WO2006014306A1

WO2006014306A1 - Wire tensioner

Info

Publication number: WO2006014306A1
Application number: PCT/US2005/023249
Authority: WO
Inventors: Christian E. Sampson
Original assignee: The Brigham And Women's Hospital, Inc.
Priority date: 2004-07-02
Filing date: 2005-06-29
Publication date: 2006-02-09

Abstract

A wire tensioner may include a head portion and a torque driver. The head portion may be sized and shaped to fixedly engage two free ends of a surgical wire that is placed around an anatomic structure. The torque driver may include a handle so coupled to the head portion as to transmit torque exerted on the handle to the head portion and thence to the surgical wire ends, thereby twisting the ends about each other. The torque driver may also include at least one of a torque meter to indicate to a user the torque exerted, and a torque limiter to limit the torque that is transmitted to the head.

Description

WIRE TENSIONER

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Application No. 60/585,329, filed July 2, 2004, which is hereby incorporated herein by this reference.

FIELD

[0002] The disclosed systems and methods relate generally to systems and methods for tensioning surgical wires. More specifically, the disclosed systems and methods relate to twisting wires to a controlled and reproducible tightness to promote wound closure and healing.

BACKGROUND

[0003] Surgical procedures that involve cutting bone and/or cartilage often require that the separated fragments be rejoined at the conclusion of the procedure. For example, after a sternotomy, the split halves of the bisected sternum are reapproximated and held together by a series of wire sutures. Each suture is slipped around the two halves, and the two free ends of the suture are twisted together to compress the halves against each other. See, for example, FIG. 1.

[0004] The wires, by applying and maintaining the compression, promote healing of the sternal incision and also prevent wound dehiscence. If the wires are too loose, the sternal halves are prone to separation ("dehiscence"), the wound healing process cannot occur efficiently, and the patient is vulnerable to infection through the wound. If, on the other hand, the wires are too tight, discomfort to the patient and trauma to the bone may result. [0005] The conventional technique of tightening wire sutures involves clamping the wire free ends in a needle driver and twisting the driver, thereby twisting the free ends about each other. There is no control over how much the wires are tightened; surgeons use trial and error, and, in the end, their individual judgment and experience to decide when the wires are tight enough. A surgeon's best guess, however, may turn out to be wrong. As a result, patients suffer increased risks of complications due to poor wound closure. SUMMARY

[0006] The present disclosure provides systems and methods for tightening wire sutures in a controllable and reproducible manner.

[0007] In one embodiment, a wire tensioner may include a head portion and a torque driver. The head portion may be sized and shaped to fixedly engage two free ends of a surgical wire that is placed around an anatomic structure. The torque driver may include a handle so coupled to the head portion as to transmit torque exerted on the handle or generated by the driver to the head portion and thence to the surgical wire ends, thereby twisting the ends about each other. The torque driver may also include at least one of a torque meter to indicate to a user the torque exerted, and a torque limiter to limit the torque that is transmitted to the head.

[0008] In another embodiment, a method of tensioning surgical wire may include placing a surgical wire around an anatomic structure so that the wire ends are free, engaging the wire free ends in a wire tensioner described above, and exerting torque on the handle of the tensioner, thereby twisting the wire ends about each other.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 depicts a sternotomy closed by a series of wire sutures.

[0010] FIG. 2 depicts an exemplary embodiment of a wire tensioner.

[0011] FIG. 3 depicts an exemplary embodiment of a head portion of a wire tensioner. [0012] FIGS. 4 and 5 depict an exemplary use of the embodiment of a wire tensioner as shown in FIGS. 2 and 3.

[0013] FIGS. 6-10 depict alternative exemplary embodiments of head portions of wire tensioners.

[0014] FIG. 11 depicts an exemplary embodiment of a wire tensioner having a torque meter.

DETAILED DESCRIPTION

[0015] The disclosed systems and methods facilitate wound closure by giving the user control over how much torque is delivered to wire sutures used in wound closure. Wire tensioners according to the present disclosure typically include at least two elements: a torque driver and a head portion. The head portion receives the free ends of a surgical wire and holds them in place while the torque driver exerts rotational force on the head portion, causing the wire ends to twist about one another. The torque driver may have a mechanism for limiting the amount of torque transmitted to the head portion, so that the user can twist the wire ends to a desired tension in a controlled and repeatable fashion without the inherent variability of existing methods. Alternatively, the torque driver may have a mechanism for reporting the torque exerted to the user. In some cases, the torque driver may include both the torque limiter and the torque meter. In these cases, the user can monitor the performance of the device and/or be able to provide a manual safety override if the torque limiter fails to cutout at the desired torque.

[0016] In addition to wound closure, the wire twisting system can be used for other procedures, such as securing fractures or orthopedic reconstructive procedures. The torque control systems and methods can also be used to control the insertion of surgical screws for affixing implants or managing fractures, where undertightening does not provide enough fixation for healing, and overtightening may cause bone resorption and consequent loosening of the fixed structure(s). Furthermore, the disclosed systems and methods can be used in nonsurgical settings where it is preferred that wire or screw tension be controlled.

[0017] 1. The Head portion

[0018] FIG. 2 depicts an exemplary embodiment of a surgical wire tensioner 10. The tensioner may include a torque driver 20 and a head portion 30 coupled to the driver. The driver may include a handle 21 by which a user may grasp the tensioner and apply torque.

In some embodiments, the torque driver can also generate torque by operation of a motor.

The driver may define a chamber to receive a power source, such as batteries.

Alternatively, the driver may include a cable and/or receptacle for connection to an external power source. A wide variety of motor-driven rotational tools, such as power screwdrivers, are known in the art and may be adapted for use with the present wire tensioner. In some embodiments, the driver may also include a calibration and/or scale setting 22 by which a user may calibrate the device to a torque standard or select a particular torque setting for the device.

[0019] The head portion 30 may include a shaft 31 and some mechanism for receiving the free ends of a wire. In FIG. 2, the mechanism is provided by a pair of bores 33 that communicate between front apertures 32 and side holes 34. FIG. 3. shows detail of this embodiment in a perspective view. Use of this mechanism will be described further with reference to FIGS. 4 and 5.

[0020] The head portion is coupled to the driver 20 so that torque exerted on or generated by the driver is transmitted to the head portion. In some embodiments, the head portion may be integrally formed with the driver. For example, shaft 31 may be a continuation of a shaft emerging from the driver. In other embodiments, the head portion may be an attachment that can be affixed to a shaft emerging from the driver, much as a screwdriver head can be attached to a power handle, or a drill bit fixed to a drill with a chuck. In some embodiments, the head portion may be disposable, so that (for example), a head portion may be used during a surgical procedure and then discarded, while the driver is retained for reuse. In some embodiments, the head portion may be sterilizable, such as by chemical treatment, irradiation, and/or autoclaving, so that it can be reused in a subsequent surgical procedure. In some embodiments, the entire device can be disposable, so that it is used for a single procedure and then discarded. [0021] FIG. 4 shows how a wire tensioner as shown in FIGS. 2 and 3 may be used. A wire 40 is placed around a structure — in the depicted embodiment, a sectioned bone 50 — so that it has two free ends 42. The free ends can be crossed over one another once, so that they face away from one another, and tugged to help reapproximate the bone sections. Alternatively, the bone can be reapproximated by manual manipulation or with other instruments. The free ends may be given one or two manual twists to hold the bone sections together. Each free end may then be inserted in an aperture 32, through the bore 33 and out side hole 34. Each free end is then crooked, such as by bending at a sharp angle or winding around the shaft, to fix the wire ends temporarily with respect to the shaft. This helps to drag the wire ends along with the shaft when the shaft rotates and to prevent the wire ends from backing out of the bores.

[0022] Then, as shown in FIG. 5, torque is applied to the shaft to cause rotation R. The wire 40, held in place by the anatomic structure 50, twists about itself and forms a coil 44. As the wire twists, the user can pull and/or rock the wire to help seat it snugly around the anatomic structure. At the conclusion of tightening, the wires may be disengaged from the head portion (e.g., by unbending or unwinding), or the wires may be cut (e.g., at cut points 46) to free the wire from the wire tensioner. If untwisted portions of the free ends remain with the patient, they may be trimmed or manually twisted for safety. [0023] The wire typically used for sternal wound closure is No. 5 stainless steel wire (Ethicon Ltd.), which has a diameter of 0.7 mm. However, a wide variety of wires having other sizes and being made of other materials can be used, as appropriate to the application. [0024] FIGS. 6-10 depict alternate embodiments of mechanisms that can fixedly engage the free ends of the surgical wire so that they may be twisted about one another. In FIG. 6, a head portion shaft 31 is shown having two tapered bores 36. The bores should taper at least to a diameter smaller than that of the wire being used, so that the wire ends become lodged in the tapered bores. If, for example, No. 5 stainless steel wire is sued, the bores should taper to less than 0.7 mm. After twisting, the wire ends can be tugged from the tapered bores or cut, as described above. FIG. 7 shows a related embodiment in which, instead of two apertures and bores, there is provided instead one aperture 32' and one tapered bore 37, into which both wire ends may be inserted and seated. The bore can taper to a diameter at least smaller than double the diameter of the wire used. IfNo. 5 stainless steel wire is used, then the bore should taper to less than 1.4 mm. The bore need not be circular in cross section. For example, the bore may have a rectangular cross-section, a rounded rectangular cross-section, an elliptical cross-section, a figure-8 cross-section, or other readily apparent cross-sections. The bore should, however, taper to a size smaller than two free ends. [0025] FIG. 8 shows another embodiment in which the wires may be clamped into the shaft by a clamp 38 that is actuated once the wires are inserted into bores 33'. A wide variety of clamps are known in the art and need not be described here. In another embodiment (not shown), the wire free ends can be placed along the surface of the shaft and clamped against it with, for example, a C-clamp or an a nut threaded over the shaft and wires. [0026] FIG. 9 depicts yet another embodiment in which the head portion includes a proximal portion 31« and a distal portion 316 that are slideably displaceable with respect to one another. When they are slid apart, the wire ends may be introduced in aperture 32' and fit through gaps 33". The proximal and distal portions may then be clamped together, thereby holding the wire ends in place. [0027] FIG. 10 depicts yet another embodiment of a mechanism to fixedly engage the wire ends to the head portion. In this embodiment, the head portion includes at least one bore 39 oblique to the axis of rotation A. The wire ends are threaded through the bore so that the free ends drape out the end. In the depicted embodiment, one bore is provided for each wire. In other embodiments, a single bore may be provided for both wires. When the head portion is twisted, the wires are bent against the bore and thereby held in place. [0028] These embodiments of head portions are merely several examples of the wide variety of fixation mechanisms that may be included to clamp, wedge, or otherwise secure the wire ends at least for the duration of the twisting operation. Other mechanisms are described, for example, in U.S. Pat. Nos. 3,959,960; 5,004,020; 5,379,809; 5,868,748; and 6,041,833, each of which is hereby incorporated herein by this reference.

[0029] 2. The Torque Limiter

[0030] As the wire twists, its resistance to further twisting grows, and greater and greater torque is required to continue twisting. Eventually, the required torque reaches a point that is deemed sufficient to ensure that the wire is adequately tightened but not too tight to cause trauma. At that point, twisting is discontinued, and the wire tensioner may be disengaged from the wire. [0031] The cut-off torque for optimal wire tensioning varies from application to application and from patient to patient. It depends, for example, on the stiffness of the wire, the size, shape, composition, and compressive resistance of the anatomic structure, and other factors. Broadly speaking, the amount of torque required can be within the range of about 0.1 N-m to about 100 N-m, from about 1 N-m to about 10 N-m, and/or from about 5 N-m to about 10 N-m. [0032] One way to limit the amount of torque delivered to the head portion is by manual observation and control. For this approach, the torque driver 20 may include a torque meter 60, as depicted in FIG. 11. The torque meter provides a readout of the amount of torque being delivered to the head portion. As a user applies torque, either by twisting with the hand or by actuating a motor (in the case of a power driver), the user observes the torque meter. A preselected cutoff torque may be indicated on the torque meter to help the user recognize when to cease causing torque to be applied to the head portion. When the torque reaches a desired limit, the user stops applying torque. Although this approach involves manual control, it does permit reproducibility by giving the user an objective indication of the torque applied. [0033] Another way to control the amount of torque delivered to the head portion is by a torque limiter, such as a clutch. A clutch typically has an input shaft and an output shaft that are coupled to one another by way of an intermediate element that decouples the input and output above a certain torque. A very wide variety of clutches and other torque limiter systems have been described in the art. General categories of torque limiters include, for example, the spring-loaded mechanical clutch, the shear pin, the friction-style slip clutch, and the pneumatic clutch. More specific examples include those described in U.S. Pat.

Nos. 1,136,739; 1,566,553; 1,883,164; 2,300,778; 2,746,691; 2,771,171; 2,818,712; 2,885,873; 2,943,216; 3,050,965; 3,053,365; 3,159,725; 3,221,389; 3,277,669; 3,339,819;

3,680,673; 3,701,404; 3,722,644; 3,866,728; 3,893,553; 3,927,537; 3,930,297; 3,930,382;

3,937,036; 3,942,238; 3,942,337; 3,973,784; 3,979,925; 3,981,382; 4,006,608; 4,006,785;

4,014,225; 4,014,488; 4,046,237; 4,088,197; 4,154,308; 4,174,621; 4,463,293; 4,517,863;

4,545,270; 4,576,270; 4,647,260; 4,655,103; 4,671,364; 4,746,320; 4,754,669; 4,766,783; 4,774,863; 4,803,904; 5,044,233; 5,101,697; 5,135,086; 5,156,221; 5,159,987; 5,190,237;

5,239,900; 5,341,704; 5,379,851; 5,380,132; 5,396,975; 5,433,665; 5,524,512; 5,568,753;

5,601,387; 5,682,800; 5,735,183; 5,855,151; 5,865,076; 5,865,499; 5,881,613; 5,915,484;

5,927,163; 5,934,162; 5,943,926; 5,947,210; 5,988,026; 6,089,132; 6,105,450; 6,213,224;

6,244,140; 6,363,818; 6,425,306; 6,439,085; 6,453,780; 6,601,480; 6,647,836; 6,668,690; and 6,715 ,380, each of which is hereby incorporated herein by this reference.

The torque limited can be set or programmed with the preselected cutoff torque.

Claims

I claim:

1. A surgical wire tensioner, comprising: a head portion sized and shaped to fixedly engage two free ends of a surgical wire that is placed around an anatomic structure; and a torque driver, having: a handle so coupled to the head portion as to transmit torque exerted on the handle or generated by the driver to the head portion and thence to the surgical wire ends, thereby twisting the ends about each other; and at least one of: a torque meter to indicate to a user the torque exerted; and a torque limiter to limit the torque that is transmitted to the head.

2. The tensioner of claim 1, wherein the head portion is sized and shaped to fixedly engage two free ends of a number 5 stainless steel surgical wire.

3. The tensioner of claim 1 , wherein the head portion defines two bores, each bore communicating between an aperture on the distalmost end of the head portion and side hole on the side of the head portion.

4. The tensioner of claim 1, wherein the head portion defines two tapered bores, each tapered bore having an aperture opening on the surface of the head portion and terminating inside the head portion.

5. The tensioner of claim 4, wherein each tapered bore tapers to a diameter less than that 0.7 millimeters.

6. The tensioner of claim 1, wherein the head portion comprises a single tapered bore having an aperture opening on the surface of the head portion and being sized and shaped to receive both free wire ends.

7. The tensioner of claim 1 , wherein the head portion comprises: at least one bore to receive the free wire ends; and a clamp positioned to fixedly engage the wires so received.

8. The tensioner of claim 1 , wherein the head portion comprises: a proximal portion and a distal portion slideably displaceable with respect to one another; a clamp engageable between the proximal portion and the distal portion; and a gap between the proximal portion and the distal portion when the portions are not clamped, the gap communicating with an aperture on the surface of the head portion, so sized and shaped to receive the wire free ends and to fixedly engage the wire free ends when the proximal portion and distal portion are clamped together.

9. The tensioner of claim 1 , wherein the head portion defines at least one bore oblique to the axis of rotation of the head portion, the bore sized and shaped to receive one or both free wire ends.

10. The tensioner of claim 1, wherein the torque driver comprises the torque meter.

11. The tensioner of claim 1 , wherein the torque driver comprises the torque limiter.

12. The tensioner of claim 11, wherein the torque limiter comprises a clutch.

13. The tensioner of claim 1 , wherein the torque driver comprises a motor powering the torque driver.

14. The tensioner of claim 1 , wherein the torque driver comprises both the torque meter and the torque limiter.

15. A method of tensioning surgical wire, comprising: placing a surgical wire around an anatomic structure so that the wire ends are free; engaging the wire free ends in a surgical wire tensioner as set forth in claim 1 ; and exerting torque on the handle of the tensioner, thereby twisting the wire ends about each other.

16. The method of claim 15, wherein the torque driver comprises a torque meter, and the method further comprises ceasing to exert torque when the torque meter indicates that a preselected torque has been reached.

17. The method of claim 15, wherein the torque driver comprises a torque limiter, and the method further comprises automatically ceasing to exert torque when the torque meter indicates that a preselected torque has been reached.

18. A method of tensioning surgical wire, comprising: placing a surgical wire around an anatomic structure so that the wire ends are free; engaging the wire free ends in a surgical wire tensioner as set forth in claim 1, the torque driver of the tensioner comprising a motor powering the torque driver; and actuating the motor to exert torque on the head portion of the tensioner, thereby twisting the wire ends about each other.

19. The method of claim 18, wherein the torque driver comprises a torque meter, and the method further comprises ceasing to actuate the motor when the torque meter indicates that a preselected torque has been reached.

20. The method of claim 18, wherein the torque driver comprises a torque limiter, and the method further comprises automatically ceasing to actuate the motor when the torque meter indicates that a preselected torque has been reached.

21. A method of tensioning a surgical screw, comprising: engaging a surgical screw tensioner in the head of a surgical screw to be driven into an anatomic structure, the surgical screw tensioner comprising: a head portion sized and shaped to fixedly engage the screw head; and a torque driver, having: a handle so coupled to the head portion as to transmit torque exerted on the handle to the head portion and thence to the screw, thereby twisting the screw into the anatomic structure; and at least one of: a torque meter to indicate to a user the torque exerted; and a torque limiter to limit the torque that is transmitted to the head; and exerting torque on the head portion of the tensioner, thereby driving the screw into the anatomic structure; and ceasing to exert torque on the head portion when a predetermined torque is reached.

22. The method of claim 21 , wherein exerting torque comprises manually twisting the torque driver.

23. The method of claim 22, wherein the torque driver comprises a torque meter, and ceasing to exert torque comprises ceasing to twist the torque driver when the torque meter indicates that a preselected torque has been reached.

24. The method of claim 22, wherein the torque driver comprises a torque limiter, and the method further comprises automatically ceasing to exert torque when the torque meter indicates that a preselected torque has been reached by decoupling torque transmission from the torque driver to the head portion.

25. The method of claim 21, wherein the torque driver comprises a motor to generate torque, and wherein the step of exerting torque comprises actuating the motor to cause it to generate torque.

26. The method of claim 25, wherein the torque driver comprises a torque meter, and ceasing to exert torque comprises ceasing to actuate the motor when the torque meter indicates that a preselected torque has been reached.

27. The method of claim 25, wherein the torque driver comprises a torque limiter, and the method further comprises automatically ceasing to actuate the motor when the torque meter indicates that a preselected torque has been reached by decoupling torque transmission from the torque driver to the head portion.

28. The method of claim 21 , wherein the torque driver comprises a motor, and exerting torque comprises actuating the motor to exert torque on the head portion of the tensioner.

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