WO2008073949A1

WO2008073949A1 - Cable cutter

Info

Publication number: WO2008073949A1
Application number: PCT/US2007/087138
Authority: WO
Inventors: Alberto A. Fernandez Dell'oca
Original assignee: Synthes GmbH; Synthes USA LLC
Current assignee: Synthes GmbH; Synthes USA LLC
Priority date: 2006-12-12
Filing date: 2007-12-12
Publication date: 2008-06-19
Anticipated expiration: 2009-06-12

Abstract

A device for cutting cable within a living body, the device comprises a first sleeve defining a first lumen and extending to a first distal opening sized to receive a cable and a second sleeve received within the first lumen, the second sleeve defining a second lumen extending therethrough to a second distal opening sized to receive a cable, the second distal opening being positioned so that, in a first configuration, the first and second distal openings align to create a path from an exterior of the first sleeve to the second lumen, the first and second sleeves being moveable relative to one another to a second configuration in which the first and second distal openings are moved out of alignment with one another to cut a cable received therethrough.

Description

CABLE CUTTER

FIELD OF THE INVENTION

[0001J The present invention relates to orthopedics, and more particularly to a device for minimally invasively cutting excess surgical cable remaining after cable has been secured around a reduced fracture.

BACKGROUND

[0002] Bone cerclage using cable and crimps is a well-known technique. Since the development of the wire passer disclosed by A. Fernandez Dell' Oca in US Patent Application Publication No. 2007/0043377, the insertion and the loop of the cable around the fractured bone can be achieved via a minimal incision, reducing tissue injury. Thereafter, a long-nosed crimp pliers for deforming such a deeply located crimp via a minimal incision was disclosed by A. Fernandez Dell' Oca, in U.S. Provisional Patent Application No. 60/793623.

[00031 Cable cutter are tools specially designed to cut the excess cable remaining after the cable has been looped around and secured to a fractured bone. Existing cable cutters have the disadvantage of requiring significant spreading of the incision and intervening muscle tissue increasing trauma and requiring increased space in which to operate. An example of such a device is disclosed by Whiteside et al in US Patent No. 5,772,666.

SUMMARY OF THE INVENTION

[0004] It is an object of the present invention to provide a device that enables to cut the surgical cable remaining after it has been looped and secured by a crimp around the reduced fracture, achieving said cut through a minimal incision, as required for minimally invasive osteosynthesis.

[0005] It is a further object of the present invention to provide a device with a mechanism that enables to obtain an easy and neat snap, leaving a grouped stump, preventing the spread of the thin wires constituting the surgical cable while the cut is performed.

[0006] In order to fulfill these and other objectives the present invention consists in two preferred embodiments and provide a cable cutter which works in a scissor-like way that comprises a pair of operating handles attached to a long cutting system that reaches the cable next to the bone through a minimal incision, said long cutting system has a concave cutting side or hole which pull together the thin wires constituting the cable while performing the cut, thus achieving a neat and easy cut and preventing the spread of said thin wires in the cable stump.

[0007] The present invention is directed to a device for cutting cable within a living body, the device comprising a first sleeve defining a first lumen and extending to a first distal opening sized to receive a cable in combination with a second sleeve received within the first lumen, the second sleeve defining a second lumen extending therethrough to a second distal opening sized to receive a cable, the second distal opening being positioned so that, in a first configuration, the first and second distal openings align to create a path from an exterior of the first sleeve to the second lumen, the first and second sleeves being moveable relative to one another to a second configuration in which the first and second distal openings are moved out of alignment with one another to cut a cable received therethrough.

[0008] The invention and developments of the invention are described in greater detail below using partially schematic illustrations.

BRIEF DESCRIPTION QF THE DRAWINGS

[0009] Fig. 1 shows a perspective view of a cable cutter according to a first embodiment of the invention;

Fig. 2 shows a side view of the cable cutter of Fig. 1 ;

Fig. 3 shows a perspective view of components of the cable cutter of Fig. 1 ; Fig. 4 shows a perspective view of the cable cutter of Fig. 1 ;

Fig. 5 shows a side view of the cable cutter of Fig. 1 with a surgical cable passing therethrough and with a knob thereof unscrewed;

Fig. 6 shows a side view of the cable cutter of Fig. 5, after the knob has been screwed in pushing the inner sleeve thereof toward an outer sleeve;

Fig. 7 shows a perspective view of the cable cutter of Fig. 5 with the surgical cable passing through holes of cutting sleeves thereof;

Fig. 8 shows a perspective view of the cable cutter of Fig. 7 after handles thereof have been pushed together and the surgical cable has been cut;

Fig. 9 shows a side view of a cable cutter according to a second embodiment of the invention;

Fig. 10 shows a perspective view of the cable cutter of Fig. 9 passing through a minimal skin incision in an open position;

Fig. 1 1 shows a perspective view of the cable cutter of Fig. 9 passing through a minimal skin incision in a closed position;

Fig. 12 shows a side view of the cable cutter of Fig. 9 in position adjacent to a crimp;

Fig. 13 shows a side view of the cable cutter of Fig. 12 after pulling up from the surgical cable;

Fig. 14 shows a side view of the cable cutter of Fig. 12 after the surgical cable has been cut next to the crimp; and

Fig. 15 shows a side view of the cable cutter of Fig. 14, after the cable has retraceted into the crimp.

DETAILED DESCRIPTION

[0010] The present invention, which may be further understood with reference to the following description and appended drawings, wherein like elements are referred to with the same reference numerals. The present invention relates to the treatment of bone fractures and, in particular, relates to internal fixation devices for treating fractures. Exemplary embodiments of the present invention provide a minimally invasive means for cutting surgical cable or wire after it has been reduced around a fractured bone.

[0011] Figs. 1-8 show a first exemplary embodiment of a device of the present invention. In this embodiment, the device comprises a pair of handles 4a, 4b, rotatably coupled to one another with each handle 4a, 4b being connected to a corresponding sleeve. The handle 4a may, for example, be connected to an outer sleeve 5, while the handle 4b is connected to an inner sleeve 6 housed within the outer sleeve 5. The device further comprises a knob 10 attached to a swivel 9.

[0012] The outer sleeve 5 is substantially tubular and extends from a proximal end 18 to a distal end 20. The proximal end 18 may be open and is connected to the handle 4a while the distal end 20 is closed by a distal surface 20a except for a hole 7, which is preferably sized to accommodate a surgical cable 2. The inner sleeve 6 is also substantially tubular and extends from a proximal end 22 to a distal end 24. The proximal end 22 is open and connected to the handle 4b. The distal end 24 is closed by a distal surface 24a except for a hole 8, which may be substantially the same size as the hole 7 to accommodate the diameter of the surgical cable 2. When the handles 4a, 4b are in an open position, the holes 7, 8 are aligned with one another. Diameters of the outer and inner sleeves 5, 6 are preferably selected such that the outer and inner sleeves 5, 6 may pass through a minimal skin incision 3 and a length of the outer and inner sleeves 5, 6 is selected such that the distal ends 20, 24 extend far enough from the handles 4a, 4b to reach a target bone 1 when passed through the skin incision 3. In a preferred embodiment, the diameter of the sleeves 5, 6 may range from 6mm to 10mm while the length of the sleeves 5, 6may range from 150mm to 200 mm. As the inner sleeve 6 is housed within the outer sleeve 5, the diameter of the inner sleeve 6 is preferably less than the inner diameter of the outer sleeve 5 by an amount selected to permit a desired degree of relative movement of the inner sleeve 6 within the outer sleeve 5 as will be described in more detail below.

[0013] The handles 4a, 4b are rotatably coupled to one another such that they move relative to one another about the sleeves 5, 6. That is, each handle 4a, 4b is connected to a respective one of the sleeves 5, 6 such that longitudinal axes of the sleeves 5, 6 are substantially perpendicular to a direction of the rotational movement of the handles 4a, 4b. Thus, when the handles 4a, 4b are drawn together, the outer sleeve 5 and the inner sleeve 6 move relative to one another about their longitudinal axes. It should be noted that, although the outer sleeve 5 is described as connected to the handle 4a and the inner sleeve 6 is described as connected to the handle 4b, thos skilled in the art will understand that the sleeves 5, 6 may be connected to either of the handles 4a, 4b so long as one sleeve is connected to one handle and the other is connected to the other handle.

[0014] The device of the present invention may further include a knob 10 attached to a swivel 9 via a screw mechanism 26. The swivel 9 is attached the handle 4b such that it rotates about a pivot 16, as shown in Fig. 3. The swivel 9 may be rotated about the pivot 16 to move the knob 10 out of a position over the proximal ends 18, 22 of the sleeves 5, 6, respectively, as shown in Figs. 3 and 4 so that the inner sleeve 6 may be inserted into or removed from the outer sleeve 5 and then rotated back into position over the proximal ends 18, 22 of the sleeves 5, 6, respectively. The knob 10 also includes a lumen 28 aligned with the open proximal ends 1 8, 22 of sleeves 5, 6 so that they are in communication. When the knob 10 is turned, the screw 26 screws into the swivel 9 so that an end of the screw 26 pushes down on the proximal end 22 of the inner sleeve 6 pushing the inner sleeve 6 further into the outer sleeve 5 until the distal end 24 of the inner sleeve 6 abuts the distal end 20 of the outer sleeve 5.

[0015] To reduce a fracture along a length of a bone 1, a flexible wire or surgical cable 2 is passed around a fractured bone 1 via a minimal skin incision 3 as would be understood by those skilled in the art. Once the cable 2 has been looped around the fractured bone 1, the fracture may be reduced by applying tension to the cable 2 and, once a desired tension has been obtained, a crimp may be used to secure the cable 2 around the bone 1 maintaining the desired tension. After the cable 2 has been secured, it is necessary to cut the excess cable 2 extending from the crimp. Figs. 1 and 5-8 shown an exemplary surgical technique for cutting this excess cable 2 via a minimal skin incision 3.

[0016] As shown in Fig. 1 , the extending portion of the cable 2 is inserted through the holes 7, 8 and passed through the sleeves 5, 6 until it passes out of the lumen 28. The device is then slid along the cable 2 through the incision 3 until the distal end 20 of the outer sleeve abuts the crimp or other securing member to which the cable 2 is secured around the fractured bone 1. As shown in Fig. 5, the cable 2 is inserted into the holes 7, 8 with the handles 4a. 4b in an open position in which the holes 7, 8 are aligned with one another. Thus, the extending portion of the cable 2 does not need to be bent during insertion Additionally, the knob 10 is positioned over the proximal ends 18, 22 of the sleeves 5, 6 by swiveling swivel 9 about the pivot 16 such that the lumen 28 is in communication with the open proximal ends 18, 22 of the sleeves 5, 6, respectively, so that the cable 2 may easily pass through the entire device.

[0017] Once the device is in the appropriate position, the knob 10 is turned to screw the screw 26 into the swivel 9 so that a distal end of the screw 26 pushes down on the proximal end 22 of the inner sleeve 6 moving the distal end 24 of the inner sleeve 6 further into the outer sleeve 5 until the distal end 24 of the sleeve 6 abuts the distal end 20 of the outer sleeve 5, as shown in Fig. 6 As the knob 10 is turned, the holes 7, 8 remain aligned, as shown in Fig. 7. After the distal ends 20, 24 have attained full contact through the turning of the knob 10. the handles 4a, 4b arc drawn closed, as shown in Fig. 8, rotating the sleeves 5, 6 relative to one another. As the handles 4a, 4b are moved to the closed position, the outer sleeve 5 rotates in direction opposite that of the inner sleeve 6. For example, if the outer sleeve 5 rotates clockwise, the inner sleeve 6 rotates counter-clockwise, and vice versa. Thus, the drawing the handles 4a, 4b closed, moves the holes 7, 8 away from one another. The clearance between the outer diameter of the inner sleeve 6 and the inner diameter of the outer sleeve 5 is at least equal to the diameter of the holes 7 and 8 or, if one of these boles is made smaller than the other, at least equal to the diameter of the smaller of the holes 7 and 8. This permits the inner sleeve 6 to move relative to the outer sleeve 5 so that the holes 7 and 8 no longer even partially overlap and edges of these holes 7, 8 or one of these holes 7,8 which are sharpened to act as blades cut the cable 2.

[0018] As the holes 7, 8 move away from one another, the cable 2 that passes through the holes 7, 8 snaps, leaving a neat and grouped cable stump 13. The close contact between the distal end 20 of outer sleeve 5 and the distal end 24 of inner sleeve 6 prevents the cable from merely bending when handles 4a, 4b are closed and the sleeves 5, 6 rotate relative to one another. Thus, the close contact between the distal ends 20, 24 causes the cable 2 to be rapidly cut with the rotation of the sleeves 5, 6 leaving a grouped stump 13 and preventing fraying of end the cut cable 2. Once the cable 2 has been cut, the device may be removed and the incision 3 sutured.

[0019] As shown in Figs. 9 - 15, a device according to a second exemplary embodiment of the present invention comprises a pair of operating handles 4a, 4b. A distal end of the handle 4a is coupled to a proximal end 30 of a first one of a pair of blades 15a while a distal end of the handle 4b is coupled to a proximal end 30 of the other of the blades 15b. Distal ends of the blades 1 5a, 15b form a pair of opposed jaws 1 1. The blades 15a, 15b are rotatably coupled to one another at a pivot 32 so that, when the handles 4a, 4b are moved away from one another, proximal ends of the blades 15a, 15b rotate in opposite directions so that the opposed jaws 1 1 open and move away from one another. When the handles 4a, 4b are moved toward one another, the jaws 1 1 are rotated about the pivot 32 toward one another to the closed position. The device according to this embodiment further comprises an optional locking mechanism 14 to prevent the handles 1 5a, 15b from being inadvertenlly moved relative to one another. The locking mechanism 14 according to this embodiment includes a bar 38 coupled to the handle 4b and a channel member 39 coupled to the handle 4a with a screw/locking nut 40 extending from the bar 38, through the channel member 39. When the locking nut is tightened relative movement between the handles 4a, 4b is prevented and, when the locking nut is loosened, the screw/locking nut 40 is free to slide within the channel of the channel member 39 and the handles 4a, 4b are permitted to move relative to one another. Those skilled in the art will understand that any known locking mechanism may be substituted for this locking mechanism 14 so long as it is capable of securely locking the handles 4a, 4b in a desired position and is easily loosened to permit movement of the handles 4a, 4b as desired.

[0020] As shown in Fig. 9, the opposed jaws 11 are formed at an angle to the blades 15a. 15b. which are bowed inward such that, in an open position, as shown in Fig. 10, substantial portions of the blades 15 a, 15b overlap one another. The opposed jaws 1 1 arc formed with a concave inner surface such that the opposed jaws 1 1 together form a space 34 in which the cable 2 may be accommodated. The pivot 32 is located proximally of the opposed jaws 11 such that when the handles 4a, 4b are drawn closed, as shown in Fig. 1 1, the blades 15a, 15b cross over one another bringing proximal ends of the opposed jaws 1 1 closer together such that the proximal ends 36 of the opposed jaws 1 1 also overlap, thereby eliminating the space 34. The blades 15a, 15b are designed to be overlapping and inwardly curved so that the device may be inserted into an existing minimal incision 3 without requiring significant spreading of the incision 3, thereby reducing muscle trauma and tissue damage. A width of the blades 15a, 15b may be such that the blades 15a, 15b may be inserted into a minimal skin incision 3 without having to significantly spread the incision 3. A length of the blades 15a, 15b is preferably selected so that the opposed jaws 1 1 may reach a crimp 12, or other fastener maintaining the cable 2 secured around the bone 1. The angle of the opposed jaws 1 1 to the blades 15a, 15b is such that the jaws 1 1 may reach a point of the cable 2 as close to the crimp 12 as possible.

[0021] The device may be used to cut a remaining length of the cable 2 once the cable 2 has been secured around a fractured bone 1. The cable 2 may be secured around the fractured bone using a crimp 12. However, as would be understood by those of ordinary skill in the art, although the exemplary technique is described in reference to a crimp 12, the device and method of the present invention may be used to cut an excess portion of the cable 2 regardless of the fashion in which it has been secured around the bone 1. As shown in Figs. 10 - 15, in an exemplary technique using the device of the present invention, the cable 2 is inserted into the space 34 and the opposed jaws 1 1 of the device are slid along the cable to through a minimal skin incision 3 to the crimp 12 or other fastener. As the device is being slid along the cable 2, the device is locked in the open position, as shown in Fig. 10. In the open position, the blades 15a, 15b of the device overlap to close off the space 34 and maintain the cable 2 therewithin. In this position, the handles 4a, 4b may not be moved relative to one another preventing the cable 2 from being cut or released from the space 34 before the device is in a desired position adjacent to the crimp 12 with a bottom surface 42 of the opposed jaws 11 abutting a surface of the crimp 12, as shown in Fig. 12. When the bottom surface 42 abuts the surface of the crimp 12, the dc\ ice is pushed along the surface of the crimp 12 until the cable 2 that is held between the opposed jaws 1 1 becomes substantially perpendicular to the surface of the opposed jaws 1 1 , as shown in Fig. 13. Having the cable 2 substantially perpendicular to the opposed jaws 1 1 allows the cable 2 to be cut as close to the crimp 12 as possible.

[0022] After it is determined that the opposed jaws 1 1 of the device are in the appropriate position to cut the cable 2, 1he locking mechanism 14 is unlocked by loosening the bolt 40 and drawing the handles 4a, 4b closed. By drawing the handles 4a, 4b closed, the bar 38 and the channel member 39 of the locking mechanism 14 slide relative to one another such that the bar 38 and the channel member 39 overlap and the blades 15a, 15b move from an overlapped configuration to a crossed configuration, as shown in Fig. 1 1. As the blades 15a, 15b move to the crossed configuration, the blades rotate about the pivot 32 such that the proximal end 36 of the opposed jaws 11 move closer to one another, eventually crossing over one another and eliminating the space 34 between the opposed jaws 1 1 cutting the cable 2 leaving a neat and grouped cable stump 13, as shown in Fig. 14. Once the cable 2 has been completely cut through, the cable 2 is released from between the opposed jaws 1 1 such that the cable stump 13 falls back into place and the stump 13 is substantially hidden by the crimp 12, as shown in Fig. 15.

[0023] It will be understood by those skilled in the art that various modifications and variations can be made in the structure and methodology of the present invention, without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided that they come within the scope of the appended claims and their equivalents.

Claims

What is claimed is:

1. A device for cutting cable within a living body, the device comprising:

a first sleeve defining a first lumen and extending to a first distal opening sized to receive a cable; and

a second sleeve received within the first lumen, the second sleeve defining a second lumen extending therethrough to a second distal opening sized to receive a cable, the second distal opening being positioned so that, in a first configuration, the first and second distal openings align to create a path from an exterior of the first sleeve to the second lumen, the first and second sleeves being moveable relative to one another to a second configuration in which the first and second distal openings are moved out of alignment with one another to cut a cable received therethrough.

2. The device of claim 1, wherein a clearance between an outer diameter of the second sleeve and an inner diameter of the first sleeve is at least as great as a diameter of one of the first and second distal openings so that, in the second configuration, no portion of the first distal opening overlaps the second distal opening.

3. The device of claim 1, wherein an edge of one of the first and second distal openings is formed as a blade.

4. The device of claim 1 , further comprising a first handle coupled to the first sleeve and a second handle coupled to the second sleeve, moving the first and second handles relative to one another rotating the first and second sleeves between the first and second configurations.

5. The device of claim 2, wherein diameters of the first and second distal openings are substantially equal to one another.

6. The device of claim 4, further comprising a knob attached to one of the first and second handles via a swivel pivotally attached to the handle, the knob swiveling between a first position on an axis of the first sleeve and a second position in which the knob is moved off of the axis of the first sleeve opening a proximal end of the first sleeve,

7. The device of claim 6, further comprising a screw coupled to the knob so that when the knob is in the first position, turning the screw pushes a proximal end of the second sleeve distally into the first sleeve until a distal end of the second sleeve abuts a distal end of the first sleeve.

8. The device of claim 6, wherein, in the first position, a lumen of the knob is aligned with the first and second lumens.

9. The device of claim 1 , wherein a diameter of the first and second sleeve ranges from 6mm to 19 mm.

10. The device of claim 1 , wherein a length of the first and second sleeves ranges from 150 mm to 200 mm.

1 1. A method of cutting a cable within a living body, comprising:

inserting a cable through a first distal opening in a first sleeve and through a second distal opening in a second sleeve received within a first lumen of the first sleeve to a second lumen extending through the second sleeve; sliding the first and second sleeves over the cable through an incision to a desired position within a living body in which a target portion of the cable to be cut is located within the first and second distal openings;

moving the first and second sleeves relative to one another to a second configuration in which the first and second distal openings are out of alignment with one another to cut the cable.

12. The method of claim 9, wherein the cable is looped around a fractured bone and the target portion of the cable is immediately proximal to a securing element securing the cable around the bone.

13. The method of claim 10, wherein the securing element is a crimp.

14. The method of claim 10, further comprising rotating the first and second sleeves relative to one another to move the first and second holes into and out of alignment with one another.

15. The method of claim 1 1, wherein the first and second sleeves are coupled to first and second handles, respectively, moving the first and second handles away from one another moving the first and second distal openings into alignment with one another and moving the first and second handles toward one another bringing the first and seecond distal openings out of alignment with one another.

16. The method of claim 10, wherein a clearance between an outer diameter of the second sleeve and an inner diameter of the first sleeve is at least as great as a diameter of one of the first and second distal openings.

17. A device for cutting cable within a living body, the device comprising:

first and second handles pivotally coupled to one another, the first and second handles being coupled to first and second blades, respectively, the first and second blades forming a pair of opposed jaws, movement of the first and second handles relative to one another moving the jaws between a first position and a second position wherein, in the first position, a space is formed between the jaws with distal ends of the jaws overlapping to close the space wherein, in the second position, proximal portions of the jaws overlap to close the space so that moving the jaws from the first position to the second position cuts a cable received within the space.

18. The device of claim 15, wherein the opposed jaws are angled relative to the first and second blades.

19. The device of claim 15, further comprising a locking mechanism which, when engaged, prevents movement of the first and second handles relative to one another and, when disengaged, permits the handles to move relative to one another to move the jaws between the first and second positions.

20. The device of claim 17, wherein the locking mechansim comprises a first element attached to the first handle and a second element attached to the second handle, the first element and the second element being slidably coupled to one another via a locking element which, in a first configuration locks the first and second elements to one another and in a second configuration permits relative movement between the first and second elements.

21. The device of claim 18, wherein the locking element includes a screw rigidly coupled to the first element and a nut mounted on the screw, the screw being slidably received within a channel of the second element so that, when the nut is tightened the first and second elements are immovably fixed to one another and, when the nut is loosened, the screw slides within the channel to permit relative movement between the first and second elements.