CENTRALLY DRIVEN EXPANDABLE IMPLANT AND METHOD
Embodiments of the invention include expandable, implantable devices and methods. Devices expand linearly to provide secure fixation between or among anatomical structures. In some embodiments, an implant replaces one or more vertebral bodies of the spine.
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The present invention relates generally to the field of replacing portions of the human structural anatomy with medical implants, and more particularly relates to an expandable implant and method for replacing skeletal structures such as one or more vertebrae or long bones.
BACKGROUNDIt is sometimes necessary to remove one or more vertebrae, or a portion of the vertebrae, from the human spine in response to various pathologies. For example, one or more of the vertebrae may become damaged as a result of tumor growth, or may become damaged by a traumatic or other event. Removal, or excision, of a vertebra may be referred to as a vertebrectomy. Excision of a generally anterior portion, or vertebral body, of the vertebra may be referred to as a corpectomy. An implant is usually placed between the remaining vertebrae to provide structural support for the spine as a part of a corpectomy.
Many implants are known in the art for use in a corpectomy procedure. One class of implants is sized to directly replace the vertebra or vertebrae that are being replaced. Another class of implants is inserted into the body in a collapsed state and then expanded once properly positioned. Expandable implants may be advantageous because they allow for a smaller incision when properly positioning an implant. Additionally, expandable implants may assist with restoring proper loading to the anatomy and achieving more secure fixation of the implant. Implants that included insertion and expansion mechanisms that are narrowly configured may also provide clinical advantages. In some circumstances, it is desirable to have vertebral endplate contacting surfaces that effectively spread loading across the vertebral endplates. Effective implants should also include a mechanism for securely locking in desired positions, and in some situations, being capable of collapsing. Fusion implants with an uninterrupted opening between their ends may also be advantageous because they allow for vascularization and bone growth through the entire implant.
Expandable implants may also be useful in replacing long bones or portions of appendages such as the legs and arms, or a rib or other bone that is generally longer than it is wide. Examples include, but are not limited to, a femur, tibia, fibula, humerus, radius, ulna, phalanges, clavicle, and any of the ribs.
SUMMARYOne embodiment of the invention is an expandable medical implant for supporting skeletal structures. The implant includes a first tubular member with a connection end and an opposite skeletal interface end, and a second tubular member with a connection end configured to engage with the connection end of the first tubular member, the second tubular member having an opposite skeletal interface end. A key pin is fixed to the first tubular member and positioned in a slot in the second tubular member so that the key pin guides translation between the first tubular member and the second tubular member.
An embodiment of the invention is an expandable medical implant for supporting skeletal structures having a first tubular member with a connection end and an opposite skeletal interface end, and a second tubular member with a connection end configured to engage with the connection end of the first tubular member, the second tubular member having an opposite skeletal interface end. The second tubular member intermittently locks relative to the first tubular member as the implant is expanded. In use in some embodiments, the implant includes an insertion instrument for translating the first tubular member relative to the second tubular member. The insertion instrument has a first tip for attaching to the skeletal interface end of the first tubular member, a second tip for attaching to the skeletal interface end of the second tubular member, and a spreader mechanism for translating the first tip away from the second tip. Moving the first tip toward the second tip results in the first tubular member being released relative to the second tubular member to permit the expandable medical implant to be reduced in length.
Another embodiment of the invention is an end member for a medical implant having a length. The end member is configured to interface with a skeletal structure at the end of the medical implant's length. In some embodiments, the end member includes an end cap with a thickness that provides connection to the medical implant and connection to the skeletal structure, and a shoe for attachment to the end cap. The shoe spans at least a portion of an opening through the end cap, and provides at least in part an interface with the skeletal structure.
An additional embodiment of the invention is a method of placing a medical implant between skeletal structures with an insertion instrument. The method includes accessing a surgical site and expanding the medical implant to fit in a space between skeletal structures by moving at least a portion of the insertion instrument in a first direction. The medical implant progressively locks as expanded. If the locked implant needs to be released from the locked position, the locked implant is released by moving the portion of the insertion instrument in a generally opposite direction.
Yet another embodiment of the invention is an expandable device for supporting skeletal structures. The embodiment includes an implant means for expanding into a space between skeletal structures in a progressively locked state, and an instrument means for expanding the implant into the space by movement of at least a portion of the instrument in a first direction. Movement of the at least a portion of the instrument in a generally opposite direction releases the locked state of the implant.
Another embodiment of the invention is an expandable medical implant for supporting skeletal structures, the medical implant having a length along its expandable dimension. The implant embodiment includes a first tubular member with a connection end, an opposite skeletal interface end, and a central expansion instrument opening. The implant embodiment also includes a second tubular member with a connection end configured to engage with the connection end of the first tubular member. The second tubular member has an opposite skeletal interface end. Embodiments of the invention include an expansion instrument insertable through the central expansion instrument opening and expandable against the first tubular member and the second tubular member to expand the medical implant. The combined first and second tubular members are of a greater dimension along the length of the implant than the combined first and second tubular members are in any dimension perpendicular to their length.
An embodiment of the invention is a method of placing an expandable vertebral body replacement device that includes making an incision adjacent to a vertebral body, removing at least a portion of the vertebral body, and placing an expandable vertebral body replacement device on an insertion end of a contracted expansion instrument. The contracted expansion instrument is configured to pass through a central portion of the expandable vertebral body replacement device without extending onto any surface of the expandable vertebral body replacement device that is lateral to an insertion direction. The method embodiment also includes inserting the vertebral body replacement device at least in part into a volume left open after removal of the portion of the vertebral body, expanding the expansion instrument to secure the vertebral body replacement device, and removing the expansion instrument through the incision.
Another embodiment of the invention is a device for supporting skeletal structures having an expandable implant with a first tubular member and a second tubular member and having a means for receiving an expansion instrument, and an expansion instrument means for expanding against the first tubular member and the second tubular member to expand the medical implant. The expansion instrument means is centrally located on the expandable implant such that when the expandable implant is placed in a person to support the skeletal structures with the expansion instrument means attached, ends and lateral extents of the expandable implant are viewable from the direction of insertion of the implant.
An embodiment of the invention is an expandable medical implant with a length along its expandable dimension. The medical implant is for supporting skeletal structures. The implant includes a first tubular member with a connection end having a first set of protrusions and an opposite skeletal interface end. The implant embodiment includes a second tubular member with a connection end including a second set of protrusions configured to engage with the connection end of the first tubular member, the second tubular member including an opposite end opposite from the connection end. The first set of protrusions includes a flank with a negative flank angle. The flank is positively loaded when the implant is compressively loaded along its length.
Another embodiment of the invention is an expandable medical implant with a length along its expandable dimension. The medical implant is for supporting skeletal structures and includes a first tubular member with a connection end having a first set of protrusions and an opposite skeletal interface end. The implant also includes a second tubular member with a connection end having a second set of protrusions configured to engage with the connection end of the first tubular member. The second tubular member has an opposite end opposite from the connection end. Compressively loading the implant along its length generates a compressive force between the first and second tubular member transverse to the length of the implant. This force tends to more securely engage the first and second sets of protrusions.
Yet another embodiment of the invention is an expandable medical implant with a length along its expandable dimension, the medical implant for supporting skeletal structures. The embodiment of the implant includes a first tubular member with a connection means, a second tubular member with a connections means for coupling with the first tubular member, means for translating the first tubular member relative to the second tubular member to provide coarse expansion adjustment, and means for providing fine length adjustment by turning the second tubular member relative to the first tubular member.
Still another embodiment of the invention is a method of implanting an expandable medical implant with a length along the expandable dimension of the implant. The method embodiment includes the acts of pulling a first tubular member with a first set of threads away from a second tubular member with a second set of threads, causing the first and second sets of threads to translate relative to one another along the length of the implant, and turning the second tubular member relative to the first tubular member to adjust the expanded length of the medical implant.
An embodiment of the invention is a method of implanting an expandable medical implant with a length along the expandable dimension of the implant. The embodiment includes the act of pulling a first tubular member with a first set of right-hand threads away from a third tubular member with a fourth set of left-hand threads. The medical implant comprising a second tubular member with a second set of right-hand threads and a third set of left-hand threads, the act of pulling causing the first and second sets of threads to translate relative to one another along the length of the implant and the third and fourth sets of threads to translate relative to one another along the length of the implant. An additional act of the embodiment is turning the second tubular member relative to the first and third tubular members to adjust the expanded length of the medical implant.
The term tubular as used herein includes generally cylindrical members as are illustrated in
The illustrated key pin 13 guides the translation of the first and second tubular members 10, 20 and provides torsional stability between the tubular members 10, 20. In addition, as shown in
As shown in the illustrated embodiment, the first tubular member 10 fits within the second tubular member 20. However, in other embodiments, the first tubular member may be of greater diameter than the second tubular member with the connection between the two members being reversed in orientation. Alternatively, the first and second tubular members may be of approximately the same size, but have legs that exist coplanarly or within the same tubular geometry with the legs of the other.
As shown in
As best illustrated in
The first set of teeth 15 interdigitate with every other one of the teeth of the set of second teeth 25. This or other varied spacings may be advantageous. As noted above, the force required to expand the implant is proportional to the number of sets of teeth that are in contact while the tubular members 10, 20 are being translated. However, if teeth on both tubular members 10, 20 are spaced apart at greater distances, the number of increments to which the implant may be adjusted is decreased. By maintaining the frequency of the rows of the first set of teeth 15 and increasing frequency of the second set of teeth 25, the force required to expand the implant is reduced, but the number of discrete points of adjustment is not reduced. In some embodiments, the increased frequency of teeth could be maintained on the second tubular member 20 while the spacing is increased on the first tubular member 10.
Referring now to
When the drive handle 57 is rotated in a clockwise direction, the inner shaft 53 actuates the rack and pinion assembly, spreading the first and second tips 81, 82, and expanding the implant 1. Other embodiments of the insertion instrument 50 may operate by motions other than turning of a handle or knob, or may expand as a result of counter-clockwise rotation. For example and without limitation, the spreading motion may be created by a linkage system such as pliers, by a ratcheting or screw-driven jack, by pull or push grip handles, or by pneumatic or electric actuators. The alternative mechanisms may be reversible or two separate instruments may be used to expand and compress the tips of the instrument. Instruments such as those disclosed in U.S. patent application Ser. No. 10/441,689, entitled “Instruments and Techniques for Separating Bony Structures,” filed May 20, 2003; and U.S. patent application Ser. No. 11/291,419, entitled “End Device for a Vertebral Implant,” filed Dec. 1, 2005 may be used in embodiments of the invention and these applications are hereby incorporated by reference in their entirety. In some embodiments, the rack and pinion assembly 60 is offset laterally from the outer shaft to provide direct visualization of the implant in the surgical site. Instruments of any of these varieties may be used as part of or in combination with implants 1, 1a, 100, and 200, specifically disclosed herein or as otherwise effectively applied.
The implant 1 of the illustrated embodiment progressively locks as expanded. The expansion may also be described as intermittent since locking occurs at the discrete locations where teeth from the first and second sets of protrusions align.
In addition to releasing locking, the capture mechanism 83 enables a secure temporary connection to the implant 1 by the insertion instrument 50. With the implant 1 held in the insertion instrument 50, the implant 1 may be positioned, re-positioned, or removed from the surgical site. In other embodiments, a capture mechanism may be a feature of the first tip 81. In such embodiments, release of the locking may be keyed to force or motion from an action delivered through the first tip 81.
The insertion instrument 50 in combination with the first and second tubular members 10, 20 provides a significant clinical advantage in some embodiments. The combination enables insertion, expansion, locking, and contraction without the need for exchanging instruments or adding additional pieces to the device. The illustrated implant 1 automatically locks as expanded. The insertion instrument 50 is capable of holding, expanding, contracting, and repositioning the implant 1 without ever being removed from the surgical site.
Generally stated, the insertion instrument 50 in combination with the implant 1 is an expandable skeletal structure support device that progressively locks as expanded. Movement of at least a portion of the instrument in a first direction generates the expansion, and generally opposite movement releases the locked state of the implant 1.
In practice, an implant such as the implant 1 is placed between skeletal structures by first accessing the surgical site. Access may be through any surgical approach that will allow adequate visualization and/or manipulation of the skeletal structures. Example surgical approaches include, but are not limited to, any one or combination of anterior, antero-lateral, posterior, postero-lateral, transforaminal, and/or far lateral approaches. Implant insertion can occur through a single pathway or through multiple pathways, or through multiple pathways to multiple levels of the spinal column. Minimally invasive techniques employing instruments and implants are also contemplated. Similar approaches and pathway are applicable to implants 100 and 200.
With access established, the medical implant 1 is placed and expanded to fit in a space between skeletal structures. It is often necessary to further open or prepare the space between skeletal structures, which can be done by any technique available to the surgeon. Expansion of the implant 1 may be carried out by moving at least a portion of the insertion instrument 50 in a first direction, as detailed herein. Embodiments of the implant 1 progressively lock as expanded by the insertion instrument 50. In some circumstances, it is desirable to release the implant 1 from its locked state. For example, upon initial placement and assessment under fluoroscopy, a determination may be made that the implant 1 is not appropriately placed or sized. As described in detail in association with
Each distal component 150b includes a distal outer torque shaft 151b and a distal inner torque shaft 153b. The distal inner torque shaft 153b has a distal inner torque coupling 152b and a retaining notch 154. The distal inner torque coupling 152b fits in a corresponding proximal inner torque coupling (not shown) to transfer torque from the proximal inner torque shaft 153a to the distal inner torque shaft 153b. The retaining notch 154 is configured to receive one or more detent balls 156 to restrict movement of the distal component 150b away from the proximal component 150a. The proximal outer torque shaft 151a and the distal outer torque shaft 151b also couple through a torque fitting. A coupling sleeve 152 is disposed over the outer torque shafts 151a, 151b to maintain their alignment and to keep the detent balls 156 engaged in the retaining notch 154. The coupling sleeve 152 is maintained in a predetermined range by attachment to retaining pin 158. A retaining spring 159 keeps the coupling sleeve 152 biased over the joint between the outer torque shafts 151a, 151b.
In operation, to load a distal component 150b into the proximal component 150a, the coupling sleeve 152 is pulled proximally, and the distal component 150b is inserted into the proximal component 150a. The coupling sleeve is allowed to slide over the joint between the components, and the instrument is ready for use. To remove the distal component 150b, the coupling sleeve 152 is pulled proximally and the distal component 150b is removed from the proximal component. Similarly, various distal components with differently sized implants may be coupled to the proximal component 150a.
The end cap 30 may be a separate component, as illustrated, or may be integrated with an implant such as the medical implant 1a. The end member 4 in total and the end cap 30 may be of a uniform thickness, as shown in
As shown in
The end cap 30 shown includes cap connectors 42 for coupling the end cap 30 to the medical implant 1a. The cap connectors 42 shown are round pins, but in other embodiments could be other shapes and could include other functions. For example, the cap connectors 42 may be square in cross-section or any other geometric shape. The cap connectors 42 may be oblong for sliding in slots into which they could be engaged, or may have hooked ends to grasp or otherwise capture a portion of the medical implant 1a when coupled. The implant 1a of
As illustrated in
In some embodiments, the superior and inferior shoes, 40, 41 may be made at least in part from a bioresorbable material. A bioresorbable material provides initial support and an initial containment structure for grafting material that may be placed within the implant. However, over time, the material dissolves and/or the body removes and replaces the material with tissue structures such as bone, thereby providing an especially open pathway through the implant for tissue growth. Examples of bioresorbable materials that could be incorporated in the superior and inferior shoes 40, 41, include but are not limited to allograft, autograft, and xenograft bone materials, polylactide, polyglycolide, tyrosine-derived polycarbonate, polyanhydride, polyorthoester, polyphosphazene, calcium phosphate, hydroxyapatite, bioactive glass, and combinations thereof.
In other embodiments, the superior and inferior shoes 40, 41 may be at least in part a bioactive substance proportioned to provide a clinical benefit to the recipient of the implant. Bioactive substances include but are not limited to antibiotics or other substances that affect infection, bone growth and bone ingrowth promoting substances, substances that treat or attack cancer cells, or any other substance that makes a therapeutic contribution.
The superior and inferior shoes 40, 41 include shoe connectors 47 for coupling the shoes 40, 41 to the end caps 30, 30a. The shoe connectors 47 shown are round pins, but in other embodiments could be other shapes and could include other functions. For example, the shoe connectors 47 may be square in cross-section or any other geometric shape. The shoe connectors 47 may be oblong for sliding in slots into which they could be engaged, or may have hooked ends to grasp or otherwise capture a portion of the end caps 30, 30a when coupled. The end caps 30, 30a may include sliced openings similar to those described in association with the sliced openings 43 described above. In addition, or in the alternative, the shoe connectors 47 may include relief cuts through some or all of their cross-section to provide a living hinge or spring effect when inserted into an appropriately sized opening.
The expandable medical implant 100 shown also includes a second tubular member 120 with a connection end 121 configured to engage with the connection end 111 of the first tubular member 110 by fitting within the second tubular member 120. In other embodiments, the first and second tubular members 110, 120 may partially interdigitate or may have a side-by-side alignment, or other configuration. The second tubular member 120 has an opposite second skeletal interface end 122. The embodiment shown includes a bone growth packing aperture 105 through which bone growth material may be packed and through which bone growth may occur. Additionally, the bone growth packing aperture 105 is an aid in radiographic assessment when the expandable medical implant 100 is made from a material that is not radiolucent. Lateral openings 106 may be useful for packing of bone growth material, and provide channels through which bone growth and radiographic assessment may occur.
The term tubular as used herein includes generally cylindrical members as are illustrated in
As illustrated in
Embodiments of the invention may also include an expansion instrument insertable through the central expansion instrument opening 114. The insertion end 140 of such an expansion instrument is illustrated in
As shown in
In other embodiments, a relief cut in the second tubular member 120 and a continuous shape in the first tubular member 110 could cause flexing of the second tubular member 120 rather than the first tubular member 110. Similarly, the degree and direction of flexing can be controlled by the use of different materials, various degrees of relief cutting, different cross-sectional shapes, and the shapes of the teeth or protrusions employed, among other factors. The force required for various degrees of flexing of the members is also proportional to the force required to expand the implant. Therefore, the force required to expand the implant may be maintained within a desirable range by controlling the factors detailed above.
As best illustrated in
The first set of teeth 115 interdigitate with every other one of the teeth of the set of second teeth 125. This or other varied spacings may be advantageous. As noted above, the force required to expand the implant is proportional to the number of sets of teeth that are in contact while the tubular members 110, 120 are being translated. However, if teeth on both tubular members are spaced apart at greater distances, the number of increments to which the implant may be adjusted is decreased. By maintaining the frequency of the rows of the first set of teeth 115 and increasing frequency of the second set of teeth 125, the force required to expand the implant is reduced, but the number of discrete points of adjustment is not reduced. In some embodiments, the increased frequency of teeth could be maintained on the second tubular member 120 while the spacing is increased on the first tubular member 110.
In some embodiments, the second tubular member 120 includes an instrument aperture 130 for receiving at least a portion of the expansion instrument insertion end 140. Such an instrument aperture may provide for stability between the expansion instrument insertion end 140 and the expandable medical implant 100 and may provide for additional space through which to place the insertion end 140, among other purposes.
As illustrated in
In some embodiments, the expandable medical implant may also include a bone growth promoting substance. The use of such substances is described in more detail below.
Some embodiments associated with implant 1, 1a, 100, and 200 may also include supplemental fixation devices as part of the expandable medical implant for further stabilizing the anatomy. For example, and without limitation, rod and screw fixation systems, anterior or lateral plating systems, facet stabilization systems, spinal process stabilization systems, and any devices that supplement stabilization may be used as a part of the expandable medical implant.
Embodiments of the invention are generally for supporting skeletal structures, and may include an expandable implant with a first tubular member and a second tubular member. The expandable implant of some embodiments includes a means for receiving an expansion instrument. The means for receiving an expansion instrument may be an aperture or apertures of any type, may be a protrusion or protrusions of any type, may include a friction interface, or any other mechanism designed to transfer force from the expansion instrument to the implant. The expansion instrument means is for expanding against the first tubular member and the second tubular member to expand the implant. The instrument means may include device sufficient to separate the first and second tubular members.
The expansion instrument means of some embodiments is centrally located on the expandable implant such that when the expandable implant is placed in a person to support the skeletal structures with the expansion instrument means attached. Ends of the expandable implant that interface with the skeletal structure may be viewed from the direction of insertion of the expandable implant. In some of these and other embodiments, lateral extents of the expandable implant are also viewable from the direction of insertion of the expandable implant. The term lateral extents is intended to include segments of the expandable implant such as lateral openings 106 that are located on or near edges of the expandable implant that are transverse to the insertion direction of the implant.
An embodiment of the invention is a method of placing an expandable vertebral body replacement device such as expandable medical implant 100 shown in
As shown in
Embodiments of the method may further include inserting the expandable medical implant 100 at least in part into a volume left open after removal of the portion of the vertebral body, expanding the expansion instrument to secure the expandable medical implant 100, and removing the expansion instrument through the incision. Some embodiments may also include placing bone growth promoting substance within the expandable medical implant 100 prior to expansion of the expandable medical implant 100. Further, in some embodiments, bone growth promoting substance may additionally or lieu be placed within the expandable medical implant 100 after expansion of the expandable medical implant 100.
Additional fixation devices to supplement the fixation of the vertebral body replacement may be added to the construct in some circumstances. Suitable supplemental fixation devices are described herein and include others that provide a clinical benefit.
As shown in
The term “flank” as used herein is the thread face, excluding any crest or root of the thread profile. The term “flank angle” as used herein is the angle between the individual flank and a perpendicular 241 to the axis of the thread measured in the axial plane. As shown, the axis of the thread is parallel with the length of the expandable implant 200. As an example, the sets of protrusions will be described as a thread embodiment, but the protrusions in other embodiments may be notches or ratchetings of any operable type.
As seen with reference to
In a device such as expandable implant 200, maintenance of the implant height under compressive load requires that the protrusions of the tubular members stay engaged with one another. The negative flank angle protrusions illustrated in
Embodiments of the invention as described in relation to
The term tubular as used herein includes generally cylindrical members as are illustrated in
In alternate embodiments, the opposite end 222 may be configured to be a skeletal interface end, rather than connecting to a third tubular member.
As shown in
As described above with regard to the protrusions of
The implant
Embodiments of the invention include an insertion instrument with a lower tip 281 and an upper tip 282, as illustrated in
An embodiment of the invention is an expandable medical implant 200 with a length along its expandable dimension, the medical implant 200 for supporting skeletal structures. The embodiment includes a first tubular member 210 with a connection means and a second tubular member 220 with a connections means for coupling with the first tubular member. A means for translating the first tubular member 210 relative to the second tubular member 220 to provide coarse expansion adjustment is provided along with a means for providing fine length adjustment by turning the second tubular member 220 relative to the first tubular member 210. As illustrate in
An embodiment of the invention is a method of implanting an implant, such as expandable medical implant 200. The expandable medical implant 200 has a length along the expandable dimension of the implant. The method may include pulling a first tubular member 210 with a first set of protrusions 215, or in some embodiments, threads, away from a second tubular member 220 with a second set of protrusions 225, or in some embodiments threads, causing the first and second sets of protrusions 215, 225 to translate relative to one another along the length of the implant. Further, in some embodiments, turning the second tubular member 220 relative to the first tubular member 210 adjusts the length of the expandable medical implant 200.
Another method embodiment is also directed to implanting an expandable medical implant with a length along the expandable dimension of the implant. An implant such as expandable medical implant 200 may be expanded by pulling a first tubular member 210 with a first set of protrusion 215 away from a third tubular member 230 with a fourth set of protrusions 235. In this embodiment, the first set of protrusions 215 is a set of right-hand threads and the fourth set of protrusions 235 is a set of left-hand threads. The expandable medical implant 200 also includes a second tubular member 220 with a second set of protrusions 225 and a third set of protrusions 227. In this embodiment, the second set of protrusions 225 is a set of right-hand threads and the third set of protrusions 227 is a set of left-hand threads.
The act of pulling noted above may cause the first and second sets of protrusions, 215, 225, or threads, to translate relative to one another along the length of the implant 200. Similarly, the act of pulling may cause the third and fourth sets of protrusions, 227, 235, or threads, to translate relative to one another along the length of the implant 200. In some embodiments, turning the second tubular member 220 relative to the first and third tubular members 210, 230 will adjust the expanded length of the expandable medical implant 200. Turning in a first direction will cause shortening of the expandable medical implant 200, and turning in an essentially opposite direction will cause lengthening of the expandable medical implant 200. For example, turning the second tubular member 220 clockwise shortens the expandable medical implant 200, and turning the second tubular member 220 counter-clockwise lengthens the expandable medical implant 200.
Various method embodiments of the invention are described herein with reference to particular implants 1, 1a, 100, and 200. However, in some circumstances, each disclosed method embodiment may be applicable to each of the implants 1, 1a, 100, and 200, or to some other implant operable as disclosed with regard to the various method embodiments.
In some circumstances, it is advantageous to pack all or a portion of the interior and/or periphery of the implants 1, 1a, 100, 200 with a suitable osteogenic material or therapeutic composition. Osteogenic materials include, without limitation, autograft, allograft, xenograft, demineralized bone, synthetic and natural bone graft substitutes, such as bioceramics and polymers, and osteoinductive factors. A separate carrier to hold materials within the device may also be used. These carriers may include collagen-based carriers, bioceramic materials, such as BIOGLASS®, hydroxyapatite and calcium phosphate compositions. The carrier material may be provided in the form of a sponge, a block, folded sheet, putty, paste, graft material or other suitable form. The osteogenic compositions may include an effective amount of a bone morphogenetic protein (BMP), transforming growth factor β1, insulin-like growth factor, platelet-derived growth factor, fibroblast growth factor, LIM mineralization protein (LMP), and combinations thereof or other therapeutic or infection resistant agents, separately or held within a suitable carrier material. A technique of an embodiment of the invention is to first pack an unexpanded implant, as shown in
Embodiments of the implant in whole or in part may be constructed of biocompatible materials of various types. Examples of implant materials include, but are not limited to, non-reinforced polymers, carbon-reinforced polymer composites, PEEK and PEEK composites, shape-memory alloys, titanium, titanium alloys, cobalt chrome alloys, stainless steel, ceramics and combinations thereof. If the trial instrument or implant is made from radiolucent material, radiographic markers can be located on the trial instrument or implant to provide the ability to monitor and determine radiographically or fluoroscopically the location of the body in the spinal disc space. In some embodiments, the implant or individual components of the implant are constructed of solid sections of bone or other tissues. In other embodiments, the implant is constructed of planks of bone that are assembled into a final configuration. The implant may be constructed of planks of bone that are assembled along horizontal or vertical planes through one or more longitudinal axes of the implant. Tissue materials include, but are not limited to, synthetic or natural autograft, allograft or xenograft, and may be resorbable or non-resorbable in nature. Examples of other tissue materials include, but are not limited to, hard tissues, connective tissues, demineralized bone matrix and combinations thereof. Examples of resorbable materials that may be used include, but are not limited to, polylactide, polyglycolide, tyrosine-derived polycarbonate, polyanhydride, polyorthoester, polyphosphazene, calcium phosphate, hydroxyapatite, bioactive glass, and combinations thereof. Implant may be solid, porous, spongy, perforated, drilled, and/or open.
While embodiments of the invention have been illustrated and described in detail in the disclosure, the disclosure is to be considered as illustrative and not restrictive in character. All changes and modifications that come within the spirit of the invention are to be considered within the scope of the disclosure.
Claims
1-14. (canceled)
15. A method of placing an expandable vertebral body replacement device comprising:
- making an incision adjacent to a vertebral body;
- removing at least a portion of the vertebral body;
- placing an expandable vertebral body replacement device on an insertion end of a contracted expansion instrument, wherein the contracted expansion instrument is configured to pass through a central portion of the expandable vertebral body replacement device without extending onto any surface of the expandable vertebral body replacement device that is lateral to an insertion direction;
- inserting the vertebral body replacement device at least in part into a volume left open after removal of the portion of the vertebral body;
- expanding the expansion instrument to secure the vertebral body replacement device; and
- removing the expansion instrument through the incision.
16. The method of claim 15 further comprising placing bone growth promoting substance within the vertebral body replacement device prior to expansion of the vertebral body replacement device.
17. The method of claim 15 further comprising placing bone growth promoting substance within the vertebral body replacement device after expansion of the vertebral body replacement device.
18. The method of claim 15 further comprising implanting additional fixation devices to supplement the fixation of the vertebral body replacement.
19. (canceled)
20. A system comprising:
- a first tubular member with a connection end, an opposite skeletal interface end, and a central expansion instrument opening;
- a second tubular member with a connection end configured to engage with the connection end of the first tubular member, the second tubular member having an opposite skeletal interface end, the connection end of the second tubular member having an end surface on a distal most portion of the connection end opposite the skeletal interface end of the second tubular member; and
- an expansion instrument insertable through the central expansion instrument opening and expandable against the first tubular member and the end surface of the second tubular member to expand the medical implant.
21. The system of claim 20, wherein the first tubular member includes a relief cut to facilitate portions of the first tubular member flexing away from the second tubular member to permit translation between the first and second tubular members.
22. The system of claim 21, wherein the relief cut includes the central expansion instrument opening.
23. The system of claim 22, wherein there are two relief cuts on opposite sides of the first tubular member through which the expansion instrument is inserted.
24. The system of claim 20, wherein the first tubular member includes a set of adjacent protrusions.
25. The system of claim 24, wherein the second tubular member includes a set of protrusions that are not all adjacent and that interdigitate with one or more of the adjacent protrusions.
26. The system of claim 20, wherein the first and second tubular members are generally cylindrical.
27. The system of claim 20, wherein an insertion end of the expansion instrument has collapsed configuration in which the insertion end has a generally round cross-section and an expanded configuration in which the insertion end has a generally non-round cross-section.
28. A system comprising:
- an expandable implant having: a first tubular member extending along a first axis having a first end portion opposing a second end portion, the first tubular member having a first elongated slot extending along a length of the first tubular member between the first and second end portions and a second elongated slot on an opposing side of the first tubular member from the first elongated a second tubular member movably connected to the first tubular member, the second tubular member having a third end portion opposing a fourth end portion, the third end portion defining a first recess and a second recess on an opposing side of the second tubular member from the first recess, wherein the first and second recessed are respectively aligned with the first and second elongated slots to define a first and second openings for receiving an expansion instrument.
29. The system of claim 28, wherein the first and second openings provide access to a channel extending substantially transverse to the first axis through the first and second tubular members.
30. The system of claim 28, further comprising the expansion instrument insertable through the first opening and expandable against the first and second tubular members to expand the implant along the first axis.
31. The system of claim 30, wherein the expansion instrument is comprised of an upper and lower segment each having a semi-circular cross section.
32. The system of claim 30, wherein the first recess and the first elongated slot each include a rounded engagement surface matching the profile of the upper and lower segments of the expansion instrument.
33. The system of claim 30, wherein the expansion instrument is expandable to move the first tubular member away from the second tubular member to increase an overall height of the implant, and wherein the engagement of the first end portion with the third end portion maintains the overall height of the implant after expansion.
34. The system of claim 28, wherein the first opening increases in length as the expandable instrument expands the implant generally along the first axis.
35. The system of claim 28, wherein the first elongated slot extends in the direction of the first axis along a majority of the length of the first tubular member.
Type: Application
Filed: Dec 16, 2010
Publication Date: Apr 14, 2011
Applicants: Warsaw Orthopedic, Inc. (Warsaw, IN), SDGI Holdings, Inc. (Wilmington, DE)
Inventors: Andrew M. Dickson (Memphis, TN), James S. Harrop (Philadelphia, PA), Dean G. Karahalios (Lake Forest, IL), Eric A. Potts (Indianapolis, IN), Christopher I. Shaffrey (Charlottesville, VA), Jeffrey C. Wang (Sherman Oaks, CA)
Application Number: 12/970,649