Patent Application
20070088358
The present invention generally relates to devices and surgical methods for the treatment of various types of pathologies of the spine. More specifically, the present invention is directed to several different types of minimally invasive devices, methods, systems and kits for treating injured or diseased facet joints, intervertebral Joints and adjacent anatomy of the spine.
Back pain, particularly in the “small of the back” or lumbosacral (L4-S1) region, shown in
In many cases, the vertebral facet joints can be damaged by either traumatic injury or by various disease processes. These disease processes include osteoarthritis, ankylosing spondylolysis, and degenerative spondylolisthesis. Moreover, the facet joint has been implicated as a potential cause of neck pain for persons having whiplash. Aside from pain coming from the facets themselves, such damage to the facet joints can often result in eventual degeneration, abrasion, or wearing down of the facet joints, eventually resulting in pressure on nerves, also called “pinched” nerves, or nerve compression or impingement. The result is further pain, misaligned anatomy, and a corresponding loss of mobility. Pressure on nerves can also occur without an anatomic or functional manifestation of a disease, or pathology, at the facet joint, e.g., as a result of a herniated disc.
Many spinal pathologies mandating repair and/or replacement of an intervertebral disc (including many of those that may be currently treated through spinal fusion, interspinous distraction and/or dynamic stabilization), can often be traced back to degeneration, disease and/or failure of the facet joints. Alteration of the facet joint biomechanics resulting from an anatomic or functional manifestation of a disease can adversely affect the loading and biomechanics of the intervertebral disc, eventually resulting in degeneration, damage and/or failure of the intervertebral disc.
One type of conventional treatment of facet joint pathology is spinal stabilization, also known as intervertebral stabilization. Intervertebral stabilization desirably prevents relative motion between vertebrae of the spine. By preventing movement, pain can be reduced. Stabilization can be accomplished by various methods. One method of stabilization is spinal fusion. Another method of stabilization is fixation of any number of vertebrae to stabilize and prevent movement of the vertebrae. In addition, where compression or subsidence of the disc and/or facet joints has occurred, the physician can utilize fusion devices such as pedicle screw and rods systems, or interbody fusion cages, to elevate or “jack up” the compressed level, desirably obtaining a more normal anatomical spacing between the vertebral bodies.
Various devices are known for fixing the spine and/or sacral bone adjacent the vertebra, as well as attaching devices used for fixation, are known in the art including: U.S. Pat. Nos. 6,290,703, to Ganem, for Device for Fixing the Sacral Bone to Adjacent Vertebrae During Osteosynthesis of the Backbone; U.S. Pat. No. 6,547,790, to Harkey, III, et al., for Orthopaedic Rod/Plate Locking Mechanisms and Surgical Methods; U.S. Pat. No. 6,074,391, to Metz-Stavenhagen, et al., for Receiving Part for a Retaining Component of a Vertebral Column Implant; U.S. Pat. No. 5,569,247, to Morrison, for Enhanced Variable Angle Bone Bolt; U.S. Pat. No. 5,891,145, to Morrison, et al., for Multi-Axial Screw; U.S. Pat. No. 6,090,111, to Nichols, for Device for Securing Spinal Rods; U.S. Pat. No. 6,451,021, to Ralph, et al., for Polyaxial Pedicle Screw Having a Rotating Locking Element; U.S. Pat. No. 5,683,392, to Richelsoph, et al., for Multi-Planar Locking Mechanism for Bone Fixation; U.S. Pat. No. 5,863,293, to Richelsoph, for Spinal Implant Fixation Assembly; U.S. Pat. No. 5,964,760, to Richelsoph, for Spinal Implant Fixation Assembly; U.S. Pat. No. 6,010,503, to Richelsoph, et al., for Locking Mechanism; U.S. Pat. No. 6,019,759, to Rogozinski, for Multi-Directional Fasteners or Attachment Devices for Spinal Implant Elements; U.S. Pat. No. 6,540,749, to Schafer, et al., for Bone Screw; U.S. Pat. No. 6,077,262, to Schlapfer, for Posterior Spinal Implant; U.S. Pat. No. 6,248,105, to Schlapfer, et al., for Device for Connecting a Longitudinal Support with a Pedicle Screw; U.S. Pat. No. 6,524,315, to Selvitelli, et al., for Orthopaedic Rod/Plate Locking Mechanism; U.S. Pat. No. 5,797,911, to Sherman, et al., for Multi-Axial Bone Screw Assembly; U.S. Pat. No. 5,879,350, to Sherman, et al., for Multi-Axial Bone Screw Assembly; U.S. Pat. No. 5,885,285, to Simonson, For Spinal Implant Connection Assembly; U.S. Pat. No. 5,643,263, to Simonson for Spinal Implant Connection Assembly; U.S. Pat. No. 6,565,565, to Yuan, et al., for Device for Securing Spinal Rods; U.S. Pat. No. 5,725,527, to Biederman, et al., for Anchoring Member; U.S. Pat. No. 6,471,705, to Biederman, et al., for Bone Screw; U.S. Pat. No. 5,575,792, to Errico, et al., for Extending Hook and Polyaxial Coupling Element Device for Use with Top Loading Rod Fixation Devices; U.S. Pat. No. 5,688,274, to Errico, et al., for Spinal Implant Device having a Single Central Rod and Claw Hooks; U.S. Pat. No. 5,690,630, to Errico, et al., for Polyaxial Pedicle Screw; U.S. Pat. No. 6,022,350, to Ganem, for Bone Fixing Device, in Particular for Fixing to the Sacmum during Osteosynthesis of the Backbone; U.S. Pat. No. 4,805,602, to Puno, et al., for Transpedicular Screw and Rod System; U.S. Pat. No. 5,474,555, to Puno, et al., for Spinal Implant System; U.S. Pat. No. 4,611,581, to Steffee, for Apparatus for Straightening Spinal Columns; U.S. Pat. No. U.S. Pat. No. 5,129,900, to Asher, et al., for Spinal Column Retaining Method and Apparatus; U.S. Pat. No. 5,741,255, to Krag, et al., for Spinal Column Retaining Apparatus; U.S. Pat. No. 6,132,430, to Wagner, for Spinal Fixation System; U.S. Publication No. 2002/0120272, and to Yuan, et al., for Device for Securing Spinal Rods.
Another type of conventional spinal treatment is decompressive laminectomy. Where spinal stenosis (or other spinal pathology) results in a narrowing of the spinal canal and/or the intervertebral foramen (through which the spinal nerves exit the spine), and neural impingement, compression and/or pain results, the tissue(s) (hard and/or soft tissues) causing the narrowing may need to be resected and/or removed. A procedure which involves excision of part or all of the laminae and other tissues to relieve compression of nerves is called a decompressive laminectomy. See, for example, U.S. Pat. Nos. 5,019,081, to Watanabe, for Laminectomy Surgical Process; U.S. Pat. No. 5,000,165, to Watanabe, for Lumbar Spine Rod Fixation System; and U.S. Pat. No. 4,210,317, to Spann, et al., for Apparatus for Supporting and Positioning the Arm and Shoulder. Depending upon the extent of the decompression, the removal of support structures such as the facet joints and/or connective tissues (either because these tissues are connected to removed structures or are resected to access the surgical site) may result in instability of the spine, necessitating some form of supplemental support such as spinal fusion, discussed above.
While spinal fusion has become the “gold standard” for treating many spinal pathologies, including pathologies such as neurological involvement, intractable pain, instability of the spine and/or disc degeneration, it would be desirable to reduce and/or obviate the need for spinal fusion procedures by providing devices and systems that stabilize, or preserve motion of the spinal motion segment (including, but not limited to, facet joint repair or replacement, intervertebral disk replacement or nucleus replacement, implantation of interspinous spacers and/or dynamic stabilization devices, and/or facet injections).
The present invention includes the recognition that many spinal pathologies eventually requiring surgical intervention can be traced back, in their earlier stage(s), to some manner of a degeneration, disease and/or failure of the facet joints. Moreover, spinal fusion procedures can eventually require further surgical intervention. For example, degeneration of facet joints can result in an unnatural loading of an intervertebral disc, eventually resulting in damage to the disc, including annular bulges and/or tears. Similarly, degeneration and/or failure of a facet joint can potentially lead to slipping of the vertebral bodies relative to one another, potentially resulting in spondylolisthesis and/or compression of nerve fibers. In addition, degeneration of the facet joints themselves can become extremely painful, leading to additional interventional procedures such as facet injections, nerve blocks, facet removal, facet replacement, and/or spinal fusion. Thus, if the degenerating facet joint can be treated at an early stage, the need for additional, more intrusive procedures, may be obviated and damage that has already occurred to spinal structures such as the intervertebral disc of the treated level (as well as the disc and/or facets of other spinal levels) may be slowed, halted or even reversed.
Further, the invention includes the ability to accommodate anatomical variability to treat all vertebral levels, including L3-L4, L4-L5 and L5-S1, across a majority of the patient population.
The various embodiments disclosed and discussed herein may be utilized to restore and/or maintain varying levels of the quality or state of motion or mobility and/or motion preservation in the treated vertebral bodies. Depending upon the extent of facet joint degradation, and the chosen treatment regime(s), it may be possible to completely restore the quality or state of motion across the entire spinal motion segment, across one or more of the facet joints, or restore limited motion across the facet joint(s) to reduce or obviate the need for further treatment of the spinal motion segment.
A facet joint restoration device for use in a restoring a facet joint surface comprising: a cephalad facet joint element comprising (1) a flexible member adapted to engage a first vertebrae and (2) an artificial cephalad joint; and a caudad facet joint element comprising (1) a connector adapted for fixation to a second vertebrae and (2) an artificial caudad joint adapted to engage the cephalad facet joint. In some embodiments, the flexible member is adapted to engage a lamina of the first vertebrae. In other embodiments, the cephalad facet joint further comprises a plate with an anchoring mechanism adapted to engage a lamina of the first vertebrae. The anchoring mechanisms can be any suitable mechanism, including, for example, one or more anchoring mechanisms selected from the group consisting of teeth, ridges, nubs, serrations, granulations, a stem, a screw and spikes. In some embodiments, the cephalad facet joint element can be further adapted to comprises a second anchoring mechanism for securing the cephalad facet joint element to the first vertebrae. Further, the connector can be adapted to provide for fixation to a pedicle of the second vertebrae. In some embodiments it may be desirable for the second anchoring mechanism to further comprise a bony in-growth surface. As will be appreciated by those skilled in the art, in still other embodiments, the device can be configured to replace tissue removed from the facet joint, such as where the facet joint is resected. In still other embodiments, the device is adapted to restore or maintain motion or mobility for the facet joint. Further, a surface of one of the cephalad facet joint element or caudad facet joint element can be adapted to contour to an opposing mating surface. For example, the artificial caudad joint is a caudad cup having a concave surface. In some embodiments, the flexible member is a flexible cable. The flexible cable may be surrounded by a tube and/or may be further adapted to engage a lock. A spring washer adapted to engage a surface of the first or second vertebrae can be used in some embodiments, if desired. Further, it may be desirable to employ a malleable plate adapted to engage a laminar surface to support the cephalad facet joint element during implantation in other embodiments,
A facet joint replacement device for use in replacing all or a portion of a natural facet joint between a first vertebrae and a second vertebrae comprising: a first cephalad facet joint element having a fixation member adapted to engage a lamina or spinous process of the first vertebrae and a first caudad facet joint element, the first caudad facet joint element comprising a first caudad connector adapted to fixate to the second vertebral body and an artificial caudad facet surface adapted to engage with the cephalad facet joint element. In some embodiments, the fixation member is a flexible cable. A second cephalad facet joint element and a first crossbar can be adapted in some embodiments to connect the first cephalad facet joint element to the second cephalad facet joint element. In still other embodiments, a second caudad facet joint element and a first crossbar adapted to connect the first caudad facet joint element to the second caudad facet joint element. As will be appreciated by those skilled in the art, a second caudad facet joint element and a second crossbar adapted to connect the first caudad facet joint element to the second caudad facet joint element may be desirable in still other embodiments. The devices of the invention can further be adapted to include a laminar clamp. In some embodiments, it may be desirable for the laminar clamp to be adapted to engage the first cephalad facet joint element. In other embodiments, laminar clamp further comprises teeth for engaging a laminar surface. The laminar clamp can be further comprised of a first component and a second component adapted to adjustably engage the lamina. In some embodiments the first cephalad facet joint element is adapted to extend from the laminar clamp. Further, in other embodiments it may be desirable for the artificial caudad facet surface to be further adapted to comprise a caudad cup. In some instances, the first cephalad facet joint element can be adapted to rotatably engages the fixation member in some embodiments. In still other embodiments it may be desirable for the flexible cable to be surrounded by a tube. The facet replacement device of an embodiment can be further adapted to comprise a malleable plate adapted to engage a laminar surface to support the cephalad facet joint element.
A functional spine unit restoration system for use in a functional spine unit at a vertebal level in a spine comprising: a first and second cephalad facet joint element; a first and second caudad facet joint element comprising a connector adapted to secure a vertebral body and an artificial caudad joint adapted to engage the cephalad fact joint; a crossbar adapted to engage the first caudad facet joint element at a first end and the second caudad facet joint element at a second end; and an artificial intervertebral disc. In some embodiments of the invention, the anchor is a flexible cable. The cephalad facet joint can further comprise a plate with an anchoring mechanism adapted to engage the lamina. In still other embodiments the anchoring mechanism includes one or more anchoring mechanisms selected from the group consisting of teeth, ridges, nubs, serrations, granulations, a stem, and spikes. The plate can further be adapted to comprise a threaded rod adapted and configured to engage a threaded aperture of a bearing. The devices can also be configured from naturally occurring materials adapted to form the device, ceramic, metal, or polymer, or combinations thereof. In operation of the embodiments, the device restores the biomechanical operation of the functional spine unit. The device treats degenerating or diseased tissue in the target functional spine unit. In some embodiments, the device is adapted to restore or maintain motion or mobility for the target functional spine unit. In some instances a surface of one of the cephalad joint or caudad joint is adapted to contour to an opposing mating surface. In other instances, a surface of one of the cephalad joint or caudad joint is adapted to contour to an opposing mating surface. The flexible cable can be adapted in some embodiments to engage a lock. In still other embodiments, the system further comprises a laminar clamp. The laminar clamp can be adapted to engage the crossbar. Further, the laminar clamp can comprise teeth for engaging a laminar surface. In some embodiments, the laminar clamp is further comprised of a first component and a second component adapted to adjustably engage the lamina. The cephalad joints can be adapted to extend from the laminar clamp. Further, the laminar clamp can be adapted to engage the crossbar. In some embodiments, the orientation of a first cephalad joint to a first caudad joint is different than an orientation of a second cephalad joint to a second caudad joint. In still other embodiments, the laminar clamp is adjustable along a length parallel to a midline of the spine. As with other embodiments, the artificial caudad joint can be adapted to form a caudad cup. In still other embodiments, the artificial cephalad joint rotatably engages the flexible cable; the flexible cable can be surrounded by a tube. In some cases, a spring washer may be employed to engage a surface of a vertebral body. Further embodiments can be adapted to engage a malleable plate that engages a laminar surface to support the cephalad joint element during implantation.
A kit for restoring a functional spine unit at a vertebral level in a spine comprising: a first and second cephalad facet joint element; a first and second caudad facet joint element comprising a connector adapted to secure a vertebral body and an artificial caudad joint adapted to engage the cephalad fact joint; a crossbar adapted to engage the first caudad facet joint element at a first end and the second caudad facet joint element at a second end; and an artificial intervertebral disc.
All publications and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.
The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which:
FIGS. 6B-C illustrate the two components illustrated in
FIGS. 7A-C illustrate an implanted facet replacement device according to the invention from a posterior and lateral perspective;
FIGS. 8A-D illustrate an implanted facet replacement device according to another embodiment of the invention from a posterior and lateral perspective;
FIGS. 9A-B illustrate a facet replacement device according to another embodiment of the invention from a side view and a top view;
FIGS. 10A-C illustrate the facet replacement device of FIGS. 9A-B implanted from a posterior and lateral view;
FIGS. 12A-B illustrate a bilateral facet replacement system with a cross-bar according to another embodiment of the invention;
FIGS. 12C-D illustrates the facet replacement system implanted from different perspectives;
FIGS. 13A-B illustrate a facet replacement system having caudad cups, a cross-bar and a laminar clamp;
FIGS. 13C-D illustrate the clamp portion of the system implanted;
FIGS. 14B-D illustrate the facet replacement system of
FIGS. 15A-E illustrates a facet replacement system according to an alternate embodiment implanted from various perspectives;
FIGS. 16B-C illustrate the facet replacement system of
FIGS. 17A-C illustrate a facet replacement system according to an alternate embodiment, and the system implanted from various perspectives;
FIGS. 18B-C illustrate the facet replacement system of
FIGS. 19B-C illustrate the facet replacement system of
FIGS. 20B-D illustrate the facet replacement system of
FIGS. 21B-D illustrate the facet replacement system of
FIGS. 22B-D illustrate the facet replacement system of
FIGS. 27A-H illustrate the components of a translaminar facet arthroplasty cephalad construct system;
FIGS. 28A-B illustrate the translaminar facet arthroplasty cephalad construct system showing its construction and operation;
FIGS. 29A-C illustrate the translaminar facet arthroplasty cephalad construct system according to an alternate embodiment showing its construction and operation;
FIGS. 30A-c illustrate the translaminar facet arthroplasty cephalad construct system according to an alternate embodiment showing its construction;
FIGS. 31A-B illustrate a plate suitable for use with the fixation bearing systems described herein;
FIGS. 32A-C illustrate cross-sections of an alternate cephalad bearing fixation system;
FIGS. 33A-F illustrate various views of a fixation device suitable for use at a sacral level;
FIGS. 34A-B illustrates a translaminar fixation system incorporating the use of a spring washer;
FIGS. 35A-B illustrates a disc replacement device with a facet replacement component; and
FIGS. 36A-B illustrates a disc replacement device according to an alternative embodiment with a facet replacement component.
The invention relates generally to implantable devices, apparatus or mechanisms that are suitable for implantation within a human body to restore, augment, and/or replace hard tissue, soft tissue and/or connective tissue, including bone and cartilage, and systems for treating the anatomic or functional manifestation of injury or diseases, such as spinal pathologies. In some instances, the implantable devices can include devices designed to replace missing, removed, or resected body parts or structure. The implantable devices, apparatus or mechanisms are configured such that the devices can be formed from parts, elements or components which alone or in combination comprise the device. The implantable devices can also be configured such that one or more elements or components are formed integrally to achieve a desired physiological, operational or functional result such that the components complete the device. Functional results can include the surgical restoration and functional power of a joint, controlling, limiting or altering the functional power of a joint, and/or eliminating the functional power of a joint by preventing joint motion. Portions of the device can be configured to replace or augment existing anatomy and/or implanted devices, and/or be used in combination with resection or removal of existing anatomical structure.
The devices of the invention are designed to interact with the human spinal column 10, as shown in
An example of one vertebra is illustrated in
At the posterior end of each pedicle 16, the vertebral arch 18 flares out into broad plates of bone known as the laminae 20. The laminae 20 fuse with each other to form a spinous process 22. The spinous process 22 provides for muscle and ligamentous attachment. A smooth transition from the pedicles 16 to the laminae 20 is interrupted by the formation of a series of processes.
Two transverse processes 24, 24′ thrust out laterally, one on each side, from the junction of the pedicle 16 with the lamina 20. The transverse processes 24, 24′ serve as levers for the attachment of muscles to the vertebrae 12. Four articular processes, two superior 26, 26′ and two inferior 28, 28′, also rise from the junctions of the pedicles 16 and the laminae 20. The superior articular processes 26, 26′ are sharp oval plates of bone rising upward on each side of the vertebrae, while the inferior processes 28, 28′ are oval plates of bone that jut downward on each side. See also
The superior and inferior articular processes 26 and 28 each have a natural bony structure known as a facet. The superior articular facet 30 faces medially upward, while the inferior articular facet 31 (see FIGS. 2B-E) faces laterally downward. When adjacent vertebrae 12 are aligned, the facets 30 and 31, capped with a smooth articular cartilage and encapsulated by ligaments, interlock to form a facet joint 32. The facet joints are apophyseal joints that have a loose capsule and a synovial lining.
As discussed above, the facet joint 32 is composed of a superior facet and an inferior facet. The superior facet is formed by the vertebral level below the joint 32, and the inferior facet is formed in the vertebral level above the joint 32. For example, in the L4-L5 facet joint shown in
An intervertebral disc 34 between each adjacent vertebra 12 (with stacked vertebral bodies shown as 14, 15 in
Thus, the overall spine comprises a series of functional spinal units that are a motion segment consisting of two adjacent vertebral bodies (e.g., 14, 15 of
As previously described, a natural facet joint, such as facet joint 32 (FIGS. 2B-D), has a superior facet 30 and an inferior facet 31 (shown in
As will be appreciated by those skilled in the art, it can be difficult for a surgeon to determine the precise size and/or shape necessary for an implantable device until the surgical site has actually been prepared for receiving the device. In such case, the surgeon typically would desire to quickly deploy a family of devices and/or device components possessing differing sizes and/or shapes during the surgery. Thus, embodiments of the spinal devices of the present invention include modular designs that are either or both configurable and adaptable. Additionally, the various embodiments disclosed herein may also be formed into a “kit” or system of modular components that can be assembled in situ to create a patient specific solution. As will be appreciated by those of skill in the art, as imaging technology improves, and mechanisms for interpreting the images (e.g., software tools) improve, patient specific designs employing these concepts may be configured or manufactured prior to the surgery. Thus, it is within the scope of the invention to provide for patient specific devices with integrally formed components that are pre-configured.
The devices of the present invention are configurable such that the resulting implantable device is selected and positioned to conform to a specific anatomy or desired surgical outcome. The adaptable aspects of embodiments of the present invention provide the surgeon with customization options during the implantation or revision procedure. It is the adaptability of the present devices and systems that also provides adjustment of the components during the implantation procedure to ensure optimal conformity to the desired anatomical orientation or surgical outcome. An adaptable modular device of the present invention allows for the adjustment of various component-to-component relationships. One example of a component-to-component relationship is the rotational angular relationship between an anchoring device and the device to be anchored. Other examples of the adaptability of modular device of the present invention are as described in greater detail below. Configurability may be thought of as the selection of a particular size of component that together with other component size selections results in a “custom fit” implantable device. Adaptability then can refer to the implantation and adjustment of the individual components within a range of positions in such a way as to fine tune the “custom fit” devices for an individual patient. The net result is that embodiments of the modular, configurable, adaptable spinal device and systems of the present invention allow the surgeon to alter the size, orientation, and relationship between the various components of the device to fit the particular needs of a patient during the actual surgical procedure.
To prepare the anatomy for implantation of the devices and systems disclosed herein, it may be desirable to alter or remove anatomy from the patient. For example, common ligaments, such as capsular ligaments, anterior longitudinal ligaments, interspinous ligaments and/or ligamentum flavum may be altered or removed, as well as portions of the cephalad and/or caudad vertebra, including inferior/superior facets, or portions thereof. Alternatively, less-invasive and/or minimally-invasive surgical tools and techniques are provided that, among other things, limit the need for resection and/or alteration of such anatomy, which desirably allows for greater retention of natural anatomical features that can (1) stabilize the spine, thereby desirably reducing loads experienced by the facet replacement device, and/or (2) load-share with the facet joint replacement device in bearing physiological loads.
In order to understand the configurability, adaptability and operational aspects of the invention, it is helpful to understand the anatomical references of the body 50 with respect to which the position and operation of the devices, and components thereof, are described. There are three anatomical planes generally used in anatomy to describe the human body and structure within the human body: the axial plane 52, the sagittal plane 54 and the coronal plane 56 (see
Turning back to
The facet joint 32, is formed from a superior articular facet 30 and an inferior articular facet 31. The inferior articular facet 31 has a cephalad facet surface and the superior articular facet 30 has a caudad facet surface. When healthy and normal, each of these surfaces has an articulating cartilage layer positioned adjacent the facet surfaces to improve the movement of the facet joint 32 in operation. In addition to the caudad facet surface and the cephalad facet surface that comprise the opposing joint surfaces, each of the superior articular facet 30 and the inferior articular facet 31 may have additional surfaces on the sides of the facets. A facet capsule 86 is also provided that surrounds the facet joint 32 and to communicate with the various surfaces on the sides of the superior articular facet 30 and the inferior articular facet 31. Where the anatomic or functional manifestations of a disease has resulted in a spinal pathology, facet joint degradation can occur, which includes wear of the articulating surface of the facet joint. Normally, the peripheral, cortical rim of the joint is not affected, or is minimally affected. With hypertrophic facets, the mass of cortical bone and action of the osteophytes can make the facet larger than normal as the facet degenerates. When a facet begins to wear, the biomechanics of the functional spine unit are altered, which can cause further damage to the facet joint as well as pain. Moreover, such alteration of the biomechanics can compromise the integrity of the remainder of the functional spinal unit, and lead to intervertebral disc degradation and damage, further facet joint degradation and damage, spondylolithesis and/or reductions/changes in disc height, as well as the potential occurrence of spinal stenosis (all of which could occur not only in the affected spinal level, but in other spinal levels as well).
The relative locations and/or orientations for the fixation elements 412 and 422 of the artificial facet joint 410 are generally mandated by the patient's natural anatomy (such as the locations, orientations and/or conditions of the pedicles, lamina, spinous process and/or vertebral bodies themselves), as well as the objectives of the surgical procedure, and the tissues and structures removed and/or modified during the surgical procedure. Desirably, these fixation elements will be optimally placed for secure fixation. However, optimal placement for secure fixation may not always equate to optimal placement for proper function of the various components of the facet replacement device, and thus there may be a need to adjust and/or alter the position(s) and/or orientation(s) of the artificial cephalad and caudad joints 426 and 428 relative to their respective fixation elements (which desirably can be accommodated by the previously-described adjustability of the caudad and cephalad components). Accordingly, after implantation and adjustment, the artificial caudad joint 428 and the artificial cephalad joint 426 may be in an anatomically correct position within the patient's body (relative to the anatomical structures they augment and/or replace) or in an non-anatomically correct position, depending on the desired clinical outcome and the condition of the spinal anatomy (including, e.g., whether the vertebra have been anatomically altered, either surgically or naturally), as well as any other considerations and requirements of the situation.
In one alternate embodiment, the fixation element could comprise a cable 3230 and cannulated tube 3235 (see
The device 410 can be attached to a cut or resected portion of the vertebra. The cephalad portion of the device 410 is secured to the vertebral via an extension cable 422 that passes through the lamina (see, 20 of
A portion of the vertebra may be surgically removed or altered, for example, to permit access to and removal of the superior facet of the caudad vertebra. A pedicle anchor 412 is then deployed and the caudad bearing is affixed to the anchor. Adjustability of the implanted device 410 may be achieved through the use of varying sized components as well as altering configuration and fit (e.g., with the use of polyaxial anchors, tapers, interlocking splines, etc.). Implantation of the device can also be accomplished using minimally invasive surgical techniques. Repair, replacement and/or augmentation can also be performed using limited-open, modified-open, and/or fully open surgical procedures. For example, where facet joint replacement is necessary, but removal of soft and/or hard tissue in and/or adjacent the spinal canal is not warranted or desired (such as where spinal stenosis and nerve impingement is not a significant concern), the repair and/or replacement of one or more facet joints can be accomplished in a least-invasive fashion using one or more cannulae to implant the device and associated hardware. Alternatively, where the removal of the facet joint 32 and/or lamina 20 is necessitated (shown in
Another advantage of the embodiment is that the device is positioned within the lamina with only limited portions of the implant extending outwards from the vertebral body. This arrangement presents a low-profile to the surrounding soft tissue structure, resulting in less interaction between the device and the surrounding soft tissues, as well as less displacement of natural tissues due to the presence of the implant. Moreover, anchoring the cephalad portion of the device within the lamina and/or spinous process reduces and/or eliminates the opportunity for unwanted contact between the dura and the implanted device. Desirably, once the facet replacement components are implanted, the device will induce a healing response in the patient's body, causing formation of a capsule or pseudo-capsule of soft tissue (including scar tissue) around the articulating elements of the facet replacement prosthesis.
Further, based on the position of the caudad bearing surface, a translaminar aperture or hole can be placed through a percutaneous cephalad approach targeting the bearing surface. Through a caudad approach (which may be similarly minimally-invasive, limited open, open or through an expanding cannula), the cephalad bearing portion of the device is placed in a desired position/orientation and the tension cable 422 is drawn in a retrograde fashion through the translaminar opening formed in the lamina or spinous process. The cable is then tightened and secured to the superior aspect of the lamina 20. Once the cable 422 is secured and the superior aspect of the lamina, the cephalad portion of the device is secured against the cut surface of the inferior facet. Using such a minimally invasive surgical approach, the posterior structures, except for the facet and facet capsules, can be left undisturbed.
As will be appreciated upon reviewing the entire specification, the device 410 will also work in conjunction with a total disc replacement. Use with a total disc replacement provides a solution for the total disc replacement contraindication of facet degeneration. Implantation of a total disc replacement device prior to implanting the facet restoration device 410 opens the disc space, aiding in any decompression of the joint that may be necessary. The device may be used unilaterally or bilaterally, depending on the nature of and stage of disease, and can be used at multiple levels of the spine. Similarly, removal of some or all of the facet structures (and lamina, etc.) of the targeted vertebral level may permit the passage of one or more components of the artificial disc replacement (or nucleus replacement, or annular repair material, and their respective tools) through the removed facet tissues via a lateral, posterior-lateral and/or posterior approach. The functions of the removed tissues can then be replaced by implanting the facet replacement prosthesis as described herein.
The relative positions of facet joint 510, 510′ and fixation element 512, 512′ may be set prior to implant, after implant, OT both before and after implant. After implant and adjustment, the artificial caudad joint 528, 528′ and the artificial cephalad joint 526, 526′ may be in an anatomically correct position within the patient's body or in an non-anatomically correct position, depending on the desired clinical outcome and/or the condition of the spinal anatomy (e.g., whether the vertebra have been anatomically altered, either surgically or naturally), as well as any other considerations and requirements of the situation. In this embodiment, the cephalad component of the device is secured to the lamina (shown in FIGS. 2A-D, 20) of the cephalad vertebral body (e.g., 14 of
One or more prongs or projections 518, 519 are positioned on the inner surface of the base 517 of the cephalad facet joint component to prevent rotation and/or secure the component to the lamina. For example, the projections 518 are positioned such that they penetrate the laminar surface while the flattened projections 519 are positioned to desirably lay adjacent or against the outer surface of the lamina. As will be appreciated by those skilled in the art, the laminar surface can be prepared prior to the implanting the device, e.g., through resection of the articulating facet surface and/or the laminar surface, to provide a surface which, when abutting against the cephalad component will properly orient and position the cephalad component relative to an adjoining caudad bearing component. The cephalad facet joint component 526 has a bearing surface 527 that engages a bearing surface 529 of a caudad facet joint component 528.
The components can be secured into and through the pedicles of the vertebral body. A multi-axial or poly-axial anchor can be used to permit in situ adjustment of the caudad bearing surface. Alternatively, an adjustable component can be used that permits adjustment. As will be appreciated by those skilled in the art, other anchors can be employed without departing from the scope of the invention.
FIGS. 7A-C depict an alternative embodiment of a facet replacement device, similar to those depicted in
The caudad component 728 can also be secured into and through the pedicles of the caudad vertebral body. As illustrated in this embodiment, the caudad component is secured to the vertebral body by use of a fixation element 712.
FIGS. 8A-D illustrate an implanted facet replacement device according to another embodiment of the invention. The device 810 as implanted is configured to replace a portion of a natural facet joint. The fixation element enables the device 810 to connect to a facet joint via, for example, a polyaxial connection 814. The connection 814 permits the artificial caudad joint 828 and caudad base 816 to be adjusted with respect to the fixation element 812 around more than one axis within the patient. As can be appreciated by reviewing
FIGS. 9A-B illustrate a facet replacement device according to another embodiment of the invention from a side view and a top view. The device 910 can be implanted to replace a portion of a natural facet joint. The fixation element 912 enables the device 910 to connect to a facet joint via, for example, an adjustable (e.g., polyaxial) connection 914. The connection 914 permits artificial caudad joint 928 and caudad base 916 to be rotated with respect to the fixation element 912 around more than one axis within the patient, if desired. As can be appreciated by reviewing
As with previous embodiments, during a surgical implantation, the cephalad facet surface of the vertebral body can be prepared prior to implantation of the device. Thereafter, the proximal end of the cable or rod (which may be flexible or non-flexible) is inserted into and through the lamina and/or spinous process in a desired direction and orientation with a first end of the anchoring stem 922 attached to the artificial cephalad joint component 926 and the second end adapted to engage an anchor 924 or cable lock. The anchor, or other securing device, can be attached (e.g., threaded) onto the end of the anchoring device 922 and abutted against the bony surface or lamina 20 of the vertebral body 14. A tensioning tool and/or crimper, or similar device, can be used to provide sufficient torque to lock the anchor 924 onto the anchoring stem 922 (if desired), thereby drawing the projections of the base 916 toward the laminar surface. As discussed above, as the base is drawn toward the laminar surface, the projections may be drawn into and/or against the lamina, depending upon the actual configuration of the projections. Thereafter, once a desired tension has been reached, the device can then be secured by locking the anchoring stem 922 with the anchoring device 924. Desirably, this arrangement will allow much of the loading experienced by the artificial cephalad joint component 926 to be compressive in nature, thereby allowing transfer of a significant amount of these forces directly into the laminar surface, rather than to the cable or rod 922. As described above with respect to
FIGS. 10A-C illustrate the facet replacement device of FIGS. 9A-B implanted from a posterior and lateral perspective. In this embodiment, the caudad attachment is notched on the facet surface. The notching enables the device to engage a prepared or resected surface when implanted.
Turning now to,
As discussed above, the construction can be adapted and configured to permit continuous adjustment through relative rotation of the facet joint element and the fixation element around many different axes through an adjustability range. In other embodiments, however, the number of axes of rotation may be limited, and the movement may be permitted only in discrete increments. In various embodiments the facet joint element may be moved medially, laterally, superiorly and/or inferiorly with respect to the fixation element. The facet joint elements 1120, 1120′ are further comprised of an anchoring stem 1122, 1122′, which is securable through, for example, the lamina and/or spinous process. The anchoring stems 1122, 1122′ are adapted to engage an artificial cephalad joint 1126, 1126′ having a surface adapted to mate with an opposing surface of the artificial caudad joint 1128, 1128′. The artificial caudad joint is configured to present a surface that received the artificial cephalad joint. Thus, for example, forming mating convex/concave bearing surfaces enables the movement of each of the respective cephalad and caudad components 1126, 1128 of the facet joint element 1120 to occur more smoothly. The artificial caudad joint is further adapted to engage the base 1116, 1116′ of the fixation element 1112, 112′ such that the artificial caudad joint can adjusted during implantation and then locked in place using a base anchor.
The relative positions of each of the facet joints 1110, 1110′ and fixation elements 1112, 1112′ may be set prior to implant, after implant, or both before and after implant. After implant and adjustment, the artificial caudad joint 1128, 1128′ and the artificial cephalad joint 1126, 1126′ may be in an anatomically correct position within the patient's body or in an non-anatomically correct position, depending on the desired clinical outcome and/or the condition of the spinal anatomy (e.g., whether the vertebra have been anatomically altered, either surgically or naturally), as well as any other considerations and requirements of the situation. In this embodiment, the cephalad component of the device is secured to the lamina (shown in FIGS. 2A-D, 20) of the cephalad vertebral body (e.g., 14 of
The facet replacement components can be further adapted to incorporate artificial ligaments between the articulating arms and/or the treated vertebral bodies. Alternatively, the devices could incorporate a flexible capsule around some or all of the facet/articulating joint surfaces. As will be appreciated by those skilled in the art will appreciate, multiple attachment points can be included, e.g., with the use of apertures, holes, hooks, etc. For attaching existing ligaments, tendons and/or other soft or hard tissues at the conclusions of the surgical procedure to promote healing and further stabilization of the affected level. Moreover, the natural healing response of the body may create a pseudo-capsule of soft and/or scar tissue abound the cephalad and caudad articulating surfaces of the facet replacement device, which may in some manner serve to duplicate some of the functions of the natural facet capsule.
FIGS. 12A-B, a bilateral facet replacement system with a cross-bar is depicted. Similar to the embodiment shown in
Similar to other embodiments, the connector 1214, 1214′ permits the artificial caudad joint 1228, 1228′ and caudad base 1216, 1216′ to be moved and/or rotated with respect to the fixation element 1212, 1212′. The facet joint elements 1220, 1220′ further incorporate anchoring stems 1222, 1222′, which are securable through, for example, the lamina and/or spinous process. The anchoring stems 1222, 1222′ are adapted to engage a artificial cephalad joint 1226, 1226′ having a surface 1227, 1227′ adapted to mate with an opposing surface of the artificial caudad joint 1228, 1228′. The artificial caudad joint is configured to present a surface 1229, 1229 that received the artificial cephalad joint.
As with other embodiments, the relative positions of each of the facet joints 1210, 1210′ and fixation elements 1212, 1212′ may be set prior to implant, after implant, or both before and after implant. After implant and adjustment, the artificial caudad joint 1228, 1228′ and the artificial cephalad joint 1226, 1226′ may be in an anatomically correct position within the patient's body or in an non-anatomically correct position, depending on the desired clinical outcome and/or the condition of the spinal anatomy, as well as any other considerations and requirements of the situation. FIGS. 12C-D illustrates the facet replacement system implanted from the posterior and lateral perspectives.
The crossbar 1330 has a first end 1331 and a second end 1331′. In the illustrated embodiment the crossbar 1330 is a three piece bar where the ends 1331, 1331′ form a threaded male portion. Attached to each crossbar end 1331, 1331′ is an internally threaded ball 1336, 1336′ sized to receive the threads of the cross bar 1330. The threaded ends allow for the width of the crossbar to be adjusted to mate with the width between caudad anchors 1332, 1332′. Additional alternative embodiments of the crossbar 1330 could include a series of solid crossbars of varying widths and/or thicknesses, or an adjustable crossbar having some form of locking or biasing mechanism (such as a spring-loaded tensioner or detent mechanism, etc.).
The crossbar mounts 1334, 1334′ are a connection structure to couple the laminar clamp 1340 to the crossbar 1330. The laminar clamp has ends that extend through a channel in the crossbar mounts 1334, 1334′. In the illustrated embodiment, the crossbar mount 1334, 1334′ includes a laminar anchor engaging portion, a crossbar engaging portion and a fixation element 1338, 1338′. The fixation element 1338, 1338′ anchors the laminar anchor ends with the channel of the crossbar mounts 1334, 1334′. Fixation element can be a screw, stem, cork-screw, wire, staple, adhesive, bone, and other material suitably adapted for the design. As will be described in greater detail below, embodiments of the crossbar mount 1330 provides adaptability.
In the embodiment shown in
FIGS. 13C-D illustrate the clamp portion of the system implanted within a spine from a posterior view of the spine (
FIGS. 15A-C illustrate a facet replacement system 1500 constructed according to an alternate embodiment, from various perspectives. This embodiment of the facet replacement system is particularly well suited to anatomical locations where trans-laminar attachment may not be an optimal solution, as well as to locations where poor laminar bone quality and/or anatomical limitations preclude the use of translaminar anchors. For example, at the L5-S1 vertebral level, where approximately 50% of current intervertebral disc replacement operations occur, the L5 lamina is generally thinner and weaker than that of other vertebral levels. Stresses on the facet joint at this level are also generally the highest of the spine and the angle of the facet joint is essentially normal to the axis of the lamina. The caudad cups 1533, 1533′ are configured to rest against the sacrum. As illustrated in
FIGS. 17A-c illustrate a facet replacement system 1700 according to yet another alternate embodiment, as well as the system 1700 implanted from various perspectives. The system has a laminar clamp 1740 formed from two opposing modular clamp assemblies. In lieu of a cross-bar (see 1630 of
As illustrated, on one side, the bearing surface has a cross-bar 1750, 1750′ that extends from the bearing surface 1746 to engage the externally positioned U-shaped clamp 1747′. As depicted herein, the surface of the clamp nearest the caudad cup 1733′ is adapted, e.g. forming a socket 1752, to receive a rounded ball end of the cross-bar. On the other side of the device, one or more joints 1152′ are provided into which the cross-bars 1753, 1753′ can be locked using a locking mechanism 1754, 1754′, 1754″. Providing more than one cross-bar on either side of the laminar clamp 1740 with poly-axial connectors enables the device to achieve a greater degree of flexibility.
FIGS. 17B-c illustrate the facet replacement system of
FIGS. 18B-c illustrate the facet replacement system of
Turning now to,
The facet replacement device of
FIGS. 24A-C are various views of the facet replacement system of
FIGS. 27A-H illustrate the components of a translaminar facet arthroplasty cephalad construct system, such as described in FIGS. 25A-D.
FIGS. 28A-B illustrates components of the translaminar facet arthroplasty cephalad construct system shown in
FIGS. 29A-C illustrates a facet arthroplasty system cephalad construct according to an alternate embodiment employing the components of
FIGS. 30A-C illustrate a facet arthroplasty cephalad construct system according to an alternate embodiment. The system includes a circular flange housing into which a set screw is placed to anchor the system together. The set screw locks the cephalad arm and the outside lock locks the crossbar.
FIGS. 31A-B illustrate another component of a construct system suitable for use with a disc-facet arthroplasty system. A malleable or pre-formed plate 3100 is provided that is adapted to secure a cephalad bearing to the bone. The cap structure 3101 fits on one side of a lamina, and can form a cephalad bearing surface, if desired. A rod can be inserted through the cap on one side of the lamina and through an aperture 3103 in the arm on the other side of the lamina (the rod can comprise a trans-laminar cephalad fixation mechanism as previously-described). The arm 3102 secures the cephalad bearing to the lamina, which may be augmented using laminar screws through one or more of the remaining apertures in the plate. This system may be particularly well suited for use in conjunction with the various trans-laminar cephalad anchoring systems, such as the various systems described in
FIGS. 33A-F illustrate various views of a fixation device suitable for use at a sacral connection for a caudad cup 3333. As would be appreciated by those skilled in the art, the sacrum may not be of the strongest bone quality and/or any spinal implant in the sacrum will likely experience the highest compressive and bending loads in the spine. Accordingly, securing mechanical devices to the sacrum presents an additional challenge. Once mechanism for overcoming this challenge is to provide a dual fixation caudad cup design 3300, such as that depicted in
FIGS. 34A-B illustrate a cephalad translaminar fixation system incorporating the use of a spring washer 3400. The spring washer is configured in a petal design to allow the washer edges to conform to the irregular bone surface. The springiness of the washer desirably creates tension which better secures the device to the bone. The washer can be used at any location where a device is adapted to engage bone and is suitable for use with any of the embodiments disclosed herein. The washer may also incorporate a textured or bony in-growth surface to facilitate bony fixation.
FIGS. 35A-B illustrate a disc replacement device 3500 in combination with a facet replacement component. The device is adapted to attach to a portion of the facet replacement device. In turn, the facet replacement device engages a portion of each of the vertebral bodies (although, in alternative embodiments, the facet replacement device may be solely anchored to the disc replacement device, and the disc replacement device may or may not be anchored to the surrounding vertebral bodies). The disc component of the device can be any artificial device capable of at least partially restoring the natural motion of the intervertebral disc. The disc can be an articulating disc, a cushion disk and a spring-based disc. Various disc replacement devices are described in U.S. Pat. No. 5,071,437 to Stefee et al. for Artificial Disc; U.S. Pat. No. 6,113,637 to Gill et al. for Artificial Intervertebral Joint Permitting Translation and Rotational Motion; U.S. Pat. No. 6,001,130 to Bryan et al. for Human Spinal Disc Prosthesis with Hinges; U.S. Pat. No. 4,759,769 to Hedman et al. for Artificial Spinal Disc; U.S. Pat. No. 5,527,312 to Ray et al. for Facet Screw Anchor; U.S. Pat. No. 5,824,094 to Ray et al. for Spinal Disc; U.S. Pat. No. 5,401,269 to Buttner-Janz for Intervertebral Disc Endoprosthesis; 5,824,094 to Serhan et al. for Spinal Disc; 5,556,431 to Buttner-Janz for Intervertebral Disc Endoprosthesis; U.S. Pat. No. 5,674,296 to Bryan et al. for Human Spinal Disc Prosthesis; and U.S. Patent Pub US2005/0055096 A1 to Serhan et al. for Functional Spinal Unit Prosthetic. The articulating motion disc can have a three piece design 3510, 3512, 3514 with two endplates 3510, 3514 and a core 3512. Each of the plates can be provided with one concave surface adapted to receive a convex surface presented by the core; thus forming a ball-and-socket joint.
FIGS. 36A-B illustrates a disc replacement device 3600 according to an alternative embodiment with a facet replacement component and artificial linkages 3610 between the vertebral bodies. In this embodiment, the disc replacement device engages both a portion of the facet replacement device as well as a portion of the vertebral body. Moreover, this embodiment includes a trans-vertebral link between the components of the facet replacement device that can be created from a variety of materials including, for example, titanium, stainless steel, or radiolucent polymer materials such as polyether ether ketone (PEEK™) provided by Victrex PLC (United Kingdom). The trans-vertebral link may or may not be rigid See, for example, U.S. Patent Pub. US2005/0033434 A1 to Berry for Posterior Elements Motion Restoring Device. Attachment between the facet prosthesis and disc not only reduces or obviates the opportunity for migration of the artificial disc replacement, it also reinforces and/or augments the anchoring of the facet replacement component to the vertebral body, as well as preventing subsidence of the artificial disc replacement into the respective upper or lower endplate of the treated vertebral bodies, Moreover, such attachment allows the attachment mechanism to be utilized in a minimally invasive fashion to reposition the artificial disc replacement within the disc space (anterior/posterior and/or laterally, or a combination thereof),
In addition, attachment between facet prosthesis and disc can alter the loading on the artificial disc replacement, if desired. For example, where the artificial disc is failing in some mode of operation (such as during anterior loading of the disc), repositioning of the disc replacement in a more anterior location may alter loading of the disc to a more posterior direction, thereby extending the life of the disc replacement before removal, replacement and/or repair (and subsequent surgical intervention) is required. In a similar manner, utilizing non-symmetrical connections between the anterior and poster vertebral bodies, can allow you to preferentially load the disc replacement prosthesis in a non-symmetrical manner, or account for anatomical deformities that preclude or prevent the insertion of a symmetrical (i.e. -standard) spinal joint replacement device.
The invention includes systems that include a single functional spinal unit joint replacement system. The devices, systems and methods provided herein reduce and/or eliminate replacement, repair and/or displacement of the artificial disc replacement device relative to the vertebral bodies during the life of the implantation. By linking disc replacement to the facet replacement, the added benefit of reducing or redistributing the loading of the spinal anchors (pedicle, lamina, spinous process and/or a combination thereof) can be achieved.
In some embodiments it may be desirable to incorporate artificial ligaments between the articulating arms and/or the treated vertebral bodies. Additionally, in some embodiments it could be desireable to incorporate a flexible capsule around some or all of the facet/articulating joint or its surfaces. Alternatively, the facet replacement device can be adapted to incorporate multiple attachment points (apertures, holes, hooks, etc.) for attachment of existing ligaments, tendons and/or other soft or hard tissues at the conclusion of the surgical procedure to promote healing and further stabilization of the affected levels.
The devices and components disclosed herein can be formed of a variety of materials, as would be known in the art. For example, where the devices have bearing surfaces (i.e. surfaces that contact another surface), the surfaces may be formed from biocompatible metals such as cobalt chromium steel, surgical steel, titanium, titanium alloys (such as Nitinol), tantalum, tantalum alloys, aluminum, etc. Suitable ceramics, including pyrolytic carbon, and other suitable biocompatible materials known in the art can also be used. Suitable polymers include polyesters, aromatic esters such as polyalkylene terephthalates, polyamides, polyalkenes, poly(vinyl) fluoride, PTFE, polyarylethyl ketone, and other materials that would be known to those of skill in the art. Various alternative embodiments of the spinal devices and/or components could comprise a flexible polymer section (such as a biocompatible polymer) that is rigidly or semi rigidly fixed such that the polymer flexes or articulates to allow the vertebral bodies to articulate relative to one another.
Various embodiments of the present invention relate to a total spine joint replacement system comprising a modular facet joint replacement in combination with an artificial spinal disc replacement device. Virtually all of the various embodiments disclosed here could be utilized, in various ways, in combination with artificial disc replacement devices, as well as nucleus repair systems and replacement devices, interbody spacers, dynamic stabilization devices, articulating rod and screw systems, posterior ligament or annular repair and/or augmentation devices, interspinous spacers, facet resurfacing devices, and the like, with varying utility.
Various embodiments of the present invention desirably link the facet replacement prosthesis with the artificial disc replacement prosthesis in some manner. This link can be integral, such that the two components are “hard linked” together (either inflexibly, or flexibly—to allow and/or disallow articulation between components), or the components can be “soft linked” together, to allow movement and/or displacement between the components to some desired limit. If desired, at least one end of the linking device can comprise a polyaxial-type connection to connect to one or components of the facet replacement prosthesis. In alternate embodiments, the link may similarly pass through one or more openings formed through the various facet replacement components.
Desirably, the limitations and disadvantages inherent with many prior art facet replacement systems, as well as many artificial disc replacement systems, can be reduced, minimized and/or eliminated by the combination of such systems into a single, functional spinal unit joint replacement system. For example, the opportunity for the disc replacement to migrate and/or displace relative to the vertebral bodies during the life of the implantation may be reduced and/or eliminated by linking the disc replacement to the facet replacement prosthesis. Similarly, linking the disc replacement to the facet replacement may confer the added benefit of reducing (or redistributing) loading of the anchors (pedicle, lamina, spinous process and/or some combination thereof) of the facet replacement prosthesis, or visa versa (attachment of the disc replacement to the facet replacement affects loading of the disc replacement). Moreover, the forces acting on one component of the device (i.e., the artificial disc replacement device) may be balanced and/or negated by various forces acting on another component of the device (i.e., the facet joint replacement device), thus reducing and/or balancing the forces acting on the entire construct and/or its anchoring devices.
In one embodiment, the connection mechanism between the linkage and the artificial disc replacement can further serve to augment the stability and long-term viability of the artificial disc replacement. In this embodiment, the linkage comprises a longitudinally-extending arm which travels along the endplate of the vertebral body, through an opening formed in the artificial disc replacement, and extending further along the endplate. Desirably, this arm will serve to distribute loading of the disc on the endplate, reducing and/or eliminating subsidence of the disc replacement into and/or through the vertebral endplate (in a manner similar to using a rescue ladder on thin ice to distribute the weight of the rescuer). Various embodiments of the arm can comprise a flattened or half-circular cross-section, with the flattened section (towards the endplate) comprising a bioactive and/or in-growth surface to promote biofixation to the surrounding tissues. The linkage arms could comprise flexible or rigid materials.
In one alternate embodiment, the linkage arms are desirably non-parallel and/or non symmetric between the upper and lower linkage arms (which are linked to the upper and lower components of the disc replacement, respectively), so as to provide both lateral and anterior/posterior support to prevent migration of the disc replacement device and/or more easily allow controlled displacement of the disc replacement upon manipulation of the linkage arms.
If desired, a displaceable/repositionable disc replacement system (as described in the paragraph above) could incorporate one or more “settings” that would allow the physician to control, limit, reduce, increase or prevent motion of the disc replacement and/or facet replacement devices (to promote some clinical benefit, including inducing spinal fusion, limit articulation to promote healing of spinal tissues, limit or allow micro motion to promote bony in-growth into devices, or some other desired clinical outcome).
In various embodiments, the linkage between the facet replacement prosthesis and the disc replacement device facilitates positioning (or repositioning) of the respective prosthesis/device relative to each other, to more easily allow matching (or compatibility) of the kinematics and/or performance characteristics of the prosthesis/devices to each other (desirably, to emulate the natural spinal joint).
In various embodiments, the disc replacement device could incorporate openings or other docking features that could be utilized, at a later date (such as, for example, during a subsequent surgical procedure), to attach a facet replacement device (as disclosed herein) to the disc replacement. For example, where the disc replacement has been implanted, and the patient has healed from that surgery, but suffers spinal degeneration in the future (such as, for example, degenerated facets, spinal stenosis and/or spondylolitic slip of the treated spinal level), the level can be reopened, the facet replacement device attached to the existing disc replacement implant, and the surgical procedure completed. A similar arrangement could be contemplated for a facet replacement device that is initially implanted with openings or docking features that are later utilized during subsequent implantation of an artificial disk replacement prosthesis.
Various alternative embodiments of the present invention relate to laminar and/or pedicle based systems for replacing natural facets, the systems anchored to the vertebral bodies, with or without using cement and/or bony ingrowth surfaces to augment fixation.
As will be appreciated by those skilled in the art, the various embodiments disclosed herein can be adapted to account for location, length and orientation of, for example, the laminar passage created by the surgeon during implantation. The various embodiments can also be adapted to account for an individual patient's anatomical constraints. Thus, a limited number of component sizes and/or shapes can be configured from a kit to accommodate a large variety of anatomical variations possible in a patient. For example, a kit including a cephalad implant can include cephalad implants having various lengths from 20 mm to 70 mm, in, for example, 5 or 10 mm increments to accommodate passages/lamina having different lengths/thicknesses. Similarly the depth of apertures that accommodate a component can also be adapted to accommodate a patient.
Another advantage of various embodiments is that the use of the lamina and spinous process as an anchor point for the device enables the device to be implanted while avoiding the pedicles of the vertebral body. Alternatively, it may be desirous to utilize the pedicles of the vertebral body as an anchor point for the device while avoiding the lamina and spinous process. In various embodiments, the combination of translaminar and pedicular attachment (or a hybrid of both) may be most advantageous to the patient. For example, where facet replacement devices are implanted into multiple spinal levels, such as implantation of facet replacement devices across each of the L4-S1 levels, the use of a cephalad translaminar facet replacement device (in the L4 vertebra) in combination with a caudad pedicular-anchored facet replacement device (in the L5 vertebra) may be used in the L4-L5 level, while the use of a cephalad pedical-anchored facet replacement device (in the L5 vertebra—potentially utilizing the same pedicle anchors as for the caudad components of the L4-L5 level) in combination with a caudad pedicular-anchored device (in the sacrum) may be used in the L5-|S1 level. Such an arrangement would thus obviate the need to use the significantly weaker L5 lamina as an anchoring point, yet allow multiple level replacement of the facet joints. Such a hybrid device could, of course, similarly be used in conjunction with all manner of spinal treatment devices, including artificial disc replacements of one or more spinal levels, annular repair, nucleus replacement, dynamic stabilization, ligament repair and replacement, interspinous spacer, articulating rod and screw systems, and/or adjacent level fusion devices.
Additional disclosure useful in understanding the scope and teaching of the invention as it relates to intervertebral discs is in U.S. Patent Pubs. US 2005/0055096 A1 to Serhan et al., for Functional Spinal Unit Prosthetic; and US 2005/0033434 A1 to Berry for Posterior Elements Motion Restoring Device.
Further disclosures useful in understanding the scope and teaching of the invention are included in U.S. Pat. No. 6,610,091, to Mark A. Reiley, for Facet Arthroplasty Devices and Methods; U.S. Publication Nos. US 2005/0283238 A1, to Mark A. Reiley, for Facet Arthroplasty Devices and Methods; US 2005/0234552 A1, to Mark A. Reiley, for Facet Arthroplasty Devices and Methods; US 2005/0267579 A1, to Mark A. Reiley, et al., for Implantable Device For Facet Joint Replacement; US 2006/0009849 A1, to Mark A. Reiley, for Facet Arthroplasty Devices and Methods; US 2006/0009848 A1, to Mark A. Reiley, for Facet Arthroplasty Devices and Methods; US 2006/0009847 A1, to Mark A. Reiley, for Facet Arthroplasty Devices and Methods; US 2004/0006391 A1, to Mark A. Reiley, for Facet Arthroplasty Devices and Methods; US 2004/0111154 A1, to Mark A. Reiley, for Facet Arthroplasty Devices and Methods; US 2004/0049276 A1, to Mark A. Reiley, for Facet Arthroplasty Devices and Methods; US 2005/0251256 A1, to Mark A. Reiley, for Facet Arthroplasty Devices and Methods; US 2004/0049273 A1, to Mark A. Reiley, for Facet Arthroplasty Devices and Methods; US 2004/0049281 A1, to Mark A. Reiley, for Facet Arthroplasty Devices and Methods; US 2004/0049275 A1, to Mark A. Reiley, for Facet Arthroplasty Devices and Methods; U.S. Pat. No. 6,949,123 B2, to Mark A. Reiley, for Facet Arthroplasty Devices and Methods; U.S. Publication Nos. US 2004/0049274 A1, to Mark A. Reiley, for Facet Arthroplasty Devices and Methods; US 2004/0049278 A1, to Mark A. Reiley, for Facet Arthroplasty Devices and Methods; US 2004/0049277 A1, to Mark A. Reiley, for Facet Arthroplasty Devices and Methods; US 2005/0137706 A1, to Mark A. Reiley, for Facet Arthroplasty Devices and Methods; US 2005/0137705 A1, to Mark A. Reiley, for Facet Arthroplasty Devices and Methods; US 2005/0149190 A1, to Mark A. Reiley, for Facet Arthroplasty Devices and Methods; US 2005/0043799 A1, to Mark A. Reiley, for Facet Arthroplasty Devices and Methods; US 2002/0123806 A1, to Mark A. Reiley, for Facet Arthroplasty Devices and Methods; U.S. Pat. No. 6,974,478, to Mark A. Reiley, et al., for Prostheses, Systems, and Methods for Replacement of Natural Facet Joints with Artificial Facet Joint Surfaces; US 2005/0240265 A1, to Mark Kuiper, et al., for Crossbar Spinal Prosthesis Having a Modular Design and Related Implantation Methods; US 2005/0119748 μl, to Mark A. Reiley, et al., for Prostheses, Systems, and Methods for Replacement of Natural Facet Joints with Artificial Facet Joint Surfaces; US 2005/0027361 A1, to Mark A. Reiley for Facet Arthroplasty Devices and Methods; US 2005/0240266 A1, to Mark Kuiper, et al., for Crossbar Spinal Prosthesis Having a Modular Design and Related Implantation Methods; US 2005/0261770 A1, to Mark Kuiper, et al., for Crossbar Spinal Prosthesis Having a Modular Design and Related Implantation Methods; US 2004/0230201 A1, to Hansen Yuan, et al., for Prostheses, Systems, and Methods for Replacement of Natural Facet Joints with Artificial Facet Joint Surfaces; US 2005/0143818 A1, to Hansen Yuan, et al., for Prostheses, Systems, and Methods for Replacement of Natural Facet Joints with Artificial Facet Joint Surfaces; US 2005/0010291 A1, to David Stinson, et al., for Prostheses, Systems, and Methods for Replacement of Natural Facet Joints with Artificial Facet Joint Surfaces; U.S. application Ser. No. 11/275,447 to David Stinson, et al., for Prostheses, Systems, and Methods for Replacement of Natural Facet Joints with Artificial Facet Joint Surfaces; US 2004/030304 A1, to Hansen Yuan, et al., for Prostheses, Systems, and Methods for Replacement of Natural Facet Joints with Artificial Facet Joint Surfaces; US 2005/0131406 A1, to Mark A. Reiley, et al., for Polyaxial Adjustment of Facet Joint Prostheses; US 2005/0240264A1, to Leonard Tokish, et al., for Anti-rotation Fixation Element for Spinal Prostheses; US 2005/0235508 A1, to Teena M. Augostino, et al., for Facet Joint Prostheses Measurement and Implant tools; U.S. application Ser. No. 11/236,323, to Michael J. Funk, For Implantable Orthopedic Device Component Selection Instrument and Methods; U.S. application Ser. No. 11/206,676, to Richard Broman, et al., for Implantable Spinal Device Revision System; US 2006/0041211 A1, to Teena M. Augostino, et al., for Adjacent Level Facet Arthroplasty Devices, Spine Stabilization Systems, and Methods; US 2006/0041311 A1, to Thomas J. McLeer for Devices and Methods for Treating Facet Joints; U.S. application Ser. Nos. 11/140,570, to Thomas J. McLeer, for Methods and Devices for Improved Bonding to Bone; and Ser. No. 11/244,420, to Thomas J. McLeer, for Polymeric Joint Complex and Methods of Use.
While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those killed in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.
This application claims the benefit of U.S. Provisional Application No. 60/664,441, to Michael J. Funk et al, filed Mar. 22, 2005, and entitled “Minimally Invasive Facet Replacement”; U.S. Provisional Application No. 60/719,427, to Michael J. Funk et al., filed Sep. 22, 2005, entitled “Prosthesis, Tools and Methods for Replacement of Natural Facet Joints with Artificial Facet Joint Surfaces”; and U.S. Provisional Application 60/752,277 to Christopher Ralph et al., filed Dec. 20, 2005, entitled “Spinal Joint Replacement Systems”; the disclosures of which are incorporated herein by reference in their entireties.
| Number | Date | Country | |
|---|---|---|---|
| 60664441 | Mar 2005 | US | |
| 60719427 | Sep 2005 | US | |
| 60752277 | Dec 2005 | US |
