Device and Method to Check the Tension of a Suture During a Surgical Operation

The present invention concerns a device and method to check the tension of a suture during a surgical operation.

The tension must not significantly differ from one suture to another, but this does not mean that it must remain constant, it may vary, for example, between the extremities and the central zone of the suture line. Furthermore, the tension must be appropriate for the type of tissue concerned and the stress to which it is subjected. In practice, suturing depends primarily on the surgeon's dexterity, and requires great precision on his part in evaluating the force and execution of gestures.

The object of the present invention is to check the tension of each suture in order to achieve as even a tension as possible throughout the sutures in view of obtaining the most "natural" wound closure, to promote wound healing and to minimize postoperative complications arising from uneven tension due to excessive tightening or slack such as: astygmatism, embolism, oozing of wounds, etc.

Document EP-A-0115624 describes a device designed to measure the tension of skin fragments during surgery, but it has proven unsuitable for the practical checking of suture tension during an operation.

The present invention is designed to supply and has as an object a device and method utilizable by the surgeon during an operation, and which also allows him to handle the suture before actually checking the tension.

To achieve this result, in summary, the invention consists in a device to check the tension of a suture during a surgical operation, comprising a body, a gripping device to catch hold of the suture, means to actuate the gripping device, and means to signal that the stress, resulting from the displacement of the body by the surgeon and the resistance opposed to such displacement by the tension of the suture held in the gripping device, exceeds a predetermined level, characterized by the fact that the gripping device is mounted on a pivot with respect to the body and that a elastic return means prevents the gripping device from pivoting provided the suture tension does not exceed a predetermined level.

An advantage is that the gripping device can only pivot in one direction, and that pivoting in the other direction is prevented by a stop.

Preferably, the gripping device is a forceps comprising two jaws which can pivot one on the other around an axis which is almost perpendicular to the pivoting axis of the gripping device with respect to the body.

Preferably also, the elastic return means consists in a traction spring or enclosure filled with gas and closed by a mobile plunger. The force of this elastic return means can be adjusted and the means itself is connected to the gripping means by a connecting device, such as a cable, resting on the said gripping device at a point displaced from the pivoting axis with respect to the body.

According to another design, the gripping device is substantially or almost fixed with respect to the body, and the means indicating that the stress exceeds the predetermined level consists of a piezo-electric element or other stress gauge element, and means to produce an information indication signal in response to signals emitted by this element.

These two designs have in common the fact that certain movements are possible, and notably traction along the axis of the body, without causing the relative displacement of the gripping device with respect to the body and in both instances, indications are provided to the surgeon of excessive suture tension.

The invention will now be described in greater detail using a practical, non-exhaustive, example, illustrated with drawings, among which:

FIG. 1 is a side view of a device according to the invention, and

FIG. 2 is a side view, taken at 90.degree. with respect to the orientation of FIG. 1, and a partial section, of the same device.

The illustrated device comprises a longitudinal tubular body 1, of suitable dimensions for correct gripping by the surgeon. At one of its extremities is attached a forceps 2, consisting of a single piece cut to make two jaws 3, 4, connected by a relatively flexible part 5, equivalent to a Y-Y axis articulation. Extremities 6, 7 of the jaws, are classically shaped to allow correct gripping of a suture.

The forceps 2 is mounted on the body 1 by two transverse pivots 8, 9, perpendicular to the longitudinal Z-Z axis of the body 1, and extending towards one another. One of the pivots 8 is fixed, the other pivot 9, can slide in a bore, by the action of a lever 10. The position of the X-X transverse axis of pivots 8, 9 is located between the flexible part 5 of the forceps and extremities 6, 7 of the jaws, such that actuating lever 10 tightens the jaws 3, 4, and grips a suture between 6, 7, if a suture is present.

The opposite end of the body 1 bears a milled knob 11, which is part of a screw system 12, which can be displaced axially (Z-Z) with respect to the body 1. A graduated scale 13 allows the position of the screw system 12 to be precisely adjusted.

If one now considers FIG. 2, one can see that the forceps 2 is shown in one position, in which it is approximately situated along the longitudinal Z-Z axis of the body 1, and in a second position, in which it is at a distance from this axis, with pivoting occurring around the transverse X-X axis of FIG. 1, which passes through pivots 8 and 9. A flexible cable 14 is connected to the screw system 12 through an elastic or resilient traction spring 15. It is also attached to forceps 2 at an anchoring point 16, displaced from or off the axis with respect to pivot 8. The outside surface of the forceps comprises a raised part 17, with an arc-shaped edge on which rests or rides the cable 14. In the resting position, shown in solid lines, in which forceps 2 lies along the axis Z-Z of the body 1, the cable 14 maintains the forces pressed against a stop 18, formed by the edge of an opening made in the top wall of the body 1.

In the position shown in broken lines, in which the forceps lie in position 2', they press against another stop 19, consisting of the edge of another opening made in the side wall of the body. The angle formed by the two limit positions 2, 2' of the forceps is approximately 45.degree.. The limit position 2' corresponds to a frank excess beyond the return force of spring 15, exerted by cable 14. In this position, the anchoring point of cable 14 moves to 16', but because of the arc-shape of the circle of edge 17, the point of application of the force of spring 15 is almost at the same distance from the X-X pivoting axis.

The operating procedure is easy to imagine: before operating, the surgeon adjusts the return force of spring 15 using the milled piece 11, i.e. he adjusts the maximum or limit tension of the suture according to the planned operation. He can then use his forceps as a conventional forceps-needle holder, provided the traction on the suture is exerted along the direction indicated by arrow 20, i.e., towards the left of FIG. 2. If he wants to check the tension of the suture, all he need do is pull on the suture in the opposite direction indicated by arrow 21; i.e. towards the right of FIG. 2. If the tension of this suture is excessive, the forceps will flex or rotate about axis X-X and will tend to change from position 2 to position 2'; this is readily observably indicated, even under a microscope, if microsurgery is being performed. If the surgeon turns the device in his hand halfway around the Z-Z axis of the body, the traction to check the suture will occur in the same direction as the direction of suturing. Further modifications will occur to those skilled in this art, such being considered to fall within the spirit and scope of the invention as defined in the appended claims.