EXPANDABLE FLUID DRAINAGE IMPLANTS AND ASSOCIATED DELIVERY DEVICES AND METHODS

A drainage implant is provided for the drainage of aqueous humor. The implant may comprise a collector, a connector and disperser. The collector and/or disperser may be self-expandable and can be held in an unexpanded condition by a delivery device. When positioned for implantation, the collector and disperser are ejected from the delivery device, whereby upon being ejected from the delivery device they can expand to a pre-defined final shape in the desired place. A delivery device for implanting the implant may have a shaft for accommodating the implant and a cutting edge that may be used to create a pocket or reservoir in the tissue where the implant device is to be implanted. Methods of implanting an implant are also disclosed.

DETAILED DESCRIPTION

Certain embodiments of devices and methods of using them are described herein with reference to the accompanying drawings. These embodiments are only examples, as numerous variations of the invention disclosed herein are possible within the scope of the appended claims.

FIG. 1Ashows a top view of an implant device11, andFIG. 1Bshows a side view of the same implant device11. The implant device11is formed of a tube made of a suitable flexible material that allows the implant device to be compressed to a low profile in a constrained condition and that allows the implant device to self-expand to an expanded profile when unconstrained. For example, the material may be a shape memory material, such as nitinol or another suitable shape memory alloy, or another suitable flexible material such as a suitable plastic or other metal. The cross-section of the tube may be circular, elliptical, rectangular or any other suitable shape.

In the unconstrained or “remembered” or expanded shape, the implant device11has the shape shown inFIGS. 1A and 1B. As shown in these figures, the implant device11comprises a spiral collector12and a conical helix disperser14connected by a connector16.

As can be seen inFIGS. 1A and 1B, the collector12has holes or slits13in the wall of the tube. These holes or slits13allow fluid to enter the tube at the collector12, together with the tube's natural hollow profile.

The connector16is formed of the portion of the tube of the implant device11between the collector12and the disperser14. In the embodiment shown inFIGS. 1A and 1B, there are no holes or slits in the connector16. In alternative embodiments, one or more holes or slits may be provided in the connector16. When the connector16is positioned in the Schlemm's Canal (as described below), the provision of one or more holes or slits can allow the drainage of aqueous humor directly into the Schlemm's Canal.

The expanded disperser14has a conical helix shape that can be seen inFIGS. 1A and 1B. The disperser14has holes or slits15in the wall of the tube. These holes or slits15allow fluid to exit the tube at the disperser14, together with the tube's natural hollow profile.

The implant device11ofFIGS. 1A and 1Bmay be implanted in an eye to facilitate drainage of aqueous humor in order to regulate IOP. In one example positioning, the implant device11is implanted at the area of the anterior chamber angle. When implanted, the collector12is placed in the anterior chamber against the inside surface of the sclera, near the Schlemm's Canal, the disperser14is placed in a pocket formed in the sclera (as described below), and the connector16extends between and connects the collector12and the disperser14. When the implant device11is implanted, the fluid flows from the high pressure area in the anterior chamber to the reservoir in the sclera, which has a lower pressure. The fluid enters the tube of the implant device11through the holes or slits13in the collector12. The fluid flows from the collector12through the connector16to the disperser14. The fluid then exits the tube of the implant device11through the holes or slits15in the disperser14. The wide shape of the disperser14directs the fluid widely within the pocket.

The spiral or helical shape of the collector and disperser acts as an anchor and reduces the ability of the device to migrate. The collector12anchors the device11to prevent it from moving into the sclera. The disperser14anchors the device to prevent it from moving into the anterior chamber. The height, width and depth of the disperser14keep the walls of the pocket away from each other, ensuring long-lasting functioning of the reservoir.

FIG. 2shows a schematic view of another implant device21comprising an expandable spiral collector22and an expandable conical helix disperser24. Like the implant device11, the implant device21may be formed of a tube made of a suitable flexible material as described above. The cross-section of the tube may be circular, elliptical or any other suitable shape.FIG. 2shows the implant device21in the expanded or unconstrained (“remembered”) shape. As with the implant device11, the collector22and the disperser24have holes or slits23,25in the wall of the tube. Holes or slits may also be provided in the connector26.

FIG. 3illustrates an example implantation location for an implant device. The implant device11, the implant device21, and the other implant devices described and illustrated herein may be implanted in the same location as that illustrated inFIG. 3. The eye includes the cornea1, conjunctiva2, sclera3, ciliary muscle4, anterior chamber5, iris6, posterior chamber7, vitreous8, lens9, and collector vessels/channels10. In this example positioning, the implant device21is shown as an example. The implant device is implanted at the area of the anterior chamber angle. When implanted, the collector22is placed in the anterior chamber5against the inside surface of the sclera3, near the Schlemm's Canal, the disperser24is placed in a pocket formed in the sclera3, and the connector26extends between and connects the collector22and the disperser24. When the implant device is implanted, the fluid flows from the high pressure area in the anterior chamber5to the reservoir in the sclera3, which has a lower pressure. The fluid enters the tube of the implant device21through the holes or slits23in the collector22. The fluid flows from the collector22through the connector26to the disperser24. The fluid then exits the tube of the implant device21through the holes or slits25in the disperser24. The wide shape of the disperser24directs the fluid widely within the pocket.

FIG. 4Ashows a delivery device40for implanting an implant device as described and illustrated herein. The delivery device40comprises a hollow shaft41having an internal lumen42, a sharp cutting edge43at the distal end of the hollow shaft41, and an illuminator44, such as a fiber optic tip.FIG. 4Bshows a view inside a part of the hollow shaft41of the delivery device40ofFIG. 4A, with an implant device11positioned inside the lumen42of the hollow shaft41. The implant device11is positioned inside the lumen42distal to (i.e., closer to the outlet than) an injector45, which is also positioned inside the lumen42of the hollow shaft41. In addition to being used for retaining the implant device during the implantation procedure, the hollow shaft41may be used for irrigation, aspiration and/or delivery of viscoelastic material (as described below). Additional lumens may be provided for these or other purposes. The cutting edge43may be provided, for example, by a crescent blade at the distal end of the delivery device40. More than one illuminator44or fiber optic may be used, which can improve visualization and orientation. The delivery device40may include a pressure probe for monitoring the IOP in real time.

As can be appreciated fromFIG. 4B, when the implant device11(or another similar implant device as described herein) is loaded into the lumen42of the delivery device40, the implant device11is held by the delivery device40in a low-profile, constrained condition. For example, when loaded in a lumen42of a delivery device40, the implant device11is straightened into a substantially straight shape. In the example ofFIG. 4B, the portion of the implant11that is adjacent the distal end of the injector45is the substantially straightened collector12. Because of its shape memory characteristics, the implant can be temporarily deformed into a low-profile shape for loading into the delivery device and for delivery to the implantation site. The shaft of the delivery device holds and maintains the implant in its low-profile configuration during delivery of the implant. When the implant is ejected from the delivery device, it self-expands to its unconstrained, relaxed or “remembered” shape.

FIG. 4Cshows another embodiment of a delivery device for implanting an implant device as described and illustrated herein.FIG. 4Cshows a delivery device40A comprising a shaft41A and a sharp cutting edge43A at the distal end of the shaft41A. As shown inFIG. 4C, an implant device11is positioned on the outside of the shaft41A, with the shaft41A passing through the internal lumen of the implant device11. The implant device11is positioned on the shaft41A distal to (i.e., closer to the ejection end than) an injector45A, which is also positioned on the outside of the shaft41A.

As can be appreciated fromFIG. 4C, when the implant device11(or another similar implant device as described herein) is loaded onto the shaft41A of the delivery device40A, the implant device11is held and maintained by the delivery device40A in a constrained, low-profile condition. For example, when loaded onto the shaft41A of a delivery device40A, the implant device11is straightened into a substantially straight shape, and held and maintained in that position by the shaft41A passing through the internal lumen of the implant device. The shaft41A is more rigid than the implant device11, and the shaft41A is sufficiently rigid to maintain the implant device11in its constrained low-profile configuration. In the example ofFIG. 4C, the portion of the implant11that is adjacent the distal end of the injector45A is the substantially straightened collector12. Because of its shape memory characteristics, the implant can be temporarily deformed into a low-profile shape for loading onto the delivery device and for delivery to the implantation site. The shaft of the delivery device holds and maintains the implant in its low-profile configuration during delivery of the implant. When the implant is ejected from the delivery device, by the injector45A being moved distally on the shaft41A and/or by the shaft41A being withdrawn proximally relative to the injector45A, the implant self-expands to its unconstrained, relaxed or “remembered” shape.

In addition to being used for retaining the implant device during the implantation procedure, the shaft41A may be hollow and may be used for irrigation, aspiration and/or delivery of viscoelastic material. Additional lumens may be provided for these or other purposes. The cutting edge43A may be provided, for example, by a crescent blade at the distal end of the delivery device40A. An illuminator may be used, similar to illuminator44. The delivery device40A may include a pressure probe for monitoring the IOP in real time.

As can be appreciated, the slits or other openings in the expandable portion(s) of the implant can increase the flexibility of the implant so that it can be better accommodated in or on the shaft of the delivery device. The slits or openings may be formed and positioned to assist in flexibility. A single slit or opening may be used, such as a single helical slit along the whole tube.

FIGS. 5A-5Gshow steps in an ab-interno implantation procedure, using a delivery device like the delivery device40shown inFIGS. 4A-B. First, the implant is loaded into the lumen of the delivery device40so that it is held in its constrained position. In this way, the expandable portion(s) of the implant can be delivered to the appropriate position with minimal tissue disruption. If a delivery device like the delivery device40A shown inFIG. 4Cis used, the implant is loaded onto the shaft41A of the delivery device40A so that it is held in its constrained position, thereby similarly allowing the expandable portion(s) of the implant to be delivered to the appropriate position with minimal tissue disruption. Then, as is known in the art for ab-interno procedures, the delivery device40or40A is advanced through an incision in the cornea1into the anterior chamber5at a position opposite the intended implantation site. Then, as shown inFIG. 5A, the delivery device40or40A is passed across the anterior chamber5to the angle between the cornea1and the iris6.

At the intended implantation site, as shown inFIG. 5B, the cutting edge43or43A of the delivery device40or40A is advanced into the tissue. The cutting edge43or43A is advanced into a sub-scleral space within the sclera3. The cutting edge43or43A may first penetrate the tissue in the Schlemm's Canal and then further into the sub-scleral space. Because the shaft41or41A of the delivery device40or40A has a low profile, and because the implant device is held at a low profile by the delivery device40or40A when passing from the anterior chamber to the desired position, tissue disruption is minimized.

When the cutting edge43or43A reaches the desired position in the sub-scleral space, the cutting edge43or43A may be used, as shown inFIG. 5C, to form a pocket50within the sclera3. The cutting edge43or43A allows the physician to create a wide and long pocket50in the sclera3that will later serve as a reservoir. The illuminator44helps the physician to see where the cutting edge43or43A is located and to make an accurate cut. The illuminated tip of the cutting edge43or43A is visible through the conjunctiva2and the sclera3.

The pocket50may be formed by moving the cutting edge43or43A generally parallel to the sclera until desired shape and size is achieved. The cutting edge43or43A may be advanced in different directions, as represented by the arrows inFIG. 5C. In one example of forming a pocket50, a 1 mm to 2 mm outside diameter crescent sharp edge43or43A may be moved to create a pocket that is 2 mm to 4 mm wide and 2 mm to 4 mm long. In another example, a pocket is created that is 6 mm wide and 6 mm long. Other dimensions are of course possible.

Through the hollow shaft41or41A (if hollow), it is possible to inject viscoelastic material in order to keep the pocket50formed and to reduce the flow of aqueous humor following the procedure. This may reduce the risk of overflow post-operation. In addition, saline may be injected through the hollow shaft to elevate the roof of the pocket50during the implantation process. Thus, an intra-scleral bleb may be formed. In addition, aspiration of tissue particles cut away by the cutting edge43or43A or aspiration of fluids may be carried out through the hollow shaft. The hollow shaft also may be used for irrigation purposes.

Once the pocket50is formed, the disperser24is ejected into the pocket50. This is performed by holding the position of the hollow shaft41of the delivery device40while advancing the injector45within the hollow shaft41. If the delivery device40A is used, this is performed by holding the position of the shaft41A of the delivery device40A while advancing the injector45A on the outside of the shaft41A. The injector45or45A pushes against the implant device, ejecting the portion of the implant device loaded toward the distal-most end of the lumen42or shaft41A. In this embodiment, the implant device is loaded with the disperser24toward the distal-most end of the lumen42or shaft41A and with the collector22toward the injector45or45A. At this stage, the injector45or45A is advanced only far enough to eject the disperser24portion of the implant device. When the disperser24is ejected from the lumen42or shaft41A of the delivery device40or40A, it self-expands to its unconstrained, pre-defined shape within the pocket50. If desired, the unconstrained disperser may be slightly larger than the created pocket, thereby creating some constant pocket-stretching force.FIG. 5Dshows the disperser24being ejected from the lumen42of the shaft41of the delivery device40, whereupon the disperser24expands into its pre-defined final shape within the pocket50in the sclera3.

Once the disperser24is in place in the pocket50, the delivery device40is withdrawn. As it is being withdrawn, the injector45is used to eject the connector portion26of the implant device from the lumen42of the shaft41of the delivery device40. This is shown inFIG. 5E. If the delivery device40A is used, as the shaft41A is withdrawn, the injector45A is used to eject the connector portion26of the implant device from the outside of the shaft41A of the delivery device40A.

Once the delivery device40or40A has been withdrawn to the point that the distal end of the lumen42of the shaft41or the distal end of the shaft41A is in the anterior chamber5, as shown inFIG. 5E, the injector45or45A is used to eject the collector22. As before, in the case of the delivery device40, this is performed by holding the position of the hollow shaft41of the delivery device40while advancing the injector45within the hollow shaft41. In the case of the delivery device40A, this is performed by holding the position of the shaft41A of the delivery device40A while advancing the injector45A over the shaft41A. The injector45or45A pushes against the implant device, ejecting the collector22, whereupon the collector22expands to its pre-defined final shape in the desired place.FIG. 5Fshows the collector22being ejected from the lumen42of the delivery device40, whereupon it expands in the anterior chamber5to anchor the implant device.

Once the implant is in place, the delivery device40or40A is withdrawn from the eye.FIG. 5Gshows the implant21in place after the delivery device40or40A has been withdrawn. In can be appreciated that in this ab-interno procedure, at the area of the implantation, the conjunctiva2remains intact. In such a procedure where the pocket50is formed beneath the outer surface of the sclera3, the outer surface of the sclera3also remains intact. The ability to keep the conjunctiva2and in certain embodiments also the outer surface of the sclera3intact can help achieve a positive clinical outcome.

Alternatives to the above-described procedure are possible. In one alternative, the pocket50is formed to connect to the subconjunctival space between the conjunctiva2and the sclera3. The pocket50may be formed to reach the subconjunctival space, or one or more channels may be formed connecting the pocket50to the subconjunctival space. This facilitates the flow of aqueous humor from the implant device into the subconjunctival space. This may be utilized, for example, when an additional filtering mechanism is needed. As one example, it is possible to facilitate flow into the sub-conjunctival space by performing the following steps. First, saline, lidocaine, viscoelastic material, or another suitable material is injected between the sclera3and the conjunctiva2, which results in elevating the tissue of the conjunctiva2away from the sclera3, thereby forming a space between the sclera3and the conjunctiva2. This reduces the risk of harming the conjunctiva2during subsequent cutting of the pocket50. After the conjunctiva2is raised, a connection is made between the pocket50and the subconjunctival space. This may be done, for example, using the cutting edge43or43A.

FIG. 5Hshows this alternative, in which the cutting edge43or43A is used to form the pocket50near the outer surface of the sclera3, and the cutting edge43or43A is used to cut a connection channel through the sclera3to the subconjunctival space, thereby connecting the pocket50with the space between the sclera3and the conjunctiva2. Thus, aqueous humor can flow through the implant device from the anterior chamber5to the sub-conjunctival filtering space. In one example, the disperser of the implant device is implanted to lie completely within the sclera3, permitting flow from there to the subconjunctival space. In other examples, the disperser of the implant device is implanted to lie only partially within the sclera3, or in an area between the conjunctiva2and the sclera3, such that the disperser can output the aqueous humor, in whole or in part, directly into the subconjunctival space.

It will be appreciated that the views shown herein are schematic representations and that, for example, the pocket50may take various forms. For example, the pocket50may be cut to have its largest dimensions generally parallel to the sclera3or only at a slight angle to the sclera3.FIG. 5Ishows a line52representing an example of a direction in which the cutting edge43is directed through the sclera3. The pocket50may be formed along this line52.

In another alternative, an ab-externo implantation method is used. In an example of an ab-externo method, the physician first cuts the conjunctiva, then forms the intra-scleral pocket. In this procedure, the pocket may be formed in a similar manner as current deep sclerectomy procedures. Alternatively, a delivery device with crescent blade as described above may be used to form the intra-scleral pocket. Once the pocket is formed, the delivery device with the implant inside or mounted on the shaft is advanced through the pocket into the anterior chamber, whereupon the collector is released in the same manner as described above, resulting in its self-expansion. In this embodiment, the implant is loaded with the collector toward the distal-most end of the lumen or shaft of the delivery device and with the disperser toward the injector. Once the collector is ejected, the delivery device is withdrawn back to the pocket, during which time the connector is released. Then, when the distal end of the lumen or shaft of the delivery device has reached the pocket, the disperser is released in the pocket, resulting in the self-expansion of the disperser. Then the delivery device is withdrawn from the eye. The sclera is closed, and the conjunctiva is closed. Sutures may be used to keep the sclera and/or conjunctiva closed.

After any of the above-described procedures, further implants may be implanted. When it is desired to implant multiple implants, the delivery device can be loaded with multiple implants so that successive implants can be implanted without having to completely withdraw the delivery device.

FIG. 6shows an alternative implant design. The implant device61comprises an expandable fish-tail collector62and an expandable spiral disperser64connected by a connector66. The implant device61is made of a flexible tube, as in the above embodiments, except that the tube is bifurcated to form the fish-tail collector62. The tube has slits and/or holes as described above. The implant device61may be implanted using a delivery device as described above and in a similar manner as described above.

FIG. 7shows another alternative implant design. The implant device71comprises an expandable fish-tail collector72and a disperser74in the form of an expandable set of fingers77. The collector72and disperser74are connected by a connector76. The implant device71is made of a flexible tube, as in the above embodiments, except that the tube is bifurcated to form the fish-tail collector72and branches out into a plurality of tubes to form the set of fingers77. The tube has slits and/or holes as described above, and each finger77may be a tube with additional holes and/or slits. The multiple fingers77insure continuous flow should one of them become clogged. The implant device71may be implanted using a delivery device as described above and in a similar manner as described above. In one embodiment, the fingers77may be used to disperse the aqueous humor toward the collector vessels10.

FIGS. 8A-8Dshow another alternative implant design.FIG. 8Ashows a top view,FIG. 8Bshows an end view, andFIG. 8Cshows a side view of the implant device81in the constrained configuration.FIG. 8Dshows a side view of the implant device81in the unconstrained, expanded configuration. The implant device81comprises a tube with cuts89in the side of the tube to form the collector and disperser. The cuts89can result in the collector and/or disperser having one, two, or more than two expandable side arms. In the illustrated embodiment, at one end, the cuts89result in two expandable side arms83forming the collector82, and, at the other end, the cuts89result in two expandable side arms85forming the disperser84. Uncut portions of the tube form the connector86, an end87of the collector82, and an end88of the disperser84. The implant device81may be implanted using a delivery device as described above and in a similar manner as described above. In the constrained condition within the lumen of the delivery device, the expandable side arms83,85are held in, so that the implant device81has a low profile generally as shown inFIGS. 8A-8C. When the implant device81is ejected from the lumen of the delivery device, the release of the implant device81from the constraint of the delivery device allows the expandable side arms83,85to expand to their expanded condition, as shown inFIG. 8D. In this manner, the expanded collector82and disperser84perform similar functions as described above with respect to other implants.

FIG. 8Eshows an alternative implant design comprising a collector similar to that inFIGS. 8A-8Dand a disperser similar to that inFIGS. 1A-1B.FIG. 8Eshows the implant device81A in the unconstrained, expanded configuration. On one end, the implant device81A comprises a tube with cuts89A in the side of the tube to form the collector82A. As indicted above with respect toFIGS. 8A-8D, the cuts89A can result in the collector having one, two, or more than two expandable side arms. In the illustrated embodiment, the cuts89A result in four expandable side arms83A forming the collector82A. Uncut portions of the tube form the connector86A and an end87A of the collector82A. At the other end, the implant device81A comprises a disperser14A similar to that inFIGS. 1A-1B, having holes or slits15A in the wall of the tube. The implant device81A may be implanted using a delivery device as described above and in a similar manner as described above. In the constrained condition, the expandable side arms83A are held in, and the disperser14A is substantially straightened, so that the implant device81A has a low profile. When the implant device81A is ejected from the delivery device, the release of the implant device81A from the constraint of the delivery device allows the expandable side arms83A and the disperser14A to expand to their expanded conditions. In this manner, the expanded collector82A and disperser14A perform similar functions as described above with respect to other implants. In other embodiments, the collector and disperser geometries may be reversed.

FIGS. 9A and 9Bshow another alternative implant design.FIG. 9Ashows an implant device91comprising a collector92with an expandable frame and a disperser94with an expandable frame. The collector92and disperser94are connected by a connector96.FIG. 9Bshows the implant device91ofFIG. 9Aloaded inside a lumen42of shaft41of a delivery device40. The frame97of the implant device91may be a wire or tube made of a suitable flexible material, such as nitinol or another material, as described above. Areas within the frame97may be coated or covered, in whole or in part, by a suitable coating or covering98, for example a mesh of PVDF. The coating or covering can be made from biological or artificial material, can be degradable or stable, and can be made from solid or perforated material. In the area of the disperser94, the covering98can help keep the pocket shape intact. When a mesh is used, the covering98provides additional flow paths through the mesh. The implant device91may be implanted using a delivery device as described above and in a similar manner as described above. For delivery, the flexible implant device91is rolled into a low profile and loaded into a lumen42of a delivery device. As the portions of the implant device91are ejected from the lumen42, they unroll to their unconstrained configuration as shown inFIG. 9A.

FIG. 10shows another version of an implant device101comprising a collector102, a connector106, and a disperser104having an expandable frame. The frame107in this example is a tube made of a suitable flexible material as described above. Holes or slits109are formed in the tube. Areas within the frame107may be coated or covered, in whole or in part, by a suitable coating or covering108, as described above. In the area of the disperser104, the covering108can help keep the pocket shape intact. When a mesh is used, the covering108provides additional flow paths through the mesh. The implant device101may be implanted using a delivery device as described above and in a similar manner as described above. The implant device101may be rolled or compressed for loading into the lumen of a delivery device.

FIG. 11shows another alternative implant design. The implant device111comprises an expandable fish-tail collector112and a disperser114in the form of an expandable set of fingers117. The collector112and disperser114are connected by a connector116. The implant device111is made of a flexible tube, as in the above embodiments, except that the tube is bifurcated to form the fish-tail collector112and branches out into a plurality of tube parts to form the set of fingers117. The tube may have one or more slits and/or holes as described above, and each finger117may be a tube with additional holes and/or slits. The multiple fingers117may be cut and shaped from the same original tube as that used to form the connector116and collector112. The multiple fingers117insure continuous flow should one or more of them become clogged. The implant device111may be implanted using a delivery device as described above and in a similar manner as described above. In one embodiment, the fingers117may be used to disperse the aqueous humor toward the collector vessels10.

Other variations of the above described implants are possible. The expandable collector and/or disperser may be in the shape of a spiral, a conical helix, a fish tail, a set of fingers, a set of arms, a frame, a dish, or any other suitable expandable shape. A conical helix, as opposed to a flat spiral, when used as the disperser, can help separate the top and bottom of the pocket and provide a large reservoir that is less susceptible to becoming closed. Other shapes (e.g., extending fingers, conical shapes, etc.) also can serve this purpose. Any of these shapes may be provided with slits and/or holes to improve collection of fluid and reduce the chance of obstruction. Different sizes of slits and/or holes may be used. In some instances, it may be desired that the disperser have only small openings or no openings close to the connector, in order to divert the flow of fluid far from the connector. Anchors such as barbs or hooks may be provided on the implant to prevent migration.

In some embodiments, only one of the disperser or collector may be expandable. For example, for use with an ab-externo implantation procedure, the collector may be expandable, while the disperser may be rigid or semi-rigid. In other embodiments, an implant having a configuration generally as described herein may be rigid or semi-rigid.

The implant device may be provided with features for controlling fluid flow. For example, when a tube is used, the inside of the tube may be provided with an impediment that provides resistance to reduce flow rate. Alternatively, a valve may be positioned in the tube for regulating fluid flow. The valve may open and close, and let in more or less flow, based on pressure fluctuation or based on control by an actuator. Additionally, actuators may open and close holes in the implant, for example in the disperser, to increase or decrease the flow in certain areas.

An implant device as described herein may also incorporate other features. For example, it may carry a pressure sensor, flow sensor or flow meter.

Based on the above description and the accompanying drawings, the principles and operation of the invention, as well as how to make and use the invention, can be understood by persons of ordinary skill in the art. Many embodiments and variations are possible that take advantage of the principles and operation of the invention described herein. The examples described herein and shown in the accompanying drawings are meant as examples only and are not intended to be limiting of the scope of the invention defined by the appended claims.