Patent Application
20090093843
This disclosure relates generally to spinal implants and spine stabilization systems, and more particularly to apparatus and systems for stabilizing movement between spinous processes.
The human spine consists of segments known as vertebrae linked by intervertebral disks and held together by ligaments. There are 24 movable vertebrae—7 cervical, 12 thoracic, and 5 lumbar. Each vertebra has a somewhat cylindrical bony body (centrum), a number of winglike projections, and a bony arch. The bodies of the vertebrae form the supporting column of the skeleton. The arches are positioned so that the space they enclose forms the vertebral canal. It houses and protects the spinal cord, and within it the spinal fluid circulates. Ligaments and muscles are attached to various projections of the vertebrae.
The spine is subject to abnormal curvature, injury, infections, tumor formation, arthritic disorders, and puncture or slippage of the cartilage disks. Injury or illness, such as spinal stenosis and prolapsed discs may result in intervertebral discs having a reduced disc height, which may lead to pain, loss of functionality, reduced range of motion, and the like. Scoliosis is one relatively common disease which affects the spinal column. It involves moderate to severe lateral curvature of the spine, and, if not treated, may lead to serious deformities later in life. One treatment involves surgically implanting devices to correct the curvature.
Modern spine surgery often involves spinal fixation through the use of spinal implants or fixation systems to correct or treat various spine disorders or to support the spine. Spinal implants may help, for example, to stabilize the spine, correct deformities of the spine, facilitate fusion, or treat spinal fractures.
A spinal fixation system typically includes corrective spinal instrumentation that is attached to selected vertebra of the spine by screws, hooks, and clamps. The corrective spinal instrumentation includes spinal rods or plates that are generally parallel to the patient's back. The corrective spinal instrumentation may also include transverse connecting rods that extend between neighboring spinal rods. Spinal fixation systems are used to correct problems in the cervical, thoracic, and lumbar portions of the spine, and are often installed posterior to the spine on opposite sides of the spinous process and adjacent to the transverse process.
Often, spinal fixation may include rigid (i.e., in a fusion procedure) support for the affected regions of the spine. Such systems limit movement in the affected regions in virtually all directions (e.g., in a fused region). More recently, so called “dynamic” systems have been introduced wherein the implants allow at least some movement (e.g., flexion, extension, lateral bending, or torsional rotation) of the affected regions in at least some directions.
Embodiments of the present disclosure offer devices and systems for stabilizing portions of the spine. Furthermore, embodiments of the present disclosure may provide spinal stabilization utilizing the spinous processes. One embodiment may be directed to an interspinous member for stabilizing movement between adjacent vertebrae, including a body for stabilizing movement between a first spinous process and a second spinous process and two lateral portions extending from the body for engaging the two elongated members positioned lateral to the first spinous process and the second spinous process to stabilize movement between the elongated members. In some embodiments, the body may have a first surface for contact with an inferior portion of the first spinous process and a second surface for simultaneous contact with a superior portion of the second spinous process. In some embodiments, the upper surface has a curved portion for contact with a portion of the inferior portion of a spinous process. In some embodiments, the lower surface has a curved portion for contact with a portion of the superior portion of a spinous process. In some embodiments, each lateral portion is curved to receive a portion of an elongated member such that the lateral portion engages the elongated member. In some embodiments, each lateral portion comprises a receiving portion for receiving a portion of an elongated member.
Another embodiment of the present disclosure is directed to a system for stabilizing movement between two or more vertebrae, including two elongated members for positioning lateral to two spinous processes of the vertebrae, two fasteners for coupling each elongated member to the vertebrae, and an interspinous member for coupling to the two elongated members for positioning between the spinal processes of adjacent spinous processes. In some embodiments, each interspinous member includes a body for stabilizing movement between a first spinous process and a second spinous process, having a first surface for contact with an inferior portion of the first spinous process and a second surface for simultaneous contact with a superior portion of the second spinous process, and two lateral portions extending from the body for engaging the two elongated members positioned lateral to the first spinous process and the second spinous process to stabilize movement between the elongated members. In some embodiments, positioning the lateral portions on the elongated members positions the body to stabilize movement between adjacent spinous processes. In some embodiments, a fastener comprises a bone fastener assembly. In some embodiments, a fastener comprises a hook. In some embodiments, a fastener comprises a bolt for passage through a portion of a spinous process. In some embodiments, a fastener comprises a clamp. In some embodiments, a fastener comprises a universal band. In some embodiments, the two elongated members are connected at both ends and comprise a slot along a portion thereof to accommodate two spinous processes. In some embodiments, a slot formed along a portion of a single rod divides the rod into two elongated members for positioning lateral to two spinous processes. In some embodiments, the two elongated members comprise an engagement feature, wherein one or more interspinous members engage the elongated members at one of the engagement features.
One embodiment of the disclosure is directed to method for stabilizing a portion of a spine, including coupling a first elongated member to a first side of a first vertebra, coupling the first elongated member to the first side of a second vertebra, coupling a second elongated member to a second side of the first vertebra, coupling the second elongated member to the second side of the second vertebra, positioning a body of an interspinous member between adjacent spinous processes such that a first surface of the body contacts an inferior portion of a first spinous process and a second surface contacts a superior portion of a second spinous process, and engaging two lateral portions of the interspinous member to a portion of the two elongated members. In some embodiments, the first or second elongated member spans between the first and second vertebrae in some embodiments, the body stabilizes movement between the adjacent spinous processes. In some embodiments, each lateral portion receives a portion of an elongated member. In some embodiments, the positioning of the lateral portions on the elongated members positions the body to stabilize movement between adjacent spinous processes. In some embodiments, a lateral portion is slidably positioned along the first or second elongated member. In some embodiments, the method includes engaging the interspinous member with an engagement feature on an elongated member. In some embodiments, the method may include coupling an elongated member to a bone fastener assembly or hook implantable in bony tissue. In some embodiments, the method may include coupling an elongated member to a portion of a bolt assembly for penetrating through a portion of a spinous process. In some embodiments, the method may include coupling one of the elongated members to the other elongated member. In some embodiments, the method may include coupling one of the elongated members to the other elongated member with a universal band.
One advantage to implanting this type of system is the decreased number of bone fasteners, which may result in less time in surgery, decreased risk of damage to the spinal cord, spinal column, muscles, blood vessels, nerves, or other tissues or organs, and/or reduced recovery time, decreased complications such as pain or infection, or other surgical or subsequent issues.
These, and other, aspects of the disclosure will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. The following description, while indicating various embodiments of the disclosure and numerous specific details thereof, is given by way of illustration and not of limitation. Many substitutions, modifications, additions or rearrangements may be made within the scope of the disclosure, and the disclosure includes all such substitutions, modifications, additions or rearrangements.
The disclosure and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well known starting materials, processing techniques, components and equipment are omitted so as not to unnecessarily obscure the disclosure in detail. Skilled artisans should understand, however, that the detailed description and the specific examples, while disclosing preferred embodiments of the disclosure, are given by way of illustration only and not by way of limitation. Various substitutions, modifications, additions or rearrangements within the scope of the underlying inventive concept(s) will become apparent to those skilled in the art after reading this disclosure.
A spinal stabilization system may be installed in a patient to stabilize a portion of a spine. Spinal stabilization may be used, but is not limited to use, in patients having degenerative disc disease, spinal stenosis, spondylolisthesis, pseudoarthrosis, and/or spinal deformities; in patients having fracture or other vertebral trauma; and in patients after tumor resection. A spinal stabilization system may be installed using a minimally invasive procedure. An instrumentation set may include instruments and spinal stabilization system components for forming a spinal stabilization system in a patient.
A minimally invasive procedure may be used to limit an amount of trauma to soft tissue surrounding vertebrae that are to be stabilized. In some embodiments, the natural flexibility of skin and soft tissue may be used to limit the length and/or depth of an incision or incisions needed during the stabilization procedure. Minimally invasive procedures may provide limited direct visibility in vivo. Forming a spinal stabilization system using a minimally invasive procedure may include using tools to position system components in the body.
A minimally invasive procedure may be performed after installation of one or more spinal implants in a patient. The spinal implant or spinal implants may be inserted using an anterior procedure, a posterior procedure, a lateral procedure, or any combination thereof. The patient may be turned and a minimally invasive procedure may be used to install a posterior spinal stabilization system. A minimally invasive procedure for stabilizing the spine may be performed without prior insertion of one or more spinal implants in some patients. In some patients, a minimally invasive procedure may be used to install a spinal stabilization system after one or more spinal implants are inserted using a posterior spinal approach.
A spinal stabilization system may be used to achieve rigid pedicle fixation while minimizing the amount of damage to surrounding tissue. In some embodiments, a dynamic spinous process stabilization system may be used to provide stability to two adjacent vertebrae (i.e., one vertebral level).
In one embodiment, a dynamic spinous process stabilization system may be coupled to one or more vertebrae using one or more fasteners. An elongated member may be coupled to the fastener. As used herein, “coupled” components may directly contact each other or may be separated by one or more intervening members.
In one embodiment, a fastener may include a bone fastener assembly. A bone fastener assembly may be positioned in one of the vertebrae to be stabilized. In one embodiment, a fastener may include a hook. A hook may be positioned in one of the vertebrae to be stabilized. An elongated member may be coupled to the hook.
In one embodiment, a fastener may include a bolt. A bolt may be passed through the spinous process of one of the vertebrae to be stabilized. One end of an elongated member may be coupled and secured to the bolt on one side of the spinous process and one end of the other elongated member may be coupled to the bolt on the other side of the spinous process.
In one embodiment, a fastener may include a universal band. In one embodiment, a flexible ligature of a universal band may be looped around a portion of one of the vertebrae to be stabilized and pass through a portion of a universal band body. In one embodiment, an elongated member may be coupled to a collar coupled to portion of the universal band body. In one embodiment, the flexible ligature may be tightened.
In one embodiment, a fastener may include a clamp. In one embodiment, a clamp may be positioned about one of the vertebrae to be stabilized. In one embodiment, an elongated member may be coupled to the clamp and the clamp may be tightened to couple the elongated member to the vertebrae. Alternatively, the ends of both elongated members may be coupled to the clamp and the clamp may be tightened to couple the elongated members to the vertebrae.
In some embodiments, a dynamic stabilization system may be installed between two vertebrae (i.e., a single vertebral level) in a patient. Such a system may be referred to as a single-level stabilization system. In some embodiments, a spinal stabilization system may provide stability to three or more vertebrae (i.e., two or more vertebral levels). A dynamic stabilization system may include one or more fasteners such as bone fastener assemblies, hooks, bolts, universal bands (u-bands), and/or clamps. One or more fasteners may be positioned on each end vertebra of the vertebrae to be stabilized. In one embodiment an elongated member may be coupled to the fasteners.
Embodiments of the dynamic spinal stabilization system disclosed herein are particularly suited for minimally invasive procedures which have many desirable advantages. For example, minimally invasive procedures may reduce trauma to soft tissue surrounding vertebrae that are to be stabilized. In a minimally invasive surgery, only a small opening may need to be made in a patient. As an example, for a single-level stabilization procedure, the surgical procedure may be performed through 2 cm to 4 cm incisions formed in the skin of the patient. In some embodiments, the incision may be above and substantially between the vertebrae to be stabilized. In some embodiments, the incision may be above and between the vertebrae to be stabilized. In some embodiments, the incision may be above and substantially halfway between the vertebrae to be stabilized. A minimally invasive procedure may reduce an amount of post-operative pain felt by a patient as compared to invasive spinal stabilization procedures. A minimally invasive procedure may reduce recovery time for the patient as compared to invasive spinal procedures.
Spinal stabilization systems may be used to correct problems in lumbar, thoracic, and/or cervical portions of a spine. Various embodiments of a spinal stabilization system may be used from the C1 vertebra to the sacrum. For example, a spinal stabilization system may be implanted posterior to the spine to maintain distraction between adjacent vertebral bodies in a lumbar portion of the spine.
Components of spinal stabilization systems may be made of materials including, but not limited to, titanium, titanium alloys, stainless steel, ceramics, and/or polymers. Some components of a spinal stabilization system may be autoclaved and/or chemically sterilized. Components that may not be autoclaved and/or chemically sterilized may be made of sterile materials. Components made of sterile materials may be placed in working relation to other sterile components during assembly of a spinal stabilization system.
Some embodiments of dynamic stabilization systems disclosed herein may provide greater freedom of movement to facilitate the healing process. In some embodiments, dynamic stabilization systems allow for motion such as twisting, lateral bending, torsion, flexion, and extension. In some embodiments, a dynamic stabilization system may be coupled to one or more spinous processes, transverse processes, and/or pedicles.
Each bone fastener 108 provided in an instrumentation set may have substantially the same thread profile and thread pitch. In one embodiment, the thread may have about a 4 mm major diameter and about a 2.5 mm minor diameter with a cancellous thread profile. In some embodiments, the minor diameter of the thread may be in a range from about 1.5 mm to about 4 mm or larger. In some embodiments, the major diameter of the thread may be in a range from about 3.5 mm to about 6.5 mm or larger. Bone fasteners 108 with other thread dimensions and/or thread profiles may also be used. A thread profile of bone fasteners 108 may allow bone purchase to be maximized when bone fastener 108 is positioned in vertebral bone.
As used herein, the term “collar” includes any element that wholly or partially encloses or receives one or more other elements. Collar 112 may enclose or receive elements including, but not limited to, bone fastener 108, closure member 106, ring 110, and/or elongated member 104. In some embodiments, collar 112 may couple two or more other elements together (e.g., elongated member 104 and bone fastener 108). Collar 112 may have any of various physical forms. In some embodiments, collar 112 may have a “U” shape, however it is to be understood that collar 112 may also have other shapes.
In some embodiments, collar 112 may be open or closed. A collar having a slot and an open top, such as collar 112 shown in
In some embodiments, closure member 106 may be coupled to collar 112 of bone fastener assembly 102 to couple elongated member 104 positioned in collar 112 to bone fastener assembly 102. In some embodiments, closure member 106 may be cannulated. In some embodiments, closure member 106 may have a solid central core. In some embodiments, closure member 106 with a solid central core may provide a more secure connection to elongated member 104 than a cannulated closure member 106 by providing contact against elongated member 104 at a central portion of closure member 106 as well as near an edge of closure member 106.
In some embodiments, bone fastener assembly 102 may be a fixed angle fastener.
In some embodiments, one or more biased collars 112 may be used in a spinal stabilization system. In some embodiments, the spinal stabilization systems may be a multi-level system. In some embodiments, biased collars 112 may be used to accommodate the increasing angle of the pedicle corridor for each lumbar vertebra. In some embodiments, the angle may increase by about 5 degrees for each successive lumbar vertebra.
In some embodiments, bone fastener 108 of bone fastener assembly 102A may engage pedicle 164A at pedicle angle φA (phi-Alpha) relative to sagittal plane 168. Pedicle angle φA (phi-Alpha) may range between about 13 degrees and about 17 degrees. In some embodiments, collar 112A of bone fastener assembly 102A may be unbiased. Pedicle angle φβ (phi-Beta) may range between about 18 degrees and about 22 degrees. In some embodiments, collar 112B may have a bias angle β (Beta) of about 5 degrees. In some embodiments, bone fastener assembly 102B may engage pedicle 164B at pedicle angle φβ (phi-Beta). Because the bias of collar 112B is approximately equal to the difference between the pedicle angles of the two vertebrae, slots 150A and 150B in bone fastener assemblies 102A and 102B, respectively, may be generally aligned when both bone fasteners 108 are in neutral positions.
In some embodiments, angulation of either or both collars 112 of the bone fastener assemblies 102 may allow fine adjustment of engagement angles of the bone fasteners 108. In some embodiments, angulation of collars 112 may allow adjustment in the orientation of bone fasteners 108 in a sagittal plane (i.e., to conform to lordosis of a spine) while still allowing collars 112 to be easily coupled with elongated member 104. In some embodiments, elongated member 104 may be disposed in slots 150A and 150B and coupled to collars 112 by closure members. In some embodiments, a flexible driver or a polyaxial driver (e.g., a driver with a universal joint) may be used to drive the heads of bone fasteners 108 from a position that is off-axis from bone fasteners 108 to reduce the size of an opening of the body needed to implant the spinal stabilization system.
In some embodiments, various instruments may be used in minimally invasive spine stabilization procedures to form a spinal stabilization system in a patient. The instruments may include, but are not limited to, positioning needles, guide wires, dilators, bone awls, bone taps, sleeves, drivers, tissue wedges, elongated member length estimating tools, mallets, tissue retractors, tensioning tools, and tissue dilators. In some embodiments, the instruments may be provided in an instrumentation set. In some embodiments, the instrumentation set may also include components of the spinal stabilization system.
In some embodiments, instruments used to install a spinal stabilization system may be made of materials including, but not limited to, stainless steel, titanium, titanium alloys, ceramics, and/or polymers. Some instruments may be autoclaved and/or chemically sterilized. Some instruments may include components that cannot be autoclaved or chemically sterilized. Components of instruments that cannot be autoclaved or chemically sterilized may be made of sterile materials. The sterile materials may be placed in working relation to other parts of the instrument that have been sterilized.
In some embodiments, elongated member 104 may be cut to length and contoured as desired. In some embodiments, a medical practitioner may use experience and judgment to determine curvature of elongated member 104 for a patient. In some embodiments, a desired curvature for elongated member 104 may be determined using fluoroscopic imaging.
In some embodiments, elongated members 104 may have shapes including, but not limited to, straight, bent, curved, s-shaped, and z-shaped.
In some embodiments, insertion of elongated member 104 may not be visualized subcutaneously. In some embodiments, a positioning tool may be used to guide elongated member 104 into collars 112. In some embodiments, with slight pressure, elongated member 104 may be rotated subcutaneously into a substantially horizontal position and seated in collars 112.
In some embodiments, spinal stabilization system 100 may include hook 10.
In some embodiments, hook 10 may include assembly head 22 suitable for securing hook 10 to elongated members 104. In some embodiments, curved portion 20 and assembly head 22 may be manufactured separately. In one embodiment, assembly head 22 may be mechanically joined to curved portion 20. In one embodiment, assembly head 22 may be threadably joined to curved portion 20. In one embodiment, assembly head 22 may be compression fit to curved portion 20. In one embodiment, assembly head 22 may be chemically joined to curved portion 20. In one embodiment, assembly head 22 may be glued to curved portion 20. In one embodiment, assembly head 22 may be epoxied to curved portion 20. In some embodiments, assembly head 22 may be thermally joined to curved portion 20. In one embodiment, assembly head 22 may be welded to curved portion 20. In one embodiment, assembly head 22 may be sweat-locked to curved portion 20.
In some embodiments, assembly head 22 and curved portion 20 may be manufactured as a single unit to form hook 10. In one embodiment, assembly head 22 and curved portion 20 may be cast. In one embodiment, assembly head 22 and curved portion 20 may be machined as a single unit.
In some embodiments, hook 10 may have transverse and longitudinal dimensions lying in the range 5 millimeters (mm) to 20 mm. In some embodiments, assembly head 22 of hook 10 may have an outer shape substantially cylindrical about the axis x-x′. In some embodiments, assembly head 22 may have an inner surface with helical thread 24 and may have slot 26, which may define two upwardly extending side walls 28, 28′.
In some embodiments, as can be seen in
In some embodiments, as can be seen in
In some embodiments, assembly head 22 may include two orifices 21, 21′ situated in the side walls 28, 28′. During a surgical operation, the surgeon may use an instrument for inserting, advancing, adjusting, or otherwise positioning hook 10. In some embodiments, an instrument may have two protrusions receivable in orifices 21, 21′ in order to hold hook 10.
In some embodiments, once the surgeon has determined the type of elongated member 104, retention means 40 may be positioned in assembly head 22 to retain elongated member 104 in assembly head 22 before it is locked. An advantage is the ability for the surgeon to adjust the position of elongated member 104 and secure it without holding elongated member 104. In some embodiments, while the position of elongated member 104 is being adjusted, elongated member 104 can move in translation in retention means 40 and can also pivot about its own axis. Meanwhile, retention means 40 prevents elongated member 104 from escaping from assembly head 22.
In some embodiments, retention means 40 is in the form of clip insert 40. Several types of insert are available corresponding to elongated members 104 of different diameters. Advantageously, various inserts 40 can be fitted in the same assembly head 22.
In some embodiments, hook 10 may include closure member 106. Closure member 106 may have a form of a cylindrical part of diameter slightly smaller than the inside diameter of the opening in assembly head 22. In some embodiments, bottom portion of closure member 106 may have thread 52 to enable it to be secured to assembly head 22. In some embodiments, closure member 106 may be coupled to assembly head 22 by engaging threads 52 on closure member 106 with threads 24 in assembly head 22 and rotating closure member 106 through one-fourth of a turn.
Retaining member 40 may have an opening 44 of diameter substantially equal to the diameter of elongated member 104, and for selected contact with elongated member 104. In some embodiments, this engagement may be achieved by applying a small amount of force on elongated member 104 such that extensions 46 may be biased outward from an original position to provide sufficient clearance for a portion of elongated member 104 to seat in retaining member 40. In some embodiments, once elongated member 104 passes a certain point, extension 46 may be able to return to the original position and the inward force provided by extensions 46 retains elongated member 104 in retaining member 40.
In some embodiments, once elongated member 104 is properly in position, the surgeon may proceed to lock it in position. In some embodiments, assembly head 22 may include helical thread 24 as mentioned above for rotatable engagement of threads 52 on closure member 106. In some embodiments, closure member may have a generally cylindrical shape and possesses an “artillery” type thread 52 suitable for co-operating with the helical thread 24 of assembly head 22.
In some embodiments, when closure member 106 is threaded into assembly head 22, bottom surface 54 (depicted in
In some embodiments, the use of a thread of the “artillery” type may present the advantage of reducing radial force while tightening closure member 106.
In some embodiments, even if there is any residual force tending to space walls 28, 28′ apart, retaining member 40 may continue to hold elongated member 104, because retaining member 40 and assembly head 22 may be mechanically decoupled, i.e., the mechanical forces to which assembly head 22 is subjected are not transmitted to retaining member 40.
In some embodiments, when closure member 106 couples hook 10 to elongated member 104 in a locked position (See, e.g.,
Similarly, in some embodiments, there are no additional parts (e.g., hooping rings) on the outside surface of assembly head 22 that might present sharp edges that could damage surrounding tissue.
In some embodiments, hook 10 may present smooth surfaces of other shapes, of the “smooth profile” type, that may be inserted reliably in the human body without any risk of provoking internal lesions. In some embodiments, hook 10 may be implanted in a portion of a vertebra. In some embodiments, hook 10 may be implanted in a spinous process. In some embodiments, hook 10 may be implanted in a transverse process. In some embodiments, hook 10 may be implanted in a pedicle.
In some embodiments, a fastener such as a clamp may be useful for coupling elongated member 104 to a portion of a spine.
In some embodiments, clamp 390 may include transverse elongate part 396 of axis A defining a mean plane PM and presenting two opposite ends 398, 400. In some embodiments, two ends 398, 400 may be substantially mirror images of each other about a plane of symmetry P which intersects transverse elongate part 396 orthogonally. In some embodiments, each end 398 and 400 may have first main face 402 and second main face 404, together with end edge 405. In some embodiments, two connection elements 406 and 408 may be suitable for connection to ends 398 and 400. In some embodiments, ends 398 and 400 may have respective anchor means 410 and 412 of spherical shape projecting from second main faces 404.
In some embodiments, ends 398 and 400 may include first recesses 414 and second recesses 416 oriented away from first recesses 414. In some embodiments, first and second recesses 414 and 416 may be spaced apart from each other by a first distance. In some embodiments, first recesses 414 may be oriented on transverse part 396. In some embodiments, first and second recesses 414 and 416 may be positioned on first and second main faces 402 and 404. In some embodiments, an axis traveling through first and second recesses 414 and 416 may define a line that is substantially perpendicular to transverse part 396.
In some embodiments, connection elements 406 and 408 may form a substantially U-shaped part having free ends 418 and 420 spaced apart from each other by a distance corresponding to the distance between first and second recesses 414 and 416. In some embodiments, connection elements 406 and 408 may be male threaded for engaging female threaded members 422 and 424. In some embodiments, free ends 418 and 420 of connection elements 406 and 408 may be inserted into first and second recesses 414 and 416 with connection elements 406 and 408 coming respectively into register with the first main faces 402 of transverse part 396. In some embodiments, once free ends 418 and 420 have been inserted through first and second recesses 414 and 416 so as to project from second main face 404, threaded members 422 and 424 may be threadably engaged to retain connection elements 406 and 408 and to prevent transverse elongate part 396 from moving relative to the vertebra.
In some embodiments, the shape of second recess 416 may facilitate mounting connection elements 406 and 408 on transverse part 396. In some embodiments, the shape of second recesses 416 may make mounting quicker, due to second recess 416 opening out into edge face 405 and forming an oblong hole. In some embodiments, when transverse part 396 is in the installation position, threaded members 424 may be pre-mounted on free ends 420 of each connection member 406 and 408. In some embodiments, connection member 406 and 408 may be presented in a plane parallel to the plane P, with free end 420 directed towards second recess 416 so that connection member 406 and 408 may slope relative to the mean plane PM. When implanted in the body, connection member 406 and 408 may be parallel to the plane AR. In some embodiments, connection members 406 and 408 may engage transverse part 396 substantially parallel to the mean plane PM so that threaded member 424 may seat against second face 404. In some embodiments, this may enable connection members 406 and 408 to be pivoted about the point where threaded member 424 seats against second face 404, so that free end 418 which is initially situated facing first face 402 may engage recess 414. In some embodiments, free end 418 may be subsequently held in place by threaded member 422. In some embodiments, when connection member 406 or 408 pivots, it may be suitable for coupling with a process situated facing first face 402.
In some embodiments, connection part 406 and 408 may be deformable to conform against the outline of an object to provide better retention. In some embodiments, connection members 406 and 408 may be manufactured from polymers. In some embodiments, connection members 406 and 408 may be manufactured from polyethylene. In some embodiments, connection members 406 and 408 may be manufactured from biocompatible materials. In some embodiments, connection members 406 and 408 may be manufactured from single strands of material or multiple strands functioning as a single strand. In some embodiments, connection members 406 and 408 may be manufactured to conform to portions of the spine. In some embodiments, connection members 406 and 408 may be manufactured to conform to portion(s) of transverse processes 438 as depicted in
In some embodiments, ends 418 and 420 of connection part 406 and 408 may include connection means and adjustment means that are suitable for the material. In some embodiments, ends 418 and 420 of connection part 406 and 408 may be crimped in a rigid material element suitable for being threaded or for constituting a shoulder (see e.g., shoulder 448 of
In some embodiments, threaded members 422 and 424 may be irreversibly secured to ends 418 and 420 of connection parts 406 and 408 so that prolonged traction exerted on connection parts 406 and 408 by threaded members 422 and 424 does not cause them to separate.
In some embodiments, anchors 410 and 412 having substantially spherical heads may be situated on second main surfaces 404, between first and second recesses 414 and 416. In some embodiments, anchors 410 and 412 may be securely connected to transverse part 396 so that the mechanical forces exerted on anchors 410 and 412 can move transverse part 396 without leading to separation. In some embodiments, anchors 410 and 412 may be welded, machined, or otherwise securely connected to transverse part 396.
In some embodiments, transverse parts 396 may seat against posterior walls of vertebrae V1 and V2 substantially perpendicular to the axis AR of the spine. In some embodiments, transverse parts 396 may be held in this position by means of connection parts 408 and 406 whose free ends 418 and 420 may be held in first and second recesses 414 and 416 by means of threaded members 422 and 424 which press against second main faces 404. In some embodiments, tightening threaded members 422 and 424 about free ends 418 and 420 of connection parts 406 and 408, the bottoms of connection parts 406 and 408 may be pulled against the anterior walls 438 of transverse processes 432 and 434, and consequently ends 398 and 400 of transverse parts 396 may be pulled towards transverse processes 434 and 432. In some embodiments, transverse part 396 may be held on either side of the vertebra and against its posterior wall. In some embodiments, transverse part 396 may be completely prevented from moving relative to the vertebra. In some embodiments, threaded members 422 and 424 may be tightened to compress the bony wall a selected amount to further aid retention.
In some embodiments, once clamps 390 have been secured to vertebrae V1 and V2, receivers 392 coupled to elongated member 104 may be positioned and clamped on anchors 410 and 412 on both sides of the spine. In some embodiments, receivers 392 may be held in a fixed position relative to anchors 410 and 412 and elongated member 104 may be held in a fixed orientation relative to receivers 392 so that anchors 410 and 412 may be prevented from moving relative to one another. Consequently, vertebrae V1 and V2 may be held laterally in positions that are fixed relative to one another.
In some embodiments, connection elements 406 and 408 may be engaged solely around the transverse processes 432 and 434. The vertebrae shown in those figures do not carry any ribs. In some embodiments, clamps 390 may be coupled to vertebrae having ribs connected thereto. In some embodiments, connection parts 406 and 406 may have a length greater than connection parts 406 and 408 used for vertebrae that do not carry ribs. In some embodiments, longer connection parts 406 and 408 may be engaged around the ribs so that their bottoms bear against the anterior walls of the ribs and so that, as in the preceding embodiments, free ends 418 and 420 may pass through first and second recesses 414 and 416 of transverse part 396 in order to be secured thereto.
In some embodiments, receivers 392 may be mounted on the spherical heads 412 on both sides of the spine.
In some embodiments, connection parts 440 and 442 may have free end 444 and anchor 450. In some embodiments, free end 444 may be threaded to engage threads on threaded member 422. In some embodiments, free end 446 may include shoulder 448 surmounted by anchor 450.
In some embodiments, anchor 410 and 412 may be joined to transverse part 396 together with connection parts 406 and 408 with which it forms an integral part. In some embodiments, fitting of transverse part 396 to vertebra V1 or V2 may be simplified and more firmly anchor elongated member 104 to the vertebrae.
In some embodiments, universal band 460 may couple to elongated member 104 by capturing elongated member 104 between two longitudinal members 464 and 470 such that a portion of ligature 492 may be pressed against elongated member 104.
In some embodiments, pin 482 and elongated member 104 may be substantially perpendicular to the transverse process such that ligature 492 may need to be partly twisted in order to insert it into the passage 498 and between pin 482 and the point at which it contacts the transverse process.
In some embodiments, wall 508 of elongated member 104 may bear on top of elongated member 104 and one or more of walls 501, 502 and 506 may press flexible ligature 492 against elongated member 104. In some embodiments, closure member 106 may drive longitudinal members 464 and 470 forcibly against elongated member 104 and simultaneously against ligature 492, which may also be forcibly pressed against elongated member 104.
In some embodiments, passage 498 may have a width near orifice 504 greater than a section in the vicinity of the orifice 490. In some embodiments, the width of passage 498 may progressively decrease in the direction from orifice 504 to orifice 490. In some embodiments, flexible ligature 492 may be therefore progressively compressed around a portion of elongated member 104 with a pressure that increases in the direction from orifice 504 towards orifice 490.
In some embodiments, flexible ligature 492 may have a first end 494 that may be ligated around pin 482, and second end 496 that may be inserted into passage 498 between elongated member 104 and internal walls 500 and 501 of longitudinal members 464 and 470 and external wall of elongated member 104. In some embodiments, second longitudinal member 470 may include second orifice 504 through which ligature 492 may pass.
In some embodiments, flexible ligature 492 may be an elongate flexible member capable of conforming to the contour of the parts that it must connect. In some embodiments, flexible ligature 492 may be a flexible strip of substantially constant width and thickness whose first end may be ligated to pin 482, the ligature surrounding the transverse process of the vertebra being inserted through connecting part 462. In some embodiments, ligature 492 may be manufactured from a polymer. In some embodiments, ligature 492 may be manufactured from polyester. In some embodiments, ligature 492 may be manufactured from DACRON polyester. In some embodiments, the thickness of the flexible ligature 492 may be substantially rectangular. In some embodiments, flexible ligature 492 may be made from a flexible material such as polyester that may be lightly crushed locally to immobilize it with a clamping effect.
In some embodiments, universal band 460 may be fixed in position against posterior wall 510 of the vertebra despite these partially twisted portions, the ligature 492 being forcibly tensioned by pulling second end 496. In some embodiments, universal band 460 may not be fixed against a portion of the spine.
In one embodiment of the present disclosure, dynamic stabilization system 100 may include two elongated members 104 positioned on either side of the ridge formed by the spinous processes. Unlike prior art systems, however, bone fastener assemblies 102, hooks 10, bolts, clamps 390 or universal bands 460 may not be coupled to each vertebra. For example, in one embodiment depicted in
In some embodiments, dynamic stabilization system 100 may include one or more interspinous members 80. In some embodiments, interspinous members 80 may be coupled to one or both of elongated members 104. In some embodiments, body 82 of interspinous member 80 may be inserted or otherwise positioned between the spinous processes of adjacent vertebrae to stabilize movement between the spinous processes.
In some embodiments, the positioning of interspinous members 80 may provide stabilization and control movement between adjacent spinous processes. In some embodiments, the size, material, orientation, or any combination of body 82 may stabilize movement between adjacent spinous processes. In some embodiments, the positioning of lateral portions 88 on elongated members 104 may position body 82 of interspinous member 80 to stabilize movement between adjacent spinous processes. For example, in some embodiments, positioning lateral portions 88 closer to the lower of two spinous processes may effectively position body 82 of interspinous member 80 to provide more pressure (i.e., support) to the lower spinous process and less pressure (i.e., support) to the adjacent upper spinous process during flexion of the spine. In this example, the patient may have more support during one spinal movement than another (e.g., more flexion than extension) or one spinous process may be more supported or constrained than adjacent spinous processes.
In some embodiments, interspinous members 80 may have body 82 which may be deformable to stabilize movement. In some embodiments, body 82 may be deformed during contact with an inferior surface of a spinous process. In some embodiments, body 82 may return to its original state or a neutral state once pressure is relieved. In one embodiment, upper surface 84 and lower surface 85 may have any profile useful for contacting a spinous member. In one embodiment, body 82 may be manufactured from any material useful for providing dynamic support to a spine. In some embodiments, body 82 may be manufactured from PEEK (polyetheretherketone), UHMWPE (Ultra-High Molecular Weight Polyethylene), or any polymer or ceramic to provide dynamic support. In some embodiments, body 82 may be manufactured from a single material. In some embodiments, body 82 may be manufactured having constant properties such as density or elasticity. In some embodiments, body 82 may be manufactured having varying density. In some embodiments, body 82 may be manufactured from two or more materials. In some embodiments, body 82 may be manufactured with a core manufactured from one material or process and an outer region manufactured from a second material. In some embodiments, body 82 may be manufactured such that body 82 and/or interspinous member 80 may be implanted and then injected, treated, coated, shaped, filled, or otherwise modified to produce a final body 82 with selected geometry, elasticity, density, or other characteristic useful for controlling movement between adjacent vertebrae. In some embodiments, body 82 may be manufactured having a hollow core and injected with a fluid once implanted such that body 82 is positioned between adjacent vertebrae and upper surface 84 and lower surface 85 contact the spinous processes of adjacent vertebrae. In some embodiments, a set of interspinous members 80 having bodies 82 of different sizes, thicknesses, elasticity, density, core size, material, or other characteristics such that an appropriate interspinous member 80 may be selected. Advantageously, interspinous member 80 may be selected for stabilizing movement and then positioned between spinous processes to help stabilize the spine.
In some embodiments, interspinous member 80 may stabilize movement by limiting the maximum amount of travel between two adjacent vertebrae. In some embodiments, interspinous member 80 may stabilize movement by limiting the maximum amount of travel due the geometry of body 82. In some embodiments, interspinous member 80 may stabilize movement by limiting the maximum amount of travel due to positioning on elongated members 104.
In some embodiments, body 82 may stabilize movement by providing progressive resistance to cushion or dampen movement between adjacent vertebrae. In some embodiments, body 82 may have an associated spring constant. For example, in one embodiment first interspinous member 80 positioned between a first vertebra and a second vertebra may have body 82 with a stiff spring constant for greater rigidity, and second interspinous member 80 positioned between the second vertebra and a third vertebra may have a body 82 with a weak spring constant for greater flexibility. In this embodiment, the spine may have greater flexibility between the second and third vertebrae than between the first and second vertebrae. In some embodiments, body 82 may stabilize movement by providing a progressive resistance and may further have a maximum amount of travel. The selection of a spring constant and/or maximum amount of travel may depend or be determined based on patient comfort and health, surgical goals, or other criteria. In some embodiments, body 82 may stabilize movement by limiting the rate of movement between adjacent vertebrae. In other words, an interspinous member 80 positioned between two vertebrae may not limit the range of travel but may limit how fast the vertebrae may travel. In some embodiments, body 82 may stabilize movement by limiting the maximum rate at which adjacent vertebrae may move relative each other but may not limit the range of motion. In some embodiments, body 82 of interspinous member 80 may stabilize one or more directions of movement. In some embodiments, body 82 may have generally flat surfaces 84 and 85 that may not affect rotational movement. In some embodiments, body 82 may have concave surfaces 84 and 85 that may impede rotational movement. In some embodiments, body 82 may have asymmetric surfaces 84 and 85 that may bias movement toward one side.
In some embodiments, elongated members 104 may be coupled to one or more vertebrae. In some embodiments, an elongated member may be coupled to a vertebra using bone fastener assembly 102. In some embodiments, bone fastener assembly 102 may be implanted in a pedicle, a spinous process, or a transverse process.
In some embodiments, interspinous member 80 may stabilize movement between elongated members 104. In some embodiments, lateral portions 88 and body 82 may form a cross-link mechanism for stabilizing movement between elongated members 104. In some embodiments, lateral portions 88 and body 82 may include a cross-link mechanism useful for stabilizing movement between elongated members 104. As used herein, the term cross-link may refer to a device that connects to both elongated members 104 and limits or eliminates movement of one elongated member 104 relative to the other. In some embodiments, a cross-link may limit or eliminate motion in one or more planes, or about one or more axes of rotation.
In some embodiments, one or more ends of elongated members 104 may be coupled to a vertebra using hook 10. In some embodiments, elongated members 104 may be coupled to one or more universal bands 460 affixed to a portion of a spine.
In some embodiments, elongated members 104 may be coupled to a portion of the spine using clamps (e.g., clamp 390) or similar devices. In some embodiments, elongated members 104 may be coupled directly to a portion of a spinous process. In some embodiments, elongated members 104 may be coupled together. In some embodiments, elongated members 104 coupled together may form a slot to accommodate the spinous processes. In some embodiments, the slot accommodates the spinous processes by providing sufficient clearance for the spinous processes to have some lateral movement. In some embodiments, the slot accommodates the spinous processes by capturing the spinous processes to inhibit lateral movement.
In some embodiments, elongated members 104 may be coupled to one or more universal bands 460 coupled to a spinous process. In some embodiments, elongated members 104 may be coupled together using universal band 460 to accommodate one or more spinous processes by dynamic stabilization system 100. For example, in some embodiments, elongated members 104 may be banded to form a slot to accommodate one or more spinous processes. In some embodiments, the slot accommodates the spinous processes by providing sufficient clearance for the spinous processes to have some lateral movement. In some embodiments, the slot accommodates the spinous processes by capturing the spinous processes to inhibit lateral movement.
Embodiments of interspinous members 80 disclosed herein may be particularly useful in minimally invasive surgery (MIS) procedures or in non-MIS procedures, as desired, and as persons of ordinary skill in the art who have the benefit of the description of the disclosure understand.
In some embodiments, interspinous member 80 may include connection members 87 for maintaining the connection between elongated members 104 and interspinous member 80 to form a cross-link mechanism for stabilizing movement between elongated members 104. One advantage to connection members 87 is that interspinous member 80 may engage elongated member 104 and be positioned such as by sliding lateral portions 88 along elongated members 104 before locking interspinous member 80 in position.
In some embodiments, interspinous members 80 may have lower surface 85 for contact with a superior surface of a spinous process. In one embodiment, lower surface 85 may have an essentially flat portion in contact with a superior surface of a spinous process. In one embodiment, lower surface 85 may have a concave portion in contact with a superior surface of a spinous process. In one embodiment, lower surface 85 may have a convex portion in contact with a superior surface of a spinous process. In one embodiment, lower surface 85 may have a layered, coated, or textured portion for contact with a superior surface of a spinous process.
In some embodiments, interspinous members 80 may have two lateral portions 88 coupled to interspinous body 82, with each lateral portion 88 for engaging one elongated member 104. In some embodiments, lateral portions 88 include receiver portions 90 for receiving elongated members 104. In some embodiments, receiving portion 90 may be an open passage. In one embodiment, receiving portion 90 may be oriented facing lateral to the spine. In some embodiments, receiving portion 90 may be oriented posterior. In one embodiment, receiving portion 90 may be oriented anterior. In some embodiments, receiving portion 90 may connect to a portion of elongated member 104 with a compression fit. In other words, in some embodiments, receiving portion 90 may be temporarily expanded such that elongated member 104 may be positioned inside, then allowed to return to an original or neutral state such that elongated member 104 remains in receiving portion 90. In the embodiment depicted in
In some embodiments, receiving portion 90 may be a closed passage (not shown) which may require interspinous members 80 to couple with elongated members 104 prior to coupling elongated members 104 to bone fastener assemblies 102, hooks 10, bolts 109, clamps 390, or universal bands 460. In some embodiments, interspinous members 80 may couple to elongated members 104 after elongated member 104 has coupled with one or more bone fastener assemblies 102, hooks 10, bolts 109, clamps 390, or universal bands 460.
In some embodiments, elongated members 104 may have engagement features 11. In some embodiments, engagement features 11 may be engaged by lateral portions 88. In some embodiments, engagement features 11 may appear on fluoroscopic images to enable a surgeon to position lateral portion 88 at a desired level.
In some embodiments, interspinous member 80 may include alignment feature 81 for positioning on elongated members 104 such that interspinous member 80 remains in position subsequent surgery. In some embodiments, interspinous member 80 may be aligned with elongated members 104 such that alignment feature 81 seats in slot 71. In some embodiments, once alignment feature 81 has been seated in slot 71, alignment feature 81 may prevent interspinous member 80 from rotating about or disconnecting from elongated members 104. Variations of lateral portions 88 and alignment feature 81 may be possible without departing from the scope of the disclosure.
In some embodiments, a spine stabilization system may include extensions, openings, tabs, recesses, or other features (not shown) to enable bone fasteners, hooks, bolts, clamps, or universal bands to couple elongated members 104 to one or more vertebrae. In some embodiments, once elongated members 104 are coupled to vertebrae, one embodiment of interspinous member 80 may be inserted into the patient. In some embodiments, prior to insertion of interspinous members 80, the tissue wedge or targeting needle may be used to wand between bone fasteners 102 to ensure a clean plane between the bone fasteners 102. An end of interspinous member 80 may be inserted. Inserting interspinous members 80 at an angle or substantially longitudinally allows the length of the incision and/or the area of the tissue plane to remain advantageously small. In some embodiments, interspinous member 80 may be positioned between first and second spinous processes.
In some embodiments of interspinous member 80 having curved lateral portions 88 to receive elongated members 104, lateral portions 88 may be expanded to receive elongated members 104. Once lateral portions 88 have received at least a portion of elongated members 104, lateral portions 88 may be released or otherwise returned to an original orientation to engage elongated members 104. In some embodiments, lateral portions 88 of interspinous member 80 may be curved, angled, bent, or otherwise shaped to receive at least a portion of elongated member 104. In some embodiments, lateral portions 88 may be shaped to extend around elongated members 104 (i.e., form a closed passage).
In some embodiments, lateral portions 88 may be positioned relative to one or both adjacent spinous processes, one or both transverse processes, or some other anatomical landmark. In some embodiments, engagement features 11 may enable lateral portions 88 to securely engage elongated members 104.
Lateral portions 88 of interspinous member 80 may be positioned on portions of elongated members 104. Engagement features on interspinous member 80 may couple to engagement features 11 on elongated members 104. Engagement features may include, but are not limited to, notches, grooves, threads, holes, openings, indentations, alignment marks, pawls, protrusions, and the like.
In the foregoing specification, the disclosure has been described with reference to specific embodiments. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the disclosure as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of disclosure.
The foregoing specification and accompanying figures are for the purpose of teaching those skilled in the art the manner of carrying out the disclosure and should be regarded in an illustrative rather than a restrictive sense. As one skilled in the art can appreciate, embodiments disclosed herein can be modified or otherwise implemented in many ways without departing from the spirit and scope of the disclosure and all such modifications and implementations are intended to be included within the scope of the disclosure as set forth in the claims below.
