A SHUNT AND METHOD FOR TREATING GLAUCOMA

Abstract

A shunt 200 for treating glaucoma in a patient during and/or after vitreoretinal surgery involving the use of a tamponading agent comprising a gas or oil bubble 50. The shunt includes a tubular body 12 having a proximal end 14 which is implantable in the vitreous cavity C of a patient and a distal end which is implantable in the subarachnoid space of the patient. The tubular body defines a lumen 18 extending between the distal and proximal ends. The shunt includes an occlusion body 32 defining a number of micro-passages 34 inflow communication with the lumen 18. The micro-passages are configured in terms of their size and number to provide sufficient surface tension and viscosity resistance in order to prevent the tamponading agent from passing through the micro-passages into the lumen, yet allow sufficient aqueous fluid from the vitreous cavity to travel along the micro-passages into the lumen 18 in order to regulate intraocular pressure.

Claims

1. A shunt for treating glaucoma in a patient during and/or after vitreoretinal surgery involving use of a tamponading agent, the shunt including a tubular body having a proximal end which is implantable in an ocular chamber of the patient and a distal end which is implantable in an extra-ocular space of the patient, the tubular body defining a lumen extending between the distal and proximal ends, the shunt including occlusion means for at least partially occluding the lumen so as to prevent the tamponading agent from entering the extra-ocular space.

2. The shunt as claimed in claim 1, wherein the shunt is adapted for use in vitreoretinal surgery involving the use of the tamponading agent comprising a gas or oil bubble, the occlusion means including a foraminous body covering the lumen of the tubular body adjacent the proximal end thereof.

3. The shunt as claimed in claim 2, wherein the foraminous body defines a number of micro-passages leading into the lumen, wherein a number and size of the micro-passages provide the foraminous body with sufficient surface tension and viscosity resistance in order to prevent tamponading agents comprising gas bubbles or oil bubbles from passing through the micro-passages into the lumen, yet allow sufficient aqueous fluid to travel along the micro-passages to the lumen in order to regulate intraocular pressure.

4. The shunt as claimed in claim 3, wherein the micro-passages are configured for use in regulating intraocular pressures in a range between 5 mmHg and 60 mmHg.

5. The shunt as claimed in claim 3, wherein the foraminous body is of a hydrophilic material for promoting a flow of aqueous fluid into the lumen.

6. The shunt as claimed in claim 3, wherein the foraminous body is of an oleophobic material for use with the tamponading agent comprising an oil bubble, for resisting a flow of oil into the lumen.

7. The shunt as claimed in claim 1, wherein the shunt is adapted for use in vitreoretinal surgery involving the use of the tamponading agent comprising a gas or oil bubble, the occlusion means comprising a valve member which is located adjacent the proximal end of the tubular body and which is acted upon by surface tension of the gas or oil bubble causing displacement of the valve member into a condition where the valve member at least partially occludes the lumen.

8. The shunt as claimed in claim 7, wherein the valve member comprises a flap valve which is hingedly connected to the tubular body at its proximal end, the flap valve being hingedly displaceable between a closed position wherein a flap at least partially occludes the lumen when acted upon by the gas or oil bubble, preventing the gas or oil bubble from passing into the lumen and an open position wherein the lumen is not occluded, allowing aqueous fluid to flow along the lumen in order to adequately regulate intraocular pressure.

9. The shunt as claimed in claim 8, wherein the flap valve is connected to the tubular body in an arrangement wherein the flap valve is biased into the open position.

10. The shunt as claimed in claim 7, wherein the valve member comprises a flexible tube valve which is sealingly connected to the tubular body at its proximal end, the tube valve defining an internal passage which is in flow communication with the lumen of the tubular body.

11. The shunt as claimed in claim 10, wherein the tube valve is configured to bend when acted upon by surface tension of the gas bubble or oil bubble thereby at least partially occluding the passage and preventing the gas or oil bubble from passing along the passage and entering the lumen of the tubular body.

12. The shunt as claimed in claim 11, wherein the tube valve is resiliently deformable so as to be displaceable between a closed position wherein the tube valve is bent so as to at least partially occlude the passage thereof when acted upon by the gas or oil bubble, preventing the gas or oil bubble from passing into the passage and an open position wherein the passage is not occluded, allowing aqueous fluid to flow along the passage into the lumen of the tubular body in order to adequately regulate intraocular pressure.

13. The shunt as claimed in claim 12, wherein the tube valve comprises a resiliently deformable first tube valve element which is sealingly connected to the tubular body and a deformable second tube valve element which is connected to an end of the first tube valve element, the first and second tube valve elements defining a common passage which is in flow communication with the lumen of the tubular body.

14. The shunt as claimed in claim 13, wherein the second valve element is of a relatively stiffer construction than construction of the first tube valve element, thereby providing the tube valve with a structure having variable stiffness wherein a distal end region of the tube valve defined by the second valve element is stiffer than a proximal end region of the tube valve defined by the first valve element.

15. The shunt as claimed in claim 14, wherein the second tube valve element is displaceable between a) a valve closing position wherein the second tube valve element bends when acted upon by a gas or oil bubble, causing a bending force to be exerted in turn on the first tube valve element resulting in bending of the first tube valve element and causing the passage defined by the first tube valve element to at least partially occlude, thereby preventing the gas or oil bubble from passing into the passage and the lumen of the tubular body; and b) a valve opening position wherein the second tube valve element is not acted upon by the gas or oil bubble, allowing the first tube valve element to return to a naturally open position wherein the passage defined thereby is not occluded, allowing aqueous fluid to flow along the lumen of the tubular body in order to adequately regulate intraocular pressure.

16. The shunt as claimed in claim 1, wherein the shunt is adapted for use in vitreoretinal surgery involving the use of the tamponading agent, the occlusion means comprising a plug which is removably attached to the proximal end of the tubular body in order to occlude the lumen, preventing the tamponading agent from passing into the lumen.

17. The shunt as claimed in claim 16, wherein the plug is fitted to the tubular body during a vitreoretinal surgical procedure by a surgeon and thereafter removed once the tamponading agent is no longer present in the vitreous cavity.

18. The shunt as claimed in claim 1, wherein the shunt is adapted for use in vitreoretinal surgery involving the use of the tamponading agent, the occlusion means comprising a dissolvable membrane which is attached to the tubular body at its proximal end so as to cover the proximal end, thereby occluding the lumen and preventing the tamponading agent from passing into the lumen.

19. The shunt as claimed in claim 18, wherein the membrane is of a material which dissolves over a period of time so as to no longer occlude the lumen of the tubular body, coinciding with the tamponading agent no longer being present.

20. The shunt as claimed in claim 1, wherein the shunt is adapted for use in vitreoretinal surgery involving the use of the tamponading agent, the occlusion means comprising a laserable membrane which is attached to the proximal end of the tubular body in order to occlude the lumen, preventing the tamponading agent from passing into the lumen.

21. The shunt as claimed in claim 20, wherein the membrane is punctured by a surgeon using a laser once the tamponading agent is no longer present in the vitreous cavity.

22. A method for treating glaucoma in a patient during and/or after vitreoretinal surgery, the method including: providing a shunt for treating glaucoma in a patient during and/or after vitreoretinal surgery involving use of a tamponading agent, the shunt including a tubular body having a proximal end which is implantable in an ocular chamber of the patient and a distal end which is implantable in an extra-ocular space of the patient, the tubular body defining a lumen extending between the distal and proximal ends, the shunt including occlusion means for at least partially occluding the lumen so as to prevent the tamponading agent from entering the extra-ocular space; making at least one incision in a pars plana region of a sclera of the patient; removing vitreous jelly from a vitreous cavity via the incision and replacing the vitreous jelly with a saline solution; advancing the distal end of the shunt through retinal nerve fibres and scleral tissue to enter an orbital subarachnoid space between an optic nerve and an optic nerve sheath; leaving the proximal end of the shunt within the vitreous cavity; and replacing an amount of saline solution in the vitreous cavity with the surgical tamponading agent in the form of gas or oil.

23. The method as claimed in claim 22, wherein the distal end of the shunt is implantable in the subarachnoid space of the patient, the distal end of the shunt being advanced through the scleral tissue in the inferior or superior quadrants approximately 0.5-1.5 mm from an optic nerve head in order to avoid important blood vessels.

24. The method as claimed in claim 22, wherein the distal end of the shunt is implantable in the subarachnoid space of the patient, the distal end of the shunt being advanced through the retinal nerve fibres in inferior, medial or superior quadrants to limit damage to important macular retinal nerve fibres.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Further features of the invention are described hereinafter by way of a non-limiting example of the invention with reference to and as illustrated in the accompanying diagrammatic drawings. In the drawings:

[0036] FIG. 1 shows a cross-sectional view of a human eye;

[0037] FIG. 2 shows a side view of a shunt in accordance with a first example of a first embodiment of the invention with the flap valve in an open position;

[0038] FIG. 3 shows a three-dimensional view of the shunt of FIG. 2;

[0039] FIG. 4 shows a side view of the shunt of FIG. 2 with the flap valve in a closed position;

[0040] FIG. 5 shows a three-dimensional view of the shunt of FIG. 4;

[0041] FIG. 6-8A illustrate the manner in which the shunt of FIG. 2 is implanted and used during a vitreoretinal surgical procedure including the use of a gas bubble as a tamponading agent;

[0042] FIG. 9 shows a side view of a second example of the first embodiment of a shunt in accordance with the invention, in an undeformed state wherein the lumen is open;

[0043] FIG. 10 shows a three-dimensional view of the shunt of FIG. 9;

[0044] FIG. 11 shows a side view of the shunt of FIG. 9 in a bent deformed state wherein the lumen is occluded;

[0045] FIG. 12 shows a three-dimensional view of the shunt of FIG. 11;

[0046] FIGS. 13-15A illustrate the manner in which the shunt of FIG. 9 is implanted and used during a vitreoretinal surgical procedure including the use of a gas bubble as a tamponading agent;

[0047] FIG. 16 shows a side view of a second embodiment of a shunt in accordance with the invention;

[0048] FIG. 17 shows a three-dimensional view of the shunt of FIG. 16;

[0049] FIGS. 18 and 19 show enlarged fragmentary side views of the shunt of FIG. 16 implanted showing the lumen open and occluded by a gas bubble, respectively;

[0050] FIG. 19A shows enlarged fragmentary side view of detail 19A of FIG. 19;

[0051] FIG. 20 shows a side view of a third embodiment of a shunt in accordance with the invention;

[0052] FIG. 21 shows an enlarged fragmentary exploded sectional side view of the shunt of FIG. 20; and

[0053] FIG. 22 shows a three-dimensional view of the shunt of FIG. 20.

DETAILED DESCRIPTION OF THE INVENTION

[0054] With reference to FIG. 1 of the drawings, a cross-sectional view illustrating anatomical parts of a human eye 2 which are required for use in the description which follows below, comprises: [0055] A: Anterior chamber filled with aqueous fluid [0056] B: Posterior chamber filled with aqueous fluid [0057] C: Vitreous cavity filled with vitreous jelly [0058] D: Sclera [0059] E: Retina [0060] F: Zonule fibres [0061] G: Choroid [0062] H: Cornea [0063] I: Ciliary body [0064] J: Lamina cribrosa [0065] K: Optic nerve [0066] L: Optic nerve sheath [0067] M: Orbital subarachnoid space filled with cerebrospinal fluid [0068] N: Ocular globe [0069] O: Lens

[0070] With reference to FIGS. 2 to 8A of the drawings, a first example of a first embodiment of a shunt in accordance with the invention, is designated generally by the reference numeral 10. The shunt 10 is adapted for implantation in the human body so as to provide for flow communication between aqueous fluid in the vitreous cavity C of the eye and cerebrospinal fluid in the orbital subarachnoid space M surrounding the optic nerve K. More specifically, the shunt is configured for treating glaucoma in a patient during and/or after vitreoretinal surgery involving the use of a tamponading agent. The shunt 10 when implanted, regulates intraocular pressure in the eye of the patient. For the treatment of glaucoma, the shunt permits aqueous fluid to drain from the vitreous cavity C of the eye into the subarachnoid space M, thereby reducing intraocular pressure.

[0071] The shunt 10 includes a tubular body 12 having a proximal end 14 which is implantable in the vitreous cavity C of a patient and a distal end 16 which is implantable in an extra-ocular space of the patient such as the subarachnoid space M of the patient. The tubular body defines a lumen 18 extending between the distal and proximal ends.

[0072] The shunt defines three stop formations in the form of longitudinally-spaced circumferential grooves 20 for resisting migration of the tubular body following insertion of the tubular body into the subarachnoid space.

[0073] A distal end region of the tubular body tapered towards the distal end 16 of the tubular body. The distal end of the tubular body has a pencil point, non-cutting surface profile.

[0074] The tubular body defines a proximal opening 22 at the proximal end 14, leading into the lumen. The tubular body defines four distal openings 24 in a side wall of the distal end region, leading into the lumen.

[0075] The tubular body is of a biocompatible material polymer and may incorporate an elutable therapeutic substance such as an antibiotic substance for preventing the spread of an infection between the ocular chamber and the subarachnoid space or an anticlotting agent for preventing blockage of adjacent blood vessels or the lumen of the tubular body by blood clots.

[0076] The shunt 10 further includes occlusion means comprising a valve member in the form of a flap valve 26 which is hingedly connected to the tubular body at its proximal end. The flap valve 26 is hingedly displaceable between an open position (as shown in FIGS. 2 and 3) wherein the flap is spaced from the opening 22 at the proximal end of the tubular body and a closed position (as shown in FIGS. 4 and 5) wherein the opening 22 is closed, completely occluding the lumen 18. The flap valve 26 is connected to the tubular body in an arrangement wherein the flap valve is biased into the open position.

[0077] With reference to FIGS. 6-8A, the manner in which the shunt 10 is implanted and used is illustrated.

[0078] A method for treating glaucoma in a patient during and/or after vitreoretinal surgery, using the shunt 10, in accordance with the invention, includes:

making at least one incision in the pars plana region of the sclera;
removing the vitreous jelly from the vitreous cavity via the incision and replacing it with a saline solution;
advancing the distal end of the shunt through retinal nerve fibres and scleral tissue to enter the orbital subarachnoid space between the optic nerve and optic nerve sheath;
leaving the proximal end of the shunt within the vitreous cavity; and
replacing an amount of saline solution in the vitreous cavity with a surgical tamponading agent in the form of a gas or oil.

[0079] The tamponading agent is in the form of a biocompatible gas or silicone oil bubble 50.

[0080] The shunt 10 is inserted inferiorly away from temporal paraoptic macular region, away from the PSPCA's and externally of the CZH blood vessel region. When inserting the shunt it is important to limit damage to important retinal nerve fibres as the shunt passes through retinal nerve fibres en route to the subarachnoid space. It is also important to prevent damage to the optic nerve head blood supply by avoiding damage to the PSPCA's and CZH en route to the subarachnoid space. The non-cutting tip of the distal end of the shunt and point of insertion plays an important role in this regard.

[0081] There is a tendency for surgical tamponades in the vitreous cavity to flow down the pressure gradient into the subarachnoid space. Here, they may cause injury to the optic nerve due to sudden increases in pressure from gaseous passage or inflammatory responses from silicone oil. The premature loss of tamponade from the vitreous cavity may also result in recurrence of retinal detachment.

[0082] The flap valve 26 is hingedly displaceable between a closed position wherein the flap completely occludes the lumen 18 when acted upon by the gas or oil bubble 50, preventing the gas or oil bubble from passing into the lumen and an open position wherein the lumen is not occluded, allowing aqueous fluid to flow along the lumen in order to adequately regulate intraocular pressure.

[0083] With reference to FIGS. 9-15A, a second example of the first embodiment of a shunt in accordance with the invention, is designated by the reference numeral 100. The shunt 100 is similar to the shunt 10 with a difference being that the shunt 100 has a differently configured valve member. Features of the shunt 100 which are the same as and/or similar to those of the shunt 10 are designated by the same and/or similar reference numerals in FIGS. 9-15A. The shunt 100 is implantable in the same manner as the shunt 10 and includes a tubular body 12 having a proximal end 14 which is implantable in the vitreous cavity C of a patient and a distal end 16 which is implantable in the subarachnoid space M of the patient. The tubular body defines a lumen 18 extending between the distal and proximal ends.

[0084] The shunt defines three stop formations in the form of longitudinally-spaced circumferential grooves 20 for resisting migration of the tubular body following insertion of the tubular body into the subarachnoid space.

[0085] A distal end region of the tubular body is tapered towards the distal end 16 of the tubular body. The distal end of the tubular body has a pencil-point, non-cutting surface profile.

[0086] The tubular body defines a proximal opening at the proximal end 14, leading into the lumen. The tubular body defines four distal openings 24 in a side wall of the distal end region, leading into the lumen.

[0087] The tubular body is of a biocompatible material polymer and may incorporate an elutable therapeutic substance such as an antibiotic substance for preventing the spread of an infection between the ocular chamber and the subarachnoid space or an anticlotting agent for preventing blockage of adjacent blood vessels or the lumen of the tubular body by blood clots.

[0088] The shunt 100 further includes occlusion means comprising a valve member in the form of a flexible tube valve 126 which is sealingly connected to the tubular body at its proximal end 14. The tube valve 126 defines an internal passage 118 which is in flow communication with the lumen 18 of the tubular body 12. The tube valve is configured to bend and as such is resiliently deformable. More specifically, the tube valve comprises a resiliently deformable first tube valve element 28 which is sealingly connected to the tubular body 12 at its proximal end and a deformable second tube valve element 30 which is connected to an end of the first tube valve element. The internal passage 118 extends through the first and second tube valve elements and is in flow communication with the lumen 18 of the tubular body 12. The second tube valve element 30 is of a relatively stiffer construction than the construction of the first tube valve element 28, thereby providing the tube valve 126 with a structure having variable stiffness wherein a distal end region of the tube valve defined by the second tube valve element 30 is stiffer than a proximal end region of the tube valve defined by the first tube valve element 28. The purpose of the variable stiffness will be explained in further detail below.

[0089] More specifically, the second tube valve element is resiliently displaceable between a valve closing position wherein the second tube valve element is bent when acted upon by the gas or oil bubble 50, causing a bending force to be exerted on the first tube valve element resulting in kinking of the first tube valve element and causing the passage 118 defined by the first tube valve element to at least partially occlude, thereby preventing the gas or oil bubble from passing into the passage 18 and the lumen 18 of the tubular body 12; and a valve opening position wherein the second tube valve element is not acted upon by the gas or oil bubble, allowing the first tube valve element to return to a naturally open position wherein the passage 118 defined thereby is not occluded, allowing aqueous fluid to flow along the lumen 18 of the tubular body 12 in order to adequately regulate intraocular pressure.

[0090] With reference to FIGS. 16-19A, a second embodiment of a shunt in accordance with the invention, is designated by the reference numeral 200. The shunt 200 is similar to the shunts 10 and 100 with a difference being that the shunt 200 has differently configured occlusion means. Features of the shunt 200 which are the same as and/or similar to those of the shunt 10 are designated by the same and/or similar reference numerals in FIGS. 16-19. The shunt 200 is implantable in the same manner as the shunts 10 and 100 and includes a tubular body 12 having a proximal end 14 which is implantable in the vitreous cavity C of a patient and a distal end 16 which is implantable in the subarachnoid space M of the patient. The tubular body defines a lumen 18 extending between the distal and proximal ends.

[0091] The shunt 200 defines three stop formations in the form of longitudinally-spaced circumferential grooves 20 for resisting migration of the tubular body following insertion of the tubular body into the subarachnoid space.

[0092] A distal end region of the tubular body is tapered towards the distal end 16 of the tubular body. The distal end of the tubular body has a pencil-point, non-cutting surface profile.

[0093] The tubular body 12 defines a proximal opening at the proximal end 14, leading into the lumen. The tubular body defines four distal openings 24 in a side wall of the distal end region, leading into the lumen.

[0094] The tubular body is of a biocompatible material polymer and may incorporate an elutable therapeutic substance such as an antibiotic substance for preventing the spread of an infection between the ocular chamber and the subarachnoid space or an anticlotting agent for preventing blockage of adjacent blood vessels or the lumen of the tubular body by blood clots.

[0095] The shunt 200 further includes occlusion means comprising a foraminous occlusion body 32 which is fitted onto the proximal end of the tubular body 12. The occlusion body 32 defines a number of micro-passages 34 which are in flow communication with the lumen 18 of the tubular body.

[0096] The shunt 200 is adapted for use in vitreoretinal surgery involving the use of a tamponading agent comprising a gas or oil bubble 50. The micro-passages are configured in terms of their size and number to provide sufficient surface tension and viscosity resistance in order to prevent tamponading agents comprising gas bubbles or oil bubbles from passing through the micro-passages into the lumen, yet allow sufficient aqueous fluid from the vitreous cavity to travel along the micro-passages into the lumen 18 in order to regulate intraocular pressure. This configuration permits the micro-passages 34 to be used to regulate intraocular pressures in a range between 5 mmHg and 60 mmHg. The occlusion body may be of a hydrophilic material for use with an oil or gas bubble tamponading agent for promoting a flow of aqueous fluid into the lumen. For use with an oil bubble tamponading agent, the occlusion body may additionally or alternatively, be of an oleophobic material for resisting a flow of oil into the lumen.

[0097] With reference to FIGS. 20 to 22, a third embodiment of a shunt in accordance with the invention, is designated by the reference numeral 300. The shunt 300 is similar to the shunts 10, 100 and 200 with a difference being that the shunt 300 has a differently configured occlusion means. Features of the shunt 300 which are the same as and/or similar to those of the shunt 10 are designated by the same and/or similar reference numerals in FIGS. 16-19. The shunt 300 is implantable in the same manner as the shunts 10, 100 and 200 and includes a tubular body 12 having a proximal end 14 which is implantable in the vitreous cavity C of a patient and a distal end 16 which is implantable in the subarachnoid space M of the patient. The tubular body defines a lumen 18 extending between the distal and proximal ends.

[0098] The shunt 300 defines three stop formations in the form of longitudinally-spaced circumferential grooves 20 for resisting migration of the tubular body following insertion of the tubular body into the subarachnoid space.

[0099] A distal end region of the tubular body 12 is tapered towards the distal end 16 of the tubular body. The distal end of the tubular body has a pencil-point, non-cutting surface profile.

[0100] The tubular body defines a proximal opening at the proximal end 14, leading into the lumen. The tubular body defines four distal openings 24 in a side wall of the distal end region, leading into the lumen.

[0101] The tubular body is of a biocompatible material polymer and may incorporate an elutable therapeutic substance such as an antibiotic substance for preventing the spread of an infection between the ocular chamber and the subarachnoid space or an anticlotting agent for preventing blockage of adjacent blood vessels or the lumen of the tubular body by blood clots.

[0102] The shunt 200 further includes occlusion means comprising a plug 38 which is removably attached to the proximal end of the tubular body in order to completely occlude the lumen, preventing the tamponading agent from passing into the lumen. More specifically, the tubular body defines a socket 40 at its proximal end, into which the plug 38 is sealingly fitted during a vitreoretinal surgical procedure by a surgeon and thereafter removed once the tamponading agent is no longer present in the vitreous cavity, allowing aqueous to drain into the subarachnoid space via the lumen 18.

[0103] The invention extends to a fourth embodiment of a shunt in accordance with the invention, wherein the shunt is adapted for use in vitreoretinal surgery involving the use of a tamponading agent, and wherein the occlusion means comprises a dissolvable membrane which is attached to the tubular body 12 at its proximal end 14 so as to cover the proximal end, thereby occluding the lumen and preventing the tamponading agent from passing into the lumen. More specifically, the membrane is of a material which dissolves over a period of time so as to no longer occlude the lumen of the tubular body, coinciding with the tamponading agent no longer being present.

[0104] The invention extends to a fifth embodiment of a shunt in accordance with the invention, wherein the shunt is adapted for use in vitreoretinal surgery involving the use of a tamponading agent, the occlusion means may comprise a laserable membrane which is attached to the proximal end 14 of the tubular body 12 in order to occlude the lumen, preventing the tamponading agent from passing into the lumen. More specifically, the membrane is punctured by a surgeon using a laser once the tamponading agent is no longer present in the vitreous cavity.

[0105] The shunts and the method described hereinabove are effective in treating glaucoma in a patient by allowing for drainage for excess aqueous fluid from the ocular chambers into the orbital subarachnoid space during and after vitreoretinal surgery involving the use of a gas or oil tamponading agent.