Cannulated flexible drive shaft

This application claims the benefit of U.S. Provisional Patent Application No. 61/357,651, filed Jun. 23, 2010. The patent application identified above is incorporated herein by reference in its entirety to provide continuity of disclosure.

This invention relates to tools used for performing surgeries, such as arthroscopic or orthopedic procedures, more particularly, a cannulated flexible drive shaft having a plurality of interlocking sections, preferably locked together by multi-angled dovetails, along the shaft that allow a distal end to be flexible while withstanding the torque from being rotated clockwise or counterclockwise thereby preventing the dovetails from separating and failing.

The limitations on maneuverability imposed by arthroscopic surgery mean that conventional straight drive shafts are not well suited for such procedures. Therefore, various arthroscopic surgical procedures utilize flexible drive shafts to drill into bone, ream bone, punch holes into bone, push anchors or screws into bone, tap anchors or screws into bone, screw anchors or screws into bone and securing sutures to bone, tendons and so forth. Conventional flexible drive shafts have a helical coil located along the entire drive shaft or along a portion of the distal end of the drive shaft. The helical coil allows a user to pass the drive shaft through a bent guide. However, depending on the orientation of a helical design, the coils will tighten together when turned clockwise and separate or pull apart when turned counterclockwise or vice versa for drive shafts having a helical design with an opposite orientation. Therefore, currently a surgeon needs two flexible drive shafts. One that will transmit torque in a clockwise direction and one that will transmit torque in a counter-clockwise direction.

Therefore, a need exists for a cannulated flexible drive shaft that will transmit torque in a clockwise direction as well as a counterclockwise direction without the drive shaft being pulled apart.

The primary object of the present invention is to provide a flexible drive shaft that will transmit torque in a clockwise direction as well as a counterclockwise direction.

A further object of the present invention is to provide a flexible drive shaft that is strong enough to withstand the torque being placed on it while in use.

The present invention fulfills the above and other objects by providing a flexible cannulated drive shaft having a plurality of interlocking sections having an angled dovetail design cut into the drive shaft. Each interlocking section has a proximal end, a distal end and a dovetail design comprising substantially triangular-shaped pins and substantially triangular-shaped sockets that alternate around the circumference of the proximal end and/or distal end of each interlocking section. The pins of one interlocking section moveably engage the sockets of a second interlocking section and vice versa. The substantially triangular-shaped pins and substantially triangular-shaped sockets secure the interlocking sections together while allowing the drive shaft to be flexible. An additional benefit of the interlocking sections is that the distance between each section may be cut larger or smaller to achieve a more or less flexible drive shaft. Furthermore, the substantially triangular-shaped pins and substantially triangular-shaped sockets stay locked together whether the drive shaft is being rotated clockwise or counterclockwise. The drive shaft may be used as a manual tool, such as a screw driver, or attached to a rotational tool, such as a drill. A guide allows a user to control the placement and depth of the distal end of the drive shaft during operations.

The above and other objects, features and advantages of the present invention should become even more readily apparent to those skilled in the art upon a reading of the following detailed description in conjunction with the drawings wherein there is shown and described illustrative embodiments of the invention.

In the following detailed description, reference will be made to the attached drawings in which:

FIG. 1 is an isometric perspective view of a flexible cannulated drive shaft of the present invention;

FIG. 2 is a side view of dovetail sections from a flexible cannulated drive shaft of the present invention;

FIG. 3 is an exploded top plan view of a laid flat interlocking section dovetail design and a top view of a laid flat opposing interlocking section dovetail design of the present invention;

FIG. 4 a cross section of an interlocking section along line 4 - 4 of FIG. 3 ;

FIG. 5 a cross section of an interlocking section along line 5 - 5 of FIG. 3 ;

FIG. 6 a cross section of an interlocking section along line 6 - 6 of FIG. 3 ;

FIG. 7 a cross section of an interlocking section along line 7 - 7 of FIG. 3 ;

FIG. 8 a cross section of an interlocking section along line 8 - 8 of FIG. 3 ;

FIG. 9 a cross section of an interlocking section along line 9 - 9 of FIG. 3 ;

FIG. 10 is a side plan view of a screwdriver having a flexible cannulated drive shaft of the present invention therein;

FIG. 11 is a side plan view of an external guide of the present invention;

FIG. 12 is a side view of an internal guide of the present invention;

FIG. 13 is a side perspective view of a flexible cannulated drive shaft of the present invention comprising a dovetail design having substantially round-shaped pins and substantially round-shaped sockets; and

FIG. 14 is a protective sheath of the present invention.

For purposes of describing the preferred embodiment, the terminology used in reference to the numbered components in the drawings is as follows:

With reference to FIGS. 1 and 2 , a side perspective view of a flexible cannulated drive shaft 1 of the present invention and a side view of interlocking sections 6 of the present invention, respectively, are shown. The drive shaft 1 is preferably tubular and comprises an outer surface 2 , an inner surface 3 , a proximal end 4 and a distal end 5 . A plurality of interlocking sections 6 are located along the drive shaft 1 . As shown in FIG. 2 , each interlocking section 6 has a proximal end 4 , a distal end 5 and a dovetail design 9 comprising substantially triangular-shaped pins 7 and substantially triangular-shaped sockets 8 that alternate around the circumference of the proximal end 4 and/or distal end 5 of each interlocking section 6 . The preferred shape of the pins 7 and sockets 8 is substantially triangular shaped, however the pins 7 and sockets 8 may also be substantially round shaped.

The pins 7 of one interlocking section 6 moveably engage the sockets 8 of a second interlocking section 8 and vice versa. The substantially triangular-shaped pins 7 and substantially triangular-shaped sockets 8 secure the interlocking sections 6 together while allowing the drive shaft 1 to be flexible. The substantially triangular-shaped pins 7 and corresponding substantially triangular-shaped sockets 8 are cut at opposing angles (as illustrated further in FIGS. 4-10 ) to allow for increased flexibility and to further lock the sections 6 together and prevent the interlocking sections from separating. Furthermore, the substantially triangular-shaped pins 7 and substantially triangular-shaped sockets 8 stay locked together whether the drive shaft 1 is being rotated clockwise or counterclockwise.

Now referring to FIG. 3 , an exploded top view of a laid flat interlocking section 6 dovetail design 9 and a top view of a laid flat opposing interlocking section 6 dovetail design 9 of the present invention is shown. The flexible portion of the drive shaft 1 is made by cutting interlocking sections 6 into a tubular shaft 10 . Each cut 11 is made around the entire circumference of the tubular shaft 10 to create a dovetail design 9 comprising alternating substantially triangular-shaped pins 7 and substantially triangular-shaped sockets 8 . The substantially triangular-shaped pins 7 and corresponding substantially triangular-shaped sockets 8 are cut at opposing angles to allow for increased flexibility and to further lock the sections 6 together and prevent the interlocking sections from separating. Each triangular-shaped pin 7 has inward angled surfaces 21 and outward angled surfaces 22 that correspond to inward angled surfaces 21 and outward angled surfaces 22 of an opposing triangular-shaped socket 8 . The inward angled surfaces 21 or outward angled surfaces 22 may be located on inner portions 23 of triangular-shaped sockets 8 , side portions 24 of triangular-shaped pins 7 or outer portions 25 of triangular-shaped pins 7 .

Now referring to FIG. 4 , a cross section of an interlocking section along line 4 - 4 of FIG. 3 showing inward angled surfaces 21 located on inner portions 23 of triangular-shaped sockets 8 .

Now referring to FIG. 5 , a cross section of an interlocking section along line 5 - 5 of FIG. 3 showing outward angled surfaces 22 located on side portions 24 of a triangular-shaped pin 7 .

Now referring to FIG. 6 , a cross section of an interlocking section along line 6 - 6 of FIG. 3 showing inward angled surfaces 21 located on outer portions 25 of triangular-shaped pins 7 .

Now referring to FIG. 7 , a cross section of an interlocking section along line 7 - 7 of FIG. 3 showing outward angled surfaces 22 located on inner portions 23 of triangular-shaped sockets 8 .

Now referring to FIG. 8 , a cross section of an interlocking section along line 8 - 8 of FIG. 3 showing inward angled surfaces 21 located on side portions 24 of a triangular-shaped pin 7 .

Now referring to FIG. 9 , a cross section of an interlocking section along line 9 - 9 of FIG. 3 showing outward angled surfaces 22 located on outer portions 25 of triangular-shaped pins 7 .

Now referring to FIG. 10 , a side plan view of a screwdriver 13 having a flexible cannulated drive shaft 1 of the present invention therein is shown. The screwdriver 13 may be used for inserting a suture anchor 14 into a bone. The screwdriver 13 comprises a proximal end 4 and a distal end 5 . A handle 15 is located on the proximal end 4 of the screw driver 13 . A flexible cannulated drive shaft 1 extends outward from the distal end 5 of the handle 15 . A hollow portion 16 of the handle 15 accepts a proximal end 4 of an external guide 17 (as shown in FIG. 11 ) and works in conjunction with a stop 18 located on the guide 17 to control the distance that the drive shaft 1 is able to extend from a distal end 5 of the guide 17 . A head 19 located on the distal end 5 of the drive shaft 1 is used to engage and rotate the suture anchor 14 . A plurality of interlocking sections 6 are located along the drive shaft 1 near the distal end 5 of the screwdriver 13 . The handle 15 of the screwdriver 13 is preferably tubular to allow for a suture 20 attached to the suture anchor 14 to be passed through the handle 15 . Although the flexible cannulated drive shaft 1 shown here is attached to a handle 15 , it may be attached to any rotational tool, such as a drill.

Now referring to FIG. 11 , a side plan view of an external guide 17 of the present invention is shown. The external guide 17 is preferably a tubular shaft having a proximal end 4 and a distal end 5 . The external guide 17 may be bent and curved to control the positioning of the drive shaft 1 during operations. The distal end 8 of the external guide 17 is preferably pointed so that the pointed distal end can be inserted into a bone, thereby locking the external guide 17 in place on the bone. A stop 18 is located on the near the proximal end 4 of the external guide 17 . A hollow portion 16 of the handle 15 (as shown in FIG. 10 ) accepts the proximal end 4 of the external guide 17 and works in conjunction with the stop 18 located on the external guide 17 to control the depth that the drive shaft 1 is able to extend out of the distal end 5 of the external guide 17 . The stop 18 may be adjustable to allow a user to increase the distance between the proximal end 4 of the external guide 17 and the stop 18 .

Now referring to FIG. 12 , a side view of an internal guide 26 of the present invention is shown. The internal guide 26 is preferably a tubular shaft having a proximal end 4 and a distal end 5 . A handle 27 is preferably located on the proximal end 4 of the internal guide 26 . The internal guide 26 is preferably constructed from shape memory alloy or any other shape memory material that has an elastic effect, thereby allowing a user to forge a constant curve in the material that can be temporarily straitened when pressure is applied the curve. The internal guide 26 is used to control the positioning of the drive shaft 1 during operations. The curved section of the internal guide 26 may be temporarily straitened to be passed through the tubular handle 15 of the screwdriver 13 and through the cannulated drive shaft 1 . The curved section of the internal guide 26 will the return to its curved shape, thereby placing a desired curve in the flexible portion of the cannulated drive shaft 1 .

Now referring to FIG. 13 , a side perspective view of a flexible cannulated drive shaft 1 of the present invention comprising a dovetail design 9 having substantially round-shaped pins 7 and substantially round-shaped sockets 8

Finally referring to FIG. 14 , a protective sheath 28 of the present invention is shown. The protective sheath 28 is preferable made of a plastic or rubber material and is placed over the cannulated drive shaft 1 to cover the interlocking sections 6 . The protective sheath 28 prevents the gaps between the interlocking sections 6 from becoming filled with foreign matter.

It is to be understood that while a preferred embodiment of the invention is illustrated, it is not to be limited to the specific form or arrangement of parts herein described and shown. It will be apparent to those skilled in the art that various changes may be made without departing from the scope of the invention and the invention is not to be considered limited to what is shown and described in the specification and drawings.