Intervertebral implant inserter tool

In accordance with one aspect of disclosure, an inserter tool is provided for an elongate intervertebral implant. The inserter tool includes a body and a distal end portion of the body configured to be connected to the elongate intervertebral implant to orient the elongate intervertebral implant so that a longitudinal axis thereof extends in a predetermined direction. The inserter tool includes an offset member extending from the body. The offset member has an impact surface support portion spaced apart from the body and configured to position an impact surface in alignment with the implant longitudinal axis to permit the impact surface to receive an impact force directed in the predetermined direction.

FIELD

This disclosure relates to surgical instruments and, more specifically, inserter tools for inserting implants into spaces between vertebrae.

BACKGROUND

Some spinal surgeries involve positioning an implant between vertebrae of a patient to stabilize the vertebrae. These types of surgeries may involve removing a portion of an annulus or the entirety of an annulus and a disc between the vertebrae and inserting one or more implants into the area previously occupied by the now-removed annulus or portion thereof. The implant may be advanced into the space between vertebrae using various approaches, such as anterior, posterior, or lateral approaches. Lateral or anterior approaches may be desirable in some situations because these approaches avoid the processes and lamina of the vertebrae.

However, utilizing a lateral approach for vertebrae in the lower lumbar region, such as the L4 and L5 vertebrae, is complicated by the patient's ilium or hip bone. In order to position an implant between the L4 and L5 vertebrae, the surgeon connects the implant to an inserter tool and advances the implant into a retracted incision formed in the patent along a path that avoids the ilium. This path is somewhat contorted, because the implant travels over the iliac crest and toward the spine.

Surgeons often select implants that have a height greater than the distance between the vertebrae so that the implant is compressed between the vertebrae when positioned in the intervertebral space. This compression may be utilized to improve the strength of the vertebral/implant construct and encourage bone growth. Due to the taller height of the implant, force is required to urge the vertebrae apart and advance the implant into the intervertebral space. A surgeon may apply the required force to the implant by tapping on a proximal end of the inserter tool using a hammer.

Some traditional intervertebral implants are made by machining a block of surgical-grade polyetheretherketone (PEEK) into the desired shape. These PEEK implants are rigid and readily resist impacts from a hammer. In contrast, some intervertebral implants are made using an additive manufacturing process that involves laser sintering PEEK or polyetherketoneketone (PEKK) particles into the desired implant shape. While these materials have a high compressive strength, the materials may have lower tensile properties.

Inserter tools are known that orient an implant at an oblique angle relative to a shaft of the inserter tool. The angle between the shaft and the implant permits the surgeon to direct the implant posteriorly into the intervertebral space while the shaft extends up and over the iliac crest. The inserter tool has a surface longitudinally aligned with the inserter tool shaft that may be struck with a hammer to drive the implant held by the inserter tool into an intervertebral space. When a surgeon strikes the inserter tool with a hammer, the inserter tool transfers the impact to the implant at the connection between the inserter tool and the implant. Traditional PEEK implants are sufficiently rigid to resist impacts typically applied by surgeons to advance the implants between vertebrae. However, some implants made using additive manufacturing that connect to conventional inserter tools are unable to withstand hammer impacts against the inserter tool. This issue is magnified by inserter tools having an oblique angle between the implant and the inserter tool shaft, which imparts a moment on the proximal end of the implant held by the inserter tool.

SUMMARY

In accordance to one aspect of the present disclosure, an inserter tool is provided for an elongate intervertebral implant. The inserter tool includes a body and a distal end portion of the body. The distal end portion is configured to be connected to the implant to orient the implant so that a longitudinal axis thereof extends in a predetermined direction. The inserter tool further includes an offset member extending from the body and an impact surface support portion of the offset member spaced apart from the body. The impact surface support portion is configured to position an impact surface in alignment with the implant longitudinal axis to permit the impact surface to receive an impact force directed in the predetermined direction. In this manner, the inserter tool permits an impact force to be transferred to the implant along the longitudinal axis thereof which minimizes the moment the inserter tool applies to a proximal end portion of the implant. By minimizing the moment, the proximal end portion of the implant is loaded in a compressive manner by the impact force rather than the proximal end portion being placed in tension and/or shear. This positions the implant, especially implants made using additive manufacturing techniques, to absorb the impact forces without disconnecting from the inserter tool.

In accordance with another aspect of the present disclosure, an inserter tool is provided for an intervertebral implant. The inserter tool includes an offset member, an elongate shaft having a proximal portion connected to the offset member, a distal portion opposite the proximal portion, and a longitudinal axis extending therebetween. The offset member has an impact surface spaced laterally from the longitudinal axis and on one lateral side thereof. The elongate shaft distal portion has a pair of arms with an unlocked configuration that permits the arms to be connected to the intervertebral implant and a locked configuration that secures the arms to the intervertebral implant. Each arm has a distal gripping portion extending obliquely to the longitudinal axis of the elongate shaft on an opposite lateral side of the longitudinal axis from the impact surface portion. The distal gripping portions of the arms are configured to orient the intervertebral implant so that the implant extends obliquely to the longitudinal axis of the elongate shaft on the opposite lateral side of the longitudinal axis. By positioning the impact surface support portion and the arm distal gripping portion on opposite lateral sides of the longitudinal axis, when an impact force is imparted to the impact surface support portion, the offset member and the elongate shaft may transfer the impact force around a patient's iliac crest, down into the pelvic area of the patient, and against the implant to advance the implant into the intervertebral space.

In accordance with another aspect of the current disclosure, an inserter tool is provided for an intervertebral implant and includes an elongate shaft comprising an outer sleeve and an inner shaft. The inserter tool includes a pair of arms associated with at least one of the outer sleeve and the inner shaft, the arms are resiliently biased apart and configured to engage the intervertebral implant. The inserter tool further includes a proximal actuator configured to shift the inner shaft and the outer sleeve relative to one another in a locking direction to urge the arms together against the resilient bias thereof and cause the arms to clamp a portion of the intervertebral implant therebetween. The actuator is further configured to shift the inner shaft and the outer sleeve relative to one another in an opposite, unlocking direction. The shifting of the inner shaft and outer sleeve relative to each other in the unlocking direction permits the resilient bias of the arms to separate the arms and release the implant portion. Upon the resilient bias of the arms being insufficient to separate the arms and release the implant portion, the outer sleeve and the inner shaft include cam surfaces configured to engage and separate the arms with shifting of the inner shaft and outer sleeve relative to each other in the unlocking direction.

DETAILED DESCRIPTION

With reference toFIGS.1and2, an inserter tool10is provided that includes a body12having a housing14and an offset member, such as a handle16. The body12may have a generally L-shape with a gap13that may receive an ilium of a patient so that the handle16is on a laterally outer side of the ilium while the housing12extends into the patient inferiorly along the opposite, inner side of the ilium. The body12may thereby positioned to extend around the iliac crest of a patient. The inserter tool10has a distal end portion18configured to be releasably connected to an implant20. The inserter tool10includes a shaft15sized to position a proximal end portion17of the inserter tool10outside of a patient while the distal end portion18is positioned adjacent vertebral bones of the patient. The inserter tool10has an actuator22that may be operated to shift the distal end portion18from a release or open configuration that permits the distal end portion18to be connected to the implant20to a locked or closed configuration that secures the implant20to the distal end portion18. In one embodiment, the distal end portion18includes arms44configured to clamp the implant20therebetween with the distal end portion18in the open configuration thereof.

The handle16has a base or receiving portion24mounted to the housing14and a free end portion, such as an impact surface support portion26, spaced from the housing14. The impact surface support portion26positions an impact surface, such as a surface28of a force imparting tool30, to be intersected by an inserter axis32. The inserter axis32operates as a virtual load path along which impacts against the impact surface28are transferred to the implant20. The inserter axis32is coaxially aligned with a central, longitudinal axis34of the implant20. The distal end portion18positions the implant20so that the implant axis34extends at an angle36relative to a longitudinal axis38of the housing14(seeFIG.2). The angle36may be in the range of, for example, approximately 1 degree to approximately 40 degrees, such as approximately 5 degrees to approximately 20 degrees, such as approximately 15 degrees.

The handle16and housing14are rigidly joined so that an impact force in direction40against the impact surface28is transmitted through the handle16, the housing14, and to the arms44gripping the implant20. Because the impact force direction40is aligned with the inserter axis32and the implant longitudinal axis34extending therealong, the impact force40is imparted to the implant20without a lateral offset. Because there is no lateral offset, the impact force in direction40does not generate a bending moment about a proximal end portion46of the implant20, such as in direction48. Rather, the impact force in direction40is translated into the implant20to drive a distal end portion49linearly into an intervertebral space. The linear application of force to the implant20in direction40against the impact surface28applies a compressive load to the implant20, rather than a bending or shear load. The implant20may be made using an additive manufacturing process and may be more brittle than a conventional implant made by machining the implant from a block of PEEK. The inserter tool10transfers loading in a compressive manner to the implant20, which the implant20is better able to handle, than bending which may be imparted by a conventional inserter tool. Further, the impact force in direction40may drive the distal end portion49against a surface50, such as surfaces of vertebrae on opposite sides of an intervertebral space, in a direction normal to the surface50. This straightforward or longitudinal application of force resists shifting of the distal end portion49in directions52,54as impacts are directed in directions40against the impact surface28. By applying force in the longitudinal direction, the surgeon has improved control over driving the implant20into an intervertebral space with minimal shifting in directions52,54.

RegardingFIG.2, the longitudinal axis38of the housing14extends at an angle39relative to the inserter tool axis32. Further, the arms44include gripping portions190that extend obliquely, such as at an angle192, relative to the longitudinal axis38. The angle192may be in the range of, for example, approximately 1 degree to approximately 40 degrees, such as approximately 5 degrees to approximately 20 degrees, such as 15 degrees. The handle16extends along a support axis194and may be elongated along the axis194. The loop portion68of the handle16positions the impact surface support portion26to extend at an angle198relative to the axis194. In one embodiment, the angle198is the same as the angle192. The gripping portions190position the implant20obliquely relative to the shaft15on an opposite side of the axis38from the impact surface28. By positioning the implant20and impact surface28on opposite sides of the longitudinal axis38, the handle16and the shaft15permit a surgeon to transfer an impact force up and around a patient's iliac crest, down into the pelvic area of the patient, and against the implant20to advance the implant into an intervertebral space.

With reference toFIGS.1and2, the force imparting tool30may be a T-handle60that is connected to the handle16via a releasable connection62. The force imparting tool30may take other forms, such as a slap hammer. The releasable connection62may include, for example, a Hudson connector. In one embodiment, the releasable connection62includes a male connector64that is mounted to the handle16. RegardingFIGS.2and3, the handle16includes an elongate gripping portion66and a loop portion68extending about a through opening70. The male connector64includes a body72, a connector fastener74, and a connector member76that are secured to the handle16. The connector member76may include a projection78having a non-circular shape, such as a square. The projection78mates with the opening70of the handle16, which may be non-circular, such as a square. The body72of the male connector64also includes a projection82that may have a non-circular cross section. In one approach, the projections78,82and opening70have a mating square arrangement that resists turning of the connector64once installed. The connector fastener74has a threaded shank75that engages a threaded bore of the body72. The connector fastener74rigidly clamps the loop portion68of the handle16between the connector member76and the body72of the male connector64. The rigid connection between the male connectors64and the handle16transfers impacts from the impact surface28to the handle16.

With reference toFIGS.2and3, the housing14includes an outer sleeve90having a flange92and a locking member, such as a nut94. The outer sleeve90has a locking portion96configured to engage the nut94. In one embodiment, the locking portion96has radially outer threads that engage radially inner threads98of the nut94. The outer sleeve90further includes a mounting portion100that extends through a through opening102of the handle16. During assembly of the inserter tool10, the nut94is threadingly engaged with the locking portion96of the outer sleeve90to clamp the receiving portion24of the handle16between the flange92and the nut94. The inserter tool10further includes a locking member, such as a pin374, that fixes the nut94against loosening movement relative to the outer sleeve90. In one embodiment, the pin374extends through one of the holes372of the nut94and into a pocket370of the handle16. The components of the inserter tool10may be made from metallic and/or plastic materials that are sufficiently strong to withstand loading applied during an implant installation. The components may also be made of materials that may be cleaned using an autoclave or gamma radiation, as some examples. For example, the sleeve90and nut94may be made of a stainless steel and the pin374may be made of a hardened stainless steel to resist the shear loading applied to the pin374by the sleeve90and the nut94.

RegardingFIGS.3and4, the body12(seeFIG.1) further includes an inner shaft104that is slidably received in the outer sleeve90. To reconfigure the distal end portion18from an open configuration to a closed configuration or vice versa, the actuator22in one embodiment includes a knob assembly110having a knob231that is turned in a direction111to draw the inner shaft104in proximal direction112and reconfigures the distal end portion18to a closed configuration as shown inFIG.6. The movement of the inner shaft104in direction112causes cam surfaces114,116(seeFIG.12) of the arms44to cammingly engage surfaces118,120of the sleeve90, which shifts the arms44together and clamps a proximal portion122of the implant20therebetween. Once the arms44have shifted proximally sufficiently far so that lands130,132are abutting interference surfaces134,136, the land surfaces130,132have a distance138therebetween that is larger than a distance between the interference surfaces134,136. This creates an interference fit between the arms44and the sleeve90and fixes the arms44at a longitudinal position relative to the sleeve90and locks the arms44onto the implant20. In another embodiment, the outer sleeve90may shift along the inner shaft104.

With reference toFIG.4, turning of the knob231in direction150shifts the inner shaft104in distal direction152and shifts the distal end portion18to an open configuration as shown inFIG.5. The inner shaft104includes a resilient fork portion154(seeFIG.3) which includes the arms44. The resiliency of the fork portion154urges the arms44apart to the open configuration as the lands130,132are shifted distally in direction152away from the interfering position with the interference positions134,136of the sleeve90. In some instances, the resiliency of the fork portion154is sufficient to disengage protrusions160(seeFIG.12) of the arms44from pockets162of the implant20. In these situations, the inserter tool10may then be removed from the surgical site.

With reference toFIGS.2and4, the inserter tool10may be readily disassembled for cleaning. For example, the inserter tool10may have a release mechanism170that selectively limits how far the inner shaft140may shift in direction152. In one embodiment, the release mechanism170includes a detent member, such as a button172, received at least partially in a release compartment174of the housing14. As discussed in greater detail below with respect toFIGS.7and8, the button172may be pressed in direction175to shift the button172from a blocking position where the button172limits longitudinal movement of the inner shaft104in distal direction152to a clearance position where the button172permits shifting of the inner shaft104in the distal direction152to permit removal of the inner shaft104from the sleeve90.

With reference toFIG.3, the inner shaft104may include the resilient fork portion154and a drive portion220. The drive portion220may have a pin222that is received in a socket224of the resilient fork portion154. The drive portion220and resilient fork portion154may be welded together and/or joined using a fastener. In another embodiment, the inner shaft104has a unitary, one-piece construction including the resilient fork portion154and the drive portion220.

The drive portion220includes a reduced diameter portion226, a shoulder228, and a threaded portion230. The knob231of the knob assembly110includes a drive portion232(seeFIG.7) that cooperates with the inner shaft104to drive the inner shaft104in proximal direction112or distal direction152with operation of the knob231. In one embodiment, the knob231includes a bore234, which may be a blind bore or a through bore, with threads236that engage threads238of the threaded portion230of the inner shaft104. The threads236,238may be ACME threads. The engaged ACME threads provide a mechanical advantage to a surgeon as the surgeon turns the knob231to shift the inner shaft104in directions112,152. In some embodiments, ACME threads are selected to permit farther shifting of the inner shaft104in directions112,152for a given turn of the knob231than would be obtained using standard machine threads.

RegardingFIGS.7and8, to assemble the inner shaft104and the outer sleeve90, the button172is pressed radially inward in direction175from the blocking position ofFIG.7into the release position ofFIG.8. Next, the threaded portion230of the inner shaft104is advanced in the proximal direction112into a throughbore242of the sleeve90. The threaded portion230of the inner shaft104is advanced in proximal direction112through a through opening246of the button172until the threaded portion230extends proximally outward from a support portion310(seeFIGS.3and7) of the sleeve90and the reduced diameter portion226of the inner shaft104is positioned in the button through opening246(seeFIG.8). With the threaded portion230of the inner shaft104extending proximally of the sleeve support portion310, the support portion310and threaded portion230may be advanced through the through opening102(seeFIG.3) of the handle16and the nut94threaded onto the locking portion96of the sleeve90. As discussed in greater detail below, the nut94is tightened to clamp the handle16between the nut94and the flange92of the sleeve90and fixed in position by the pin374.

RegardingFIG.3, the button172includes an elongated slot250that receives a portion of an alignment member, such as a dog point screw256, that extends through an opening258of the sleeve90. The release mechanism170includes a biasing member, such as a spring260, which may be a wave spring, that is received in the opening244and biases the button172toward the interference or blocking position thereof.

With reference toFIG.7, the release compartment174includes a spring recess270having a spring seat272that supports the lower end of the spring260. The button172includes a locator pin274that extends and keeps the spring260in position between the button172and the seat272. The button172has a stop, such as a projection276, that is axially aligned with a radially extending surface278of the shoulder228. With the button172in the blocking position, the user turning the knob231to shift the inner shaft104in distal direction152would be limited by the contact between the projection276of the button172and the surface278of the inner shaft shoulder228. In this manner, the button172inhibits the user from unintentionally disassembling the inner shaft104when the user is intending to shift the inner shaft104distally in direction152to disengage the arms44from the implant20.

With reference toFIG.8, the user may press the button172in direction175to shift the button172to the clearance position thereof such that there is a radial clearance distance292between the shoulder228and the projection276. With the projection276in clearance with the shoulder228, the user may turn the knob231and use the threaded engagement between the knob231and the inner shaft104to drive the inner shaft104distally in direction152until the inner shaft104is disconnected from the knob231. At this point, the user may withdraw the inner shaft104from the sleeve90.

With reference toFIG.3, the knob assembly110is rotatably captured on the sleeve90so that the knob231may be turned relative to the sleeve90to shift the inner shaft104in the proximal or distal directions112,152via the engagement between the threads236,238of the inner shaft104and the knob231. In one embodiment, the knob assembly110includes a knob cap300having threads302that are engaged with threads304of the knob231. The knob cap300and knob231are connected together around a washer306that is welded to the support portion310of the sleeve90. In another embodiment, the washer306is connected to the support portion310via a pair of pins extending like chords through holes in the washer306and received in an annular groove in the support portion310. The knob assembly110includes bushings312,314that contact the washer306and permit turning of the knob231and knob cap300while reducing friction between the knob cap300and the knob231. The bushings312,314may be made of a plastic, such as rayon, and the washer306, knob231, and knob cap300may be made of one or more metallic materials, such as stainless steel and/or titanium.

More specifically and with reference toFIG.7, the knob cap300has a collar320with an annular surface322facing a distal surface324of the bushing312. Likewise, the knob231includes an annular wall326extending about the bore234and having a distal annular surface340facing a proximal surface342of the bushing314. When the knob231is turned in direction111(seeFIG.4), the surface340of the knob231is pressed in distal direction152against the surface342of the bushing314which, in turn, presses a distal surface350of the bushing314against a proximal surface352of the washer306. The engagement between threads236,238of the inner shaft104and the knob231thereby transfers turning of the knob cap300in direction111into linear movement of the inner shaft104in the proximal direction112.

Conversely, when the knob231is turned in direction150(seeFIG.4), a surface322of the knob cap collar320presses in proximal direction112against the distal surface324of the bushing312. This presses a proximal surface360of the bushing312against a distal surface362of the washer306. The threaded engagement between the knob231and the inner shaft104thereby transfers turning of the knob cap300in direction150into linear movement of the inner shaft104in the distal direction152. In this way, the bushings312,314reduce friction and make it easier for a surgeon to turn the knob231and shift the arms44between open and closed positions.

With reference toFIG.3, the handle16, nut94and sleeve90are configured to provide rigidity against rotation and bending of the handle16relative to the sleeve90. More specifically, the receiving portion24of the handle16includes one or more pockets370about the through opening102. The pockets370may be in communication with the through opening102. The nut94includes one or more holes372about the opening98. The pin374is advanced through one of the holes372and into one of the pockets370once the nut94has been tightened down to lock the relative rotation positions of the sleeve90and the nut94. The pin374may be welded to the nut94and/or the handle16to fix the pin374in position.

With reference toFIG.10, the nut94is configured so that there is only one aligned hole372of the nut94and one pocket370of the handle16at a given rotary position of the nut94. As the nut94is tightened, the aligned hole372and pocket370will change to another hole372and pocket370and the remaining holes372will be mis-aligned. The sequential alignment of only one hole372at a time with one pocket370permits a manufacturer to specify that the pin374should be inserted through a particular hole372and into the aligned pocket370and, if the pin374is so inserted, the torque experienced by the nut94will be the torque dictated by the position of the nut94. This permits a manufacturer to ensure the nut94has been torqued down to a predetermined torque. In other words, a user would be unable to insert the pin374through the designated hole372and into the associated pocket370until the nut94has been turned sufficiently far to align the hole372with the associated pocket370.

Each pocket370includes a pair of walls380,382with side surfaces384that may be curved to complement an outer surface388of the pin374. As shown inFIG.10, the holes372are slightly mis-aligned so that the nut94must be slightly over-tightened in order to fully align one of the holes372with one of the pockets370and permit the pin374to be inserted through the aligned hole372and pocket370. Once the pin374has been inserted, the nut94needs to turn in direction386to loosen from the sleeve90. The outer surface388of the pin374is engaged with a side surface384A of a wall380A due to the over-tightening of the nut94. This engagement places the pin374in shear. The pin374is selected from a material, such as stainless steel, sufficient to resist the shear loading and inhibit relative turning of the nut94in direction386. In this manner, the wall380A applies a reaction force in direction390that resists movement of the pin374in direction386and the nut94and loosening of the nut94. The nut94thereby securely maintains flange92of the sleeve90and the nut94in a clamping arrangement about the receiving portion24of the handle16.

With reference toFIGS.3and9, the mounting portion100of the sleeve90and the through opening102of the handle16are selected to provide a non-rotatable connection between the mounting portion100and the receiving portion24. In one embodiment, the mounting portion100of the sleeve90has a non-circular cross-section taken perpendicular to the longitudinal axis38, such as a substantially square cross-sectional shape. Likewise, the through opening102of the handle receiving portion24has a non-circular shape, such as a substantially square cross-sectional shape. In the embodiment ofFIG.9, the mounting portion100of the sleeve90includes one or more side portions400having one or more flat surfaces402in confronting relation with one or more flat surfaces404of one or more side walls406of the receiving portion24. The mounting portion100of the sleeve90may include one or more junctures, such as tapered corners410, connecting the flat surfaces402. The receiving portion24may likewise have one or more corner portions412connecting the side walls406and extending about the mounting portion100.

With reference toFIG.11, there is a stop420between the inner shaft104and the sleeve90that limits proximal movement of the inner shaft104beyond the closed position. More specifically, the sleeve90includes an upper wall422and a lower wall424. Each arm44includes a support portion426. The stop420includes surfaces428,430of the arm support portion426and surfaces432,434of the walls422,424. The surfaces428,432and430,434abut to limit proximal movement of the inner shaft104. Further, when the inner shaft104is in the closed position, the engaged surfaces428,432and430,434permits the sleeve90to transmit impact forces in direction152from the handle16directly into the support portion426of the arms428. In this manner, the arms44may have thinner, resilient fork portions435of the arms44(seeFIG.3) that may not need to withstand impact forces.

The support portions426of the arms44together define a socket440that receives a boss442of the implant20. The engagement between the boss442and the socket440increases the length of the engagement between the arms44and implant20along the longitudinal axis38of the implant20. The increased longitudinal engagement strengthens the connection between the inserter tool20and the implant10against bending moments applied by the surgeon as the surgeon moves the inserter tool10in cephalad/caudal directions while maneuvering the implant20into an intervertebral space.

With reference toFIGS.13-15, in some circumstances, the resilient properties of the fork portion154may be insufficient to separate the gripping portions190of the arms44from an implant20to release the implant20. For example, a surgeon may form an opening in an annulus for receiving the implant20that is only as wide as the implant20and does not provide sufficient clearance for the gripping portions190to laterally disengage from the implant20. To provide mechanical separation of the arms44, the inserter tool10includes a cam follower, such as a pin450that rides along a cam, such as a cam surface460of a slot452of the sleeve90. In one embodiment, each arm44has a pin450that rides in a respective slot452. Each slot452includes an end454, a longitudinal portion456, and a transverse portion458. The cam surface460of each slot452extends along an axis462at an angle464relative to the longitudinal axis38. The angle464may be in the range of, for example, approximately 20 degrees to approximately 50 degrees, such as approximately 40 degrees.

Initially, inFIG.13, the inner shaft104is shown in the closed position with the arms44held together by the sleeve90. InFIG.14, the user has turned the knob231to shift the inner shaft104distally in direction152. Due to the presence of tissue resisting lateral expansion of the arms44, the pins450are pressed against the cam surfaces460of the sleeve90which cams the arms44apart in lateral directions470,472. InFIG.15, the user has shifted the inner shaft104to the open position and the arms44have disengaged from the implant20.

With reference toFIG.16, an inserter tool500is shown that is similar in many respects to the inserter tool10discussed above such that differences between the two will be highlighted. The inserter tool500includes a shaft504and a handle506. The inserter tool500has a body502that includes a housing508with a sleeve510and a knob housing portion512. The inserter tool500has a longitudinal tool axis514that is coaxially aligned with a longitudinal axis516of an implant518when the inserter tool500is connected to the implant518. The inserter tool500includes an actuator, such as a knob520, that is operated to shift a distal end portion522of the inserter tool500from an unlocked or open configuration that permits the implant518to be connected to the inserter tool500to a locked or closed configuration that secures the implant518to the inserter tool500. The inserter tool500includes an inner shaft524(seeFIG.17) and a release mechanism526for selectively permitting removal of the inner shaft524from within the sleeve510. RegardingFIG.17, the release mechanism526includes a blocking body, such as a button530, a spring532, and a retainer534. The retainer534keeps the button530within a release compartment536of the housing508. The release mechanism526operates in a manner substantially similar to the release mechanism170discussed above. For example, the button530may contact a collar538of the inner shaft524to limit movement of the inner shaft524in a distal direction540.

With reference toFIGS.17and18, the inner shaft524includes a connecting portion550having a flat552and a hole554that receives a body572of a pin570. The body570of the pin570also extends through a hole566of a link564. The pin570pivotally connects the link564to the inner shaft connecting portion550. The pin570further has a neck568that extends in an arcuate elongated path, such as slot580, of a movable gripping body582and a head574received in an upper portion576of the slot580. In one embodiment, the neck568and head574generally do not contact sides577,579of the slot580as the distal end portion522is shifted between open and closed configurations. In other embodiments, the neck568and/or the head574may contact one or more sides577,579of the slot580.

At an opposite end of the link564from the pin570, the distal end portion522includes a pin558. The pin558has a lower portion569received in a hole562of the link564and an upper portion556received in a hole586of the gripping body582. The pin558is configured to pivotally connect the link564to the gripping body582.

Returning toFIG.17, the sleeve510includes a guide portion620that includes the arm612, a guide member622, and a land624that supports and guides the gripping body582as the gripping body582shifts between open and closed positions.

At a proximal end portion630of the housing508, there is an opening632that receives the knob520and a flared portion634from which a receiving portion636projects proximally. The inner shaft524includes a threaded portion640that engages threads of an inner bore642of the knob520. Thus, turning the knob520in first direction causes the inner shaft524to shift proximally in direction610whereas turning the knob520in a second direction causes the inner shaft524to shift distally in the direction540. The inserter tool500may include washers704,706that separate the knob520and the housing508that reduces wear between the knob520and housing508and makes turning of the knob520easier.

The inserter tool500also includes an impact shaft650having an impact surface652for receiving impacts, such as from a hammer, to advance the implant518into an intervertebral space. The impact shaft650includes a support portion654that extends through a through opening656of the housing508and into a proximal end of the bore642of the knob520. During assembly of the inserter tool500, the support portion654is advanced distally through a through bore666of the handle668and into the through opening656of the housing508. The support portion654rotatably supports the proximal end of the knob520while the threaded portion640of the inner shaft524rotatably supports an opposite end of the knob520. The impact shaft650has a threaded portion660that is engaged with internal threads of the receiving portion636of the housing508to secure the impact shaft650to the housing508. Additionally or alternatively, the impact shaft650may be welded, epoxied, and/or secured using one or more fasteners to the housing508. The impact shaft650further includes a shoulder662that seats against an end surface664of the receiving portion636. The impact shaft650includes a frustoconical portion670that mates with a similarly configured receptacle of a proximal end of the handle668.

RegardingFIG.17, the handle668includes a socket676that fits over the receiving portion636of the housing508. The socket676may be configured to mate with the receiving portion636to form a non-rotatable connection therebetween. In one approach, the receiving portion636includes one or more flats680that abut against corresponding flats of the socket676to resist rotation of the handle668relative to the housing508.

RegardingFIGS.17and19, the handle668may have a core690made of a rigid material that may be light and strong, such as aluminum, and an outer layer692, such as silicone, that is easily gripped by a surgeon. When an impact is applied in direction540against the impact surface652of the impact shaft650, the shoulder662abuts the end surface664of the housing508and transmits the impact to the housing508. The housing508in turn transmits the impact force to the sleeve510and the gripping body582. The sleeve510and gripping body582apply the impact force against the implant518.

With reference toFIG.20, the implant518includes a leading end portion720and a trailing end portion722with the longitudinal axis516extending therebetween. The trailing end portion722includes a pair of transversely extending rear walls724,725and a rear wall726. The sleeve510includes the arm612and the gripping body582includes an arm700. The arms621,700include walls730,732that are complementary to the walls724,725. The walls730,732support and resist turning of the implant518relative to the inserter tool500.

With reference toFIGS.20and23, the distal end portion522of the inserter tool500includes a slide connection740between the gripping body582and the sleeve510that guides the gripping body582along a predetermined path relative to the guide portion620of the sleeve510. In one embodiment, the slide connection740includes the guide member622(seeFIG.23) of the sleeve guide portion620that extends transversely relative to the longitudinal axis514and into a slot744of the gripping body582. The guide member622includes opposite surfaces746,748that permit surfaces750,752of the gripping body582to slide therealong. In one embodiment, the surfaces746,750and748,752are flat, confronting surfaces.

The slide connection740may also include walls752,754(seeFIG.20) of sleeve guide portion620having inclined surfaces756,758that each extend at an angle760relative to the longitudinal axis514. The angle760may be in the range of, for example, approximately 30 to approximately 90 degrees, such as approximately 70 degrees. The gripping body582likewise has walls762,764with surfaces766,768that slide along the inclined surfaces756,758of the sleeve guide portion620. In one embodiment, the surfaces756,766and758,768include abutting flat portions.

The sliding contact between the gripping body582, the guide member622, and the walls752,754restrict movement of the gripping body582to a linear movement in a direction780toward an open position or direction782toward a closed position.

With reference toFIG.21, the distal end portion522of the inserter tool500includes a stop800that limits movement of the gripping body582in direction782to a fully closed position. In the fully closed position, the gripping body582is farther in direction782beyond the closed position of the gripping body582. The presence of the implant518limits movement of the gripping body582to the closed position but, when the implant518is removed from the inserter tool500, the gripping body582may be shifted to the fully closed position. Because the fully closed position is beyond the closed direction in direction782, the distance between the closed and fully closed positions permits the gripping body582to securely clamp the implant518between the arms612,700while taking up any variation in tolerances of the geometry of the implant518.

In one embodiment, the stop800includes a wall802of the guide portion620having a surface803that abuts and limits movement of a surface804of a wall806of the gripping body582in the closing direction782. Conversely, the inserter tool500has a hard stop to limit shifting of the gripping body582in the opening direction780by way of the collar538(seeFIG.17) contacting the button530when the button is in a blocking position. In the blocking position, the button530has a portion that is an axially overlapping relation with the collar538and inhibits shifting of the inner shaft524in distal direction540beyond a predetermined position.

RegardingFIGS.20and21, the gripping body582includes a pair of central walls810,812facing and spaced from the rear wall726of the implant518. Further, the walls730,732of the arms612,700contact the walls724,725of the implant518. The abutting walls730,732and the walls724,725, of the inserter tool500of the implant518transfer impacts from the impact surface652of the inserter tool500to the implant518. Further, the contact between the walls730,732of the inserter tool500and the walls724,725of the implant518evenly distributes the impact forces around the trailing end portion722of the implant518. This provides a durable connection between the implant518and the inserter tool500.

With reference toFIGS.21and23, the arms612,700include fingers820,822that fit into undercuts824,826(seeFIG.30) of the implant518. RegardingFIG.23, each finger820,822includes a surface828extending at an acute angle830relative to a surface832of the adjacent wall730,732. This forms an undercut834that receives a lip750(seeFIG.30) of the implant518when the fingers820,822are received in the undercuts824,826. The overlapping engagement between the fingers820,822and the lips750,752resist axial separation of the implant518from the inserter tool500.

With respect toFIG.24, the guide portion620of the sleeve510includes the land624that supports an inner surface852(seeFIG.21) of the gripping body582. The movement of the pin558applies a force generally in direction854,856to the gripping body582depending on whether the inner shaft524is shifted in direction540or610.

With reference toFIGS.25A-28, the distal end portion522of the inserter tool500is shown inFIG.25Ain a removal configuration. The user has pressed the button530to position the button530in clearance with the collar538of the inner shaft524and has turned the knob521to urge the inner shaft524in distal direction540until the pin570is at an end portion870of the slot580. With the pin570at the end portion870, the link564is substantially longitudinally aligned with the connecting portion550of the inner shaft524and received on the flat552of the inner shaft524. In this position, the gripping body582is shifted in direction780to a position wherein the guide member742no longer extends in the slot744. With the guide member742removed from the slot744, the gripping body582and the inner shaft524may be slid off in direction540as shown inFIG.25B.

RegardingFIG.26, the distal end portion522is shown in the open configuration wherein the pin570is at a first portion872of the slot580and the angle594between the longitudinal axes590,592(seeFIG.24) of the link564and the inner shaft524is at a first angle. The implant518may be positioned so that the trailing end portion722thereof is positioned between the arms612,700.

With reference toFIG.27, the user next turns the knob521in the locking direction to shift the inner shaft524proximally in direction610. This causes the pin570to travel to a second position874along the slot580as the angle594between the axes590,592of the link564and the inner shaft524increases from the first angle ofFIG.26. As discussed above, the pin558drives the gripping body582in direction782and reduces the distance between the arms612,700. InFIG.27, the arms612,700are shown in the closed configuration wherein the fingers820,822are positioned to be engaged with the lips750of the implant518and the arms612,700clamp the implant518therebetween.

RegardingFIG.28, the implant518is not present between the arms612,700and the user has turned the knob521in the locking direction to shift the distal end portion522to a fully closed configuration. In the fully closed configuration, the surfaces803,804of the arm612and the gripping body582are engaged to limit further travel of the gripping body582in direction782. In the fully closed position, the fingers820,822of the arms612,700are positioned closer together than the lips750of the implant518would permit. Because the position of the gripping body582when the distal end portion522is in the fully closed configuration is beyond the position of the gripping body582when the distal end portion522is in the closed configuration, the gripping body582may take-up any dimensional variation in the trailing end portion722of the implant518.

With reference toFIGS.29and30, the implant518may be manufactured using an additive manufacturing approach. In one embodiment, the implant518is made of a PEKK or PEEK material that is laser sintered into the shape of the implant518. The implant518includes a body900having an annular wall904extending about a central cavity906. The wall904includes an inner surface910having a plurality of protrusions912that provide additional surface area for bone graft material to engage with. In other embodiments, the implant518may be made using a subtractive manufacturing approach, such as by machining the implant from a block of PEEK, and/or may be molded. In some embodiments, the implant518may be made of a metallic material such as titanium.

The trailing end portion722includes one or more pockets920,922,924for engaging the inserter tool500. The implant518may be provided as a kit including the inserter tool500and an angled inserter tool, such as an angled inserter tool1000discussed below with respect below toFIG.31. Each pocket920,922,924has an outer opening926that opens to an interior of the pocket920,922,924and one or more lips750. The inserter tool500engages the lips750of the pockets920and924. Conversely, the inserter tool1000engages the pockets922,924when the inserter tool1000is positioned to extend to the right side of the implant518as shown inFIG.31or engages the lips570of the pockets920,922when the inserter tool1000is positioned to extend toward the left side of the implant518. The trailing end portion722of the implant518thereby permits different orientations of different tools to be utilized with a single implant518. RegardingFIGS.20and30, the walls724,725,726of the implant518have surfaces950,952,954with the surfaces950,954being oriented at an angle956relative to the surface952, such as in the range of approximately 100 degrees to approximately 175 degrees, such as approximately 160 degrees.

With reference toFIG.31, the inserter tool1000includes a body1002including a shaft1004and a handle1006. The body1002includes a housing1008having a sleeve1009and a distal end portion1010. The inserter tool1000is similar in many respects to the inserter tool500discussed above such that differences between the two will be highlighted.

With reference toFIG.32, the inserter tool1000includes a longitudinal axis1012and the distal end portion1010orients implant518so that the longitudinal axis516thereof extends at an angle1020relative to the longitudinal axis1012of the inserter tool1000. In one embodiment, the angle1020is in the range of, for example, approximately 5 degrees to approximately 40 degrees, such as in the range of approximately 20 degrees to approximately 40 degrees, such as in the approximately 30 degrees.

The orientation of the implant518relative to the shaft1004permits the implant518to be advanced into the patient and avoid tissue of the patient, such as one or more veins, that would obstruct movement of the implant518if the inserter tool500were used. As discussed above, either of the inserter tools500,1000may be connected to the implant518depending on the anatomy of the patient. The ability to select which inserter tool500,1000to utilize with the implant518based on the patient's anatomy provides enhanced flexibility to a surgeon.

RegardingFIGS.32and33, the distal end portion1010includes a movable gripping body1024, a pin1036, and a pin1038.FIG.33shows the distal end portion1010in a closed configuration,FIG.34shows the distal end portion1010in an open configuration, andFIG.35shows the distal end portion1010in a disassembly configuration.

RegardingFIG.32, the gripping body1024is slidably connected to a guide portion1026of the sleeve1009and is shiftable in direction1033to an open position and in direction1032to a closed position. As an inner shaft of the inserter tool1000is shifted in a distal direction1060from an open position to a closed position, the pin1036travels along a slot1042from an open first position1044to a closed second position1046. The pin1036is pivotally connected to an internal link which is in turn pivotally connected to the pin1038. The pins1036,1038and link drive the gripping body1024in a manner similar to the pins558,570and link564discussed above.

RegardingFIG.35, the distal end portion1010has a disassembly configuration wherein the pin1036is at an end1050of the slot1042. With the distal end portion1010in the disassembly configuration, the gripping body1024and the inner shaft of the inserter tool1000may thereby be removed from the sleeve1009.

While there have been illustrated and described particular embodiments of the present invention, it will be appreciated that numerous changes and modifications will occur to those skilled in the art, and it is intended for the present invention to cover all those changes and modifications which fall within the scope of the appended claims. It is intended that the phrase “at least one of” be interpreted in the disjunctive sense. For example, the phrase “at least one of A and B” is intended to encompass only A, only B, or both A and B.