GB2521360A

GB2521360A - Surgical device for storage and placement of grafts

Info

Publication number: GB2521360A
Application number: GB1322279.9A
Authority: GB
Inventors: Philip Douglas Weston
Original assignee: Individual
Current assignee: Individual
Priority date: 2013-12-17
Filing date: 2013-12-17
Publication date: 2015-06-24
Anticipated expiration: 2033-12-17
Also published as: GB201322279D0; GB2521360B

Abstract

The device is a cartridge 1 including an endothelial corneal implant 19 having a first, endothelial surface 24 and a second, opposed surface 23. The cartridge 1 comprises a generally tubular portion including a sidewall defining a longitudinal bore 4 of curvilinear cross section. The longitudinal bore 4 of the cartridge 1 includes a ridge element 5 extending longitudinally along at least a portion of the bore 4 and projecting inwardly thereinto from the sidewall. The implant 19 is held in a B-shaped configuration, the second surface 23 of the implant 19 facing the sidewall, with opposed edges of the implant 19 being curled inwardly by the ridge element 5 so as to rest gently on the endothelial surface 24 of the implant 19 at a location in the bore 4 opposite the ridge element 5. Opposed portions of the second surface 23 of the implant 19 contact each other in the bore 4 between the ridge element 5 and the aforementioned location.

Description

SURGICAL DEVICE FOR STORAGE AND PLACEMENT OF GRAFTS

[0001] Embodiments of this invention relate to a system and method for handling and inserting a corneal implant (also referred to as a donor cornea or lenticule) into the eye of a recipient without inducing significant endothelial damage.

BACKGROUND

[0002] A paradigm shift in the approach to corneal transplantation is occurring, with new forms of anterior and posterior lamellar keratoplasty now enabling targeted replacement of only diseased layers of the cornea. These forms of lamellar corneal surgery are gradually replacing conventional full thickness penetrating keratoplasty (Tan DT, Mehta JS: Future Directions in Lamellar Corneal Transplantation"; Cornea; October 2007; Volume 26; pp S21-S28).

[0003] Descemet's stripping automated endothelial keratoplasty (DSAEK) is a form of small incision and essentially sutureless surgery which represents the latest innovation in a series of posterior lamellar keratoplasty procedures that are now synonymous with the term "endothelial keratoplasty". The DSAEK procedure involves stripping of diseased Descemet's membrane and endothelial cells through a small corneal incision, and replacement with a posterior lamellar donor corneal lenticule prepared with the use of the Automated Lamellar Therapeutic Keratoplasty (ALTK) unit (Price MO, Price FW Jr.: "Descemet's stripping with endothelial keratoplasty: comparative outcomes with microkeratome-dissected and manually dissected donor tissue"; Ophthalmology; 2006 Nov; 113(11):1936-42).

[0004] With the adoption of any new surgical technique there is an inevitable learning curve for the surgeon and an accompanying evolution in techniques (see, for example: Price FW, Price MO: "DescemeVs stripping with endothelial keratoplasty in 200 eyes: Early challenges and techniques to enhance donor adherence"; J Cataract Refract Surg. 2006; 32(3):411-8; Melles GR, Lander F, Beekhuis WH, Remeijer L, Binder PS: "Posterior lamellar keratoplasty for a case of pseudophakic bullous keratopathy"; Am J Ophthalmol.

1999 Mar; 127(3):340-1; Melles GR, Lander F, Nieuwendaal C: "Sutureless, posterior lamellar keratoplasty: a case report of a modified technique"; Cornea; 2002 Apr; 21(3):325- 7; Melles GR, Wijdh RHJ, Nieuwendaal CP: "A technique to excise the Descemet membrane from a recipient cornea (descemetorhexis)"; Cornea; 2004 Apr; 23(3):286-8; Terry MA, Ousley PJ: "Replacing the endothelium without corneal surface incisions or sutures: the first United States clinical series using the deep lamellar endothelial keratoplasty procedure"; Ophthalmology; 2003 Apr; 110:755-64; discussion 764).

[00051 One of the most challenging aspects of this procedure is the insertion of the donor posterior lenticule into the anterior chamber (AC) through a small incision, without inducing significant endothelial damage. The current widely performed technique requires insertion of the donor lenticule through a small 5mm corneal or scleral incision by folding the lenticule and gripping the folded tissue with non-compressing forceps i.e. taco insertion'.

This traumatic handling of the donor has been criticized because of its propensity for damaging endothelial cells, with primary graft failure rates due to intraoperative endothelial cell loss and damage ranging from 6% to 45% in the current literature with this folding technique (Mearza AA, Qureshi MA, Rostron OK: "Experience and 12-month results of Descemet-stripping endothelial keratoplasty (DSEK) with a small-incision technique"; Cornea 2007 Apr; 26(3):279-283). Damage to endothelial cells may occur as a consequence of mechanical folding of the donor, compression with holding forceps, and may also occur during intraocular manipulations to unfold the donor within the AC without the presence of an ophthalmic visco-surgical device (OVD). More recently, laboratory models of DSAEK have shown that folding of the donor lenticule for insertion into the AC and intraocular manipulation to unfold the donor is the stage most associated with significant endothelial cell loss (Lee WB, Sy HM, Holley GP, Edelhauser HF: "Descemet's Stripping Automated Endothelial Keratoplasty (DSAEK): Intra-Operative Effects on the Donor Corneal Endothelium"; IOVS supplement; 2007; abstract 1131). The endothelial damage is worse in the presence of associated anterior chamber shallowing.

[0006] Our own extensive in-vitro work has confirmed that significant endothelial damage occurs with the conventional folding technique, despite the use of commercially available non-compression' forceps (Goosey forceps, model no. 19090, Mona, Antony, France).

Damage primarily occurring as a consequence of direct contact of folded endothelial surfaces where the folding forceps are applied, as well as along the folding crease (Mehta JS, Por YM, Beuerman RW, Tan DI: "Glide Insertion Technique of Donor Cornea Lenticule during Descemet's Stripping Automated Endothelial Keratoplasty"; J Cat Refract Surg; in press). Our recent studies show that the mean endothelial cell loss is 39% with this technique, which is now described: [0007] A 1mm paracentesis is first made in the peripheral cornea opposite a 5mm temporal scleral tunnel wound (for insertion of intraocular forceps). A standard, commercially available anterior chamber intraocular lens (IOL) Sheet's glide is trimmed to 4mm in width along approximately half to 2/3 of its length. Using Kelman Macpherson forceps, the glide is inserted into the AC through the scleral tunnel, with the right hand, whilst a balanced saline solution (BSS) infusion is maintained on. The donor (both the anterior and posterior lamellae) is transferred to a Paton's spatula. A dispersive OVD is liberally applied over the endothelial surface particularly the peripheral circumference of the donor. Carefully gripping the posterior donor lamellar with Kawai intraocular capsulorhexis forceps (Asico) on the stromal side, the anterior cap is slid away from the spatula, ensuring that the posterior donor lamella stays on the spatula. OVD is placed on the anterior surface of the glide, and the Paton spatula with the posterior lenticule is carefully everted, corneal endothelial surface down, onto the OVD-covered portion of the glide. Holding the glide with the right hand with Kelman Macpherson forceps at its most posterior part, the left hand, passes the Kawai forceps through the paracentesis, across the AC and over the sheets glide, and is passed out through the scleral incision. The Kawai forceps is rotated, so that the forceps teeth are now obliquely or vertically aligned, and can be used to grasp the leading edge of the donor lamella, on the upper stromal surface. Once the forceps grasped the donor edge, the donor is rapidly pulled through the scleral incision in one steady, smooth motion until the donor is fully in the AC. At the same time, the glide was retracted out of the eye.

[0008] We have performed this technique in 24 cases of DSAEK surgery, with only one primary graft failure occurring (4.2%). This contrasts with our previous 20 cases using the folding technique which had primary graft failure rate of 25% (5 eyes). Our scanning electron microscope (SEM) studies confirm that significant reduction in endothelial loss occurs with this technique, with a mean cell loss of 9%, mostly occurring at the peripheral rim, which may be due to contact of the donor edges with the plastic sheets glide, despite the use of OVD, and some damage must still occur when the donor is dragged through the lips of the wound, as the donor endothelial surface is still potentially in contact with the inferior lip of the scleral wound. We have not encountered any cases of donor dislocation with this technique, although we have now seen one case of partial Descemet's detachment. Our only primary graft failure occurred during our first case using this technique and can be attributed to the use of an excessively thick donor lenticule (400pm) which resulted in Descemet's detachment.

[0009] Recently, a new technique called Descemet's Membrane Endothelial Keratoplasty (DMEK) has been developed. In this endothelial keratoplasty technique, an isolated Descemet's membrane and endotheliurn layer is transplanted. This technique is even more difficult than DSAEK surgery, since an isolated Descemet's membrane is even thinner and more fragile than one which is supported by one or more layers of stromal cells.

[0010] A previous system and method developed by the present Applicants in order to facilitate DSEAK surgery is described in W02009/05051 1 and EP2491890, the full contents of each of which is hereby incorporated into the present application by reference.

This system for donor cornea implantation includes a preparation base having a well for receiving a donor cornea, a cartridge disengageably mounted on the base adjacent the well, and a handle for disengageable attachment to a posterior end portion of the cartridge.

In drawing the donor cornea from the well into and through a bore or chamber of the cartridge, from the posterior end, the donor cornea is caused to assume a double coil configuration by way of a longitudinal ridge on the interior of the cartridge. After attachment of the handle, removal of the assembly from the preparation base, and insertion of a blade and adjacent body portions of the cartridge through an incision in the recipient's cornea, the coiled donor cornea is pulled from the cartridge chamber, through its forward end, to uncoil automatically within the anterior chamber of the recipient's eye.

While effective, it is believed that there is still room for improvement.

[0011] It is explained, for example with reference to Figure 12 of EP2491890, that there is no contact between any endothelial areas of the implant.

[0012] Another system and method for performing corneal implant preparation and surgery is known from US2007/0244559, the full contents of which is hereby incorporated into the present application by reference. Here, a corneal implant is constrained within a deformation chamber that is hinged along its length and may be opened and closed by way of the hinge. The chamber includes a pair of protrusions that help to hold the edges of the implant when the chamber is open, and help to deform the implant into a double coil configuration when the chamber is closed.

[0013] It is emphasised in US2007/0244559 that the laterally opposed edges of the corneal implant remain everted but do not touch the interior surface of the corneal implant such that damage to the corneal implant is reduced.

[0014] More recently, there has been interest in performing surgery using even thinner endothelial grafts, for example Descemet's Membrane Endothelial Keratoplasty (DMEK).

In these techniques, the graft comprises just the Descemet's membrane with a layer of endothelial cells and no stromal cells on the other side of the Descemet's membrane. This has the advantage of reducing the likelihood of rejection due to an adverse immunological response to the foreign stromal cells. Ideally, it would be advantages to work with grafts comprising just a single layer of endothelial cells supported by the Descemet's membrane.

Such grafts may be as little as 11 or 12pm in thickness, and are extremely difficult to handle, having almost no inherent structural rigidity.

BRIEF SUMMARY OF THE DISCLOSURE

[0015] Embodiments of the invention may seek to provide an apparatus and method for inserting an endothelial corneal implant (which may be a donor implant harvested from a cadaver, or alternatively an artificial endothelial implant) into the eye of a recipient without inducing significant endothelial damage. The endothelial implant may comprise one or several layers of endothelial cells supported by a Descemet's membrane, optionally further supported by one or several layers of stromal cells. The endothelial implant may also be referred to as a donor cornea or lenticule.

[0016] Further embodiments of the invention may seek to provide such an apparatus and method wherein and whereby the donor cornea is temporarily deformed for effective insertion, while providing protection against significant endothelial damage.

[0017] Viewed from a first aspect, there is provided a cartridge including an endothelial corneal implant comprising a first, endothelial surface and a second, opposed surface, wherein the cartridge comprises a generally tubular portion including a sidewall defining a longitudinal bore of curvilinear cross section, wherein the longitudinal bore of the cartridge includes a ridge element extending longitudinally along at least a portion of the bore and projecting inwardly thereinto from the sidewall, wherein the implant is held in a B-shaped configuration, the second surface of the implant facing the sidewall, with opposed edges of the implant being curled inwardly by the ridge element so as to rest gently on the first, endothelial surface of the implant at a location in the bore opposite the ridge element, and with opposed portions of the second surface of the implant contacting each other in the bore between the ridge element and the said location.

[0018] Viewed from a second aspect, there is provided a cartridge for holding an endothelial corneal implant comprising a first, endothelial surface and a second, opposed surface, wherein the cartridge comprises a generally tubular portion including a sidewall defining a longitudinal bore of curvilinear cross section, wherein the longitudinal bore of the cartridge includes a ridge element extending longitudinally along at least a portion of the bore and projecting inwardly thereinto from the sidewall, wherein the ridge element is configured to hold the implant in a B-shaped configuration, the second surface of the implant facing the sidewall, with opposed edges of the implant being curled inwardly by the ridge element so as to rest gently on the first, endothelial surface of the implant at a location in the bore opposite the ridge element, and with opposed portions of the second surface of the implant contacting each other in the bore between the ridge element and the said location.

[0019] Viewed from a third aspect, there is provided a method of retaining an endothelial corneal implant in a cartridge, the cartridge comprising a generally tubular portion including a sidewall defining a longitudinal bore of curvilinear cross section, the longitudinal bore of the cartridge including a ridge element extending longitudinally along at least a portion of the bore and projecting inwardly thereinto from the sidewall, and the implant comprising a first, endothelial surface and a second, opposed surface, wherein the implant is inserted into the bore of the cartridge so as to assume a B'-shaped configuration, the second surface of the implant facing the sidewall, with opposed edges of the implant being curled inwardly by the ridge element so as to lest gently on the first, endothelial surface of the implant at a location in the bore opposite the ridge element, and with opposed portions of the second surface of the implant contacting each other in the bore between the ridge element and the said location.

[0020] The cartridge may have open forward and rearward ends to facilitate insertion and ejection of the implant into and out of the cartridge.

[0021] Insertion of the implant may be achieved using a preparation base (as described, for example, in W02009/05051 1 or EP2491890) and drawing the implant into the cartridge using a pair of forceps. Alternatively or in addition, the implant may be inserted into the longitudinal bore of the cartridge by way of a fluid flush, for example by applying a partial vacuum at an opposed end of the bore and causing a fluid to flow through the bore thereby to carry the implant into the bore. In this embodiment, the cartridge may comprise a continuous, fixed, one-piece sidewall with a fixed, one-piece ridge element. The ridge element may be integrally formed with the sidewall. In is to be noted that, in this embodiment, the cartridge does not have a hinge or hinged doors. The open ends of the cartridge may be provided with means for temporarily sealing the implant within the cartridge, for example in a nutrient or saline solution. The means may comprise caps or stoppers or the like, the same at each end of the cartridge or different.

[0022] Alternatively, the cartridge may be hinged along its length, for example as disclosed in US2007/0244559, or provided with doors to allow placement of the implant within the cartridge.

[0023] In order to eject the implant from the cartridge into the anterior chamber of a recipient's eye, the implant may be pulled out using a pair of forceps as described in W02009/050511 or EP2491890, or alternatively may be pushed out using a pusher member as described, for example, in W02009/05051 1 or US2007/0244559.

[0024] The pusher member may comprise an element, such as a linearly directed projection, for pushing the implant into place. The element may take the form of a piston which fits in the longitudinal bore, and which can be operated so as to push or eject the implant from the cartridge and into the eye of a recipient of the implant through a corneal incision. This embodiment is constructed in similar manner to a syringe. The element may alternatively take the form of a plate located at an end of a push-rod, the push-rod being connected to the plate at an edge thereof. This embodiment may be constructed in similar manner to a croupier's rake or croupier's tool.

[0025] Alternatively or in addition, the implant may be ejected from the cartridge into the recipient's eye by way of a fluid flush, for example by causing a fluid flow along the longitudinal bore of the cartridge by means of a syringe or the like. The cartridge may be provided with a fluid dispenser for causing a fluid flow along the bore so as to eject the implant from the bore and into an anterior chamber of a recipient's eye. The fluid may be a biocompatible liquid.

[0026] The cartridge may be adapted so that it is sealable, for example by way of a cap (e.g. screw fit or interference fit) or plug or stopper at one or both ends. In this way, a corneal implant can be prepared at a remote location, for example an eye bank, and stored the predetermined deformed shape in an appropriate nutrient solution or saline solution in a cartridge that is subsequently sealed. The sealed cartridge can then be shipped to a surgeon in ready-to-use form. The surgeon then need only remove the seal(s) from the cartridge before inserting the implant.

[0027] The cartridge may be made of transparent or translucent plastics materials. This may allow for clear visualisation of the donor at all times.

[0028] Surface tension and/or molecular adhesion effects may tend to promote attraction between the inner sidewall of the cartridge and the second surface of the implant. This can help to maintain the B-shaped configuration of the implant until it is ejected from the cartridge.

[0029] The cartridge may comprise attaching structure adjacent a rearward end of said tubular portion for disengageable attachment to a handle.

[0030] The system may further comprise a handle having a gripping portion and means adjacent one end for disengageable attachment to said disengageable attachment structure of said cartridge, said handle, when attached, enabling facile manipulation of said cartridge.

[0031] The attachment means of said handle may engage said attachment structure of said cartridge in only a single orientation of relative rotation about a longitudinal axis.

[0032] The attachment means of said handle engages attachment structure of said cartridge in a snap-fit relationship.

[0033] The handle may have closure structure at said one end thereof, constructed to engage said tubular portion of said cartridge and to thereby produce a liquid-tight seal of said normally open rearward end of said bore of said tubular portion.

[0034] The gripping portion of the handle may have opposite sides, and indicia may be provided on at least one of said opposite sides of said gripping portion to distinguish it from the other side thereof.

[0035] The ridge element of said cartridge may be configured to induce inward curling of opposite lateral edges of the implant as the implant is drawn into the bore of the cartridge and moved laterally along the bore for temporary storage therein.

[0036] The cartridge may have a blade portion extending forwardly from said sidewall beyond the forward end of said bore. The blade portion may be suitable for insertion into an incision in a corneal surface of a recipient eye.

[0037] The cartridge may advantageously be integrally formed, as a single piece, and will desirably be moulded from a substantially transparent or translucent synthetic resinous or plastics material. The ridge element may be formed with convexly curved lateral surfaces extending along its length and terminating in a common longitudinal apex. At the forward end of the tubular portion of the cartridge, the sidewall may be formed with a transaxial bevel that declines toward the blade portion, to facilitate physical access into the bore and insertion of the forwardmost part of the body portion into the recipient's eye. The curvilinear cross section of the bore may be generally cardioid or kidney-shaped. The bore may generally be of uniform cross-section along at least a major portion of its length, or may taper inwardly towards the forward end of the bore such that the longitudinal bore has a greater cross-sectional area at the rearward end than the forward end.

[0038] In some embodiments, an outer surface of the sidewall may be provided with ridges, ribs, grooves or other structure to help to retain the cartridge in place when inserted through an incision into the anterior chamber of a recipient's eye.

[0039] By tapering the structure of the cartridge from its rearward end to its forward end, it is possible to provide a large enough opening at the rearward end to facilitate insertion in coiling of the donor cornea implant as described hereinabove, while allowing the forward end and the blade portion to be narrower than hitherto possible. When making an incision into the surface of an eye, for example into the anterior chamber, it is better for the incision to be made as small as possible.

[0040] Moreover, by providing external ribs or grooves or ridges on at least a portion of the outer surface of the sidewall, it is possible to design the cartridge so that it tends to stay in place when inserted into the anterior chamber of an eye through a small incision and will tend to resist extrusion due to pressure from the inside of the anterior chamber.

The ribs or grooved or ridges are preferably configured to as to be substantially parallel to the sides of the incision when the cartridge is inserted into the anterior chamber.

[0041] In certain embodiments, the ridge element has an apex that is not sharply pointed, but instead has a rounded profile. This is in contrast to the protrusion disclosed in US2007/0244559, which is formed by the coming together of two separate pieces when the deformation chamber is closed, and which has a sharp apex. By providing a carefully-engineered, one-piece, smooth ridge element with a rounded profile, there is a much reduced risk of snagging or tearing the implant during insertion into and removal from the cartridge. The apex of the ridge element, in cross-section, may have a radius of curvature in a range from 0.05 to 0.2mm, preferably 0.09 to 0.13mm, for example around 0.11mm.

Each side of the ridge element, in cross-section, may have a radius of curvature in a range from 0.6 to 0.8mm, preferably 0.66 to 0.76mm, for example around 0.71mm. Taking the curvature of the apex of the ridge element as convex, the curvatures of the sides of are concave.

[0042] Preferred embodiments have a cross-section that forms a continuous curve with no corners or edges or other discontinuities. This can help to avoid unwanted folding or snagging of the implant during insertion, storage and ejection.

[0043] The cross-section of the bore and the shape of the ridge are configured such that an implant (biological implants are typically cut to standard sizes by way of corneal trephines, and artificial implants can be manufactured to standard sizes), when fully inserted into the bore of the cartridge, will assume a double coil configuration, with the endothelial surface of the implant facing inwardly and the opposed (stromal) surface of the implant touching the inner surface of the sidewall around its perimeter. The sides of the ridge element cause opposed edges of the implant to curl back towards the endothelial surface and to come gently to rest on the endothelial surface at a location opposed to the apex of the ridge element. The stromal surfaces of curled edge regions of the implant will contact each other back to back between the apex of the ridge element and the opposed location. In this way, the implant can assume a self-supporting, semi-rigid configuration in which the endothelial surface does not contact any part of the cartridge, and is thus protected from damage, but the coiled implant is provided with sufficient structural support by way of the opposed edges of the implant resting gently on the endothelial surface, and the back to back contact of the stromal surfaces of the edge regions.

[0044] This is in complete contrast to prior art arrangements, where it is emphasised that the opposed edges of the implant must in no circumstances touch the endothelial surface.

[0045] Careful investigations and experiments by the present Applicant have surprisingly revealed that the endothelial surface undergoes little if any damage as a result of this contact by the opposed edges of the implant, with the improved structural support thus provided far outweighing any potential disadvantage due to the endothelial contact. The importance of the improved structural support has become even more apparent with thinner implants, for example with thicknesses in the region of 7Opm and below.

BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which: Figure 1 shows a first embodiment from below; Figure 2 shows the first embodiment from above; Figure 3 shows the first embodiment from above in plan view; Figure 4 shows a vertical, longitudinal cross-section through the first embodiment; Figure 5 shows a second embodiment from above in plan view; Figure 6 shows the second embodiment provided with seals; Figures 7 to 9 show an embodiment provided with a handle portion; Figure 10 shows an embodiment in position on a preparation base; Figures 11 and 12 show a vertical, transverse cross-section through the first or second embodiments; and Figure 13 shows a vertical, longitudinal cross-section through an embodiment provided with a pusher.

DETAILED DESCRIPTION

[0047] Figure 1 shows a cartridge 1 of an embodiment from above. Figures 2 and 3 show the cartridge 1 from below, and Figure 4 shows a longitudinal cross-section through the cartridge 1. The cartridge 1 comprises a generally tubular portion 2 including a sidewall 3 defining a longitudinal bore 4 of curvilinear cross-section. The bore 4 is provided with a ridge elementS extending longitudinally along at least a portion of the bore 4 and projects inwardly thereinto from the sidewall 3.

[0048] A rearward end 6 of the cartridge 1 is provided with attaching structure 8 for disengageable attachment to a handle (see Figures 7 to 9). Flange structures 7 on the sidewall 3 are provided for disengageable attachment to a preparation base (see Figure 10).

[00491 A forward end 9 of the cartridge 1 is provided with a blade 10 for insertion through an incision in a recipient's eye. The blade 10 also provides a surface across which a donor implant can glide when being ejected from the bore 4.

[0050] In the embodiment of Figures 1 to 4, the bore 4 has a substantially constant cross-section, but in other embodiments, for example as shown in Figure 5, the bore 4 and the sidewall 3 may include a section that tapers inwardly from the rearward end 6 to the forward end 9. The embodiment of Figure 5 also includes ridges 11 on the sidewall 3, at least in the tapered section. These ridges 11 can help to maintain the cartridge 1 in position when it is inserted through an incision into a recipient's eye.

[0051] Figure 6 shows the cartridge of Figure 5 provided with removable seals 12, 13 at the rearward 6 and forward 9 ends respectively. The seals 12, 13 may naturally be provided for the embodiment of Figures 1 to 4 and other embodiments as well. The seals 12, 13 serve to seal the bore 4 at both ends, and allow an implant to be stored in the cartridge 1 together with a nutrient or saline solution. The cartridge 1 may thus be used for storing and transporting corneal implants ready for use in surgery.

[0052] Figures 7 to 9 show how a cartridge 1 may be connected to a handle 14 by way of the attaching structure 8 and complementary structure 15 on the handle 14. The handle includes a stopper 16 configured to seal the bore 4 at the rearward end 6 of the cartridge when fitted. This helps to prevent movement of the corneal implant in the bore 4 due to fluid flow when the forward end 9 of the cartridge 1 is inserted into a recipient's eye. The handle 14 may engage with the cartridge 1 by a snap-fit attachment. Ribs 17 or other indicia may be provided on one surface of the handle 14, as shown in Figure 9. In addition to providing a gripping surface, these indicia 17 help to indicate to a surgeon that the handle 14 and cartridge 1 are correctly oriented during surgery. It will be noted that the cartridge 1 and handle 14 may be configured for mutual attachment in only one relative orientation.

[0053] In some embodiments, the handle 14 may take the form of a syringe containing a suitable fluid, for example a biocompatible solution. When the cartridge 1 is correctly placed in an incision in a recipient's eye, the implant can be ejected from the cartridge and into the anterior chamber of the recipient's eye by operating the syringe to cause a fluid flow along the bore 4. The fluid flow will carry the implant out of the bore 4 and into the anterior chamber.

[0054] Figure 10 shows how a corneal implant 19 can be inserted into the bore 4 of the cartridge 1. The cartridge 1 is releasably engaged, by way of flange structure 7, with a preparation base 18 including a well 20 for temporarily holding the implant 19 prior to insertion into the bore 4. The implant 19 is placed in the well 20, endothelial surface facing upwardly, typically with a volume of nutrient or saline solution. A pair of forceps 21 is passed through the bore 4 from the forward end 9 of the cartridge 1. The forceps 21 emerge from the bore 4 at the rearward end 6 of the cartridge, and are used to grip an edge portion of the implant 19. The forceps 21 are then withdrawn through the bore 4 in the direction of the arrow, pulling the implant 19 into the cartridge 1. The ridge elementS (not shown in Figure 10) is uppermost in the bore 4, and causes the implant 19 to coil within the bore 4 into the desired double coil configuration (see Figure 12). When the implant 19 is properly located and coiled within the bore 4, the forceps 21 are released and withdrawn completely. The cartridge 1 may then be used for immediate surgery using the handle 14, or the rearward 6 and forward 10 ends of the bore 4 may be sealed and the cartridge 1 containing the implant 19 be stored and/or transported for later use in surgery.

[0055] Figures 11 and 12 show a transverse cross-section through a cartridge 1. The curvilinear cross-section of the bore 4 is clearly visible, and it can be seen that there are no sharp edges ordiscontinuities to cause snagging or tearing of an implant 19.

[0056] The bore 4 has a generally cardioid or kidney bean-shaped cross-section. The ridge element 5 has an apex 22 that is rounded, in contrast to certain prior art arrangements with a pointed apex. The height h of the apex 22 may be in a range from approximately 0.4 to 0.6mm, optionally approximately 0.52 to 0.56mm, optionally approximately 0.54mm. The width w of the apex may be in a range from approximately 0.16 to 0.26mm, optionally approximately 0.19 to 0.23mm, optionally approximately 0.21mm. The radius of curvature R1 of the apex may be in a range from approximately 0.05 to 0.2mm, optionally approximately 0.09 to 0.13mm, optionally approximately 0.11mm. The radii of curvature R2. R3 of each concave curved side of the ridge elementS may be in a range from approximately 0.6 to 0.8mm, optionally approximately 0.66 to 0.76mm, optionally approximately 0.71mm. R2 and R3 may be equal, although in some embodiments they may be different.

[0057] Figure 12 shows the corneal implant 19 in position within the bore 4 of the cartridge 1. The corneal implant 19 has an endothelial surface 24 and an opposed surface 23, which may be a stromal surface or a surface comprising at least a section of Descemet's membrane. The opposed surface 23 is typically less delicate than the endothelial surface 24, and can withstand contact with the sidewall 3 of the cartridge 1.

Indeed, the opposed surface 23 can be attracted to and held by the sidewall 3 by way of molecular adhesion forces.

[00581 The cross-section of the bore 4 and the shape of the ridge element 5 are configured such that the implant 19 assumes a double coil or tB'-shaped configuration, with the endothelial surface 24 of the implant 19 facing inwardly and the opposed (stromal) surface 23 of the implant 19 touching the inner surface of the sidewall 3 around its perimeter. The sides of the ridge element 5 cause opposed edges 27, 27' of the implant 19 to curl back towards the endothelial surface 24 and to come gently to rest on the endothelial surface 24 at a location 25 opposed to the apex 22 of the ridge element 5. The stromal surfaces 23 of curled edge regions of the implant 19 will contact each other back to back between the apex 22 of the ridge element 5 and the opposed location 25. In this way, the implant 19 assumes a stented configuration in which the endothelial surface 24 does not contact any part of the cartridge 1, and is thus protected from damage, but the coiled implant 19 is provided with sufficient structural support by way of the opposed edges 27, 27' of the implant 19 resting gently on the endothelial surface 24, and the back to back contact of the stromal surfaces 23 of the edge regions.

[0059] A nutrient or saline solution 26 may be provided in the bore 4 of the cartridge ito keep the implant moist and healthy.

[0060] In order to eject the implant 19 from the bore 4 of the cartridge 1 into a recipient's eye, the implant 19 may be pulled out using forceps (as disclosed, for example, in EP2491 890, or it may be pushed out of the cartridge 1 by way of a pusher 28, as shown in Figure 13. The use of a pusher 28 becomes more practicable due to the improved structural support provided by the stented configuration of the implant 19 in the cartridge.

The additional rigidity afforded by the contact between the opposed edges 27, 27' of the implant 19 with the endothelial surface 24 opposite the ridge element 5 means that collapse of the coiled implant 19 onto itself is avoided, and pushing the implant 19 out of the bore 4 becomes a workable solution.

[0061] An advantage of using a pushing arrangement, as opposed to the pulling arrangement disclosed in EP2491890, is that only a single incision needs to be made in the recipient's eye, as it is not necessary to make an additional incision to allow a pair of forceps to be inserted from the other side of the anterior chamber in order to grasp and pull the implant 19 into place.

[0062] Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of them mean "including but not limited to", and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps.

Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

[0063] Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments.

The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

[0064] The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

Claims

CLAIMS: 1. A cartridge including an endothelial corneal implant comprising a first, endothelial surface and a second, opposed surface, wherein the cartridge comprises a generally tubular portion including a sidewall defining a longitudinal bore of curvilinear cross section, wherein the longitudinal bore of the cartridge includes a ridge element extending longitudinally along at least a portion of the bore and projecting inwardly thereinto from the sidewall, wherein the implant is held in a B'-shaped configuration, the second surface of the implant facing the sidewall, with opposed edges of the implant being curled inwardly by the ridge element so as to rest gently on the first, endothelial surface of the implant at a location in the bore opposite the ridge element, and with opposed portions of the second surface of the implant contacting each other in the bore between the ridge element and the said location.
2. A cartridge for holding an endothelial corneal implant comprising a first, endothelial surface and a second, opposed surface, wherein the cartridge comprises a generally tubular portion including a sidewall defining a longitudinal bore of curvilinear cross section, wherein the longitudinal bore of the cartridge includes a ridge element extending longitudinally along at least a portion of the bore and projecting inwardly thereinto from the sidewall, wherein the ridge element is configured to hold the implant in a B'-shaped configuration, the second surface of the implant facing the sidewall, with opposed edges of the implant being curled inwardly by the ridge element so as to rest gently on the first, endothelial surface of the implant at a location in the bore opposite the ridge element, and with opposed portions of the second surface of the implant contacting each other in the bore between the ridge element and the said location.
3. A cartridge as claimed in claim 1 or 2, wherein the ridge element extends along substantially the whole bore.
4. A cartridge as claimed in any preceding claim, wherein the ridge element is a one-piece structure formed integrally with the sidewall.
5. A cartridge as claimed in any preceding claim, wherein the ridge element has a longitudinal apex.
6. A cartridge as claimed in claim 5, wherein the apex has a rounded cross-section.
7. A cartridge as claimed in claim 6, wherein the apex, in cross-section, has a radius of curvature in a range from approximately 0.05 to 0.2mm, optionally approximately 0.09 to 0.13mm, optionally approximately 0.11mm.
8. A cartridge as claimed in any preceding claim, wherein the ridge element, in cross-section, has concave curved sides.
9. A cartridge as claimed in claim 8, wherein each concave curved side, in cross-section, has a radius of curvature in a range from approximately 0.6 to 0.8mm, optionally approximately 0.66 to 0.76mm, optionally approximately 0.71mm.
10. A cartridge as claimed in any preceding claim, wherein at least a part of the longitudinal bore is tapered from a rearward end to a forward end of the cartridge.
11. A cartridge as claimed in any preceding claim, wherein the cartridge is open at forward and rearward ends thereof to allow access to the bore.
12. A cartridge as claimed in claim 11, further comprising sealing members for temporarily sealing the forward and rearward ends in fluid-tight manner so as to allow the implant to be stored in position inside the cartridge in a nutrient or saline solution.
13. A cartridge as claimed in claim 12, wherein the sealing members comprise at least one of: a cap, a bung and a stopper
14. A cartridge as claimed in claim 11 or 12 depending from claim 1, including a nutrient or saline solution sealed in the cartridge with the implant.
15. A cartridge as claimed in claim 1 or any one of claims 3 to 14 depending from claim 1, wherein the implant has a self-supporting configuration in which the endothelial surface does not contact any part of the cartridge, wherein the implant is sufficiently structurally supported by way of the opposed edges of the implant resting gently on the endothelial surface, and opposed portions of the second surface of the implant contacting each other in the bore between the ridge element and the said location, to prevent collapse of the implant when pushed from the bore of the cartridge.
16. A cartridge as claimed in any preceding claim, further provided with a pusher member for pushing the implant out of the bore and into an anterior chamber of a recipient's eye.
17. A cartridge as claimed in any one of claims 1 to 15, further provided with a fluid dispenser for causing a fluid flow along the bore so as to eject the implant from the bore and into an anterior chamber of a recipient's eye.
18. A method of retaining an endothelial corneal implant in a cartridge, the cartridge comprising a generally tubular portion including a sidewall defining a longitudinal bore of curvilinear cross section, the longitudinal bore of the cartridge including a ridge element extending longitudinally along at least a portion of the bore and projecting inwardly thereinto from the sidewall, and the implant comprising a first, endothelial surface and a second, opposed surface, wherein the implant is inserted into the bore of the cartridge so as to assume a B-shaped configuration, the second surface of the implant facing the sidewall, with opposed edges of the implant being curled inwardly by the ridge element so as to rest gently on the first, endothelial surface of the implant at a location in the bore opposite the ridge element, and with opposed portions of the second surface of the implant contacting each other in the bore between the ridge element and the said location.
19. A method according to claim 18, wherein the cartridge is open at forward and rearward ends thereof to allow access to the bore.
20. A method according to claim 19, wherein the implant is inserted into the bore of the cartridge by inserting a pair of forceps through the bore from the rearward end towards the forward end, grasping the implant with the forceps, retracting the forceps through the bore, and releasing the implant when the implant is properly positioned in the B-shaped configuration.
21. A method according to claim 19, wherein the implant is inserted into the bore of the cartridge by means of a flow of liquid.
22. A method according to any one of claims 19 to 21, wherein the forward and rearward ends of the bore are sealed with removable sealing members after the implant is inserted.
23. A cartridge substantially as hereinbefore described with reference to or as shown in the accompanying drawings.
24. A method of retaining an endothelial corneal implant in a cartridge substantially as hereinbefore described with reference to or as shown in the accompanying drawings.