Implant for treating glaucoma

Abstract

The invention relates to an implant for reducing ocular hypertension. Said implant can be used in particular to prevent and treat glaucomas that are emerging or occur. In particular, the implant is an implant (10) for the Schlemm's canal, which comprises a bridge (20), which has a first end point (22) and a second end point (24) and a first support region (26), a second support region (28), and a connecting piece (30), the bridge (20) extending along a first line (L1) from the first end point (22) to the second end point (24) across the first support region (26), the connecting piece (30), and the second support region (28) and the connecting piece (30) having a first cross-sectional area on average along the first line (L1) and the first support region (26) having a second cross-sectional area on average along the first line (L1) after the implantation, characterized in that the second cross-sectional area is at least 50% larger than the first cross-sectional area.

Claims

1. An implant (10) for implantation into the Schlemm's canal, said implant comprising a bridge (20) with a first end point (22) and a second end point (24) and a first support region (26), a second support region (28) and a connecting piece (30), wherein the bridge (20) extends along a first line (L1) from the first end point (22) to the second end point (24) across the first support region (26), the connecting piece (30) and the second support region (28), wherein the first end point (22) and the second end point (24) are the longitudinally outermost portions of said implant, and wherein the connecting piece (30) has a first cross-sectional area on average along the first line (L1) and the first support region (26) following implantation has a second cross-sectional area on average along the first line (L1), characterised in that the second cross-sectional area is at least 50% larger than the first cross-sectional area, and at least the connecting piece (30) is solid without cavities.

2. The implant (10) according to claim 1, wherein the second support region (28) following implantation has a third cross-sectional area on average along the first line (L1), and the third cross-sectional area is at least 50% larger than the first cross-sectional area.

3. The implant (10) according to claim 1, wherein the first support region (26) for implantation can be transferred into a position in which said implant along the first line (L1) has a fourth cross-sectional area on average, which is no more than 40% larger than the first cross-sectional area.

4. The implant (10) according to claim 1, wherein the second support region (28) for implantation can be transferred into a position in which it has along the first line (L1) a fifth cross-sectional area on average, which is no more than 40% larger than the first cross-sectional area.

5. The implant (10) according to claim 1, wherein the first support region (26) and/or the second support region (28) adopt/adopts a spiral form following implantation.

6. The implant (10) according to claim 1, wherein the first support region (26) and/or the second support region (28) is/are fabricated from a shape-memory alloy.

7. The implant (10) according to claim 1, wherein the connecting piece (30) is flexible.

8. The implant (10) according to claim 1, wherein the connecting piece (30) has a lower flexural rigidity compared to the first support region (26).

9. The implant (10) according to claim 1, wherein the connecting piece (30) is distance-stable.

10. The implant (10) according to claim 1, wherein the length of the connecting piece (30) exceeds the diameter thereof by a factor of at least 10.

11. The implant (10) according to claim 1, said implant after implantation adopting a position in which the first line (L1) is curved and runs in a first plane (E1) and has at least one tube (36), which enables fluid conduction through the first plane (E1).

12. The implant (10) according to claim 11, wherein the at least one tube (36) has a diameter which makes up less than 10% of the length of the connecting piece (30).

13. The implant (10) to prevent and treat an increased intraocular tension and/or glaucoma according to claim 1.

14. Use of an implant (10) according to claim 1 to prevent and treat an increased intraocular tension and/or glaucoma.

15. The implant according to claim 11 wherein said at least one tube (36) is oriented perpendicularly to the first plane (E1).

16. The implant (10) according to claim 2, wherein the first support region (26) for implantation can be transferred into a position in which said implant along the first line (L1) has a fourth cross-sectional area on average between the first and the second cross-sectional areas, which is no more than 40% larger than the first cross-sectional area, and wherein the second support region (28) for implantation can be transferred into a position in which it has along the first line (L1) a fifth cross-sectional area on average between the first and the third cross-sectional areas, which is no more than 40% larger than the first cross-sectional area.

17. The implant (10) according to claim 2, wherein the second and the third cross-sectional areas are from 10,000 μm.sup.2 to 100,000 μm.sup.2.

18. The implant (10) according to claim 1, wherein the second cross-sectional area is at least 75% larger than the first cross-sectional area.

19. The implant (10) according to claim 5, wherein the spiral form is a spiral formed radially around the first line (L1).

Description

(1) These features of the invention are described in combination in the figures and in the associated descriptions. However, these features can also be comprised in other combinations by an object according to the invention. Each disclosed feature is thus also to be considered as disclosed in technically feasible combinations with other features. The figures are slightly simplified and schematic in part.

(2) FIG. 1 shows an implant according to the invention in a storage configuration;

(3) FIG. 2 shows a corresponding implant in a configuration immediately prior to implantation;

(4) FIG. 3 shows another implant according to the invention in a configuration that corresponds largely to the position adopted following implantation;

(5) FIG. 4 shows a schematic perspective illustration of a human eye;

(6) FIG. 5 shows a cross-sectional illustration of a region of the human eye;

(7) FIG. 6 shows a corresponding, but enlarged cross-sectional illustration of a cross-section through the eye following insertion of the implant;

(8) FIG. 7 shows, in a view corresponding to FIG. 6, a displaced parallel cross section through the eye;

(9) FIG. 8 shows, in a cross-sectional view displaced compared to FIG. 6 and FIG. 7, a further cross section through the eye.

(10) FIG. 1 shows an implant according to the invention in a configuration in which it could be stored, for example. The implant in this embodiment consists only of the bridge 20. The bridge 20 has a first end point 22 to the left. This is adjoined by a first support region 26. The second end point 24 is located opposite, in a mirror image, and is adjoined by the second support region 28. Both support regions are interconnected by a connecting piece. The support regions are spiralled in this configuration, such that a first spiral 32 is located in the first support region and a second spiral 34 is located opposite in the second support region 28.

(11) FIG. 2 shows the same implant in another configuration. The implant can be brought into this configuration immediately prior to an operation. The implant has no spiralled ends, but the first support region 26 and the second support region 28 each have the form of stretched round pieces. They join the connecting piece 30 integrally and in a form-fitting manner. The implant can be transferred into such a form by cooling, for example.

(12) FIG. 3 shows another implant according to the invention. This has the component parts of the bridge that are already known. This implant, however, additionally has three tubes, which are arranged equidistantly on the connecting piece 30. As a result, the distance between the first tube 36 and the second tube 38 is exactly the same as the distance between the second tube 38 and the third tube 40. An equidistant arrangement of the tubes is advantageous, but is not absolutely necessary. These tubes are used as a fluid conduction device, and the more precise function thereof will be illustrated in greater detail hereinafter based on the anatomy of the eye. The broken lines transverse to the line of extension of the bridge 20 are reproduced based on the implant 10 and will be illustrated hereinafter in FIG. 6 and FIG. 7 and FIG. 8.

(13) In FIG. 3 the bridge is shown on the whole in a curved position. Here, the connecting piece 30 is curved in particular. In this curved position, the implant adapts particularly well to the course of the Schlemm's canal.

(14) As shown in FIGS. 1-3 the first end point (22) and the second end point (24) are the longitudinally outermost portions of the implant. FIG. 3 also illustrates the support regions (26,28) to have a spiral form which is formed radially around the first line (L1).

(15) FIG. 4 shows a schematic perspective illustration of the eye. At the top, the cornea H can be seen, and in the middle thereof the iris I. The cornea is surrounded by the sclera Sk.

(16) In order to enable an improved discharge of the aqueous humour, surgical access to the Schlemm's canal S may have to be found. An appropriate operation would conventionally be carried out from outside. Here, a significant part of the sclera Sk would be opened. This could occur in a conventional operative field K. As indicated in the drawing, the operative field could be selected to be larger or smaller depending on the angle over which the Schlemm's canal should be made accessible.

(17) The implant of the present invention, however, should be used in conjunction with a minimally invasive operation. This is a key aspect in order to acknowledge the advantages of the present invention. The implant has very small dimensions and is suitable for implantation involving minimal surgery. The general operation direction here is the direction O. The access to the Schlemm's canal S is thus found perpendicularly through the cornea.

(18) The parts of the eye important for comprehension of the present invention are also reproduced in the overall illustration of FIG. 5. This is a cross-sectional illustration in which the posterior chamber of eyeball hA and the vitreous humour G of the eye are located on the right-hand side and the cornea H is located on the left-hand side. The lens L and the iris I are located therebetween.

(19) Aqueous humour finds its way from the direction of the vitreous humour past the lens L and flows around the iris I, such that the aqueous humour passes from the posterior chamber of eyeball hA into the anterior chamber of eyeball vA. In the case of a healthy eye it is then forwarded on through the trabecular meshwork. The trabecular meshwork T transitions into the front wall vW of the Schlemm's canal S (wherein this transition is without sharp boundary). The Schlemm's canal lies in the sclera Sk. It is delimited outwardly by a rear wall hW (from the viewpoint of the surgeon).

(20) FIG. 6 shows an enlarged detail from FIG. 5. In this detail a surgical technique is sketched, which plays a role in conjunction with the present invention. In the case of a glaucoma patient the trabecular meshwork T is no longer permeable to aqueous humour or is no longer sufficiently permeable to aqueous humour. This therefore can no longer be drained through the Schlemm's canal. It is possible in a minimally invasive intervention to remove part of the trabecular meshwork (substantially by scalpel and also heat action). A very advantageous surgical instrument for such an intervention is the trabectome. This occurs from the direction of surgery O. Here, parts of the front wall vW of the Schlemm's canal S can also be removed. The removal occurs here over a limited angular range, for example over 30°, 45° or also 90° and is also indicated in FIG. 4. (The angles are thus based on the angle of 360° covered by the Schlemm's canal as circular vessel.)

(21) This surgical technique leaves behind minimal damage on the eye and has proven to be very effective. However, the long-term effect of the operation is not always completely satisfactory.

(22) In conjunction with the present invention it has been identified that the remaining Schlemm's canal cannot always perform its function efficiently. As has been identified, a deficient mechanical stability of the remaining Schlemm's canal contributes to this.

(23) The implant of the present invention can be used at the point at which the Schlemm's canal was removed. The implant length is thus to be matched to the length of the Schlemm's canal. In an adult the Schlemm's canal typically has a diameter from 12 to 14 mm. Accordingly, the Schlemm's canal typically has a circumference from 50 to 75 mm. If, in the case of a Schlemm's canal of 50 mm circumference, an angular segment of 30° is removed, a gap of a good 4 mm would thus remain. The implant should then have a length of more than 4 mm. It is generally expedient if, for described case, the connecting piece has a length of exactly 4 mm and the support regions each have a length of approximately 1 mm. These specified length are only approximate, and a surgeon will choose an implant for the respective application under consideration of many auxiliary conditions.

(24) Since the first support region is inserted in a first opened portion of the Schlemm's canal and the second support region is inserted in a second opened remaining region of the Schlemm's canal, a strong mechanical stabilisation is achieved.

(25) A distance-stable connecting piece contributes to this and fixes the position of the resultant end piece of the Schlemm's canal on the circumferential line around the cornea.

(26) The mechanical stabilisation of the remaining end portions of the Schlemm's canal in the direction of the cross section shown in FIG. 5 is just as important.

(27) This effect can be seen once more in FIG. 6. The support region is inserted into the Schlemm's canal S such that this better withstands pressure which is effective within the plane of illustration.

(28) FIG. 7, with a further cross-sectional view, shows the position of the implant. As indicated in FIG. 3, only a cross-sectional area through the connecting piece 30 can be seen in this view.

(29) FIG. 8 shows a further cross-sectional view. In this cross-sectional view the position of a tube 40 can be seen. This tube is introduced into the tissue of the rear wall hW. It is advantageously fitted precisely in a collecting duct located there. The tube diameter for the purpose should be 20% to 50% larger than the diameter of the collecting duct.

(30) It is advantageous if the tube protrudes over approximately 20% to 30% of the length thereof from the tissue (i.e. into the region of the opened Schlemm's canal). This prevents tissue from growing into the tube and closing said tube. The tube 40 can also be equipped with an edge 42, which also helps to hold tissue away from the tube inlet.

(31) It has also proven to be advantageous if the tubes have smooth walls, since otherwise an unfavourable intergrowth with tissue or also an ingrowth of the newly created fluid drainage path would be observed.

(32) The description has also made it clear that the implant according to the invention is not a stent in the conventional sense. A stent in the conventional sense is used to widen a vessel, for example a blood vessel, so as to thus improve the flow of fluid therethrough. The present implant by contrast bridges a gap created by removal of vessel material. In this respect the function of said implant goes beyond that of a stent.

(33) Within the scope of the invention it has been found that when bridging such a gap in the Schlemm's canal a key additional effect is provided. In the regions in which parts of the Schlemm's canal have been removed and damage to the tissue by mechanical influence or by heat potentially also cannot be ruled out entirely, an improved fluid drainage is achieved. Fluid is conducted into the rear wall and therefore into the sclera Sk. From there, the fluid is drained regularly. This is achieved already by an implant without tubes, but particularly by an implant with tubes.

(34) On the whole it has been made clear how the effects of a minimally invasive operation could be considerably improved with the implant according to the invention. These improvements concern the volume of the aqueous humour drainage, but also the stability over time of the effect.

LIST OF REFERENCE SIGNS

(35) 10 implant

(36) 20 bridge

(37) 22 first end point

(38) 24 second end point

(39) 26 first support region

(40) 28 second support region

(41) 30 connecting piece

(42) 32 first spiral

(43) 34 second spiral

(44) 36 first tube

(45) 38 second tube

(46) 40 third tube

(47) 42 edge

(48) hA posterior chamber of eyeball

(49) vA anterior chamber of eyeball

(50) G vitreous humour

(51) H cornea

(52) I iris

(53) K conventional operative field

(54) L lens

(55) O minimally invasive direction of operation

(56) T trabecular meshwork

(57) Sk sclera

(58) S Schlemm's canal

(59) vW front wall of the Schlemm's canal

(60) hW rear wall of the Schlemm's canal

(61) L1 first line

(62) E1 first plane