CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application claims priority from Italian patent application no. 102019000003571 filed on 12/03/2019, the entire disclosure of which is incorporated herein by reference .

TECHNICAL FIELD

The present invention concerns a surgical instrument to measure the tension between two soft tissues to be sutured.

PRIOR ART

Surgical suture is a surgical procedure that allows the edges of a wound to be permanently held together, promoting the healing thereof. In particular, surgical suture consists in the application of one or more stitches that keep the edges of the wound in contact; said stitches con consist of knotted suture threads applied by hand, metal staples applied by means of an automatic stapler, synthetic glues (cyanoacrylates) or biological glues (fibrin glue) applied by hand, or also particular sticking plasters (steri strips) applied by hand.

Surgical sutures can be subject to a postoperative complication called dehiscence represented by spontaneous re opening of the previously sutured wound; the dehiscence can be partial, and therefore affect one or some of the stitches, or complete, and therefore affect all the stitches.

In the case of a skin wound, i.e. a superficial wound, possible dehiscence does not entail particularly serious risks for the patient's health, but can have significant aesthetic repercussions since wounds that heal by secondary intention (namely after re-opening) can be subject to hyperplastic scar formation process. One of the main causes of dehiscence of a surgical suture is an excessive tension between the edges of the wound which are held together by the stitches (namely an excessive force necessary to hold the edges of the wound together) ; among other things, an excessive tension between the edges of the wound tends to induce local ischemia of the blood vessels, reducing the blood flow towards the wound and therefore delaying healing. For this reason, before proceeding with application of the stitches, the surgeon must (should) evaluate manually (therefore in an inaccurate and above all totally subjective manner) the tension between the edges of the wound (namely the force necessary to hold the edges of the wound together) and in the presence of an excessive tension should have recourse to appropriate closure techniques that can comprise grafts, local flaps or free flaps.

The correct evaluation of the tension between the edges of the wound normally requires some experience and, in the event of doubt, the intervention (namely the guidance) of a plastic surgeon; however, it is evident that the intervention (guidance) of a plastic surgeon significantly increases the time required to perform the surgical suture and the overall cost of the surgical suture to be borne by the hospital structure .

The patent application US2011009899A1 describes surgical forceps provided with two jaws having one or more force sensors arranged so as to measure the force applied to the j aws .

The patent application EP2011442A1 describes surgical forceps used to separate two adjacent bone segments and comprising both a position sensor to determine the distraction distance between the two bone segments and a force sensor to determine the distraction force that acts on the bone segments when the jaws are opened.

The patent application EP0998877A1 describes surgical forceps provided with two jaws and with a mechanism that fixes the jaws in order to grip the tissue while a measurement assembly determines the tension or the force applied on the tissue.

The patent application US2009188094A1 describes a system for manufacturing a pair of forceps provided with a loading cell configured to measure a compression force between the jaws of the forceps .

The patent application FR3056902A1 describes surgical forceps provided with two jaws hinged to one another, used to clamp a blood vessel; between the jaws a sleeve of elastic material can be arranged in different positions to modulate a clamping force that pushes the jaws towards a closed position and therefore adapt the clamping force to the characteristics of the blood vessel to be clamped.

DISCLOSURE OF THE INVENTION

The object of the present invention is to provide a surgical instrument able to measure the tension existing between the edges of a wound in a simple, rapid and precise manner, and which is, at the same time, easy and inexpensive to produce.

According to the present invention a surgical instrument is provided to measure the tension between two soft tissues to be sutured, according to what is established in the attached claims .

The claims describe preferred embodiments of the present invention forming an integral part of the present description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described with reference to the attached drawings, which illustrate some non-limiting embodiment examples thereof, in which:

• figure 1 is a perspective view of a surgical instrument, produced in accordance with the present invention, to measure the tension between two soft tissues to be sutured;

• figure 2 is a plan view of the surgical instrument of figure 1;

• figure 3 is a perspective view on an enlarged scale of a detail of the surgical instrument of figure 1 according to an alternative embodiment;

• figures 4 and 5 are two schematic plan views, on an enlarged scale, of a further detail of the surgical instrument of figure 1 according to two further embodiments.

PREFERRED EMBODIMENTS OF THE INVENTION

In figures 1 and 2, the number 1 indicates overall a surgical instrument to measure the tension between two soft tissues to be sutured.

The surgical instrument 1 comprises two twin arms 2 which are hinged together to rotate relative to one another around a rotation axis 3 which is arranged in an intermediate position of said two arms 2. Namely, the two arms 2 constitute a lever, the fulcrum of which is arranged at the hinge, i.e. at the rotation axis 3.

Each arm 2 has a holding end 4 provided with a holding member 5 adapted to grip a corresponding soft tissue and an operating end 6 which is opposite the holding end 4 and is designed to be pressed by a surgeon's fingers. In the embodiments illustrated in the attached figures, each holding member 5 consists of (at least) one (skin) hook: in the embodiment illustrated in figures 1 and 2 each holding member 5 consists of a single-pronged hook, whereas in the embodiment illustrated in figure 3 a holding member 5 consists of a single-pronged hook while the other holding member 5 consists of a double-pronged hook. According to a possible embodiment, in the holding members 5 Joseph hooks (or alternatively Gillies hooks) could be used, and in particular a holding member 5 consists of a single-pronged Joseph hook, while the other holding member 5 consists of a double-pronged Joseph hook (namely with two prongs) .

In the embodiment illustrated in figures 1 and 2, each holding member 5 is oriented parallel to the arms 2, while in the embodiment illustrated in figure 3 each holding member 5 is oriented perpendicular to the arms 2. In other words, in the embodiment illustrated in figures 1 and 2, the two hooks that form the two holding members 5 are arranged on slightly different planes but parallel to the plane on which the arms 2 develop; whereas in the embodiment illustrated in figure 3, the hooks that form the two holding members 5 are arranged perpendicular to the arms 2 and also have the function of avoiding the rotation of the surgical instrument 1, stabilizing it in the measurement phase.

Generally the use of the embodiment illustrated in figure 3 is preferable; however, in some situations the embodiment illustrated in figures 1 and 2 may be more convenient and practical .

According to other embodiments not illustrated, the holding members 5 are shaped differently from what is illustrated in the attached figures.

In the embodiment illustrated in the attached figures, each operating end 6 of the surgical instrument 1 is provided with an eyelet 7 for a surgeon's finger. According to a different embodiment not illustrated, the operating ends 6 of the surgical instrument 1 are without the eyelets 7.

In the embodiment illustrated in the attached figures, the surgical instrument 1 comprises a rack 8 which is designed to lock the two arms 2 in a closed position and has: a first part 9 integral to an arm 2 close to the operating end 6, and a second part 9 integral to a second arm 2 close to the operating end 6. According to a different embodiment not illustrated, the surgical instrument 1 is without the rack 8.

The surgical instrument 1 comprises a measuring device 10 which is interposed between the two arms 2 and is designed to measure a return force with which the two holding ends 4 tend to be moved away from one another; in other words, the measuring device 10 is designed to measure the return force which tends to spread the two holding ends 4.

According to a preferred embodiment illustrated in the attached figures, the measuring device 10 is designed to generate a resisting torque that counters a return torque due to the return force (which tends to spread the two holding ends 4) . In particular, during measurement of the return force which tends to spread the two holding ends 4, the resisting torque generated by the measuring device 10 is at least equal to (in an ideal situation exactly equal, but in practice slightly higher than) the return torque due to the return force (which tends to spread the two arms 2) so as to keep the two arms 2 still (in a closed position illustrated in figures 1 and 2) in the absence of external interventions on the arms 2. In other words, during measurement of the return force which tends to spread the two holding ends 4, the resisting torque generated by the measuring device 10 is at least equal to (in an ideal situation exactly equal, but in practice slightly higher than) the return torque due to the return force (which tends to spread the two holding ends 4) so as to keep the two holding ends 4 still (in the closed situation illustrated in figures 1 and 2) in the absence of external interventions on the arms 2. In the embodiment illustrated in the attached figures, the measuring device 10 comprises an elastic element 11 which is designed to push or pull the two arms 2 towards one another to move the two holding ends 4 close to one another (or to move the two arms 2 towards the closed position illustrated in figures 1 and 2 ) .

In the embodiment illustrated in the attached figures, the elastic element 11 consists of a ring of elastic material (for example made of silicone or another elastomer) which is arranged around both the arms 2.

According to other embodiments not illustrated, the elastic element 11 consists of a spring, for example omega-shaped, possibly designed to generate a variable elastic force by modifying a calibration of the spring (for example rotating a screw which modifies the pre-compression of the spring) .

In the embodiment illustrated in the attached figures, the elastic element 11 is movable to vary its distance from the rotation axis 3 and therefore, the elastic force generated by the elastic element 11 being equal, to vary the resisting torque generated by the measuring device 10 due to the variation in length of the arm (or of the distance from the rotation axis 3 of the application point of the elastic force generated by the elastic element 11) . In other words, by moving the elastic element 11 away from the rotation axis 3, the resisting torque generated by the measuring device 10 is increased and vice versa.

In the embodiment illustrated in the attached figures, each arm 2 is provided with a series of notches 12, each of which is designed to house on the inside the elastic element 11. In other words, each notch is a small cavity (or a small recess) obtained on the edge of a corresponding arm 2 (for example with two cuts converging, thus usually forming a V shape) ; the elastic element 11 can be inserted inside two corresponding notches 11 obtained in the two arms 2 to take on a stable and predefined position. According to a different embodiment not illustrated, the notches 12 are not present.

In the embodiment illustrated in the attached figures (at least) one arm 2 is provided with a graduated scale 13 which allows the position of the elastic element 11 to be measured, or allows the distance of the elastic element 11 from the rotation axis 3 to be measured (and therefore allows the resisting torque generated by the measuring device 10 to be measured indirectly) . According to a different embodiment, the graduated scale 13 could also comprise a colouring to indicate the different zones: for example a green colour to indicate the zones corresponding to a reduced tension (and therefore perfectly compatible with a surgical suture without the addition of extra soft tissue) and a red colour to indicate the zones corresponding to a high tension (and therefore not compatible with a surgical suture without the addition of extra soft tissue) .

According to the variation illustrated in figures 4 and 5, the surgical instrument 1 comprises an alignment indicator 14 that visually indicates when the holding members 5 are aligned with one another (or are in a position that determines an alignment between the soft tissues gripped by the holding members 5) . The alignment indicator 14 comprises two reference elements 15 that can be seen by looking at the surgical instrument 1 from above and are arranged at the holding ends 4 of the two arms 2: the alignment of the two reference elements 15 (which can be clearly and easily seen by looking at the surgical instrument 1 from above) indicates that the holding members 5 are aligned with one another (or are in a position that determines an alignment between the soft tissues gripped by the holding members 5) . Preferably, each arm 2 has an appendage that projects in a cantilever fashion from the holding end 4 of the arm 2, protrudes towards the other arm 2 and supports the corresponding reference element 15; obviously the two appendages supporting the reference elements 15 are arranged at different heights so as to at least partially overlap over the alignment position.

In the embodiment illustrated in figure 4, a reference element 15 consists of a through opening (not necessarily of circular shape) through which the other reference element 15 can be seen consisting of a dot (or alternatively any other type of graphic symbol); in particular, figure 4a illustrates a condition of non-alignment of the two reference elements 15 while figure 4b illustrates a condition of alignment of the two reference elements 15.

In the embodiment illustrated in figure 5, both the reference elements 15 consist of a line (or alternatively any other type of graphic symbol); in particular, figure 5a illustrates a condition of non-alignment of the two reference elements 15, while figure 5b illustrates an condition of alignment of the two reference elements 15.

It is important to observe that the two arms 2 can be (slightly) closed also beyond the alignment position indicated by the alignment indicator 14, namely the alignment position indicated by the alignment indicator 14 does not represent the maximum closure possible of the two arms 2, so that starting from the alignment position indicated by the alignment indicator 14 the two arms can be rotated in both directions.

The surgical instrument 1 described above can be used to measure the tension existing between two soft tissues to be sutured; in particular the soft tissues in which the surgical instrument 1 described above can be applied are the skin tissue, the tendon tissue and the muscular tissue. The operation of the surgical instrument 1 is described below with reference to the suture of a skin wound presenting two edges to be brought together.

Before suturing the skin wound, the surgeon uses the surgical instrument 1 to measure in an instrumental and therefore objective manner the tension of the wound, namely the force necessary to keep the two edges of the wound close together: according to the tension of the wound, the surgeon decides the most appropriate closure technique (for example with or without the use of grafts or flaps) and the type of mechanical aid to be used for the suture (for example the type and diameter of the suture thread, metal staples, glues...) .

Initially, and maintaining the surgical instrument 1 open, the surgeon applies the two holding members 5 (namely the hooks) to the two edges of the wound, namely with the two holding members 5 (i.e. with the hooks) the surgeon grips the two edges of the wound to be sutured.

Subsequently, the surgeon closes the surgical instrument 1 until the rack clicks; this step allows for checking whether the elasticity of the soft tissues to be sutured allows the two edges of the wound to be brought close together (namely, it allows a closure rim of the wound to be attained) by applying the closure force that can be generated by the surgeon's fingers acting on the surgical instrument 1. Obviously if the elasticity of the soft tissues to be sutured does not allow the two edges of the wound to be brought together by applying the closure force that can be generated by the surgeon's fingers acting on the surgical instrument 1, then it is not possible to proceed with closure of the edges of the wound by direct suture. Up to this moment, the elastic element 11 is in a neutral position (illustrated in figures 1 and 2) in the area of the rotation axis 3, namely the elastic element 11 does not generate any resisting torque since the arm is nil relative to the rotation axis 3.

Gripping the surgical instrument 1 by the central body in order not to alter the measurement and keeping the surgical instrument 1 closed by means of the rack 8, the surgeon moves the elastic element 11 from the neutral position (illustrated in figures 1 and 2) at the rotation axis 3 to one of the pairs of notches 13, thus moving the elastic element 11 away from the rotation axis 3; once the elastic element 11 is arranged in one of the pairs of notches 13, the surgeon opens the rack 8 and checks whether the surgical instrument 1 tends to open (namely if the resisting torque generated by the elastic element 11 is lower than the return torque due to the tension of the wound which tends to re-open the edges of the wound previously brought together) , whether the surgical instrument 1 tends to close (namely if the resisting torque generated by the elastic element 11 is higher than the return torque due to the tension of the wound) , or whether the surgical instrument 1 is in mechanical equilibrium (namely whether the resisting torque generated by the elastic element 11 is substantially equal to the return torque due to the tension of the wound) .

By moving the elastic element 11 into the various pairs of notches 13, the surgeon seeks the condition in which the surgical instrument 1 is in mechanical equilibrium or, more probably, seeks the two limits of the mechanical equilibrium (namely seeks the two adjacent pairs of notches 13 between which the mechanical equilibrium is found, namely a pair of notches 13 closer to the rotation axis 3 for which the surgical instrument 1 tends to open and an adjacent pair of notches 13 farther from the rotation axis 3 for which the surgical instrument 1 tends to close) .

Reading the graduated scale 13 and using a decoding table (containing an experimental law which links the position of the elastic element 11 to the force that tends to move the two holding members 5 away from one another) , the surgeon estimates the wound tension (or rather, estimates the range of the wound tension) .

The decoding table is obtained experimentally in a laboratory and associates with each pair of notches 13 a corresponding tension value of the wound (namely the force that tends to move away the two holding members 5 secured to the two edges of the wound) ; obviously, the decoding table is set according to the characteristics of the elastic element 11 which could also be chosen from several elastic elements 11 available: in order to measure higher wound tensions (typically in the case of larger wounds), thicker elastic elements 11 are used (which therefore, given the same deformation, generate higher elastic forces), whereas to measure lower wound tensions (typically in the case of smaller wounds) thinner elastic elements 11 are used (which therefore, given the same deformation, generate lower elastic forces) .

According to a simplified form of use, the surgeon does not determine an exact measurement of the wound tension, namely he does not determine a lower tension value and a higher tension value from which the exact measurement of the wound tension is found, but confines himself/herself to checking that the wound tension is lower (it does not matter how much lower) than an upper limit value which indicates the limit beyond which the surgical suture in the absence of a soft tissue graft is at (high) risk of dehiscence. In other words, in the majority of cases the surgeon who has to perform a surgical suture is generally not interested in knowing the exact measurement of the wound tension, he/she is only interested in checking whether the wound tension is compatible with a surgical suture without the addition of extra soft tissue; consequently, the surgeon using the surgical instrument 1 confines himself/herself to checking that the wound tension is lower than an upper limit value which indicates the limit beyond which the surgical suture without addition of extra soft tissue is at (high) risk of dehiscence.

The shape of the arms 2 (in particular at the zones provided with the notches 12) can be modified (for example by moving the two notches 12 of each pair of notches 12 away or closer together) to try to make more linear (and therefore more intuitive) the experimental law which links the position of the elastic element 11 (at each pair of notches 12) to the force that tends to move the two holding members 5 away.

The operation of the surgical instrument 1 is somehow analogous to the operation of the traditional steelyard balance: in the steelyard the balancing weight is moved until reaching equilibrium and the position of the balancing weight at equilibrium is an index of the weight to be measured, whereas in the surgical instrument 1 the elastic element 11 (analogous to the balancing weight) is moved until reaching equilibrium and the position of the elastic element 11 at equilibrium is an index of the wound tension to be measured.

In the embodiment illustrated in the attached figures, the surgical instrument 1 is derived from the Klemmer haemostatic forceps; according to a different embodiment not illustrated, the surgical instrument 1 is derived from the Pean haemostatic forceps or from another type of haemostatic forceps; according to a different embodiment not illustrated, the surgical instrument 1 could be derived from the Castroviejo compass (embodiment preferred when the elastic element 11 consists of an omega-shaped spring) or another type of surgical instrument .

In the embodiment illustrated in the attached figures, the measuring device 10 comprises a movable elastic element 11. According to a different embodiment not illustrated, the measuring device 10 comprises a loading cell (or another sensor designed to measure the force) which is designed to measure the resisting force (namely the force necessary to generate the resisting torque that opposes the return torque due to the tension of the wound which tends to re-open the edges of the wound previously brought together) ; for example, the loading cell could be integrated in the rack 8 (for example interposed between a part 9 of the rack 8 and the corresponding arm 2) to measure the force to which the rack 8 is subjected to keep the two arms 2 (or the two holding members 5) closed. In this embodiment, the surgical instrument 1 could be provided with a screen that displays the measurement carried out by the loading cell or the loading cell could communicate its reading in radiofrequency (for example using the Bluetooth® communication standard) to an external device (for example a mobile phone or a tablet computer) .

The embodiments described here can be combined with one another without departing from the protective scope of the present invention.

The surgical instrument 1 described above has numerous advantages .

Firstly, the surgical instrument 1 described above allows quantitative measurement of the tension created when two soft tissues to be sutured are brought together (for example two edges of a skin wound) ; consequently, the surgical instrument 1 described above provides the surgeon with instrumental and objective numerical data that guide him in choosing the best wound closure strategy, since the tension that is created by bringing together two soft tissues to be sutured is inversely correlated to the probability of rapid and prompt healing (or is directly correlated to the probability of complications) .

In fact, it is now ascertained that a suture that undergoes excessive tension is more subject to delay in healing, dehiscence or, in the case of tendon repair, new rupture.

Furthermore, the surgical instrument 1 described above derives directly from a well-known and widely used surgical instrument, therefore its use is immediate and intuitive for any surgeon by referring to standard handling practices in surgical routine.

Furthermore, the surgical instrument 1 described above is completely compatible with intraoperative use, since it can be fully sterilized at high temperature.

Lastly, the surgical instrument 1 described above has an extremely limited production cost which, among other things, also allows the surgical instrument 1 described above to be produced as a single-use (namely disposable) device; in fact, the surgical instrument 1 described above can be obtained from a simply produced standard surgical instrument 1 with minimum modifications and with the addition of a small number of commercially available parts.

LIST OF REFERENCE NUMBERS OF THE FIGURES

1 surgical instrument

2 arms

3 rotation axis

4 holding end

5 holding member

6 operating end

7 eyelet

8 rack

9 part

10 measuring device

11 elastic element

12 notches

13 graduated scale 14 alignment indicator

15 reference elements