Powered bone screw device

A medical screwdriver for inserting a medical screw connected to a suture into a bone. The screwdriver includes a shaft adapted to hold a medical screw at its distal end, a motor adapted to rotate the shaft, and a suture-receiving channel leading from the distal end of the shaft to a point distanced from the distal end of the shaft by at least 50% of the length of the shaft.

BACKGROUND OF THE INVENTION

Attaching a suture to a bone is a task that is well known in the art of surgery. A common solution is to screw a threaded screw, to which the suture is attached, into the bone. However, screwdrivers used to perform this task may injure tissue surrounding the bone. In addition, during the insertion of the screw the suture dangles from the screw and may get stuck or otherwise interfere with the surgeon's operations.

BRIEF SUMMARY OF THE INVENTION

An aspect of some embodiments of the invention relates to a medical screwdriver which includes a long bore, in which a suture may reside while an anchor screw holding the suture is screwed into a bone. The bore is optionally at least a few centimeters long such that movements of the suture are sufficiently distanced from the bone and its surrounding flesh.

In some embodiments of the invention, the bore runs along the rotation axis of the screwdriver. Having the bore run along the rotation axis of the screwdriver minimizes the rotation of the suture, such that the suture does not substantially move and therefore does not hit flesh of the patient. In addition, when the suture does not substantially rotate there is substantially no danger of tearing and/or knotting due to rotation. In some embodiments of the invention, the bore is defined by a hollow shaft that turns the screw. Alternatively, the bore is defined by a hollow shaft, which runs parallel to the rotation axis of the screwdriver. For example, the hollow shaft carrying the suture may be connected to a sheath, which isolates a shaft of the screwdriver from a patient's flesh. In some embodiments of the invention, the bore has a ring shape which is defined between a shaft which turns the screw and a sheath which isolates the shaft which turns the screw from the flesh surrounding the bone.

An aspect of some embodiments of the invention relates to a stationary sheath for isolating a shaft of a medical screwdriver from surrounding tissue. The stationary sheath prevents the rotating shaft of the screwdriver from injuring tissue surrounding a bone into which a screw is inserted. Optionally, the sheath is rotationally locked to the screwdriver body.

Optionally, the stationary sheath comprises a collapsible shield cap, which surrounds a screw held by the screwdriver when the screw is not pressed against a bone.

There is therefore provided in accordance with an embodiment of the present invention, a medical screwdriver for inserting a medical screw connected to a suture into a bone, including a shaft adapted to hold a medical screw at its distal end, a motor adapted to rotate the shaft, and a suture-receiving channel leading from the distal end of the shaft to a point distanced from the distal end of the shaft by at least 50% of the length of the shaft.

Optionally, the suture-receiving channel leads to a point distanced from the distal end of the shaft by the length of the shaft. In some embodiments of the invention, the suture-receiving channel comprises a through bore defined in the shaft. Optionally, the hollow shaft is coupled to the motor through a gear pair and/or through a shaft housing which defines a bore therethrough. In some embodiments of the invention, the motor is held in a casing which defines a through channel, which channel leads from a first side of the casing close to a coupling to the hollow shaft to an opposite side of the casing.

Optionally, the screwdriver includes a switch having a first position in which a suture located in the channel is held tightly and a second position in which the suture is free to move.

Optionally, the screwdriver includes a stationary sheath that surrounds the shaft. Optionally, the stationary sheath is removable. In some embodiments of the invention, the stationary sheath comprises a key, which is adapted to fit in a respective notch in a casing of the motor. Optionally, the channel is defined between the stationary sheath and the shaft. Optionally, the stationary sheath comprises a distal collapsible shield, which is adapted to cover, in the absence of an axially applied force, at least a portion of a screw held by the shaft.

There is further provided in accordance with an embodiment of the present invention, a medical screwdriver for inserting a medical screw connected to a suture into a bone, comprising a shaft adapted to hold a medical screw at its distal end, a stationary sheath which surrounds the shaft and a motor adapted to rotate the shaft so as to push the screw into a bone. Optionally, the stationary sheath comprises a distal collapsible shield, which is adapted, in the absence of force, to cover at least a portion of a screw held by the shaft.

There is further provided in accordance with an embodiment of the present invention, a stationary sheath, comprising a sheath, a collapsible shield connected at a distal end of the sheath and a rotation stopper that prevents the sheath from rotating. Optionally, the rotation stopper comprises a key protruding from a proximal end of the sheath, which key is adapted to fit into a compatible grove of a screwdriver. In some embodiments of the invention, the sheath defines a slot and the rotation stopper comprises a rod, which is adapted to fit into the slot and to connect to a screwdriver. Optionally, the sheath is at least two centimeters long.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1is a schematic illustration of a medical screwdriver20, in accordance with an exemplary embodiment of the invention. Screwdriver20comprises a shaft22that grasps a screw24, which is to be inserted into a bone. Optionally, a distal tip28of shaft22comprises an elastic material that tightly grasps screw24. Alternatively or additionally, distal tip28comprises a magnet which grasps screw24. In some embodiments of the invention, distal tip28comprises a circumferential groove32that receives a head34of screw24. Alternatively or additionally, distal tip28comprises a perpendicular bar which fits into a groove in head34of screw24. A motor26is coupled to shaft22such that when the motor is actuated shaft22rotates screw24.

In some embodiments of the invention, shaft24defines an internal, central, through bore30. Bore30is adapted to receive a suture38which is attached to screw24. A body36of screwdriver20optionally also includes a channel40in which suture38resides during the operation of screwdriver20. Thus, suture38does not dangle in the proximity of the bone into which screw24is being inserted and/or near open flesh surrounding the bone, while screw24is revolving. Thus, suture38cannot cause damage to flesh of the patient to which the screw is inserted and/or entangle on any other object.

In some embodiments of the invention, suture38is attached to screw24before the screw is placed within distal tip28of shaft22. Optionally, in placing screw24in screwdriver24, a leading elastic stick (not shown) is attached to a distal end (i.e., far from screw24) of suture38, and the elastic stick is used to push suture38through bore30and channel40to a distal end42of channel40. Alternatively or additionally, the leading elastic stick is passed from distal end42of channel40to tip28where it is attached to suture38. The leading elastic stick is then pulled out of channel40with suture38. Further alternatively or additionally, suture38is inserted to bore30and/or channel40before it is attached to screw24.

After screw24is inserted into the bone, tip28releases head34of screw24and screwdriver20is optionally pulled away from screw24, allowing suture38to come out of bore30.

In some embodiments of the invention, a stationary sheath90surrounds shaft22, such that while shaft22rotates it does not injure surrounding flesh. Stationary sheath90is optionally anchored to body36as described hereinbelow with reference toFIG. 3.

FIG. 2Ais a schematic cross section view of body36of screwdriver20, in accordance with an embodiment of the present invention. Reference is also made toFIG. 2Bwhich is a schematic exploded perspective view of the pieces of body36, in accordance with an embodiment of the present invention. Motor26is optionally powered by a battery48(FIG. 2B), for example a lithium rechargeable battery, although substantially any other battery may be used. Alternatively or additionally, a plurality of batteries and/or a cord power supply are used.

In some embodiments of the invention, the transfer of rotational movements from motor26to shaft22includes a by-passing set-up which allows suture38to lay along a path between bore30and channel40while motor26operates. Optionally, the by-passing set-up comprises a pair of gears50which are situated on opposite sides of the longitudinal axis of shaft22. In some embodiments of the invention, the gears50are located on horizontal sides of the longitudinal axis of shaft22, allowing the suture to fall into channel40without guidance. Alternatively, the gears50are located on vertical sides or at any other location relative to the longitudinal axis. The use of a pair of gears provides a relatively stable transfer of force from motor26to shaft22.

Reference is also made toFIG. 2Cwhich is a schematic illustration of the connections of gears50, in accordance with an embodiment of the present invention. In an exemplary embodiment of the present invention, motor26rotates a motor shaft44which comprises a gear head46that interlocks into the pair of gears50. Shaft22fits into a shaft housing52having a proximal gear56which interlocks into the other end of the pair of gears50. Optionally, shaft housing52comprises a hexagonal receptacle58which tightly receives shaft22(FIG. 1). Alternatively, shaft52comprises any other shaped receptacle and/or other attachment device for receiving shaft22. Similarly to shaft22, shaft housing52comprises a bore60which has a common axis with bore30of shaft22(FIG. 1).

Alternatively to using gear pair50, motor shaft44is held (e.g., by body36and/or motor26) above, under or to the side of the longitudinal axis of shaft22, such that gear head46of motor shaft44interlocks into proximal gear56of shaft housing52. Thus, motor shaft44and shaft housing52or in a step configuration which allows suture38to pass out of shaft housing52into channel40.

In some embodiments of the invention, a casing of body36defines channel40along a side of the body. Alternatively, channel40is defined within the casing of body36or is defined by an external piece attached to body36.

In some embodiments of the invention, the pair of gears50is situated on a side of proximal gear56and gear head46such that they allow free passage of suture38between bore60and channel40. Optionally, a distributor62leads suture38between bore60and channel40without entangling in gears46and50. In some embodiments of the invention, a protective piece64prevents suture38from entangling within any of gears56and50.

In some embodiments of the invention, a stopper70which is connected to a user switch72can firmly grasp suture38so as to prevent the suture from moving, for example while inserting the screw to the bone.

Alternatively to inserting screw24to the bone with suture38already tied to the screw, suture38is tied to the screw after the screw is inserted to the bone, using bore30and channel40. Optionally, a suture leader (not shown) is used to push suture38through channel40and bore30to screw24. In some embodiments of the invention, screw24comprises resilient arms which receive the suture when it is pushed through bore30. Alternatively, screw24comprises any other device for attaching to a suture which tightly connects to sutures approaching the head of the screw in the direction of the long axis of the screw. Optionally, suture38is inserted with a loop tied at its end. Alternatively, suture38is inserted doubled over in a manner which pushes ahead a U shape. Further alternatively, a miniature ring, such as a key chain ring, is tied to the distal end of the suture when it is pushed through bore30. Alternatively or additionally, screw24comprises a loop into which suture38is threaded by the suture leader.

FIG. 3is a schematic illustration of sheath90, in accordance with an embodiment of the present invention. Sheath90optionally comprises a key92which fits into a respective notch94in body36of screwdriver20. Optionally, sheath90is a disposable detachable sheath which is easily replaced. Alternatively or additionally, sheath90is firmly and/or permanently anchored to screwdriver body36to prevent falling during use. In some embodiments of the invention, before each screw insertion, a separate sterile sheath90is placed around shaft22.

In some embodiments of the invention, sheath90comprises, at a distal end thereof, a collapsible shield96which has an open state in which it entirely covers screw24and a closed state in which it collapses onto a line98about at the location of head34of the screw. When screw24is pressed against a bone, the distal edges of collapsible shield96are pushed back while screw24enters the bone. When, however, screwdriver20is pulled away from the bone, collapsible shield96expands to cover screw24and prevent inadvertent damage to patient tissue. Optionally, the collapsible shield comprises a tube in which a plurality, e.g., between four and sixteen, of axial slots are cut.

In some embodiments of the invention, sheath90comprises a durable plastic, such as polyurethane, polypropylene and/or any other rigid biocompatible plastic. Alternatively or additionally, sheath90comprises any other suitable material. Optionally, collapsible shield96comprises the same material as sheath90and possibly is produced as an integral part of sheath90.

The inner wall of sheath90is optionally distanced from shaft22by a small distance which prevents sheath90from touching rotating shaft22. Optionally, the distance between the inner wall of sheath90and shaft22is smaller than a predetermined distance, e.g., 1 mm, so that the total diameter of shaft22with sheath90is not substantially increased by using sheath90. In addition, sheath90is also relatively thin. In some embodiments of the invention, sheath90covers the entire length of shaft22. Optionally, shaft22and sheath90are over 2, 4 or even 6 centimeters long so that screwdriver body36is not brought too close to the patient's bone.

In some embodiments of the invention, shaft22does not define a bore30, but rather suture38is confined between shaft22and sheath90. Alternatively or additionally, shaft22defines a partial bore within a distal portion thereof. Suture38passes through the distal portion and emerges therefrom to be confined between sheath90and shaft22. Optionally, sheath90comprises, at its distal end, a hole or slot through which suture38exits the area between sheath90and shaft22. The distal bore of shaft22optionally runs over a short distance (e.g., 0.5 cm), half the length of shaft22or most of the length of shaft22.

FIG. 4is a schematic bottom view of a medical screwdriver100and a compatible suture cartridge110, in accordance with an embodiment of the present invention. Screwdriver100comprises, along its bottom side, a slot102, suitable for receiving a suture38. Optionally, slot102is designed to tightly receive a suture holder104which prevents suture38from falling out through the long side of slot102. In some embodiments of the invention, a suture holder104and suture38are packaged together in suture cartridge110, optionally with screw24. In some embodiments of the invention, suture holder104prevents suture38from moving longitudinally within slot102. The distance along suture38between screw24and the beginning of suture holder104is optionally slightly larger than a shaft120of screwdriver100, so as to allow for a certain amount of pull of suture38toward screw24due to rotation of shaft120. Alternatively, suture holder104allows free longitudinal movement of suture38within slot102. Optionally, suture38is connected, on an opposite end from screw24to an anchor116which prevents suture38from passing entirely through slot102. The location of anchor116along suture38is optionally chosen in a manner which prevents suture38from dangling too freely near the patient. Alternatively or additionally, the location of anchor116is chosen so as to allow sufficient leeway of suture38due to the revolving of shaft120.

Before each screw insertion procedure, suture holder104of a cartridge110is pushed into slot102. Before or after insertion of suture holder104into slot102, screw24is placed at a tip of a shaft120of screwdriver100. After the screw is inserted to the bone, suture holder104is removed from slot102, thus freeing suture38from screwdriver100.

In some embodiments of the invention, after putting screw24and suture holder104in place, a sheath, such as sheath90(FIG. 3) is put in place surrounding shaft120. Thus, suture38is captured within sheath90and cannot dangle freely.

Alternatively, cartridge110includes a sheath (not shown) which is connected (optionally as an integral part) to suture holder104. Suture38is possibly located within the sheath in cartridge110. In some embodiments of the invention, the sheath is brought to surround shaft120from its distal tip122and then suture104is pressed into slot102. Alternatively or additionally, the sheath has a slot which allows shaft120to pass through when suture104is inserted to slot102. Optionally, the sheath comprises an elastic material in which a slot opens only when force is applied. When the sheath is pressed against shaft120the slot opens and lets the sheath surround the slot, but immediately closes again to surround shaft120from all directions.

In some embodiments of the invention, shaft120comprises a slot in which suture38lays while the shaft revolves. Optionally, an additional suture holder is used to keep suture38in the slot of shaft120. Possibly, a predetermined length of suture38is left free between the slot of shaft120and slot102, to prevent tearing of the suture when shaft120turns.

It will be appreciated that the above described methods may be varied in many ways, including, performing a plurality of steps concurrently, changing the order of steps and changing the exact implementation used. It should also be appreciated that the above described description of methods and apparatus are to be interpreted as including apparatus for carrying out the methods and methods of using the apparatus.

The present invention has been described using non-limiting detailed descriptions of embodiments thereof that are provided by way of example and are not intended to limit the scope of the invention. It should be understood that features and/or steps described with respect to one embodiment may be used with other embodiments and that not all embodiments of the invention have all of the features and/or steps shown in a particular figure or described with respect to one of the embodiments. Variations of embodiments described will occur to persons of the art.

It is noted that some of the above described embodiments may describe the best mode contemplated by the inventors and therefore may include structure, acts or details of structures and acts that may not be essential to the invention and which are described as examples. Structure and acts described herein are replaceable by equivalents which perform the same function, even if the structure or acts are different, as known in the art. Therefore, the scope of the invention is limited only by the elements and limitations as used in the claims. When used in the following claims, the terms “comprise,” “include,” “have” and their conjugates mean “including but not limited to.”