Extendable spinal implant

Abstract

An extendable spinal implant includes a stationary plate having a housing and a first plate body defining a tissue-engaging surface, a bearing nut having internal threading and including a collar and a tube body, and an extendable plate including a threaded shaft and a second plate body defining a second tissue-engaging surface. First and second one-way ratchet interfaces of the housing and the collar, respectively, are configured to engage one another permitting rotation of the bearing nut in a first rotational direction and inhibiting rotation thereof in a second, opposite rotational direction. Thus, axial extension of the extendable plate from the housing which rotates the bearing nut in the first rotational direction is permitted while axial retraction of the extendable plate into the housing is inhibited by the engagement of the first and second one-way ratchet interfaces inhibiting rotation of the bearing nut in the second, opposite rotational direction.

Description

A0012381US01 (10259BS-503-PCT)EXTENDABLE SPINAL IMPLANT FIELD

[0001] The present disclosure relates to spinal surgery and, more particularly, to an extendable spinal implant for treating disorders of the spine.BACKGROUND

[0002] Spinal disorders such as scoliosis and other curvature abnormalities, kyphosis, degenerative disc disease, disc herniation, osteoporosis, spondylolisthesis, stenosis, tumors, and fracture may result from trauma, disease, and / or degenerative conditions and may cause patient pain, deformity, nerve damage, and / or loss of mobility.

[0003] Surgical treatment of spinal disorders may include the removal of tissue from a patient’s spine. The excision of at least a portion of a vertebrae, for example, is referred to as a corpectomy, whereas the excision of at least a portion of a disc, as another example, is referred to as discectomy. Corpectomy and discectomy spinal surgical procedures, which may be performed in conjunction with one another, typically involve the installation of a spinal implant between the remaining tissue structures of the patient’s spine to structurally support the spine in the absence of the excised tissue.SUMMARY

[0004] Any or all of the aspects described herein, to the extent consistent, may be used in conjunction with any or all of the other aspects described herein.

[0005] Provided in accordance with aspects of the present disclosure is an extendable spinal implant including a stationary plate, a bearing nut, and an extendable plate. The stationary plate includes a first plate body defining a first tissue-engaging surface and a housing extending from the first plate body opposite the first tissue-engaging surface to a free end of the housing. The housing includes a first one-way ratchet interface disposed at the free end thereof. The bearing nut has internal threading and includes a collar and a tube body extending from the collar. The collar includes a second one-way ratchet interface disposed about the tube body. The bearing nut is configured for positioning with the tube body extending into the housing and the collar disposed on the free end of the housing such that the first and second one-way ratchet interfaces engage one another to permit rotation of the bearing nut in a first rotational direction while inhibiting rotation of the bearing nut in a second, opposite rotational direction. The extendable plate includes a second plate body defining a second tissue-engaging surface and a threaded shaft extending from the secondA0012381US01 (10259BS-503-PCT)plate body opposite the second tissue-engaging surface. The threaded shaft is configured to threadingly engage the internal threading of the bearing nut and to extend at least partially into the housing. Axial extension of the extendable plate from the housing rotates the bearing nut in the first rotational direction. The extendable plate is inhibited from axial retraction into the housing by the engagement of the first and second one-way ratchet interfaces inhibiting rotation of the bearing nut in the second, opposite rotational direction.

[0006] In an aspect of the present disclosure, external threading of the threaded shaft and the internal threading of the bearing nut are configured as self-locking threadforms to inhibit axial movement of the extendable plate from the housing in the absence of sufficient force urging the extendable plate from the housing. The self-locking threadforms may be trapezoidal threadforms.

[0007] In another aspect of the present disclosure, at least one bearing is disposed between the housing and the bearing nut to facilitate rotation of the bearing nut relative to the housing. The at least one bearing may be partially received within an annular channel defined within the tube body of the bearing nut and / or may extend through an aperture defined within the housing.

[0008] In still another aspect of the present disclosure, an access opening is defined through a side wall of the housing to expose a portion of the threaded shaft, wherein a tool is configured for insertion through the access opening and into engagement with the portion of the threaded shaft to drive axial extension of the extendable plate.

[0009] In yet another aspect of the present disclosure, the portion of the threaded shaft includes a gear rack and the tool includes a gear driver configured to engage the gear rack and drive axial extension of the extendable plate in response to rotation of the gear driver.

[0010] In still yet another aspect of the present disclosure, at least one of the first or second one-way ratchet interfaces is axially movable relative to the other from an engaged position, permitting axial extension of the extendable plate while inhibiting axial retraction of the extendable plate, to a disengaged position, permitting both axial extension and axial retraction of the extendable plate.

[0011] In another aspect of the present disclosure, the collar of the bearing nut further includes a first bevel gear, and a tool having a second bevel gear is configured to engage the first and second bevel gears with one another in substantially perpendicular orientation relative to one another such that rotational driving of the second bevel gear drives rotation of the first bevel gear and, thus, the bearing nut in the first rotational direction to drive axial extension of the extendable plate from the housing.A0012381US01 (10259BS-503-PCT)

[0012] Another extendable spinal implant provided in accordance with the present disclosure is configured for positioning within a free space defined between first and second vertebrae portions (e.g., first and second vertebrate or first and second portions of the same vertebrae). The extendable spinal implant includes a stationary plate, a bearing nut, and an extendable plate. The stationary plate includes a first plate body defining a first tissueengaging surface configured to engage the first vertebrae portion and a housing extending from the first plate body opposite the first tissue-engaging surface to a free end of the housing. The bearing nut has internal threading and includes a collar and a tube body extending from the collar. The bearing nut is configured for positioning with the tube body extending into the housing and the collar disposed on the free end of the housing. The extendable plate includes a second plate body defining a second tissue-engaging surface configured to engage the first vertebrae portion and a threaded shaft extending from the second plate body opposite the second tissue-engaging surface. The threaded shaft is configured to threadingly engage the internal threading of the bearing nut and to extend at least partially into the housing. A first one-way ratchet interface is associated with the free end of the housing and a second one-way ratchet interface is associated with the collar of the bearing nut. The first and second one-way ratchet interfaces are configured to engage one another to permit rotation of the bearing nut in a first rotational direction relative to the housing corresponding to axial extension of the extendable plate from the housing and to inhibit rotation of the bearing nut in a second rotational direction relative to the housing corresponding to axial retraction of the extendable plate into the housing such that axial extension of the extendable plate from the housing is permitted while axial retraction of the extendable plate into the housing is inhibited.

[0013] In an aspect of the present disclosure, the first one-way ratchet interface is annularly disposed about the free end of the housing and / or the second one-way ratchet interface is disposed on an annular surface of the collar that surrounds the threaded shaft.

[0014] In another aspect of the present disclosure, external threading of the threaded shaft and the internal threading of the bearing nut are configured as self-locking threadforms to inhibit axial movement of the extendable plate from the housing in the absence of sufficient force urging the extendable plate from the housing.

[0015] In still another aspect of the present disclosure, at least one bearing is disposed between the housing and the bearing nut to facilitate rotation of the bearing nut relative to the housing.A0012381US01 (10259BS-503-PCT)

[0016] In yet another aspect of the present disclosure, an access opening is defined through a side wall of the housing to expose a portion of the threaded shaft. In such aspects, a tool is configured for insertion through the access opening and into engagement with the portion of the threaded shaft to drive axial extension of the extendable plate. More specifically, in aspects, the portion of the threaded shaft includes a gear rack and the tool includes a gear driver configured to engage the gear rack and drive axial extension of the extendable plate in response to rotation of the gear driver.

[0017] In still yet another aspect of the present disclosure, at least one of the first or second one-way ratchet interfaces is axially movable relative to the other from an engaged position, permitting axial extension of the extendable plate while inhibiting axial retraction of the extendable plate, to a disengaged position, permitting both axial extension and axial retraction of the extendable plate.

[0018] In another aspect of the present disclosure, the collar of the bearing nut further includes a first bevel gear, and a tool having a second bevel gear is configured to engage the first and second bevel gears with one another such that rotational driving of the second bevel gear drives rotation of the first bevel gear and, thus, the bearing nut in the first rotational direction to drive axial extension of the extendable plate from the housing. In such aspects, the first and second bevel gears may be configured to engage one another in substantially perpendicular orientation relative to one another.BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other aspects and features of the present disclosure will become more apparent in light of the following detailed description when taken in conjunction with the accompanying drawings wherein like reference numerals identify similar or identical elements.

[0020] FIGS. 1A and IB are side views of a patient’s spine prior to and after a corpectomy and / or discectomy spinal surgical procedure including implantation of an extendable spinal implant in accordance with the present disclosure;

[0021] FIGS. 2A and 2B are side views of the extendable spinal implant of FIG. IB, shown defining first and second heights, respectively;

[0022] FIG. 3 is an exploded, perspective view of the extendable spinal implant of FIG. IB;

[0023] FIGS. 4 and 5 are side views of the stationary plate and extendable plate, respectively, of the extendable spinal implant of FIG. IB;A0012381US01 (10259BS-503-PCT)

[0024] FIG. 6 is a perspective view of the bearing nut and one of the bearing pins of the extendable spinal implant of FIG. IB;

[0025] FIGS. 7-9 are side views illustrating incremental extension of the extendable plate of the extendable spinal implant of FIG. IB relative to the bearing nut and stationary plate of the extendable spinal implant of FIG. IB;

[0026] FIG. 10A is a perspective view of the extendable spinal implant of FIG. IB with an adjustment tool engaged with the extendable spinal implant to facilitate height extension thereof;

[0027] FIG. 10B is a perspective view illustrating engagement of the adjustment tool of FIG. 10A with the extendable plate of the extendable spinal implant of FIG. IB;

[0028] FIG. 11A is a side view of another extendable spinal implant provided in accordance with the present disclosure;

[0029] FIG. 1 IB is a side view of the extendable spinal implant of FIG. 11A with an adjustment tool engaged with the extendable spinal implant to facilitate height extension thereof; and

[0030] FIGS. 12-15 illustrate various different bearing configurations for use with the extendable spinal implants of FIGS. IB and 11 A.DETAILED DESCRIPTION

[0031] Referring to FIGS. 1A and IB, a corpectomy and / or discectomy spinal surgical procedure may be performed to remove tissue from a patient’s spine “S” such as, for example, at least a portion of one or more damaged or diseased vertebrae “DV” and one or more discs “DI”, “D2” on either side of the vertebrae “DV” to be at least partially removed. Once the tissue is removed, an implant such as, for example, and extendable spinal implant 100 provided in accordance with the present disclosure is installed in the free space “F” created by the removed tissue to provide structural support to the remaining vertebrae “V” and / or discs “D” of the patient’s spine “S”. Although extendable spinal implant 100 is shown in FIG. IB as a corpectomy and / or discectomy implant, use of extendable spinal implant 100 is not limited thereto as extendable spinal implant 100 may be utilized in conjunction with any suitable spinal surgical procedure and / or at any suitable spinal location, position, and / or orientation.

[0032] Turning to FIGS. 2A-6, extendable spinal implant 100 provided in accordance with the present disclosure includes a stationary plate 110, an extendable plate 130, a bearing nut 150, and one or more bearings 170. Referring in particular to FIGS. 2A-4, stationaryA0012381US01 (10259BS-503-PCT)plate 110 includes a plate body 112 and a housing 114 extending from plate body 112 in generally perpendicular orientation relative to a plane defined by a surface tissue-engaging surface 113 of plate body 112. Plate body 112 and housing 114 are fixed relative to one another, e.g., monolithically formed, welded, or otherwise fixed relative to one another. Housing 114 defines a substantially hollow interior configured to receive, as detailed below, threaded shaft 134 of extendable plate 130, bearing nut 150, and the one or more bearings 170. Housing 114 defines a first end 116 that is closed via plate body 112 and a second, open end 118. Housing 114 further includes an access opening 120 defined through a side wall thereof to enable access to components within the interior of housing 114 from the exterior of stationary plate 110, as detailed below. One or more transverse apertures 122 are also defined through a side wall of housing 114 substantially perpendicular and offset relative to a longitudinal axis of housing 114. For example, as shown in FIGS. 2A-4, a pair of apertures 122 on opposing sides of the longitudinal axis of housing 114 may be provided. Each aperture 122 is configured to receive a bearing 170 such as, for example, a bearing pin 172, as detailed below.

[0033] Second, open end 118 of housing 114 includes an annular ratchet interface 124 disposed thereon and surrounding the hollow interior of housing 114. Annular ratchet interface 124 includes a plurality of one-way ratchet teeth 126, e.g., each having an angled cam surface oriented in a first circumferential direction and a perpendicular stop surface oriented in a second, opposite circumferential direction, to enable rotation of a corresponding ratchet interface engaged with annular ratchet interface 124 in a first rotational direction and inhibit rotation of the corresponding ratchet interface in a second, opposite rotational direction while the corresponding ratchet interface is engaged with annular ratchet interface 124.

[0034] With reference to FIGS. 2A-3, and 5, extendable plate 130 includes a plate body 132 and a threaded shaft 134 extending from plate body 132 in generally perpendicular orientation relative to a plane defined by a surface tissue-engaging surface 133 of plate body 132. Plate body 132 and threaded shaft 134 are fixed relative to one another, e.g., monolithically formed, welded, or otherwise fixed relative to one another. Threaded shaft 134 is configured to extend through, in threaded engagement with, bearing nut 150 and to extend from bearing nut 150 at least partially into the hollow interior of housing 114. Threaded shaft 134 includes helical threading 136 disposed about the outer periphery thereof that is configured to threadingly engage bearing nut 150. Helical threading 136 defines a self-locking threadform, e.g., defining single start trapezoidal threading, to inhibitA0012381US01 (10259BS-503-PCT)translation of extendable plate 130 through and relative to bearing nut 150 in the absence of sufficient force applied to extendable plate 130, thereby retaining extendable plate 130 in a fixed, e.g., locked, position relative to bearing nut 150 and housing 114 unless sufficient force is applied to extendable plate 130.

[0035] Threaded shaft 134 of extendable plate 130 includes a longitudinal channel 138 recessed into a side wall of threaded shaft 134. Longitudinal channel 138 includes a gear rack 139 extending longitudinally along an inner wall defining longitudinal channel 138. With extendable plate 130 disposed within bearing nut 150 and housing 114 of stationary plate 110, longitudinal channel 138 is oriented to at least partially overlap access opening 120 of housing 114 below bearing nut 150, thus enabling access to longitudinal channel 138 from the exterior of extendable spinal implant 100.

[0036] Referring to FIGS. 2A-3 and 6, bearing nut 150 includes a collar 152 and a tube body 154 extending from collar 152. Bearing nut 150 is configured for positioning radially between threaded shaft 134 of extendable plate 130 and housing 114 of stationary plate 110 and longitudinally such that tube body 154 extends into housing 114 while collar 152 opposes open end 118 of housing 114. More specifically, collar 152 of bearing nut 150 defines an annular ratchet interface 156 on a surface 155 thereof that surrounds tube body 154 such that, with tube body 154 of bearing nut 150 extending into housing 114 and surface 155 of collar 152 opposing open end 118 of housing 114, annular ratchet interface 156 of collar 152 engages annular ratchet interface 124 of housing 114. Annular ratchet interface 156 includes a plurality of one-way ratchet teeth 158 that are complementary to one-way ratchet teeth 126 of annular ratchet interface 124 of housing 114, e.g., each having an angled cam surface oriented in a first circumferential direction and a perpendicular stop surface oriented in a second, opposite circumferential direction, to enable rotation of annular ratchet interface 156, when engaged with annular ratchet interface 124, in a first rotational direction and inhibit rotation of the annular ratchet interface 156 in a second, opposite rotational direction while engaged with annular ratchet interface 124.

[0037] Bearing nut 150 defines a threaded interior extending through tube body 154 and collar 152 and has helical threading 160 disposed about the inner periphery thereof. Helical threading 160 is complementary to helical threading 136 of extendable plate 130 and likewise defines a self-locking threadform, e.g., defining single start trapezoidal threading, to inhibit axial translation of extendable plate 130 through and relative to bearing nut 150 in the absence of sufficient force applied to extendable plate 130, thereby retaining extendable plate 130 in a fixed, e.g., locked, position relative to bearing nut 150 and housingA0012381US01 (10259BS-503-PCT)114 until sufficient force is applied to extendable plate 130. Thus, unintended collapse (or extension) of extendable spinal implant 100 is inhibited.

[0038] When sufficient force is applied to extendable plate 130 in a first direction such as, for example, force in an axial direction urging extendable plate 130 away from stationary plate 110, the engagement between annular ratchet interfaces 124, 156 of housing 114 and bearing nut 150, respectively, enables rotation of bearing nut 150 relative to housing 114 in the first rotational direction, thus enabling incremental axial extension of extendable plate 130 from stationary plate 110 as bearing nut 150 is rotated in the first rotational direction. However, due to the engagement between annular ratchet interfaces 124, 156 of housing 114 and bearing nut 150, respectively, application of an otherwise sufficient force to extendable plate 130 in a second direction such as, for example, force in an axial direction urging extendable plate 130 towards stationary plate 110, does not result in axial translation of extendable plate 130 because rotation of bearing nut 150 is inhibited by the interaction between one-way ratchet teeth 126, 158 of annular ratchet interfaces 124, 156, respectively. Accordingly, retraction of extendable plate 130 into housing 114 of stationary plate 110 is inhibited while annular ratchet interfaces 124, 156 are engaged with one another.

[0039] Continuing with reference to FIGS. 2A-3 and 6, bearing nut 150 further includes an annular channel 162 defined about the outer periphery of tube body 154. Annular channel 162 is configured to align with apertures 122 defined through housing 114 to couple the one or more bearings 170 between bearing nut 150 and housing 114 to facilitate smooth and reduced friction rotation of bearing nut 150 within housing 114. More specifically, the one or more bearings 170 may include first and second bearing pins 172 disposed within apertures 122 and extending through the hollow interior of housing 114 on either side of bearing nut 150 such that a portion of each bearing pin 172 is received within annular channel 162 of tube body 154 of bearing nut 150 on opposing sides of bearing nut 150. Bearing pins 172 may be welded within apertures 122 or otherwise secured therein. In aspects, an opposing aperture defined through housing 114 aligns with each aperture 122 to enable receipt of the corresponding bearing pin 172 to secure each bearing pin 172 relative to housing 114 at each end thereof. The relative diameters of bearing pins 172 and annular channel 162 may be selected such that receipt of bearing pins 172 within annular channel 162 of tube body 154 of bearing nut 150 maintains annular ratchet interfaces 124, 156 of housing 114 and bearing nut 150, respectively, in engagement with one another, while enabling sufficient axial play therebetween to enable camming of one-way ratchet teeth 126,A0012381US01 (10259BS-503-PCT)158 relative to one another as well as disengagement of ratchet interfaces 124, 156 from one another. Alternative or additional bearing configurations are detailed below.

[0040] Referring to FIGS. 7-9, in conjunction with FIGS. 2A-6, as detailed above, annular ratchet interfaces 124, 156 of housing 114 and bearing nut 150, respectively, enable one-way ratcheted extension of extendable plate 130 from stationary rod 110. That is, from the initial position shown in FIG. 7, and in response to an axial force urging extendable plate 130 away from stationary plate 110, e.g., in the axial direction “A,” bearing nut 150 is rotated in the rotational direction “R” such that the angled cam surfaces of one-way ratchet teeth 126, 158 of annular ratchet interfaces 124, 156, respectively, enable one-way ratchet teeth 126, 158 to incrementally cam over one another, as shown in FIG. 8, before dropping into engagement with the adjacent one-way ratchet teeth 126, 158, as shown in FIG. 9, thereby incrementally advancing extendable plate 130 in the axial direction “A” progressively from FIGS. 7-9.

[0041] However, and as also detailed above, the abutment of the perpendicular stop surfaces of one-way ratchet teeth 126, 158 of ratchet interfaces 124, 156, respectively, inhibit rotation of bearing nut 150 in a rotational direction opposite the rotational direction “R” such that extendable plate 130 is locked out from retracting back into stationary plate 110 after each incremental extension of extendable plate 130 from stationary plate 110. Thus, extension in height of extendable spinal implant 100 is readily enabled while retraction is inhibited. More specifically, with momentary reference back to FIG. IB, with extendable spinal implant 100 installed within the free space “F”, extendable spinal implant 100 can be increased in height to sufficiently engage tissue-engaging surfaces 113, 133 of plate bodies 112, 132 of stationary and extendable plates 110, 130, respectively, with the vertebrae “V” on either end of free space “F”. Collapse is inhibited after each incremental increase in height by both the engagement of one-way ratchet teeth 126, 158 of annular ratchet interfaces 124, 156 as well as by the self-locking configurations of helical threadings 136, 160 of extendable plate 130 and bearing nut 150, respectively.

[0042] With reference to FIGS. 10A and 10B, in order to enable the above-detailed height adjustment of extendable spinal implant 100, an adjustment tool 1000 having a shaft 1010 and a gear driver 1020 at the distal end of shaft 1010 may be inserted through access opening 120 of housing 114 of stationary plate 110 and into longitudinal channel 138 of threaded shaft 134 of extendable plate 130, whereby gear driver 1020 engages gear rack 139 of longitudinal channel 138 of threaded shaft 134 of extendable plate 130. With adjustment tool 1000 engaged in this manner, adjustment tool 1000 may be rotated (or otherwiseA0012381US01 (10259BS-503-PCT)actuated) to rotate gear driver 1020 such that, by the engagement of gear driver 1020 with gear rack 139, an axial pushing force is applied to extendable plate 130 to urge extendable plate 130 to extend farther from stationary plate 110, thereby increasing the height of extendable spinal implant 100. Bearing nut 150 is rotated in response to the translation of extendable plate 130 in the extending or height-increasing direction and, due to the one-way engagement of bearing nut 150 with housing 114, rotation of bearing nut 150 in the opposite direction is inhibited and, thus, translation of extendable plate 130 in a retracting or heightdecreasing direction is likewise inhibited while bearing nut 150 and housing 114 remain engaged.

[0043] Referring back to FIGS. 2A and 2B, as detailed above, extendable spinal implant 100 is configured to permit incremental height increase but is configured to one-way lock after each incremental height increase to inhibit retraction or height reduction of extendable spinal implant 100. However, there may be instances where height reduction of extendable spinal implant 100 is desired. In order to enable height reduction of extendable spinal implant 100, disengagement of annular ratchet interfaces 124, 156 (see FIGS. 7-9) of housing 114 and bearing nut 150, respectively, is required. More specifically, a disengagement tool (not shown) is engaged with housing 114 and / or collar 152 of bearing nut 150 and manipulated to axially separate housing 114 and collar 152 of bearing nut 150 from one another, thereby disengaging annular ratchet interfaces 124, 156 from one another. The disengagement tool may be, for example, a prying tool, a grasping tool, or any other suitable tool configured to enable axial separation of housing 114 and collar 152 of bearing nut 150 from one another. Further, in aspects, housing 114 and / or collar 152 of bearing nut 150 include holds, e.g., recesses, slots, and / or other features, to facilitate engagement of the disengagement tool therewith. With annular ratchet interfaces 124, 156 disengaged, anaxial force may be applied to urge extendable plate 130 towards stationary plate 110 and / or adjustment tool 1000 (FIGS. 10A and 10B) may be engaged as detailed above and driven in the second, opposite rotational direction to retract extendable plate 130 into housing 114 of stationary plate 110. Upon removal of the disengagement tool after the desired retraction is complete, bearing nut 150 is returned towards housing 114 to reengage ratchet interfaces 124, 156, thereby returning to the one-way ratcheting condition wherein extension of extendable plate 130 is permitted but retraction of extendable plate 130 is inhibited.

[0044] Turning to FIGS. 11 A and 1 IB, another extendable spinal implant 1100 provided in accordance with the present disclosure is shown. To the extent consistent, extendable spinal implant 1100 may include any of the features detailed above with respect toA0012381US01 (10259BS-503-PCT)extendable spinal implant 100 (FIGS. 2 A and 2B) and, thus, only differences therebetween are described in detail hereinbelow for purposes of brevity.

[0045] Bearing nut 1150 of extendable spinal implant 1100 includes a bevel gear 1182 defined on a surface 1180 of collar 1152 of bearing nut 1150 that opposes surface 1155 and surrounds the threaded interior of bearing nut 1150. Thus, rather than housing 1114 of stationary plate 1110 of extendable spinal implant 1100 defining an access opening providing access to a gear rack associated with extendable plate 1130 to enable height adjustment of extendable spinal implant 1100 as with extendable spinal implant 100 (FIGS.2A and 2B), extendable spinal implant 1100 is height adjustable via rotational driving of bevel gear 1182 to thereby drive rotation of bearing nut 1150 which, in turn, drives extension of extendable plate 1130 from stationary plate 1110 to increase the height of extendable spinal implant 1100. More specifically, an adjustment tool 1190 including a shaft 1192 having a bevel gear 1194 at the distal end thereof is manipulated into position such that bevel gear 1194 is disposed in meshed engagement with bevel gear 1182. With this engagement achieved, adjustment tool 1190 is rotated or otherwise actuated to drive rotation of bevel gear 1194, thereby driving rotation of bevel gear 1182 and increase the height of extendable spinal implant 1100. In aspects, bevel gears 1182, 1194, when engaged, are disposed in substantially perpendicular orientation relative to one another, thus facilitating insertion of adjustment tool 1190 and engagement of bevel gear 1194 of adjustment tool 1190 with bevel gear 1182 of collar 1152 of bearing nut 1150 of extendable spinal implant 1100 when extendable spinal implant 1100 is implanted at a surgical site.

[0046] With reference to FIGS. 12-15, in aspects, as an alternative or in addition to the one or more bearings 170 including bearing pins 172 (see FIG. 3), other suitable bearings may be provided. For example, as shown in FIG. 12, a plurality of ball bearings 1272 may be disposed within annular channel 162 of tube body 154 of bearing nut 150 (and, in aspects, within a corresponding annular channel defined within the interior surface of housing 114) to facilitate smooth and reduced friction rotation of bearing nut 150 within housing 114 of stationary plate 110.

[0047] FIG. 13 illustrates another bearing in the form of a self-lubricating material 1300 overmolded or otherwise disposed on bearing nut 150 and protruding therefrom (e.g., protruding from the outer surface thereof or protruding from an annular channel defined within the outer surface) to facilitate smooth and reduced friction rotation of bearing nut 150 within housing 114 of stationary plate 110.A0012381US01 (10259BS-503-PCT)

[0048] As another example, FIG. 14 illustrates a bearing 1400 including an outer ring 1410 formed by or configured to engage housing 114 of stationary plate 110, an inner ring 1420 formed by or engaged with bearing nut 150, and a plurality of ball bearings (not shown; see ball bearings 1172 (FIG. 12)) captured between inner and outer rings 1410, 1420. Bearing 1400 facilitates smooth and reduced friction rotation of bearing nut 150 within housing 114. As bearing 1400 retains the ball bearings between outer and inner rings 1410, 1420, respectively, the need for annular channels defined in bearing nut 150 and housing 114 is obviated and, thus, these annular channels can be omitted.

[0049] As shown in FIG. 15, an O-ring bearing 1500 may be provided for positioning within annular channel 162 of tube body 154 of bearing nut 150 to function as a bearing to facilitate smooth and reduced friction rotation of bearing nut 150 within housing 114 of stationary plate 110. O-ring bearing 1500 may be formed from a relatively hard material to inhibit compression or flexion of O-ring bearing 1500 in use.

[0050] Aspects of this disclosure may be further described by reference to the following numbered paragraphs:

[0051] 1. An extendable spinal implant, comprising: a stationary plate including a first plate body defining a first tissue-engaging surface and a housing extending from the first plate body opposite the first tissue-engaging surface to a free end of the housing, the housing including a first one-way ratchet interface disposed at the free end thereof; a bearing nut having internal threading and including a collar and a tube body extending from the collar, the collar including a second one-way ratchet interface disposed about the tube body, wherein the bearing nut is configured for positioning with the tube body extending into the housing and the collar disposed on the free end of the housing such that the first and second one-way ratchet interfaces engage one another to permit rotation of the bearing nut in a first rotational direction while inhibiting rotation of the bearing nut in a second, opposite rotational direction; and an extendable plate including a second plate body defining a second tissue-engaging surface and a threaded shaft extending from the second plate body opposite the second tissue-engaging surface, the threaded shaft configured to threadingly engage the internal threading of the bearing nut and to extend at least partially into the housing, wherein axial extension of the extendable plate from the housing rotates the bearing nut in the first rotational direction, and wherein the extendable plate is inhibited from axial retraction into the housing by the engagement of the first and second one-way ratchet interfaces inhibiting rotation of the bearing nut in the second, opposite rotational direction.A0012381US01 (10259BS-503-PCT)

[0052] 2. The extendable spinal implant according to paragraph 1, wherein external threading of the threaded shaft and the internal threading of the bearing nut are configured as self-locking threadforms to inhibit axial movement of the extendable plate from the housing in the absence of sufficient force urging the extendable plate from the housing.

[0053] 3. The extendable spinal implant according to paragraph 2, wherein the selflocking threadforms are trapezoidal threadforms.

[0054] 4. The extendable spinal implant according to any one of paragraphs 1-3, further comprising at least one bearing disposed between the housing and the bearing nut to facilitate rotation of the bearing nut relative to the housing.

[0055] 5. The extendable spinal implant according to paragraph 4, wherein the at least one bearing is partially received within an annular channel defined within the tube body of the bearing nut.

[0056] 6. The extendable spinal implant according to paragraph 4 or 5, wherein the at least one bearing extends through an aperture defined within the housing.

[0057] 7. The extendable spinal implant according to any one of paragraphs 1-6, further comprising an access opening defined through a side wall of the housing to expose a portion of the threaded shaft, wherein a tool is configured for insertion through the access opening and into engagement with the portion of the threaded shaft to drive axial extension of the extendable plate.

[0058] 8. The extendable spinal implant according to paragraph 7, wherein the portion of the threaded shaft includes a gear rack and wherein the tool includes a gear driver configured to engage the gear rack and drive axial extension of the extendable plate in response to rotation of the gear driver.

[0059] 9. The extendable spinal implant according to any one of paragraphs 1-8, wherein at least one of the first or second one-way ratchet interfaces is axially movable relative to the other from an engaged position, permitting axial extension of the extendable plate while inhibiting axial retraction of the extendable plate, to a disengaged position, permitting both axial extension and axial retraction of the extendable plate.

[0060] 10. The extendable spinal implant according to any one of paragraphs 1-9, wherein the collar of the bearing nut further includes a first bevel gear, and wherein a tool having a second bevel gear is configured to engage the first and second bevel gears with one another in substantially perpendicular orientation relative to one another such that rotational driving of the second bevel gear drives rotation of the first bevel gear and, thus, the bearingA0012381US01 (10259BS-503-PCT)nut in the first rotational direction to drive axial extension of the extendable plate from the housing.

[0061] 11. An extendable spinal implant configured for positioning within a free space defined between first and second vertebrae portions, the extendable spinal implant comprising: a stationary plate including a first plate body defining a first tissue-engaging surface configured to engage the first vertebrae portion and a housing extending from the first plate body opposite the first tissue-engaging surface to a free end of the housing; a bearing nut having internal threading and including a collar and a tube body extending from the collar, wherein the bearing nut is configured for positioning with the tube body extending into the housing and the collar disposed on the free end of the housing; an extendable plate including a second plate body defining a second tissue-engaging surface configured to engage the first vertebrae portion and a threaded shaft extending from the second plate body opposite the second tissue-engaging surface, the threaded shaft configured to threadingly engage the internal threading of the bearing nut and to extend at least partially into the housing; a first one-way ratchet interface associated with the free end of the housing; and a second one-way ratchet interface associated with the collar of the bearing nut, wherein the first and second one-way ratchet interfaces are configured to engage one another to permit rotation of the bearing nut in a first rotational direction relative to the housing corresponding to axial extension of the extendable plate from the housing and to inhibit rotation of the bearing nut in a second rotational direction relative to the housing corresponding to axial retraction of the extendable plate into the housing such that axial extension of the extendable plate from the housing is permitted while axial retraction of the extendable plate into the housing is inhibited.

[0062] 12. The extendable spinal implant according to paragraph 11, wherein the first one-way ratchet interface is annularly disposed about the free end of the housing.

[0063] 13. The extendable spinal implant according to paragraph 11 or 12, wherein the second one-way ratchet interface is disposed on an annular surface of the collar that surrounds the threaded shaft.

[0064] 14. The extendable spinal implant according to any one of paragraphs 11-13, wherein external threading of the threaded shaft and the internal threading of the bearing nut are configured as self-locking threadforms to inhibit axial movement of the extendable plate from the housing in the absence of sufficient force urging the extendable plate from the housing.A0012381US01 (10259BS-503-PCT)

[0065] 15. The extendable spinal implant according to any one of paragraphs 11-14, further comprising at least one bearing disposed between the housing and the bearing nut to facilitate rotation of the bearing nut relative to the housing.

[0066] 16. The extendable spinal implant according to any one of paragraphs 11-15, further comprising an access opening defined through a side wall of the housing to expose a portion of the threaded shaft, wherein a tool is configured for insertion through the access opening and into engagement with the portion of the threaded shaft to drive axial extension of the extendable plate.

[0067] 17. The extendable spinal implant according to paragraph 16, wherein the portion of the threaded shaft includes a gear rack and wherein the tool includes a gear driver configured to engage the gear rack and drive axial extension of the extendable plate in response to rotation of the gear driver.

[0068] 18. The extendable spinal implant according to any one of paragraphs 11-17, wherein at least one of the first or second one-way ratchet interfaces is axially movable relative to the other from an engaged position, permitting axial extension of the extendable plate while inhibiting axial retraction of the extendable plate, to a disengaged position, permitting both axial extension and axial retraction of the extendable plate.

[0069] 19. The extendable spinal implant according to any one of paragraphs 11-18, wherein the collar of the bearing nut further includes a first bevel gear, and wherein a tool having a second bevel gear is configured to engage the first and second bevel gears with one another such that rotational driving of the second bevel gear drives rotation of the first bevel gear and, thus, the bearing nut in the first rotational direction to drive axial extension of the extendable plate from the housing.

[0070] 20. The extendable spinal implant according to paragraph 19, wherein the first and second bevel gears are configured to engage one another in substantially perpendicular orientation relative to one another.

[0071] While several aspects of the disclosure have been detailed above and are shown in the drawings, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description and accompanying drawings should not be construed as limiting, but merely as exemplifications of particular aspects. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.

Claims

A0012381US01 (10259BS-503-PCT)WHAT IS CLAIMED IS:

1. An extendable spinal implant (100), comprising:a stationary plate (110) including a first plate body (112) defining a first tissueengaging surface (113) and a housing (114) extending from the first plate body (112) opposite the first tissue-engaging surface (113) to a free end of the housing (114), the housing (114) including a first one-way ratchet interface (124) disposed at the free end thereof;a bearing nut (150) having internal threading (160) and including a collar (152) and a tube body (154) extending from the collar (152), the collar (152) including a second oneway ratchet interface (156) disposed about the tube body (154), wherein the bearing nut (150) is configured for positioning with the tube body (154) extending into the housing (114) and the collar (152) disposed on the free end of the housing (114), such that the first and second one-way ratchet interface (124, 156) engage one another to permit rotation of the bearing nut (150) in a first rotational direction while inhibiting rotation of the bearing nut (150) in a second, opposite rotational direction; andan extendable plate (130) including a second plate body (132) defining a second tissue-engaging surface (133) and a threaded shaft (134) extending from the second plate body (132) opposite the second tissue-engaging surface (133), the threaded shaft (134) configured to threadingly engage the internal threading (160) of the bearing nut (150) and to extend at least partially into the housing (114), wherein axial extension of the extendable plate (130) from the housing (114) rotates the bearing nut (150) in the first rotational direction, and wherein the extendable plate (130) is inhibited from axial retraction into the housing (114) by the engagement of the first and second one-way ratchet interface (124, 156) inhibiting rotation of the bearing nut (150) in the second, opposite rotational direction.

2. The extendable spinal implant (100) according to claim 1, wherein external threading (136) of the threaded shaft (134) and the internal threading (160) of the bearing nut (150) are configured as self-locking threadforms to inhibit axial movement of the extendable plate (130) from the housing (114) in the absence of sufficient force urging the extendable plate (130) from the housing (114).

3. The extendable spinal implant (100) according to claims 1-2, further comprising at least one bearing (170) disposed between the housing (114) and the bearing nut (150) to facilitate rotation of the bearing nut (150) relative to the housing (114); wherein the at least one bearing (170) is partially received within an annular channel (162) defined within theA0012381US01 (10259BS-503-PCT)tube body (154) of the bearing nut (150); and wherein the at least one bearing extends through an aperture defined within the housing (11 ).

4. The extendable spinal implant (100) according to claims 1-3, further comprising an access opening (120) defined through a side wall of the housing (114) to expose a portion of the threaded shaft (134), wherein a tool is configured for insertion through the access opening (120) and into engagement with the portion of the threaded shaft (134) to drive axial extension of the extendable plate (130).

5. The extendable spinal implant (100) according to claim 4, wherein the portion of the threaded shaft (134) includes a gear rack (139) and wherein the tool includes a gear driver (1020) configured to engage the gear rack (139) and drive axial extension of the extendable plate (130) in response to rotation of the gear driver (1020).

6. The extendable spinal implant (100) according to claims 1-4, wherein at least one of the first or second one-way ratchet interface (124, 156) is axially movable relative to the other from an engaged position, permitting axial extension of the extendable plate (130) while inhibiting axial retraction of the extendable plate (130), to a disengaged position, permitting both axial extension and axial retraction of the extendable plate (130).

7. The extendable spinal implant (100) according to claims 1-6, wherein the collar (152) of the bearing nut (150) further includes a first bevel gear (1182), and wherein a tool (1190) having a second bevel gear (1194) is configured to engage the first and second bevel gears (1182, 1194) with one another in substantially perpendicular orientation relative to one another such that rotational driving of the second bevel gear (1194) drives rotation of the first bevel gear (1182) and, thus, the bearing nut (150) in the first rotational direction to drive axial extension of the extendable plate (130) from the housing (114).

8. The extendable spinal implant (100) according to claims 1-7, wherein the first oneway ratchet interface (124) is annularly disposed about the free end of the housing (114).

9. The extendable spinal implant (100) according to claim 1-8, wherein the second oneway ratchet interface (156) is disposed on an annular surface of the collar (152) that surrounds the threaded shaft (134).

10. The extendable spinal implant (100) according to any one of claims 1-9, wherein external threading (136) of the threaded shaft (134) and the internal threading (160) of the bearing nut (150) are configured as self-locking threadforms to inhibit axial movement of the extendable plate (130) from the housing (114) in the absence of sufficient force urging the extendable plate (130) from the housing (114).A0012381US01 (10259BS-503-PCT)11. The extendable spinal implant (100) according to any one of claims 1-10, further comprising at least one bearing disposed between the housing (114) and the bearing nut (150) to facilitate rotation of the bearing nut (150) relative to the housing (114).

12. The extendable spinal implant (100) according to any one of claims 1-11, further comprising an access opening (120) defined through a side wall of the housing (114) to expose a portion of the threaded shaft (134), wherein a first tool (1000) is configured for insertion through the access opening (120) and into engagement with the portion of the threaded shaft (134) to drive axial extension of the extendable plate (130).

13. The extendable spinal implant (100) according to claim 1-12, wherein the portion of the threaded shaft (134) includes a gear rack (139) and wherein the first tool (1000) a gear driver (1020) configured to engage the gear rack (139) and drive axial extension of the extendable plate (130) in response to rotation of the gear driver (1020).

14. The extendable spinal implant (100) according to any one of claims 1-13, wherein at least one of the first or second one-way ratchet interfaces (124, 156) is axially movable relative to the other from an engaged position, permitting axial extension of the extendable plate (130) while inhibiting axial retraction of the extendable plate (130), to a disengaged position, permitting both axial extension and axial retraction of the extendable plate (130).

15. The extendable spinal implant (100) according to any one of claims 1-14, wherein the collar (152) of the bearing nut (150) further includes a first bevel gear (1182), and wherein a second tool (1190) having a second bevel gear (1194) is configured to engage the first and second bevel gears (1182, 1194) to one another such that rotational driving of the second bevel gear (1194) drives rotation of the first bevel gear (1182) and, thus, the bearing nut (150) in the first rotational direction to drive axial extension of the extendable plate (130) from the housing (114); and wherein the first and second bevel gears (1182, 1194) are configured to engage one another in substantially perpendicular orientation relative to one another.

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