perspective view of a spacer body having detachable lateral walls, according to an exemplary disclosed embodiment;

FIGS. 10B and 10C show partial perspective views of the spacer of FIG. 10A implanted in a patient;

FIG. 11A illustrates a partial perspective view of a spacer body having detachable lateral walls, according to an exemplary disclosed embodiment;

11B and 11C show partial perspective views of the spacer body of FIG. 11A implanted in a patient;

FIG. 12A illustrates a partial perspective view of a spacer body having detachable lateral walls, according to an exemplary disclosed embodiment;

12B and 12C show partial perspective views of the spacer of FIG. 12A implanted in a patient;

FIG. 13A illustrates a partial perspective view of a spacer body having hinged lateral walls in accordance with an exemplary disclosed embodiment;

FIGS. 13B and 13C show partial perspective views of the spacer of FIG. 13A implanted in a patient;

FIG. 14A shows a partially exploded view of a spacer body having a reversible lateral wall in accordance with an exemplary disclosed embodiment;

14B and 14C show partial perspective views of the spacer body of FIG. 14A implanted in a patient;

FIG. 14D is an enlarged view showing a detail of FIG. 14C;

FIG. 15 illustrates a side view of a bone fastener according to an exemplary disclosed embodiment;

FIG. 16A shows a cross-sectional view of the bone fastener of FIG. 16C, according to an exemplary disclosed embodiment;

FIG. 16B is an enlarged view showing a detail of FIG. 16A;

FIG. 16C shows a side view of the bone fastener of FIG. 16A;

FIG. 16D is an enlarged view showing a detail of FIG. 16C;

FIG. 17A illustrates a perspective view of a spacer body and a flexible mount according to an exemplary disclosed embodiment;

fig. 17B shows the device of fig. 17A disposed between the spinous process and sacrum of L5 in accordance with an exemplary disclosed embodiment;

FIG. 18A illustrates a partial perspective view of a spacer body having a rigid mount according to an exemplary disclosed embodiment;

FIG. 18B is an enlarged view showing a detail of FIG. 18A;

FIG. 18C shows a partial perspective view of the spacer of FIG. 18A implanted in a patient;

FIG. 19A illustrates a partial perspective view of a spacer body having a rigid mount according to an exemplary disclosed embodiment;

FIG. 19B is an enlarged view showing a detail of FIG. 19A;

FIG. 19C shows a partial perspective view of the spacer of FIG. 19A implanted in a patient;

FIG. 20A illustrates a partial perspective view of a spacer body having a rigid mount according to an exemplary disclosed embodiment;

FIG. 20B is an enlarged view showing a detail of FIG. 20A;

FIG. 20C shows a partial perspective view of the spacer of FIG. 20A implanted in a patient;

FIG. 21 illustrates a side view of a spacer body, according to an exemplary disclosed embodiment;

FIG. 22A illustrates a side perspective view of a spacer body according to another exemplary disclosed embodiment;

FIG. 22B shows a perspective view of the spacer of FIG. 22A implanted in a patient;

FIG. 23 illustrates a side view of a spacer body according to yet another exemplary disclosed embodiment;

fig. 24 illustrates a rear view of a spacer and a fixing bar according to an exemplary disclosed embodiment;

25A-25C illustrate cross-sectional views of a fixation rod according to an exemplary disclosed embodiment;

figure 26A shows a front view of a fixation rod according to another exemplary disclosed embodiment;

fig. 26B illustrates an exploded perspective view of the spacer and fixation rod of fig. 26A, according to an exemplary disclosed embodiment;

27A-27C illustrate front views of alternative fixation rods according to exemplary disclosed embodiments;

FIG. 28A illustrates a perspective view of a spacer in accordance with an exemplary disclosed embodiment;

FIG. 28B shows a perspective view of a device including the spacer body of FIG. 28A implanted in a patient;

FIG. 29A shows an exploded view of a spacer body and a rod according to an exemplary disclosed embodiment;

FIG. 29B shows a perspective view of an apparatus including the spacer and bar of FIG. 29A;

FIG. 29C shows a partial cross-sectional view of the device of FIG. 29B implanted in a patient;

FIG. 30 illustrates an exploded perspective view of a polyaxial screw (polyaxial screw) system, according to an exemplary disclosed embodiment;

FIG. 31A shows a cross-sectional view of the polyaxial screw system of FIG. 30 taken along line A-A;

FIG. 31B shows a cross-sectional view of the polyaxial screw system of FIG. 30 taken along line B-B;

FIG. 31C is an enlarged view showing a detail of FIG. 31A;

FIG. 31D is an enlarged view showing a detail of FIG. 31B;

FIG. 32A illustrates a side perspective view of a spacer body in accordance with an exemplary disclosed embodiment;

FIG. 32B shows a partial side perspective view of the spacer of FIG. 32A implanted in a patient;

FIG. 33A illustrates a side perspective view of a spacer body in accordance with an exemplary disclosed embodiment;

FIG. 33B shows a partial side perspective view of the spacer of FIG. 33A implanted in a patient;

FIG. 34A illustrates a side perspective view of a spacer body in accordance with an exemplary disclosed embodiment;

FIG. 34B shows a partial side perspective view of the spacer of FIG. 34A implanted in a patient;

FIG. 35A illustrates a side perspective view of a spacer body in accordance with an exemplary disclosed embodiment;

FIG. 35B shows a partial side perspective view of the spacer of FIG. 35A implanted in a patient;

FIG. 36A illustrates a side perspective view of a spacer body in accordance with an exemplary disclosed embodiment;

FIG. 36B shows a partial side perspective view of the spacer of FIG. 36A implanted in a patient;

FIG. 37A illustrates a side perspective view of a spacer body according to yet another exemplary disclosed embodiment;

FIG. 37B shows a partial side perspective view of the spacer body of FIG. 37A implanted in a patient;

FIG. 38A shows an exploded perspective view of a spacer in accordance with another exemplary disclosed embodiment;

FIG. 38B shows a side perspective view of the assembled spacer of FIG. 38A;

FIG. 39 shows a perspective view of the spacer of FIGS. 38A and 38B implanted in a patient;

FIG. 40A illustrates an exploded perspective view of a spacer body according to yet another exemplary disclosed embodiment;

FIG. 40B shows a side perspective view of the assembled spacer of FIG. 40A;

FIG. 41 shows a perspective view of the spacer body of FIGS. 40A and 40B implanted in a patient.

Detailed Description

The present disclosure provides implantable devices for stabilizing vertebrae when placed between spinous processes of adjacent vertebrae, and for stabilizing the lumbosacral region of a patient by being placed between a lumbar vertebra and adjacent vertebrae, including a first sacral vertebra (S1). As shown in the exemplary embodiment shown in fig. 1, the implant or device 10 includes a spacer body 12 configured to be implanted between a spinous process of a lumbar vertebra, such as the spinous process of the fifth lumbar vertebra (L5), and an adjacent vertebra. An anchor assembly 14 is provided to secure the spacer body 12 to an adjacent vertebra, which may be, for example, a first sacral vertebra (S1).

The anchor assembly 14 may include a support or fixation rod 16 to help maintain the spacer body 12 in position relative to the spine. One or more fixation elements, such as bone anchors 18, may be used to securely attach the support or fixation rod 16 to the sacrum of the patient. As shown in fig. 1, the spacer body 12 may be connected to the fixation rod 16 at a base 62. The spacer body 12, support rod 16 and bone anchor 18 collectively form an interspinous stabilization assembly for stabilizing a lumbar vertebra, such as the fifth lumbar vertebra adjacent the sacrum (L5).

The spacer 12 may have a variety of different shapes, thicknesses, and materials. In one embodiment, as shown in FIG. 1, the spacer body 12 may include a middle portion 30 extending between a lower portion 32 and an upper portion 34. When implanted in a patient, the upper portion 34 is configured to contact a portion of the spinous process, while the lower portion 32 is configured to connect with the fixation rod 16. In one embodiment, the central portion 30, the lower portion 32, and the upper portion 34 may collectively form a substantially U-shaped spacer body 12.

The spacer body 12 may be configured to be flexible and/or bendable, such as by providing an expandable and/or compressible midsection 30. During spinal extension, the spinous processes can exert a downward force on the upper portion 34. Likewise, during extension of the spinal column, the fixation rod 16 and/or the sacrum may exert an upward force on the lower portion 32. As shown in FIGS. 2A and 2B, these forces can cause the upper and lower portions 34 and 32 to become closer together (FIG. 2B) from a rest state (FIG. 2A) in which no external force is acting on the spacer body 12. Such compressibility enables the spacer body 12 to reversibly deform to allow a degree of spinal extension. Thus, the middle portion 30 acts as a flexible hinge such that the upper and lower portions 34, 32 can move away from or toward each other.

In addition, the thickness and physical properties of the upper and/or lower portions 34, 32 may be selected to allow the upper and/or lower portions 34, 32 to bend under large loads. Flexibility (i.e., stretchability and/or compressibility) allows the spacer body 12 to better respond to certain normal movements of the patient. For example, a spacer body 12 having limited compressibility may allow a degree of spinal extension while also controlling spinal flexion, rotation, and/or lateral bending.

The flexibility and/or compressibility of the spacer body 12 may be selected based on the physical constitution of the patient in which the device 10 is to be implanted, on the desired range of motion, and on various clinical factors. These clinical factors may include co-morbid (co-morbid), extent of disease, prior surgery, etc. For some patients, a very rigid spacer 12 may be required. For other patients, the surgeon may choose a spacer 12 that is more flexible and compressible.

The flexibility and/or compressibility of the spacer 12 can be controlled in a variety of ways. For example, the spacers 12 may be formed from a variety of different materials. In one embodiment, the spacer 12 may be formed of a single material. Alternatively, the spacer body 12 may comprise a combination of material(s) such that the material forming the central portion 30, lower portion 32, and upper portion 34 may be different, thereby providing different degrees of flexibility and/or compressibility to the various portions. The particular material comprising the various portions of the spacer body 12 may be selected according to the desired degree of flexibility and/or compressibility, or to provide biocompatibility and/or bioactive properties.

A variety of biocompatible materials are suitable for use in forming the disclosed spacer body 12. For example, in one embodiment, the spacer body 12 may be formed from a medical grade metal, such as titanium or a titanium alloy. The spacer 12 may also be formed of, for example, stainless steel, cobalt chrome, ceramic, and/or polymeric materials such as Ultra High Molecular Weight Polyethylene (UHMWPE) and Polyetheretherketone (PEEK), either alone or in combination with another suitable material.

Another way of providing flexibility and/or compressibility to the spacer body 12 is to vary the dimensions of the spacer body 12 such that the degree of flexibility is related to the relative dimensions of the spacer body 12. For example, the spacer 12 may have a plurality of different thicknesses along its length. The thickness may be selected to produce a desired degree of flexibility and compressibility. Further, the spacer 12 may have a variable thickness in one or more portions. FIGS. 3A-3C illustrate various thickness configurations of the spacer body 12, wherein the central portion 30 has a thickness t₁The lower portion 32 having a thickness t₂And the upper portion 34 has a thickness t₃. In one embodiment, the thickness t₁Thickness t₂And a thickness t₃May be substantially equal (fig. 3A). In another embodiment, the thickness t₁Can be greater than the thickness t₂And t₃(FIG. 3B), in yet another embodiment, the thickness t₁Can be less than the thickness t₂And t₃(FIG. 3C). Thus, as shown in fig. 3B and 3C, the thickness of the spacer 12, and thus its flexibility, may vary along its length.

Yet another way to affect the flexibility of the spacer 12 is to vary its width along the length of the spacer 12. For example, as shown in FIG. 4A, the spacer 12 may have a width at the central portion 30 that is less than the width at the lower portion 32 or the upper portion 34. Such a configuration would impart an hourglass-like configuration to the spacer body 12 when viewed from the rear, as shown in fig. 4B.

To limit compression of the central portion 30 of the spacer body 12, it is contemplated that a support pad (not shown) may be disposed within the spacer body 12 between the upper portion 34 and the lower portion 32. The support pad may be similar to that described in U.S. Pat. No.5,645,599 to Samani, the contents of which are incorporated herein by reference in their entirety. The support pads limit the mutual closing of the two portions 32, 34 and ensure, if necessary, an auxiliary cushioning of the vertebrae 4. The pad may be made of a suitable resilient material, either a fabric material or a synthetic material, and may be secured to the portions 32, 34 by suitable means, such as by gluing.

To engage the spinous processes of the vertebrae, the spacer body 12 can have a pair of lateral walls or brackets 36 extending from the upper portion 34, as shown in fig. 5. The pair of lateral walls 36 define a clamp 38 for receiving the spinous processes. In one embodiment, the lateral wall or bracket 36 can be configured to engage a spinous process of a lumbar vertebra adjacent the sacrum and secure the spacer body 12 thereto. For example, the stent 36 may be configured to engage a spinous process of a fifth lumbar vertebra (L5) adjacent the sacrum.

The lateral wall 36 may have a plurality of orientations relative to the spacer body 12. For example, as shown in fig. 6A-6C, the lateral walls 36 may extend at various angles relative to the upper portion 34. In one embodiment, the lateral walls 36 may form a 90 degree angle with respect to the upper portion 34 (fig. 6A). In other embodiments, the lateral walls 36 may form an obtuse angle (fig. 6B) or an acute angle (fig. 6C) with respect to the upper portion 34. In addition, the spacer body 12 may have lateral walls 36 of different sizes or heights to accommodate a variety of different interspinous spaces between the vertebrae. Likewise, the lateral walls 36 of different spacer bodies 12 may be disposed at different locations along the length of the upper portion 34 to provide a wider variety of sizes and shapes. In this manner, the surgeon may select a spacer body 12 having an appropriate shape and size depending on the particular vertebra to be supported and the patient's natural anatomy.

In addition, the lateral wall 36 may also be adjustable relative to the spacer body 12. For example, in one embodiment, the lateral walls 36 may form an obtuse angle with respect to the upper portion 34 prior to implantation. The lateral walls 36 may be made of a malleable material so that after implantation the surgeon may compress the lateral walls 36 together to reduce the gap between the lateral walls 36 to securely fix the spacer body 12 to the spinous processes of the vertebrae. The compression may be accomplished, for example, by pinching or squeezing lateral walls 36 toward one another using forceps or tweezers.

To further enhance the ability of the device 10 to fasten to the surrounding bone and soft tissue after implantation, the device 10 may include a number of surface modifications. For example, portions of the spacer body 12, the lateral walls 36, the anchors 18, and/or the fixation rod 16 may include surface variations that facilitate tissue attachment, integration, or fixation. These variations may include surface teeth, barbs, flanges, surface roughening, or the addition of bioactive agents to one or more portions of the device 10. For example, the device 10 may include one or more barbs 40 for securing the device 10 to bone and/or soft tissue. As shown in fig. 7A and 7B, the barbs 40 may be located on the spacer body 12, such as on the outer surface of the intermediate, lower and/or upper portions 30, 32, 34 (fig. 7B). Alternatively or additionally, the barbs 40 may be located on the inner surface of the lateral wall 36 (fig. 7A). The barbs 40 can help securely engage the spacer body 12 to connective tissue or bony surfaces of a vertebra, such as the spinous process of a vertebra.

In addition, the device 10 may also include a roughened or porous surface. A rough or porous surface may enhance the connection between the implant surface and the bone tissue. In addition, certain porous surfaces may promote tissue ingrowth to form a biological bond between portions of the device 10 and the surrounding bone and/or soft tissue. A roughened or porous surface may be included on any portion of the device 10, including the spacer 12, the anchor 18, the lateral wall 36, and/or the fixation rod 16.

The surface of the device 10 may also include a bioactive agent. These agents may include osteogenic factors to further promote bonding between the components of the device 10 and the surrounding bone and/or soft tissue. In addition, the device 10 may include therapeutic agents, such as antibiotics, steroids, anti-thrombotic agents, anti-inflammatory agents, and/or analgesics. In one embodiment, the bioactive agent may be contained within a coating on the device. Alternatively or additionally, the device may be porous and the bioactive agent may be contained within the pores of the device. The bioactive agent may, for example, be a Bone Morphogenetic Protein (BMP) for promoting cartilage or bone growth.

To further enhance fixation of the spinous processes within the clamp 38 defined by the lateral wall 36 of the spacer body 12, the lateral wall 36 may be curved or angled relative to the longitudinal axis L of the spacer body 12. For example, fig. 8A and 8B illustrate the lateral wall 36 being curved away from the longitudinal axis L of the spacing body 12 along the length of the lateral wall 36. The lateral walls or braces 36 may also be curved or bent inwardly or outwardly along their length relative to the longitudinal axis L of the spacer body 12 to accommodate the natural anatomical curvature of the patient's tissue lamina (laminae). Fig. 9A shows the spacer body 12 having lateral walls 36 that are curved inwardly relative to the longitudinal axis L of the spacer body 12. As shown in fig. 9B, the bracket 36 thus curved allows greater compliance around the spinous process 2 and thus better fixation of the device 10 to the vertebra 4.

In another exemplary embodiment, at least one of the lateral walls or brackets 36 can be removably attached to the spacer body 12. For example, as shown in FIGS. 10A-10C, one of a pair of lateral walls or brackets 36A may be in the form of an element attachable to the spacer body 12, while the other lateral wall or bracket 36B is permanently fixed to or integral with the spacer body 12. The attachable support 36B may include a first free end 42 and an opposing second attachment end 44 shaped complementary to a slot or groove 46 on the upper portion 34, thereby forming a secure connection with the spacer body 12.

As shown in Figs. 10A-10C, the attachment end 44 may be formed as a flared end or dovetail for sliding engagement with the dovetail slot 46 on the upper portion 34 when the spacer body 12 is implanted in position. Fig. 11A-11C show an attachable support 36A having an attachment end 44 shaped as a "T" for sliding engagement with a T-shaped slot 46 on the upper portion 34 of the spacer body 12. Further, in addition to the channel 46 being slidably attached to the top surface of the spacer body's upper portion 34, the attachable support 36A may also be slid into the channel 46 formed on the side surface of the upper portion 34. For example, as shown in FIGS. 12A-12C, the attachment end 44 of the bracket 36A is configured as a dovetail for sliding engagement with a dovetail slot 46 on the side of the upper portion 34 of the spacer body 12. Although the attachment end 44 is described above as having a dovetail or T-shaped configuration, it should be understood that the attachment end 44 may include other shapes known to those skilled in the art for forming a secure connection with a complementary shaped groove 46 on the upper portion 34.

In yet another embodiment, rather than having a freely detachable bracket 36A, the spacing body 12 may include a movable, pivotable bracket 36A that is hingeable with the upper portion 34. For example, as shown in fig. 13A-13C, the second attachment end 46 of the bracket 36A can include an aperture 48 through which a pin 50 can be disposed to pivotally secure the bracket 36A to the side of the upper portion 34. In this embodiment, the pivotable support 36A can be folded down prior to implantation (fig. 13A), and then the pivotable support 36A can be folded up against and engage the spinous process 2 of the vertebra 4 after the spacer body 12 is placed in the correct position, as shown in fig. 13B and 13C.

In yet another embodiment, as shown in FIG. 14A, a movable adjustable bracket 36A may be hingedly connected to the upper portion 34 of the spacer body. In this embodiment, the movable bracket 36A may be attached to the spacer body 12 by a hinged joint 52 that allows the bracket 36A to be folded up and down. This invertibility allows movement of the bracket 36A between a position in which the movable bracket 36A is substantially perpendicular to the corresponding adjacent bracket 36B (fig. 14A) and a position in which the movable bracket 36A is substantially parallel to the adjacent bracket 36B to engage the spinous process 2 (fig. 14B and 14C).

The lateral wall or bracket 36 of the present invention may also include holes 60 for receiving bone screws, fasteners or rivets that secure the bracket 36 to the spinous process 2. These fastening means ensure that the support 36 lies flat against the spinous processes 2 to avoid gaps of the spinous processes with respect to the support 36. For example, as shown in fig. 14B-14C, each bracket 36A, 36B may have an aperture 60 configured to receive a rivet or fastener 100 shown in more detail in fig. 15. The rivet 100 may include a cap portion 102 and an elongate body 104 extending from the cap portion 102, the elongate body 104 including a plurality of teeth 108 and terminating in a tapered tip 106. The elongated body 104 is configured to extend between the apertures 60 of the brackets 36A, 36B. A washer 120 may be provided to retain rivet 100 within hole 60. As shown in fig. 14C and in more detail in fig. 14D, the washer 120 includes a hole 122 for receiving the tapered end 106 of the rivet 100. The slit 124 around the hole 122 allows the washer 120 to bend so that the tapered end 106 can be pushed through the hole 122 and the washer 120 to close around the teeth 108 of the rivet 100.

Fig. 16A-16D illustrate another exemplary embodiment of a bone fastener or pin 140 suitable for use with the bracket 36 of the present invention. The fastener 140 includes a head 142 and an elongated body 144, the elongated body 144 having teeth 148 extending therearound to a tip 146. To secure the fastener 140 between the holes 60, a cap 160 is provided having a head 162 and a body 164 extending therefrom for receiving the tip 146 of the fastener 140. As shown in more detail in fig. 16D, the hollow body 164 may include one or more U-shaped slits 166, each slit 166 defining a finger tab 168 therein. As shown in fig. 16A and in more detail in fig. 16B, each finger tab 168 has a curved tip 170 that bends toward the central axis of the hollow body 164 to engage the teeth 148 of the fastener 140. In one exemplary embodiment, the cap 160 includes two pairs of finger-like projections 168, each pair diametrically opposed. The pair of finger-like projections 168 may be offset relative to the longitudinal axis A-A of the cap 160 to provide a more controlled level of connection by providing two distinct areas within the slotted cavity 166 for catching the teeth 148 of the fastener 140. In use, the cap 160 is passed through the aperture 60 of the bracket 36 and then pushed toward the fastener 140 in a ratchet-like manner until the heads 142, 162 of the fastener 140 and cap 160 abut the outer surface of the bracket 36, locking the fastener 140 and cap 160 together, thereby also providing a generally smooth outer surface that prevents damage or injury to adjacent soft or bony tissue.

It is also contemplated that the bracket 36 of the spacer body 12 may be used with one or more flexible fixation elements to further secure the device 10 to one or more spinous processes. In one embodiment shown in fig. 17A, the lateral wall or shelf 36 of the flexible spacer body 12 may include one or more holes 60 for attachment of a flexible fixation element 180. The flexible fixation element 180 may comprise a man-made material or a natural material. For example, flexible fixation element 180 may include any type of synthetic or natural suture material. The flexible fixation elements 180 may also include grafts of ligaments, tendons, fascia, or muscles, and the grafts may include autografts, allografts, or xenografts having sufficient strength and flexibility to be tied to the spinous processes of vertebrae, such as lumbar vertebrae. Alternatively, the flexible fixation element may be a fabric, mesh, or band, such as a cable-binder type band, that is placed around the spinous processes.

Fig. 17B shows the spacer body 12 implanted between the sacrum 8 and the spinous process 2 of an adjacent vertebra 4 with the fixation rod 16 secured to the sacrum 8 using two anchors 18. The lateral wall 36 also secures the spacer body 12 to the spinous process 2 of the spine. In addition, the device 10 includes a flexible fixation element 180 that can further secure the device 10 to the spinous process 2.

In yet another embodiment, as shown in fig. 18A-18C and 19A-19C, the spacer body can be secured to the spinous processes using a rigid fixation element. As shown in fig. 18A and 18B, a stabilization device 200 is provided that may include a rigid fixation element including a rigid fixation sleeve 220 positioned over a portion of the spacer body 202. Spacer body 202 may be similar to spacer body 12 but without lateral walls 36. As shown in fig. 18C, the harness 220 can be U-shaped and include a pair of side walls 222, the terminal ends 224 of the side walls 222 including lips 226 defining grooves 228 that slidingly engage the flanges 206 on the upper portion 204 of the spacer body 202 to securely attach the spacer body 202 to the spinous process 2. The fixation sleeve 220 can include barbs 210 that securely engage the bony surfaces of the spinous process to ensure rigid fixation.

Fig. 19A-19C illustrate another exemplary embodiment in which a stabilization device 240 has a rigid fixation element that includes a fixation sleeve 260 disposed over a portion of a spacer body 242. The harness 260 may be U-shaped and includes a pair of side walls 262, with the terminal ends 264 of the side walls 262 including beveled flanges 266. Like spacer 202, spacer 242 does not include lateral walls 36. Rather, the spacer body 242 may include a groove 246 on the upper portion 244. Due to the slight flexibility and compressibility of the sidewalls 262, as shown in fig. 19A and 19B, the angled flanges 266 may be forced downward and through the slots 246 to engage the spacers 242. The harness 260 can include barbs 210 that securely engage the bony face of the spinous process to ensure rigid fixation.

Fig. 20A-20C illustrate an exemplary embodiment of the spacer 12 of the present invention that may be used with a rigid fixation element. As shown in fig. 20A and 20B, a rigid retainer sleeve 280 is provided for use with the spacer body 12 of the present invention. Rigid harness 280 includes a pair of side walls 282 connected by a connecting portion 284. The side walls 282 include teeth 288 on an inner surface that are engageable with ratchet teeth (notch)64 on a lateral wall of the spacer body 12 or an outer surface of the bracket 36. In use, the fixation sleeve 280 can be placed over the bracket 36 after the spacer body 12 is in place and the spinous process 2 of a vertebra is securely positioned within the jaws 38 defined by the bracket 36. By pushing the fixation sleeve 280 downwards, the teeth 288 in the side walls 282 can snap (ratchet over) and lock the ratchet teeth 64 of the stent 36 until the connection 284 of the fixation sleeve 280 rests against the spinous process 2, thereby ensuring a secure fit between the bony tissue and the device 10, as shown in fig. 20C. The adjustability of the fixation sleeve 280 allows the spacer body 12 to secure spinous processes of various sizes. As shown, the lateral wall or bracket 36 may have an elongated slot 60 similar to the elongated slot 290 on the side wall 282 of the securing sleeve 280. When the fixation sleeve 280 is snapped onto the spacer body 12, the slots 60, 290 align and cooperate to provide an opening through which an optional fixation element can be passed to further secure the spinous process to the spacer body 12, if desired. The fixation elements may be, for example, bolts or bone screws that extend through or atop the spinous processes and through the two side walls 282.

The harness 220, 260, 280 may be formed from a variety of different biocompatible metallic materials such as titanium and stainless steel or cobalt chrome alloys or biocompatible plastics, either alone or in combination with at least one other suitable material within the group. The shape, size and material of the harness 220, 260, 280 may be selected to control their physical properties, such as flexibility, strength and/or resistance to fracture.

Turning now to the details of the anchor assembly 14 and the method for securing the spacer body 12 to the sacrum, as shown in fig. 21, the spacer body 12 may be connected with a fixation rod 16 at a base 62 extending from the lower portion 32. The base 62 may be permanently attached or removably attached. As shown in fig. 21, the spacer body 12 may include a hole 64 in the base 62 for engaging the fixation rod 16. In one embodiment, the holes 64 may be through holes through which the fixation rods 16 are disposed. A plastic liner may be provided within the aperture 64 of the base 62 to facilitate smooth sliding of the rod 16 within the aperture 64. The plastic liner may be formed, for example, from polyethylene, such as Ultra High Molecular Weight Polyethylene (UHMWPE) or Polyetheretherketone (PEEK).

In another embodiment, as shown in fig. 22A and 22B, the base 62 may include a semi-circular or C-shaped portion 66 for engaging the fixation rod 16. The C-shaped portion 66 may be configured to snap-fit onto the stem 16. It is contemplated that a plastic liner, for example formed of polyethylene such as Ultra High Molecular Weight Polyethylene (UHMWPE) or Polyetheretherketone (PEEK), may be provided on the stem 16 between the C-shaped portion 66 to allow the spacer body 12 to slide smoothly relative to the stem 16.

Further, the spacer body 12 may be configured to be rotatable at an angle relative to the longitudinal axis of the fixation rod 16. In one embodiment, the spacer body 12 is freely rotatable relative to the longitudinal axis of the fixation rod 16. In another embodiment, as shown in FIG. 23, the fixation rod 16 may include one or more protrusions 68 for limiting rotation of the spacer body 12. For example, where the projections 68 define a space in which the spacer body 12 is rotatable, the spacer body 12 may be rotated between about 0 degrees to about 60 degrees. Such rotation may facilitate positioning of the spacer body 12 during implantation, while also allowing a degree of control over the patient's motion after implantation. It is contemplated that the surgeon may select the degree of rotation available by selecting a fixation rod 16 with a protrusion 68 having a predetermined size and shape. Alternatively, the spacer 12 may be rigidly fixed to the fixation rod 16 without any rotation.

To provide greater flexibility in the orientation of the device 10, the spacer body 12 may also be configured to move or slide laterally/laterally relative to the fixation rod 16 during or after implantation. As shown in fig. 24, the fixation rod 16 may include one or more lateral protrusions 70 to define a space in which the spacer body 12 may slide. In this way, the lateral projections 70 may limit lateral displacement of the spacer body 12 when attached to the fixation rod 16. In one embodiment, the lateral projections 70 can be adjustably positioned on the fixation rod 16 so that the surgeon can select a desired degree of lateral displacement. Further, in one embodiment, the lateral projections 70 may be disposed proximate the spacer body 12 to prevent any lateral movement of the spacer body 12 relative to the securing bar 16. Alternatively, the securing bar 16 may be configured to limit lateral movement of the spacer body 12 (as shown in fig. 26A and 26B).

Turning now specifically to the fixation rod 16, the fixation rod 16 may be configured to have a variety of different shapes, sizes, and/or material properties. In the embodiment of fig. 1, the fixation rod 16 is a straight rod having a circular cross-section. Figures 25A-25C illustrate other cross-sectional geometries suitable for the fixation rod 16 of the present disclosure. For example, the fixation rod 16 may have an oval cross-section (fig. 25A), a square cross-section (fig. 25B), or a rectangular cross-section (fig. 25C).

Further, the fixation rod 16 may have a variable cross-sectional geometry along its length. For example, as shown in fig. 26A, the fixation rod 16 may include a connection region 74 for engaging the base 62 of the spacer body 12. The connecting region 74 may be thicker or thinner than the thicker portion 76 of the surrounding fixation rod 16 (as shown in fig. 26A and 26B).

In one embodiment, the securing bar 16 may be configured to limit lateral movement of the spacer body 12. For example, as shown in fig. 26B, the fixation rod 16 may include a narrow connection region 74. During manufacture, the fixation rod 16 may be connected to the spacer body 12 at the narrow connection region 74 by engaging the base 62 through the aperture 64. The surrounding thicker portion 76 may thereby resist lateral movement of the spacer body on the fixation rod 16 while still allowing the spacer body 12 to rotate relative to the fixation rod 16. Alternatively or additionally, the spacer 12 may be fused to the fixation rod 16 to prevent lateral movement and/or rotation relative to the fixation rod 16.

Like the spacer 12, the fixation rod 16 may be formed from a variety of different biocompatible materials. For example, the fixation rod 16 may be formed of, for example, titanium, stainless steel, ceramic, or cobalt-chromium alloy, either alone or in combination with at least one other suitable material within the group. The fixation rods 16 may comprise the same or different material as the spacer body 12. The shape, size, and material of the fixation rod 16 may be selected to control the flexibility, strength, and/or resistance to fracture of the fixation rod 16. The length and thickness may also be selected according to the (size) size, the nature of the disease and/or the activity level of the patient.

As shown in fig. 27A-27C, the fixation rod 16 may be straight, curved, or curvilinear along its length to conform to the natural curve of the patient's anatomy. For example, in one embodiment, the fixation rod 16 may include at least one curved portion 80 (fig. 27A). In another embodiment, the fixation rod 16 may include at least two bent portions 78 (fig. 27B). The bent portion 78 may form an angle a with respect to the longitudinal axis of the fixation rod 16. The angle a may be between 0 and 90 degrees. For example, the angle a may be about 30 degrees (fig. 27B) or about 90 degrees (fig. 27C).

In use, a fixation rod 16 having a curved portion 80 or bent portion 78 can be implanted in a variety of different anatomical orientations. For example, the bent portion 78 may be disposed in a superior-anterior (superior-anterior) orientation relative to a longitudinal axis of the fixation rod 16. The exact orientation may be selected based on surgical factors and/or the anatomy of the patient.

In some instances, it may be desirable to provide a spacer body 12' that is not only laterally slidable, but also slidable in the anterior-posterior direction. Fig. 28A and 28B provide such an exemplary embodiment, wherein the spacer body 12' includes an elongated or oval base 84 with a corresponding elongated or oval aperture 86 for the cylindrical stem 16 of the present invention. In all other respects, the spacer body 12' is similar to the spacer body 12 described previously, with similar features being indicated by the same reference numerals. To facilitate smooth sliding between base 84 and rod 16, a plastic liner 88 may be disposed within bore 86. The plastic liner may be formed from any suitable plastic, such as Ultra High Molecular Weight Polyethylene (UHMWPE) or Polyetheretherketone (PEEK). The elongated base portion 84 provides sufficient clearance for the spacer body 12 to slide back in the anterior-posterior direction during flexion and extension of the spinal column when implanted in a patient.

Fig. 29A to 29C show another exemplary embodiment 12 "of a spacer body movable about the front-side direction with respect to the fixing bar 16". As shown in FIG. 29A, the spacing body 12 "includes a lower portion 32 having a boss 90, the boss 90 defining a spherical recess or cavity 92 thereunder. The spherical cavity 92 is configured to seat against a spherical protrusion or bulge 94 on the fixation rod 16 ". In all other respects, the spacer body 12 "and the securing bar 16" are similar to the spacer body 12 and securing bar 16 described above, with similar features being identified with the same reference numerals. In use, the boss 90 seats and seats against the spherical protrusion or bulge 94, thereby forming a ball and socket type joint. Such a connection allows the spacer body 12 "to rotate freely relative to the rod 16", thereby providing the patient with greater flexibility and degree of motion, particularly in torsional or bending motions, while still providing a rigid, fixed connection to the supported vertebrae.

To secure the fixation rod 16 to the surface of the sacrum or other bone of the patient, a fixation element may be provided. The fixation elements may include anchors 18 attached to the fixation rod 16 at one or more anchor connection areas 110. As shown in fig. 30, the anchor connection area 110 may include a protrusion. Further, as shown in fig. 22B, the anchor connection region 110 may include indentations, concavities, convexities, or anchor through-holes. The design of the anchor connection area 110 may be selected based on the design of the particular type of anchor 18 used. It is contemplated that the design and type of anchor 18 may vary without departing from the spirit of the present invention. For example, the anchor 18 may comprise any type of screw capable of securely engaging bone.

Turning now to the details of the fixation element or anchor 18 shown in fig. 1, the anchor 18 may comprise a polyaxial screw that is adjustable through a range of angular orientations relative to the fixation rod 16. In this way, the polyaxial screw allows the surgeon to easily adjust the position of the screw, and thus the fixation rod 16, during surgery based on anatomical differences of the patient.

In one exemplary embodiment, the anchor 18 may be similar to that disclosed in U.S. patent No.6,554,831 to Rivard, which is incorporated herein by reference in its entirety. As shown in fig. 1 and 26B, polyaxial screw 20 is captured within a C-shaped collar, such as a snap collar 22, that fits around fixation rod 16. The screw 20 may include a proximal threaded portion 24 that extends through the collar 22 and is secured in place by a fastening nut 26, and a distal threaded portion 28 that enables the screw 20 to be anchored to bone tissue.

Of course, it should be understood that a variety of different designs of polyaxial screws may be used with the present invention to enable a surgeon to effectively secure the fixation rod 16 to a patient. An exemplary embodiment 300 of a polyaxial screw suitable for use with the present invention is shown in fig. 30, 31A and 31B. As shown, polyaxial screw 300 includes an elongated threaded body 302 extending between a head 304 and a tip 306. The threaded body 302 may be straight or angled/slanted or curved, depending on the particular needs of the patient. The head 304 includes a hollow spherical cavity 308 for receiving an anchor linkage element, in this embodiment in the form of a spherical clamp ring 320. The spherical clip 320 includes slits 322 distributed along its outer circumference to allow the clip 320 to flex and slidably fit over the fixation rod 16.

The head 304 further comprises a plurality of spherical recesses 328 creating curved inclined walls, and a groove 326 extending within the head 304 at the bottom of the cavity 308, the groove 326 being arranged to lie substantially radially of the cavity 308. These grooves 326 and recesses 328 converge toward each other in the direction of the bottom of the cavity 308 and impart slight flexibility to the head 304. In addition, the recess 328 allows the slotted spherical clamp ring 320 to snap into the hollow spherical cavity 308. Two threaded holes 330 are also provided in the head 304 to receive screws 318.

There is a locking cap 310 including a threaded hole 312 for receiving a screw 318. The threaded bore 312 is aligned with the bore 330 on the head 304. As shown in fig. 31A, the locking cap 310 also includes a cavity 314 suitably shaped to receive a portion of a spherical clamp ring 320. For example, the cavity 314 may have a tapered shape such that the cap 310 may contact the spherical clamp ring 320 during tightening of the screw 318. The cavity 314 may also include side recesses and grooves similar to those found in the spherical cavity 308 of the head 304 to allow the screw 300 to be angularly adjusted before being locked, as shown in fig. 31B.

In use, the spherical clip 320 is snap-fitted into the cavity 308 of the head 304 of the screw 300, the clip 320 being retained by engagement of the slot 322 of the clip 320 with the recess 328 of the head 304. The clamp ring 320 with the head 304 and threaded body 302 is then slid over the fixation rod 16 and positioned at the anchoring attachment area of the rod 16. The cap 310 is then placed over the clamping ring 320 and the screws 318 are passed through the threaded holes 312, 330 and tightened. The entire process may be repeated as multiple screws 300 may be used for any given fixation rod 16 depending on the needs of the patient.

In fig. 29B, a similar polyaxial screw 340 is shown, but with a modified head 344. Like the previously described polyaxial screw 300, polyaxial screw 340 includes an elongated threaded body 342 extending between a head 344 and a tip 346. The threaded body 342 may be straight or angled or curved, depending on the particular needs of the patient. The head 344 includes a hollow spherical cavity 348 for receiving an anchor connecting element such as the spherical clamp ring 320 shown in FIG. 30. As with the previous embodiments, the head 344 may include a plurality of spherical recesses 352 that create curved sloped walls, and a groove 350 that extends within the head 344 at the bottom of the cavity 348. Threaded bores 354 are also provided in the head 344 for receiving screws 370. At the opposite end of head 344 is a projecting flange 356 that creates a groove 358 for slidably receiving locking cap 360, as shown in fig. 29B and 29C.

The locking cap 360 has a lip 372 at one end and a single threaded hole 362 at the opposite end for receiving a screw 370. The threaded bore 362 is aligned with the bore 354 on the head 344. The lip 372 allows the cap 360 to slide over the head 344 and engage the groove 358 prior to insertion of the screw 370. Lip 372 of locking cap 360 and corresponding groove 358 of head 344 may be configured to provide a slight clearance or gap sufficient to enable locking cap 360 to be flipped up to approximately a 90 degree angle relative to head 344 without dislodging, thereby creating a hinge between cap 360 and head 344. Alternatively, the locking cap may be configured to attach to the head via a hinged joint. Furthermore, as with the previous embodiments, locking cap 360 may also include a cavity 364 suitably shaped to receive a portion of anchor connecting element 110, which cavity 364 may also include similar side recesses and grooves as present in locking cap 310.

Another exemplary embodiment 380 of a polyaxial screw suitable for use with the device 10 of the present invention is shown in fig. 22B and 28B. In these embodiments, the fixation rod 16 may be attached at both ends to a plate 390, the plate 390 having a spherical counterbore 392 with a through hole for insertion of the multi-axial screw 380. The plate 390 may clip onto the lever 16 or may be configured with an aperture for sliding engagement of the lever 16 into the plate 390 itself. The multi-axial screw 380 includes an elongated threaded body 382 extending from a spherical head 384 to a tip 388. The spherical head 384 includes a hexagonal opening 386 for receiving an insertion tool (not shown). In use, the spherical head 384 of the polyaxial screw 380 may be angularly adjusted within the spherical counterbore 392 of the plate 390 prior to fixation to bone tissue.

While a rod-based system for anchoring the spacer 12 to the sacrum or other bony tissue has been described, fig. 32A-41 provide other exemplary embodiments of the spacer that do not require a rod to attach to the sacrum. In fig. 32A, the spacer 400 is shown having similar features to the spacer 12 of the previous embodiment, wherein like features are indicated with like reference numerals. The spacer body 400 includes a pair of angled legs 402 extending from the lower portion 32 of the spacer body 400. The legs 402 lie in a plane substantially parallel to the plane containing the scaffold 36 and may include surface features, such as barbs 404, for engaging bone tissue. The legs 402 collectively form a portion of the anchor assembly 406 that includes a gripping portion 416 for connection to the sacrum. Optionally, a back plate 410 may be provided that extends from the lower portion 32 and lies in a plane that intersects the plane containing the support 36. In use, as shown in fig. 32B, the legs 402 are configured to rest against the middle crest (media crist) of the sacrum 8, while the backboard 410 is positioned within the sacral canal and against the sacrum 8. Thus, the legs 402 and the back plate 410 provide a passive bone engaging region that allows the spacer body 400 to be inserted and secured over the sacrum without injury or injury to the bone due to screw fixation.

In fig. 33A, spacer body 400' is shown with anchor assembly 406, anchor assembly 406 including two back plates 410 that extend angularly away from each other from lower portion 32. Each back plate 410 may also be slightly curved along its longitudinal axis. As shown in fig. 33B, in use, the spacer 400' rests on the sacrum such that the two back plates 410 rest on the sacrum inside the sacral canal and the legs 402 hook over the middle crest of the sacrum 8. The two back plates 410 are configured to provide sufficient clearance therebetween to avoid them touching any neural tissue contained within the sacral canal when inserted therein.

The spacer body 420 of fig. 34A includes an anchor assembly 406 that includes a peg 422 extending from the lower portion 32 at an angle generally parallel to the leg 402 without the back plate 410. As shown, the spikes 422 may have sharp tips. In use, the staples 422 are configured to penetrate the sacral tissue while the prongs 402 engage the middle crest, thereby positioning the spacer body 420 in position against the sacrum, as shown in fig. 34B. Although the legs 402 of the presently described embodiment(s) are shown as plates extending from the spacer body, it is contemplated that the legs 402 may also include hooks, barbs, claws, or any suitable gripping elements.

Fig. 35A and 35B illustrate yet another exemplary embodiment 440 of a spacing body that includes an anchor assembly 406, the anchor assembly 406 including a pair of end plates 432 extending from the lower portion 32 of the spacing body 440, each end plate 432 having a threaded bore 434 through which a screw 436 is inserted. In use, the end plate 432 can be placed between the sacral canal and the outer surface of the sacrum, with screws 436 passing through the bony tissue and through the end plate 432 secured with nuts 438. It is contemplated that more than one screw 436 may be used in this embodiment. For example, the end plate 432 may be configured to allow two or more screws 436 to be positioned in any suitable orientation relative to each other, such as in a horizontal row or a longitudinal row. Alternatively, two or more screws 436 can be inserted through the end plate 432 such that the screws 436 are positioned on the sides of the crest in the sacrum. In one embodiment, the spacer body 440 can have two pairs of end plates 432, each pair configured to clip over a portion of the sacrum that flank the crest in the sacrum. Of course, the end plate 432 may have any suitable number of threaded holes for insertion of bone screws 436 therethrough. These embodiments can rigidly and securely fix the spacer 440 to the sacrum.

36A and 36B illustrate an embodiment in which spacing body 450 includes a single end plate 452, rather than having two end plates 432, the single end plate 452 extending at an angle of approximately 90 degrees relative to the lower portion 32 of spacing body 450. As shown, the end plate 452 may include a barb 404 and a plurality of threaded holes 454 through which screws 456 pass. The end plate 452 may be configured to have a generally U-shaped body and one or more pairs of threaded holes 454 extending along the length of each leg of the U. The opening provided by the U-shape allows the end plate 452 to receive the spinous process, thereby avoiding the need to resect any portion of the bony tissue. Of course, it should be understood that the end plate 452 can take any shape and/or size suitable for placement on the sacral surface, and that any number of screws 456 can be used to achieve a rigid and secure fixation on the bony tissue. In use, as shown in fig. 36B, when the spacer body 450 is in place within a patient's body, the end plate 452 can be configured to rest against an outer surface of the sacrum 8.

Fig. 37A and 37B illustrate another exemplary embodiment in which the spacer body 450' has a removable end plate 452. The spacing body 450' has a shape similar to that shown in fig. 22A, with the base 62 having a C-shaped claw 66 that snap fits over the rod-like attachment end 460 of the removable end plate 452. This configuration enables the end plate 452 to rotate relative to the spacer body 450', thereby providing flexibility to the surgeon during implantation. A plastic gasket, for example formed of polyethylene such as Ultra High Molecular Weight Polyethylene (UHMWPE) or Polyetheretherketone (PEEK), may be provided between the rod-like attachment end 460 and the C-shaped portion 66 to facilitate smooth sliding of the spacer body 12 on the plate 452.

Fig. 38A and 38B illustrate such an exemplary embodiment, wherein a spacer 500 may include a middle portion 30, a lower portion 32, and an upper portion 34, and lateral walls or braces 36, similar to the spacers described and illustrated above. As previously mentioned, the intermediate section 30 may have varying thicknesses or dimensions along its length to provide different physical characteristics, or may be shaped or curved as shown to better accommodate the anatomical features of the patient. The lateral wall or bracket 36 may include an aperture 60 for receiving a fastener, such as a rivet. In addition, the spacer 500 may also include surface modifications such as barbs or teeth 40, 512 to facilitate tissue attachment, bonding or fixation. At least one back plate 410 may extend from the lower portion 32. The backboard 410 can be positioned within the sacral canal and against the sacrum when implanted.

A side sleeve or plate 502 may be provided that is attached to the spacer body 500. The side sleeve or plate 502 may include a middle portion 506, which may be similarly shaped and configured as the middle portion 30 of the spacer body 500, and a lower portion 508 and an upper portion 504. The lower portion 508 may include a recess (not shown) for receiving a tab 510 extending from the lower portion 32 of the spacer body 500. The lower portion 508 may also include notches 516 for locking the ratchet 514 provided on the tab 510. The legs 402 can extend from the lower portion 508 to hook over the middle crest of the sacrum 8. The upper portion 504 may include a wedge 518 that rests on an outer surface of the upper portion of the spacer body 500. Ramps 520 may be provided on spacer 500 to limit the extension of wedges 518 past stent 36.

In use, the spacer 500 may first be inserted by positioning the back plate 410 adjacent the sacrum and placing the spinous process 2 of the L5 vertebra between the lateral walls or the brackets 36. The side sleeve or plate 502 can then be placed against the spacer body 500 such that the wedge 518 extends under the spinous processes and the tongue 510 of the spacer body snaps into the groove of the side sleeve 502. The legs 402 of the side sleeve can hook over the middle crest of the sacrum 8 as shown in fig. 39.

Fig. 40A and 40B illustrate another exemplary embodiment, wherein the spacer body 550 may include a medial portion 30, an upper portion 34, and lateral walls or legs 36 similar to the spacer bodies described and illustrated above. As previously mentioned, the intermediate section 30 may have varying thicknesses or dimensions along its length to provide different physical characteristics, or may be shaped or curved as shown to better accommodate the anatomical features of the patient. The lateral wall or bracket 36 may include an aperture 60 for receiving a fastener, such as a rivet. In addition, the spacer 550 may also include surface modifications such as barbs or teeth 40, 512 to facilitate tissue attachment, bonding or fixation. As shown in fig. 40A, the middle portion 30 may extend to have a lower platform 580 with a dovetail projection 582 and a slot 584 thereon. The second part or bottom 554 may include an upper platform 570 having a recess 572 therein and a ratchet 574 located within the recess 572 to form a dovetail connection with the lower platform 580 when the first and second parts are assembled together as shown in FIG. 40B. A back plate 410 and standoffs 402 similar to those shown and described above can be provided on the second member 554.

In use, as shown in fig. 41, the second member 554 can be positioned over the sacrum 8 with the backboard 410 resting within the sacral canal and the legs extending around the middle crest of the sacrum 8. Next, the first member 552 is secured to the second member 554 by sliding the dovetail projection 582 into the recess 572 of the second member 554 and causing the slot 584 to catch the ratchet 574. The spinous process 2 of the L5 vertebra can be positioned within the lateral wall or the bracket 36.

It is envisioned that a surgeon may use the device of the present disclosure to treat a variety of clinical problems. For example, the device may be used to treat degenerative disc disease and/or disc herniation. The devices may also be used to treat spinal stenosis, including central and/or lateral canal stenosis. The devices may be used before, after, or in conjunction with other treatments or implants, including adjacent rigid fixation, adjacent spinal decompression, fusion, and/or facet replacement (facereplacement) or repair.

The devices of the present disclosure can be surgically implanted in a variety of ways without compromising the efficacy of the device. For example, the surgeon may select a number of different surgical methods and/or incision locations and/or sizes. In addition, the surgeon may implant the various components of the device in a different order. The particular surgical procedure may be selected based on patient-specific clinical factors.

The devices of the present disclosure may be implanted using a variety of different incisions and/or surgical procedures. For example, in one embodiment, the surgeon may use a midline incision over the lumbar and sacral vertebrae to expose the L5-S1 interspinous region. Alternatively, the surgeon may use one or more incisions located on the lateral sides of the spinal column. In addition, the surgeon may use minimally invasive means, including various scopes, cannulas, and/or robotic (smart) implant devices, to deliver the device to the surgical site.

After making the appropriate incision to expose the operative area, the components of the device can be implanted using a number of different steps that can be performed in different sequences. For example, the surgeon may first implant one or more anchors 18 to the sacrum, followed by implantation of the spacer body 12 into the interspinous space L5-S1. The spacer body 12 can then be secured to the fixation rod 16, and the fixation rod 16 can ultimately be secured to the sacrum 8.

In another technique, the surgeon may first implant the spacer body 12. The anchor 18 can then be secured to the sacrum and the fixation rod 16 can be secured to the anchor 18. The surgeon may accomplish this by securing the device 10 to the spinous processes of the vertebrae using one or more ligaments, sutures, and/or rigid fixation sleeves 220, 260, 280.

Furthermore, the device can be provided in a partially assembled form. In this embodiment, the spacer body 12 may be preassembled and securely fixed to the fixation rod 16. In this way, the spacing body 12 may have a predetermined degree of lateral movement or rotation relative to the attached fixation rod 16.

In another aspect of the disclosure, the device may be assembled from modular kits. The surgeon may separately select the size, shape, and/or physical characteristics of the various components, including the spacer body 12, fixation rod 16, anchor 18, flexible fixation element 180, and/or fixation sleeves 220, 260, 280. The surgeon may then assemble the components and select the appropriate degree of lateral movement and/or rotation for the spacer body 12 and fixation rod 16 as desired.

The anchor 18 can be secured to the sacrum in a variety of orientations. For example, in one embodiment, device 10 may include two polyaxial screws. A polyaxial screw can be inserted on the opposite side of the sacrum 8. A polyaxial screw may be inserted into the sacral ala or pedicle and oriented in an anterior-lateral direction. The surgeon may select different orientations and anchor arrangements depending on clinical factors such as surrounding bone disease and/or previous surgery or implantation.

It is contemplated that the device 10 of the present disclosure may provide improved systems and methods for treating various spinal disorders. For example, the device provides a mechanism for treating spinal disorders at the level/height of the L5-S1 spine (vertebral level). In addition, the devices of the present disclosure may also be used to treat spinal disorders at other spinal levels. However, the device of the present invention may also be used to stabilize the lumbar vertebrae above the level of L5. For example, for an L5 laminectomy, the device of the present invention may be used to stabilize the L4 vertebra while the screws of the rod-based device system are seated within the pedicle of the adjacent L5 vertebra, thereby providing a bearing bridge between the L4-L5 regions. It is therefore contemplated that the devices provided by the present disclosure, and in particular rod-based systems, may be used to stabilize any pair of adjacent vertebrae on a supported spinous process by securing the anchors of the rods to the pedicles of the adjacent vertebrae.

In addition, it is contemplated that the devices of the present invention may be used as interspinous spinal stabilization implants that are placed between two or more adjacent vertebrae. This may be accomplished by providing means having substantially similar features both above and below the central portion 30 of the spacer body 12. For example, a device may be provided having a bracket 36 extending from the upper portion 34 and the lower portion 32 similar to that shown in FIGS. 10A-14D. Similarly, it is contemplated that implants having flanges 206, slots 246 or ratchet teeth 64 on both the lower portion 32 and upper portion 34 as shown in fig. 18A, 19A and 20A can be provided for use with the fixation sleeves 220, 260, 280 on both ends of the device.

The methods and devices of the present disclosure are significantly less invasive and/or produce less pronounced and more reversible anatomical changes than other methods, including spinal fusion and total disc replacement. The devices of the present disclosure may limit normal spinal motion but provide some controlled motion in flexion, extension, rotation, and/or lateral bending. Furthermore, the devices and methods of the present disclosure may be particularly useful for treating degenerative disc disease and/or various stages of spinal stenosis, particularly at the level of L5-S1.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

Claims (23)

1. A lumbosacral interspinous stabilization device, comprising:

an inferior portion, a superior portion extending substantially parallel to the inferior portion, and a flexible U-shaped medial portion connecting the inferior portion to the superior portion, the inferior, superior, and medial portions collectively forming a substantially U-shaped spacer body configured to extend into an interspinous space and further comprising a pair of lateral walls extending from the superior portion for engaging a spinous process of a lumbar vertebra and a plurality of projections extending from the inferior portion, the plurality of projections comprising a pair of end plates configured to clamp a portion of a sacrum therebetween, each end plate including at least one threaded hole for receiving a bone screw configured to extend through the at least one threaded hole of one end plate, through bony tissue, and out of the at least one threaded hole of the other end plate.

2. The device of claim 1, wherein said lumbar vertebra is a fifth lumbar vertebra (L5).

3. The apparatus of claim 1, wherein the spacer has a flexibility that varies along its length.

4. The apparatus of claim 1, wherein the spacer has a thickness that varies along its length.

5. The apparatus of claim 1, wherein the spacer has a width that varies along its length.

6. The device of claim 1, wherein the lateral walls extend substantially parallel to each other prior to implantation.

7. The device of claim 1, wherein the lateral walls extend away from each other prior to implantation.

8. The device of claim 1, wherein the lateral walls are configured to be movable toward one another after implantation.

9. The device of claim 1, wherein the lateral wall is malleable.

10. The apparatus of claim 1, wherein each of the lateral walls comprises a through-hole.

11. The device of claim 10, further comprising a flexible fixation element configured to be tied around the through-hole and the spinous process.

12. The device of claim 11, wherein the flexible fixation element is a synthetic or natural material.

13. The apparatus of claim 12, wherein the artificial or natural material is selected from the group consisting of ligaments, tendons, fascia, muscles, suture material, fabric, mesh, and bands.

14. The device of claim 1, wherein the device comprises surface features for enhancing fixation to bone tissue.

15. The device of claim 14, wherein the surface features are selected from the group consisting of teeth, barbs, flanges, and surface roughening.

16. The device of claim 1, further comprising a bioactive material that promotes tissue growth after implantation.

17. The device of claim 16, wherein the bioactive material is contained within a coating on the device.

18. The device of claim 16, wherein the device is porous and the bioactive material is contained within the pores of the device.

19. The device of claim 1, wherein the device comprises a biocompatible metal or polymer.

20. The device of claim 19, wherein the biocompatible metal or polymer is selected from the group consisting of: titanium, titanium alloys, stainless steel, cobalt chrome alloys, ceramics, ultra high molecular weight polyethylene and polyetheretherketone.

21. The apparatus of claim 10, further comprising a fastener disposed between the through holes of the lateral walls.

22. The apparatus of claim 21, further comprising a cap disposed on a distal end of the fastener.

23. The apparatus of claim 21, further comprising a washer disposed on a distal end of the fastener.