Patent Application
20220211485
The invention relates to a felt material comprising a multitude of fibers for use in a method of repairing or augmenting human or animal soft tissues according to the preamble of claim 1, to a set of surgical instruments for attaching the felt material to soft tissue according to the preamble of claim 25 and to a method of repairing or augmenting human or animal soft tissues according to the preamble of claim 36.
Every year, more than 30 million musculoskeletal injuries are registered worldwide from which nearly half of them involve tendons and ligaments. Common tendon injuries are mostly related to the Achilles and rotator cuff tendons of the shoulder. In the last years more and more scaffold devices, such as extracellular matrix or synthetic grafts were used to mechanically and/or biologically augment repair sites to avoid suture pull-out or elongation which could result in failure. Up to now, sutures are indispensable for medical surgeries for guaranteeing tissue regeneration. The threads used for sutures can vary, depending on the location of the surgery and the targeted tissue. Not only mechanical properties of sutures and knotting techniques are essential for a good outcome. Especially early failure of repaired tendons and ligaments are caused by suture or knot failure where the suture pulling out of the tendon or through the bone. To ideally repair a soft-tissue, high initial fixation strength should be achieved to allow minimal gap formation and mechanical stability to allow a solid healing.
A medical implant for repairing tendons and ligaments is known from US 2008/0188936 A1 [Ball et al.]. This known medical implant comprises an anchor structure attachable to bone by means of bone anchors and a tension member made of a patch material as for example a woven mesh, fabric made by weaving, knitting, braiding or felting fibers. During surgery one end of the tension member is attached to a tendon and then a tension force is applied to the other end of the tension member, which end is then engaged under tension with the anchor structure. A drawback of this known medical implant is that the implant is attached to soft tissue and/or bone at each of its ends only so that a mechanical connection of the implant and the soft tissue or bone is achieved in a small area only.
It is an object of the invention to provide a strong and durable mechanical connection between a felt material and a soft tissue over an extended area of the contact interface between the felt material and the soft tissue to be treated therewith.
The invention solves the posed problem with a felt material for use in a method of repairing or augmenting human or animal soft tissue according to the features of claim 1, with a set of surgical instruments for attaching the felt material to soft tissue comprising the features of claim 25 and with a method of repairing or augmenting human or animal soft tissues comprising the features of claim 36.
The advantages of the felt material for use in a method for repairing or augmenting human or animal soft tissue according to the invention is that a strong mechanical connection between soft tissue and the felt material is achievable in a broad range of the contacting surface resulting in optimal stress distribution.
Further advantageous embodiments of the invention can be commented as follows:
In a special embodiment some of the fibers of the felted patch are pushed or pulled through the second surface into the soft tissue by means of a needle, pin or blade comprising barbs. The barbs catch the fibers of the felted patch or matting and push them through the second surface into the soft tissue. The barbs can be punched, carved or cut into the needle, pin or blade.
In a further embodiment the barbs are spaced at intervals along the needle, pin or blade.
In another embodiment the needle comprises a tip portion and the barbs alternatingly face forward and backward with respect to the tip portion. This configuration permits the advantage that the fibers of the felted patch can be pushed or pulled through the second surface into the soft tissue.
In another embodiment some fibers of the felted patch or matting are pushed or pulled to penetrate through the second surface in the complete area covered by the second surface. The felted patch or matting and the soft tissue can be interwoven in the complete area covered by the second surface so as to form a strong mechanical connection between the felted patch or matting and the soft tissue. The felted patch or matting can be highly loaded in an axial direction, i.e. in a direction parallel to the second surface but can be peeled of if the felted patch or matting is loaded perpendicular to the soft tissue. By this means the felted patch or matting can be repositioned or removed if necessary or beneficial.
In yet another embodiment the second surface of the felt patch or matting is a continuous area, preferably a continuous and flat area. By this means the felted patch or matting is configured to continuously extend over a large contacting area. Depending on its application the felt patch or matting can be configured for a flat connecting area or can be configured as a tubular construct provided with a longitudinal gap to apply the construct e.g. to blood vessels.
In a further embodiment the felt material additionally to the fibers of the felt material comprises fibers or strings of monofilament or multifilament nature and of higher tensile strength or having a larger diameter, wherein the ratio between the tensile force exertable on an additional fiber or string and on a fiber of the felt material is minimum 1.5, preferably minimum 2.0. Therewith the advantage can be achieved that by means of the additional fibers of higher tensile strength or having a larger diameter a higher tensile force can be applied to the felted patch or matting so as to significantly improve the stiffness and patch stability. Furthermore, the complete construct can be reinforced for example if sutures are stitched through the felted patch. An additional advantage is that non-linear stiffnesses can be achieved which are more similar to the natural behavior of tendons and ligaments.
In a further embodiment the additional fibers or strings are in the form of single fibers, a net, a fan or a weave.
In again a further embodiment the felted patch or matting additionally comprises at least a second layer, wherein the at least one second layer is differently configured or comprises a different material than the felted patch or matting. This configuration permits the advantage that a layer providing an anchoring function to the assembly can be added, or a second layer e.g. in the form of a braided structure (mesh or net) to reinforce or augment the felted patch can be added.
In another embodiment the felt material before attachment to soft tissue is pre-stretched in at least one direction along the first and second surfaces of the felted patch or matting. An advantage of this embodiment is that better mechanical properties as higher stiffness of the matting or felted patch can be achieved. Further, the initial fixation strength can be improved to allow minimal gap formation and mechanical stability permitting a solid healing of the soft tissue, e.g. tendon or ligament.
In another embodiment the felt material before attachment to soft tissue is additionally modified by means of a suture arranged with a diagonal stitching pattern. By this means better mechanical properties as higher stiffness of the matting or felted patch can be achieved.
In another embodiment the felted patch or matting comprises one or more augmented zones which each comprise either fibers or strings of monofilament or multifilament nature and of higher tensile strength or having a larger diameter, or a second layer or at least one suture arranged with a diagonal stitching pattern. This configuration permits the advantage that the attachment of the felted patch or matting may be effected in the regions which are not augmented, e.g. not directly on the reinforcement second layer or stitching pattern so as to not destroy the fibers or sutures in the augmented regions.
In a further embodiment the felted patch or matting additionally comprises—before attachment to soft tissue—one or more sutures which are incorporated in the felt material.
In again a further embodiment the one or more sutures—before attachment of the felted patch or matting to soft tissue—protrude from the felted patch or matting so as to form an anchor member. For a direct anchoring function of the felted patch to another member such as bone or cartilage, the patch-suture construct can be equipped with one or several anchor elements which are connected to the felted patch with sutures or other connecting elements.
In another embodiment—before attachment of the felted patch or matting to soft tissue—one end of a braided textile, preferably of a suture is unraveled and reorganized to a felted textile and affixed to the felted patch or matting to form a second layer.
In another embodiment the fibers of the felt material are aligned. This permits the advantage that higher unidirectional stiffness properties of the felt patch or matting can be achieved compared to a common felt material with randomly arranged fibers.
In another embodiment the fibers of the felt material comprise barbs arranged along the fibers, wherein the barbs are preferably integral with the fibers of the felt material. By this means an improved felting effect can be achieved. If bigger monofilament fibers or more likely sutures are used (>∅ 0.3 mm) they can be modified by making cleaves (e.g. in a 30° angle) sidewise to the suture. Those created dual-angle barbs allow the suture to pass smoothly through soft tissue in one direction—but prevent it from slipping back through the soft tissue and make it more likely that they get interwoven and stuck with other fibers of their kind.
In yet another embodiment the felt material is covered or soaked with drugs or chemical agents like antibiotics, biocompatible glue or collagen.
In a further embodiment the felted patch or matting comprises an additional layer of a biocompatible self-adhesive film. This configuration allows a first mechanical connection or later permanent connection of the felted patch or matting to the soft tissue onto which it is attached.
In a further embodiment—during attachment of the felted patch or matting to soft tissue—the needle is guided at an angle different from 90° with respect to the second surface of the felted patch or matting. By means of guiding the needle so as to push or pull the fibers of the felted patch or matting through the second surface at an angle different from 90° towards the surface of the soft tissue a high initial fixation strength can be applied to allow minimal gap formation and mechanical stability permitting a solid healing of the soft tissue, e.g. tendon or ligament.
In a further embodiment—during attachment of the felted patch or matting to soft tissue—the needle is subsequently or alternatingly guided at angles larger and smaller than 90° with respect to the second surface of the felted patch or matting. The fibers of the felt material are crosswise stitched oblique to the surface of the soft tissue.
In a further embodiment more than one felted patch or matting is attached to soft tissue. Several felted patches can be used to connect two tendon ends (e.g. on top and on bottom).
In another embodiment more than one needle is used to displace some of the fibers of the felted patch or matting to penetrate through the second surface into the soft tissue at the same time and preferably from two or more directions.
In another embodiment one or more rotating needles are used to displace some of the fibers of the felted patch or matting to helically penetrate through the second surface into the soft tissue.
According to a further aspect of the invention a set of instruments for attaching a felt material to soft tissue is provided, wherein the set of instruments comprises:
In a further embodiment the stitching device comprises a drive mechanism, wherein the tubular member has a longitudinal axis and the drive mechanism is configured to displace the needle back and forth along the longitudinal axis of the tubular member.
In a further embodiment the first jaw comprises an opening, wherein the opening permits the tip portion of the needle to penetrate the first jaw in the range of the first surface of the felted patch or matting.
In another embodiment the second jaw comprises a mesh covering the cavity, wherein the mesh has openings permitting the needle to pass there through.
In another embodiment the second jaw comprises a plurality of brush fibers arranged in the cavity permitting the needle to pass between the brush fibers.
In again another embodiment the clamping device comprises a holder suitable to be attached to the stitching device, wherein the holder is configured to hold the felted patch or matting and to guide the needle at a selectable angle.
In a further embodiment the drive mechanism is attachable to an electric, pneumatic or hydraulic drive unit.
In a further embodiment the drive mechanism comprises means to adjust an amplitude of the back and forth movement of the needle. By this means the advantage can be achieved that dependent on the size and application different depths of needle penetration into the felted patch and soft tissue can be adjusted by the user. This is particularly useful in combination with a needle which has a defined transportation distance of the fibers that are pushed into the tissue particularly, if there is just a single series of hooks near the tip of the needle.
In a further embodiment the drive mechanism or a drive unit attached to the stitching device comprises means to rotate the needle about the longitudinal axis of the tubular member. By this means rotating or helically penetrating needles can be used with variable rotation of the needle during insertion or extraction.
In a further embodiment the tubular member comprises a hollow ball-shaped front end. This configuration permits the advantage that a better contact surface at the front end is achieved which particularly permits to prevent tilting or tipping over of the tubular member when contacting the surface of the felted patch or matting.
In another embodiment the barbs of the needle are rounded. By this means the cleaning, washing and sterilization processes of the needle are improved so as to provide needles which are particularly suitable for surgical use.
According to another aspect of the invention a method of repairing or augmenting human or animal soft tissues is provided, wherein the method comprises the steps of: A) positioning a felt material in the form of a matting or felted patch comprising a first surface and oppositely arranged a second surface for contacting a surface of soft tissue onto soft tissue of a patient to be treated; and B) repeatedly advancing a needle through the felled patch or matting so that some of the fibers of the felted patch or matting are pushed or pulled through the second surface into the soft tissue by means of a needle producing a connection between the felt material and the soft tissue.
Several embodiments of the invention will be described in the following by way of example and with reference to the accompanying drawings in which:
The above method using a felted patch 9 or matting can be used to reinforce the surrounding soft tissue as a preparation for the use of a conventional suture stitch (tendon-patch). Alternatively, it can also be used to fasten the felted patch 9 to connect it directly to a second target organ (for example tendon-patch-tendon or tendon-patch-bone). Another application is to fasten the felted patch 9, embodied with sutures and or an anchoring element for further fixation to a second structure such as soft tissue (tendon-patch & suture) or bone (tendon-patch & suture-bone anchor).
The felt material 1 applied according to the above method can be used for the repair, augmentation or fixation of anatomical structures such as: suture of collagenous tissues such as tendons or fascias, ligament reconstructions (collateral ligaments, cruciate ligaments, etc.), subcutaneous sutures, conventional suturing of skin closures, skeletal muscle, heart muscle and valves, hollow organs (large vessels, bladder, esophagus, possibly intestine).
Depending on its application:
To get better mechanical properties in terms of higher stiffness of the construct, the felted patch 9 can be pre-stretched and or additionally modified with a diagonal stitching pattern. Furthermore, the felted patch 9 or matting can be covered or soaked with drugs or chemical agents such as antibiotics, a biocompatible glue, collagen or a layer of biocompatible self-adhesive film to allow a first mechanical connection or later permanent connection to the soft tissue 3 on which it is felted on.
As illustrated in
According to the alternative embodiments illustrated in
Another alternative embodiment is illustrated in
The embodiments of
The first jaw 21a is frame-like configured permitting the tip portion of the needle 10 to penetrate the first jaw 21a in the range of the first surface 5 of the felted patch 9 or matting and holding means 28 to hold the felted patch 9 or matting. The second jaw 21b comprises a cavity 29 open towards the first jaw 21a to receive the tip portion of the needle 10. The tubular member 32 has a longitudinal axis 33 and the drive mechanism 31 is configured to displace the needle 10 back and forth along the longitudinal axis 33 of the tubular member 32. The frame-like first jaw 21a comprises an opening 24 which permits the tip portion of the needle 10 to penetrate the first jaw 21a in the range of the first surface 5 of the felted patch 9 or matting.
Furthermore, the tubular member 32 has a hollow ball-shaped front end 40 (e.g. with a diameter between 2 and 10 mm). By this means a better contact surface can be achieved and tilting or tipping over of the tubular member 32 when abutting the felted patch 9 can be prevented.
In a variety of embodiments the drive mechanism 31 of the stitching device 30 can either be induced manually, motorized or by means of pneumatic, magnetic or hydraulic aids. Alternatively, the stitching device 30 can be plugged on a motorized source. The stitching device 30 is configured as a single needle device but—alternatively can be consistent of many needles.
In a further embodiment the drive mechanism 31 or a drive unit (not shown) attached to the stitching device 30 comprises means to rotate the needle 10 about the longitudinal axis 33 of the tubular member 32. Therewith rotating or helically penetrating needles can be used with variable rotation of the needle 10 during insertion or extraction.
In another embodiment the drive mechanism 31 comprises means (not shown) to adjust an amplitude of the back and forth movement of the needle 10 so that dependent on the size and application different depths of needle penetration into the felted patch 9 or matting and soft tissue 3 can be adjusted by the user. This is particularly useful in combination with a needle 10 which has a defined transportation distance of the fibers 2 that are pushed into the soft tissue 3 particularly, if there is just single series of hooks near the tip of the needle 10. In another embodiment, a pair or series of needles can stich consecutively if several needles are used. Parallel stich patters or crosswise patterns can be achieved.
The shape of the needle 10 and the orientation of the felting barbs 11 can be configured to push the fibers 2 of the felt material 1 through the second surface 6 of the felted patch 9 or matting (
Additionally, flat or round shaped needles 10 can be used dependent on preventing tissue damage. The felting barbs 11 can either be oriented in one direction or both linear (circular) directions. This will allow that fibers 2 of the felt material 1 are pushed and/or pulled in both directions (e.g. in a configuration were felted patches 9 are used on top and bottom of soft tissue 3). The felting barbs 11 can either be oriented side to side, in a gradual or circumferential pattern.
The stitching technique can be perpendicular to the soft tissue 3, so that the needle guidance is parallel. In another embodiment the needle guidance is in a certain angle towards the surface of the soft tissue. In another embodiment a crosswise stitching, oblique to the surface is performed. In an embodiment were several felted patches 9 are used to connect two tendon ends (e.g. on top and on bottom) several needles 10 can stich at the same time from two or several directions, each needle 10 equipped with barbs 11.
As illustrated in
As illustrated in
The needle 10 is, exemplarily but not limiting, provided with specially rounded barbs 11 which allows for improved reprocessing after the mechanical production of these needles 10 (cleaning, washing, sterilizing). This configuration is thus particularly suitable for medical applications.
An alternative embodiment of the clamping device 20 for an arthroscopic indication is illustrated in
During attachment of the felted patch 9 or matting, exemplarily but not limiting, more than 2000 fibers/cm2 are pushed through the soft tissue 3. Stress which is applied on the felt construct will be equally distributed on those 2000 fibers which is very attractive for a better healing and against failure of sutures getting pulled tough. in terms of stress distribution of sutures/fibers the felting method according to the invention has an almost 1000-times better stress distribution than conventional suturing methods. Differently oriented felting fibers 2 (isotropic or orthotropic) could be beneficial for cell ingrowth, mimicking the underlying soft tissue 3. A layer of parallel, longitudinal fibers 2 promotes ingrowth of tendon cells while an orthotropic structure promotes ingrowth of heart muscle cells.
In this example illustrated in
A felted patch 9 with the dimension L×W (e.g. 40×40 mm) and a thickness of e.g. 3 mm is tightly enlaced/wrapped around a tendon end 17 and clamped together at its ends. Polyethyleneterephthalate (PET) fibers 2 of the felting patch 9 are a mix of different fiber length (20-60 mm) with a thickness of 5 μm. The patch/suture construct comprises a tear strength of 250N when fully hydrated. The felt patch 9 has a reinforced stitching pattern with PET-yarn 19 (0=0.1 mm) and sewed in sutures 12 (
After that the yet loose tendon-patch construct is placed on a brush mattress and felted with a stitching device which allows to stich 2500 times per minute. The felted patch 9 is now felted onto the tendon 4 by moving and angle the stitching device over the top surface of the felted patch 9 for 30 seconds. After that, the tendon 4 is turned by 180° and the process is repeated with the bottom surface of the felted patch 9. This results in a 380° penetration of the needle 10 and a transportation of more than 10.000 fibers 2 into the tendon 4.
The felted tendon-patch-suture construct can now be implanted into e.g. a bone tunnel and sutures can be enlaced and knotted to a cortical fixation device or suture anchor. The felting method took 60 seconds and avoids time consuming suture (e.g. Mason-Allan stitching) of tendon ends 17, while minimizes the risk of suture pull out of the tendon.
In example 2 as illustrated in
The felted patch 9 has two punched holes 18 with a diameter d of 1 mm, which are reinforced directly at the outer rim of the punched hole 18 with a PET-yarn 19 (0=0.1 mm) in a zigzag pattern, circular and concentric to the punched holes 18. This reinforces the felted patch 9 (if just a felt, comprising of a dense assembly of loose fibers is used, it cannot withstand higher forces [circa 50N]). By reinforcing with a stitching pattern with a yarn 19, the felted patch 9 gains higher stiffness (circa 200N/mm when fully hydrated). In a next step the felted patch 9 is placed on top of a rotator cuff tendon 41 and fixed by means of a clamp into the rotator cuff tendon 41. A 3-sided felting needle (cross-section looks like a triangle) each side having a length of 0.5 mm is used. The total penetration depth of the needle is 20 mm. The needle has a total of 6 barbs, each with a distance of 1 mm separated and a barb depth of 0.1 mm. A stitching device is used which allows to stich 2500 times per minute. The felted patch 9 is now felted onto the rotator cuff tendon 41 by moving the stitching device in a circular way around the punched holes 18, while avoiding to run over the reinforced zigzag pattern (else the barbs of the needle could destroy the yarn). This is done for 30 seconds, resulting approximately in a total of 1250 stitches. Assumed that more than one fiber 2 is pushed down into the soft tissue 3 by means of the needle a manifold of 1250 fibers are pushed town into the soft tissue (5×1250=>6000 fibers). In a last step two USP 2 suture 42 with suture needles and including suture anchors 43 (e.g, to be anchored in a humeral head 44) are used by penetrating the suture needle trough each of the punched holes 18.
If tension is now applied onto the sutures 42, cutting into the soft tissue is now reduced as the reinforced felted patch 9 distributes and absorbs punctual loading.
Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the scope of the appended claims.
It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the invention. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CH2019/000015 | 5/15/2019 | WO | 00 |
