Modular intervertebral disc prosthesis with compression elements, implantation methods, and inventory systems

Abstract

In embodiments, each of a plurality of the selected modular nucleus implant segments comprising base portion formed of a rigid material, with at a superior lobe and inferior lobe extending from the interfacing base portion. Each of the superior lobe and inferior lobe comprising a compressible spring component and providing an exterior C-shaped wall surface and having a compressible spring component having voids defined therein. The compressible spring component distinct from the interfacing base portion, and being captured and fixed with respect thereto. When viewed from the side the implant segments have a ovate shape or ovate with truncations on the elongate axis. Means are proved to contract the segments when inserting into a lordotic evacuated nucleus.

Description

Attorney Docket No. 5364.002W01MODULAR INTERVERTEBRAL DISC PROSTHESIS WITH COMPRESSION ELEMENTS, IMPLANTATION METHODS, AND INVENTORY SYSTEMSRELATED CASES

[0001] This application claims priority to U. S. Provisional Application No. 63 / 735,832 filed December 18, 2024, and also claims priority to U. S. Provisional Application No.63 / 874,615 filed September 2, 2025.FIELD OF INVENTION

[0002] The present disclosure relates to nucleus pulpous prostheses that may be inserted and assembled in situ in an evacuated nucleus cavity in an annulus fibrosis of a human spine after removal of the existing nucleus pulposus and providing a customizable prosthesis filling the evacuated cavity in a patient.BACKGROUND

[0003] Efforts have been made in the past 20 plus years for a nucleus prosthesis that could be implanted with minimally invasive surgery, including posterior serial insertion of modular implant segments through a minimally sized posterior access port and in situ assembly of the segments in an evacuated nucleus pulposis space. See for example:7,267,690; 7,591,853 8,038,718; 8,100,977; 9,510,953; 9,737,414; 10,195,048; and11,246,714. All of these patents have overlapping inventorship with the current application and all are incorporated by reference for all purposes. The devices, techniques, and methods described in these prior art references have provided very significant advances over previous alternatives to spinal fusions for surgical treatment of degenerative disc disease.

[0004] Such in situ assemblable prosthesis present significant design challenges with respect to Hie considerable high cyclic loading of the prosthesis, the challenges of in situ assembly through a minimal sized portal, for example 15 mm x 10 mm, including visualization, manipulation, interconnecting implant segments, and assurance of complete connections.

[0005] However, such efforts have not been widely adopted by the medical community, particularly orthopedic surgeons, nor have products incorporating the innovations thereinAttorney Docket No. 5364.002W01been widely approved by regulatory agencies. As described below, the inventors have identified concerns, issues, deficiencies in the prior art, heretobefore not addressed and have addressed same to provide embodiments with enhanced performance over extended periods of time, and that facilitate easier installation and in situ assembly by surgeons.SUMMARY

[0006] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

[0007] The inventors have identified that a minimal invasively implantable nucleus prosthesis providing full motion to the patient over an extended period of time requires optimally integrated components providing not only a highly robust assembly that performs optimally over an extended period of time, that may be customizable for the particular nucleus space, including nucleus spaces in lordotic segment of die spine of a patient, and that also is surgeon friendly, minimizing conventional implantation challenges. Such integration of components includes integration at the implant segment level, as well as interfaces and integration between adjacently joined implant segments, as well as cooperation between the implant segments and implantation tools.

[0008] In embodiments, each of a plurality of the selected modular nucleus implant segments comprising interfacing base portion formed of a rigid material, providing a spring constant of less than with at a superior lobe and inferior lobe extending from the interfacing base portion. Each of the superior lobe and inferior lobe comprising a compressible spring component and providing an exterior C-shaped wall surface, and having a compressible spring component having voids defined therein. The compressible spring component distinct from the interfacing base portion, and being captured and fixed with respect thereto.

[0009] In embodiments, each of a plurality of the selected modular nucleus implant segments comprising interfacing base portion formed of a rigid material, with at least one lobe extending from the interfacing base portion. The at least one lobe having an exterior C-shaped wall surface and having a compressible spring component having voids defined therein. The compressible spring component distinct from the interfacing base portion, and being captured and fixed with respect thereto.Attorney Docket No. 5364.002W01

[0010] The inventors have recognized that prior art does not take into consideration or adequate consideration of the predominance of lordotic spines and that when a nucleus pulposis is evacuated from an annulus fibrosis the superior anterior thickness of the space increases anteriorly. See FIGS. 1A-1D. Additionally, the space typically has, when viewed laterally, concave vertebral plates which are at a minimal distance between each other posterior of the evacuated nucleus space, right where the annulus fibrosis connects and where the access port is created by the surgeon.

[0011] When a surgical channel and a posterior access port is created into the patient, and the nucleus evacuated, the superior anterior gap between the posterior corners may be or is often less than the superior-inferior thickness of the evacuated nucleus space. Such creates issues in trying to insert segments that are reflective of the average superior inferior thickness of the evacuated nucleus space, such segments, typically being completely elastomeric, may squeeze in with difficulty. Conventionally such segments have parallel or symmetric superior surfaces and inferior surfaces such that they do not adequately form fit the evacuated nucleus space. Although surgical removal of portions of the posterior corner of the vertebral plates can allow accommodation of more conforming sized implant segments, such surgery is not preferred and makes the procedure much less invasive. These issues and others are addressed with embodiments described herein, providing solutions with minimally invasive surgery.

[0012] Recognizing the immense variability of size and shape of invertebrate disks, and correspondingly the variability in the size and shape of nucleus pulposis therein, a modular nucleus prosthesis system accommodates different sizes and shapes of evacuated nucleus pulposus spaces including for intervertebral segments that have a lordotic variation in posterior anterior thickness, and provides a plurality of means for facilitating minimally invasive implantation of a mimetic nucleus prosthesis in a patient. The mimetic nucleus prosthesis assemblable in situ in the evacuated nucleus space from a plurality of selected modular nucleus implant segments inserted serially through a posterior minimally sized access port between adjacent vertebral bodies and through the annulus fibrosis. The system and the segments accommodating insertion through an access port in an annulus fibrosis with an access height less than the height of individual segments. When inserted and assembled in situ, the mimetic nucleus prosthesis provides micro-movement of the prosthesis with respect to vertebral plates.

[0013] Recognizing that tire shape of tire evacuated nucleus pulposis cavity in a lordotic disc with views taken at a sagittal plane has an ovate shape, modular segments with aAttorney Docket No. 5364.002W01corresponding shape and having a rigid exterior convex superior surface, a rigid inferior surface and a rigid central base having insertion tool interface and adjacent modular segment interfaces when view laterally, and are provided with means and structure facilitating posterior insertion through a posterior access port and in situ assembly into a mimetic nucleus prosthesis for a patients.

[0014] Recognizing that the bearing surfaces of the superior vertebral plate and the inferior vertebral plate in an evacuated nucleus pulposis cavity in a lordotic disc, with views taken at a sagittal plane, has an truncated elongated egg shape, embodiments of modular segments assemblable in situ have a conforming upper surface and lower surface shape when view laterally. In embodiments such segments have a rigid exterior convex superior surface, a rigid inferior surface and a rigid central base having insertion tool interface and adjacent modular implant segment interfaces when view laterally are provided with means and structure facilitating posterior insertion through a posterior access port and in situ assembly into a mimetic nucleus prosthesis for a patients

[0015] Recognizing that the minimally sized posterior access port to the nucleus pulposus space may be significantly limited by the gap between the adjacent posterior corners of the adjacent vertebral plates, means and capabilities for reducing the superior inferior thickness of the modular segments facilitating implantation are provided by embodiments herein. Additionally, means and capabilities are provided for providing a highly robust prosthesis system for minimizing failures during implantation and for extended use in patients.

[0016] Recognizing that conventional implant segments utilizing a central base portion with an elastomer layer thereover superiorly and inferiorly have delamination issues and concerns, embodiments herein provide structure with interlocking geometry between a rigid base portion and accomplish the interlocking by overmolding the elastomeric material on the base portion and / or on the external superior and / or inferior walls, overmolded elastomeric spring inserts. Such structure providing interdigitation

[0017] Each of a plurality of the selected modular nucleus implant segments comprising a rigid material interfacing base portion, with at least one lobe extending from the base portion. The lobe having an exterior rigid C-shaped wall portion with a smooth exterior surface conformingly shaped to a lordotic evacuated nucleus space and further having a resilient compressible spring insert positioned between the C-shaped wall portion and tire interfacing base. The spring insert may be formed of a rigid material utilizing bending of cantilevered arms for the spring action or may be formed of an elastomeric material captured within theAttorney Docket No. 5364.002W01space between one of the exterior rigid C-shaped wall portions and the interfacing base portion.

[0018] In embodiments, a base unit is formed of a rigid material such as a polymer, for example PEEK, opposing C-shaped exterior wall portions are spaced above and below the base unit and a pair of spring inserts comprising elastomeric material extends between the base unit and each respective C-shaped exterior wall portions. In embodiments, the elastomeric material is secured to each of the base unit and the C-shaped exterior wall portions by connection portions.

[0019] In some examples, the disclosure describes a modular intervertebral disc prosthesis, comprising three or more modular implant segments that may be serially inserted through a minimal surgical channel through the patient’s back, assembled in situ, that are liighly robust providing resistance to breakage during installation, that are amenable installation in a lordotic space, and that provide a liighly secure connection between adjacent modular implant segments.

[0020] In embodiments, tire modular intervertebral nucleus pulposus prosthesis comprises a plurality of interconnected modular implant segments, each segment including an a superior exterior wall, an inferior exterior wall, a base positioned between the superior exterior wall and the inferior external wall, at least one of superior exterior wall and the inferior external wall associated with the base, for example, for placement and positioning. The base having one or two implant segment connecting structures for in situ attachment to an adjacent implant segment. The base having a feature for facilitating insertion of the segment into the evacuated nucleus space through a minimal opening extending into said space through the annulus fibrosis, for example a 12 mm by 12 mm opening. The exterior and inferior walls defining an open interior defined by internal wall surfaces, the exterior walls of the segment being elastically deflectable toward the base under loading. A plurality of fingers positioned within tire open interior, each of the plurality of fingers having an anchored end, having a free end engaging or confronting the interior wall surface, being bendable when the segment is deflected toward the base while slidingly engaging the interior wall surface as the walls is compressed. In embodiments, one or more hard stops may be provided in the open interior limiting the deflection of exterior wall of the segment loop.

[0021] In embodiments, the segment is C-shaped and extends outwardly from opposite sides of the base and loops around with a smooth curvature. When implanted, the lobe of the segment may then have an anteriorly projecting lobe portion and a posteriorly projecting lobeAttorney Docket No. 5364.002W01portion. Such opposing loop portions may effectively absorb compression from flexion or extension of the spine by one loop portion compressing and opposing loop portion expanding.

[0022] A feature and advantage of embodiments, is the utilization of bendable cantilevered arms within a closed spring loop that slidingly engage with the surface of the closed loop wall, such deflection of the arm with a non-attached end engaging and sliding on the wall surface of the loop wall has been observed to minimizes stresses on any specific portion of the closed spring loop. Said minimization of stress reduces fatigue of the segment material and thereby provides for a prosthesis capable of an extreme number of compressions without failure suggesting an extended implant period if not a permanent implantation. The capability of segments formed of PEEK as described herein have been demonstrated to be able to withstand an extreme number of repeti tive compressions without failure.

[0023] In embodiments, a segment for a nucleus prosthesis is formed from two or more components and assembled prior to implantation. For example, a first segment component may comprise a base portion and a unitary spring loop. A second segment component may comprise a spring insert insertable into an open interior in the spring loop of the first component. The first component and second component may be fixed together by mechanical means, by welding, or other known methods. Said assembled segment may then be implanted into the patient with other like assembled segments. The first and second components may be selected to provide particular parameters such as size, compressibility, and configuration.

[0024] In embodiments, the modular intervertebral nucleus pulposus prosthesis comprises a plurality of interconnected modular implant segments, each segment including a superior exterior wall, an inferior exterior wall, a base positioned between die superior exterior wall and the inferior external wall, at least one of superior exterior wall and the inferior external wall being part of a compressible spring extending from the base. The base having one or two adjacent segment interfaces, that is, connecting structures, for in situ attachment to an adjacent segment. The base having a feature for facilitating insertion into the evacuated nucleus space through a minimal opening into said space, for example, about 12 mm by 12 mm. The closed spring loop defining an open interior defined by an interior loop spring wall surface, the exterior wall of the closed spring loop being elastically deflectable toward the base under loading.

[0025] In embodiments, an assembled disc nucleus prosthesis has a greatest dimension extending in a lateral direction, has a second greatest dimension extending in a posterior anterior direction, and has the third greatest dimension extending in a superior inferiorAttorney Docket No. 5364.002W01direction. The nucleus prosthesis having a superior facing convex surface defined by a laterally extending row of external walls of a plurality of spring loops. Each spring loop engaging at least one adjacent spring loop at a linear juncture whereby there are at least three parallel linear junctures extending in an anterior posterior direction. Wherein each of the exterior walls of each of the spring loops are slidingly movable with respect to an exterior wall of an adjacent spring loop.

[0026] In embodiments, a implant segment of a nucleus prosthesis has one or two lobe members extending from a base region, the base region having features allowing insertion of the segment into an evacuated nucleus.

[0027] In other embodiments, the segment may include an anterior section with a greater height when compared to, for example, the height of an associated posterior section either before or after positioning, or alternatively both before and after positioning. The differences in the heights of the posterior and anterior sections of the segment allow the prothesis to conform to and to impact the natural curvature of the spine as it varies along the length of the spine as well as in varying spinal curvatures from patient to patient needing treatment with the use of the prosthesis.

[0028] In some embodiments the anterior height of a segment is adapted or configured to vary in height during, for example, placement and position. One embodiment, for example, configures the height of the anterior portion of the segment to a desired specification before placement and then the height is adjusted after the segment is in a final position. This allows the anterior section to have a reduced height in order to pass through a port of restricted size caused by the superior-inferior height gap between posterior corners of the opposing vertebral plates of the disc at issue. After insertion, positioning, and connection to the previously inserted implant segment, the superior-inferior thickness is increased or expanded within the annulus cavity when properly positioned. In another embodiment, for example, the height of the segment is adjusted during the placement process again to facilitate passing through the vertebral plate gap and annulus opening and as the segment moves into and is seated at a final position the height of the anterior portion increases or expands within the excavated cavity. A variety of configurations and conditions may provide this adaptation or configuration of the height of the anterior section of segment including but not limited to segment materials, suitable restraints or restricting structures as well as tools and placement techniques selected to provide a controlled and variable height of the anterior section facilitating installation in the evacuated nucleus space.Attorney Docket No. 5364.002W01

[0029] In embodiments, a spring insert positioned between the base with interfacing features and the exterior wall provides a fulcrum effect such that when the posterior gap between a superior C-shaped wall and the inferior C-shaped wall is increased during the insertion of the segment through the port, the forward anterior portion of the segment contracts vertically reducing the height of the segment which may facilitate passage through a limited height insertion port. In embodiments, a insertion rod may have a segment engagement end, a user manipulating end and a wedge portion positioned at a posterior gap between the superior lobe and inferior lobe such that when a forward insertion force is applied to the insertion rod engaged with the segment, the gap between the superior and inferior lobe at the posterior end increases and the anterior section of the segment then contracts as the spring members act as a diffuse fulcrums.

[0030] In embodiments, a installation tool may engage an interior webbing in the anterior section of a segment to cause a vertical contraction of the anterior portion.

[0031] In embodiments, individual segments may be secured in a contracted state with removable or releasable constraints that are effectuated when the segments are in the evacuated nucleus space.

[0032] In embodiments, the base portion of a segment extends to engage forward ends of C-shaped superior external wall and the C-shaped inferior external wall such that insertion forces applied to the base portion are transmitted to the forward ends of the external walls. This then minimizes any shear forces between the base portion and the superior lobe and inferior lobe, more specifically minimizing shear forces between the base portion and the spring inserts, and between the spring inserts and the C-shaped external walls. In embodiments, the base portion has a forward extending cam portion that engages anterior ends of the C-shaped external walls to urge the anterior ends inward toward one another when the cam portion is moved forward with respect to the ends. Such cam action may reduce the vertical thickness of the anterior section of die segment by.5 to 3 mm, for example.

[0033] A feature and advantage of embodiments is that the surgeon implanting described prosthesis can avoid removal of portions of the vertebral plates in the installation. The superior-inferior gap defined by the posterior corners of the vertebral plates can be accommodated by the embodiments and methods herein. In embodiments, the C-shaped superior wall and C-shaped inferior wall may contact the posterior corners of the vertebral plates of a spine segment and the smooth exterior surface thereof facilitating sliding through the gap defined by the posterior corners. In embodiments, the forward anterior end of dieAttorney Docket No. 5364.002W01implant segment may compress by engagement of the posterior corners of the vertebral plates facilitating initial insertion while the posterior end may expand, wherein the central portion may be compressed as the implant segment is slid into the evacuated nucleus space.

[0034] A feature and advantage of embodiments, is that a lordotic shaped nucleus prosthesis with in situ assembly capabilities and serial insertion through a access port sized and

[0035] A feature and advantage of embodiments is that implant segments of a nucleus pulposis prosthesis to be assembled in situ may have a maximum superior-inferior thickness that is greater than the access port height defined by the gap between posterior corners of the vertebral endplates but may still be installed with reduced chance of breakage and with increased ease by way of reducing the maximum height before or during insertion through the access port.

[0036] The inventors have recognized that prior art implant segments utilizing solid homogeneous elastomeric material for the modular implant segment have inherent issues associated with the elastomeric material. Insertion tool interfaces do not make a high integrity connection to the elastomeric tool interfaces, reducing manipulative control within the evacuated nucleus space. Additionally, the sliding interface of elastomeric material to elastomeric material when connecting segments in situ is challenging due to the typical high friction between such components. Moreover, when compressed the elastomeric material absorbs the compression in three dimensions. That is, under superior-inferior compression, there is expansion in all direction in the transverse plane. Tills can inhibit ideal distinct deflection interaction between the different segments. Attempts to mount solid elastomeric lobes to rigid base portions with adjacent segment interfaces have not seen success. It is understood that this is due, at least in part, to an issue of the lobes delaminating from the rigid base portions. Such separation of components is highly undesirable in the context of implantable prostheses. In embodiments, elastomeric material is utilized that is overmolded onto and / or within capture structure unitary with the rigid base portion. This can include interior rails having a T-shape, pass through loops where the elastomeric material extends through the rigid loops, and interdigitation between the elastomeric material and the rigid base portion. In embodiments, the elastomeric material is captured between rigid spring members defining at least a portion of outer periphery of the spring lobes, utilizing such capture structures on both the rigid spring members and the interfacing base portion. In embodiments, the elastomeric material having voids therein to facilitate compression and reduce lateral expansion. Such voids can also facilitate insertion through the access port toAttorney Docket No. 5364.002W01the evacuated nucleus space, including by facilitating superior inferior contraction during the segment insertion into and through the access port. Such can be induced by utilization of the insertion tools, causing an active contraction by a superior-inferior contraction mechanism in the implant segment, and / or by the contraction forced by the posterior corner of the adjacent vertebral plates. The superior-inferior contraction mechanism may be, for example, an internal web spanning between a superior lobe and an inferior lobe such that anterior deflection of the central portion of the web pulls the superior lobe and inferior lobe together reducing the superior-inferior thickness. The web may be centrally positioned with respect to the posterior-anterior length of the segment, or may be anteriorly positioned. In embodiments, the superior-inferior contraction may be provided by elongation of the overall segment by exerting anterior displacement of an anterior nose portion of the implant segment with respect to the implant base portion. In embodiments, the superior-inferior contraction may be provided by cam surfaces of the implant segment interacting with cam surfaces of an insertion tool. In embodiments, a dissolvable or releasable contraction restraint may be installed between structure of the superior lobe and the anterior lobe, such that the contraction restraint releases after implantation. In single lobe embodiments of the implant segments, the single spring lobe may interact, as described with respect to the two lobe embodiments, with a rigid C-shaped outer wall oppositely positioned from the single spring lobe.

[0037] In embodiments, a nucleus prosthesis can be customized in the operating room. A variety of differently configured and sized segments and differently sized and configured segment spring inserts can be kept in inventor. When the patient is in surgery, the size of the cavity of the evacuated nucleus pulposus can be measured, the lordotic angle can be measured, and other desired specifications, such as compressibility of the segment may be selected. From these parameters, particular segments (and / or segment inserts) may be selected from inventory and implanted into the patient in the evacuated cavity. In embodiments, particular segments or spring inserts may be printed or otherwise formed as needed for a particular patient and then assembled to provide a particular size, configuration, and with specific functional characteristics, such as compressibility, of a prosthesis. Such customization can include utilizing segments that are tapered in the posterior anterior direction for implantation in a lordotic spine. Specific segments with particular lordotic angles and shapes can be kept in inventory to allow proper sized segments to be available during surgery.

[0038] Wherein the interconnected segments form an integrated unitary structure configured to mimic biomechanical properties of a natural intervertebral disc.Attorney Docket No. 5364.002W01

[0039] In some examples, the disclosure describes a method of implanting an intervertebral disc prosthesis, including sequentially inserting a plurality of modular implant segments into a disc space within an annulus fibrosus, each implant segment including structural channels to facilitate compression in response to an external force; and connecting each implant segment to an adjacent implant segment using a connection mechanism to form a unitary intervertebral disc prosthesis.

[0040] In some examples, the disclosure describes a system for replacing a nucleus pulposus, including a plurality of modular implant segments, each segment including a body formed of a biocompatible thermoplastic material; structural channels within the body configured as spring elements; and interlocking features for connecting to adjacent segments; and an insertion tool configured to sequentially insert and connect the modular implant segments within an intervertebral disc space.

[0041] The foregoing general description of the illustrative embodiments and the following detailed description thereof are merely exemplary aspects of the teachings of this disclosure and are not restrictive.BRIEF DESCRIPTION OF FIGURES

[0042] Non-limiting and non-exhaustive examples are described with reference to the following figures.

[0043] FIG. 1 A is a conceptual view on a sagittal plane of a surgical channel to an evacuated nucleus space in a lordotic spine and with a Prior Art prosthesis in the evacuated nucleus space.

[0044] FIG. IB is a conceptual view on a sagittal plane showing the insertion of a Prior Art implant segment of a nucleus prosthesis before insertion through a restricted access port to the evacuated nucleus space of a lordotic spine, the access port defined by vertebrae disc plates, the implant segment having a conventional Prior Art insertion tool.

[0045] FIG. 1C is a conceptual view on a sagittal plane of the FIG IB Prior Art implant segment being deformed upon insertion through the access port.

[0046] FIG. ID is a conceptual view on a sagittal plane of the FIG IB Prior Art implant segment being further deformed upon further insertion through the access port.

[0047] FIG. 2A depicts a superior conceptual view of a nucleus pulposus in an annulus fibrosus on a vertebral body.

[0048] FIG. 2B depicts a lateral sagittal view of a spine with lordotic discs.Attorney Docket No. 5364.002W01

[0049] FIG. 3 A depicts the superior view of FIG. 1A with the nucleus pulposis removed and an access port through the annulus fibrosus.

[0050] FIG. 3B depicts the sagittal view of the spine of FIG. 2B with the surgical access to the evacuated nucleus space and with the access port between the posterior corners of the adjacent vertebral plates.

[0051] FIG. 4A depicts the superior view of FIG. 1A with an assembled nucleus prosthesis implanted therein.

[0052] FIG. 4B depicts the side view of a spine of FIG. 3B with an implant segment in accord with embodiment placed therein.

[0053] FIG. 5 illustrates a conceptual lateral view of a implant segment prior to being inserted through the access port defined by the posterior corners of the adjacent vertebral plates

[0054] FIG. 6 is the conceptual lateral view of the implant segment of FIG. 5 illustrating an insertion tool effectuating outward forces on the posterior portions of lobes of the implant segment.

[0055] FIG. 7 is the conceptual lateral view of the implant segment of FIGS. 5 and 6, with the anterior portion of the implant segment contracted as the posterior section is expanded to slidingly fit through the access port.

[0056] FIG. 8A illustrates a conceptual lateral view of an implant segment prior to being inserted through the access port defined by the posterior corners of the adjacent vertebral plates with an insertion tool effectuating a force internal to the implant segment to contract the anterior lobes.

[0057] FIG. 8B is the conceptual lateral view of the implant segment of FIG. 8A with the anterior portion contracted to slidingly fit through the access port, the insertion tool having moved axially within the segment such as be a threaded interface between the insertion tool and base portion.

[0058] FIG. 9A is a conceptual lateral view of an implant segment abutting the posterior corners of the adjacent vertebral plates as the implant is being pushed into the access port.

[0059] FIG. 9B is the conceptual lateral view of the implant segment of FIG. 10A contracted by sliding engagement of rigid lobe surfaces during the sliding entry of the implant segment through tire access port and having a insertion force transmission member extending to the anterior most portion of the segment.

[0060] FIG. 10A is a conceptual lateral view of an implant segment abutting the posterior corners of the adjacent vertebral plates as die implant is being pushed into the access port.Attorney Docket No. 5364.002W01

[0061] FIG. 10B is the conceptual lateral view of the implant segment of FIG. 10A with sliding engagement of rigid lobe surfaces during the sliding entry of the implant segment through the access port and having a elongation member pushing forward on the inside of the nose portion for elongation of the segment and the consequential contraction in the superior inferior direction.

[0062] FIG. 11 illustrates a perspective view of an assembled nucleus disc prosthesis, according to aspects of the present disclosure.

[0063] FIG. 12 is a top plan view of the disc prosthesis of FIG. 2 A. The bottom plan view being identical thereto.

[0064] FIG. 13 is a front side elevation view of the disc prosthesis of FIG. 11.

[0065] FIG. 14 is aback side elevation view of the disc prosthesis of FIG. 11.

[0066] FIG. 15 is a back side perspective view of the disc prosthesis of FIG. 11.

[0067] another modular implant segment, in accordance with example embodiments.

[0068] FIG. 16 is an exploded view of the disc prosthesis of FIG. 11.

[0069] FIG. 17 is a perspective view of the left side end modular implant segment of the assembled disc prosthesis of FIG. II.

[0070] FIG. 18 is a perspective view of the left side end modular implant segment of the assembled disc prosthesis of FIG. I I.

[0071] FIG. 19 is a perspective view of an intermediate modular implant segment of the assembled disc prosthesis of FIG. 11.

[0072] FIG. 20 is another perspective view of the intermediate modular implant segment of FIG. 11.

[0073] FIG. 21 is a perspective view of the right-side end modular implant segment of the assembled disc prosthesis of FIG. II.

[0074] FIG. 22 is another perspective view of the right-side end modular implant segment of the assembled disc prosthesis of FIG. I I.

[0075] FIG. 23 is an exploded of an intermediate modular implant segment with the cantilever arm spring inserts displaced from the spring loop.

[0076] FIG. 24 illustrates a perspective view of an assembled nucleus disc prosthesis, with a single spring lobe, according to aspects of the present disclosure.

[0077] FIG. 25 is another perspective view of the disc prosthesis of FIG. 24.

[0078] FIG. 26 is a top plan view of the disc prosthesis of FIG. 24.

[0079] FIG. 27 is a bottom plan view of the disc prosthesis of FIG. 24.

[0080] FIG. 28 is side elevational view of die front side of the disc prosthesis of FIG. 24.Attorney Docket No. 5364.002W01

[0081] FIG. 29 is side elevational view of the back side of the disc prosthesis of FIG. 24.

[0082] end segment of the disc prosthesis of FIG. 24

[0083] FIG. 30 is a perspective view of the left side end implant segment of the disc prosthesis of FIG. 24

[0084] FIG. 31 is a perspective view of the left side end implant segment of the disc prosthesis of FIG. 24

[0085] FIG. 32 is a perspective view of an intermediate implant segment of the disc prosthesis of FIG. 24, the segment having a spring insert with cantilevered fingers.

[0086] FIG. 33 is a perspective view of the right-side end segment of the disc prosthesis of FIG. 24

[0087] FIG. 34 is an elevational view of an intermediate modular implant segment for a lordotic spine.

[0088] FIG. 35 is a perspective view of the intermediate modular implant segment of FIG. 34.

[0089] FIG. 36A is perspective view of an intermediate implant segment for a lordotic spine with two spring lobes.

[0090] FIG. 36B is a side elevational view of the intermediate implant segment of FIG.36A.

[0091] FIG. 37 is a side elevation view of the intermediate implant segment with the base portion having a force transfer member extending to the anterior loop.

[0092] FIG. 38 is perspective view of an intermediate implant segment for a lordotic spine, the segment having a single spring lobe.

[0093] FIG. 39 is a side elevational view of the intermediate implant segment of FIG. 38.

[0094] FIG. 40 is side elevation view of an intermediate implant segment for a lordotic spine having a force transfer member extending from the base portion to the anterior most portion of the segment.

[0095] FIG. 41 is plan view of an intermediate implant segment of FIG. 40 for a lordotic spine.

[0096] FIG. 42 is a side elevation view of the implant segment of FIG. 40.

[0097] FIG. 43 is perspective view of the posterior side of the implant segment for a lordotic spine of FIG. 40.

[0098] FIG. 44 is a perspective view of the anterior side of the intermediate implant segment of FIG. 40.Attorney Docket No. 5364.002W01

[0099] FIG. 45 is a side perspective view of the intermediate implant segment for a lordotic spine of FIG. 40.

[0100] FIG. 46 is a side perspective view, the opposite side of FIG. 45, of the intermediate implant segment of FIG. 40 for a lordotic spine.

[0101] FIG. 47 is perspective view of a nucleus prosthesis including the intermediate implant segments of Figs. 40-46..

[0102] FIG. 48 is an perspective view of an insert tool utilizable with the intermediate implant segments of FIG. 40-47.

[0103] FIG. 49 is a cross-sectional view of the intermediate implant segments of Figs. 40- 46

[0104] FIG. 50 is another cross-sectional view of the intermediate implant segments of Figs. 40-46

[0105] FIG. 51 is a side view showing an interaction between an insertion tool and an implant segment for providing an anterior end contraction.

[0106] FIG. 52 is another side view showing the engagement of the insertion tool of FIG.51 to expand the posterior end of the implant segment while contracting the anterior end of the implant segment.

[0107] FIG. 53 is another side view of the insertion tool and implant segment with flats on the insert tool engaged with the posterior ends of the outer C-shaped walls of the implant segment allow some rotational control of die implant segment with the insertion tool.

[0108] FIG. 54 is a perspective view of another implant segment with contraction means provided by cam follower surfaces.

[0109] FIG. 55 is a side elevational view of the implant segment of FIG. 54 that may cooperate with an insert tool having cam surfaces recessed in the end of the tool.

[0110] FIG. 56 is a side elevation view of the tool and segment of FIG 55 with the tool passing through the base portion confronting the cam follower surfaces on the anterior ends of the C-shaped outer walls.

[0111] FIG. 57 is a side elevation view of the tool and segment of FIG. 56 with the tool with cam surfaces engaging the cam follower surfaces of the anterior ends of the C-shaped outer walls for contracting the anterior end of the segment.

[0112] FIG. 58 is a perspective view of another implant segment and insertion tool that cooperates with the implant segment to contract the anterior end of the implant segment.

[0113] FIG. 59 is another perspective view of the implant segment and tool of FIG. 58.

[0114] FIG. 60 is a elevation view of the implant segment and tool of FIG. 58.Attorney Docket No. 5364.002W01

[0115] FIG. 61 is an elevation view of the insertion tool extending into the implant segment and pushing a web in a anterior direction effectuating a pulling together of the anterior end portions of the implant segment thereby contracting the anterior portion of the segment.

[0116] FIG. 62 is an exploded view of the implant segment of FIG. 59 to 61 illustrating an exoskeleton and elastomer material overmolded on the exoskeleton.

[0117] FIG. 63A is a perspective view of another embodiment of an implant segment with a contraction constraint means comprising dissolvable sutures.

[0118] FIG. 63B shows the sutures attached to the implant segment.

[0119] FIG. 63C depicts the sutures pulled taught causing contraction of the implant segment.

[0120] FIG. 64A depicts an elevation view of another implant segment with an internal web for contracting the anterior portion of the implant segment.

[0121] FIG. 64B is the segment of F1G.64A elongated and contracted by the insertion tool.

[0122] FIG. 65 is a perspective view of another exemplary embodiment of a nucleus prosthesis for implantation in a evacuated nucleus space.

[0123] FIG. 66 is a top plan view of the prosthesis of FIG. 65. The bottom view being a mirror image thereof.

[0124] FIG. 67 is a side elevation view of the prosthesis of FIG. 65.

[0125] FIG. 68 is another side elevation view of the prosthesis of FIG. 65 taken from the side opposite of the side of FIG. 67.

[0126] FIG. 69 is another perspective view of the posterior side of the prosthesis of FIG.65.

[0127] FIG. 70 is an elevation view of the anterior side of the prosthesis of FIG. 65.

[0128] FIG. 71 is an elevation view of the posterior side of the prosthesis of FIG. 65.

[0129] FIG. 72 is an exploded view of the prosthesis of FIG. 65 looking at the posterior side with the segments separated from one another.

[0130] FIG. 73 is another exploded view of the prosthesis of FIG. 65 looking at the anterior side with the segments separated from one another.

[0131] FIG. 74 is another exploded view showing die endo skeletal rigid pieces, the base portion, separated from the elastomeric portions.Attorney Docket No. 5364.002W01

[0132] FIG. 75A is a cross-sectional view showing bridges of the elastomeric material extending from the superior spring lobe to the inferior spring lobe through apertures in the base portion.

[0133] FIG. 75B is a side elevation view of an intermediate implant segment.

[0134] FIG. 75C is a side elevation view of the intermediate implant segment of FIG. 75B from the opposite side.

[0135] FIG. 76 illustrates an intermediate implant segment joining an end implant segment with guide-in surfaces from a tapering of an anterior end of one segment and a posterior end of an adjacent segment to facilitate the in vito connection.

[0136] FIG. 77 is a plan view of a nucleus prosthesis with the implant segments such as depicted in FIG. 74.

[0137] FIG. 78 is a side elevation view of another implant segment, the view from the opposite side being a mirror image.

[0138] FIG. 79 is a perspective view of the implant segment of FIG. 76, the view from the opposite side being a mirror image.

[0139] FIG. 80 is another perspective view of the implant segment of FIG. 76, the view from the opposite side being a mirror image.

[0140] FIG. 81 is a perspective view of another implant segment similar to the segment of FIGS. 76 to 78 but with fewer cantilevered fingers, the view from the opposite side being a mirror image.DETAILED DESCRIPTION

[0141] The following description sets forth exemplary aspects of the present disclosure. It should be recognized, however, that this description is not intended as a limitation on the scope of the present disclosure. Rather, the description also encompasses combinations and modifications to those exemplary aspects described herein.

[0142] This description incorporates by reference herein for all purposes the following published documents: U. S. Pat. Nos. 5,888,220; 7,267,690; 7,713,301; 8,038,718; 8,100,977; 8,123,750; 9,510,953; 10,195,048; 11,246,714; and 12,447,024. U. S. App. Publication Nos. US2004 / 0247641; US2006 / 0111726; and US2008 / 0071379. The references to U. S. patents in all sections of this application are herein incorporated by references in their entirety for all purposes. Components, methods, tools, materials illustrated and / or disclosed in such patents may be utilized with embodiments in this description. Incorporation by reference is discussed, for example, in MPEP section 2163.07(B).Attorney Docket No. 5364.002W01

[0143] Referring to FIG. 1 A- 1C, prior art posterior implantation of implant segments 6 have generally been of elastomeric segments, see for example, USP 11,246,714. Such segments entirely made of elastomeric material have had difficulties in insertion and in making in situ connections. A patient’s back 10 has a surgical channel 11 that leads to an access port 12 to an evacuated nucleus space 13. The access port 12 defined by removed material from an annulus fibrosis 16 and defined by posterior corners 14, 15 of vertebral plates 17,18 in a lordotic spine 20. Posterior insertion of nucleus implant segments in a lordotic spine presents challenges not addressed in the prior art. The superior anterior gap 22 between the posterior corners of a lordotic spine is less than the maximum superior-inferior thickness 24 of the evacuated nucleus space 13. Such gap can be in the range of 7 to 10 mm and the thickness of the insert segments can be more than that. Such creates issues in trying to insert segments that are reflective of the average superior inferior thickness of the evacuated nucleus space, such segments, typically being completely elastomeric, may squeeze in through the access port with difficulty, see FIGS. 1B-1D. Although surgical removal of portions of the posterior corner of the vertebral plates can allow accommodation of more conforming sized implant segments, such surgery is not preferred and makes the procedure much more invasive. Conventionally such segments 6 have generally parallel and / or symmetric superior surfaces and inferior surfaces about a transverse plane 25 such that they do not adequately form fit the evacuated nucleus space 13 of a lordotic vertebral segment. See FIG. 1A. Moreover, the shape of the evacuated nucleus space in a lordotic spinal segment has an increasing superior-inferior thickness to which conventional implant segment and nucleus prosthesis do not have a form fit.

[0144] The modular intervertebral nucleus pulposis prostheses described herein may provide a replacement for a damaged or degenerated nucleus pulposis in an intervertebral disc. The modular intervertebral disc prosthesis comprises a plurality of interconnected modular implant segments. The modular implant segments may be designed to be sequentially inserted and connected within an intervertebral disc space to form an integrated structure.

[0145] In some cases, the unitary structure formed by the interconnected modular implant segments may be configured to mimic the biomechanical properties of a natural intervertebral disc. The modular design may allow for minimally invasive insertion through a small annular opening while providing the ability to restore disc height and function once assembled in situ.

[0146] The modular implant segments may incorporate structural features that enable controlled compression and flexibility. In some cases, these structural features may includeAttorney Docket No. 5364.002W01spring lobe elements including spring loops and internal cantilevered fingers, and other compressible components integrated into the design of each segment. The combination of multiple interconnected segments with such compressible features may allow the assembled prosthesis to respond to physiological loads in a manner similar to a healthy natural disc.

[0147] In some cases, the modular intervertebral disc prosthesis may be customized to fit the specific anatomical requirements of individual patients. The number, size, and configuration of the modular implant segments may be selected based on factors such as the patient’s disc space dimensions, degree of degeneration, and desired range of motion. For example, each implant segment of a modular intervertebral disc prosthesis may have dimensions (e.g., length, width, thickness or height) that may be the same or different than adjacent implant segments selected to mimic the anatomy of a patient. In embodiments, the modular implant segments are suitable for implantation in a lordotic spine.

[0148] The modular approach may also facilitate revision or adjustment of the prosthesis if needed in the future. Individual segments may potentially be removed or replaced without necessitating removal of the entire prosthesis, which may provide advantages over singlepiece disc replacement devices.

[0149] Referring to FIGS. 2A-4B, aspects of embodiments are illustrated. FIG. 2A illustrates a nucleus pulposis 28 within the annulus fibrosis 16. The surgical channel 11 leads to the access port 12 to the evacuated nucleus space 13.

[0150] A disc nucleus replacement system 30 comprises, implant segments 32 that include two end implant segments 33, 35, and a plurality of intermediate implant segments 36 assemblable in situ into a nucleus prosthesis 38. The system 30 may include insertion tools 39 for serially insertion of the segments through the access port 12 and for manipulation and operation of mechanisms of the implant segments as described below, such implant segments and tools being particularly advantageous for nucleus disc replacement in lordotic spines with lordotic evacuated nucleus spaces. Referring in particular to FIG. 4A, an intermediate implant segment 36 that has posterior-superior thickness 37 greater than the posterior-superior gap 22 at the access port 12, is contracted through various means 39, illustrated generically by the dashed circle to a reduced thickness as illustrated by 36’ before or during insertion. After insertion into the evacuated nucleus space 13, the segment conforms to the shape of the space.

[0151] Referring to FIGS. 5, 6, and 7, conceptual lateral views of an implant segment 40 inserted through the access port 12 defined by the posterior corners 14,15 of the adjacent vertebral plates. An insertion tool 43 controlled by the surgeon, has two position within theAttorney Docket No. 5364.002W01segment 40. A first position 41 of FIG. 5 and then a second position 42 of FIGS. 6 and 7. The second position effectuating outward forces 44, 45 on the posterior portions 43 of lobes 47, 48 of the implant segment 40, such as by cam surfaces. In embodiments, the first and second lobes 4748have diffuse fulcrums such that said outward forces may effectuate tlie contraction of the anterior portions 50 of the lobes 47, 48. See also FIGS. 51 to 53 and the associated discussion below for specific embodiments consistent with these figures.

[0152] Referring to FIGS. 8A and 8B, in embodiments, an implant segment 53 has an insertion tool 54 that as illustrated has two positions within the implant segment, and as the insertion tool 54 moves to the second position, internal forces 56, 57 act to pull the first lobe 58 and second lobe 59 toward each other, causing contraction of the anterior end, which may be prior to engaging the access port 12 defined by the posterior corners 14, 15 of the adjacent vertebral plates. The insertion tool may be threadedly engaged with the base portion 60 for maintaining the axial position of the insertion tool with respect to the segment. See FIGS. 58- 61 and 64A-64B and the associated discussion below for specific embodiments consistent with these figures.

[0153] Referring to FIGS. 9A and 9B, in embodiments, an implant segment 64 is abutting the posterior corners 14, 15 of the adjacent vertebral plates as the implant 64 is being pushed into the access port 12 by an insertion tool 65. The insertion tool 65 is inserted into the base portion 67 and has a single seated position as seen in both FIGS 9A and FIG. 9B. A rigid force transmission member 69 extends from the base portion to an anterior-most portion 70 of the segment configured as a nose. Tapered surfaces 65, 66 on the anterior portions of the first and second lobes 67, 68 are formed of a rigid material, such as PEEK or titanium. The tapered surfaces effectuates the contraction of the two lobes at the anterior portion as indicated by the forces 72, 73, as the segment slidingly engages the posterior corners 14, 15. Spring members 74, 75 in the lobes compress. The rigid force transmission member facilitates contraction and some posterior motion of the two spring lobes as the segment is being inserted.

[0154] Referring to FIGS. 10A and 10B, FIG. 10A is a conceptual lateral view of an embodiment of an implant segment 77 abutting the posterior corners 14, 15 of the adjacent vertebral plates as the implant segment 77 is being pushed into the access port 12. The insertion tool 79 extends through base portion 80 and is slidingly engaged therewith to abuttingly engage apply a anterior force 81 on the nose portion 82 of the implant segment 77. The nose being anteriorly displaceable with respect to the base portion 80. When the nose portion 82 is moved anteriorly with respect to die base portion 80, the segment elongatesAttorney Docket No. 5364.002W01effectuating a contraction in the superior inferior direction. The tapered surfaces 84, 85 in cooperation with the posterior corners also provide a contraction force at the posterior corners to facilitate the segment contraction in the superior-inferior direction aiding the insertion.

[0155] Referring to FIG. 11, am assembled nucleus pulposus prosthesis 100 is illustrated with anatomical directional terms associated with its implant position in cavity in an annulus fibrosus of a human spine. Referring to Figs. 11-16, the prosthesis is comprised of a plurality of modular implant segments 104 including a left side end segment 106, three identical intermediate segments 107 and a right-side end segment 110. The assembled prosthesis generally has superior face, or upper exterior wall 114 with a smooth convex wall surface 116, as well as a corresponding inferior face, or lower exterior wall 118 with a smooth convex wall surface 120. The prosthesis superior facing and inferior facing walls are formed by outer exposed walls of the assembled modular disc segments. The superior wall surface and inferior wall surface are continuous and uninterrupted except for the juncture lines 120 between the adjacent segments. A posterior side 126 and an anterior side 128 of the prosthesis have respective central recesses 130, 131 extending the lateral length of the prosthesis at a prosthesis base 135. Above the prosthesis base is a compressible upper portion 137 that includes the upper exterior wall 116 that will engage the vertebra immediately thereabove and a compressible lower portion 139 that includes the lower wall 118 that will engage the adjacent vertebra. The prosthesis upper portion 137 projects anteriorly and posteriorly as does the prosthesis lower portion. Positioned between the compressible upper portion and the prosthesis base are open cavities and structure providing for the controlled deflection and compression and rebound of the upper portion with respect to the prosthesis base 135. Similarly, positioned between the compressible lower portion and the prosthesis base are open cavities and structure providing for the controlled deflection and compression and rebound of the lower portion with respect to the prosthesis base 135.

[0156] Referring to FIG. 16-22, the individual modular disc segments that are assembled in providing the prosthesis are illustrated. Each segment has a central base portion 150 and an upper spring lobe, 152 and a lower spring lobe 154. The upper and lower spring lobes being unitary with the central base portion. The base portion of each segment includes at least one connector portion 158 and further includes an insertion tool interface 160. The intermediate segments 107, as best shown in Figs. 9 and 10, have opposing connector portions, one being a male sliding member 163 and the opposing connector portion being a cooperating female slot 165. The intermediate segment spring lobes 152, 154 each comprise a spring loop portions 170, 172 that extend from each of the anterior and posterior sides ofAttorney Docket No. 5364.002W01the base portion in anterior and posterior directions. The spring loop portions extend generally straight outwardly, have a smooth curve to loop around. Each spring loop portion 170, 172 has an anteriorly projecting spring loop portion 176 and a posteriorly projecting loop portion 178. When under compression, such as by the patient flexing and / or extending their spine, the pairs of posteriorly projecting loop portions and / or the pairs of anteriorly projecting loop portions may compress and move closer together. Upon compression of the loop portions, a set 179 of internal cantilevered spring members 180 absorb and resist such compression. Each cantilevered spring member or finger has an anchored end 183, and a free or unanchored end 184. The unanchored end confronts and / or engages the inside surface of the wall of the spring loop portion and as the spring loop is compressed slidingly engages the wall surface and simultaneously bends. As the fingers bend more resistance may increase providing for greater resistance to compression of the spring loop. The spring lobes may also have internal stops 187 configured as vertical posts that prevent a central portion of the spring loop portion from deflecting more than a desired distance toward the base portion.

[0157] Referring to FIG. 23, in embodiments, an insert 188 including the set 179 of cantilevered fingers 180 may extend from a finger base portion that may be separately formed from the segment base portion and spring loop portions of the intermediate segments. The insert may then be inserted into the open interior of the spring lobes and secured therein by welding, fasteners, or other means. In embodiments, such an insert may have the fingers extending toward the base portion rather than the distal portion of the spring loop portion.

[0158] Although the segments of the nucleus pulposus prosthesis of Figs. 11-23 have two lobes, in embodiments, segments may also have a single spring lobe, see Figs. 24-33. The upper spring lobe may all have the same features and elements of the spring lobes of the segments of the FIG. 11-23 prosthesis. The single lobe prosthesis 300 has the compressible upper portion 310 formed by the collective spring lobes of the assembled modular disc segments 316, and has the prosthesis base 318, and further has a lower spring plate 322. The lower spring plate may be configured to have the same configuration as the compressible upper portion 310. Such a prosthesis may have less height suitable for particular patients and / or particular vertebra spaces.

[0159] Referring to Figs. 24-38, alternative configurations of intermediate modular disc segments may be formed with tapered sections from the anterior to posterior sides or sections or vice versa. Generally these taper to the posterior end and are for lordotic nucleus disk spaces.Attorney Docket No. 5364.002W01

[0160] Figs. 34-37 illustrate an embodiment of a tapered implant segment. Specifically, FIG. 34 is a side view a segment that has a tapered configuration with anterior section 416, 417 having a height greater than the corresponding height of posterior sections 418, 419. Perspective view FIG. 35 also illustrates this tapered configuration from the anterior sections to the posterior sections and also sets out base 412 fitted between the superior wall and the inferior wall and a spring segment 413 associated with base 412. FIG. 36 is another perspective view of the segment of FIG. 34. In this view, the superior region of segment 402 includes a superior lead end 420 and a superior trailing end 421. This embodiment also includes inferior region 404 with an inferior lead end 430 and inferior trailing end 430. These leading ends 420 and 430 are both contractile nose portions of the segment that will be the initial part of the segment to pass through the annulus for placement and positioning in the evacuated cavity remaining after the disc is removed. The segment of this embodiment and related segments may be suitable for implanting in patients with lordotic spines. The additional spring 413 is provided between a pair of posterior projecting contractile noses portions to provide a supplemental spring to provide a greater resistance to the compression of the anterior side of the segments and assembled prosthesis.

[0161] Figs. 38 and 39 illustrate another embodiment of a segment suitable for a prosthesis described in this specification. 'These figures are directed to a segment with a contractile superior section 502, a base 504 and an inferior section 506. In this embodiment, the inferior section will have, for example, different compaction properties compared to superior section. The inferior section may be made of a suitable elastomeric material that is biocompatible with the vertebrate adjacent the cavity space containing the prosthesis. The contact between the prothesis and an adjacent vertebrate, for example, is illustrated in FIG.32. This cross-section view schematically shows an exterior surface of the prosthesis 602 contacting an exposed vertebrate 604 when the prothesis is containing in a cavity created by removing all or most of the disc requiring surgical intervention and treatment.

[0162] Figs 37 and 40-47 are multiple views of another embodiment of a segment. In this embodiment the segment includes a region of elastomeric polymer material that provides compaction and torsional characteristics to the segment. The elastomeric polymer is an alternative to the fingers and spring characteristics for alternative embodiments set out is this description. In embodiments, segment 600 is a generally C-shaped segmented prosthesis segment that is tapered from an anterior section to a posterior section. Segment 600 includes superior (or upper) exterior wall 610 that has anterior lead end 612 and posterior trailing end 614. This segment also includes inferior (or lower) exterior wall that has anterior lead endAttorney Docket No. 5364.002W01616 and posterior trailing end 617. The segment of this embodiment further includes upper and lower elastomer structure 620, 621 to provide compression and torsion characteristic needed for the prosthesis to function as a replacement for the disc removed during surgery. Elastomer structure 620, 621 is an alternative to the fingers or springs described above. The elastomer structure is made or manufactured from, for example, biocompatible elastomeric polymers that are fitted in the space between the exterior walls and a base. This embodiment includes a base 630 that includes attachment structure adapted for tools used for placement and positioning 632 and a forward base extension 633. Base 630 also includes connecting portion 634 that interfaces and contacts additional segments to form a prothesis in situ within the cavity. FIG. 41 illustrates another view of the connecting portion 634. In this embodiment the connecting portions are adapted to connect when a sliding male component 635 of first segment slides or fits into a related female component of an adjacent second segment.Another feature illustrated in Figs. 40 and 41 is a posterior recess 640 that allows access to base 630. Posterior access 640 allows use of a variety of placement and positioning devices and tools during surgery for disc repair and replacement. Figures 43-48 are additional views showing the elements and structures as described for FIG. 40. In particular, cross-section Figs. 37 and 38 illustrate elements associated with body 630 used to allow access and fitting of devices and tools for segment placement and positioning. These cross-section views, for example, show a threaded port 650 for attached of a threaded placement tool (not shown).

[0163] Figures 40-42 are multiple planar views of another embodiment modular implant segment and Figures 43-46 are multiple isometric views of this modular implant segment. Figures 40-42 illustrate module segment 700 having a C-shaped superior spring lobe 702 and a corresponding C-shaped inferior spring lobe. Lobes 702 and 704 include a resilient compressible spring lobe, superior spring lobes 702a and inferior spring lobe 704a. The resilient spring lobes 702a, 704a interface with rigid base segment 710. FIG. 41 shows a component of rigid base segment 710 that is a male implant segment interface portion 711 allowing segments to attach to another rigid base segment (not shown) placed adjacent to module segment 700. The segment interface portion of the rigid base are also illustrated Figs.40 and 42. Fig 40 illustrates a female segment interface portion 712 in a generally interior portion of the implant segment as shown in isometric Figs 43 and 44. Male segment interface portion 711 is shown in FIG.42 and in this embodiment is in a generally exterior portion of the implant segment in order to can slidably engage with the corresponding female segment interface portion of a second implant segment.:4Attorney Docket No. 5364.002W01

[0164] The attachment of the adjacent segments can occur in situ during a surgical procedure. FIG. 47 is another isometric view illustrating multiple implant segments 720 that are connected to adjacent segments by the rigid segment base portion of each implant segment. The use of multiple implant segments allows the assembly of the nuclear prosthesis during a surgical procedure that needs relatively minimum access to a disk to be treated, reducing complications and associated risks for other types of spinal disc surgical procedures.

[0165] The various embodiments of implant segments described in this description allow the surgeon to select appropriate tools, instruments and accessories for accessing. FIG. 48 is an embodiment of a suitable implant tool 800. Implant tool 800 includes rigid base interface 802 to engage the rigid base, cam tool segment 802, spring lobe interface segment 806, and shaft 808. Implant tool 800 is used with an implant segment 820 illustrated in FIGS. 49-50. Implant segment 820 illustrated in cut-away isometric view Fig. 49 includes C-shaped superior side or surface, 822, C-shaped inferior side or surface 824, superior spring lobe 826 and inferior spring lobe 828, and rigid base portion 830. Rigid based portion 830 includes male segment interface portion 831, female interface segment portion 832, rigid base interface portion 834. These features are also illustrated in another cut-away isometric view FIG. 50, showing C-shaped superior side or surface, 822, superior spring lobe 826 and inferior spring lobe 828, and rigid base portion 830. Rigid based portion 830 includes male segment interface portion 831, female interface segment portion 832, rigid base interface portion 834. During the disc replacement procedure implant tool 800 engages rigid based interface portion 834 to allow the surgeon to guide and place the implant segment as needed into to form the multiple segments into the nucleus prothesis.

[0166] Figures 51-53 illustrate engaging implant tool 800 with implant segment 820. Implant tool 800 is passed through the posterior side of the segment between the space between the superior side and the inferior side. Rigid base segment portion 802 of the tool engages the tool interface 834 of the rigid base and can move into the anterior portion of the rigid base. As the tool moves into the anterior portion of the rigid base, cam tool segment 804 engages the posterior edges 822a, 824a of the superior and interior sides causing the superior and inferior edges to move apart or increase the space between the posterior superior and interior sides. When this spacing increases, the anterior edges of the superior and inferior sides move closer to each other or the movement decreases the space between anterior edges 842, 844, of the of superior and inferior sides. Fig. 52 illustrates engaging of the tool with the rigid base with the resulting narrowing or closing of the anterior edges of the segment as the posterior edges of the segment contact the cam segment of the tool. The movement of theAttorney Docket No. 5364.002W01superior and inferior sides is facilitated by the selected attachment of the spring lobes 826, 828 to the rigid base 820. The springs lobes attach to the rigid base in the regions of 826a and 828a. Selective attachment provides a fulcrum for the superior and interior sides to move as the tool cam engages the rigid base so that the space narrows the anterior side of the segment so that this side is smaller or reduced. Reducing the anterior side of the implant segment facilitates moving the segment through the surgical opening of the spine and then into the evacuated disc space. FIG. 53 further illustrates more movement of the tool into a seated position so that the cam following portion of the superior side 822a and the interior side 824a engage spring lobe portion 806 of the tool. In this position, the implant segment is fixed to the tool to allow additional movement of the implant segment using the tool including, for example, rotation of the implant segment during positioning and placement.

[0167] Figures 54-57 are perspective and side views to an embodiment of an implant segment 900 with contraction means on the anterior edges of the superior side and inferior side of the implant segment. Fig 54 shows cam follower surfaces 902, 904. FIG. 55 illustrates how an insert tool 910 has cam surfaces 912 recessed in the end of the tool. Fig. 56 shows insertion tool 910 passing through rigid segment base portion 906 confronting the cam follower surfaces on the anterior ends of the C-shaped outer walls. As insertion tool continues to move into the anterior region of the implant segment, insertion tool 910 with cam surfaces 912 engages the cam follower surfaces 902, 904 of the anterior ends of the C-shaped outer walls for contracting the anterior end of the segment. In a seated position illustrated in FIG.57, the insertion tool that cooperates with the implant segment to contract the anterior end of the implant segment.

[0168] Figures 58-62 are another embodiment of an implant segment and related implant tool. FIGS. 58 and 59 are perspective views of implant segment 1000 and insertion tool 1002 of FIG. 58. FIG. 60 illustrates implant segment 1000 having a web segment that is configured to interact with tool 1002. FIG. 61 illustrates insertion tool 1002 extending into the implant segment 1000 and pushing a web 1004 in an anterior direction effectuating a pulling together of the C-shaped outer walls 1005, 1006 which causes contraction of the superior-inferior height or thickness of the segment 1000. The threaded portion 1006.5 of the tool may engage with threaded portion in the base portion 1006.6 to allow incremental adjustment of the contraction. Such threaded connection provides robust attachment between the insertion tool and implant segment facilitating insertion through the access port. Implant 1000 may be formed from the components shown in Fig. 62 including an exo skeleton component 1006 and elastomer material 1007, 1008 overmolded on the exoskeleton. RigidAttorney Docket No. 5364.002W01loops 1008 may be unitary with the rigid C-shaped walls to allow the elastomeric material overmolded onto the walls to extend therethrough to be locked thereon.

[0169] FIG. 63 A- 63C illustrate another embodiment of an implant segment 1010 with a contraction constraint means 1011 comprising dissolvable sutures 1011. The implant segment may be manually contracted from the state of FIG. 63B and the suture pulled tight and tied as shown in FIG. 63C. Then the insertion tool 1012 can be attached to the implant segment for implanting the segment. FIG. 63A shows the sutures attached to the implant segment in a suitable relaxed but functional state. Such constraint means would be applied before implanting and would expect to dissolve in a matter of hours or days. Suture connectors, such as U-shaped fitting 1013 may be molded as part of the C-shaped outer walls 1014, 1015. As depicted the C-shaped walls connect to the base portion 1017 exclusively through the elastomeric spring Other dissolvable connection means may be utilized such as straps or connectors extending between the lobes.

[0170] FIG. 64A and 64B illustrate an embodiment of an implant segment 1020 with an internal web 1021 for contracting the anterior portion 1023 of the implant segment in cooperation with insertion tool 1022. In this embodiment, a first lobe 1024 comprises a first outer wall 1025 that is unitary and homogeneous with the segment base portion 1027 and extends to end 1028. A second lobe 1029 comprises a second outer wall 1030 that is unitary and homogeneous with the segment base portion 1027 and extends to end 1030 that confronts the end 1028 of the first outer wall. As the segment contracts by way of the insertion tool interfacing with the web 1021, the insertion tool and the web where it interfaces abuts the closed two ends 1028, 1030. Such allows, when the segment is pushed through the access port, some elongation of the segment, further

[0171] FIGS. 65-75 are exemplary embodiments of a nucleus prosthesis 1100 having multiple, connected implant segments for implantation in a evacuated nucleus space. The segments include two end segmen ts 1104, 1105 and a plurali ty of intermediate segments 1107. As seen from FIGS. 72-73 show an exploded view of the prosthesis of FIG. 65 looking at the anterior side with the segments separated from one another. The intermediate segments 1107 comprise a rigid base portion 1109, and a first lobe 1110 and a second lobe 1111. Each lobe has an outward surface with a C-shape when viewed laterally. FIG. 74 show's the endo skeletal rigid pieces, the base portions, separated from the elastomeric portions. The elastomeric portions may be overmolded onto the base portions.

[0172] FIG. 75A-75C shows an intermediate segment and illustrate an ovate shape with slight truncations about the longitudinal axis when viewed laterally. FIG. 75A show's a crossAttorney Docket No. 5364.002W01section at line 75A-75A of FIG. 75B showing bridges 1118, 1119 of the elastomeric material 1122 extending from the superior first spring lobe 1110 to the inferior second spring lobe 1111 through apertures 1125,1126 in the base portion to lock the lobes, which in this embodiment constitute the spring members to the rigid base portion 1109. The base portion has opposing adjacent segment connecting interfaces 1130, 1131. All of the segments except one end segment have tabs 1138 on the anterior end that when the each next segment is inserted and connected, the just inserted segment received the tab to essentially close the anterior end of the implant to provide the smooth and continuous anterior surface 1140 shown in FIGS. 65 and 70.

[0173] FIGS. 76 and 77 illustrates a conceptual intermediate implant segment 1 joining an end implant segment 1151 with guide-in surfaces 1160, 1161 from a tapering of an anterior end 1167 of one segment and a posterior end 1170 of an adjacent segment to facilitate the in vivo connection at the surgical side. When multiple segments are essentially configured like the embodiment of FIG. 76, the combined segments form nucleus prosthesis 1160. In other embodiments, the mouth 1162 of the receiving slot on the anterior ends of the modules can be widened to facilitate easier connection in situ. See the dotted lines 1164 on the fourth implant segment of FIG. 73.

[0174] FIGS. 78-81 illustrate multiple views of nucleus prosthesis implant segment 1180 having cantilevered fingers such as 1182, extending from a rigid base portion 1185 with hinged superior side 1194 as well as hinged inferior side 1196. In these embodiments, the base portion has the cantilevered fingers that slidingly engage the inside surface of the outer C-shaped wall when compressed FIG. 81 shows another implant segment embodiment 1170, similar to the segment of FIGS. 78-80, but with fewer cantilevered fingers 1171, but still including hinged superior side 1172 and inferior side 1174 sides. The

[0175] The elastomeric materials described herein may have Shore D hardness of about 40 to 80 and a compressive modulus in the range of about 6 to 50MPa.

[0176] “Rigid Polymers” when used herein may be polymers with a Youngs Modulus of greater than 3.0 GPa. In some embodiments, the modular implant segments as described herein may be formed from PEEK (polyether ether ketone) suitable for its biocompatibility and known physical characteristics. In other embodiments the segments may be constructed, manufactured or made from a titanium alloy instead of PEEK. The use of a titanium alloy may provide different mechanical properties and biocompatibility characteristics compared to PEEK, while still allowing for the controlled compression and flexibility of the modular implant segments. In other embodiments, one or more biocompatible polymers may be used.Attorney Docket No. 5364.002W01In certain embodiments, an elastomeric biocompatible polymer may used to make or manufacture some or all of the components of the disclosed prothesis and segments. A suitable biopolymer, for example, is commercially available under the brand BIONATE MEDICAL GRADE POLYMER (a polycarbonate polyurethane material sold by DSM Biomedical, Exton, PA., USA)..

[0177] In some cases, a method of implanting and assembling a modular intervertebral disc prosthesis may be provided. The method may involve sequentially inserting a plurality of modular implant segments into a disc space within an annulus fibrosus. FIG. 30 is a schematic description of a process to implant a modular disc implant, according to aspects of the present disclosure.

[0178] The implantation process may begin with applying a distraction force to adjacent vertebrae using a sequential dilator prior to inserting the modular implant segments. This distraction may create sufficient space within the intervertebral disc area to accommodate the prosthesis.

[0179] An insertion tool may be used to sequentially insert and connect the modular implant segments within the intervertebral disc space. In some cases, the insertion tool may be configured to grip and manipulate individual modular implant segments, facilitating their precise placement and connection within the disc space.

[0180] Each modular- implant segment may be inserted through a small pathway in the annulus fibrosus, such as illustrated in the figures. The segments may be designed to be inserted and assembled in situ, allowing for a minimally invasive surgical approach. In some cases, the modular implant segments may be inserted using a sequential dilator and distraction instrument, which may gradually increase the size of the insertion pathway while minimizing trauma to surrounding tissues.

[0181] As each modular implant segment is inserted, it may be connected to the previously inserted segment using a connection mechanism. This connection mechanism may allow for secure attachment between adjacent segments while still permitting some degree of flexibility. In some cases, the connection mechanism may include interlocking features that facilitate a slip fit connection between adjacent segments.

[0182] In embodiments, tire connection mechanism utilizes a male member configured as an elongate rail connected to a body portion of the base portion by way of a connection piece, for example a thinned pedestal extending the length of the elongate rail. The connection mechanism may further comprise an elongate slot projection extending from a lateral sideAttorney Docket No. 5364.002W01

[0183] The modular implant segments may include structural channels that form spring elements. These spring lobe elements may include superior compressible spring lobes positioned above a central base portion and inferior compressible spring lobes positioned below the central base portion. This configuration may allow the assembled prosthesis to mimic the biomechanical properties of a natural intervertebral disc.

[0184] As the final modular implant segment is inserted and connected, a unitary intervertebral disc prosthesis may be formed within the disc space. This unitary structure may be capable of bearing physiological loads and providing a range of motion similar to that of a healthy natural disc. In some cases, at least one channel (e.g., void) in the interior of a first modular implant segment aligns with at least one channel (e.g., void) in the interior of a second modular disc when the first modular implant segment and the second modular implant segment are aligned and adjacent to each other. In such cases, the alignment of the at least one channel of the first modular implant segment and the at least one channel of the second modular implant segment forms a continuous passageway through the first modular implant segment and the second modular implant segment. In such cases, the interior wall(s) forming the at least one channel in the interior of the first modular disc implant may align with the interior wall(s) forming the at least one channel in the interior of the second modular disc implant.

[0185] In some cases, the number of modular implant segments used may be determined based on the specific anatomical requirements of the patient. The sequential insertion and assembly process may allow for customization of the prosthesis size and configuration to best match the patient’s needs.

[0186] The method may also include verifying the proper placement and function of the assembled prosthesis using imaging techniques such as fluoroscopy or X-ray. In some cases, final adjustments to the positioning or compression of the modular implant segments may be made before completing the surgical procedure.

[0187] In some cases, the modular intervertebral disc prosthesis may include termination modular implant segments with a different arrangement of structural voids than the internal segments. These termination segments may be designed to provide specific mechanical properties at the ends of the assembled prosthesis, such as enhanced stability or improved integration with adjacent vertebral bodies.

[0188] The arrangement of structural voids in the termination segments may differ from the internal segments in various ways. For example, the termination segments may have fewer or more structural voids, or the voids may be arranged in a different pattern. In someAttorney Docket No. 5364.002W01cases, the structural voids in the termination segments may be oriented differently to provide specific directional stiffness or flexibility characteristics.

[0189] The modular intervertebral disc prosthesis may be customized in size and shape depending on patient needs. This customization may involve selecting different numbers, sizes, or configurations of modular implant segments to create a prosthesis that best matches the patient’s anatomy and biomechanical requirements.

[0190] In some cases, the customization process may involve using imaging techniques such as MRI or CT scans to determine the appropriate dimensions and shape of the prosthesis. Based on this information, specific modular implant segments may be selected, manufactures, or modified to achieve the desired overall prosthesis configuration.

[0191] The customization may also extend to the arrangement and design of the structural voids within individual modular implant segments. For example, the number, size, or shape of the structural voids may be adjusted to provide specific compression characteristics tailored to the patient’s needs.

[0192] In some cases, the materials used for the modular implant segments may be varied to achieve different mechanical properties. While polyether ether ketone (PEEK) may be commonly used, other biocompatible materials such as titanium alloys, cobalt-chromium alloys, or other polymers may be employed for specific applications or patient requirements.

[0193] The connection mechanisms between modular implant segments may also be subject to variation. While a slip fit connection may be used in some cases, alternative connection mechanisms such as snap-fit connections, threaded connections, or magnetic connections may be employed in other embodiments.

[0194] In some cases, the overall configuration of the modular intervertebral disc prosthesis may be modified to address specific clinical needs. For example, the prosthesis may be designed with an asymmetrical configuration to correct spinal alignment issues or to accommodate anatomical variations.

[0195] The modular nature of the prosthesis may allow for the incorporation of additional features or components. In some cases, the prosthesis may include integrated sensors for monitoring implant performance or tissue response. Alternatively, the prosthesis may be designed to incorporate drug delivery systems for local administration of therapeutic agents.

[0196] The structural voids within the modular implant segments may be filled with different materials in some embodiments. For example, the voids may be filled with a hydrogel material to enhance the viscoelastic properties of the prosthesis, or with a bone growth-promoting substance to encourage integration with surrounding tissues.Attorney Docket No. 5364.002W01

[0197] In some cases, the surface properties of the modular implant segments may be modified to enhance biocompatibility or promote tissue integration. This may involve surface treatments such as plasma spraying, chemical etching, or the application of bioactive coatings.

[0198] The modular intervertebral disc prosthesis may be designed to allow for post-implantation adjustments in some embodiments. This may involve the ability to add, remove, or replace individual modular implant segments without removing the entire prosthesis, providing flexibility for future revisions or adjustments as the patient’s needs change over time.

[0199] The modular intervertebral disc prosthesis provides benefits, for example, because segments are able to get sliding contact between the spring lobes and the top load bearing contact surface. This removes the need to make live hinges as in reported disc prothesis. The live hinges may not provide considerable load bearing capacity and are flexed a disproportionate amount relative to the rest of the structure, leading to stress concentrations and premature failures.

[0200] Mechanically, the modular intervertebral disc prosthesis maximizes the strain in a given volume of material. Material can only take so much strain and only has a given volume that will have an inherent limit to maximum stress / strain. In order to maximize the modular intervertebral disc prosthesis capacity strain should be distributed as evenly as possible, over as much material as possible. Getting ±1 millimeter (mm) of deflection in a 12mm cross¬ section of which roughly half of which is being used for other purposes (non-load bearing), while getting life in the millions of cycles, with a polymer, is quite demanding. The tapered shape of the various load supporting members allows for uniform strain distribution. The inclusion of a hard stop prevents stressing the device when a specified maximum deflection is reached, while still retaining the ability to support higher loads, without further compression of the device. The sliding contact elements allow for varying flexion of various load bearing members without the stress concentrations that would be seen with a live hinge. The uneven displacement and therefore strain distribution, is a consideration to get qualities above to align and is close to impossible without sliding contacts.

[0201] Preoperative Planning

[0202] Preoperative planning determines the height and lateral width of the modular nucleus pulposis that provides the best fit and fills in a patient’s evacuated nucleus space. Determine the approximate implant height required for the patient by using sagittal measurements of the intervertebral discs adjacent to the disc being treated on A-P MRI that isAttorney Docket No. 5364.002W01typically previously obtained. An alternative method is to use appropriate digitally aided lateral radiographs. The modular nucleus replacement device height that most closely matches the disc height of the nucleus space between the vertebrae plates disc to be treated is selected from an inventory (described below). The implant must fit securely between the endplates when the segment is fully distracted. The tallest possible implant, as determined by preoperative planning, is selected to maximize segmental stability.

[0203] Next, the approximate modular nucleus replacement device width to be implanted is also determined from the patient’s A-P MRI or lateral radiographs. The number of disc nucleus replacement segments to be used is selected in order for the modular disc nucleus replacement device to maximize contact with the peripheral margins of the endplates once assembled in-vivo.

[0204] It is understood that due to variations in radiographic magnification, these measurements provide only an estimate of an ideal implant size. Final device sizing must be performed just prior to implant insertion. Actual lateral dimensions of the modular disc nucleus replacement device are determined intraoperative! y by the ability to insert segments effectively.

[0205] Patient Positioning and Operative Procedure

[0206] The patient is positioned on a lumbar frame that promotes suitable exposure. Use of a Wilson frame (or similar) with the patient in a bent knee flexed position may be helpful for providing posterior distraction to the disc space, facilitating access for modular disc nucleus replacement device insertion. Use of C-arm intraoperative radiographic equipment during placement assures operative site selection, confirms the precise sizing and positioning of the modular disc nucleus replacement device implant, and minimizes surgical exposure.

[0207] Distraction

[0208] Distraction of the disc nucleus provides easier insertion of the modular disc nucleus replacement device segments. Distraction also aids in ensuring implantation of a modular disc nucleus replacement device with sufficient height for complete contact with the endplates following removal of distraction. Distraction can best be accomplished with the Spinous Spreader.

[0209] Place a spreader either between the laminae or at the base of the spinous processes of the appropriate levels and apply distraction. This method temporarily opens the posterior disc nucleus space and promotes increased exposure for access, decompression and delivery of the implant.Attorney Docket No. 5364.002W01

[0210] Note that distraction may need to be temporarily released after device segments are implanted, to facilitate movement of the device across the midline of the disc nucleus in preparation for implantation of subsequent segments.

[0211] Disc Access and Preparati on

[0212] Creating a sufficient unilateral window in the lamina allows surgical instruments and the implant to be inserted parallel to the vertebral endplates and also allows proper insertion of the implant segments. Extending the laminectomy to the medial border of tire inferior facet ensures the greatest ability to use instruments reaching across the midline of tire disc for removal of the contralateral nucleus and may aid in reducing contact with local nerve tissue.

[0213] Access to the disc is made via a vertical incision through the annulus using a #11 blade. Removal of annulus tissue should be minimized in order to ensure the smallest possible size of the annulus opening subsequent to modular disc nucleus replacement device implantation.

[0214] Completely remove the disc nucleus using a mechanical system and / or rongeurs. Complete nucleus removal, with special attention to removing the disc nucleus material contralateral and ipsilateral to the annulus access, will aid in the proper placement of the modular disc nucleus replacement device. Up-and down-biting rongeurs can be particularly useful in reaching across the midline of the disc. The anterior and lateral walls of the annulus must be preserved as well as the endplate cartilage. A representative removal device and procedure, for example, are reported in Issued US Patent 8,123,750 B2, incorporated by reference in this disclosure.

[0215] Removal of contralateral nucleus tissue is enhanced by flushing the disc nucleus space with saline after most of the nucleus has been removed, which serves to swell the nucleus material and place more of it within reach of the rongeur. The flushed disc is allowed to absorb the saline before removing the saline by suction and swollen nucleustissue. Repeating this procedure as needed is used until no more nucleus tissue can be removed.

[0216] Achieving complete removal of the nucleus while preserving the structural integrity of the annulus and the vertebral cartilaginous endplates ensures proper placement of the modular disc nucleus replacement device and a successful clinical outcome.

[0217] Implant Insertion

[0218] It is understood that using a mallet or other heavy instruments to pound on the implant segments may result in poor placement as the segments can be damaged or broken.Attorney Docket No. 5364.002W01Using only appropriate instruments provided or fingers to insert and remove segments helps prevent potential implant damage.

[0219] Insertion of the A Segment

[0220] The insertion process places the A segment by inserting the tail of the A segment into an Inserter Tool and aligning the tool with the segment. Insertion steps include inserting the A segment into the disc nucleus space such that the segment is oriented to the contralateral side of the disc nucleus space using the insertion tool (the segment may be protruding from the disc nucleus space), removing Inserter Tool, and moving the A segment contralaterally as necessary, using the facet joint as a fulcrum if needed.

[0221] Insertion of the B Segment

[0222] Next, the B segment is inserted adjacent to the A segment with the Inserter Tool. It is very important that the segments be parallel to each other when the B segment engages the A segment to prevent misalignment. Slowly and gently insert the B segment by pushing on the Inserter Tool while gently pulling back on the A segment to keep it in place. At this point the connection portions of the B segment will begin to engage with the A segment. At this point more force can be exerted on the insertion tool 1 until the B segment is fully inserted into the disc nucleus space and is properly aligned with the A segment. The inter¬ segment connection lock may be felt and / or heard to engage upon proper segment alignment.

[0223] It is understood that under no circumstances should any impact equipment or procedure be used during the insertion procedure. If any segment being implanted does not freely engage with the adjacent segment, stop the insertion process and proceed to eliminate potential obstructions or increase disc nucleus space distraction if appropriate.

[0224] After confirming by visual and / or tactile means that the two segments are fully engaged, this modular disc nucleus replacement device insertion process is repeated as needed to provide the assembled modular disc nucleus replacement device.

[0225] In the process for treating a candidate patient and implanting a modular disc nucleus replacement device for a good clinical outcome, the medical team may follow the steps set out numerically below.1) Localize level of herniation with Xray documentation using MRI data.2) Prep, drape and sterilize surgical field.3) Make a 2’ incision just lateral to the posterior spinal process of the superior vertebrae of the herniated motion segment.4) Retract muscle and facia down to the superior lamina of the motion segment involved.Attorney Docket No. 5364.002W015) Remove the proximal! / i of the superior laminae with a ronguer.6) Remove the herniated disc nucleus with a surgical Kerrison.7) Check for ligamentum flavuni hypertrophy or facet osteophytes in the lateral recess (remove if compressing nerve rootlets).8) Insert K-wire into the nucleus pulposus.9) Insert the first element of the progressive dilator over the K-wire past the edge of the end plates.10) Pass successive dilator elements to provide adequate passage of the morcellator.11) Proceed to clean out the nucleus pulposus.12) Insert the dilator ballon and overextend the endplate height by 1 to 2mm. 13) Take X-ray film of balloon filled with contrast.14) Deflate balloon and remove.15) Insert first segment and move medially and then remove attached inserter. 16) Insert second segment and move medially and then remove attached inserter.17) Insert third Segment and move medially and then remove attached inserter. 18) Insert fourth segment and move medially and then remove attached inserter.19) Remove progressive dilator.20) Reposition annulus fibrosis.21) Irrigate and suction.22) Remove muscle retractors.23) Close muscle and fascia24) Close skin25) Dress wound with pressure dressing.26) Transfer to post op recovery

[0226] An embodiment of this insertion process set out above is illustrated schematically in FIG. TO BE ADDED. Briefly, the insertion process uses the following steps. The surgeon can utilize modular implant segments 1102, each having structural voids to enable compression of the modular implant segments in response to an external force, and where each are constructed of a material configured to return towards its original geometric shape in response to diminution of the external force. The process includes implanting a first modular implant segments 1104, and in connection with implanting a second modular implant segment 1106, the surgeon can connect the second modular implant segment to the first modular disc nucleus implant using a connection mechanism provided on each of the first andAttorney Docket No. 5364.002W01second modular implant segments. The last of the modular implant segments is then implanted to form an aggregate intervertebral disc nucleus prosthesis in situ in a patient 1108.

[0227] Device Inventory and Surgical Kit

[0228] Good clinical outcomes for treating candidate patients with the modular disc nucleus replacement device described in the disclosure are improved when the segmented device is properly fitted and sized for each patient. The variability of physical characteristics of each patient requires access to an inventoried lot of ready-to-use devices.

[0229] The complete inventory will include devices of sufficiently shaped and sized devices that may be implanted at desired places along the spinal column, that will accommodate a range if specific patient’s having different anatomies, as well as series of shaped and sized devices that will allow fitting and placement adjustment within the operating theater. Although the approximate shape and size of a specific device may be made using various imaging technologies the final selection of any implanted device will be made in the operating room at the time of implantation as described above. A final shape and size determination will require actual measurement in the operating after the intra-vertebrate intersect is properly accessed and treated to operating room including the removal of the unwanted nucleus pulposus, and proper distraction of the adjacent vertebrate.

[0230] These considerations require an inventory of devices with a gross size and shape to accommodate differences in the anatomy of candidate patient’s as well as specific size and shapes to accommodate the intra-vertebrate space after nucleus pulposus removal and clean up. In practice, devices of gross overall shape and size will be prepped for implantation as well as devices with particular, specific size and shape to best match a patient’s unique anatomical characteristics associated with removal and clean up in the disc space to be treated.

[0231] During the surgical process to implant a modular disc nucleus replacement device, the operating room will have a supply of segments in the form of a surgical kit to provide a completed modular disc nucleus replacement device placed in a properly prepared intravertebrae space. The surgical kit will include various sizes and shapes of segments that have been selected to fit in intra- vertebrae space after the space has been prepared to remove the nucleus pulposus and suitable cleaned up. Due to the variation of the size and shape of this space that is specific to each patient receiving the modular disc nucleus replacement implant, the attending medical team will then select and implant the best fitting segments from the surgical kit to form the modular disc nucleus replacement implant by sequentially placing the proper segments. Optionally, the surgical kit will also include various instruments andAttorney Docket No. 5364.002W01apparatus that will serve to make the implanting process efficient and save, such as exact fitting instruments, sterilized to prevent infection, and easily identified to ensure accurate accountability during the procedure.

[0232] In some embodiments, some or all of the components of the disclosed systems and devices that are provided as a kit including complete with instructions for implementation and use. The instructions are provided on a tangible, non-transitory medium, and may be physically included with the kit such as on a printed document, compact disc, or flash drive. Non-limiting examples of a tangible, non-transitory medium include a paper document and computer-readable media including compact disc and magnetic storage devices (e.g., hard disk, flash drive, cartridge, floppy drive). The computer-readable media may be local or accessible over the internet. The instructions may be complete on a single medium or divided into two or more media. For example, some of the instructions may be written on a paper document that instruct the user to access one or more of the steps of the method over the internet, the internet-accessible steps being stored on a computer-readable medium or media. The instructions may embody the techniques and methods depicted or described herein using text, photos, videos, or a combination thereof to instruct and guide the user. The instructions may be in the form of written words, figures, photos, video presentations, or a combination thereof to instruct and guide the user.

[0233] When dimensions and parameters are provided, unless the context indicates otherwise, the dimensions and parameters reference a segment that is not deflected, under compression, or otherwise deformed.

[0234] When the term “portion” is utilized it means a part of a body, part of an assembly, or the whole of a part, component or something.

[0235] The foregoing description of representative embodiments has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Many modifications and variations are possible in light of the above teaching without departing from the broader scope and spirit of the disclosure. Teachings in the specification and drawings are therefore regarded as illustrative, and not restrictive. The invention covers alternatives, modifications, and equivalents that come within the scope and spirit of the principles set out herein and / or in the appended claims.

[0236] The accompanying drawings forming a part of the disclosure show, by way of illustration and not of limitation, particular representative embodiments in which the disclosed concepts may be practiced. Therefore, this Detailed Description is not to be takenAttorney Docket No. 5364.002W01in a limiting sense, and the scope of various embodiments is defined only by the appended claims, along with the full range of equivalents to which such claims are entitled.

[0237] The embodiments of the innovative subject matter may be collectively or individually referred to herein as the "invention" for convenience, without intending to restrict the scope of this application to any single invention or inventive concept if multiple concepts are disclosed. Therefore, while specific embodiments have been illustrated and described herein, it should be understood that any arrangement designed to achieve the same purpose may be substituted for die specific embodiments shown. This disclosure intends to encompass all adaptations or variations of various embodiments. Those skilled in the art will recognize combinations of the above embodiments and other embodiments not explicitly described herein upon reviewing the foregoing description.

[0238] The following United States patents are hereby incorporated by reference herein for all purposes: U. S. Pat. Nos. 5,888,220; 7,713,301; 8,038,718; 8,100,977; 8,123,750; 9,510,953; 10,195,048; 12,447,024 and 11,246,714. Published U. S. Patent Applications: US2004 / 0247641; US2006 / 0111726; and US2008 / 0071379 are hereby incorporated by reference herein for all purposes. The above references to U. S. patents in all sections of this application are herein incorporated by references in their entirety for all purposes.Components, methods, tools, materials illustrated and / or disclosed in such patents may be utilized with embodiments herein. Incorporation by reference is discussed, for example, in MPEP section 2163.07(B).

[0239] The above references in all sections of this application are herein incorporated by references in their entirety for all purposes. All of the features disclosed in this specification (including the references incorporated by reference, including any accompanying claims, abstract and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive.

[0240] Each feature disclosed in this specification (including references incorporated by reference, any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar- features.

[0241] The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any incorporated by reference references, any accompanyingAttorney Docket No. 5364.002W01claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed. The above references in all sections of this application are herein incorporated by references in their entirety for all purposes.

[0242] Although specific examples have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement calculated to achieve the same purpose could be substituted for the specific examples shown. This application is intended to cover adaptations or variations of the present subject matter. Therefore, it is intended that the invention be defined by the attached claims and their legal equivalents, as well as the following illustrative aspects. The above-described aspects embodiments of the invention are merely descriptive of its principles and are not to be considered limiting.Further modifications of the invention herein disclosed will occur to those skilled in the respective arts and all such modifications are deemed to be within the scope of the invention.

Claims

Attorney Docket No. 5364.002W01CLAIMS1. A disc nucleus replacement system comprising a plurality of modular implant segments for posterior serial insertion in an access port for in situ assembly into a nucleus prosthesis, the access port surgically created at a posterior portion of an annulus fibrosis of an intervertebral disc of a spine of a patient, the access port defined superiorly and inferiorly by posterior corners of opposing vertebral plates and laterally by removal of a posterior portion of the annulus fibrosis, wherein each of the plurality of modular implant segments having a pair of lateral sides, a posterior side, an anterior side, a superior side, and an inferior side, wherein the plurality of modular implant segments comprise a pair of end implant segments and a plurality of intermediate implant segments, wherein each of the intermediate implant segments comprising:a rigid segment base portion formed of a rigid material with a Youngs Modulus of greater than 3.0 GPa, the segment base portion having an adjacent implant segment interface portions defined on each of the pair of lateral sides of the segment base portion for connecting to adjacent implant segments, and further having an implant tool interface defined at a posterior side of the segment base portion;a first spring lobe positioned at one of the inferior and superior sides of each of said plurality of implant segments, the first lobe having a first smooth convex exterior C-shaped surface, the first spring lobe including a first compressible resilient spring component therein, the compressible resilient spring component separately formed from the interfacing base portion and being captured with respect to the interfacing base portion.

2. The disc nucleus replacement system of claim 1, wherein each of the plurality of implant segments further comprises a second spring lobe positioned at the other of the inferior and superior sides of each of said plurality of implant segments, the second spring lobe having a smooth convex exterior C-shaped surface, the second spring lobe including a second compressible resilient spring component therein, the second compressible resilient spring component separately formed from the segment base portion and being captured with respect to the segment base portion.

3. The disc nucleus replacement system of claim 1, wherein the first spring lobe of each of the plurality of implant segments is the only lobe of each of the plurality of implant segments, and wherein the first spring lobe comprises a first outer wall, the first outer wall formed of a rigid polymer with a Young’s Modulus of greater than 3.0 GPa, the outer wall having the firstAttorney Docket No. 5364.002W01smooth convex exterior C-shaped surface, and wherein each of the plurality of implant segments has a second C-shaped wall unitary with the segment base portion.

4. The disc nucleus replacement system of claim 2, wherein the first spring lobe of each of the plurality of implant segments comprises a first outer wall, the first outer wall formed of a rigid polymer with a Young’s Modulus of greater than 3.0 GPa, the outer wall having the first smooth convex exterior C-shaped surface, and wherein the second spring lobe of each of the plurality of implant segments comprises a second outer wall, the second outer wall formed of the rigid polymer with the Young’s Modulus of greater than 3.0 GPa, the second outer wall having the second smooth convex exterior C-shaped surface.

5. The disc nucleus replacement system of claim 4, wherein the segment base portion is formed of the rigid polymer with the Young’s Modulus of greater than 3.0 GPa,, and wherein the first outer wall is unitary and homogeneous with the segment base portion and extends therefrom at the superior side thereof, and wherein the second outer wall is unitary and homogeneous with the segment base portion and extends therefrom at an inferior side.

6. The disc nucleus replacement system of claim 5, wherein the first outer wall and segment base portion define a first closed loop of the first spring lobe, wherein the first compressible resilient spring component is captured in the first closed loop, wherein the second outer wall and segment base portion define a second closed loop of the second spring lobe, and wherein the second compressible resilient spring component is captured in the second closed loop.

7. The disc nucleus replacement system of claim 6, wherein the first compressible resilient spring component comprises a first plurality of cantilevered spring members that provide compression and resiliency by way of bending of the first cantilevered spring members, each of the first plurality of cantilevered spring members having one end unitary with a first spring base portion and a second end slidingly engaged or engageable with a rigid surface in the first closed loop, and wherein the second compressible resilient spring component comprises a second plurality of cantilevered spring members that provide compression and resiliency by way of bending of the second plurality of cantilevered spring members, each of the second plurality of cantilevered spring members having one end unitary with a second spring base portion and a second end slidingly engaged or engageable with a rigid surface in the first closed loop, wherein the first and second compressible resilient spring components are each formed of a rigid polymer with the Young’s Modulus of greater than 3.0 GPa.

8. The disc nucleus replacement system of claim 7, wherein the disc nucleus replacement system is for a lordotic segment of the spine of the patient, and when viewed laterally, each ofAttorney Docket No. 5364.002W01the plurality of intermediate implant segments have an ovate shape with a maximum superior-inferior thickness at an anterior half portion of each of the respective implant segments.

9. The disc nucleus replacement system of claim 8, wherein the segment base portion of each of the plurality of implant segments extends anteriorly to define or to abut an anterior- most portion of the implant segment.

10. The disc nucleus replacement system of claim 7, wherein, with respect to each of the plurality of implant segments, a posterior surface of the segment base portion is recessed inwardly from a posterior-most portion of the first closed loop and is recessed inwardly from the posterior-most portion of the second closed loop.

11. The disc nucleus replacement system of claim 10, wherein an anterior surface of the segment base portion is recessed inwardly from an anterior-most portion of the first closed loop and is recessed inwardly from the anterior-most portion of the second closed loop.

12. The disc nucleus replacement system of claim 11, wherein, with respect to each of the plurality of implant segments, a reinforcing member extends from and is unitary with an anterior portion of the first closed loop and connects to and is unitary with an anterior portion of the second closed loop.

13. The disc nucleus replacement system of claim 4, wherein, with respect to each of the plurality of intermediate implant segments, the first resilient compressible spring component comprises a first elastomeric insert, the elastomeric insert engaged and connected with the segment base portion and engaged and connected to the first outer wall, and wherein the second resilient compressible spring component comprises a second elastomeric insert engaged and connected with the segment base portion and engaged and connected to the second outer wall.

14. The disc nucleus replacement system of claim 13, with respect to each of the plurality of intermediate implant segments, the first elastomeric insert connecting to the first outer wall with elastomeric material mechanically locked about capture structure extending inwardly from the first outer wall, and wherein the second elastomeric insert with elastomeric material mechanically locked about capture structure extending inwardly from the second outer wall.

15. The disc nucleus replacement system of claim 14, with respect to each of the plurality of intermediate implant segments, the segment base portion of each of the plurality of implant segments has an anterior extension that engages with or defines an anterior-most portion of the implant segment.

16. The disc nucleus replacement system of claim 14, wherein the disc nucleus replacement system is for a lordotic segment of the spine of the patient, and when viewed laterally, each of the plurality of intermediate implant segments have an ovate shape with a maximum Superior-Attorney Docket No. 5364.002W01inferior thickness at an anterior half portion of each of the respective intermediate implant segments.

17. The disc nucleus replacement system of claim 14, wherein the disc nucleus replacement system is for a lordotic segment of the spine of the patient, and when viewed laterally, each of the plurality of intermediate implant segments have an ovate shape with a maximum superior-inferior thickness at an anterior half portion of each of the respective intermediate implant segments.

18. The disc nucleus replacement system of claim 17, wherein, with respect to each of the plurality of implant segments, a posterior surface of the segment base portion is recessed inwardly from a posterior-most portion of a first closed loop and is recessed inwardly from the posterior-most portion of the second closed loop.

19. The disc nucleus replacement system of claim 16, wherein, with respect to each of the plurality of implant segments, the segment base portion or rigid extension thereof extends anteriorly to define or to abut an anterior-most portion of the implant segment.

20. The disc nucleus replacement system of claim 17, wherein, with respect to each of the plurality of implant segments, the first outer wall and second outer wall curve toward each other at an anterior end of the implant segment such that an anterior end of the first outer wall and an anterior end of the second outer wall confront each other with a gap therebetween.

21. The disc nucleus replacement system of claim 20, wherein, with respect to each of the plurality of intermediate implant segments, the anterior end portion of each of the first lobe and the second lobe are contractible such that the anterior end of the first outer wall and the anterior end of the second outer wall are movable toward each other.

22. The disc nucleus replacement system of claim 21, wherein, with respect to each of the plurality of intermediate implant segments, an internal web extends between the first lobe and the second lobe such that when a center portion of the web is translated anteriorly the web pulls the first lobe toward the second lobe.

23. The disc nucleus replacement system of claim 22, further comprising an elongate implant tool, wherein, with respect to each of the plurality of intermediate implant segments, the implant tool extends through the segment base portion by way of the implant tool interface and is movable axially within the implant segment to engage and translate the center portion of the web anteriorly causing the first lobe and second lobe to move toward each other.

24. The disc nucleus replacement system of claim 23, wherein, with respect to each of the plurality of intermediate implant segments, the webbing extends between the first outer wall and the second outer wall and is positioned in an anterior half portion of the implant segment.Attorney Docket No. 5364.002W0125. The disc nucleus replacement system of claim 24, wherein, with respect to each of the plurality of intermediate implant segments, the webbing has an anteriorly positioned engagement portion that engages the anterior ends of the first outer wall and the second outer wall when it is translated anteriorly.

26. The disc nucleus replacement system of claim 23, wherein, with respect to each of the plurality of intermediate implant segments, the posterior ends of the first outer wall and second outer wall are each connected to the posterior end of the segment base portion and extend posteriorly therefrom.

27. The disc nucleus replacement system of claim 26, wherein, with respect to each of the plurality of intermediate implant segments, an anterior surface of the segment base portion is recessed inwardly from the anterior-most portion of the first outer wall and is recessed inwardly from the anterior-most portion of the second outer wall.

28. The disc nucleus replacement system of claim 27, wherein, with respect to each of the plurality of intermediate implant segments, the posterior ends of the first outer wall and second outer wall are each separate and spaced from the posterior end of the segment base portion.

29. The disc nucleus replacement system of claim 13, wherein, with respect to each of the plurality of intermediate implant segments, the first outer wall is connected to the segment base portion exclusively by the first elastomeric insert and the second outer wall is connected to the segment base portion exclusively by the second elastomeric insert.

30. The disc nucleus replacement system of claim 29, wherein, with respect to each of the plurality of intermediate implant segments, the first elastomeric insert provides a fulcrum with respect to the first outer wall such that when the posterior end of the first outer wall is moved in a superior direction, the anterior end of the first outer wall moves in an inferior direction, and wherein the second elastomeric insert provides a fulcrum with respect to the second outer wall such that when the posterior end of the second outer wall moves in an inferior direction, the anterior end of the second outer wall moves in an inferior direction.

31. The disc nucleus replacement system of claim 30, further comprising an elongate implant tool, and wherein, with respect to each of the plurality of intermediate implant segments, a forward end of the elongate implant tool engages with the segment base portion by insertion into an opening at the implant tool interface, and wherein the elongate implant tool is movable anteriorly with respect to the segment base portion, and wherein the implant tool has a wedge portion spaced from the forward end positioned to engage the posterior ends of the first outer wall and second outer wall to cause the ends to separate as the implant tool movesAttorney Docket No. 5364.002W01anteriorly thereby causing the anterior ends of the first outer wall and second outer wall to contract towards each other.

32. The disc nucleus replacement system of claim 13, wherein the disc nucleus replacement system is for a lordotic segment of the spine of the patient, and when viewed laterally, each of the plurality of intermediate implant segments have an ovate shape with a maximum superior¬ inferior thickness at an anterior half portion of each of the respective intermediate implant segments, and wherein the first outer wall and second outer wall curve toward each other at an anterior end of the implant segment such that an anterior end of the first outer wall and an anterior end of the second outer wall each have cam follower surfaces thereon and confront each other with a gap therebetween.

33. The disc nucleus replacement system of claim 32, further comprising an elongate implant tool with converging cam surfaces on a forward end, the implant tool insertable through the segment base portion to engage the cam follower surfaces on the anterior ends of the first and second outer walls.that is engageable with the joint cam follower surfaces on each of the anterior ends of the first and second outer walls for moving the anterior ends inwardly toward each other and thereby contracting the anterior end of the implant segment.

34. The disc nucleus replacement system of claim 4, wherein the disc nucleus replacement system is for a lordotic segment of the spine of the patient, and when viewed laterally, each of the plurality of intermediate implant segments have an ovate shape with a maximum superior-inferior thickness at an anterior half portion of each of the respective implant segments, and wherein for when the access port height is less than the maximum superior-inferior thickness, the anterior half portion is deflectable to be equal to or to be less than the access port height.

35. The disc nucleus replacement system of claim 4, wherein the disc nucleus replacement system is for a lordotic segment of the spine of the patient, and when viewed laterally, each of the plurality of intermediate implant segments have an ovate shape with a maximum superiorinferior thickness at an anterior half portion of each of the respective implant segments, and wherein where the access port height is less than the maximum superior-inferior thickness, the anterior half portion is deflectable to contract at least 2 mm.

36. The disc nucleus replacement system of claim 34, wherein, with respect to each of the plurality of intermediate implant segments, the anterior half portion may be contracted before or during passing through the access port by utilizing a cam tool cooperating with cam surfaces on the implant segment.Attorney Docket No. 5364.002W0137. The disc nucleus replacement system of claim 34, wherein, with respect to each of the plurality of intermediate implant segments, the first resilient compressible spring component comprises a first elastomeric insert, and wherein the second resilient compressible spring component comprises a second elastomeric insert and wherein the first elastomeric insert is unitary with and connected to the second elastomeric insert by elastomeric material extending therebetween.

38. The disc nucleus replacement system of claim 37, wherein, with respect to each of the plurality of intermediate implant segments, the first elastomeric insert is unitary with and connected to the second elastomeric insert by a bridging portion extending through a superior-inferior extending aperture in the segment base portion.

39. The disc nucleus replacement system of claim 37, wherein, with respect to each of the plurality of intermediate implant segments, each of the elastomeric inserts have at least one void passing laterally through the elastomeric insert.

40. The disc nucleus replacement system of claim 34, wherein, with respect to each of the plurality of intermediate implant segments, the anterior half portion may be contracted before passing through the access port by utilizing a restraint between the first spring lobe and the second spring lobe to pull the first spring lobe and second spring lobe together reducing the maximum superior-inferior thickness of the anterior half portion, the restraint releasable after the respective spring lobe is in the evacuated nucleus space.

41. The disc nucleus replacement system of claim 40, wherein, with respect to each of the plurality of intermediate implant segments, the restraint is formed of a material that dissolves when in contact with bodily fluids.

42. The disc nucleus replacement system of claim 34, further comprising a restraint that may be applied between the first lobe and second lobe of the implant segments before insertion through the access port to pull the first lobe toward the second lobe.

43. The disc nucleus replacement system of claim 42, wherein the restraint is a dissolvable suture, string, strip, or clamp.

44. The disc nucleus replacement system of claim 34, further comprising an implant tool that may be applied through the segment base portion before insertion of the implant segment through the access port to retain the first lobe and the second lobe in a contracted position.

45. The disc nucleus replacement system of claim 3, wherein the disc nucleus replacement system is for a lordotic segment of the spine of the patient, and when viewed laterally, each of the plurality of intermediate implant segments have an ovate shape with a maximum Superior-Attorney Docket No. 5364.002W01inferior thickness at an anterior half portion of each of the respective intermediate implant segments.

46. The disc nucleus replacement system of claim 4, wherein the disc nucleus replacement system is for a lordotic segment of the spine of the patient, and when viewed laterally, each of the plurality of intermediate implant segments have an ovate shape with a maximum superior-inferior thickness at an anterior half portion of each of the respective intermediate implant segments.

47. The disc nucleus replacement system of claim 2, wherein the disc nucleus replacement system is for a lordotic segment of the spine of the patient, and when viewed laterally, each of the plurality of intermediate implant segments have an ovate shape with a maximum superiorinferior thickness at an anterior half portion of each of the respective intermediate implant segments.

48. The disc nucleus replacement system of claim 47, wherein, with respect to each of the plurality of intermediate implant segments, the first spring lobe comprises a first elastomeric spring element, the elastomeric spring element engaged and connected with the segment base portion, and wherein the second spring lobe comprises a second elastomeric spring element engaged and connected with the segment base portion.

49. The disc nucleus replacement system of claim 48, wherein, with respect to each of the plurality of intermediate implant segments, the first elastomeric spring element defines the first smooth convex exterior C-shaped surface, and the second elastomeric spring element defines the second smooth convex exterior C-shaped surface.

50. The disc nucleus replacement system of claim 49, wherein, with respect to each of the plurality of intermediate implant segments, the first elastomeric spring element is unitary and connected to the second elastomeric spring element.

51. The disc nucleus replacement system of claim 50, wherein, with respect to each of the plurality of intermediate implant segments, the first elastomeric spring element is unitary and connected to the second elastomeric spring element by a bridging portion extending through an aperture in the segment base portion.

52. The disc nucleus replacement system of claim 48, wherein, with respect to each of the plurality of intermediate implant segments, the first elastomeric spring element and second elastomeric spring element each have a plurality of elongate windows that define a plurality of pillars extending superiorly and inferiorly from the implant base portion.

53. The disc nucleus replacement system of claim 1, wherein, with respect to each of the plurality of intermediate implant segments, the segment base portion has on one lateral side anAttorney Docket No. 5364.002W01elongate male rail extending at least most of the anterior posterior length of the base portion, and having an axis, the segment base portion having on an opposite lateral side, within a body of the segment base portion, a cooperating elongate slot for receiving such a male rail in a previously inserted implant segment.

54. The disc nucleus replacement system of claim 53, wherein, with respect to each of the plurality of intermediate implant segments, the elongate male rail has a T-shape when viewed posteriorly or anteriorly with a planar outer surface in the sagittal plane, the rail having a cantilevered portion at an anterior end portion of the rail, the cantilevered portion of the rail having a detent projecting thereon to mate with a cooperating detent recess in a cooperating elongate slot.

55. The disc nucleus replacement system of claim 53, wherein, the anterior portion of each of the intermediate implant segments have an enlarged opening with lead in surfaces for the slot receiving the elongate male rail to facilitate connection of the inserted implant segments.

56. The disc nucleus replacement system of claim 55, wherein, with respect to each of the plurality of intermediate implant segments, when view in a superior or inferior direction the anterior end has a taper on the lateral side with the receiving slot for the elongate male rail.

57. An implant segment for insertion and assembly into a nucleus pulposis prosthesis with a plurality of other inserted implant segments into a lordotic segment of a spine of a patient, the implant segment inserted through an anterior access port defined in part by the superiorinferior gap between the posterior corners of adjacent vertebral plates, wherein the implant segment comprises:a rigid segment base portion having two lateral sides, an anterior side, a posterior side, a superior side, and an inferior side, the base portion having an insertion tool interface at the posterior side at an anterior-posterior opening, the opening sized to receive the insertion tool;a first resilient spring component compressible and reboundable in the inferior-superior direction and secured to the segment base portion at the superior side;a second resilient spring component compressible and reboundable in the superiorinferior direction and secured to the segment base portion at the superior side;wherein the implant segment has an uncompressed superior-inferior maximum thickness greater than the superior-inferior gap;wherein the implant segment has a means for contraction of the implant for facilitating insertion through the access port without removing spinous material from the adjacent vertebral plates.Attorney Docket No. 5364.002W0158. The implant segment of claim 57, wherein the implant segment, when viewed laterally has an ovate shape.

59. The implant segment of claim 57, wherein the segment, when viewed laterally, the anterior half portion has greatest height.

60. The implant segment of claim 57, wherein the means for contraction of the superior-inferior thickness to allow insertion61. The implant segment of claim 57, wherein when viewed laterally, an anterior end is wedge shaped.

62. The implant segment of claim 57, wherein the means for contraction of the superior-inferior thickness to allow insertion comprises cam follower surfaces that engage with cam surfaces on an insertion tool.

63. The implant segment of claim 57, in combination with the insertion tool.

64. An implant segment for insertion and assembly into a nucleus pulposis prosthesis with a plurality of other inserted implant segments into a lordotic segment of a spine of a patient, the implant segment inserted through an anterior access port defined in part by the superior-inferior gap between the posterior corners of adjacent vertebral plates, wherein the implant segment comprises:a rigid segment base portion having two lateral sides, an anterior side, a posterior side, a superior side, and an inferior side, the base portion having an insertion tool interface at the posterior side at an anterior-posterior opening, the opening sized to receive the insertion tool;a first resilient spring component compressible and reboundable in the inferior-superior direction and secured to the segment base portion at the superior side;a second resilient spring component compressible and reboundable in the superiorinferior direction and secured to the segment base portion at the superior side;wherein the implant segment has an uncompressed superior-inferior maximum thickness greater than the superior-inferior gap;wherein the implant segment has a means for withstanding shocks during insertion through the access port.

65. The implant segment of claim 64, wherein the means for withstanding shocks during insertion comprises an extension of the rigid base portion that extends to the most anterior portion of the segment.

66. An implant segment for insertion and assembly into a nucleus pulposis prosthesis with a plurality of other inserted implant segments into a lordotic segment of a spine of a patient, the implant segment inserted through an anterior access port defined in part by the Superior-Attorney Docket No. 5364.002W01inferior gap between the posterior corners of adjacent vertebral plates, wherein the implant segment comprises:a rigid segment base portion having two lateral sides, an anterior side, a posterior side, a superior side, and an inferior side, the base portion having an insertion tool interface at the posterior side at an anterior-posterior opening, the opening sized to receive the insertion tool;a first resilient spring component compressible and reboundable in the inferior-superior direction and secured to the segment base portion at the superior side;a second resilient spring component compressible and reboundable in the superior¬ inferior direction and secured to the segment base portion at the superior side;wherein the implant segment has a means for facilitating connection with a previously inserted implant segment within the evacuated nucleaus space.

67. The implant segment of claim 66, wherein the mean comprises a bevel at the anterior corner of the implant segment when view superiorly.

68. The implant segment included in any of the above claims wherein the interior of the C-shaped wall faces towards the implant base portion.

69. The implant segment included in any of the above claims wherein the elastomeric spring component is overmolded onto the C-shaped wall.

70. The implant segment included in any of the above claims wherein the elastomeric spring component is overmolded onto the implant base portion71. The implant segment included in any of the above claims, wherein the base portion does not provide any compression and resilient rebound under loading in the nucleus pulposis.

72. The implant segment included in any of the above claims, wherein there are a plurality of voids intermediate the C-shaped outer surface and the segment base portion, wherein the plurality of voids are spaced from the c-shaped outer surface and the segment base portion 73. The implant segment included in any of the above claims, wherein each of the C-shaped outer walls comprises titanium74. The implant segment included in any of the above claims, wherein each of the C-shaped outer walls comprises PEEK75. The implant segment included in any of the above claims, wherein each of the cantilevered fingers and the finger base unitary and homogeneous with the plurality of cantilevered fingers comprise titanium76. The implant segment included in any of the above claims, wherein each of the cantilevered fingers and the finger base unitary and homogeneous with the plurality of cantilevered fingers comprise PEEKAttorney Docket No. 5364.002W0177. The implant segment included in any of the above claims, wherein the spring unit comprising cantilevered fingers and the finger base are welded to the base portion.

78. The implant segment included in any of the above claims, wherein the posterior side of the segment base portion has two tool interfaces configured as a first hold and a second hole extending into and / or through the segment base portion, each hole having an axis parallel to each other and extending in the anterior-superior direction.

79. The implant segment included in any of the above claims, wherein one is a threaded hole and die other is a non threaded hole80. The implant segment included in any of the above claims, wherein one of the first hole and second hole extends into or through a body of the segment base portion and the other of the first and second hole extends into or through an elongate male adjacent segment connector.

81. A method of manufacturing an implant segment of a modular implantable nucleus prosthesis, the method comprising the steps of:forming a skeletal preform of a rigid polymer having a Youngs Modulus of greater than 3.0 GPa, the preform comprising:a base portion with an interface on a lateral side of the base portion for connection to another implant segment of the modular implantable nucleus prosthesis, the preform having a first exterior wall with a convex exterior surface for engaging a vertebral plate in an evacuated nucleus space:a superior outer wall having convex smooth curvature and a smooth surface; an inferior outer wall having convex smooth surface with a smooth curvature; wherein a first spring space is defined between the base portion and one of the superior outer wall and the inferior outer wall;the method further comprising disposing a first spring insert in the superior spring space and inserting an inferior spring insert into the one of the superior outer wall and the inferior outer wall.

82. The method of claim 81, wherein forming the skeletal preform further includes defining a second spring space between the base portion and the other of the superior outer wall and the inferior outer wall, and the method further comprises disposing a second spring insert in the other of the superior outer wall and the inferior outer wall.

83. The method of claim 82, further comprising forming the skeletal preform by injection molding.

84. The method of claim 81, further comprising injection molding the first spring insert out of a rigid polymer with a plurality of spring members.Attorney Docket No. 5364.002W0185. The method of claim 81, further comprising injection molding the first spring insert out of a rigid polymer with a plurality of cantilevered spring members extending from a spring base.

86. The method of claim 81, wherein forming the skeletal preform further includes defining a second spring space between the base portion and the other of the superior outer wall and the inferior outer wall, and the method further comprises disposing a second spring insert in the second spring space and wherein the method further comprises molding the second spring insert out of a rigid polymer to define a plurality of spring members.

87. The method of claim 86 further comprising connecting the first spring insert to the preform by welding and connecting the second spring insert to the preform by welding.

88. The method of claim 81, wherein the step of disposing a first spring insert in the first spring space comprises overmolding a thermoplastic elastomer into tire first spring space, the molded thermoplastic elastomer defining the first spring space.

89. The method of claim 88, further comprising interlocking the elastomeric first spring to the skeletal preform utilizing cooperating interlocking structure on the skeletal structure that the thermoplastic elastomer captures.

90. The method of claim 88, further comprising providing voids in the molded thermoplastic elastomer.

91. The method of claim 82, wherein the step of disposing a first spring insert in the first spring space comprises overmolding a thermoplastic elastomer into tire first spring space, the molded thermoplastic elastomer defining the first spring space and the step of disposing a second spring insert in the second spring space comprises overmolding the thermoplastic elastomer into the second spring space.

92. The method of claim 88, further comprising interlocking the elastomeric first spring to the skeletal preform during the overmolding by utilizing cooperating interlocking structure on the skeletal structure that the elastomer captures and interlocking the elastomeric second spring to the skeletal preform during tire overmolding utilizing cooperating interlocking structure on the skeletal structure that the elastomer captures.

93. The method of claim 91, wherein the thermoplastic elastomer of the first spring insert is connected to and homogeneous the second spring insert by way of a bridge structure extending therebetween and formed during the overmolding.

94. The method of any one of claims 81-93, wherein injection molding the skeletal preform includes molding the first outer wall with an arcuate shape having two opposing ends and having the entirety of the first outer wall being a separate part distinct from the base portion.Attorney Docket No. 5364.002W01

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