Punch for partitioning a corneal graft and corresponding blade holder

Abstract

The invention relates to a punch for cutting a corneal graft (P), comprising a base (1) having a support surface (10) for a corneal tissue (C) and a blade holder (2) provided with at least one blade (20), the base (1) comprising a guide (12) for guiding the blade holder (2) in translation along a central axis (XI) normal to the support surface (10) between a first position in which the blade (20) is spaced apart from the support surface (10) and a second position in which the blade (20) is adjacent to the support surface (10), characterised in that the blade (20) is a blade for partitioning corneal tissue (C) extending substantially in a radial direction relative to the central axis (XI).

Description

[0001] PUNCH FOR PARTITIONED CUTTING OF A CORNEAL GRAFT AND CORRESPONDING BLADE HOLDER

[0002] The present invention relates to the field of corneal transplantation, in particular the field of graft preparation in the context of corneal surgeries (or keratoplasties), in particular the preparation of grafts for the implementation of the endothelial corneal transplantation technique with a Descemet membrane graft, otherwise known as the DMEK technique (Descemet Membrane Endothelial Keratoplasty).

[0003] BACKGROUND OF THE INVENTION

[0004] The cornea is the transparent front part of the eye. Its main function is to protect the inside of the eye from shocks and external aggressions and constitutes the first refractive element of the eye. The cornea is made up of several transparent tissue layers, thus allowing light to be transmitted to the lens and the retina.

[0005] Following an external attack (shock, burn, etc.) or pathological or age-related degeneration, the cornea can thicken and become opaque, even causing blindness. To remedy this, it is possible to perform a transplant of all or part of the cornea.

[0006] Several grafting techniques exist. They are distinguished by the nature and tissue composition of the graft taken. Thus, the PK technique (Penetrating keratoplasty) uses a graft taken from the entire thickness of the donor cornea (epithelium; Bowman's membrane; stroma; Dua's layer; Descemet's membrane; endothelium). The DALK technique (Deep Anterior Lamellar Keratoplasty) uses a graft made up of the anterior and middle layers (epithelium; Bowman's membrane; stroma; Dua's layer). The more recent techniques, DSAEK and DMEK, use grafts made up of the Descemet membrane and endothelium, or only the Descemet membrane, respectively.

[0007] These last two techniques (DSAEK and DMEK) are currently preferred because they do not require trepanation of the recipient eye, thus allowing a faster recovery of the patient.

[0008] Regardless of the techniques used, grafts are taken from the corneas of deceased subjects, and these corneas are stored in graft banks. Although there is no incompatibility between the donor and the recipient, the number of grafts available is always insufficient.

[0009] Indeed, not only is the number of donors insufficient, but the techniques of tissue harvesting and then preparing the graft for the recipient are carried out manually and are very delicate, even for experienced people. The harvesting of the donor tissue including the cornea, its preparation for the graft as well as the graft itself, are all steps likely to damage the graft, making it unusable, which also contributes to the graft shortage.

[0010] Thus, securing and assisting in carrying out these steps is the subject of a number of research and developments in tools and devices for harvesting and preparing grafts.

[0011] These include tools to aid in cutting and preparing the graft.

[0012] In particular, there are cutting devices on the market commonly called “punch” devices.

[0013] A punch comprises, on the one hand, a circular base in the center of which the donor corneal tissue is held by an automatic or manual suction system (for example, a syringe) connected to the base and, on the other hand, a blade holder which fits around the base thus allowing the operator (surgeon or graft bank technician) to cleanly cut the piece of cornea in a circular manner to the desired diameter according to the morphology and indications of the patient to be grafted.

[0014] As examples, it is possible to refer to the following documents: US-A-2021121328 which describes a circular blade having a U-shaped appendage; FR-A- 2992849 which describes a blade in the shape of an arc; and US2020 / 0121505 which describes a system for guiding the blade support with respect to the base to optimize cutting. However, these devices have several drawbacks. Thus, even if these devices make it possible to secure the preparation of the graft to a certain extent, a single donor tissue sample only allows one potential graft to be obtained. In other words, a cornea taken from a donor only allows one graft to be obtained.

[0015] Furthermore, even if the cutting of the graft is guided by these devices, they do not facilitate its handling after cutting. In particular, when it comes to making Descemet membrane grafts for DSAEK or DMEK surgeries, the Descemet membrane, which is both very thin and very elastic, will tend to roll up on itself, making it difficult to place the graft in the patient to be grafted. It is then necessary to unroll the graft before grafting, without tearing it.

[0016] SUBJECT OF THE INVENTION

[0017] The invention aims in particular to at least partially overcome the aforementioned drawbacks by proposing a punch making it easier to obtain corneal grafts.

[0018] SUMMARY OF THE INVENTION For this purpose, a corneal graft cutting punch is provided having a corneal tissue support surface and a blade holder provided with at least one blade. The base comprises a guide for guiding the blade holder in translation along a central axis normal to the support surface between a first position in which the blade is spaced from the support surface and a second position in which the blade is adjacent to the support surface.

[0019] According to the invention, the blade is a corneal tissue partition blade extending substantially in a direction radial to the central axis.

[0020] From the same donor corneal tissue, it is therefore possible to obtain at least two grafts, thereby increasing the number of grafts that can be performed from the same corneal tissue.

[0021] Preferably, the partition blade has an S-shaped section along a plane perpendicular to the central axis.

[0022] According to a preferred embodiment of the invention, the partition blade extends on either side of the central axis to divide the corneal tissue into two parts.

[0023] Preferably, the slide is arranged such that the two pieces of corneal tissue obtained from the donor corneal tissue are not mirror images of each other.

[0024] Preferably, the blade is arranged in such a way that the two pieces of corneal tissue obtained have a portion with an acute angle which facilitates gripping.

[0025] According to an alternative embodiment of the invention, the blade holder is provided with at least three partition blades thus defining two by two an angular sector.

[0026] Thus, the punch according to the invention makes it possible to obtain from a single corneal tissue taken from a donor and placed on the support surface of the base of the punch, by fitting with the blade holder, at least two pieces of corneal tissue comprising at least one end forming an angular sector (in the shape of a point and better in an acute angle). Not only does the punch according to the invention make it possible to obtain several pieces of corneal tissue from a single sample of donor tissue but also to facilitate its handling. Indeed, when the cut piece of corneal tissue of Descemet membrane is rolled up, the presence of an end in an angular sector (in the shape of a point and better in an acute angle) facilitates its unrolling by the operator (surgeon or preparer).

[0027] The blade holder may further be provided with a circular peripheral blade centered on the central axis. Preferably, the peripheral blade and the partition blade have heights such that the peripheral blade and the partition blade penetrate the corneal tissue to a depth at least equal to a thickness of the Descemet membrane.

[0028] Optionally, at least one of the blades in the blade holder is removable.

[0029] The guide preferably comprises two complementary guide surfaces, parallel to the central axis, cooperating with each other and one belonging to the base and the other to the blade holder. The blade holder and the base are advantageously arranged to fit into each other. The punch according to the invention may further comprise indexing means comprising a positioning index secured to one of the base and the blade holder to be placed in a notch provided in the other of the base and the blade holder during fitting.

[0030] The present invention also relates to the blade holder provided with at least one punch partition blade as previously described. Other characteristics and advantages of the invention will emerge from reading the following description of particular and non-limiting embodiments of the invention.

[0031] BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Reference will be made to the attached drawings, including:

[0033] [Fig. 1]: schematic view in axial section of a punch conforming to a first embodiment of the invention;

[0034] [Fig. 2]: enlarged schematic view according to frame II of figure 1.

[0035] [Fig. 3]: schematic axial sectional view of a blade holder according to a first embodiment of the invention; [Fig. 4]: schematic view from below, slightly in perspective, of a blade holder according to a first embodiment of the invention, showing the interior of said blade holder;

[0036] [Fig. 5]: schematic top view, slightly in perspective, of a punch base conforming to a first embodiment of the invention;

[0037] [Fig. 6]: schematic view from below, slightly in perspective, of a blade holder according to a variant of the invention, showing the interior of said blade holder.

[0038] [Fig. 7]: schematic view in axial section of a punch conforming to a second embodiment of the invention;

[0039] [Fig. 8]: enlarged schematic view according to frame VIII of the figure.

[0040] [Fig. 9]: schematic axial sectional view of a blade holder according to a second embodiment of the invention; [Fig. 10]: schematic view from below, slightly in perspective, of a blade holder according to a second embodiment of the invention, showing the interior of said blade holder;

[0041] [Fig.11]: schematic top view, slightly in perspective, of a punch base conforming to a second embodiment of the invention;

[0042] [Fig.12]: schematic view in axial section of a punch according to a first variant of a second embodiment of the invention;

[0043] [Fig.13]: schematic view in slight perspective of a blade holder according to a second variant of a second embodiment of the invention;

[0044] [Fig. 14]: schematic view in axial section of a punch conforming to a third embodiment of the invention;

[0045] [Fig. 15]: enlarged schematic view according to frame XV of figure 14;

[0046] [Fig. 16]: schematic view in axial section of a punch conforming to a fourth embodiment of the invention;

[0047] [Fig. 17]: enlarged schematic view according to frame XVII of figure 16;

[0048] [Fig.18]: schematic view in axial section of a punch according to a variant of a fourth embodiment of the invention;

[0049] [Fig. 19]: enlarged schematic view according to frame XVII of figure 18

[0050] [Fig. 20]: schematic view slightly in perspective of a corneal tissue after cutting by a punch according to the first mode or the third mode of embodiment of the invention in which the piece of cornea C2 has already been removed and the piece of cornea Cl cut remains to be removed from the corneal tissue C;

[0051] [Fig. 21]: schematic view slightly in perspective of a corneal tissue after cutting by a punch according to the second mode or the fourth mode of embodiment of the invention in which the piece of cornea C2 has already been removed and the piece of cornea Cl cut remains to be removed from the corneal tissue C.

[0052] DETAILED DESCRIPTION OF THE INVENTION

[0053] The present invention relates to a punch P for cutting grafts from corneal tissue C, comprising a base 1 and a blade holder 2.

[0054] According to a first embodiment of the invention, illustrated by figures 1 to 5, the base 1 comprises a body 1.1 intended to rest on a work surface, on which is fitted a receptacle 13 delimiting with the body 1.1 a closed enclosure 11. Conventionally, the enclosure 11 is connected to a manual or automatic suction device 3. The receptacle 13 of the base 1 further comprises an external surface forming a support surface 10 in the form of a bowl which is intended to receive a corneal tissue C to be cut and which has a shape of revolution around a central axis XI. The corneal tissue C is taken from the donor's eye according to techniques known as such.The corneal tissue C has a dome shape of substantially circular section and comprises all the constituent cell layers of the cornea including the Descemet membrane in the context of DMEK surgery (but only a portion of said constituent cell layers of the cornea when it comes to DSAEK surgery). The support surface 10 thus has a slightly concave shape to accommodate the convex-shaped corneal tissue C from the donor, said support surface being delimited by a circular edge 10.1. Preferably, the support surface 10 is pierced with at least one orifice 16 in communication with the closed enclosure 11 so that when the suction device 3 is actuated, a depression is generated at the level of the support surface 10 to press and hold in place the corneal tissue C against the support surface 10.The support surface 10 generally has a diameter greater than the usual diameter of the corneal tissue C, i.e. generally greater than 10 mm.

[0055] The blade holder 2, illustrated more particularly by figures 1, 2, 3 and 4, comprises a cover 21 which is arranged to cover the receptacle 13 of the base 1 and which comprises a sleeve 22 having a central axis X2 and an end partially closed by a bottom 23, said bottom 23 defining the plane A, substantially perpendicular to the axis X2. The bottom 23 is perforated with openings 26 to allow the practitioner to see inside the cover 21 when cutting the corneal tissue C. The cover further comprises a central stud 24 which projects from the bottom 23 inside the sleeve 22. The central stud 24 here has a surface of slightly convex shape defined so as to fit into the slightly concave shape of the surface of the support 10 of the base 1. The central stud 24 is provided with at least one blade 20 which extends substantially in a radial direction relative to the central axis X2 to have a partition function.More precisely, the blade 20 has a mean plane extending parallel to the central axis X2 and radially relative to it. Thus, the blade 20 is intended to divide the corneal tissue C which rests on the support surface 10, into at least two pieces of cornea C1, C2, in a direction substantially radial relative to the central axis X2. Each of the two pieces of cornea C1, C2 respectively forms a graft. The blade 20 is fixed in the central stud 24 of the blade holder 2 such that the cutting edge 20.1 of the blade extends in axial projection from the central stud 24 and in a direction radial relative to the central axis X2 to define a plane B substantially parallel to the plane A and therefore perpendicular to the axis x2.The blade 20 can be fixed to the central stud 24 by any means known as such to those skilled in the art, this can be, by way of non-limiting examples, a fixing by: clamping or pinching on either side of the blade, by screwing, by overmolding, by gluing, etc. The fixing of the blade can be carried out permanently or the blade can be removable to facilitate its changing and / or cleaning. The blade 20 here has an S-shaped section along a plane perpendicular to the central axis X2 and preferably extends on either side of the central axis X2 to divide the corneal tissue C into two parts to form two pieces of cornea C1, C2 comprising at least one end forming an angular sector (in the shape of a point and better in an acute angle). A person skilled in the art will be able to define the length of blade 20 as a function of the diameter of the corneal tissue to be cut and the radii of curvature of the S of the blade such that the blade 20 divides the corneal tissue C in two.

[0056] According to this first embodiment of the invention, the cutting edge 20.1 of the blade 20 extends in a plane B substantially parallel to the plane A, defined by the bottom 23, as is particularly illustrated by FIG. 3. The height of the blade 20 projecting from the stud 24 is defined such that when the blade holder 2 and the base 1 are assembled, the cutting edge 20.1 of the blade 20 penetrates into the corneal tissue C to a depth at least equal to a thickness of the Descemet membrane, i.e. a depth at least equal to 0.35 mm. The person skilled in the art will be able to determine the height of the blade 20 projecting from the stud 24, depending on the shape of the stud 24, in particular its convexity, such that on the one hand the cutting edge 20.1 of the blade 20 is located in a plane B parallel to the plane A and that the cutting edge 20.1 penetrates into the corneal tissue C to a depth at least equal to the Descemet membrane. Here, and by way of illustration, the central part 20.c of the blade projects from the convex surface of the stud 24 by a height hl of 0.35 mm while the ends 20a and 20b of the blade project from the stud 24 by a height h2 of at least 1.1 mm, here hl is therefore different from h2.

[0057] According to this first embodiment, clearances 15a; 15b may be provided in the receptacle 13 and / or the support surface 10 of the base 1 opposite the cutting edge 20.1 of the blade 20 to accommodate a portion of each of the ends 20.1a; 20.1b of the partition blade 20 so that the central part of the blade 20.1c comes into contact with the corneal tissue C placed on the concave support 10 of the base 1 to cut it into two pieces C1 and C2 with a thickness at least equal to the Descemet membrane. To cut the corneal tissue C into two pieces C1 and C2, the blade holder 2 is assembled to the base 1 using a guide 12. The guide 12 is arranged to relatively guide the blade holder 2 in translation along a central axis X1, X2 normal to the support surface 10 between a first position in which the blade 20 of the blade holder 2 is spaced from the support surface 10 and a second position in which the blade 20 is close to the support surface 10.The guide 12 comprises two complementary surfaces parallel to the central axis XI, X2, one 12a belonging to the base 1 and the other 12b to the blade holder 2. The guide 12 is here formed by the external surface 12a of the receptacle 13 and the internal surface 12b of the sleeve 22 of the blade holder 2. Here, the receptacle 13, of cylindrical shape, has a circular section with a diameter slightly smaller than the internal diameter of the sleeve 22 of the blade holder 2.

[0058] Here, the punch P further comprises angular indexing means 14 for indexing the blade holder 2 relative to the base 1 around the central axis XI, X2 (merged during fitting). The indexing means comprise a positioning index secured to one of the base 1 and the blade holder 2 to be placed in a notch provided in the other of the base 1 and the blade holder 2 during fitting. Here, the positioning index 14b is secured to the blade holder 2. It is a raised element (such as a rib or a lug) projecting from the internal surface of the sleeve 22 of the blade holder 2. This raised element engages in a notch 14a of the receptacle 13 of the base 1.The person skilled in the art will know how to position the index 14b and the notch 14a so that the ends 20a, 20b of the partition blade 20 come perfectly opposite the clearances 15a, 15b of the base 1 during the assembly of the blade holder 2 with the base 1, thus allowing a clean cutting of the two pieces C1, C2 from the corneal tissue C while preventing a relative rotational movement of the base 1 and the blade holder 2 during the assembly. Thus, when the blade holder 2 is engaged on the receptacle 13, the cutting edge 20. 1a and 20. 1b of the ends 20. a, 20. b of the partition blade come to bear on the bottom of the clearances 15. a and 15. b and the cutting edge 20. 1c of the central portion 20c of the partition blade 20 cuts the corneal tissue C into two pieces Cl and C2 over a height at least equal to the thickness of the Descemet membrane.

[0059] The two pieces of corneal tissue C1, C2 thus obtained are inscribed in the circle formed by the initially removed corneal tissue C and in a pictorial manner, the two pieces of corneal tissue C1 and C2 substantially reproduce the two complementary forms of the known symbol of "yin" and "yang". It is noted that the S-shaped blade 20 cuts the corneal tissue in such a way that each piece C1, C2 obtained after partition has a point defining an acute angle and at the opposite end a wider zone with a more or less hemicircular shape. It is also noted that according to this first embodiment in which the cutting edge 20.1 of the blade 20 defines a plane B, the piece of cornea C1, C2 obtained has a point and an opposite end (of more or less circular shape) thicker than the center of said piece of cornea since the cut is deeper at the periphery than at the center as illustrated by figure 20.

[0060] According to a variant of the first embodiment of the invention, as illustrated by Figure 6, the blade holder 2 comprises at least three partition blades defining two by two an angular sector. In a manner similar to the first embodiment, the person skilled in the art will know how to provide clearances in the base 1 opposite the ends of each of the blades so that when the blade holder 2 is assembled on the base 1, the ends of the blades come to bear against the clearances and the central part of the blades cuts the corneal tissue placed on the support to a thickness at least equal to the Descemet membrane. In the same way, the person skilled in the art will position the angular indexing means so that the ends of each of the blades are perfectly opposite the clearances provided in the base 1.

[0061] It is specified that elements identical or analogous to those previously described will bear the same numerical reference as the latter in the following description of the other embodiments of the invention.

[0062] According to a second embodiment of the invention, illustrated by figures 7 to 10, the punch P comprises a base 1 and a blade holder 2. Here, the blade holder 2, particularly illustrated by figures 9 and 10, differs from the blade holder described in the first embodiment of the invention in that the cutting edge 20.1 of the blade 20 projects from the surface of the stud 24 over the same height hl, h2 so that the cutting edge 20.1 of the blade 20 matches the concave shape of the support surface 10. It will be noted that here, unlike the first embodiment of the invention, the cutting edge 20.1 of the blade does not define a plane B parallel to the plane A, the height hl being identical to the height h2. The height hl, h2 is defined such that when assembling the blade holder 2 with the base 1, the cutting edge of the blade 20.1 cuts the corneal tissue C into two pieces C1 and C2 with a thickness at least equal to the Descemet membrane, the two pieces C1 and C2 being inscribed in the circle formed by the corneal tissue C initially removed and substantially reproducing the two complementary forms of the known symbol of “yin” and “yang”. Here, the heights hl, h2, are equal. As an illustration, the blade 20.1 is shown as being transfixing (hl, h2 being equal to at least 0.8mm) in figure 8.

[0063] According to this second embodiment, the base 1 differs from the base 1 described in the first embodiment in that it does not include any clearances or indexing means. Indeed, the latter are unnecessary since the cutting edge of the blade 20 has a shape complementary to the support surface 10. According to this second embodiment, the cut of the corneal tissue C is at least equal to the Descemet membrane. As illustrated by figure 21, the pieces of cornea C1, C2 obtained therefore have here a point and an opposite end (of more or less circular shape) of the same thickness as their center since the cut is of the same depth.

[0064] According to a first variant of the second embodiment of the invention, illustrated by Figure 12, the blade holder 2 further comprises stop means 27, also called guard. The stop means 27 are defined such that when assembling the blade holder 2 with the base 1, the stop means come into contact with the periphery of the corneal tissue C placed on the support surface 10 of the base 1, thus limiting the height of the cut of the corneal tissue C by the cutting edge 20.1 of the partition blade 20 to a thickness at least equal to the Descemet membrane. Here, and by way of illustration, the stop means 27 are arranged around the central stud 24. This is a thickening of the stud 24 but these stop means could also be obtained by adding a cylindrical wall around the stud 24 which would come into abutment on the surface 10.1 of the receptacle 13. Those skilled in the art will know how to produce the stop means as they see fit.

[0065] It is specified that the base 1 is identical to that described in the second embodiment of the invention and does not include any clearances. It may be provided that these stop means are adjustable to allow adjustment of the cutting height. The stop means may for example comprise a nut / lock nut assembly engaged by screwing onto the blade holder 2 or the base 1.

[0066] According to a second variant of the second embodiment of the invention, illustrated by Figure 13, the blade holder 2 comprises at least three blades defining two by two an angular sector. Here, in a manner similar to the second embodiment of the invention, the cutting edge 20.1 of the blades protrudes from the stud 24 over the same height (hl is equal to h2), the cutting edge of the blades thus matching the shape of the support surface 10. It is specified that the blade holder 2 may or may not comprise stop means 27.

[0067] According to a third embodiment of the invention, illustrated by figures 14 and 15, the punch P comprises a base 1 and a blade holder 2.

[0068] The blade holder 2 differs from the blade holder 2 described in the first embodiment of the invention in that it comprises, in addition to the partition blade 20, a peripheral blade 25 fixed in the central stud 24. The blade holder 2 according to this third embodiment of the invention therefore makes it possible to make two simultaneous cuts of the corneal tissue C: a circular cut and a cut into two pieces C1 and C2.

[0069] It is recalled that the cutting edge 20.1 of the partition blade 20 defines a plane B parallel to the plane A formed by the bottom 23. The peripheral blade 25, of circular section, is centered on the central axis X2 and surrounds the partition blade 20. The diameter of the peripheral blade 25 is defined as a function of the desired final dimensions of the pieces of corneal tissue C. Those skilled in the art will be able to determine these dimensions as a function of the patient to be grafted. The diameter of the peripheral blade 25 is conventionally between 6 mm and 10 mm. It is possible to provide several blade holders with peripheral blades 25 whose diameter varies from 10 mm to 6 mm with a pitch of 0.25 mm. The cutting edge 25.1 of the peripheral blade 25 projecting from the surface of the stud 24 defines a plane C parallel to the plane A. We designate by h3 the height between the surface of the stud 24 and the cutting edge 25.1 of the peripheral blade.According to this third embodiment, the partition blade 20 is substantially inscribed in the peripheral blade 25.

[0070] According to this third embodiment, the heights of the cutting edge 20 . 1 of the partition blade 20 hl , h2 and the height h3 of the cutting edge 25 . 1 of the peripheral blade 25 are defined in such a way that:

[0071] - the peripheral blade 25 penetrates into the corneal tissue C to a depth at least equal to a thickness of the Descemet membrane. Preferably, the peripheral blade 25 makes it possible to make a transfixing circular cut of the corneal tissue C.

[0072] - the partition blade 20 penetrates into the corneal tissue C to a depth at least equal to a thickness of the Descemet membrane. By way of illustration, the partition blade 20 penetrates into the corneal tissue C to a depth at least equal to 0.35 mm.

[0073] Here, as in the first embodiment, the cutting edge 20.1 of the partition blade 20 defines a plane B parallel to the plane A and the cutting edge 25.1 of the peripheral blade 25 defines a plane C also parallel to the plane A (and therefore to the plane B). The planes B and C may or may not be the same.

[0074] As specified in the first embodiment, the partition blades 20 and / or peripheral blades 25 can be fixed to the blade holder 2 permanently or be removable to facilitate their changing and / or cleaning of the punch.

[0075] The base 1 according to the third embodiment of the invention is identical to that described in the first embodiment of the invention. Thus, the blade holder 2 and the base 1 are assembled by implementing a guide 12, the relative positioning of the blade holder 2 and the base 1 is carried out by the indexing means 14, the ends 20a, 20b of the partition blade 20 come to bear on the clearances 15a, 15b. The corneal tissue C is thus simultaneously cut circularly by the peripheral blade 25 and divided into two pieces C1, C2 by the partition blade 20 over a thickness at least equal to the Descemet membrane. The two pieces of corneal tissue C1, C2 thus obtained are inscribed in the circle cut by the peripheral blade 25 in the corneal tissue C initially removed. The pieces of corneal tissue Cl, C2 reproduce the two complementary forms of the known symbol of “yin” and “yang”.It is noted that the blade 20 is shaped in such a way that each piece of corneal tissue C1, C2 thus obtained has a point defining an acute angle and at the opposite end a wider zone with a more or less hemicircular shape thicker than the central part, since the cut is deeper at the periphery, as illustrated by figure 20. The pieces of corneal tissue C1, C2 obtained by this third embodiment have dimensions that can be directly used to be grafted onto the eye of a patient.

[0076] According to a fourth embodiment of the invention, illustrated by figures 16 to 19, the punch P comprises a blade holder 2 which differs from the blade holder described in the second embodiment of the invention in that it comprises, in addition to the partition blade 20, a peripheral blade 25 fixed in the central stud 24. For the record, the cutting edge 20.1 of the blade 20 projects from the surface of the stud 24 over the same height hl, h2 so that the cutting edge 20.1 matches the concave shape of the support surface 10 or in other words so that the cutting edge 20.1 of the blade follows the convex surface of the stud 24, hl being equal to h2. As previously described in the third embodiment, the peripheral blade 25, of circular section, is centered on the central axis X2 and surrounds the partition blade 20, its diameter is defined by a person skilled in the art according to the desired final dimensions of the pieces of corneal tissue C1, C2 to be grafted, conventionally between 6 mm and 10 mm.

[0077] The height h3 of the cutting edge 25.1 of the peripheral blade 25 is defined in such a way that it penetrates the corneal tissue C to a depth at least equal to a thickness of the Descemet membrane. Preferably, the peripheral blade 25 penetrates the corneal tissue C over the entire thickness so as to make a transfixing cut. The height of the cutting edge 20.1 of the partition blade 20 is determined in a manner identical to that described in the second embodiment of the invention so that the cutting edge 20.1 of the partition blade 20 penetrates the corneal tissue C to a depth at least equal to a thickness of the Descemet membrane. By way of illustration, the partition blade 20 penetrates the corneal tissue C to a depth at least equal to 0.35 mm. Here, h3 is greater than or equal to h1, h2

[0078] The base 1 according to the fourth embodiment of the invention is identical to that described in the second embodiment of the invention and does not include any clearances or indexing means. Thus, the blade holder 2 and the base 1 are assembled using a guide 12, until the peripheral blade 25 and the partition blade 20 cut the corneal tissue C into two pieces C1, C2 to a depth at least equal to the Descemet membrane. The two pieces C1 and C2 are inscribed in the circle cut by the peripheral blade 25 in the corneal tissue C initially removed and substantially reproduce the two complementary shapes of the known symbol of "yin" and "yang". It is noted that the blade 20 is shaped in such a way that each piece of corneal tissue C1, C2 thus obtained has a point defining an acute angle and at the opposite end a wider zone with a more or less hemicircular shape.The pieces of corneal tissue C1, C2 obtained by this fourth embodiment have a substantially constant thickness (since the cutting depth is substantially constant) as illustrated by Figure 21 and dimensions directly usable for being grafted onto the eye of a patient. According to a variant of the fourth embodiment of the invention similar to the first variant of the second embodiment, illustrated by Figures 18 and 19, the blade holder 2 further comprises stop means 27, also called a guard. The stop means 27 are defined such that when the blade holder 2 is assembled with the base 1, the stop means come into contact with the periphery of the piece of cornea, thus limiting the height of the cut of the corneal tissue C by the peripheral blade 25 and by the partition blade 20 to a thickness at least equal to the Descemet membrane. The base 1 is identical to that previously described.The assembly of the blade holder 2 with the base 1 is also identical, as is the shape of the pieces of corneal tissue C1, C2 thus obtained.

[0079] The examples below will provide a better understanding of how a person skilled in the art prepares a graft intended for a patient operated on using the DMEK technique.

[0080] Example 1: Use of a punch P according to the first or second embodiment of the invention to prepare a DMEK graft.

[0081] Step 1: Collection

[0082] Corneal tissue is removed from the donor eye and placed on the supporting surface 10 of the base 1. The suction system 3 is operated to “fix” the corneal tissue on the supporting surface 10. Step 2: Scoring

[0083] The operator cuts substantially circularly the corneal tissue C placed on the support surface 10 with a commercially available peripheral blade holder or manually with a hook to determine the cleavage plane for the delamination step.

[0084] Step 3: Delamination

[0085] Once the cleavage plane has been determined, the operator uses a spatula to delaminate the upper tissue layer of the corneal tissue corresponding to the Descemet membrane. This very thin layer (around 12 μm) nevertheless continues to adhere to the other cellular layers of the corneal tissue. Step 4: Circular trepanation

[0086] The operator then makes the circular cut of the delaminated corneal tissue with a blade holder with a peripheral blade of the final desired dimension depending on the patient. The cut is here with a diameter of less than 10 mm. The operator, depending on his practice, will use either a blade holder with a guarded blade to make a cut at a height equal to the thickness of the Descemet membrane at least, or a blade holder with a peripheral blade allowing a transfixing cut to be made.

[0087] Step 5: Trepanation of asymmetric partition.

[0088] The operator then assembles on the base 1, the blade holder 2 object of the invention comprising the partition blade 20 - as described in the first embodiment (cutting edge 20.1 of the blade defining a plane) or as described in the second embodiment (cutting edge 20.1 of the blade substantially matching the concave shape of the support surface) to cut the corneal tissue C into two pieces C1, C2.

[0089] The operator will choose base 1 respectively with or without clearance depending on the blade holder selected.

[0090] At the end of this step, the pieces C1, C2 of corneal tissue have the desired dimensions for grafting. They present the two complementary shapes of the known symbol of "yin" and "yang" inscribed in the circle cut by the peripheral blade.

[0091] Step 6: Removal of the pieces of corneal tissue Cl, C2 The operator uses an instrument to grasp the angular end of the first piece Cl of corneal tissue to place it in the preservation liquid or graft it directly onto the patient. Then, he will do the same with the second piece C2 of corneal tissue.

[0092] The Cl and C2 pieces thus obtained are perfectly suited to grafting using DMEK technology, while facilitating handling and limiting their number.

[0093] Example 2: Use of a punch P according to the third or fourth embodiment of the invention to prepare a DMEK graft

[0094] Steps 1 to 3 are the same as described in Example 1.

[0095] Step 4: Simultaneous circular and asymmetric partition trepanation.

[0096] The assembly of the blade holder 2 comprising a peripheral blade 25 and a partition blade 20 (cutting edge 20.1 of the blade defining a plane B) as described in the third embodiment or a peripheral blade 25 and a partition blade 20 (cutting edge 20.1 of the blade matching the concave shape of the support surface) as described in the fourth embodiment of the invention) makes it possible to obtain in a single operation and simultaneously two pieces of corneal tissue C1, C2 cut by the partition blade 20 having the two complementary shapes of the known symbol of “yin” and “yang” and inscribed in the circle cut by the peripheral blade 25 with a thickness at least equal to the Descemet membrane.

[0097] At the end of this step, the pieces Cl, C2 of corneal tissue have the desired dimensions for the graft. Step 5: Removal of the pieces of corneal tissue Cl, C2 This step is identical to step 6 described in the first example.

[0098] It is specified that the operator will use the base with or without clearance depending on the blade holder chosen.

[0099] Thus, the pieces of corneal tissue Cl and C2 have dimensions and thickness equal to the Descemet membrane which can be used directly to perform a graft using DMEK technology.

[0100] Thus, the use of a punch comprising a blade holder according to one of the embodiments of the invention described makes it possible to obtain from a single corneal tissue, several grafts by limiting the number of manipulations while making them easier. Indeed, not only is the corneal tissue C not displaced and is held on the support surface of the base throughout the cutting steps, but in addition the shape of the pieces of corneal tissue includes an end forming an acute angle which makes it possible to orient the graft, to facilitate its unwinding if necessary and to improve its positioning during the graft.In addition, the operator benefits from great flexibility of use to cut the grafts according to the quality of the corneal tissue, his practice and the planned surgery: use of one or more blade holders, with partition blade with a cutting edge in the same plane or with a cutting edge substantially matching the shape of the support or with peripheral blade and partition blade with a cutting edge in the same plane or with a cutting edge substantially matching the shape of the support with or without guard.

[0101] Of course, the invention is not limited to the embodiments described but encompasses any variant falling within the scope of the invention as defined by the claims.

[0102] In particular, the partition blade is here preformed in an S shape but it can be straight and elastically deformed with a punch after its placement in the central stud 24.

[0103] The partition blade can also have other shapes, notably a vertical plane shape.

[0104] The blade holder can be provided with several partition blades arranged in a star pattern as in Figure 6, the partition blades delimiting angular sectors in pairs.

[0105] The person skilled in the art is able to define the optimal length of the cutting edge 20. 1 of the blade 20 depending on whether the blade holder 2 comprises one or more partition blades 20 and a peripheral blade or not. Indeed, if the blade holder comprises a blade 20 extending on either side of the central axis X2 in a radial direction, the length of the cutting edge of the blade 20 will be substantially greater than the diameter of the piece of cornea placed on the support surface 10 of the base 1 and centered on the axis XI (thus, the length of the cutting edge of the blade 20 will vary substantially from 6 mm to substantially a little more than 10 mm). If the blade holder comprises at least three blades 20, the length of each of the blades 20 will be substantially greater than the radius of the piece of cornea placed on the support surface of the base and centered on the central axis XI. So the length of each blade will vary significantly from 3 mm to slightly more than 5 mm).

[0106] The stud 24 can be shaped so as not to come into contact with the corneal tissue C placed on the support surface 10 when the blade holder 2 is assembled on the base 1 or to come into abutment on the external periphery of the corneal tissue C to keep intact the part of the corneal tissue intended to be cut to form the two pieces of cornea C1 and C2.

[0107] The stud 24 here has a convex surface but it can also have a flat surface. The person skilled in the art will then know how to adapt the stop means and the height of the partition blade.

[0108] According to the first variant of the second or fourth embodiment of the invention, the blade holder comprises stop means 27 which come to bear on the periphery of the piece of cornea C but the stop means 27 can also be defined to come to bear on the circular edge 10. 1 of the support surface 10 of the base 1. The stop means can alternatively be provided on the base.

[0109] The base 1 and the blade holder 2 can be made of one or more easily sterilizable materials such as stainless steel or other stainless steels, or of plastic material having the same characteristics, in particular sterilization capacity.

[0110] The guide is here formed by the surfaces, respectively, external of the receptacle 12a of the receptacle 13 and internal 12b of the sleeve 22 of the blade holder 2 which come opposite each other during fitting, but the guide can also comprise guide columns secured to the base 1 and on which the blade holder 2 slides.

[0111] Blade holder 2 fits onto base 1 here, but the reverse is also possible.

[0112] The punch here has a more or less cylindrical shaped enclosure, the blade holder and the receptacle having a cylindrical shape, the body, the blade holder and the receptacle can take any other shape so that the blade holder and the base can be assembled.

[0113] The punch according to the invention makes it possible here to obtain at least two grafts from a piece of cornea C intended for DSAEK and DMEK type keratoplasties, but it is possible to define the height and shape of the partition blade 20 so as to obtain grafts intended for other surgeries of the DALK or even PK type.

Claims

CLAIMS 1. Punch for cutting a corneal graft (P), comprising a base (1) having a support surface (10) for a corneal tissue (C) and a blade holder (2) provided with at least one blade (20), the base (1) comprising a guide (12) for guiding the blade holder (2) in translation along a central axis (XI) normal to the support surface (10) between a first position in which the blade (20) is spaced from the support surface (10) and a second position in which the blade (20) is close to the support surface (10), characterized in that the blade (20) is a partition blade for the corneal tissue (C) extending substantially in a radial direction relative to the central axis (XI) and having an S-shaped section along a plane perpendicular to the central axis (XI).

2. Punch according to claim 1, wherein the partition blade (20) extends on either side of the central axis (XI) to divide the corneal tissue (C) into two parts (Cl, C2).

3. Punch according to any one of claims 1 and 2, in which the blade holder (2) is provided with at least three partition blades defining two by two an angular sector.

4. Punch according to any one of claims 1 to 3, the blade holder (2) being provided with a peripheral blade (25) centered on the central axis (XI).

5. Punch according to claim 4, wherein the blade peripheral (25) and the partition blade (20) have heights such that the peripheral blade (25) penetrates the corneal tissue (C) to a depth equal to a total thickness of said corneal tissue (C), the partition blade (20) penetrates the corneal tissue (C) to a depth at least equal to a thickness of Descemet membrane.

6. Punch according to claim 4 or 5, wherein at least one of the blades is removable.

7. Punch according to any one of the preceding claims, in which the guide (12) comprises two complementary guide surfaces (12a, 12b), parallel to the central axis, cooperating with each other and one belonging to the base (1) and the other to the blade holder (2).

8. Punch according to claim 7, wherein the blade holder (2) and the base (1) are arranged to fit into each other.

9. Punch according to claim 8, comprising angular indexing means (14) of the blade holder (2) relative to the base (1), the indexing means (14) comprising a positioning index secured (14a) to one of the base (1) and the blade holder (2) to fit into a notch (14b) provided in the other of the base (1) and the blade holder (2) when nesting.

10. Blade holder provided with at least one partition blade (20), for punch according to any one of the preceding claims.

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