Spinal implant system and method

A spinal implant includes a chassis extending along a first axis and including a first thread. A first member extends along a second axis and is pivotably coupled to the chassis. A second member extends along a third axis between and is pivotably coupled to the chassis. A rack includes opposite top and bottom surfaces. A first spur is coupled to the first member such that the first spur engages the top surface. A second spur is coupled to the second member such that the second spur engages the bottom surface. An actuator includes second thread that engages the first thread such that rotation of the actuator move the implant between a first orientation in which the second and third axes extend parallel to the first axis and a second orientation in which the second and third axes extends at an acute angle relative to the first axis.

TECHNICAL FIELD

The present disclosure generally relates to medical devices for the treatment of musculoskeletal disorders, and more particularly to a spinal construct configured for disposal with spaced vertebrae and a method for treating a spine.

BACKGROUND

Spinal disorders such as degenerative disc disease, disc herniation, osteoporosis, spondylolisthesis, stenosis, scoliosis and other curvature abnormalities, kyphosis, tumor, and fracture may result from factors including trauma, disease and degenerative conditions caused by injury and aging. Spinal disorders typically result in symptoms including pain, nerve damage, and partial or complete loss of mobility.

Non-surgical treatments, such as medication, rehabilitation and exercise can be effective, however, may fail to relieve the symptoms associated with these disorders. Surgical treatment of these spinal disorders includes fusion, fixation, corpectomy, discectomy, laminectomy and implantable prosthetics. In procedures, such as, for example, corpectomy and discectomy, fusion and fixation treatments may be performed that employ implants to restore the mechanical support function of vertebrae. This disclosure describes an improvement over these prior technologies.

SUMMARY

In one embodiment, a spinal implant is provided. The spinal implant includes a chassis extending along a first longitudinal axis between opposite first and second ends. The chassis comprises a body and spaced apart first and second extensions extending from the body. The body comprises a first mating part. A first member extends along a second longitudinal axis between opposite first and second ends. The first end of the first member is pivotably coupled to the first end of the chassis. A second member extends along a third longitudinal axis between opposite first and second ends. The first end of the second member is pivotably coupled to the first end of the chassis. A rack is positioned between the extensions. The rack includes opposite top and bottom surfaces. A first spur is coupled to the second end of the first member such that the first spur engages the top surface. A second spur is coupled to the second end of the second member such that the second spur engages the bottom surface. An actuator comprises a second mating part that engages the first mating part such that rotation of the actuator relative to the chassis translates the rack relative to the chassis along the first longitudinal axis to move the implant between a first orientation in which the second and third longitudinal axes extend parallel to the first longitudinal axis and a second orientation in which the second and third longitudinal axes extends at an acute angle relative to the first longitudinal axis.

In one embodiment, a spinal implant is provided. The spinal implant includes a chassis extending along a first longitudinal axis between opposite first and second ends. The chassis comprises a body and spaced apart first and second extensions extending from the body. The body comprises a first mating part. A first member includes a first vertebral engaging surface. The first member extends along a second longitudinal axis between opposite first and second ends. The first end of the first member is pivotably coupled to the first end of the chassis. A second member includes a second vertebral engaging surface. The second member extends along a third longitudinal axis between opposite first and second ends. The first end of the second member is pivotably coupled to the first end of the chassis. A rack is positioned between the extensions. The rack includes opposite top and bottom surfaces. A first spur is coupled to the second end of the first member such that the first spur engages the top surface. A second spur is coupled to the second end of the second member such that the second spur engages the bottom surface. An actuator comprises a second mating part that engages the first mating part. A distance between the vertebral engaging surfaces defines a height of the implant. Rotation of the actuator relative to the members translates the rack relative to the chassis along the first longitudinal axis such that the spurs rotate relative to the chassis and the rack to increase the height of the implant.

In one embodiment, a spinal implant is provided. The spinal implant includes a chassis extending along a first longitudinal axis between opposite first and second ends. The chassis comprises a body and spaced apart first and second extensions extending from the body. The body comprises a female thread. A first member extends along a second longitudinal axis between opposite first and second ends. The first end of the first member is pivotably coupled to the first end of the chassis. A second member extends along a third longitudinal axis between opposite first and second ends. The first end of the second member is pivotably coupled to the first end of the chassis. A rack is positioned between the extensions. The rack includes opposite top and bottom surfaces. The top surface extends at an acute angle relative to the bottom surface such that the rack is wedge-shaped. The top surface comprises a first series of teeth. The bottom surface comprises a second series of teeth. A first spur comprises a first gear that engages at least one of the series of first teeth. A second spur comprises a second gear that engages at least one of the series of second teeth. An actuator comprises a male thread that engages the female thread such that rotation of the actuator relative to the chassis translates the rack relative to the chassis along the first longitudinal axis to move the implant between a first orientation in which the second and third longitudinal axes extend parallel to the first longitudinal axis and a second orientation in which the second and third longitudinal axes extends at an acute angle relative to the first longitudinal axis. The first spur pivots relative to the first member and the rack as the implant moves between the first and second orientations. The second spur pivots relative to the second member and the rack as the implant moves between the first and second orientations.

DETAILED DESCRIPTION

The exemplary embodiments of a surgical system and related methods of use disclosed are discussed in terms of medical devices for the treatment of musculoskeletal disorders and more particularly, in terms of a spinal implant system that includes an expandable interbody implant configured for disposal with spaced vertebrae and a method for treating a spine.

In some embodiments, the expandable interbody implant includes a chassis, opposing endplates, a wedge-shaped rack, opposing spurs and a drive screw. In one embodiment, the rack pushes the spurs apart, increasing the total amount of expansion of the implant. In one embodiment, providing two spurs doubles the amount of expansion compared to implants that include only one spur. In one embodiment, providing two spurs and a wedge-shaped rack increases the total expansion of the implant compared to implants that include only one spur and a linear rack. In some embodiments, a spring is included to pull the endplates together during collapse.

In one embodiment, one or all of the components of the spinal implant system are disposable, peel-pack, pre-packed sterile devices used with an implant. One or all of the components of the spinal implant system may be reusable. The spinal implant system may be configured as a kit with multiple sized and configured components.

The following discussion includes a description of a surgical system and related methods of employing the surgical system in accordance with the principles of the present disclosure. Alternate embodiments are also disclosed. Reference is made in detail to the exemplary embodiments of the present disclosure, which are illustrated in the accompanying figures. Turning toFIGS. 1-4, there is illustrated components of a surgical system, such as, for example, a spinal implant system20.

Various components of spinal implant system20may have material composites, including the above materials, to achieve various desired characteristics such as strength, rigidity, elasticity, compliance, biomechanical performance, durability and radiolucency or imaging preference. The components of spinal implant system20, individually or collectively, may also be fabricated from a heterogeneous material such as a combination of two or more of the above-described materials. The components of spinal implant system20may be monolithically formed, integrally connected or include fastening elements and/or instruments, as described herein.

Spinal implant system20is employed, for example, with a minimally invasive procedure, including percutaneous techniques, mini-open and open surgical techniques to deliver and introduce instrumentation and/or an implant, such as, for example, a corpectomy implant, at a surgical site within a body of a patient, for example, a section of a spine. In some embodiments, spinal implant system20may be employed with surgical procedures, such as, for example, corpectomy and discectomy, which include fusion and/or fixation treatments that employ implants, to restore the mechanical support function of vertebrae.

Spinal implant system20includes an expandable interbody implant22. In some embodiments, implant22includes a core, such as, for example, a chassis24. Chassis24extends along a longitudinal axis X1between an end26and an opposite end28. End26includes a body30extending perpendicular to axis X1and spaced apart extensions32,34that each extend from body30to a wall36. Wall36extends perpendicular to axis X1. An inner surface38of extension32and an inner surface40of extension34define a cavity42. Surface38includes a planar section44and surface40includes a planar section46that faces section44. Sections44,46each extend parallel to axis X1. In some embodiments, body30and wall36are positioned between extension34and extension36to prevent movement of extension34relative to extension36, and vice versa. Body30defines a mating part, such as, for example, a female thread48. Thread48defines a passageway50that is coaxial with axis X1. An outer surface52of extension32includes a planar section54and an outer surface56of extension34includes a planar section58opposite section54. Sections54,58extend parallel to axis X1. In some embodiments, section44, section46, passageway50, section54and/or section58may be disposed at alternate orientations, relative to axis X1, such as, for example, transverse and/or other angular orientations such as acute or obtuse, and/or may be offset or staggered.

Implant22includes a member, such as, for example, an end plate60pivotably coupled to chassis24. Plate60extends along a second longitudinal axis X2between an end62and an opposite end64. Plate60includes a vertebral engaging surface66and an inner surface68opposite surface66. Surface66and/or surface68extend parallel to axis X2. In some embodiments, plate60is tapered toward end64to facilitate insertion of implant22into an intervertebral space, as discussed herein. In some embodiments, surface66may be rough, textured, porous, semi-porous, dimpled, knurled, toothed, grooved and/or polished to facilitate engagement with tissue. In some embodiments, surface66and/or surface68may be disposed at alternate orientations, relative to axis X2, such as, for example, transverse, perpendicular and/or other angular orientations such as acute or obtuse, co-axial and/or may be offset or staggered.

End62includes spaced apart flanges70,72extending from surface68. A pin74extends through flange70and into chassis24and a pin76extends through flange72and into chassis24to couple plate60to chassis24such that plate60is pivotable relative to chassis24about pins74,76. Pin74is coaxial with pin76such that pins74,76define a pivot axis that extends perpendicular to axes X1, X2.

End64includes spaced apart extensions78,80extending from surface68. Extension78includes a slot82and extension80includes a slot84. A spur86is positioned between extension78and extension80such that opposite outer surfaces of spur86directly engage inner surfaces of extensions78,80. One or more pins, such as, for example, a pin88extends through slots82,84and spur86such that spur86is pivotable and/or rotatable relative to plate60about pin88. In some embodiments, slots82,84are elongated to allow pin88to translate within slots82,84such that pin88moves between first ends of slots82,84and opposite second ends of slots82,84as implant22moves between a collapsed or unexpanded orientation and an expanded orientation, as discussed herein. In some embodiments, slots82,84extend parallel to axis X2. In some embodiments, slots82,84may be disposed at alternate orientations, relative to axis X2, such as, for example, transverse, perpendicular and/or other angular orientations such as acute or obtuse, and/or may be offset or staggered. Spur86includes a gear90having a plurality of teeth92configured to engage a rack94of implant22as rack94translates relative to chassis24along axis X1to move implant22between the unexpanded and expanded orientations, as discussed herein.

Implant22includes a member, such as, for example, an end plate96pivotably coupled to chassis24. Plate96extends along a second longitudinal axis X3between an end98and an opposite end100. Plate96includes a vertebral engaging surface102and an inner surface104opposite surface102. Surface102and/or surface104extend parallel to axis X3. In some embodiments, plate96is tapered toward end100to facilitate insertion of implant22into an intervertebral space, as discussed herein. In some embodiments, surface102may be rough, textured, porous, semi-porous, dimpled, knurled, toothed, grooved and/or polished to facilitate engagement with tissue. In some embodiments, surface102and/or surface104may be disposed at alternate orientations, relative to axis X3, such as, for example, transverse, perpendicular and/or other angular orientations such as acute or obtuse, co-axial and/or may be offset or staggered.

End98includes spaced apart flanges106,108extending from surface104. A pin110extends through flange106and into chassis24and a pin112extends through flange108and into chassis24to couple plate96to chassis24such that plate96is pivotable relative to chassis24about pins110,112. Pin110is coaxial with pin112such that pins110,112define a pivot axis that extends perpendicular to axes X1, X3.

End100includes spaced apart extensions114,116extending from surface104. Extension114includes a slot118and extension116includes a slot120. A spur122is positioned between extension114and extension116such that opposite outer surfaces of spur122directly engage inner surfaces of extensions114,116. One or more pins, such as, for example, a pin124extends through slots118,120and spur122such that spur122is pivotable and/or rotatable relative to plate96about pin124. In some embodiments, slots118,120are elongated to allow pin124to translate within slots118,120such that pin124moves between first ends of slots118,120and opposite second ends of slots118,120as implant22moves between the collapsed or unexpanded orientation and the expanded orientation, as discussed herein. In some embodiments, slots118,120extend parallel to axis X3. In some embodiments, slots118,120may be disposed at alternate orientations, relative to axis X3, such as, for example, transverse, perpendicular and/or other angular orientations such as acute or obtuse, and/or may be offset or staggered. Spur122includes a gear126having a plurality of teeth128configured to engage rack94as rack94translates relative to chassis24along axis X1to move implant22between the unexpanded and expanded orientations, as discussed herein.

Rack94is movably coupled to chassis24and spurs86,122such that rack94translates relative to chassis24along axis X1to pivot spur86relative to plate60and pivot spur122relative to plate96to move implant22between the unexpanded and expanded orientations. Rack94includes a body130and spaced apart legs132,134that extend outwardly from body130. Body130defines a cavity136configured for disposal of a component of implant22, as discussed herein. A top surface138of rack94defines a plurality of teeth140that extend along the entire lengths of legs132,134. Teeth140are configured to engage teeth92as implant22moves between the unexpanded and expanded orientations. An opposite bottom surface142of rack94defines a plurality of teeth144that extend along the entire lengths of legs132,134. Teeth144are configured to engage teeth128as implant22moves between the unexpanded and expanded orientations. Surface138extends non-parallel, such as, for example, at an acute angle relative to surface142to provide rack94with a wedge-shape. That is, an end146of rack94has a height that is greater than an opposite end148of rack94. In some embodiments, rack94is continuously tapered from end146to end148. In some embodiments, rack94is progressively tapered from end146to end148

Implant22includes a drive screw, such as, for example an actuator162including an end164and an opposite end166. End164includes a mating part, such as, for example, a male thread168that engages thread50such that actuator162is coaxial with axis X1and rotation of actuator162relative to chassis24and plates60,96in a first rotational direction, such as, for example, clockwise, translates rack94relative to chassis24and plates60,96along axis X1in the direction shown by arrow A inFIG. 2such that teeth92engage teeth140to pivot spur86relative to plate60in the direction shown by arrow B inFIG. 2to move plate60relative to axis X1in the direction shown by arrow C inFIG. 2and teeth128engage teeth144to pivot spur122relative to plate96in the direction shown by arrow D inFIG. 2to move plate96relative to axis X1in the direction shown by arrow E inFIG. 2to move implant22from the collapsed or unexpanded orientation, shown inFIG. 1, to the expanded orientation, shown inFIG. 3. Rotation of actuator162relative to chassis24and plates60,96in an opposite second rotational direction, such as, for example, clockwise, translates rack94relative to chassis24and plates60,96along axis X1in the direction shown by arrow F inFIG. 2such that teeth92engage teeth140to pivot spur86relative to plate60in the direction shown by arrow D inFIG. 2to move plate60relative to axis X1in the direction shown by arrow E inFIG. 2and teeth128engage teeth144to pivot spur122relative to plate96in the direction shown by arrow B inFIG. 2to move plate96relative to axis X1in the direction shown by arrow C inFIG. 2to move implant22from the expanded orientation, shown inFIG. 3, to the collapsed or unexpanded orientation, shown inFIG. 3.

End166includes a drive, such as, for example, a bit170configured for disposal in a socket of a driver to rotate actuator162relative to chassis24and plates60,96. In some embodiments, bit170includes a hexalobe cross-sectional configuration configured for disposal in a socket having a hexalobe cross-sectional configuration. However, it is envisioned that bit170may include a square, triangular, polygonal, star cross sectional configuration configured engage a correspondingly shaped socket of a driver. End166directly engages rack94for disposal of end116in cavity136to couple actuator162to rack94such that actuator162is rotatable relative to rack94and translation of actuator162relative to chassis24and plates60,96along axis X1also translates rack94relative to chassis24and plates60,96along axis X1. In some embodiments, end166can be variously connected with rack94, such as, for example, frictional engagement, threaded engagement, mutual grooves, screws, adhesive, nails, barbs, raised elements, spikes, clips, snaps, friction fittings, compressive fittings, expanding rivets, staples, fixation plates, key/keyslot, tongue in groove, dovetail, magnetic connection and/or posts.

In some embodiments, one or more springs could be included between the endplates and the chassis for biasing the implant in the closed position and/or to allow for driving of the implant closed upon collapse. Springs could also be provided between the spur gears and the chassis, biasing them towards the centerline.

In some embodiments, implant22includes a pin176extending through gear90and chassis24and a pin178extending through gear126and chassis24. Gear90is pivotable and/or rotatable relative to chassis24about pin176such that pin176defines an offset pivot and gear126is pivotable and/or rotatable relative to chassis24about pin178such that pin178defines an offset pivot. In some embodiments, gear90pivots relative to chassis24about pin176and gear126pivots relative to chassis24about pin178as implant22moves between the collapsed or unexpanded orientation, shown inFIG. 1, and the expanded orientation, shown inFIG. 3. In some embodiments, the mechanical advantage of implant22is driven by the offset pivots defined by pins176,178, and/or the pivots defined by pins88,120. The distance between pin88and pin176and between pin120and pin178can be made larger for less mechanical advantage but more expansion, or shorter to get greater advantage. In some embodiments, pin176extends through an elongated slot180in chassis24and pin178extends through an elongated slot182in chassis24, as shown inFIG. 4. Slots180,182each extend perpendicular to axis X1. In some embodiments, pin176translates between opposite ends of slot180and pin178translates between opposite ends of slot182as implant22moves between the collapsed or unexpanded orientation, shown inFIG. 1, and the expanded orientation, shown inFIG. 3. In some embodiments, slot180and/or slot182may be variously shaped, such as, for example, circular, oval, oblong, triangular, square, polygonal, irregular, uniform, non-uniform, offset, staggered, undulating, arcuate, variable and/or tapered. In some embodiments, slot180and/or slot182may be disposed at alternate orientations, relative to axis X1, such as, for example, transverse, perpendicular and/or other angular orientations such as acute or obtuse, co-axial and/or may be offset or staggered.

Implant22has a maximum height H1when implant22is in the collapsed or unexpanded orientation shown inFIG. 1, wherein the maximum height of implant22is defined by the distance between surface66and surface102. Implant22has a maximum height H2when implant22is in the expanded orientation shown inFIG. 3, height H2being greater than height H1. As implant22moves between the collapsed or unexpanded orientation shown inFIG. 1and the expanded orientation shown inFIG. 2, implant22has a maximum height H3that is greater than height H1and less than height H2, as shown inFIG. 2. In some embodiments, pin88translates within slots82,84and pin124translates within slots118,120as implant22moves between the collapsed or unexpanded orientation shown inFIG. 1and the expanded orientation shown inFIG. 3.

In some embodiments, axes X2, X3each extend parallel to axis X1when implant22is in the collapsed or unexpanded orientation shown inFIG. 1and axes X2, X3each extend at an acute angle relative to axis X1when implant122is in the expanded orientation shown inFIG. 3. In some embodiments, axes X2, X3each extend an acute angle relative to axis X1as implant22moves between the collapsed or unexpanded orientation shown inFIG. 1and the expanded orientation shown in FIG.3. In some embodiments, section54directly engages surface68and section58directly engages surface104when implant22is in the collapsed or unexpanded orientation shown inFIG. 1. In some embodiments, section54extends parallel to axes X1, X2and section58extends parallel to axes X1, X3when implant22is in the collapsed or unexpanded orientation shown inFIG. 1. In some embodiments, section44slides along a planar top surface172of body130and section46slides along a planar bottom surface174of body130as implant22moves between the collapsed or unexpanded orientation shown inFIG. 1and the expanded orientation shown inFIG. 3. In some embodiments, surfaces172,174each extend parallel to axis X1.

In assembly, operation and use, spinal implant system20, similar to the systems and methods described herein, and including implant22is employed with a surgical procedure, such as, for example, a lumbar corpectomy for treatment of a spine of a patient including vertebrae. Spinal implant system20may also be employed with other surgical procedures, such as, for example, discectomy, laminectomy, fusion, laminotomy, laminectomy, nerve root retraction, foramenotomy, facetectomy, decompression, spinal nucleus or disc replacement and bone graft and implantable prosthetics including vertebral replacement devices, interbody devices, plates, rods, and bone engaging fasteners for securement of the components of implant22.

Spinal implant system20is employed with a lumbar corpectomy including surgical arthrodesis, such as, for example, fusion to immobilize a joint for treatment of an applicable condition or injury of an affected section of a spinal column and adjacent areas within a body. In some embodiments, implant22is configured for insertion within a vertebral space to space apart articular joint surfaces, provide support and maximize stabilization of vertebrae.

In use, to treat the affected section of vertebrae, a medical practitioner obtains access to a surgical site including vertebrae in any appropriate manner, such as through incision and retraction of tissues. In some embodiments, spinal implant system20may be used in any existing surgical method or technique including open surgery, mini-open surgery, minimally invasive surgery and percutaneous surgical implantation, whereby vertebrae are accessed through a mini-incision, or sleeve that provides a protected passageway to the area. Once access to the surgical site is obtained, corpectomy is performed for treating the spine disorder. The diseased and/or damaged portion of vertebrae, and diseased and/or damaged intervertebral discs are removed to create a vertebral space.

A preparation instrument is employed to remove disc tissue, fluids, adjacent tissues and/or bone, and scrape and/or remove tissue from a vertebral surface of a superior vertebra and/or a vertebral surface of an inferior vertebra. Implant22may be provided with at least one agent, similar to those described herein, to promote new bone growth and fusion to treat the affected section of vertebrae. The components of spinal implant system20may be completely or partially revised, removed or replaced. In some embodiments, implant22is employed to stabilize vertebrae as a pre-assembled device or can be assembled in situ.

Implant22is inserted into a vertebral space via a posterior approach, with implant22in the collapsed or unexpanded orientation shown inFIG. 1. A driver is coupled to bit170by inserting bit170into a socket of the driver. The driver rotates actuator162to move implant22from the collapsed or unexpanded orientation, shown inFIG. 1, to the expanded orientation, as shown inFIG. 3.

In some embodiments, implant22may be moved from the collapse or unexpanded orientation to the expanded orientation until surface66directly engages an end plate of a superior vertebra and surface102directly engages an end plate of an inferior vertebra. In some embodiments, a material, such as, for example, bone graft material is inserted through into implant22.

In some embodiments, implant22may include fastening elements, which may include locking structure, configured for fixation with vertebrae to secure joint surfaces and provide complementary stabilization and immobilization to a vertebral region. In some embodiments, locking structure may include fastening elements such as, for example, rods, plates, clips, hooks, adhesives and/or flanges. In some embodiments, spinal implant system20can be used with screws to enhance fixation. In some embodiments, spinal implant system20and any screws and attachments may be coated with an agent, similar to those described herein, for enhanced bony fixation to a treated area. The components of spinal implant system20can be made of radiolucent materials such as polymers. Radiomarkers may be included for identification under x-ray, fluoroscopy, CT or other imaging techniques.

In some embodiments, the height of implant22may be decreased by coupling the driver to implant22, as discussed herein, and rotating the driver to move implant22from the expanded orientation, shown inFIG. 3, to the collapsed or unexpanded orientation, shown inFIG. 1.

In some embodiments, the use of microsurgical and image guided technologies may be employed to access, view and repair spinal deterioration or damage, with the aid of spinal implant system20. Upon completion of the procedure, the non-implanted components, surgical instruments and assemblies of spinal implant system20are removed and the incision is closed.