Surgical device, device for pre-bending a buckling wire, method for felting an implant to soft tissue, and method for pre-bending a buckling wire - Patents.com

Abstract

The present invention relates to a surgical device (10) for felting an implant to a soft tissue of a subject. The device comprises at least one felting needle (1) configured to reciprocate. The device comprises a needle protection mechanism for preventing the at least one felting needle from being damaged by contact with a rigid structure during the reciprocating motion. The needle protection mechanism comprises a buckling wire (3) configured to transfer the reciprocating motion from an actuator to the at least one felting needle. The buckling wire is configured to buckle when the at least one felting needle contacts the rigid structure such that the buckling wire is axially compressed.

Description

[Technical field]

[0001] The present invention relates to a surgical device, a device for pre-bending buckling wires, a method for felting an implant to soft tissue, and a method for pre-bending buckling wires. [Background technology]

[0002] The applicant has recently developed a surgical felting device that allows the implantation of biomechanically advantageous implants. The developed device allows improved fixation compared to conventional suturing techniques. An example of such a surgical felting device is disclosed in PCT / CH2019 / 000015. The surgical felting device comprises a needle that is repeatedly moved through a surgical felt into the tissue. By embedding strands of felt inside the tissue, the needle creates a strong, widely distributed mechanical bond between the felt and the tissue. Compared to conventional suturing, this technique is fast to respond and reduces adverse effects such as "cheesewiring" of the suture, i.e. the suture digging into the tissue, which can occur through localized stress peaks.

[0003] However, because surgical felting devices are handled manually and the needles move at high speeds, there is a high risk of needle damage. Damage can result from collisions between the needle and rigid structures such as bones or other surgical tools. Such collisions can lead to partial destruction of the needle (plastic bending, needle breakage, or breakage) that adversely affects its function. Furthermore, parts of the needle can be lost inside the subject's body, posing a health hazard. Summary of the Invention [Problem to be solved by the invention]

[0004] It is an objective technical problem to overcome the above-mentioned shortcomings of the prior art, and in particular to provide a surgical felting device that is safe to use for the operator and the patient. [Means for solving the problem]

[0005] The targeted technical problem is solved by the features of the independent claims. One aspect of the invention relates to a surgical device for felting an implant to soft tissue of a subject, in particular a human. Felting as used herein may be understood as interwining and / or entangling of tissue fibers and implant fibers. Examples of felting needles and their properties are described in PCT / CH2019 / 000015, PCT / EP2020 / 081887, PCT / EP2020 / 081891 and PCT / EP2020 / 081881. The device comprises at least one felting needle configured for reciprocating motion. The felting needle may be a needle with one or more barbs. The barbs may be configured to push individual fibers of the fibrous implant material inwards as the needle is pushed through the implant and into the soft tissue. The reciprocating motion may be understood as a back and forth motion. For example, the needle moves along a line or rotates around an axis at an angle. The implant may be provided with the surgical device and / or may include a fibrous implant material suitable for felting into the soft tissue. The implant may also be provided separately from the surgical device. Exemplary materials and exemplary implants are shown, for example, in PCT / CH2019 / 000015, PCT / EP2020 / 081887, PCT / EP2020 / 081891, and PCT / EP2020 / 081881. Additionally, PCT / CH2019 / 000015, PCT / EP2020 / 081887, PCT / EP2020 / 081891, and PCT / EP2020 / 081881 show surgical devices that can be used in combination with the needle protection mechanisms described herein below.

[0006] Soft tissues may be understood as all tissues in the body that are not hardened by the process of ossification or calcification, such as bones and teeth. Examples of soft tissues that may be felted with implants are soft connective tissues, tendons, skeletal and cardiac muscles, skin, fascia, ligaments, fibrocartilage, especially rotator cuff tendons, Achilles tendons, intervertebral discs, and menisci. A suitable amplitude of the reciprocating motion (i.e., the maximum penetration depth of the at least one needle) may be 1 to 30 mm, more preferably 6 to 15 mm. In a particular example, the amplitude is 8.5 mm, or 12 mm. The exposed tip of the needle (including the barb) may have a length corresponding to the aforementioned amplitude. The at least one felting needle may have a length of the thickness of the implant plus at least 2 mm. In some embodiments, the needle may have a length of at least 4 mm, at least 6 mm, at least 8 mm, or at least 10 mm.

[0007] Additionally, the surgical device may include an actuator for actuating the at least one needle in a reciprocating motion. The actuator may be an electric, mechanical, hydraulic and / or pneumatic motor.

[0008] The device includes a needle protection mechanism for preventing the at least one felting needle from being damaged by contact with a rigid structure during reciprocating motion, the needle protection mechanism including a buckling wire configured to transfer reciprocating motion from an actuator to the at least one felting needle.

[0009] The buckling wire is configured to buckle when at least one felt needle contacts a rigid structure and the buckling wire compresses axially. This allows the buckling wire to absorb the compressive force acting on the needle by bending and prevent the needle from breaking when it hits a rigid structure. This can happen, for example, when the needle contacts a bone of the subject (a bone located in or under soft tissue) or any other hard material, such as another surgical instrument.

[0010] In a preferred embodiment, the buckling force of the buckling wire is less than the buckling force of the at least one felting needle, which ensures that the buckling wire absorbs axis forces.

[0011] In a preferred embodiment, the buckling wire is dimensioned such that the buckling load of the buckling wire is higher than the load at which the at least one felting needle penetrates human soft tissue and is lower than the load required to damage the at least one felting needle. Potential damage to the at least one felting needle may include bending, splintering, and / or breaking of the at least one felting needle. This ensures that the buckling wire can be used repeatedly. Furthermore, this protects the felting needle from harm. To properly dimension the wire, a wire with appropriate mechanical properties (buckling load, Young's modulus) and dimensions (particularly diameter and length) can be selected.

[0012] The buckling load of a buckled wire can be estimated using the following formula:

[0013]

number

[0014] Particularly preferably, the buckling load is 0.1 to 14 N, preferably 2 to 5 to 10 N, most preferably 4.5 to 7 N. These buckling loads are particularly advantageous since they avoid damage to the buckling wire and the felting needles while at the same time allowing the penetration of the soft tissue by the felting needles. The buckling load can be adjusted by modifying the elastic modulus E (e.g. by choosing a suitable material), by varying the cross-section of the wire (e.g. by choosing a circular or angular cross-section, e.g. a square, pentagonal or hexagonal cross-section), and by varying the length of the buckling wire.

[0015] For example, the Young's Modulus may be in the range of 41 to 75 GPa. In another embodiment, the modulus may be 200 GPa. The cross section may be 0.1 to 0.5 mm, 0.1 to 1 mm, 0.1 to 5 mm, 0.1 to 10 mm, or 0.1 to 20 mm. The length of the wire may be 10 to 150 mm, preferably 10 to 50, and more preferably 15 to 40 mm.

[0016] In a preferred embodiment, the buckling wire includes or is made of a shape memory alloy or an elastic soft plastic. For example, the buckling wire includes or is made of Nitinol or a metal alloy or rubber. Examples of plastic materials are rubber-like materials such as PE, PET, nylon, PTFE, silicone rubber. These materials allow for a long life of the buckling wire, allow repeated buckling, and prevent the buckling wire from breaking when a rigid body first contacts it. The shape memory alloy may show a low cycle deformation at high strain that plateaus, for example after 40 cycles. During these cycles, the wire may be bent incrementally more until it reaches a plateau where the deformation becomes constant. The buckling load decreases during the low cycle deformation because the residual bend of the wire increases.

[0017] In a preferred embodiment, the wire has a tube shape and / or includes a cut-out. The presence of the cut-out can prevent the wire from breaking in an undesired place and can define a predefined breaking point to allow for quick replacement of the wire. The tube shape allows for collapsing and buckling. The wire could have a section with a tube shape as a predefined weak point. Additionally or alternatively, the buckling behavior can be controlled by twisting the wire.

[0018] In a preferred embodiment, the device includes one or more further buckling wires, which transfer a reciprocating motion from the actuator to at least one felting. The one or more further buckling wires are configured to buckle when the at least one felting needle contacts a rigid structure. In a preferred embodiment, the one or more further buckling wires are arranged mechanically in series or parallel with the buckling wire and / or in series or parallel with each other. Having multiple buckling wires allows for a more precisely designed buckling load, since manufacturing errors can be averaged out or there can be a failsafe in case one of the multiple buckling wires fails.

[0019] In a preferred embodiment, the buckled wire is dimensioned such that the maximum axial compression of the buckled wire is at least one quarter, preferably at least one half, or at least three quarters, more preferably equal to or greater than the maximum penetration depth of the at least one felting needle, thereby reducing the penetration depth of the at least one needle and preventing the needle from being damaged.

[0020] In preferred embodiments, the maximum axial compression is greater than 1 mm. Preferably, the maximum axial compression is greater than 4 mm, or greater than 6 mm, more preferably greater than 8.5 mm, or greater than 12 mm. Additionally or alternatively, the maximum axial compression is less than 30 mm, less than 20 mm, or less than 15 mm. These ranges allow for comfortable felting while at the same time allowing for more stable wire buckling.

[0021] In a preferred embodiment, the buckled wire is pre-bent. By pre-bending, it is understood that the buckled wire is buckled before use. Pre-bending the buckled wire during production is beneficial since it is already possible to approach or reach said plateau value. Typically, the first bending of the buckled wire requires a higher buckling load than subsequent bending. The buckled wire may therefore be buckled during production and before it is sold, i.e. by subjecting it to multiple deformation cycles, for example 20-40 times. During pre-bending, the wire is slightly plastically deformed, which can be observed by curves and / or internal plastic deformations in the buckled wire.

[0022] In a preferred embodiment, the device includes a buckling chamber in which the buckling wire can buckle. The buckling chamber protects the buckling device from external influences such as contaminants. The buckling wire can be configured to buckle indefinitely within the chamber, or the buckling wire can contact the walls of the chamber so that buckling is limited, such as in axial compression. In the case of unlimited buckling, the load response can be more predictable, while in the case of limited buckling, a more compact design can be achieved.

[0023] In a preferred embodiment, the at least one felting needle and the buckling wire are in particular integrally formed by a single wire. In this embodiment, the needle tip and the barb may be cut directly from the superelastic wire. This provides a particularly simple design. A further advantage is that the at least one felting needle and the buckling wire can be replaced as a unit, which allows for a compact design.

[0024] A further aspect of the present invention relates to a method for felting an implant into the soft tissue of a subject, the method comprising: actuating in a reciprocating motion the felting needle of a surgical device as described above, - contacting a rigid structure with said felting needles; Axial compression of the buckled wire upon contact with the rigid structure to protect the needle from damage due to contact with the rigid structure.

[0025] A further aspect of the present invention relates to a method for pre-bending a buckling wire for a surgical device for felting an implant in the soft tissue of a subject, the method comprising: Providing said buckled wire, preferably said wire made of a shape memory alloy, - attaching said buckling wire to at least two retaining sections (21, 22, 23), buckling the section of the buckling wire between the at least two retaining sections repeatedly, preferably at least 5 times, at least 10 times, at least 20 times, at least 30 times or at least 40 times, by moving one of the retaining sections towards the other; and - preferably inserting the pre-bent wire into a surgical device for felting the implant into the soft tissue of the subject.

[0026] Another aspect relates to an apparatus for pre-bending a buckling wire, the apparatus comprising at least two holding sections for mounting the buckling wire, at least one of the holding sections being movable so as to be able to buckle the buckling wire section between the at least two clamps. [Brief description of the drawings]

[0027] Non-limiting embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: [Figure 1] FIG. 1 shows a perspective view of a surgical device. [Diagram 2] FIG. 2 illustrates a series of steps using the surgical device of FIG. [Figure 3A] FIG. 3A shows the surgical device of FIG. 1 having a first chamber and a corresponding buckling load. [Figure 3B] FIG. 3B shows the surgical device of FIG. 1 having a first chamber and a corresponding buckling load. [Figure 4A] FIG. 4A shows the surgical device of FIG. 1 having a second chamber and a corresponding buckling load. [Figure 4B] FIG. 4B shows the surgical device of FIG. 1 having a second chamber and a corresponding buckling load. [Diagram 5] FIG. 5 shows a diagram of the plastic deformation and buckling load of a buckled wire. [Figure 6] FIG. 6 shows an apparatus for pre-bending the buckling wire. [Figure 7] FIG. 7 shows a cross section of the device of FIG. [Figure 8] FIG. 8 shows a sequence of steps for pre-bending the wire. [Figure 9] FIG. 9 shows the surgical device of FIG. 1 having pre-bent wires. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] FIG. 1 shows a surgical device 10. The device includes a felting needle 1, a distal shaft 2, a buckling wire 3, a proximal shaft 4, and a sliding yoke 5. The distal shaft 2 and the proximal shaft 4 are hollow and have a tubular shape. One section of the felting needle is exposed between the distal shaft 2 and the proximal shaft 4. This section forms the buckling wire 3. The sliding yoke 5 is connected to a motor and moves back and forth along the axial direction of the felting needle 1. During this back and forth movement, the shafts 2, 4 guide the felting needle 1. The shafts 2 and 4 are fixedly attached to the wires that form the felting needle 1 and the buckling wire 3. The buckling wire 3 and the felting needle 1 may alternatively be attached to each shaft and formed individually. In normal operation, the sliding yoke 5 and at least one felting needle move together (together with the buckling wire 3).

[0029] FIG. 2 shows the sequence of steps that occur when at least one felting needle impacts a rigid object. In this case, a load 11 is applied to the needle. The load 11 is greater than the axial forces during normal operation, i.e., greater than the axial forces during felting of an implant to soft tissue. This axial load is transferred to the buckling wire 3 through the tip of the felting needle 1. As can be seen in the second step, the buckling wire 3 reacts by buckling and absorbs the force from the impact. As the yoke retracts, the buckling wire relaxes because the force from the impact is reduced. As long as the obstacle remains, the buckling wire 3 can buckle and relax as indicated by the arrows 12 and 13 in FIG. 2 without breaking. When the buckling wire 3 impacts a hard surface, i.e., a surface with a penetration force higher than the buckling load, it effectively decouples the distal shaft and the felting needle from the translational actuating motion of the proximal shaft.

[0030] Fig. 3A shows a first buckling chamber 6 which can be additionally arranged. The buckling chamber forms a space around the buckling wire so that it can buckle freely. Fig. 3A shows a spherical chamber, but other shapes are also preferred, for example cylindrical or cubicle chambers. The chamber is designed so that the buckling wire does not touch the wall when it is maximally buckled. The maximum extension state of the wire can in particular be found experimentally, for example by holding the tip of a felting needle in its retracted position.

[0031] FIG. 3B shows the relationship between the buckling load (i.e., the load required to compress the buckled wire) and the axial deformation (i.e., the axial compression of the buckled wire). As can be seen from FIG. 3B, a maximum load is required for the initiation of buckling. Before reaching this critical load, e.g., 4.5-7 N, the buckled wire does not buckle. Therefore, felting of the implant into the tissue is not hindered by the buckled wire. Once the critical load is reached, the wire begins to buckle. However, as can be seen from FIG. 3B, the load required to buckle the wire further decreases as the buckling increases. This reduces the load on the needle tip of at least one felting needle, preventing breakage inside the subject's body or due to collision with another surgical instrument.

[0032] FIG. 4A shows a second buckling chamber. The second buckling chamber is formed to form a space around the buckling wire, so that the buckling wire is restrained during buckling. For example, the second buckling chamber can be formed by a tube 7 in which the felting needle 1, the distal shaft 2, the buckling wire 3, and the proximal shaft 4 are placed. Note that in this embodiment, when the buckling wire 3 starts to buckle, a part of the buckling wire may contact the inner wall of the second buckling chamber. This configuration results in a thinner device that can be used in cases where it is difficult to reach soft tissue.

[0033] Figure 4B shows the relationship between the buckling load (i.e. the load required to compress the buckled wire) and the axial deformation (i.e. the axial compression of the buckled wire) for the limited buckling shown in Figure 4A. As can be seen, this limit, i.e. the contact of the buckled wire with the inner wall of the buckling chamber, results in a second peak. In these cases, the critical buckling load of the wire 3 may be the peak resulting from said contact.

[0034] The applicant has noted that the maximum buckling load decreases over time before reaching a plateau. In particular, the first time the buckled wire 3 buckles, a higher buckling load is required than when the wire buckles for the third or fifth time. Without being bound by this, the decrease in the buckling load may be explained by plastic deformation in the buckled wire. However, after many bucklings, the buckling load reaches (approximately) a plateau. This is shown diagrammatically in the graph of FIG. 5. The number of deformation cycles is shown on the x-axis. One deformation cycle is explained by one buckling and relaxation process of the buckled wire. The left graph shows the dependence of the plastic deformation during buckling on the number of cycles, while the right graph shows the dependence of the buckling load required to axially compress the buckled wire on the number of cycles. When the wire is relaxed, the plastic deformation may be observed as a remaining curvature. As can be seen on the right side of Figure 5, the buckling load decreases, but then the buckling load remains constant and reaches a certain plateau. The number of deformation cycles N shown in Figure 5 until the plateau is reached may be 5, 10, 20, 30 or 40.

[0035] It is proposed to pre-bend the buckling wire before use on the subject, for example by repeatedly buckling the buckling wire by several deformation cycles, so that the operator receives a surgical device / felted needle with certain characteristics. A device for pre-bending the wire 3 is described with reference to Figures 6 to 9.

[0036] Figure 6 shows a perspective view of an apparatus 20 for pre-bending a plurality of buckling wires 3. Figure 7 shows a cross section of the apparatus of Figure 6 and Figure 8 shows a schematic diagram of the apparatus, illustrating how the buckling wires 3 are pre-bended.

[0037] The device 20 includes a body 28 and a handle 24 for actuating the device. The handle 24 is connected to a lever 25. The lever 25 has one end connected to the handle 24 and another end connected to a drive shaft 26. The drive shaft 26 is rotatably connected to the body 28 at a bearing 34. The other end of the drive shaft 26 connects to an eccentric 27. When the handle 24 is actuated by rotating it about the bearing 34, the eccentric 27 is actuated (i.e. rotates).

[0038] The device 20 includes a first retaining section 21 and a slide 35 having second and third retaining sections 22 and 23. The second and third retaining sections are fixedly connected to each other by a rod. The slide 35 can move back and forth along a longitudinal direction on a track 29 in the body 28. The third retaining section 23 of the slide 35 also includes a pin 33. The pin 33 is in permanent contact with an outer surface of the eccentric 27. The first retaining section 21 is fixed to the body 28, and the slide 35 and the first retaining section 21 are connected to each other via a resilient element (e.g., a spring 30). The spring is biased such that the slide 35 is permanently urged toward the eccentric 27.

[0039] When the user activates the device with the handle 24, the eccentric 27 rotates. The rotation of the eccentric 27 causes the spring 30 to permanently press the slide 35 against the outer surface of the eccentric 27, thus driving the slide 35 back and forth. In this embodiment, the eccentric 35 has a quadratic shape with rounded edges. However, any other suitable eccentric shape can be used. In this embodiment, one rotation of the handle 35 causes the slide to slide back and forth four times. Additionally, the body 28 includes a removable backplate 36.

[0040] The device 20 includes a handle 24, and in this embodiment the device may be driven by a motor, as is known in the art.

[0041] As can be seen from FIG. 6, the device 20 can receive multiple surgical devices 10 shown in FIG. 1. In this embodiment, the yoke 5 is removed. Before the device 10 is inserted (or after it is inserted in an alternative embodiment), the felting needles may be protected with a tip cover 31 to protect the felting needles and the user of the device 20. Before the surgical device 10 is inserted, the back plate 36 is removed. The surgical device 10 may then be inserted through the first and second retaining sections 21 and 22 from the side of the back plate until the proximal end of the surgical device 10 (the proximal end of the shaft 4) contacts the retaining sections. In some embodiments, any one, two, or all of the retaining sections 21, 22, 23 may include additional means for clamping the surgical device 10. Alternatively, as shown in FIG. 6, multiple surgical devices 10 may be loosely guided by the retaining sections 21, 22, and 23. When the surgical device is fully inserted, the backplate 36 is closed and the tip cover 31 contacts the backplate at the distal end of the surgical device 10. The surgical device 10 is then unable to move along its length.

[0042] When the handle 24 is actuated and the slide 35 begins to move, the third retention section 23 pushes the proximal shaft 4 of the device towards the backplate 36. When the buckling load of the buckling section 3 is exceeded, the buckling section 3 begins to buckle as seen in Figure 8, and this process is repeated multiple times (e.g., 40 times) until the buckling load reaches a plateau as shown, for example, in Figure 5. After the surgical device 10 is pre-bent, the buckling wire 3 may remain curved as seen in Figure 9.

Claims

1. 1. A surgical device (10) for felting an implant to soft tissue of a subject, comprising at least one felting needle (1) configured to reciprocate, the device comprising a needle protection mechanism for preventing the at least one felting needle from being damaged by contact with a rigid structure during the reciprocating motion, the needle protection mechanism comprising a buckling wire (3) that transmits the reciprocating motion from an actuator to the at least one felting needle, the buckling wire being configured to buckle when the at least one felting needle contacts the rigid structure and the buckling wire is compressed axially.

2. 10. The surgical device of claim 1, wherein the wire is sized so that the buckling load of the buckling wire is greater than the load at which the needle penetrates the soft tissue and less than the load required to damage the at least one felt needle.

3. The surgical device of claim 2, wherein the buckling load is 0.1 to 40 N.

4. 10. The surgical device of claim 1, wherein the buckling wire comprises or is made from a shape memory alloy or a resilient soft plastic, and / or the wire has a tubular shape and / or includes notches.

5. 10. The surgical device of claim 1, wherein the device comprises one or more additional buckling wires that transmit the reciprocating motion from the actuator to the at least one felting needle, the one or more additional buckling wires configured to buckle when the at least one felting needle contacts the rigid structure.

6. The surgical device of claim 5 , wherein the one or more additional buckling wires are in mechanical series or parallel with the buckling wire and / or in mechanical series or parallel with each other.

7. The surgical device of claim 1 , wherein the buckling wire is sized such that the maximum axial compression of the buckling wire is at least one-quarter of the maximum penetration depth of the at least one felting needle.

8. The surgical device of claim 1 , wherein the maximum axial compression is greater than 1 mm and / or the maximum axial compression is less than 30 mm.

9. The surgical device of claim 1 , wherein the buckling wire is pre-bent.

10. 2. The surgical device of claim 1, wherein the device comprises a buckling chamber (6) within which the buckling wire is bucklable, the wire and the chamber being configured such that the wire is bucklable without restriction within the chamber.

11. 2. The surgical device of claim 1, wherein the device comprises a buckling chamber (5) in which the buckling wire is bucklable, the wire and the chamber being configured such that upon buckling, the wire contacts a wall of the chamber such that the axial compression is limited.

12. The surgical device of claim 1 , wherein the at least one felting needle and the buckling wire are integrally formed, preferably by a single wire.

13. - actuating a felting needle of a surgical device according to any one of claims 1 to 12 to perform a reciprocating movement; - contacting a rigid structure with said felting needles; - axially compressing the buckled wire upon contact with the rigid structure to protect the needle from damage due to contact with the rigid structure; A method of operating a surgical device for felting an implant into the soft tissue of a subject, comprising:

14. - Providing the buckling wire; - attaching the buckling wire to at least two retaining sections (21, 22, 23); - repeatedly buckling a section of the buckling wire between the at least two retention sections by moving one of the retention sections towards the other; and Inserting the pre-bent wire into a surgical device for felting the implant into the soft tissue of the subject; 13. A method for pre-bending buckling wires for a surgical device according to any one of claims 1 to 12 for felting an implant into the soft tissue of a subject, comprising:

15. 13. A device for pre-bending a buckling wire for a surgical device as described in any one of claims 1 to 12 for felting an implant to the soft tissue of a subject, the device comprising at least two holding sections (21, 22, 23) for holding the buckling wire (3), at least one of the holding sections being movable so that the section of the buckling wire (3) between the at least two holding sections may be repeatedly buckled.

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