Patent ID: 12257160

DETAILED DESCRIPTION

Exemplary embodiments of the technology will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. It will be readily understood that the components of the technology, as generally described and illustrated in the figures herein, could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of the embodiments of the apparatus, system, and method is not intended to limit the scope of the invention, as claimed, but is merely representative of exemplary embodiments of the technology.

The phrases “connected to,” “coupled to” and “in communication with” refer to any form of interaction between two or more entities, including mechanical, electrical, magnetic, electromagnetic, fluid, and thermal interaction. Two components may be functionally coupled to each other even though they are not in direct contact with each other. The term “abutting” refers to items that are in direct physical contact with each other, although the items may not necessarily be attached together. The phrase “fluid communication” refers to two features that are connected such that a fluid within one feature is able to pass into the other feature.

The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments. While the various aspects of the embodiments are presented in drawings, the drawings are not necessarily drawn to scale unless specifically indicated.

Standard medical planes of reference and descriptive terminology are employed in this specification. While these terms are commonly used to refer to the human body, certain terms are applicable to physical objects in general.

A standard system of three mutually perpendicular reference planes is employed. A sagittal plane divides a body into right and left portions. A coronal plane divides a body into anterior and posterior portions. A transverse plane divides a body into superior and inferior portions. A mid-sagittal, mid-coronal, or mid-transverse plane divides a body into equal portions, which may be bilaterally symmetric. The intersection of the sagittal and coronal planes defines a superior-inferior or cephalad-caudal axis. The intersection of the sagittal and transverse planes defines an anterior-posterior axis. The intersection of the coronal and transverse planes defines a medial-lateral axis. The superior-inferior or cephalad-caudal axis, the anterior-posterior axis, and the medial-lateral axis are mutually perpendicular.

Anterior means toward the front of a body. Posterior means toward the back of a body. Superior or cephalad means toward the head. Inferior or caudal means toward the feet or tail. Medial means toward the midline of a body, particularly toward a plane of bilateral symmetry of the body. Lateral means away from the midline of a body or away from a plane of bilateral symmetry of the body. Axial means toward a central axis of a body. Abaxial means away from a central axis of a body. Ipsilateral means on the same side of the body. Contralateral means on the opposite side of the body. Proximal means toward the trunk of the body. Proximal may also mean toward a user or operator. Distal means away from the trunk. Distal may also mean away from a user or operator. Dorsal means toward the top of the foot. Plantar means toward the sole of the foot. Varus means deviation of the distal part of the leg below the knee inward, resulting in a bowlegged appearance. Valgus means deviation of the distal part of the leg below the knee outward, resulting in a knock-kneed appearance.

In this specification, standard spine anatomical and directional terms are employed with their ordinary and customary meanings.

In this specification, “substantially” means within ±10%.

Referring toFIGS.1-7, an intervertebral spacer implant system100may include a solid body200, a porous body300, a bone anchor such as a bone screw400, and/or a locking mechanism such as a locking screw500. Preferably, the solid body200and the porous body300may be integrally formed together as a single part, such as by an additive manufacturing process. For the purposes of description, however, the solid body200and the porous body300will be described and shown as if they are separate parts. The example shows a superior bone screw402and an inferior bone screw404. The bone screws may be replaced by other types of bone anchors. The system100has a leading side102and a trailing side104. In this embodiment, the leading side102may be a posterior side and the trailing side104may be an anterior side so that the system100is adapted for an anterior approach to the spine. The system100includes a first side106that may be considered the top or superior aspect of the system100and a second side108that may be considered the bottom or inferior aspect of the system100; however, the top and bottom may also be interchangeable. The first and second sides106,108may be referred to as bone-facing sides of the system100. The system100has a right side110and a left side112; however, the left and right sides may also be interchangeable. There may be an aperture114in the right side110and an aperture116in the left side112that may also be interchangeable.

FIGS.3-7show the placement and proximity of the components of the system100; the solid body200, the porous body300, the superior bone screw402, the inferior bone screw404, and the locking screw500that fixes the bone screws402,404in position relative to the solid body200and the porous body after screw insertion.

Referring toFIGS.8-15, the solid body200has a leading side201and a trailing side202. In this embodiment, the leading side201may be a posterior side and the trailing side202may be an anterior side. The solid body200has a first side203that may be considered the top or superior aspect of the solid body200and a second side204that may be considered the bottom or inferior aspect of the solid body200; however, the top and bottom may also be interchangeable. The second side204may be identical to the first side203as shown, or a mirror image. The solid body200has a right side206and a left side208; however, the left and right sides may also be interchangeable. The left side208may be a mirror image of the right side206as shown. A perimeter wall207may extend around the solid body200between the first and second sides203,204, and may include the leading side201, the trailing side202, the right side206, and the left side208. There may be an aperture226in the right side206and an aperture228in the left side208that may also be interchangeable. The left aperture228may be a mirror image of the right aperture226as shown.

FIG.8is an oblique view showing the trailing side202, the first side203, and the left side208of the solid body200. The first side203has a perimeter that may have one or more projections230, such as teeth, serrations, denticles, spikes, prongs, etc. along the left and right portions of the first side203. The projections230extend outwardly from the first side203and may be inclined toward the trailing side202(FIG.13). One or more taller projections231may also be present on the first side203. A single projection231is shown at the left trailing corner of the first side203, having a triangular profile (FIG.12). The first side203also includes an asymmetrical overhang or lobe210that may also be referred to as a platform, collar, flange, washer, etc. This lobe210is adjacent to the trailing side202and also adjacent to the right side206. In other words, the lobe210extends from the right trailing portion of the first side203toward a central region of the first side203. The lobe210overhangs a central cavity205within the solid body200. The lobe210may be cantilevered over the central cavity205. The lobe210provides support around the right bore220that receives the superior bone screw402, and acts as a washer for the bone screw402, providing increased surface area for vertebral bone contact. Referring toFIGS.13and15, the lobe210may protrude outwardly beyond the height of the perimeter wall207so that the lobe is elevated above the nominal height of the perimeter wall to make firm contact with the adjacent vertebral endplate. More than one lobe210may be present on the first side203. The superior lobe210is shown with three apertures: a right aperture212that may be triangular in shape, a middle aperture214that may be trapezoidal in shape, and a left aperture216that may be rectangular in shape. Any number of apertures may be included, and the apertures may have any shape. The apertures may accommodate the prominences of the porous body300, discussed below.FIG.8shows a right bore220for the superior bone screw402that extends into the vertebra above the system100and a left bore222for the inferior bone screw404that extends into the vertebra below the system100. Referring toFIGS.10and12, the right bore220extends through the trailing side202and the first side203along an oblique trajectory from anterior-inferior-lateral to posterior-superior-medial, and the left bore222extends through the trailing side202and the second side204along another oblique trajectory from anterior-superior-lateral to posterior-inferior-medial. The bores220,222may be partially or entirely surrounded by cylindrical walls that extend along the oblique trajectories between the trailing side202and the first side203and lobe210(for bore222) or between the trailing side202and the second side204and lobe232(for bore220). SeeFIGS.10and12. Advantageously, a full-length, full-diameter cylindrical wall stabilizes the bone screws402,404to minimize or eliminate the screw from wobbling. The bores220,222may include features that interact with the bone screws402,404to provide polyaxial angulation of the screws and/or to lock the screws to the solid body200and/or the porous body300. A centralized bore221may extend through the trailing side202between the left and right bores220,222along a trailing-leading direction. The centralized bore221may be internally threaded. A sunken region223may surround the centralized bore221.

FIG.9is another oblique view of the solid body ofFIG.8showing the leading side201, the second side204, and the right side206. The first side203of the solid body200(FIG.8) and the second side204of the solid body200(FIG.9) may be identical, interchangeable, or mirror images of each other. An inferior lobe232is shown on the second side204extending from the left trailing portion of the second side toward a central region of the second side204. The inferior lobe232may be identical to the superior lobe210, interchangeable, or mirror images. This view shows a supporting structure224around the centralized bore221that receives the locking screw500. The supporting structure224projects from the trailing side202into the central cavity205along the trailing-leading direction, and may taper down in height along the trailing-leading direction.

FIGS.10-15show the placement of the features of the solid body200in relation to the leading side201and the trailing side202; the location of the projections230,231on the perimeters of the first and second sides203,204, the superior lobe210, the inferior lobe232, the lobal apertures212,214,216, the right bore220, the left bore222, and the centralized bore221.FIG.15is a cross-sectional view along section line15-15ofFIG.12, showing the depth of the centralized bore221that accepts the locking screw500and the surrounding supporting structure224.

Referring toFIGS.16-23, the porous body300has a leading side301and a trailing side302. In this embodiment, the leading side301may be a posterior side and the trailing side302may be an anterior side. The porous body300has a first side303that may be considered the top or superior aspect of the porous body300and a second side304that may be considered the bottom or inferior aspect of the porous body300; however, the top and bottom may also be interchangeable. The second side304may be identical to the first side303, or a mirror image. The porous body300has a right side306and a left side308; however, the left and right sides may also be interchangeable. The left side308may be a mirror image of the right side306as shown.

FIG.16is an oblique view of the porous body300showing the trailing side302, the first side303, and the left side308. The trailing side302includes a right bore320that surrounds the right bore220of the solid body200, and a left bore322that surrounds the left bore222of the solid body200. The trailing side302also includes a centralized bore324that surrounds the centralized bore221of the solid body200. The centralized bore324may be sized and shaped to receive the supporting structure224of the solid body. Alternatively, at least for embodiments that are fabricated by additive manufacturing operations, the bore324may have an inside diameter that is larger than the major diameter of the internal threads of the bore221, as shown. The first side303of the porous body300features a superior porous structure310with three raised prominences of porous material: a superior right prominence312which may be triangular in shape, a superior middle prominence314which may be trapezoidal in shape, and a superior left prominence316which may be rectangular in shape. Any number of prominences may be included, and the prominences may have any shape. Preferably, the number and shape of the prominences corresponds to the number and shape of the lobal apertures of the solid body200. Referring toFIGS.20-23, each prominence may include a domed or bulging superior surface to enhance contact with the adjacent vertebral endplate. The superior porous structure310may include a pedestal311that extends internally from the first side303. The pedestal may taper toward the trailing side302as it extends. The first side303of the porous body300and the second side304of the porous body300are interchangeable.

FIG.17is another oblique view of the porous body ofFIG.16showing the leading side301, the second side304, and the right side306. The porous body300includes an inferior porous structure318which may be identical to the superior porous structure310as shown, interchangeable, or mirror images. The first side303of the porous body300is a mirror image of the second side304of the porous body304and may be interchangeable.

FIGS.18-23show the structure of the porous body300indicating the placement of the superior porous structure310and the inferior porous structure318. The second side304is the mirror image of the first side303.FIG.21depicts the mounding on top of the superior and inferior prominences312,314,316. The porous prominences on both the first side303and the second side304are seated within the lobal apertures of the solid body200in such a way that the mounds on top of the prominences may extend above, or outward from, the surfaces of the lobes of the solid body200. This extension allows the vertebral bone to contact the porous body first under compression to promote bone growth into the porous material.FIG.23is a cross-sectional view ofFIG.20along section line23-23that shows the centralized bore324.

Referring toFIG.24, a bone screw400has a head406that contains a drive feature408to receive torque from a screw driver (not shown). Below the head406is a smooth shank407or shaft. Below the smooth shank is a threaded shank410or shaft that may have a tapered end412and may have a self-tapping feature414that allows the screw400to be driven into the vertebral bone without pre-drilling. The inferior bone screw404may be identical to the superior bone screw402.

Referring toFIGS.7and25, the locking screw500has a head502that contains a drive feature504to receive torque from a screw driver (not shown). Below the head502is a smooth shank505or shaft. Below the smooth shank is a threaded shank506or shaft that may have a tapered end508. The head502of the locking screw500has a rounded or tapered edge510to reduce contact with or injury to vertebral or neurovascular structures.

The solid body200and the porous body300may be fabricated together at the same time via additive manufacturing technology. Thus, the disclosed solid body200and porous body300may be superimposed or “occupy the same space.” The solid body200may be fully dense or non-porous, or it may be distinctly more dense or less porous than the porous body300. The solid body200may be 80% to 100% dense. The porous body300may be 80%±10% dense or 80%±5% dense. The porous body300may have one or more pore sizes and/or shapes which are favorable for bone ongrowth/ingrowth. The porous body300may have a consistent porous structure throughout, or there may be one or more gradients or abrupt changes in porous structure. The porous body300may provide sufficient internal support structure to the solid body lobes so that no additional temporary support structure is required to ensure that the solid body builds according to specifications. Preferably, the taper angles of the pedestals311of the porous body300may be selected to be compatible with the taper angles that a given additive manufacturing system will build without additional temporary support structure and with satisfactory finished product. Preferably, the taper angles of the pedestals311of the porous body300may be 45° or less. In one example, the solid body200and the porous body300may be fabricated together by additive manufacturing with the solid and porous bodies200,300superimposed and oriented so that the leading side201is the base on which the bodies are built or printed, in other words, the first layer of the build, and the trailing side202includes the last layer of the build. In another example, the trailing side202includes the first layer of the build and the leading side201includes the last layer of the build.

The centralized bore324of the porous body surrounds the centralized bore221of the solid body, and may optionally receive the supporting structure224. The right bore320surrounds the right bore220. The left bore322surrounds the left bore222. The superior porous structure310supports the superior lobe210. The inferior porous structure318supports the inferior lobe232. The porous prominences312,314,316may extend outwardly through the apertures212,214,216, respectively, as shown. Alternatively, the solid structure of the lobes210,232may extend outwardly past the porous structures310,318and corresponding prominences312,314,316. The porous body300may fill only a portion of the central cavity205of the solid body, so that a portion of the cavity205remains empty to receive bone graft or other therapeutic agents. Preferably, the empty portion of the cavity205extends through the interconnected solid and porous bodies200,300along a superior-inferior direction. The porous body300, or at least the superior and inferior porous structures310,318, may be flexible enough to permit the lobes210,232to flex inwardly toward a central transverse plane of the implant under compressive loads applied by adjacent superior and inferior vertebrae. The central transverse plane of the implant is represented by section line11-11ofFIG.12and section line19-19ofFIG.20. The central sagittal plane of the implant is represented by section lines7-7ofFIG.4,15-15ofFIG.12, and23-23ofFIG.20.

A method of implanting the intervertebral spacer may include some or all of the following steps in any order: creating a surgical access to an operative site, removing a disc from between adjacent superior and inferior vertebrae, inserting the solid/porous spacer along a trailing-leading direction into the prepared disc space, optionally drilling for the bone screw(s), inserting the bone screws through the bores220,222and into the vertebral bodies, and after the bone screws are fully inserted, inserting the locking screw into the bore221along the trailing-leading direction, and closing the surgical access.

Referring toFIGS.26-32, an intervertebral spacer implant system1100may include a solid body1200, a porous body1300, a bone anchor such as the bone screw404or a helical blade1450, and/or a locking mechanism, such as a bushing1500and/or a collar1550. Preferably, the solid body1200and the porous body1300may be integrally formed together as a single part, such as by an additive manufacturing process. For the purposes of description, however, the solid body1200and the porous body1300will be described and shown as if they are separate parts. The example shows a superior helical blade1450and an inferior bone screw404. The bone anchors may be interchangeable, or they may be replaced by other types of bone fasteners. The system1100has a leading side1102and a trailing side1104. In this embodiment, the leading side1102may be a posterior side and the trailing side1104may be an anterior side so that the system1100is adapted for an anterior approach to the spine. The system1100includes a first side1106that may be considered the top or superior aspect of the system1100and a second side1108that may be considered the bottom or inferior aspect of the system1100; however, the top and bottom may also be interchangeable. The first and second sides1106,1108may be referred to as bone-facing sides of the system1100. The system1100has a right side1110and a left side112; however, the left and right sides may also be interchangeable. There may be an aperture1114in the right side1110and an aperture1116in the left side1112that may also be interchangeable.

FIGS.28-32show the placement and proximity of the components of the system1100; the solid body1200, the porous body1300, the superior helical blade1450, the inferior bone screw404, the bushing1500, and the collar1550.

Referring toFIGS.33-40, the solid body1200has a leading side1202and a trailing side1204. In this embodiment, the leading side1202may be a posterior side and the trailing side1204may be an anterior side. The solid body1200has a first side1206that may be considered the top or superior aspect of the solid body1200and a second side1208that may be considered the bottom or inferior aspect of the solid body1200; however, the top and bottom may also be interchangeable. The second side1208may be identical to the first side1206as shown, or a mirror image. The solid body1200has a right side1210and a left side1212; however, the left and right sides may also be interchangeable. The left side1212may be a mirror image of the right side1210as shown. A perimeter wall1218may extend around the solid body1200between the first and second sides1206,1208, and may include the leading side1202, the trailing side1204, the right side1210, and the left side1212. There may be an aperture1214in the right side1210and an aperture1216in the left side1212that may also be interchangeable. The left aperture1216may be a mirror image of the right aperture1214as shown.

FIG.33is an oblique view showing the trailing side1204, the first side1206, and the left side1212of the solid body1200. The first side1206has a perimeter that may have one or more projections1220, such as teeth, serrations, denticles, spikes, prongs, etc. along the left and right portions of the first side1206. The projections1220extend outwardly from the first side1206and may be inclined toward the trailing side1204(FIG.38). One or more taller projections1222may also be present on the first side1206. Projections1222are shown at the trailing edge near the right trailing corner and at the left trailing corner of the first side1206, having a triangular profile (FIG.37). The first side1206also includes an asymmetrical overhang or lobe1224that may also be referred to as a platform, collar, flange, washer, etc. This lobe1224is adjacent to the trailing side1204and also adjacent to the right side1210. In other words, the lobe1224extends from the right trailing portion of the first side1206toward a central region of the first side1206. The lobe1224overhangs a central cavity1226within the solid body1200. The lobe1224may be cantilevered over the cavity1226. The lobe1224provides support around the right bore1228that receives the superior helical blade1450, and acts as a washer for the helical blade1450, providing increased surface area for vertebral bone contact. Referring toFIGS.38and40, the lobe1224may protrude outwardly beyond the height of the perimeter wall1218so that the lobe is elevated above the nominal height of the perimeter wall to make firm contact with the adjacent vertebral endplate. More than one lobe1224may be present on the first side1206. The superior lobe1224is shown with an aperture1230that may be rectangular in shape and may be centrally located between the right and left sides1210,1212. Any number of apertures may be included, and the apertures may have any shape. The aperture(s) may accommodate the prominences of the porous body1300, discussed below. The superior lobe1224may include one or more sunken regions, such as the sunken region1232associated with the aperture1230and/or the sunken region1234to the right of the right bore1228. However, a wall1236may remain at the full height of the lobe1224, encircling the right bore1228; another wall1238may remain at the full height of the lobe, extending along the left and leading sides of the lobe.FIG.33shows a right bore1228for the superior helical blade1450that extends into the vertebra above the system1100and a left bore1240for the inferior bone screw404that extends into the vertebra below the system1100. Referring toFIGS.35and37, the right bore1228extends through the trailing side1204and the first side1206along an oblique trajectory from anterior-inferior-lateral to posterior-superior-medial, and the left bore1240extends through the trailing side1204and the second side1208along another oblique trajectory from anterior-superior-lateral to posterior-inferior-medial. The bores1228,1240may be partially or completely surrounded by cylindrical walls that extend along the oblique trajectories between the trailing side1204and the first side1206and lobe1224(for bore1240) or between the trailing side1204and the second side1208and lobe1242(for bore1228). Advantageously, a full-length, full-diameter cylindrical wall stabilizes the bone anchors1450,404to minimize or eliminate the fasteners from wobbling. The bores1228,1240may include features that interact with the bone anchors1450,404to provide polyaxial angulation of the fasteners and/or to lock the fasteners to the solid body1200and/or the porous body1300. A centralized bore1244may extend through the trailing side1204between the left and right bores1228,1240along a trailing-leading direction. The centralized bore1244may be internally threaded. A counterbore1246may be associated with the centralized bore1244; the counterbore1246may be internally threaded to receive the bushing1500. A sunken region1248may surround the centralized bore1244and/or counterbore1246.

FIG.34is another oblique view of the solid body1200ofFIG.33showing the leading side1202, the second side1208, and the right side1210. The first side1206of the solid body1200(FIG.33) and the second side1208of the solid body1200(FIG.34) may be identical, interchangeable, or mirror images of each other. An inferior lobe1242is shown on the second side1208extending from the left trailing portion of the second side toward a central region of the second side1208. The inferior lobe1242may be identical to the superior lobe1224, interchangeable, or mirror images. This view shows a supporting structure1250around the centralized bore1244. The supporting structure1250projects from the trailing side1204into the central cavity1226along the trailing-leading direction, and may taper down in height along the trailing-leading direction.

FIGS.35-40show the placement of the features of the solid body1200in relation to the leading side1202and the trailing side1204; the location of the projections1220,1222on the perimeters of the first and second sides1206,1208, the superior lobe1224, the inferior lobe1242, the lobal aperture1230, the right bore1228, the left bore1240, and the centralized bore1244.FIG.40is a cross-sectional view along section line40-40ofFIG.37, showing the depth of the centralized bore1244and the surrounding supporting structure1250.

Referring toFIGS.41-48, the porous body1300has a leading side1302and a trailing side1304. In this embodiment, the leading side1302may be a posterior side and the trailing side1304may be an anterior side. The porous body1300has a first side1306that may be considered the top or superior aspect of the porous body1300and a second side1308that may be considered the bottom or inferior aspect of the porous body1300; however, the top and bottom may also be interchangeable. The second side1308may be identical to the first side1306, or a mirror image. The porous body1300has a right side1310and a left side1312; however, the left and right sides may also be interchangeable. The left side1312may be a mirror image of the right side1310as shown.

FIG.41is an oblique view of the porous body1300showing the trailing side1304, the first side1306, and the left side1312. The trailing side1304includes a right bore1314that surrounds the right bore1228of the solid body1200, and a left bore1316that surrounds the left bore1240of the solid body1200. The trailing side1304also includes a centralized bore1318that surrounds the centralized bore1244of the solid body1200. The centralized bore1318may be sized and shaped to receive the supporting structure1250of the solid body. Alternatively, at least for embodiments that are fabricated by additive manufacturing operations, the bore1318may have an inside diameter that is larger than the major diameter of the internal threads of the bore1244and/or the counterbore1246. The first side1306of the porous body1300features a superior porous structure1320with one or more raised prominences of porous material: a leading prominence1322and a trailing prominence1324are shown, both having a round shape and both fitting within the lobal aperture1230(seeFIG.26). Any number of prominences may be included, and the prominences may have any shape. Preferably, the number and shape of the prominences may correspond to the number and shape of the lobal aperture(s) of the solid body1200. Referring toFIGS.45-48, each prominence may include a domed or bulging superior surface to enhance contact with the adjacent vertebral endplate. The superior porous structure1320may include a pedestal1326that extends internally from the first side1306. The pedestal may taper toward the trailing side1304as it extends. The pedestal1326may form a wall around the right bore1314. The first side1306of the porous body1300and the second side1308of the porous body1300are interchangeable, identical, or mirror images.

FIG.42is another oblique view of the porous body1300ofFIG.41showing the leading side1302, the second side1308, and the right side1310. The porous body1300includes an inferior porous structure1328which may be identical to the superior porous structure1320as shown, interchangeable, or mirror images. The first side1306of the porous body1300is a mirror image of the second side1308of the porous body1308and may be interchangeable.

FIGS.43-48show the structure of the porous body1300indicating the placement of the superior porous structure1320and the inferior porous structure1328. The second side1308is the mirror image of the first side1306.FIG.48depicts the mounding on top of the superior and inferior prominences1322,1324. When the solid body1200and the porous body1300are coupled together or superimposed, the porous prominences on both the first side1306and the second side1308are seated within the lobal apertures of the solid body1200in such a way that the mounds on top of the prominences may extend above, or outward from, the surfaces of the lobes of the solid body1200. This extension allows the vertebral bone to contact the porous body1300first under compression to promote bone growth into the porous material.FIG.48is a cross-sectional view ofFIG.45along section line48-48that shows the centralized bore1318.

Referring toFIGS.49-51, a helical blade1450has a head1452that includes a drive and/or insertion feature1454to receive torque from a screw driver or inserter tool (not shown). The drive and/or insertion feature1454is illustrated as an internally threaded socket for one-way torque transmission or for connection to an inserter tool. The head1452may also include one or more notches1456; four notches are shown, evenly arranged around an exterior top edge of the head. Below the head1452is a tapered portion1458. Below the tapered portion is a helically fluted shank1460or shaft that may have a tapered end1462. Referring toFIG.50, three helical flutes are shown, each with an associated land1464extending along an outer diameter of the shank1460. The helical flute profile may form an undercut so that each flute includes a neck1466that is narrower than the land1464to enhance fixation within bone. The neck1466is located interior to the land1464. The pitch of the helical flutes may be substantially equal to the length of the helically fluted shank1460. The helical blade1450may be impacted into bone with a mallet or other tool, or it may be inserted by rotating it like a screw.

Referring toFIGS.29,32,52, and53, the collar1550may be referred to as a washer or a cam. The collar1550may have a non-circular outer profile, which may include a pair of tabs1552extending from opposite sides of the collar and/or a pair of indentations1554extending into opposite sides of the collar. The top surface of each tab1552may include a recess1556, which may be semicircular as shown. A central through hole1558may extend through the collar1550. A counterbore1560may be associated with the hole1558on the top side of the collar1550.

Referring toFIGS.32and54, the bushing1500may be referred to as a screw. The bushing1500has a head1502that may include a drive feature1504to receive torque from a screw driver (not shown). The drive feature1504may include one or more indentations1506in an exterior top edge of the head1502; four semicircular indentations are shown, evenly arranged around the head. Below the head1502is a threaded shank1508or shaft which may be complementary to the internal threads of the counterbore1246. A central longitudinal hole1510may extend through the bushing1500.

The solid body1200and the porous body1300may be fabricated together at the same time via additive manufacturing technology. Thus, the disclosed solid body1200and porous body1300may be superimposed or “occupy the same space.” The material of the solid body1200may be fully dense or non-porous, or the material may be distinctly more dense or less porous than the porous body1300. The solid body200may be 80% to 100% dense. The porous body1300may be 80%±10% dense or 80%±5% dense. The material of the porous body1300may have one or more pore sizes and/or shapes which are favorable for bone ongrowth/ingrowth. The material of the porous body1300may have a consistent porous structure throughout, or there may be one or more gradients or abrupt changes in porous structure. The porous body1300may provide sufficient internal support structure to the solid body lobes so that no additional temporary support structure is required to ensure that the solid body builds according to specifications via additive manufacturing process. Preferably, the taper angles of the pedestals1326of the porous body1300may be selected to be compatible with the taper angles that a given additive manufacturing system will build without additional temporary support structure and with satisfactory finished product. Preferably, the taper angles of the pedestals1326of the porous body1300may be 45° or less. In one example, the solid body1200and the porous body1300may be fabricated together by additive manufacturing with the solid and porous bodies1200,1300superimposed and oriented so that the leading side1202is the base on which the bodies are built or printed, in other words, the first layer of the build, and the trailing side1204includes the last layer of the build. In another example, the build orientation may be reversed so that the build starts with the trailing side1204and ends with the leading side1202.

The centralized bore1318of the porous body surrounds the centralized bore1244of the solid body, and may optionally receive the supporting structure1250. The right bore1314surrounds the right bore1228. The left bore1316surrounds the left bore1240. The superior porous structure1320supports the superior lobe1224. The inferior porous structure1328supports the inferior lobe1242. The porous prominences1322,1324may extend outwardly through the aperture1230as shown. Alternatively, the solid structure of the lobes1224,1242may extend outwardly past the porous structures1320,1328and corresponding prominences1322,1324. The porous body1300may fill only a portion of the central cavity1226of the solid body, so that a portion of the cavity1226remains empty to receive bone graft or other therapeutic agents. Preferably, the empty portion of the cavity1226extends through the interconnected solid and porous bodies1200,1300along a superior-inferior direction. The porous body1300, or at least the superior and inferior porous structures1320,1328, may be flexible enough to permit the lobes1224,1242to flex inwardly toward a central transverse plane of the implant under compressive loads applied by adjacent superior and inferior vertebrae. The central transverse plane of the implant is represented by section line36-36ofFIG.37and section line44-44ofFIG.45. The central sagittal plane of the implant is represented by section lines32-32ofFIG.29,40-40ofFIG.37, and48-48ofFIG.45.

The intervertebral spacer implant system1100may be assembled by providing the solid body1200and the porous body1300fabricated together as a single integral part; placing the bottom side of the collar1550against the sunken region1248of the solid body1200, optionally with the tabs1552extending toward the first and second sides1206,1208; inserting the threaded shank1508of the bushing1500through the hole1558and threading it into the internal threads of the counterbore1246, optionally leaving the threaded interconnection loose or less than fully tight; inserting the helically fluted shank1460of the helical blade1450into the right bore1228so that the head1452is at or near the trailing side1204and the helically fluted shank1460protrudes from the first side1206; inserting the threaded shank410of the bone screw404into the left bore1240so that the head406is at or near the trailing side1204and the threaded shank410protrudes from the second side1208; rotating the collar1550so that the tabs1552extend toward the right and left sides1210,1212, optionally with a portion of one tab1552received in a notch1456; and fully tightening the bushing1500to lock the collar1550in position to prevent the helical blade1450and/or the bone screw404from backing out of the right and left bores1228,1240, respectively. Optionally, the bone screw404may be inserted into the right bore1228and the helical blade1450may be inserted into the left bore1240. Optionally, bone screws402,404or two helical blades1450may be inserted into the right and left bores1228,1240.

A method of implanting the intervertebral spacer implant system1100may include some or all of the following steps in any order: creating a surgical access to an operative site, removing a disc from between adjacent superior and inferior vertebrae, inserting the leading side of the solid/porous spacer1200,1300along a trailing-leading direction into the prepared disc space, optionally drilling for the bone screw(s)404and/or helical blade(s)1450, inserting the bone anchors through the bores1228,1240and into the vertebral bodies, and after the bone anchors are fully inserted, rotating the collar1550so that the tabs1552cover at least a portion of each bone anchor head, including optionally engaging a notch1456, tightening the bushing1500in the counterbore1246, and closing the surgical access.

Referring toFIGS.55A-57B, a porous body1600is shown to illustrate an example porous structure. The porous structure illustrated by porous body1600may be included in porous bodies300,1300.FIG.55Ais a top view of the porous body1600andFIG.55Bis an enlarged detail view of a portion of the porous body1600ofFIG.55A, showing that in the top view, the porous structure is formed by interconnecting struts1614which define hexagonal pores1616that extend straight through the porous body1600. Similarly,FIG.57Ais a side view of the porous body1600andFIG.57Bis an enlarged detail view of a portion of the porous body1600ofFIG.57A, showing that in the side view, the porous structure is formed by interconnecting struts1618which define hexagonal pores1620that extend straight through the porous body1600. The size, shape, and orientation of the struts1614and pores1616shown inFIGS.55A-Bmay be the same as inFIGS.57A-B, or different as shown.FIG.56Ais a front view of the porous body1600andFIG.56Bis an enlarged detail view of a portion of the porous body1600ofFIG.56A, showing that in the front view, the porous structure is formed by interconnecting struts1622which define rectangular (or square) pores1624that extend straight through the porous body1600. The rectangular pores1624may have the same cross-sectional area as the hexagonal pores1616,1620, or different as shown.FIGS.56A-Balso show that the porous structure may be formed by interconnecting perpendicular layers corresponding toFIGS.55A-Band57A-B. It will be appreciated that the porous structure may include additional void space besides the hexagonal and rectangular pores1616,1620,1624.

Any methods disclosed herein includes one or more steps or actions for performing the described method. The method steps and/or actions may be interchanged with one another. In other words, unless a specific order of steps or actions is required for proper operation of the embodiment, the order and/or use of specific steps and/or actions may be modified.

Reference throughout this specification to “an embodiment” or “the embodiment” means that a particular feature, structure or characteristic described in connection with that embodiment is included in at least one embodiment. Thus, the quoted phrases, or variations thereof, as recited throughout this specification are not necessarily all referring to the same embodiment.

Similarly, it should be appreciated that in the above description of embodiments, various features are sometimes grouped together in a single embodiment, Figure, or description thereof for the purpose of streamlining the disclosure. This method of disclosure, however, is not to be interpreted as reflecting an intention that any claim require more features than those expressly recited in that claim. Rather, as the following claims reflect, inventive aspects lie in a combination of fewer than all features of any single foregoing disclosed embodiment. Thus, the claims following this Detailed Description are hereby expressly incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment. This disclosure includes all permutations of the independent claims with their dependent claims.

Recitation in the claims of the term “first” with respect to a feature or element does not necessarily imply the existence of a second or additional such feature or element. Elements recited in means-plus-function format are intended to be construed in accordance with 35 U.S.C. § 112 Para. 6. It will be apparent to those having skill in the art that changes may be made to the details of the above-described embodiments without departing from the underlying principles of the technology.

While specific embodiments and applications of the present technology have been illustrated and described, it is to be understood that the technology is not limited to the precise configuration and components disclosed herein. Various modifications, changes, and variations which will be apparent to those skilled in the art may be made in the arrangement, operation, and details of the methods and systems of the present technology disclosed herein without departing from the spirit and scope of the technology.