WO2007138582A2

WO2007138582A2 - Soft tissue elongation and stretching device and method of use thereof

Info

Publication number: WO2007138582A2
Application number: PCT/IL2007/000642
Authority: WO
Inventors: Yona Kosashvili; Elik Chen; Mordechay Ilovich
Original assignee: Orthogon Technologies 2003 Ltd.
Priority date: 2006-05-31
Filing date: 2007-05-29
Publication date: 2007-12-06
Also published as: WO2007138582A3

Abstract

The present invention relates to devices and methods for stretching and elongating soft tissue(s) by means of an implantable actuator having rotating, or telescopically axially moving, element(s), to which one end of one or more pulling wires are attached, said pulling wires are attached to said tissue(s) with another end thereof, said implanted actuator is actuated by means of an externally applied magnetic field adapted to induce rotary/axial movements of a rotating/reciprocating member movably disposed in said actuator, said movements are transferred to said rotating, or axially moving, element(s) by means of unidirectional clutch(s), ratchet mechanism and gear means thereby causing said pulling wires to retract in response to axial movement of said telescopically axially moving element inwardly into said implantable actuator, or to wound about said rotating element(s), and thus to stretch the tissue said pulling wires are attached to.

Description

SOFT TISSUE ELONGATION AND STRETCHING DEVICE AND METHOD OF

USE THEREOF

Field of the Invention

The present invention relates to a method and device for gradually stretching and elongating soft tissues. More particularly the present invention relates to devices and methods for repairing torn soft tissues by stretching and elongating the same.

Background of the Invention

In several medical conditions, such as Rotator Cuff Tears and Post Operative Ventral Hernia (POVH), soft tissues are retracted/torn. In such cases there is typically a loss of soft tissue continuity, often accompanied by muscle degeneration. In cases of small tears healing of torn tendons can be sometimes accomplished by non-surgical treatments. In the majority of cases surgical treatment is required which aims towards restoration of soft tissue continuity. However, acute surgical repair attempts by use of direct suturing techniques results in high rates of re-rupture and recurrence.

Treatments of torn tendons in the prior art commonly employ bone anchors for suturing the torn tendon to the bone. Many efforts have been made to provide methods and devices for knotless fixation of the torn tissue and for tensioning the suture. For example, methods and devices for treating torn tissues by means of bone anchors are described in WO 06/055823, US 6,524,317, US 2006/0259076, WO 2004/045367, US 6,780,198, US 2006/0116685.

Attempts to surgically repair torn tendons may fail as re- rupture of the torn tendon occur for mechanical reasons. Re- rupture commonly occur due to forces applied on the repaired tendon by limb movements and due to body weight, since the stretching of the torn tissue in conventional surgical treatments often results in excess stress being applied on the torn tissue, which cause loss of flexibility and of stabilizing effect.

Current treatment of POVH consists of either surgical closure of the soft tissue gap or covering it with a synthetic mesh. The downside of the former surgical treatment is the higher chances of re-hernia because of the acute stretching of the separated tissues. The mesh solution has better chances of success, although the POVH is never really covered with the native muscular layers.

There is therefore a need for devices and methods for repairing torn soft tissues and reducing the chances of re- rupture of the repaired tissue.

It is therefore an object of the present invention to provide a method and device for use in the repairing of torn soft tissue that do not apply acute stress on the torn tissue.

It is another object of the present invention to provide a method and device for gradually stretching torn soft tissues.

It is a further object of the present invention to provide a new treatment for repairing torn soft tissues by means of an implantable device actuated externally by magnetic signals.

Other objects and advantages ' of the invention will become apparent as the description proceeds. Summary of the Invention

The inventors herein developed new methods, and devices for carrying them out, for treating torn soft tissues, which reduce the chances of re-rupture of the repaired tissue. In general, the invention aims to provide an innovative treatment for torn tissues wherein the torn tissue is gradually stretched and elongated before suturing the same to connecting tissue (s) or element (s) (e.g., tissue connecting anchors) . The tissue stretching is performed by means of an implantable actuator capable of being actuated by means of an externally applied energizing signal, preferably by means of an axially or rotatably applied magnetic field.

Accordingly, the present invention generally relates to devices and methods for stretching and elongating soft tissues by means of an implantable actuator having rotating, or telescopically axially moving, element (s) to which one end of one or more pulling wires are attached, said pulling wires are attached to said tissues with another end thereof, said implanted actuator is actuated by means of an externally applied magnetic field adapted to induce rotary/axial movements of a rotating/reciprocating member movably disposed in said actuator, said movements are transferred to said rotating, or axially moving, element (s) by means of unidirectional clutch (s), ratchet mechanism and gear means thereby causing said pulling wire to retract in response to axial movement of said telescopically axially moving element inwardly into said implantable actuator, or to wound about said rotating element (s), and thus to stretch the tissue said pulling wires are attached to. The actuator may be transplanted inside a treated limb or shaft, or in any other space in the human body. Said rotating element (s) may include pulleys . - A -

The terms "reciprocate" and "reciprocating movement" used herein refers to an alternately backward and forward linear movement. The term "axially directed magnetic field" refers to a magnetic field directed along the length of the implantable device of the invention. Said axially magnetic filed is pulsating (or alternating) in order to cause the movable element in the implantable device to reciprocate.

In one aspect the present invention is directed to an implantable device for stretching soft tissues comprising a housing having a movable element adapted to rotate or reciprocate (i.e., produce back and forth axial movement) therein in response to an externally applied rotary or axially directed magnetic field, means for transforming the movement of said movable element into a unidirectional rotary or axial movement, and a rotatable or telescopic axially movable member (s) mechanically coupled to said movement transformation means, wherein said rotatable or telescopic axially movable member (s) are attached to said soft tissue by means of a pulling wire.

In one specific embodiment of the invention the movable element is a rod adapted to reciprocate by means of magnetic/ferromagnetic element (s) attached thereto, and by means of corresponding magnetic/ferromagnetic element (s) attached to the inner wall of the housing of said implantable device in response to an axially directed magnetic signals. The movement transformation means may comprise a slidable plunger mechanically linked to said rod and having a return spring, said plunger is engaged via rollers with a rotatable element motion converter (such as helix mechanism) capable of transforming said axial movements into rotary movements. Alternatively, the moving Ferro-magnet mounted on the rod is equipped with linear guidance means fixedly attached to the inner wall of the implantable device, and one end of said rod is mechanically linked by means of rollers to the rotatable element motion converter (helix mechanism) .

The movement transformation means may further comprise gear and unidirectional clutch (s) or a ratchet clutch combination means coupled to said rotatable element. The movement transformation means may further comprise a threaded rotating pivot mechanically coupled to said gear means for translating rotational motions transferred to said threaded pivot from said gear means into linear movements of a moving arm threaded on said threaded rod. Alternatively, the device may be adapted to provide rotary movements directly via said rotating pivot.

According to another specific preferred embodiment of the invention the movable element is a rotatable element having magnetic poles capable of applying tangential forces thereover responsive to an externally applied rotary magnetic field circulating about an axis thereof, thereby causing said rotatable element to rotate about its axis.

In another aspect the present invention is directed to a method for stretching and elongating soft tissues, comprising: anchoring an implantable device as described hereinabove in the treated subject in a location to which tissue elongation is desired, said location may be a gap in the torn tissue (e.g., rectus abdominis muscle), by means of anchoring wires, or in a cavity rimmed in a bone (e.g., humerus medulla), or external to said bone, by means of screws; attaching one end of one or more pulling wires to said soft tissue, attaching another end of said pulling wire to the rotatable or telescopic axially movable member (s) of said implantable device, applying magnetic field signals by means of an external magnetic source placed near or around a portion of the body of the treated subject comprising said implantable device thereby causing said one or more pulling wires to retract due to movements of said rotatable or telescopic axially movable member (s) and stretch said soft tissue, repeating the application of said magnetic field signal until said soft tissue elongated to a desirable length. Optionally, whenever the elongation of the soft tissue is done, suturing said soft tissue to a connecting tissue or to a bone anchor.

Brief Description of the Drawings

The present invention is illustrated by way of example in the accompanying drawings, in which similar references consistently indicate similar elements and in which:

Fig. IA schematically illustrates a preferred embodiment of the invention for stretching and lengthening a tendon by means of an axial activator;

Fig. IB schematically illustrates a preferred embodiment of an axial activator of the invention which is actuated by magnetic signals;

Fig. 1C schematically illustrates another preferred embodiment of an axial activator of the invention which is actuated by magnetic signals;

Fig. 2A schematically illustrates a preferred embodiment of the invention for stretching and lengthening a tendon by means of a rotary activator;

Fig. 2B schematically illustrates a preferred embodiment of a rotary activator of the invention which is actuated by magnetic signals; Fig. 2C schematically illustrates another preferred embodiment of a rotary activator of the invention which is actuated by magnetic signals;

Figs. 3A and 3B schematically illustrate a preferred embodiment of the invention for stretching and lengthening ripped soft tissues;

Figs 4A, 4B, and 4C, schematically illustrate possible embodiments of a rotary activator for stretching and lengthening ripped soft tissues; and

Figs. 5A, 5B, and 5C schematically illustrate possible magnetic activation schemes for the rotary activators exemplified in Figs. 4A to 4C.

Detailed Description of Preferred Embodiments

The present invention aims to provide a method and device for in vivo gradual lengthening of soft tissues. In the present invention the in vivo tissue lengthening is carried out by means of an implantable activator which is activated by externally induced energizing signals, such as magnetic/electric/electromagnetic fields. The induced energizing signals apply mechanical forces to movable elements in the activator which are converted by mechanical means to tensioning forces that gradually elongate (stretch) the respective soft tissues, namely, the muscle- tendon interface.

Fig. IA schematically illustrates a preferred embodiment of the invention for stretching and lengthening tissues such as, but not limited to, tendons. The example illustrated in Fig. IA specifically relates to the treatment of rotator cuff tears. In this preferred embodiment the stretching and lengthening is carried out using an axial activator 56 (e.g., axial activator 18 shown in Fig. IB) . Axial activator 56 may be a type of axial displacement nail implant that is secured to a bone (e.g., Humerus shaft) either intramedullary or extramedullarly, by screws or other securing means, such as, but not limited to, pins, k-wires etc. Pulley 55 (or any other suitable means, such as: metallic/plastic projection, circular pin etc) is rotatably mounted on a lateral side at the upper end (near torn tendon 52) of the axial activator 56, is used for pulling the ripped tendon 52b by means of a pulling wire 53 with minimal friction disturbances.

During surgery one extremity of pulling wire 53 is hooked up to the ripped end 52b of the tendon. The attachment of the ripped tendon 52b to tendon portion 52a attached to the bone 57 may be carried out by suturing in employing any suitable conventional suturing procedure (e.g., using loops, "ears", holes, etc.). The other extremity of pulling wire 53 is passed via pulley 55 and attached to a moving arm 24 (also shown in Fig. IB) of the activator 56. Post operatively, an axial (relative to said activator) magnetic field is applied that causes axial movement of moving arm 24 (designated by arrow 46) which in turn applies stretching forces on the ripped tendon 52b. The applied stretching forces results in predetermined micro movements (e.g., in the range of 0.5 microns to 10 mm, preferably about 0.5 microns) of moving arm downwardly (designated by arrow 46) , which allow the ripped tendon 52b to gradually adapt to its new operative length and tension, rather then performing it acutely. Consequently, when the ripped end of the tendon 52b is close enough (e.g., less than 1 cm from the tendon insertion) it is sutured endoscopically, or in an open manner, to tendon portion 52a attached to bone 57. Fig. 2A schematically illustrates a preferred embodiment of the invention for stretching and lengthening a tissue by means of a rotary activator 66 (e.g., rotary activator 30 shown in Fig. 2B) . In this preferred embodiment the pulling wire 53 is wrapped over pulley wheel (drum) 65 affixed to an upper end of a rotating shaft 23 (also shown in Fig. 2B) . The rotary activator 66 is also operated by applying axial magnetic field signals which are converted in this case to rotary movements of rotating shaft 23.

Fig. IB schematically illustrates an implementation of an axial activator 18 comprising an axial movement actuator 1 based on magnetic force actuation. In this example the activator 18 comprises an axial movement actuator 1 adapted for applying axial movements to a transformation unit 2 (e.g., using a linearly guided plunger having a return spring, which plunger is engaged via rollers with a rotatable motion converter such as helix mechanism) capable of transforming said axial movements into angular movements, i.e., rotary motion. Said angular movements are received by a gear and unidirectional clutch unit 4 (e.g., planetary gear head) via a ratchet mechanism 3, wherein said gear is configured to allow the actuation of the activator 18 with reduced moments. The rotary movements applied by gear device 4 are then transformed into axial movements by the transformation unit 5a (e.g., using a threaded rotating pivot , such as lead screw and nut mechanism, for translating rotational motions of said pivot into linear movements of moving arm 24 threaded thereover) .

Axial activator 18 comprises an elongated hollow body 9 used for housing the various units (1, 2, 3, 4 and 5a) employed therein. In a preferred embodiment of the invention the axial movement actuator 1 is implemented by one or more pairs of stationary magnetic (or ferromagnetic) elements 11 and movable magnetic elements 10, wherein magnetic/ferromagnetic elements 11a, lib,..., Hn, are affixed to the inner wall of body 9, and movable magnetic/ferromagnetic elements 10a, 10b,..., 1On, are affixed to shaft 12 slid-ably centered there inside .

Stationary magnetic/ferromagnetic elements 11 are preferably distributed over a longitudinal section of body 9 with equal distances therebetween, and movable magnetic/ferromagnetic elements 10 are preferably distributed along shaft 12 with corresponding distances therebetween, such that corresponding pairs of stationary and movable magnetic/ferromagnetic elements ({10a, Ha), {10b, lib},...) are obtained.

Stationary magnetic/ferromagnetic elements 11 are configured to provide a concentric passage suitable to slidably comprise movable rod 12. Each stationary magnetic/ferromagnetic element 11 preferably occupies a circumferential cross- sectional area of hollow body 9 while providing a passage thereinside, where the passage of the adjacent stationary magnetic/ferromagnetic elements 11 are centered about the longitudinal axis of elongated body 9. In this way shaft 12 may be moved horizontally, as exemplified by arrow 7, by applying a magnetic field along the longitudinal axis of elongated body 9, which in turn cause attraction forces to develop between each pair of stationary and movable magnetic/ferromagnetic elements 11 and 10.

Elongated body 9 is preferably a hollow cylindrical body manufactured from a non-magnetic material such as S.S316LVM or Titanium alloy. Its length is generally in range of 30 mm to 400 mm, preferably about 100 mm. The outer diameter of body 9 is generally in the range of 6 mm to 12 mm, preferably about 10 mm, and its inner diameter in the range of 4 mm to 8 mm, preferably about 7 mm. Stationary magnetic/ferromagnetic elements 11 are preferably cylindrically shaped elements manufactured from ferromagnetic or magnetic material, such as carbon steel or industrial Ferromagnetic alloy, preferably from VACCOFLUX 50, SAElOlO, SAE1018, or SAE1020, Carbon steel. The diameter of stationary magnetic/ferromagnetic elements 11 is determined to allow fitting thereof in the hollow interior of elongated body 9. The bore in stationary magnetic/ferromagnetic elements 11 is configured to allow movable rod 12 to move therethrough, for example, said bore may be in the range of 1 mm to 3.5 mm, preferably about 2 mm.

Movable rod 12 may be manufactured from Stainless steel or Titanium alloy, preferably from S.S316LVM. The length of movable rod 12 is generally in range of 20 mm to 80 mm, preferably about 30 mm, and its diameter is generally in range of 1 mm to 3 mm, preferably about 1.6 mm. The distance between pairs of magnetic/ferromagnetic elements (e.g., the distance between magnetic element 10a and 10b) along the longitudinal axis of elongated hollow body 9 is generally in range of 6 mm to 20 mm, preferably about 11 mm. The gap between the stationary magnetic/ferromagnetic elements 11 and the movable magnetic/ferromagnetic elements 10 is generally in range of 0.4 mm to 2 mm, preferably about 1.2 mm, and the axial magnetic forces which evolve therebetween during operation of the actuator may bring said elements to come into contact. The magnetic field applied during operation may typically be in the range of 0.03 to 0.1 Tesla, preferably about 0.075 Tesla.

Fig. 1C illustrates another implementation of the implantable actuation wherein the axial movement actuator I¹ comprises one movable magnetic/ferromagnetic element 10' attached to shaft 12, and one stationary magnetic/ferromagnetic element 11' attached to the inner wall of axial activator 18' (e.g., by means of welding or pins) . The movable magnetic/ferromagnetic element 10' is linearly guided by rollers/bearings 14 fixedly attached to the body 9 by pins 15. The moveable rod 12 is secured to the moving magnetic/ferromagnetic element 10' by threading, or welding, or other suitable means. The return spring 8 returns the movable magnetic/ferromagnetic element 10' forwardly (to its initial starting point) whenever the applied magnetic signals are minimized, zeroed, or reversed. The shoulder 13 and the rear tube plug 6 confine the loaded spring volume. When the magnetic/Ferromagnetic elements, 10' and 11' are energized the movable magnetic/ferromagnetic element 10' is attracted backwardly towards the stationary magnetic/ferromagnetic element 11' . This linear motion is converted into rotary motion through out the rollers 16 which are coupled with the helix slots 17.

Fig. 2B schematically illustrates a preferred embodiment of a rotary activator 30 designed to be activated by a magnetic driving source. Rotary motion magnetic activator 30 may be constructed with similar components as in the axial magnetic activator 18 described hereinabove with reference to Figs. 2A and 2B. In this implementation, however, rotary magnetic activator 30 outputs rotary motion (designated by arrow 27) directly via rotating pivot 23. The rotary motion applied by rotary magnetic activator 30 is outputted directly via rotating pivot 23 (rotary movement transfer unit 5B) linked to gear and unidirectional clutch unit 4. The end tip of pivot 23 may protrude outwardly via an opening of elongated hollow body 9a. The main difference between axial activator 18 and rotary activator 30 are in that the rotary movements of pivot 23 are outputted directly in rotary activator 30 by means of rotary movement transfer unit 5b, while in axial activator 18 the rotary movements of pivot 23 are translated into axial movements by means of moving arm 24 (in transformation unit 5a) movably threaded thereover.

Fig. 2C is illustrates a rotary activator 30' which axial movement actuator 1 employs a movable magnetic/ferromagnetic element 10' and a stationary magnetic/ferromagnetic element II¹, as in the axial activator 18' illustrated in Fig. 1C. In principle, the operation of rotary activator 30' is similar to the operation of axial activator 18'. However, in rotary activator 30' shown in Fig. 2C the rotary movement of rotating pivot 23 is outputted directly.

Various implementations of magnetic activators are described in detail in international patent application No. PCT/IL2006/000888, published under publication No. WO 2007/015239, the content of which is incorporated herein by reference. Alternatively, the activator used in the device of the invention may be driven using other wirelessly energizable means, such as linear or rotary piezoelectric motors (e.g., Nanomotion linear piezo electric), motors that may be actuated by an externally applied alternating magnetic or electromagnetic field (e.g., rotary synchronized magnetic or electromagnetic field which could drive a permanent invasive core) .

In the example shown in Figs. ,1A and 2A, the activator may be transplanted inside the humerus medullary cavity, which may be rimmed to accommodate the activator's external diameter. The activator is preferably inserted to bone 57 from above into the humerus medullary cavity and thereafter fixated to the bone by tightening screws 58.

In the embodiments illustrated in Figs. IA and 2A, pulley (65 or 55) may be assembled onto the rotary (66) or axial (56) activator only after inserting the activator into the cavity in bone 57, in order to ease the insertion procedure of the activator. The ripped tendon 52b (or tendons), or portions thereof, may be then stitched to the pulling wire 53 which is hooked up to fixated pulley wheel 65 in the case of the rotary activator 66 (Fig. 2A) , or to the moving arm 24 in the case of the axial activator 56 (Fig. IA) .

The rotary/axial activators of the invention may be transplanted inside a treated limb or shaft or any other space in the human body. During magnetic activation the treated area is inserted into a ring shaped coil which, when energized, induces a magnetic field in an axial direction relative to the activator that attract/repulse the ferromagnetic and/or permanent magnet elements. In another possible activation approach, especially useful when the treated implant is adjacent the external surface of the body, or when a low magnetic force is required for a specific application, is to activate a plane formation magnetic field such as "U" shape iron core wounded with a coil that^' induces a magnetic flux between the two magnetic poles . This magnet may be then placed near the treated area such that the generated magnetic field is induced in the activator in the proper axial direction required for its activation.

The applied magnetic field is a pulsating field having a frequency generally in the range of 0.5 to 5.0 Hz, preferably about 1 Hz. A typical example is that each pulse of the applied pulsating magnetic field may comprise an ON (0.2 to 1 sec) and OFF (0.5 to 1 sec) time periods, wherein during the OFF time periods the power of the applied magnetic filed is minimized or zeroed. Alternatively, during said OFF time periods the directions of ' the applied magnetic field is reversed.

In the case of the axial activator 56 (Fig. IA) a magnetic field applied thereto causes the moving arm 24 of the activator 56 to retract (i.e., to move into the cavity of the axial activator 56) , such that pulling wire 53, passed via pulley 55 and hooked to moving arm 24, is gradually pulled towards bone 57. In the case of the rotary activator 66 (Fig. 2A) , the magnetic field applied thereto causes the rotating pivot 23, and pulley wheel 65 fixedly attached thereto, to rotate about its axis, such that pulling wire 53, hooked to pulley wheel 65, is progressively wounded thereabout.

In a preferred procedure, the activator is transplanted in bone 57 as follows: The tip of the medullary canal of the humerus is opened using an owl tip. This can be done either under fluoroscopy, under arthroscopy or under direct vision. The medullary canal is reamed over a guide that inserted into the medullary canal to fit the activator. Once the canal is prepared, the activator that is connected to a targeting handle is inserted. Preferably, the targeting device^' will be well secured to the activator in order to allow insertion of locking/tightening screws to secure the activator to the humerus bone.

After transplanting the activator in bone 57, a series of sessions are carried out during which axial (relative to said actuator) actuating magnetic field signals are applied by a source of magnetic signals for applying gradual stretching of the torn tendon. The patient will go through several (1-12, preferably 4) magnetically actuating sessions a day, until the soft tissue gap is closed. Each session will be composed of 1-1000, preferably 250, actuations. Once the gap is sufficiently bridged, allowing a direct closure, the surgeon will decide whether an additional surgery is required to close the gap or to allow the soft tissues a trial period to spontaneously scar down in the approximated position. If an additional surgery is performed than the surgeon can decide based on intra operative findings whether the activator should be removed at that time. Surgical closure of the gap can be performed in any of the common surgical techniques currently in use, either arthroscopically or in an open manner.

Figs. 3A and 3B schematically illustrate a tissue stretching implementation configured for pulling adjacent tissues, 72a and 72b, (e.g., adjacent portions of the rectus abdominis muscle) , one towards the other, for closing a gap 77 formed therebetween, as may be required in cases of POVH. In these implementations the implantable activator 75 employed is activated by a rotating magnetic field, as will be described in detail hereinbelow. Alternatively, the operation of the implantable activator 75 may be driven using other wirelessly energizable means, such as electrical, linear or rotary piezoelectric motors (e.g., Nanomotion linear piezo electric) , motors that may be actuated by an external applied alternating magnetic or electromagnetic filed (e.g., rotary synchronized magnetic or electromagnetic field which could drive an invasive permanent core) , or by using a permanent magnet rotor (step motor) , a preloaded spring mechanism, or an external intervention, such as screws, rods, wires etc.

The implantable activator 75 comprises a housing 70 secured by anchoring wires 79 to opposite ends 77u and 77d of the gap 77. The tissue stretching is not applied by anchoring wires 79 to said opposite ends 77u and 77d of gap 77, in order to prevent displacements thereof. For example, the housing 70 may be secured to both the proximal and distal lesion ends. A rotatable magnetically activated mechanism situated in said housing 70 activates one or more pulleys 73a, 73b,..., to which the ends of several pulling wires 76 are attached, wherein the other ends of said pulling wires 76 are attached to the tissues to be stretched (72) . For example, in case of POVH, sutures from the right and left tendinous part of the rectus abdominis are attached.

Fig. 3A demonstrates the stretching of opposing tissues, 72a and 72b, toward each other by means of two vertically aligned pulleys, 73a and 73b, which are rotated in the same direction and configured to pull two pulling wires, 76a and 76b, attached thereto and to opposing points in said tissues. The pulling wires are anchored to the pulleys by conventional means such as end cup devices which are laser welded or plastically squeezed with the pulling wire. The end cup is coupled to the pulley via a designated recess. The pulling wires are sutured into the tissues using one or more standard heavy sutures in use for tendon suturing such as ethibond, for example. The sutures are connected to the activator either pre fixed to it before the activator is inserted or secured to it during the surgical procedure. Any type of standard suture fixation of sutures to implants can be used such as hoops, hooks, holes etc.

Fig. 3B demonstrates a similar implementation (wherein the two or more pulleys 73 rotate in the opposite direction wherein a number of pulling wires 76 are attached to each pulley, 73a, 73b. The attachment of the pulling wires 76 to the tissues 72 is preferably made at opposing symmetric points on the tissues in order to cancel (hang over moments) displacing moments which may be induced during the stretching of the tissue. Activation of the external rotating magnetic field creates a gradual force that approximates both Tissues 72a and 72b, allowing a higher success rate of a definitive surgical closure of the gap 77, without requiring artificial means such as a mesh etc.

The housing 70 of implantable activator 75 is preferably implemented by a hollow structure having substantially cylindrical or oval cross-sectional shape. Housing 70 may be manufactured by casting or lathing process, from a biocompatible material, such as, but not limited to, S. S316LVM or Ti alloys. The diameter of housing 70 may generally be in the range of 10 to 40 mm, preferably about 30 mm, and its length may generally be in the range of 4 to 15 mm, preferably about 7 mm.

Pulleys 73 are preferably manufactured by lathing, from biocompatible material, such as, but not limited to, S.S316LVM or Ti alloys. The diameter of pulleys 73 may generally be in the range of 5 to 15 mm, preferably about 8 mm. Different types of surgical wires may be employed for pulling wires 76, preferably a type made of non absorbable heavy sutures, such as, but not limited to, Mersaline or Ethibond wire.

Figs. 4A to 4C schematically illustrate various embodiments of the implantable activator 75 of the invention that are configured for stretching adjacent tissues 72. In principle, these embodiments comprise a 'Ferromagnetic and/or permanent magnet elements 83 (e.g., a rod shape, "U" shaped) driving a rotary unidirectional clutch or ratchet 88 with pawl 85 mechanism (to prevent unwanted backwards rotations) , which is coupled via a planetary gear head 87 (or any other gear) to one or more pulleys 73. Pulley (s) 73 are driven through an interim gear train, friction driving, belt/wire driving, or similar motion transferring means. The activator 75 is actuated via an external rotating magnetic field. The permanent magnet used in the activator aligns itself with the direction of the external rotating magnetic field and consequently rotates the rest of the mechanism.

Ferromagnetic/magnetic element 83 may be manufactured from a type of carbon steel or iron material, such as, but not limited to, SAE1020, SAElOlO, preferably from SAE1020. By way of example, in a specific embodiment ferromagnetic/magnetic element 83 is made in a shape of a cylindrical rod having a length generally in the range of 5 to 15 mm, preferably about 12 mm, and having a diameter generally in the range of 3 to 6 mm, preferably about 5 mm. Rotary unidirectional clutch or ratchet 88 and pawl 85 mechanism is preferably implemented by a toothed wheel made from stainless steel, such as, but not limited to, S.S316L, PH17-4, preferably from S.S316L, having a diameter generally in the range of 6 to 15 mm, preferably about 10 mm, and thickness generally in the range of 1.5 to 3 mm, preferably about 2 mm. Pawl 85 is fixedly attached at one end thereof to the inner wall of housing 70 while its other end is engaged with the toothed wheel. Pawl 85 may be manufactured from spring type stainless steel such as S.S302.

The activator 75' shown in Fig. 4A comprises a permanent magnet 83 element rotatably turned about a pivot 49 comprising a ratchet (88) and pawl (85) mechanism. The ratchet and pawl mechanism ' (88, 85) allow rotation of permanent magnet 83 and pivot 49, to which magnet 49 affixed, in one direction only. A planetary gear head 87 is coupled to pivot 49 via respective pinion gear wheel - 49w fixedly attached to pivot 49, and 87a and 87b rotatably attached within planetary gear head 87. A portion 78p of the gear head shaft 78 of the planetary gear head 87 rotatably and sealably protrudes via an opening ' provided in the housing 70' (chassis), such that pulley wheel 73 can be fixedly mounted thereon.

The whole internal volume of housing 70' is preferably sealed by Silicone 0-rings (not shown) which surrounds the gear head shaft 78.

The structure of the implantable activator 75' ' shown in Fig. 4B is different from the above described implantable activator (75') mainly in that the rotations of the gear head shaft are transferred to two pulleys, 73a and 73b, mounted on respective pulley shafts, 73aa and 73bb, rotatably and sealably mounted in the upper wall of activator 75' '. In this case the gear head shaft 87s of planetary gear head 87 is coupled to the pulley shafts, 73aa and 73bb, via respective transmission wheels, 86w and 84a and 84b, mounted on gear head shaft 49 and on each of the pulley shafts, 73aa and 73bb. Activator 75'' output pulleys, 73a and 73b, are rotated in the same directions.

The activator 75' '' shown in Fig. 4C also comprises two pulleys, 73c and 73d, but in this case one pulley (73c) is mounted on a portion 82p of the gear head shaft 82 protruding outwardly via the upper wall of the housing 70' ' ' and the other pulley (73d) is mounted on a pulley shaft 73dd also mounted on the upper wall of the housing 70' ' ' . Suitable transmission wheels, 86w fixedly mounted on gear head shaft 87s, and 86u fixedly mounted on pulley shaft 73dd, are used for transferring the rotation of the gear head 87 to the pulleys, 73c and 73d, respectively. In this case the output pulleys, 73c and 73d, are rotated in^! opposite directions.

The activator 75 may be transplanted in the body of the treated subject using anchoring wires 79 to place it in the treatment site and pulling wires 76, said wires are preferably made of non absorbable heavy sutures, such as, but not limited to, Mersaline or Ethibond, to connect the pulley (s) to the tissues to be stretched, as demonstrated in Figs. 3A and 3B. For example, in the case of POVH, The device is inserted into the belly space and it is then attached therein to the treated tissues by means of anchoring and pulling wires. The spaced apart rectus abdominis tissues are attached to the pulley (s) using pulling wires and when the pulleys are rotated the pulling wires wound around them and gradually pull the two belly segments towards the center. Various ways for applying a rotating magnetic field will be now described hereinbelow with reference to Figs. 5A to 5C.

As shown in Figs. 5A to 5C the magnetic field actuating the implantable device shown if Figs. 4A to AC may be applied in various ways. Fig. 5A demonstrates the use of a rotary coil system 99 wherein a "U"-shape core 90 (e.g., made from iron) is wound with a coil 92 such that a magnetic field (B - designated by arrow 91) is obtained between the arms of the "U"-shaped core 90 whenever the coil is energized by an electric current (I - designated by arrows 93) . The "U"- shaped core 90 may be rotated externally about a pivot 96 attached to its base, for example, manually, or by means of a gear-motor, pneumatic motor etc. The rotations of the "U"- shaped core 90 causes rotation of the magnetic field (B) obtained between its arms, thereby providing the activating rotating magnetic field required. In the example shown in Fig. 5B two (or more) "U"-shaped cores, 90a and 90b, comprising coils, 92a and 92b, are used. This configuration may be used to create variable magnetic field directions as follows:

To gain sequenced quadruple orientation the coils will be energized as follows:

• 90° - Coil #1 92a is energized with a current Il (93a) thereby inducing magnetic field in direction A (91a) ;

• 180° - Coil #2 92b is energized with a current 12 (93b) thereby inducing magnetic field in direction B (91b) ;

• 270° - Coil #1 92a is energized with a current -Il thereby inducing magnetic field in direction opposite to A;

• 360° - Coil #2 92b is energized with a current -12 thereby inducing magnetic field in direction opposite to B.

Sub deviations of 45°, 135°, 225° and 315° may be achieved by simultaneously energizing both coils, 92a and 92b, with current polarities corresponding to the field direction needed.

Fig. 5C demonstrates using an externally rotatable permanent magnet 90' for inducing the required rotating magnetic field B (91) . As with the "U"-shape magnets, or cage shape (or any other structure that creates a planner formation magnetic field), when the external permanent magnet 90' is rotated about pivot 96 near the treated site, the magnetic element 83 in the implanted activator 75 rotates, correspondingly.

The "U"-shape core(s) 90 illustrated in Fig. 5A to 5C are preferably made from iron, or Nickel, or from laminated Ferromagnetic foils materials which are characterized by high permeability values. The length of the base of "U"-shape core(s) 90 may generally be in the range of 20 to 100 mm, preferably about 50 mm, and the length of its arms may generally be in the range of 10 to 60 mm, preferably about 30 mm. Said "U"-shape core(s) 90 having a thickness generally in the range of 15 to 60 mm, preferably about 30 mm. The magnetic field produced by magnetic field actuators shown if Figs. 5A to 5C is generally in the range of 0.01 to 0.08 Tesla, preferably about 0.05 Tesla, and the speed of rotations during a typical session may generally be in the range of 10 to 240 RPM, preferably about 15 RPM.

In a preferred procedure, the abdominal POVH is surgically approached and appropriately exposed. The implant is secured to the POVH edges with the respective sutures. For example, anchoring sutures to the superior and inferior poles of the POVH and tensioning sutures to the medial and lateral edges. If the surgeon decides the tensioning should be performed not mediolateral but in a different direction, than the sutures should be correspondingly attached. Once the activator is secured, surgical closure of the incision is performed according to the soft tissue layers, in a standard fashion.

After transplanting the activator in a tissue gap 77, a series of sessions are carried out during which rotating actuating magnetic field signals are applied by a 'source of magnetic signals for progressively stretching the sides of the torn tissue towards each other. The patient will go through several (1-12, preferably 4) magnetically actuating sessions a day, until the soft tissue gap is closed. Each session will be composed of 1-1000, preferably 250, actuations. Once the gap is sufficiently bridged, allowing a direct closure, the surgeon will decide whether an additional surgery is required to close the gap or to allow the soft tissues a trial period to spontaneously scar down in the approximated position. If an additional surgery is performed than the surgeon can decide based on ^'intra operative findings whether the activator should be removed at that time. Surgical closure of the gap' can be performed in any of the common surgical techniques currently in use, either arthroscopically or in an open manner.

It should be noted that the embodiments exemplified in the Figs, are not intended to be in scale and are in diagram form to facilitate ease of understanding and description. In fact, scale may vary from one portion to another of each Fig.

The above examples and description have of course been provided only for the purpose of illustration, and are not intended to limit the invention in any way. As will be appreciated by the skilled person, the invention can be carried out in a great variety of ways, employing more than one technique from those described above, all without exceeding the scope of the invention.

Claims

1. An implantable device for stretching soft tissues, comprising: a housing having a movable element disposed therein, said movable element is adapted to rotate or reciprocate in response to an externally applied rotary or axially directed magnetic field signals; means for transforming the movement of said movable element into a unidirectional rotary or axial movement, and a rotatable or telescopic axially movable member (s) mechanically coupled to said movement transformation means, wherein said rotatable or axially movable member (s) are attached to said soft tissue by means of a pulling wire thereby allowing stretching of said soft tissue by the application of rotary or axially directed magnetic field signals.

2. The implantable device according to claim 1, wherein the movable element is a rod adapted to reciprocate inside said device .

3. The implantable device according to claim 2, wherein the rod comprises one or more magnetic/ferromagnetic element (s) attached thereon and adapted to apply mechanical forces thereover in response to axially directed magnetic field signals.

4. The implantable device according to claim 3, wherein one or more magnetic/ferromagnetic element (s) are attached to the inner wall of the housing of the implantable device.

5. The implantable device according to claim 2, wherein the movement transformation means comprise a slidable plunger mechanically linked to the rod and having a return spring, said plunger is engaged with a rotatable element capable of transforming said axial movements into rotary movements.

6. The implantable device according to claim 2, wherein the movement transformation means comprises a rotatable element mechanically linked to the rod and adapted for transforming its axial movements into rotary movements, wherein a return spring is mechanically attached to said rod for restoring its initial location.

7. The implantable device according to claim 5 or 6, wherein the movement transformation means further comprise gear and unidirectional clutch (s) or ratchet means coupled to the rotatable element.

8. The implantable device according to claim 5 or 6, wherein the movement transformation means further comprise a threaded rotating pivot mechanically coupled to the gear means for translating rotational motions transferred to said threaded pivot from said gear means into linear movements of a moving arm threaded said threaded rod.

9. The implantable device according to claims 5 or 6, wherein the movement transformation means further comprise a rotating pivot mechanically coupled to said gear means for transferring the rotational motions transferred thereto from the gear means.

10. The implantable device according to claim 1, wherein the movable element is a rotatable element having magnetic poles capable of applying tangential mechanical forces over said element responsive to an externally applied rotary magnetic filed.

11. A method for stretching and elongating soft tissues, comprising: anchoring an implantable device, as of the present invention as defined in any one of claims 1 to 10, in a treatment site in the treated subject to which tissue elongation is required, by means of anchoring wires or screws; attaching one end of one or more pulling wires to said soft tissue, attaching another end of said pulling wires to the rotatable or telescopic axially movable member (s) of said implantable device, applying magnetic field signals by means of an external magnetic source placed near or around a portion of the body of the treated subject comprising said implantable device thereby causing said one or more pulling wires to retract due to movements of said rotatable or telescopic axially movable member (s) and stretch said soft tissue, repeating the application of said magnetic field signal until said soft tissue elongated to a desirable length.

12. The method according to claim 11, further comprising suturing said soft tissue to a connecting tissue or to a bone anchor.

13. The method according to claim 11, wherein the treatment site is a gap in the torn tissue.

14. The method according to claim 13, wherein the treatment site is a gap in the rectus abdominis muscle.

15. The method according to claim 11, wherein the implantable device is anchored in a cavity rimmed in a bone.

16. The method according to claims 11, wherein the implantable device is anchored externally to a bone.

17. The method according to claim 15 or 16, wherein the bone is the humerus medullary bone.