Patent Description:
The invention is directed to a bone screw insertion device as defined in claim <NUM>. Further embodiments of the invention are recited in the dependent claims. The present disclosure relates to a system for treating a bone. The system includes a headless screw and an insertion device. The headless screw extends from a proximal end to a distal end and including a threading extending along an outer surface thereof. The headless screw includes a driving recess extending into the proximal end thereof. The insertion device includes an outer sleeve extending from a proximal end to a distal end and including a channel extending therethrough and a driving member. The driving member extends longitudinally through the channel of the outer sleeve from a proximal end to a distal end. The proximal end of the driving member extends proximally of the proximal end of the outer sleeve to a distal end configured to engage the driving recess of the headless screw to rotationally drive the headless screw into a bone. The outer sleeve is movable relative to the driving member between a first position, in which the distal end of the outer sleeve extends over and covers a proximal portion of the headless screw when the headless screw is engaged with the driving member in the operative configuration, to a second position, in which a distal end of the outer sleeve is longitudinally aligned with a proximal end of the headless screw.

In an embodiment, the headless screw further includes a retaining recess extending distally from the driving recess.

In an embodiment, the insertion device further includes a retaining member extending longitudinally through a channel of the driving member from a proximal end to a distal end configured to engage the retaining recess so that the headless screw is retained on the insertion device during insertion of the headless screw into the bone.

In an embodiment, the retaining recess includes a threading therealong and the distal end of the retaining member is correspondingly threaded so that, rotation of the retaining member about a longitudinal axis thereof relative to the driving member, engages the threading of the retaining member with the threading of the retaining recess to retain the headless screw on the insertion device.

In an embodiment, the proximal end of the retaining member includes a knob extending proximal of the proximal end of the driving member to rotate the retaining member relative to the driving member.

In an embodiment, the outer sleeve includes a locking mechanism for locking the outer sleeve relative to the driving member in one of the first and second positions, the locking mechanism including a locking tab biased toward a locking configuration via a biasing element and a push button compressing the biasing element to move the locking tab toward an unlocked configuration.

In an embodiment, the driving member includes a first groove extending into an outer surface of the driving member so that when the locking tab is received within the first groove the outer sleeve is in the first position relative to driving member, and a second groove extending into the outer surface of the driving member proximal of the first groove so that when the locking tab is received within the second groove the outer sleeve is in the second position relative to the driving member.

In an embodiment, a core diameter of the proximal portion of the headless screw is larger than a core diameter along a remaining portion of the headless screw.

According to the invention, the outer sleeve includes gripping features extending distally from the distal end thereof, the gripping features configured to engage the bone.

In an embodiment, the outer sleeve includes a threading along the distal end thereof configured to engage a corresponding threading along the proximal portion of the headless screw.

In an embodiment, the outer sleeve includes a proximal portion and a distal portion connected to one another via a friction interface, the distal portion being rotatable about a longitudinal axis thereof.

In an embodiment, the proximal portion of the outer sleeve includes a mating feature configured to mate with a corresponding mating feature on the driving member to prevent the proximal portion from rotating relative to the driving member.

In an embodiment, the proximal portion of the outer sleeve includes a depth indicator that indicates a depth to which the headless screw has been inserted into the bone. In addition, the present disclosure relates to a bone screw insertion device. The device includes an outer sleeve extending from a proximal end to a distal end and including a channel extending therethrough and a driving member. The driving member extends longitudinally through the channel of the outer sleeve from a proximal end to a distal end configured to engage a driving recess of a bone screw. The outer sleeve is movable relative to the driving member between a first position in which the distal end of the outer sleeve extends over and covers a proximal portion of a bone screw engaged with the driving member, to a second position in which the distal end of the outer sleeve is longitudinally aligned with a proximal end of a bone screw engaged with the driving member.

In an embodiment, the system further includes a retaining member extending longitudinally through the channel of the driving member from a proximal end to a distal end, the retaining member being configured to releasably engage a retaining recess of a bone screw.

In an embodiment, the distal end of the retaining member is threaded to engage a corresponding threading of the retaining recess.

In an embodiment, the outer sleeve includes a threading along an inner surface of a distal portion thereof configured to engage a corresponding threading along the proximal portion of a headless screw received within the outer sleeve.

In an embodiment, the outer sleeve includes a proximal portion and a distal portion connected to one another via a friction interface, the distal portion of the outer sleeve being rotatable about a longitudinal axis thereof relative to the proximal portion of the outer sleeve.

In an embodiment, the proximal portion of the outer sleeve includes a depth indicator that indicates a depth to which the headless screw engaged to the driving member has been inserted into the bone. Furthermore, the present disclosure relates to a method for implanting a bone screw which includes assembling a headless bone screw with an insertion device by inserting a distal end of a driving member of the insertion device into a correspondingly sized and shaped driving recess of the headless screw; inserting the headless bone screw to a position adjacent to a target area of the bone with the insertion device in a first position with an outer sleeve mounted over the driving member so that a distal end of the outer sleeve extends over and covers a proximal portion of the headless screw; driving the headless bone screw into the bone by rotating the driving member until the distal end of the outer sleeve abuts a near cortex of the bone; drawing the outer sleeve proximally relative to the driving member from the first position to a second position in which a distal face of the outer sleeve is longitudinally aligned with a proximal face of the headless bone screw; and driving the headless bone screw further distally into the bone until the distal end of the outer sleeve contacts the near cortex of the bone, providing tactile feedback to the user that the headless screw is flush with the bone.

In an embodiment, the method further includes retaining the headless bone screw on the insertion device by threadedly engaging a threaded distal portion of a retaining member with a correspondingly threaded retaining recess of the headless bone screw, the retaining member extending longitudinally through the driving member.

In an embodiment, drawing the outer sleeve proximally relative to the driving member from the first position to the second position includes moving a locking mechanism of the outer sleeve from a locked configuration to an unlocked configuration so that a locking tab of the locking mechanism is movable from a first groove along the driving member to a second groove along the driving member.

In an embodiment, the locking tab is biased toward the locked configuration via a biasing.

In an embodiment, moving the locking mechanism from the locked configuration to the unlocked configuration includes pressing a push button to compress the biasing element so that the locking tab is disengaged from the first groove and the outer sleeve is proximally movable along the driving member, the locking tab reverts to the biased configuration to engage the second groove in the second configuration.

In an embodiment, the method further includes removing the insertion device from the implanted headless bone screw by disengaging the threaded distal portion of the retaining member from retaining recess and drawing the insertion device proximally therefrom.

In an embodiment, the method further includes retaining the headless bone screw on the insert device by threadedly engaging the distal end of the outer sleeve with the proximal portion of the headless screw.

In an embodiment, the outer sleeve includes a proximal portion and a distal portion connected via a friction interface, the distal portion being rotatable about a longitudinal axis thereof, such that, the distal portion correspondingly rotates along with the driving member relative to the proximal portion of the outer sleeve.

In an embodiment, when the distal end abuts the near cortex of the bone, the friction interface provides a feedback indicating that the proximal portion of the headless screw is driving into the bone.

The present disclosure may be further understood with reference to the following description and the appended drawings, wherein like elements are referred to with the same reference numerals. The present embodiments relate to the treatment of a bone and, in particular, to the treatment of fractures of long bones such as the femur, tibia, humerus, etc. Once the bone is placed into corrective alignment, an intramedullary nail is inserted through a medullary canal of the bone and fixed relative thereto via fixation screws. In particular, headless screws, which include a threading along an entire length thereof, may be inserted through fixation openings extending laterally through the intramedullary nail so that the headless screws are flush to the bone.

In some cases, however, headless screws can be inserted too far into the bone, which may cause the screw to interfere with the intramedullary nail, lose purchase in the near cortex, and/or protrude too far from the far cortex. The exemplary embodiments describe a system including an insertion device for a headless screw, which provides a tactile feedback to a user when the screw is flush to the bone, preventing the screw from being inserted too far into the bone. It will be understood by those of skill in the art that the terms proximal and distal, as used herein refer to a direction toward (proximal) and away from (distal) a user of the system described herein. It will be further understood that, although the embodiments described herein are directed to an intramedullary nail system for long bones, the insertion device and headless screw of the present disclosure may also be utilized for other bone fixation systems in which a headless screw should be inserted flush to the bone.

As shown in <FIG>, a system <NUM> for treating a bone comprises an insertion device <NUM> for inserting a headless screw <NUM> flush to a bone <NUM>. The headless screw <NUM> extends longitudinally from a proximal end <NUM> to a distal end <NUM> and includes a threading <NUM> along an entire length thereof. The insertion device <NUM> may include a driving member <NUM> for driving the headless screw <NUM> into the bone <NUM>, a retaining member <NUM> for engaging and retaining the headless screw <NUM> as the headless screw <NUM> is being driven into the bone <NUM>, and an outer sleeve <NUM> for providing a tactile feedback to a user (e.g., a surgeon), when the proximal end <NUM> of the headless screw <NUM> is flush to the bone. Each of the driving member <NUM>, retaining member <NUM> and the outer sleeve <NUM> are coupled to a handle member <NUM> so that the driving member <NUM>, retaining member <NUM> and the outer sleeve <NUM> are movable relative to one another to insert the headless screw <NUM> into the bone, as will be described in further detail below.

As shown in <FIG>, the headless screw <NUM> extends along a longitudinal axis from the proximal end <NUM> to the distal end <NUM>. The threading <NUM> extends along an entire length of the headless screw <NUM> so that the headless screw <NUM> is insertable into the bone <NUM> such that the proximal end <NUM> is flush with a near cortex of the bone <NUM>. In some embodiments, a proximal portion <NUM> of the headless screw <NUM> may have a larger core diameter and/or a larger threaded diameter than a remaining portion <NUM> of the headless screw <NUM>. A larger core diameter and outer diameter along the proximal portion <NUM> will increase an insertion torque as the headless screw <NUM> is being screwed (e.g., rotated) into the bone providing further tactile feedback to the user that the proximal portion <NUM> of the headless screw <NUM> is engaging the bone <NUM>. It will be understood by those of skill in the art that the core diameter of the proximal portion <NUM> may be defined via an exterior surface of the proximal portion <NUM> along which threads do not extend and/or via radially inner ends of the threads extending along the proximal portion <NUM>.

The proximal end <NUM> of the headless screw <NUM> includes a driving recess <NUM>, which extends distally into the proximal end <NUM> of the headless screw <NUM> along the longitudinal axis of the headless screw <NUM>. As shown in <FIG>, the driving recess <NUM> is configured to receive a correspondingly sized and shaped engaging portion <NUM> of the driving member <NUM> of the insertion device <NUM>. The driving recess <NUM> is configured so that, when the engaging portion <NUM> of the driving member <NUM> is received therewithin and rotated about a longitudinal axis thereof, a torsional force is applied to the headless screw <NUM> to drive the headless screw <NUM> into the bone <NUM>.

In one embodiment, the driving recess <NUM> includes a substantially circular central portion and a plurality of notches formed along a surface of the substantially circular central portion so that the notches extend radially outward from a longitudinal axis of the headless screw <NUM>. It will be understood by those of skill in the art that the driving recess <NUM> may include any number of notches in any of a variety of configurations so long as the notches are sized and shaped to engage corresponding portions of the engaging portion <NUM> of the driving member <NUM>. It will also be understood by those of skill in the art, that the driving recess <NUM> may have any of a variety of configurations so long as the driving recess <NUM> is engageable with the driving member <NUM>.

For example, in another embodiment, the driving recess <NUM> may have a hexagonal cross-section. In another example, the driving recess <NUM> may be star shaped. It will be understood by those of skill in the art, however, that the driving recess <NUM> may have any of a variety of shapes so long as a torsional force may be applied to the headless screw <NUM> thereby.

The proximal end <NUM> of the headless screw <NUM> also includes a retaining recess <NUM> extending distally from the driving recess <NUM>. The retaining recess <NUM> has a smaller cross-sectional area than the driving recess <NUM> and is configured to receive a threaded retaining portion <NUM> at a distal end <NUM> of the retaining member <NUM>. In one embodiment, the retaining recess <NUM> may include a threading <NUM> along an interior surface <NUM> thereof for engaging a correspondingly threaded engaging portion <NUM> of the retaining member <NUM>. As will be described in further detail below, engagement between the retaining member <NUM> and the retaining recess <NUM> aids in retaining (e.g., holding) the headless screw <NUM> to the insertion device <NUM> while the headless screw <NUM> is being driven into the bone <NUM>.

As described above, the insertion device <NUM> includes the driving member <NUM>, the retaining member <NUM> and the outer sleeve <NUM>. As shown in <FIG>, the driving member <NUM> extends longitudinally from a proximal end <NUM> to the engaging portion <NUM> at a distal end <NUM> thereof, and includes a channel <NUM> extending longitudinally therethrough. The proximal end <NUM> is connected to the handle member <NUM> so that, when the handle member <NUM> is rotated about a longitudinal axis of the insertion device <NUM>, the driving member <NUM> is correspondingly rotated to drive a headless screw <NUM> engaged to the engaging portion <NUM> into the bone <NUM>, as will be described in further detail below. Although the driving member <NUM> is shown and describes as including the handle member <NUM> at the proximal end <NUM>, in another embodiment, the proximal end <NUM> may be configured so that the proximal end <NUM> may be coupled to one of the handle member <NUM> and a power driver so that the headless screw <NUM> may be manually driven or power driven into the bone, as desired.

As shown in <FIG>, the retaining member <NUM> extends longitudinally from a proximal end <NUM> to the distal end <NUM> and is sized and shaped to be received within the channel <NUM> of the driving member <NUM>. In one embodiment, as described above, the distal end <NUM> include the threaded retaining portion <NUM> configured to engage the corresponding threading <NUM> of the retaining recess <NUM> of the headless screw <NUM>. The proximal end <NUM> of the retaining element <NUM> may be attached to, for example, a knob <NUM> which, when the retaining member <NUM> is received within the channel <NUM>, extends proximally of a proximal end <NUM> of the handle member <NUM>.

The retaining element <NUM> is longitudinally movable relative to the driving member <NUM> between a non-retaining configuration and a retaining configuration. In the non-retaining configuration, the distal end <NUM> of the retaining member <NUM> is flush with or proximal of the distal end <NUM> of the driving member <NUM> so that the distal end <NUM> of the retaining member <NUM> does not extend distally past the distal end <NUM> of the driving member <NUM>. Thus, even when the driving member <NUM> is engaged with the driving recess <NUM> of the headless screw, the distal end <NUM> of the retaining member <NUM> does not engage the retaining recess <NUM> when in the non-retaining configuration. The retaining member <NUM>, however, may be moved distally relative to the driving member <NUM> toward the retaining configuration, in which the distal end <NUM> of the retaining member <NUM> extends distally past the distal end <NUM> of the driving member <NUM> to engage the retaining recess <NUM> of the headless screw <NUM>.

Where the distal end <NUM> includes the threaded retaining portion <NUM>, the retaining member <NUM> may be rotated in a first direction about a longitudinal axis thereof to engage the threaded engaging portion <NUM> with the correspondingly threading <NUM> of the retaining recess <NUM>. The retaining member <NUM> may be rotated via, for example, the knob <NUM>. To move the retaining member <NUM> from the retaining configuration to the non-retaining configuration, the retaining member <NUM> is rotated about the longitudinal axis thereof in a second direction, opposite the first direction, until the threaded retaining portion <NUM> is unthreaded from the retaining recess <NUM>.

As shown in <FIG>, the outer sleeve <NUM> extends longitudinally from a proximal end <NUM> to a distal end <NUM> and includes a channel <NUM> extending longitudinally therethrough. The outer sleeve <NUM> is slidably mounted over the driving member <NUM> so that the outer sleeve <NUM> is longitudinally movable relative to the driving member <NUM> between a first position and a second position. In the first position, the distal end <NUM> of the outer sleeve <NUM> extends distally beyond the distal end <NUM> of the driving element <NUM> so that the distal end <NUM> extends over and covers the proximal portion <NUM> of the headless screw <NUM>, when the driving recess <NUM> of the headless screw <NUM> is engaged with the engaging portion <NUM> of the driving member <NUM>. In the second position, the outer sleeve <NUM> is drawn proximally relative to the driving member <NUM> so that the distal end <NUM> is aligned with the proximal end <NUM> of the headless screw <NUM>. In particular, a distal face <NUM> of the distal end <NUM> is longitudinally aligned with a proximal face <NUM> of the proximal end <NUM> of the headless screw <NUM>.

The headless screw <NUM> is initially inserted into a living body with the outer sleeve <NUM> in the first position until it reaches a target area of the bone <NUM> into which the headless screw <NUM> is to be driven. The headless screw <NUM> is inserted into the body with the proximal portion <NUM> covered to protect surrounding tissue from the threading <NUM> extending along the proximal portion <NUM> which acts as cutting flutes during implantation of the headless screw <NUM>. Upon reaching the target area, the outer sleeve <NUM> is retracted to the second position and the headless screw <NUM> is driven into the bone <NUM> until the distal face <NUM> of the outer sleeve <NUM> abuts the near cortex of the bone <NUM>. A distance by which the outer sleeve <NUM> is retracted, from the first position to the second position, corresponds to a length of the proximal portion <NUM> of the headless screw <NUM>. Thus, when the headless screw <NUM> is driven into the bone <NUM> and the distal face <NUM> abuts the near cortex of the bone <NUM>, the abutment between the outer sleeve <NUM> and the bone <NUM> provides tactile feedback to the user indicating that the proximal end <NUM> is flush with the bone <NUM>.

The outer sleeve <NUM> of this embodiment is be movable between the first and second positions via a locking mechanism <NUM> including a locking tab <NUM> biased toward a locking configuration via a biasing element <NUM>, as shown in <FIG>, although those skilled in the art will understand that any mechanism which permits the desired relative movement may be employed. In the locking configuration, the locking tab <NUM> extends into the channel <NUM> of the outer sleeve <NUM> to engage one of a first groove <NUM> and a second groove <NUM> along an exterior surface of the driving member <NUM>. When the locking tab <NUM> is received within the first groove <NUM>, the outer sleeve <NUM> is in the first position relative to the driving member <NUM>. When the locking tab <NUM> is in the second groove <NUM>, which is positioned proximally of the first groove <NUM>, the outer sleeve <NUM> is in the second position relative to the driving member <NUM>.

The locking tab <NUM> may be moved between the first and second grooves <NUM>, <NUM> by, for example, a push button <NUM> which, when pressed, moves the locking tab <NUM> out of the channel <NUM> and out of engagement with one of the grooves <NUM>, <NUM> toward an unlocked configuration. Thus, when it is desired to move the outer sleeve <NUM> between the first and second positions, the user may simply press the push button <NUM> and slide the outer sleeve <NUM> longitudinally proximally or distally relative to the driving member <NUM>. When the locking tab <NUM> is adjacent the other of the first and second grooves <NUM>, <NUM>, the locking tab <NUM> will revert to its biased locking configuration snapping into engagement the other one of the first and second grooves <NUM>, <NUM>.

Although the locking mechanism <NUM> is shown positioned at the proximal end <NUM> of the outer sleeve <NUM>, it will be understood by those of skill in the art that the locking mechanism <NUM> may be positioned anywhere along a length of the outer sleeve <NUM> so long as the locking mechanism <NUM> is accessible to a user during the implantation procedure and so long as the locking tab <NUM> may be received within the first and second grooves <NUM>, <NUM> to move the outer sleeve <NUM> relative to the driving member <NUM> between the first and second positions.

It will also be understood by those of skill in the art that, if so desired, the user may press the button <NUM> to slide the outer sleeve <NUM> proximally relative to the driving member <NUM> to remove the outer sleeve <NUM> from the insertion device <NUM>. It may be desired to remove the outer sleeve <NUM> for cases in which it is desired to implant the headless screw <NUM> distally beyond the near cortex of the bone <NUM>. It will be understood by those of skill in the art that the outer sleeve <NUM> may also be removed to drive conventionally shaped bone screws including a head. The head of the conventional bone screw may include both a driving recess and a retaining recess, substantially similar to the driving recess <NUM> and the retaining recess <NUM> described above.

According to an exemplary method of the present disclosure, the insertion device <NUM> is coupled to the headless screw <NUM> by inserting the engaging portion <NUM> of the driving member <NUM> into the driving recess <NUM> at the proximal end <NUM> of the headless screw <NUM> and engaging the distal end <NUM> of the retaining member <NUM> with the retaining recess <NUM> of the headless screw <NUM>. In one embodiment, upon inserting the engaging portion <NUM> of the driving member <NUM> into the driving recess <NUM> of the headless screw <NUM>, the threaded portion <NUM> of the retaining member <NUM> is engaged with the retaining recess <NUM> by rotating the retaining member about the longitudinal axis thereof in the first direction and distally therealong, relative to the driving member <NUM> and the headless screw <NUM>, so that the threaded retaining portion <NUM> threadedly engages the threading <NUM> of the retaining recess <NUM>.

The headless screw <NUM> is initially driven into the bone <NUM> with the outer sleeve <NUM> in the first position - i.e., with the distal end <NUM> extending over and covering the proximal portion <NUM> of the headless screw <NUM>. The headless screw <NUM> is driven into the bone <NUM> by rotating the driving member <NUM> about the longitudinal axis thereof until the distal end <NUM> of the outer sleeve <NUM> contacts the near cortex of the bone <NUM>, as shown in <FIG>, providing a first tactile feedback to the user, which indicates that the distal portion <NUM> of the headless screw <NUM> has been inserted into the bone <NUM> to a desired initial depth (e.g., until a distal end of the proximal portion of the screw <NUM> is adjacent to the near cortex of the bone).

The user then moves the outer sleeve <NUM> proximally relative to the driving member <NUM> to the second position, as shown in <FIG>, so that the distal face <NUM> of the outer sleeve <NUM> is aligned with the proximal face <NUM> of the headless screw <NUM>. As described above, the outer sleeve <NUM> may then be locked in the second position relative to the driving member <NUM> via the lock mechanism <NUM>. In one embodiment, the user may know that the distal portion <NUM> of the screw <NUM> has been fully inserted into the bone, after a predetermined number of full rotations of the headless screw <NUM> have been completed. For example, it may be known that two full turns of the headless screw <NUM> will result in a complete insertion of the distal portion <NUM> of the headless screw <NUM> into the bone <NUM> - i.e., the screw <NUM> has been inserted to the point at which the distal end of the proximal portion <NUM> of the screw <NUM> is adjacent to the near cortex of the bone <NUM>).

Once the outer sleeve <NUM> is fixed in the second position, the headless screw <NUM> is further driven into the bone <NUM> until the distal face <NUM> once again abuts the near cortex, as shown in <FIG>, indicating to the user, via a second tactile feedback that the headless screw <NUM> has been inserted into the bone <NUM> so that the proximal end <NUM> is flush with the near cortex. Where the predetermined number of turns for completing insertion of the headless screw <NUM> is known, the second tactile feedback may provide confirmation to the user that the proximal face <NUM> of the headless screw <NUM> is flush with the surface of the near cortex.

Once the headless screw <NUM> has been completely inserted into the bone <NUM>, as described above, the insertion device <NUM> is disengaged from the headless screw <NUM> and removed from the body, leaving the headless screw <NUM> implanted in the bone <NUM>, as desired. In particular, the retaining member <NUM> is disengaged from the headless screw <NUM> by rotating the retaining member <NUM> about the longitudinal axis thereof in the second direction, until the threaded retaining portion <NUM> has been completely unthreaded from the retaining recess <NUM>. The driving member <NUM> may then be disengaged from the driving recess <NUM> by simply withdrawing the insertion device <NUM> proximally from the headless screw <NUM>.

A system <NUM> for inserting a headless screw <NUM> into a bone <NUM> is shown in <FIG>. As described above, the system <NUM> facilitates insertion of the screw <NUM> to a desired position, for example, with a proximal end <NUM> of the headless screw <NUM> flush with a near cortex of the bone <NUM>. The system <NUM> may be substantially similar to the system <NUM> comprising an insertion device <NUM> including an outer sleeve <NUM> and a driving member <NUM> longitudinally slidable therewithin. Although not shown, it will be understood by those of skill in the art that the insertion device <NUM> may also include a retaining member substantially similar to the retaining member <NUM>, for retaining the headless screw <NUM> during insertion thereof into the bone. Similarly to the insertion device <NUM>, the outer sleeve <NUM> is longitudinally movable relative to the driving member <NUM> between a first initial position, as shown in <FIG>, and a second position, as shown in <FIG>, which indicates to a user that the headless screw <NUM> has been inserted into the bone <NUM> in the desired position - e.g., so that the proximal end <NUM> is flush with the bone <NUM>.

In this embodiment, however, in the first position, the outer sleeve <NUM> extends over and covers an entire length of the headless screw <NUM> so that a position of the outer sleeve <NUM> relative to the driving member <NUM> in the first position is based on a selected length of the headless screw <NUM>. Thus, prior to insertion of the headless screw <NUM> into the bone, the user may select a headless bone screw <NUM> having a desired length and adjust the outer sleeve <NUM> to a desired first position corresponding to the length of the selected headless bone screw <NUM>, as will be described in further detail below.

The headless bone screw <NUM> may be substantially similar to the bone screw <NUM> extending longitudinally from the proximal end <NUM> to the distal end <NUM> and including a threading extending along an entire length thereof. The headless screw <NUM> also includes a driving recess <NUM> extending into the proximal end <NUM>, the driving recess <NUM> being sized, shaped and configured to engage a correspondingly sized and shaped engaging portion <NUM> of the driving member <NUM>. The headless screw <NUM> may also include a retaining recess (not shown) substantially similar to the retaining recess of the headless screw <NUM>.

As described above, the insertion device <NUM> comprises the outer sleeve <NUM> and the driving member <NUM> slidably housed therewithin. The outer sleeve <NUM> may be substantially similar to the outer sleeve <NUM>, extending from a proximal end to a distal end <NUM> and including a channel <NUM> extending therethrough. The channel <NUM>, however, includes a shoulder <NUM> positioned along a distal portion thereof so that, as will be described in further detail below, the shoulder <NUM> acts as a stop to prevent further distal movement of the driving member <NUM> once the driving member <NUM> is in the second position relative to the outer sleeve <NUM>. A distal face <NUM> of the outer sleeve <NUM> may also include a plurality of teeth <NUM> protruding therefrom and configured to engage the bone <NUM> when the distal face <NUM> is pressed thereagainst. The teeth <NUM> hold the insertion device <NUM> in a target position along the bone <NUM> so that the headless screw <NUM> may be driven thereinto.

The driving member <NUM> may be substantially similar to the driving member <NUM> extending from a proximal end to a distal end <NUM> including the engaging portion <NUM> sized, shaped and configured to engage the driving recess <NUM> of the headless screw <NUM>. The driving member <NUM>, in this embodiment, however, further includes a plurality of grooves <NUM> extending longitudinally along a distal portion thereof. Each of the grooves <NUM> extends about a circumference of the driving member and is configured to receive a locking tab <NUM> of a locking mechanism <NUM>, as will be described in further detail below, for fixing the outer sleeve <NUM> and the driving member <NUM> in a desired first position relative to one another. Each groove <NUM> defines a selected length of the headless screw <NUM>. For example, a first groove 260a may represent a <NUM> screw, a second, immediately proximal groove 260b may represent a <NUM> and a third groove 260c immediately proximal the second groove 260b may represent a <NUM> screw, etc..

The locking mechanism <NUM> may, in this embodiment, include a sliding push button <NUM> slidable along a length of the outer sleeve <NUM> and relative to the driving member <NUM> so that a locking tab <NUM> thereof may engage a desired one of the grooves <NUM> of the driving member <NUM>. Similarly to the locking tab <NUM>, the locking tab <NUM> may be biased toward a locking configuration via a biasing element such as a spring. Thus, when the push button <NUM> is pressed, the biasing element is compressed to disengage the locking tab <NUM> toward an unlocked configuration so that by also sliding the push button <NUM> along a length of the outer sleeve <NUM>, the locking tab <NUM> may be moved to a desired position therealong, as shown in <FIG>, corresponding to a desired one of the grooves <NUM>. The push button <NUM> may then be released so that the locking tab <NUM> reverts to its biased configuration and engages a desired one of the grooves <NUM> corresponding to the selected length of the headless screw <NUM>. In this embodiment, the outer sleeve <NUM> includes markings <NUM> therealong to indicate positions corresponding to the desired lengths of the headless screw <NUM>.

Once a length of the headless screw <NUM> has been selected and the push button <NUM> has been adjusted to fix the outer sleeve <NUM> and the diving member <NUM> in the corresponding first position, the headless screw <NUM> may be inserted into the bone. The engaging portion <NUM> of the driving member <NUM> is inserted into the driving recess <NUM> so that, in the first position, the outer sleeve <NUM> extends over and covers an entire length of the headless screw <NUM>. In one embodiment, a distal tip of the headless screw <NUM> and the distal face <NUM> of the outer sleeve <NUM> are longitudinally aligned in the first position. The insertion device <NUM> is then pressed distally against a target portion of the bone <NUM> so that the teeth <NUM> along the distal face <NUM> of the outer sleeve <NUM> engages the bone <NUM>.

Once in this target position, the driving member <NUM> is rotated about a longitudinal axis thereof, relative to the outer sleeve <NUM>, and moved distally relative thereto so that the headless screw <NUM> is driven out of the outer sleeve <NUM> and into the bone <NUM>. The headless screw <NUM> may be driven into the bone <NUM> until a portion of the locking mechanism <NUM> abuts the shoulder <NUM>, indicating to the user that the driving member <NUM> and the outer sleeve <NUM> are in the second position relative to one another - i.e., the headless screw <NUM> is in the desired configuration within the bone <NUM>, in which the proximal face <NUM> of the headless screw <NUM> is flush with a near cortex of the bone.

As shown in <FIG>, a system <NUM> may be substantially similar to the systems <NUM>, <NUM>, as described above, comprising an insertion device <NUM> for inserting a headless screw <NUM> to a desired position within a bone <NUM> (e.g., with a proximal face <NUM> of the headless screw <NUM> substantially flush with a surface of a near cortex of the bone <NUM>). Similarly to the systems described above, the insertion device <NUM> includes an outer sleeve <NUM> within which a driving member <NUM> is longitudinally movable between a first initial position, as shown in <FIG>, and a second position, as shown in <FIG>, which indicates to a user that the headless screw <NUM> is in the desired position within the bone. Similarly to the outer sleeve <NUM>, when a distal face of the outer sleeve <NUM> abuts the near cortex of the bone <NUM>, the abutment between the outer sleeve <NUM> and the bone <NUM> provides tactile feedback to the user indicating that the headless screw <NUM> is inserted in the desired position within the bone <NUM>. In addition to the tactile feedback indicating the desired position of the headless screw <NUM>, the insertion device <NUM> provides an audible feedback as well, as will be described in further detail below.

The headless screw <NUM> is substantially similar to the headless screw <NUM>, as described above with respect to the system <NUM>. The outer sleeve <NUM>, as shown in <FIG>, is also substantially similarly to the outer sleeve <NUM>, the outer sleeve <NUM> extending from a proximal end <NUM> to a distal end <NUM> and includes a channel <NUM> extending therethrough. The outer sleeve <NUM> also includes a locking mechanism <NUM> at the proximal end <NUM>, including a locking tab <NUM> biased toward a locked configuration via a biasing element <NUM>. As shown in <FIG>, the driving member <NUM> is substantially similar to the driving member <NUM> and is configured to extend longitudinally through the channel <NUM> of the outer sleeve <NUM> and is longitudinally and rotationally movable relative thereto to drive the headless screw <NUM> into the bone <NUM> via an engaging portion <NUM> at a distal end <NUM> thereof. In a further configuration, the driving member <NUM> may have a channel extending therethough configured to accommodate a retaining member (not shown), the retaining member being substantially similar to the retaining member <NUM> shown in <FIG>.

Similarly to the insertion device <NUM>, the locking tab <NUM> of the locking mechanism <NUM> engages a first groove <NUM> of the driving member <NUM> in the first position and a second groove <NUM> of the driving member <NUM> in the second position. In this embodiment, however, the insertion device <NUM> is moved from the first position (<FIG>) toward the second position (<FIG>) as the headless screw <NUM> is driven into the bone toward the desired configuration. In particular, the locking tab <NUM> is moved from the first groove <NUM> toward the second groove <NUM> as the headless screw <NUM> is driven into the desired position within the bone.

In this embodiment, a ramped surface <NUM> extends between the first and second grooves <NUM>, <NUM>. The ramped surface <NUM> increases in diameter from a distal end <NUM> connected to the first groove <NUM> to a proximal end <NUM> proximate the second groove <NUM>. The distal end <NUM> has substantially the same diameter as the first groove <NUM> while the proximal end <NUM> has a larger diameter than the second groove <NUM>. Thus, as the driving member <NUM> is moved distally relative to the outer sleeve <NUM> to drive the headless screw <NUM> into the bone, the locking tab <NUM> slides from the first groove <NUM> along the ramped surface <NUM>, a biasing element of the locking mechanism <NUM> compressing as the locking tab <NUM> slides along the ramped surface <NUM> until the locking tab <NUM> is moved proximally past the proximal end <NUM> of the ramped surface <NUM> to be received within the second groove <NUM>.

As the locking tab <NUM> moves proximally past the proximal end <NUM> of the ramped surface <NUM>, the locking tab <NUM> reverts to its biased configuration so that the locking tab "clicks" into the second groove <NUM>, providing an audible feedback to the user. The audible feedback indicates to the use that the headless screw <NUM> has been fully inserted into the bone in the desired configuration so that the proximal face <NUM> of the headless screw <NUM> is substantially flush with a surface of the bone <NUM>.

As shown in <FIG>, a system <NUM> according to another exemplary embodiment may be substantially similar to the systems <NUM>-<NUM> described above, comprising an insertion device <NUM> for driving a headless screw <NUM> into a desired position within a bone. The insertion device <NUM> includes a driving member <NUM> extending through an outer sleeve <NUM>. Rather than including a separate retaining member, however, the outer sleeve <NUM>, in this embodiment, includes a threading <NUM> along a distal end of a channel <NUM> extending therethrough for engaging threading <NUM> along a proximal portion <NUM> of the headless screw <NUM> to retain the screw <NUM> while the screw <NUM> is being driven into the bone. In addition, the outer sleeve <NUM> includes a depth indicator <NUM> for indicating a depth of insertion of the proximal portion of the <NUM> of the headless screw <NUM> so that the user may drive the headless screw <NUM> to the desired position within the bone - e.g., so that a proximal face <NUM> of the screw <NUM> is flush to the bone.

Similarly to the outer sleeves <NUM> - <NUM>, the outer sleeve <NUM> extends from a proximal end <NUM> to a distal end <NUM> and includes the channel <NUM> extending therethrough. The outer sleeve <NUM>, however, further includes a proximal portion <NUM> and a distal portion <NUM>, which have a friction interface <NUM> such as, for example, a ratchet mechanism. The channel <NUM> extends through both the proximal and distal portions <NUM>, <NUM>. As described above, the channel <NUM> includes a distal threaded portion <NUM> for engaging and retaining the headless screw <NUM> during insertion of the screw <NUM> into the bone. Similarly to the outer sleeve <NUM>, a distal face <NUM> of the outer sleeve <NUM> includes teeth <NUM> or other gripping features configured to grip or engage the bone when the outer sleeve <NUM> is pressed distally thereagainst.

As shown in <FIG>, the proximal portion <NUM> includes the depth indicator <NUM> along a proximal surface <NUM> so that the depth indicator <NUM> is visible to a user of the insertion device <NUM>. The depth indicator <NUM> indicates to the user a depth of insertion of the proximal portion <NUM> of the headless screw <NUM>. It will be understood by those of skill in the art that a length of the proximal portion <NUM> of the headless screw <NUM> would be known to the user of the device <NUM>.

For example, in one embodiment, the proximal portion <NUM> of the headless screw <NUM> may have a length of approximately <NUM> so that when the depth indicator shows a corresponding depth of insertion, the user will know that the headless screw <NUM> has been fully countersunk. As will be described in further detail below, the proximal portion <NUM> also includes a mating feature <NUM>, which is sized and shaped to mate with a corresponding mating feature <NUM> of the driving member <NUM> so that, when the mating features <NUM>, <NUM> engage one another, the proximal portion <NUM> and the driving member <NUM> are keyed to one another so that the proximal portion <NUM> and the driving member <NUM> are non-rotatable relative to one another.

The driving member <NUM> is substantially similar to the driving members described above, including an engaging portion <NUM> at a distal end <NUM> thereof for engaging a driving recess <NUM> of the headless screw <NUM>. The driving member <NUM> extends through the channel <NUM> of the outer sleeve <NUM> and includes the mating feature <NUM> so that when the mating feature <NUM> engages the mating feature <NUM> of the proximal portion <NUM> of the outer sleeve <NUM>, the proximal portion <NUM> and the driving member <NUM> are keyed to one another. In one embodiment, the mating feature <NUM> of the proximal portion <NUM> may include a longitudinal groove extending along a surface of a portion of the channel extending therethrough while the corresponding mating feature <NUM> of the driving shaft <NUM> includes a correspondingly sized and shaped protrusion extending outward from the driving shaft <NUM> to be received within and slidable along the longitudinal groove of the mating feature <NUM>. It will be understood by those of skill in the art that the mating features <NUM>, <NUM> may have any of a variety of configurations so long as the mating features <NUM>, <NUM> key the driving member <NUM> and the proximal portion <NUM> relative to one another to prevent rotation of the driving member <NUM> relative to the proximal portion <NUM> while also permitting a distal movement of the driving member <NUM> relative thereto.

In user, the headless screw <NUM> is assembled with the insertion device <NUM> prior to insertion. In particular, the outer sleeve <NUM> is threaded over the proximal portion <NUM> of the headless screw <NUM> and the engaging portion <NUM> of the driving member <NUM> is inserted into the correspondingly sized and shaped driving recess <NUM> of the headless screw <NUM>. The headless screw <NUM> is then inserted into a body and positioned over a target area of the bone. The driving member <NUM> is then rotated to drive the headless screw <NUM> into the bone. Since the driving member <NUM> is keyed to the proximal portion <NUM> of the outer sleeve <NUM>, rotation of the driving member <NUM> also causes a rotation of the proximal portion <NUM>. In addition, since the proximal portion <NUM> and the distal portion <NUM> of the outer sleeve <NUM> have a frictional interface, the distal portion <NUM> is also correspondingly rotated along with the driving member <NUM> until the outer sleeve <NUM> is pressed distally against the surface of the bone.

Once the headless screw <NUM> has been driven far enough into the bone such that the outer sleeve <NUM> is pressed against the bone, the teeth <NUM> along the distal face <NUM> thereof the bone to prevent any further rotation of the distal portion <NUM> of the outer sleeve <NUM>. Thus, as the user continues to rotate the driving member <NUM> to drive the headless screw <NUM> further into the bone, the ratchet mechanism between the proximal and distal portions <NUM>, <NUM> is engaged, providing an audible feedback to the user as the proximal portion <NUM> rotates relative to the distal portion <NUM>. The audible feedback indicates that countersinking, driving of the proximal portion <NUM> of the headless screw <NUM> into the bone, has begun.

In one embodiment, when the distal face <NUM> of the outer sleeve <NUM> first contacts the bone, the depth indicator <NUM> may indicate an insertion of <NUM>. As the user continues to rotate the driving member <NUM>, however, the proximal portion <NUM> of the outer sleeve <NUM> also rotates relative to the distal portion <NUM> providing audible feedback while the depth indicator <NUM> shows how far the screw <NUM> has traveled. As the headless screw <NUM> is driven further into the bone, the headless screw <NUM> is also being unthreaded from the threaded distal portion <NUM> of the outer sleeve <NUM>. Once the depth indicator <NUM> indicates that the desired depth of insertion has been achieved - i.e., a desired length of the proximal portion <NUM> of the headless screw <NUM> has been inserted into the bone - the user may remove the insertion device <NUM> from the body, leaving the headless screw <NUM> implanted in the bone in the desired position.

Claim 1:
A bone screw insertion device (<NUM>; <NUM>), comprising:
an outer sleeve (<NUM>; <NUM>) extending from a proximal end (<NUM>; <NUM>) to a distal end (<NUM>; <NUM>) and including a channel (<NUM>; <NUM>) extending therethrough; and
a driving member (<NUM>; <NUM>) extending longitudinally through the channel (<NUM>; <NUM>) of the outer sleeve (<NUM>; <NUM>) from a proximal end (<NUM>; <NUM>) to a distal end (<NUM>; <NUM>) configured to engage a driving recess (<NUM>; <NUM>) of a bone screw (<NUM>; <NUM>), the outer sleeve (<NUM>; <NUM>) movable relative to the driving member (<NUM>; <NUM>) between a first position in which the distal end (<NUM>; <NUM>) of the outer sleeve (<NUM>; <NUM>) extends over and covers a proximal portion (<NUM>) of a bone screw (<NUM>; <NUM>) engaged with the driving member (<NUM>; <NUM>), to a second position in which the distal end (<NUM>; <NUM>) of the outer sleeve (<NUM>; <NUM>) is longitudinally aligned with a proximal end (<NUM>; <NUM>) of a bone screw (<NUM>; <NUM>) engaged with the driving member (<NUM>; <NUM>), characterized in that
the outer sleeve (<NUM>) includes gripping features (<NUM>) extending distally from the distal end (<NUM>) thereof, the gripping features (<NUM>) configured to engage the bone (<NUM>).