FIELD

The present invention relates to devices for arthroscopic surgery, such as for cartilage repair surgery, in particular to devices which allow delivering sensitive 3D materials to damage site.

BACKGROUND

Bone marrow stimulation techniques, such as microfracture, are considered the golden standard methods for the repair of cartilage defects. The focus has been put on developing three-dimensional (3D) scaffolds that have a highly porous structure and an interconnected pore network that supports chondrogenesis and regeneration of cartilage tissue. Compliance with mechanical properties is also required to withstand the various loads to which the forming repair tissue is subjected.

Varied instrumentation is required throughout the surgery for implanting 3D scaffolds. Due to the delicate nature of the implantation procedure, the method by which the transplanted graft is handled and introduced into the recipient site is of particular importance.

A desirable delivery device would provide a means for securely holding onto the 3D scaffold so that it is not displaced from the delivery device prematurely while simultaneously avoiding damage to the scaffold. An exemplary device suitable for 3D scaffold transportation is shown in figure 1. The device 100 comprises an elongated member 101 comprising a tube 102, a plunger 103 adapted to move in the tube, and a shaft 104 for receiving the scaffold. When desired, the scaffold is extruded from the shaft through an opening 105 by depressing the plunger in (-) x-direction of the coordinate system 199 until further distal movement of the plunger is limited by the plunger handle 106. Design of the shaft is such that the material holds its position until pushed through the opening by using external force.

Although the prior art devices, such as the one shown in figure 1 , are suitable for delivering of various 3D grafts and scaffolds, delivering of hydrophilic 3D scaffolds, e.g. porous structures comprising collagen, such as those disclosed in WO2016/042211A1 , is more challenging, since they should be delivered to the damage site as dry as possible. If the material hydrates before reaching the damage site, it is prone to adhere elsewhere than on the destination site. Furthermore, the material may be loaded by fluids not carrying the cells capable for cartilage regeneration, such as fluids used in the arthroscopic procedure. In addition, the porous dry materials are prone to dissemble if extruded from implantation devices using external force. Accordingly, there is still need for further delivery devices.

SUMMARY

The following presents a simplified summary in order to provide a basic understanding of some aspects of various embodiments of the invention. The summary is not an extensive overview of the invention. It is neither intended to identify key or critical elements of the invention nor to delineate the scope of the invention. The following summary merely presents some concepts of the invention in a simplified form as a prelude to a more detailed description of exemplifying embodiments of the invention. In the present invention it was observed that implantation of delicate hydrophilic 3D scaffolds can be performed by using a device comprising a chamber for receiving the 3D scaffold, wherein the chamber is sealed until the 3D scaffold is transferred to the damage site.

Accordingly, the present invention concerns a device for delivering 3D scaffold to a tissue damage site, the device comprising an elongated member and a chamber comprising an opening for receiving a 3D scaffold at the distal end of the device. The chamber comprises a shutter adapted to seal the opening, and a mechanism for operating the shutter.

Various exemplifying and non-limiting embodiments of the invention are described in accompanied dependent claims.

Various exemplifying and non-limiting embodiments of the invention both as to constructions and to methods of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific exemplifying embodiments when read in conjunction with the accompanying drawings.

The verbs“to comprise” and“to include” are used in this document as open limitations that neither exclude nor require the existence of also un-recited features. The features recited in dependent claims are mutually freely combinable unless otherwise explicitly stated. Furthermore, it is to be understood that the use of“a” or“an”, i.e. a singular form, throughout this document does not exclude a plurality.

BRIEF DESCRIPTION OF THE DRAWINGS

The exemplifying and non-limiting embodiments of the invention and their advantages are explained in greater detail below with reference to the accompanying drawings, in which: figure 1 shows cross-section of an exemplary device for delivering 3D scaffold into damage site according to prior art,

figure 2 shows a cross section of a device according to an exemplary and non-limiting embodiment of the invention, wherein the retracting means is in the first arrangement (a) and in the second arrangement (b),

figure 3 shows isometric views of a distal end of a device according to an exemplary and non-limiting embodiment of the invention, wherein the shutter is in open arrangement (a), in half open arrangement (b) and in closed arrangement (c), and

figure 4 shows a flow chart of an exemplary non-limiting method of use of the device according to the invention.

DESCRIPTION

The specific examples provided in the description given below should not be construed as limiting the scope and/or the applicability of the appended claims. Lists and groups of examples provided in the description given below are not exhaustive unless otherwise explicitly stated.

Figure 1 has been discussed in the Background section of this document.

Figure 2 illustrates a device 200 according to an exemplifying and non-limiting embodiment of the invention for delivering delicate hydrophilic 3D materials to targets such as cartilage lesions in synovial joints. Figure 3 illustrates isometric views of distal end of the device shown in figure 2.

As used herein, "a three-dimensional material" refers to any material construct that has height, width and depth. One example of a three-dimensional material is a 3D scaffold.

The device 200 comprises an elongated member 201 and a chamber 202 at distal end 200a of the device for receiving a 3D scaffold 203. The chamber comprises an opening 204, a shutter 205 adapted to seal the opening, and a mechanism 206 for operating the shutter. In figure 2, the shutter is open. The shutter and its movement are best seen in figure 3, wherein the shutter is in open (a), half closed (b) and closed (c) arrangement. A particular shutter is a sliding door.

According to a preferable embodiment the mechanism 206 comprises a user interface 207 connected to the shutter via a rotatable elongated member 208. According to a particular embodiment, the user interface is a knob or a nut 207 at proximal end 200b of the device, preferably as a part of the handle 209. According to an exemplary embodiment the rotatable elongated member, such as a shutter rotating axle, is connected to the shutter by a weldment. According to one embodiment, movement of the shutter is controlled by the operator of the device by rotating the knob. Rotation of the knob is demonstrated in figure 2 (a) by an arrow 210. According to another embodiment the device comprises an electric motor for operating the shutter, preferably via the rotatable elongated member.

According to a preferable embodiment the device comprises retracting means 211. The retracting means comprises a portion adapted to expand against sub-surface tissues when the device is in use. The retracting means makes the device particularly suitable for arthroscopic surgery since no further devices for providing working space for a surgeon is required.

The retracting means is adapted to move between the first arrangement 211 a i.e. a closed configuration and the second arrangement 211 b, i.e. an open configuration. When the retracting means is in the second arrangement, it dimensions in (±)-y- and (±)-z-direction of the coordinate system 299 is enlarged relative to the first arrangement. In figure 2, the retracting means is shown in the first arrangement 211 a and in the second arrangement 211 b.

When the retracting means is placed in the second arrangement 211 b between the articular surface and the synovial capsule it is ensured that the synovial capsule does not collapse should the pressure obtained by irrigation drop. Furthermore, the device is removable after the operation without significantly damaging the moved or retracted tissue such as synovium, by converting the retracting means to the first arrangement 211 a.

According to a preferable embodiment the retracting means comprises an elastic member 212, an energy storing means 213 and a non-elastic member, i.e. a plunger 214 between the elastic member and the energy storing means. According to a preferable embodiment the energy storing means is a spring, preferably positioned in the handle. The energy storing means is shown in figure 2 in compressed 213a (figure 2a) and relaxed 213b (figure 2b) arrangement.

According to a preferable embodiment the plunger is adapted to slide on the outer surface of the elongated member 201. According to an exemplary embodiment the elastic member is attached on the outer surface of the distal end of the elongated member and on the outer surface of the distal end of the plunger so that its movement in (indirection of the coordinate system is restricted and controlled by the elongated member and the plunger, respectively. According to an exemplary embodiment the elongated member and the plunger have grooves 215a,b for receiving the non-elastic member. When the elastic member has been assembled into the grooves, it holds its position during operation of the device.

The plunger has preferably a user interface 216 such as a plunger handle for operating the retracting means. The plunger handle acts also as a controlling means by avoiding the device to be pushed too deeply towards the lesion site when the retracting means is at its first arrangement. An exemplary plunger is an elongated hollow tube made of non-elastic material such as metal surrounding the elongated member 201.

As defined herein elastic member is an object which returns to its original shape and size after forces deforming it have been removed. The elastic member can be made of any elastic material suitable for surgical use. Particular material for the elastic member is silicone.

Operation of the retracting means is demonstrated in figure 2 with the double headed arrow 217. When an operator pulls the plunger handle 216 in (+)-x-direction of the coordinating system 299, movement of the plunger stretches the elastic member attached to the plunger in (+)-x-direction of the coordinating system 299 so that it is forced from the relaxed arrangement 212b to the stretched arrangement 212a. Simultaneously, the plunger is pushed towards the energy storing means which is transformed from the relaxed arrangement 213b to the compressed arrangement 213a. When the operator releases the plunger handle 216, the force generated by the energy storing means 213 pushes the plunger, and thus also the elastic member in (-)-x-direction of the coordinating system 299. Accordingly, the elastic member returns to its original shape, i.e. to relaxed arrangement 212b, and thus the retracting means is moved from the first arrangement 211 a to the second arrangement 211 b.

According to another embodiment the device comprises an electric motor for operating the retracting means.

According to one embodiment the device further comprises gas delivering means 218 adapted to allow flow of dry gas such as CO2 towards the distal end of the device. According to an exemplary nonlimiting embodiment the gas delivering means comprises a gas inlet port 219 at the proximal end, a gas outlet port 221 at the distal end, and a tubing 220 connecting the inlet port and the outlet port. The tubing is preferably a cavity in the elongated member. The device according to the present invention can be made of any material suitable for surgical use. A preferable material for non-elastic parts is metal, most preferably stainless steel. The elastic member can be made of any solid materials that return to their original shape after forces are applied on them. A preferable material is silicone. According to a preferable embodiment the design of the device allows the replacement of the elastic member after use.

An exemplary method for transporting a 3D scaffold to a damage site such as in cartilage repair surgery using a device of the invention is shown in figure 4. Accordingly, the method comprises the following actions:

Action 401 : providing a device comprising

o an elongated member and a chamber comprising an opening for receiving a 3D

material at a distal end, the chamber comprising a shutter to seal the opening, and o a retracting means adapted to move between a first arrangement and a second

arrangement.

Action 402: inserting a 3D scaffold in the chamber and closing the shutter.

Action 403: pushing, when the retracting means is in the first arrangement, the distal end of the device towards the damage site through an arthroscopic portal until the chamber is positioned in proximity to the damage site.

Action 404: moving the retracting means to the second arrangement.

Action 405: opening the shutter and removing the 3D scaffold from the chamber.

Action 406: moving the retracting means to the first arrangement.

Action 407: removing the device from the damage site by pulling through the arthroscopic portal.

According to a preferable embodiment, the shutter is closed before pulling the device through the arthroscopic portal, as an open shutter might be abrasive for tissues it goes against during removal. Furthermore, if the method is repeated, i.e. one or more pieces of 3D scaffolds are transported to the damage site during the same surgery, the chamber should be kept as dry as possible.

According to an exemplary embodiment the method further comprises irrigating the damage site with dry gas such as CO2 during the operation.

Exemplary devices for use in the method disclosed above are shown in figures 2 and 3. The specific examples provided in the description given above should not be construed as limiting the scope and/or the applicability of the appended claims. Lists and groups of examples provided in the description given above are not exhaustive unless otherwise explicitly stated.