Patent Publication Number: US-2023134792-A1

Title: Expandable implant

Description:
TECHNICAL FIELD 
     The present disclosure is directed to an implant, and more particularly, to an expandable implant. 
     BACKGROUND OF THE DISCLOSURE 
     Conventional corpectomy devices are used to treat conditions, injuries, and diseases that degrade a functioning of the spinal column. Corpectomy devices are typically used to decompress spinal nerves and the spinal cord. 
     Conventional corpectomy devices include expandable corpectomy devices. Such expandable corpectomy devices may use a rack and gear assembly or a turnbuckle or threaded mechanism for expansion. Conventional corpectomy devices that use a rack and gear assembly typically have a single rack and gear, which can lead to the device skewing to one side during expansion. Conventional corpectomy devices that use rack and gear expandable devices may utilize a ratchet or other mechanism to prevent unwanted collapse. However, such conventional corpectomy devices are unable to turn the ratchet off if the device is over-expanded or is to be collapsed for removal or replacement. 
     The exemplary disclosed system and method of the present disclosure is directed to overcoming one or more of the shortcomings set forth above and/or other deficiencies in existing technology. 
     SUMMARY OF THE DISCLOSURE 
     In one exemplary aspect, the present disclosure is directed to an implant. The implant includes a base including an extension arm cavity and a ratchet block cavity that intersects the extension arm cavity, an extension arm that is movably disposed in the extension arm cavity, and a ratchet block that is movably disposed between a first position and a second position in the ratchet block cavity. The ratchet block when disposed in the first position allows movement of the extension arm in an upward direction out of the extension arm cavity and blocks movement of the extension arm in a downward direction into the extension arm cavity. The ratchet block when disposed in the second position allows movement of the extension arm both in the upward direction out of the extension arm cavity and the downward direction into the extension arm cavity. 
     In another aspect, the present disclosure is directed to a method. The method includes providing a base including an extension arm cavity and a ratchet block cavity that intersects the extension arm cavity, movably disposing an extension arm in the extension arm cavity, movably disposing a ratchet block between a first position and a second position in the ratchet block cavity, allowing movement of the extension arm in an upward direction out of the extension arm cavity and blocking movement of the extension arm in a downward direction into the extension arm cavity by disposing the ratchet block in the first position, and allowing movement of the extension arm both in the upward direction out of the extension arm cavity and the downward direction into the extension arm cavity by disposing the ratchet block in the second position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Accompanying this written specification is a collection of drawings of exemplary embodiments of the present disclosure. One of ordinary skill in the art would appreciate that these are merely exemplary embodiments, and additional and alternative embodiments may exist and still within the spirit of the disclosure as described herein. 
         FIG.  1    illustrates a perspective view of an exemplary device in collapsed position, with ratchet in a first position (e.g., prevention position); 
         FIG.  2    illustrates an exploded view of the exemplary disclosed device; 
         FIG.  3    illustrates a perspective view of the exemplary disclosed device in expanded position, with ratchet in the first position (e.g., prevention position); 
         FIG.  4    illustrates a perspective view of the exemplary disclosed device in expanded position, with ratchet in a second position (e.g., non-prevention position); 
         FIG.  5    illustrates an anterior view of the exemplary disclosed device in collapsed position; 
         FIG.  6    illustrates an anterior view of the exemplary disclosed device in expanded position; 
         FIG.  7    illustrates a left lateral view of the exemplary disclosed device in collapsed position; 
         FIG.  8    illustrates a left lateral view of the exemplary disclosed device in expanded position; 
         FIG.  9    illustrates a posterior view of the exemplary disclosed device in collapsed position; 
         FIG.  10    illustrates a posterior view of the exemplary disclosed device in expanded position; 
         FIG.  11    illustrates a right lateral view of the exemplary disclosed device in collapsed position, with ratchet in prevention position; 
         FIG.  12    illustrates a right lateral view of the exemplary disclosed device in expanded position, with ratchet in prevention position; 
         FIG.  13    illustrates a right lateral view of the exemplary disclosed device in expanded position, with ratchet in non-prevention position; and 
         FIG.  14    illustrates a perspective view of another exemplary disclosed device in expanded position, with ratchet in prevention position. 
     
    
    
     DETAILED DESCRIPTION AND INDUSTRIAL APPLICABILITY 
     The exemplary disclosed system, apparatus, and method may include an expandable implant. For example, the exemplary disclosed system, apparatus, and method may be an expandable corpectomy device. In at least some exemplary embodiments, the exemplary disclosed system, apparatus, and method may be an expandable corpectomy device with selectable ratchet. 
     In at least some exemplary embodiments, the exemplary disclosed system, apparatus, and method may be a corpectomy implant that may expand upward utilizing a rack and gear assembly or mechanism. The exemplary disclosed implant may have a ratchet mechanism that may substantially prevent undesirable (e.g., unwanted) collapse of the device after the device has been expanded. The exemplary disclosed ratchet mechanism may be movable to allow for the device to be collapsed if desired, to be repositioned, to alter a final height of the device, and/or to allow for removal of the device. The exemplary disclosed implant may be formed from any suitable material for providing an implant such as, for example, titanium, cobalt chrome, nitinol, stainless steel, tantalum, bioceramic material (e.g., alumina and zirconia), polyetheretherketone, and/or any other suitable materials for providing an implant. 
       FIGS.  1 - 13    illustrate an exemplary embodiment of the exemplary disclosed system, apparatus, and method. An expandable implant  10  may include two main components, a base  20 , and an extension arm  40 . The base  20  may have an internal extension arm cavity  22  within which the extension arm  40  is disposed (e.g., sits). Extension arm  40  may translate upward or superiorly within the extension arm cavity  22 . The extension arm cavity  22  of the base  20  may prevent the extension arm  40  from rotating. 
     The base  20  may be a rectangular cube (e.g., or any other suitable shape) with protrusions such as spikes  21  or any other suitable anti-migration features. Spikes  21  may be disposed on the lower, or inferior, face of base  20 . Spikes  21  may contact or abut (e.g., dig into) a vertebral endplate. The upper, or superior, face of the base  20  may include (e.g., be defined by) an extension arm cavity  22  which may be substantially (e.g., roughly) the same shape and size as the extension arm  40 , allowing the extension arm  40  to slide down into the base  20 . The anterior, or proximal, face of the base  20  may include two apertures (e.g., large holes) on the upper, lateral portions. The first hole, on what may be the implant&#39;s  10  (e.g., and patient&#39;s) left may be a main gear front aperture  23 . Main gear front aperture  23  may be a cylindrical hole that extends (e.g., runs) from the anterior face of the base  20  to the back of the extension arm cavity  22 . Additionally, the main gear front aperture  23  may also intersect the extension arm cavity  22 . A main gear rear aperture  24  may extend along the same axis as the main gear front aperture  23  from the back face of the extension arm cavity  22  to the posterior face of the base  20 . The main gear rear aperture  24  may be slightly smaller in diameter than main gear front aperture  23 . A main gear  50  may fit inside these two main gear apertures  23 ,  24 , allowing the main gear  50  to rotate axially within them. A rear nub  54  of the main gear  50  may fit inside the main gear rear aperture  24  to allow two points of contact for the elongated cylindrical main gear  50 , as well as preventing the main gear  50  from being forced posteriorly. A pair of main gear retaining pin holes  25  may be disposed on the left lateral face of the base  20 . The pair of main gear retaining pin holes  25  may intersect the main gear front aperture  23 . A pair of main gear retaining pins  90  may be inserted into these main gear retaining pin holes  25  and in turn may seat into a retaining pin recess  55  of the main gear  50 , which may prevent main gear  50  from being removed from the base  20 . 
     The main gear  50  may include (e.g., may be defined by) a drive feature  51  disposed on the anterior face, which may allow a user (e.g., a surgeon) to turn the main gear  50 . The main gear  50  may also include (e.g., may be defined by) a set of front gear teeth  52  and rear gear teeth  53 , separated by the retaining pin recess  55 . The rear nub  54  may be disposed at the posterior end of the main gear  50 . The front gear teeth  52  of the main gear  50  may mesh with a front main rack  43  of the extension arm  40 . Likewise, the rear gear teeth  53  of the main gear  50  may mesh with a rear main rack  44  of the extension arm  40 . As the main gear  50  rotates, it may thereby move the extension arm  40  up and down in relation to the base  20 . 
     A ratchet drive aperture  30  may be disposed on the right, upper, lateral portion of the front face of the base  20 . The ratchet drive aperture  30  may extend to and align with a secondary gear aperture  26 . A secondary gear  60  may be inserted through the ratchet drive aperture  30  and inserted into the secondary gear aperture  26 , where the secondary gear  60  may be able to rotate. Both the ratchet drive aperture  30  and the secondary gear aperture  26  may intersect the extension arm cavity  22 . The rear of the secondary gear aperture  26  may narrow to hold a rear nub  62  of the secondary gear  60  and to prevent the secondary gear  60  from being pushed unsuitably (e.g., too far) posteriorly. A secondary gear retaining pin hole  27  may be disposed on the right lateral face of the base  20 . The secondary gear retaining pin hole  27  may intersect the secondary gear aperture  26 . A secondary gear retaining pin  100  may be inserted into the secondary gear retaining pin hole  27  and in turn may seat into a retaining pin groove  63  of the secondary gear  60 , which may prevent the secondary gear  60  from being removed from the base  20 . 
     The secondary gear  60  may include (e.g., may be defined by) a ratchet drive aperture  64  disposed on the anterior face, which may allow a rear nub  83  of a ratchet drive  80  to seat into the secondary gear  60 . The secondary gear  60  may also include (e.g., may be defined by) a set of gear teeth  61 , which may be posterior (e.g., just posterior) of the retaining pin groove  63 . A rear nub  62  may be disposed at the posterior end of the secondary gear  60 . The gear teeth  61  of the secondary gear  60  may mesh with a secondary rack  45  of the extension arm  40 . As the extension arm  40  translates within the base  20 , the extension arm  40  may turn the secondary gear  60 , thereby providing (e.g., ensuring) that the extension arm  40  moves straight. 
     A rectangular ratchet block cavity  28  may be disposed on the right lateral face of the base  20 . The rectangular ratchet block cavity  28  may intersect both the ratchet drive aperture  30  as well as the extension arm cavity  22 . Additionally, a ratchet block retaining pin hole  29 , which may extend posteriorly from the anterior face of the base  20 , parallel to the ratchet drive aperture  30 , may intersect the ratchet block cavity  28 . A ratchet block  70  may be disposed (e.g., may sit) within the ratchet block cavity  28 . The ratchet block  70  may be able to translate anteriorly-posteriorly within the ratchet block cavity  28 . The ratchet block  70  may be held in place by the ratchet drive  80  and a ratchet block retaining pin  120 . The upper portion of the ratchet block  70  may have an aperture including fasteners (e.g., threads  72 ), through which fasteners (e.g., threads  82 ) of the ratchet drive  80  may be received (e.g., may go through). A lower portion of the ratchet block  70  may include (e.g., may be defined by) a ratchet arm  71  and a retaining pin hole  73 . The ratchet block retaining pin  120  may be received by (e.g., may go through) the retaining pin hole  73  of the ratchet block  70 , and may prevent the ratchet block  70  from spinning or rotating as the ratchet drive  80  is turned. For example, as the ratchet drive  80  is turned, the ratchet drive  80  may cause (e.g., may force) the ratchet block  70  to translate within the ratchet block cavity  28 . The ratchet arm  71  of the ratchet block  70  may be a flexible member that is flat on its top, and angled from underneath. The ratchet arm  71  may be formed from any suitable flexible material and/or may be configured to act flexibly (e.g., as a cantilever and/or any other suitable flexible configuration). For example, ratchet arm  71  may be formed from similar material as the exemplary disclosed materials described herein and may be configured to act flexibly (e.g., configured with a cantilever portion). The ratchet arm  71  may interact with a ratchet rack  46  of the extension arm  40  while the ratchet block  70  is in its anterior most position (e.g., as illustrated in the first position or prevention position of the ratchet block  70  in  FIG.  3   ). When the ratchet block  70  is moved to its posterior most position within the ratchet block cavity  28 , the ratchet block  70  may no longer contact (e.g., touch) the ratchet rack  46  of the extension arm  40  (e.g., as illustrated in the second position or non-prevention position of the ratchet block  70  in  FIG.  4   ). Because the teeth of the ratchet rack  46  may be flat on the bottom and angled on the top, the ratchet arm  71  may prevent the extension arm  40  from retracting into the base  20  after it has been expanded, while the ratchet block  70  is in the anterior position. The flat surface of the ratchet arm  71  may abut (e.g., bear) against the flat surface of one of the teeth of the ratchet rack  46  to prevent the extension arm  40  from moving downward into the extension arm cavity  22 . The flexible ratchet arm  71  may flexibly move based on contact between the angled surface of the ratchet arm  71  and the angled surface of one of the teeth of the ratchet rack  46 . For example, an end portion of ratchet arm  71  may engage with (e.g., catch) a tooth of ratchet rack  46 . The extension arm  40  may move upwards (e.g., only move upwards) within the base  20  while the ratchet block  70  is in this anterior or first position. However, when the ratchet block  70  is moved to the posterior or second position, the extension arm  40  may be moved both up and down within the base  20 . The ratchet block  70  may move in a first direction between the first and second position (e.g., as illustrated in  FIGS.  3  and  4   ) that may be perpendicular to the upward and downward direction of the movement of the extension arm  40 . 
     The ratchet drive  80  may extend through the ratchet block  70 . A drive feature  81  may be disposed on the anterior face of the ratchet drive  80 , which may allow a user (e.g., a surgeon) to turn the ratchet drive  80 . A retaining pin groove  84  may be disposed posterior of (e.g., just posterior of) the drive feature  81 . A ratchet drive retaining pin  110 , which may be inserted through a ratchet drive retaining pin hole  31  disposed at (e.g., on) the lateral face of the base  20 , may be disposed within (e.g., may be seated within) the retaining pin groove  84 , thereby substantially preventing (e.g., preventing) the ratchet drive  80  from translating within the base  20 . The threads  82  may be disposed posterior of the retaining pin groove  84 , which may drive the ratchet block  70  forward and backward. The posterior portion of the ratchet drive  80  may include the rear nub  83 , which may be received in (e.g., may seat into) the ratchet drive aperture  64  of the secondary gear  60 . The rear nub  83  may provide rotation contact (e.g., two points of rotation contact) for the ratchet drive  80 , while still allowing the ratchet drive  80  and secondary gear  60  to rotate independently of one another. 
     The lower anterior face of the base  20  may include (e.g., may be defined by) an anterior aperture  33 . As the extension arm  40  is extended upward, the extension arm  40  may vacate the lower portion of the extension arm cavity  22 , creating a void. The anterior aperture  33  may allow a user (e.g., a surgeon) to pack bone graft into this void after the extension arm  40  has been extended, thereby aiding in the fusion during a procedure. The posterior and lateral faces of the base  20  may be solid, or may have windows (e.g., large windows as shown), small holes, or a porous structure  34   a , for example as shown in an implant  10   a  (e.g., including a base  20   a  with porous structure that may be similar to base  20 , and an extension arm  40   a  with porous structure that may be similar to extension arm  40 ) of  FIG.  14   . 
     The extension arm  40  may be an elongated rectangular cube having spikes  41  (e.g., and/or other anti-migration features) disposed on the upper, or superior, face. The spikes  41  may dig into a vertebral endplate. A graft aperture  42  may also extending from the upper face, into the extension arm  40 . Bone graft may be packed into the graft aperture  42 . The left side of the extension arm  40  may include (e.g., may be defined by) the front main rack  43  and the rear main rack  44 . The right side of the extension arm  40  may include (e.g., may be defined by) the secondary rack  45  on the posterior corner and the ratchet rack  46  on the front corner. The anterior, posterior, and lateral faces of the extension arm  40  may be solid, or have windows (e.g., large windows as shown), small holes, or a porous structure  47   a , for example as shown in  FIG.  14   . 
     The exemplary disclosed system, apparatus, and method may be used in any suitable application involving a spinal surgical procedure. For example, the exemplary disclosed system, apparatus, and method may be used in any suitable application involving a corpectomy or a vertebrectomy. The exemplary disclosed system, apparatus, and method may be used in any suitable application involving providing an implant device. The exemplary disclosed system, apparatus, and method may be used in any suitable application involving providing a corpectomy device. 
     A list of exemplary parts of the exemplary disclosed system, apparatus, and method is provided below:
       10 —implant     10   a —second preferred implant     20 —base     20   a —base with porous structure
         21 —spikes     22 —extension arm cavity     23 —main gear front aperture     24 —main gear rear aperture     25 —main gear retaining pin holes     26 —secondary gear aperture     27 —secondary gear retaining pin hole     28 —ratchet block cavity     29 —ratchet block retaining pin hole     30 —ratchet drive aperture     31 —ratchet drive retaining pin hole     32 —inserter/set screw holes     33 —anterior aperture     34   a —porous structure   
         40 —extension arm     40   a —extension arm with porous structure
         41 —spikes     42 —graft aperture     43 —front main rack     44 —rear main rack     45 —secondary rack     46 —ratchet rack     47   a —porous structure   
         50 —main gear
         51 —drive feature     52 —front gear teeth     53 —rear gear teeth     54 —rear nub     55 —retaining pin recess   
         60 —secondary gear
         61 —gear teeth     62 —rear nub     63 —retaining pin groove     64 —ratchet drive aperture   
         70 —ratchet block
         71 —ratchet arm     72 —threads     73 —retaining pin hole   
         80 —ratchet drive
         81 —drive feature     82 —threads     83 —rear nub     84 —retaining pin groove   
         90 —main gear retaining pin     100 —secondary gear retaining pin     110 —ratchet drive retaining pin     120 —ratchet block retaining pin   

     In at least some exemplary embodiments, the exemplary disclosed implant may include a base (e.g., base  20  or base  20   a ) including an extension arm cavity and a ratchet block cavity that intersects the extension arm cavity, an extension arm (e.g., extension arm  40  or extension arm  40   a ) that is movably disposed in the extension arm cavity, and a ratchet block (e.g., ratchet block  70 ) that is movably disposed between a first position and a second position in the ratchet block cavity. The ratchet block when disposed in the first position may allow movement of the extension arm in an upward direction out of the extension arm cavity and may block movement of the extension arm in a downward direction into the extension arm cavity. The ratchet block when disposed in the second position may allow movement of the extension arm both in the upward direction out of the extension arm cavity and the downward direction into the extension arm cavity. The ratchet block may include a flexible ratchet arm and the extension arm may include a ratchet rack. The flexible ratchet arm may be aligned with the ratchet rack when the ratchet block is disposed in the first position. The ratchet rack may include a plurality of teeth, each of the plurality of teeth including a flat surface facing downward into the extension arm cavity and an angled surface facing upward away from the extension arm cavity. The flexible ratchet arm may include a flat surface facing upward away from the extension arm cavity and an angled surface facing downward into the extension arm cavity. The exemplary disclosed implant may also include a ratchet drive that is rotatably received in a ratchet drive aperture of the base and an aperture of the ratchet block. The ratchet drive may include ratchet drive threads that are threadable with ratchet block threads of the aperture of the ratchet block. The ratchet block may translate between the first position and the second position in the ratchet block cavity based on a rotation of the ratchet drive. The exemplary disclosed implant may further include a secondary gear that is rotatably received in a secondary gear aperture of the base that is aligned with the ratchet drive aperture, the secondary gear including a ratchet drive aperture configured to receive a rear nub of the ratchet drive. The secondary gear may include gear teeth that are configured to mesh with a secondary rack of the extension arm. The ratchet drive may rotate independently of the secondary gear. The ratchet block may move in a first direction between the first and second position that is perpendicular to the upward and downward direction of the movement of the extension arm. 
     In at least some exemplary embodiments, the exemplary disclosed method may include providing a base (e.g., base  20  or base  20   a ) including an extension arm cavity and a ratchet block cavity that intersects the extension arm cavity, movably disposing an extension arm (e.g., extension arm  40  or extension arm  40   a ) in the extension arm cavity, movably disposing a ratchet block (e.g., ratchet block  70 ) between a first position and a second position in the ratchet block cavity, allowing movement of the extension arm in an upward direction out of the extension arm cavity and blocking movement of the extension arm in a downward direction into the extension arm cavity by disposing the ratchet block in the first position, and allowing movement of the extension arm both in the upward direction out of the extension arm cavity and the downward direction into the extension arm cavity by disposing the ratchet block in the second position. The exemplary disclosed method may also include rotatably receiving a ratchet drive in a ratchet drive aperture of the base and an aperture of the ratchet block. The exemplary disclosed method may further include translating the ratchet block between the first position and the second position in the ratchet block cavity based on rotating the ratchet drive, which may translate the ratchet block based on ratchet drive threads of the rachet drive being threaded with ratchet block threads of the aperture of the ratchet block. The exemplary disclosed method may also include rotatably receiving a secondary gear in a secondary gear aperture of the base that is aligned with the ratchet drive aperture, and rotating the ratchet drive independently of the secondary gear. Blocking movement of the extension arm in the downward direction into the extension arm cavity by disposing the ratchet block in the first position may include abutting a downward-facing flat surface of a tooth of a ratchet rack of the extension arm against an upward-facing flat surface of a flexible ratchet arm of the ratchet block. 
     In at least some exemplary embodiments, the exemplary disclosed implant may include a base (e.g., base  20  or base  20   a ) including an extension arm cavity and a ratchet block cavity that intersects the extension arm cavity, an extension arm (e.g., extension arm  40  or extension arm  40   a ) that is movably disposed in the extension arm cavity, and a ratchet block (e.g., ratchet block  70 ) that is movably disposed between a first position and a second position in the ratchet block cavity. The ratchet block when disposed in the first position may allow movement of the extension arm in an upward direction out of the extension arm cavity and blocks movement of the extension arm in a downward direction into the extension arm cavity. The ratchet block when disposed in the second position may allow movement of the extension arm both in the upward direction out of the extension arm cavity and the downward direction into the extension arm cavity. The ratchet block may include a flexible ratchet arm. The extension arm may include a ratchet rack. The flexible ratchet arm may be aligned with the ratchet rack when the ratchet block is disposed in the first position. The flexible ratchet arm may include a flat surface facing upward away from the extension arm cavity and an angled surface facing downward into the extension arm cavity. The ratchet rack may include a plurality of teeth, each of the plurality of teeth including a flat surface facing downward into the extension arm cavity and an angled surface facing upward away from the extension arm cavity. The exemplary disclosed implant may also include a first plurality of spikes disposed at an upward-facing surface of the extension arm facing away from the extension arm cavity and a second plurality of spikes disposed at a downward-facing surface of a bottom of the base. 
     The exemplary disclosed system, apparatus, and method may provide an efficient and effective technique for providing for a surgical procedure such as a corpectomy or vertebrectomy procedure. The exemplary disclosed system, apparatus, and method may provide for removing a mechanism of a corpectomy device that prevents collapse when, for example, the corpectomy device is over-expanded or is to be collapsed for removal or replacement. 
     While multiple embodiments are disclosed, still other embodiments of the present disclosure will become apparent to those skilled in the art from this detailed description. There may be aspects of this disclosure that may be practiced without the implementation of some features as they are described. It should be understood that some details have not been described in detail in order to not unnecessarily obscure the focus of the disclosure. The disclosure is capable of myriad modifications in various obvious aspects, all without departing from the spirit and scope of the present disclosure. Accordingly, the drawings and descriptions are to be regarded as illustrative rather than restrictive in nature.