DESC:FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(Section 10 and Rule 13)

1. TITLE OF THE INVENTION:
OPHTHALMIC STENT, DELIVERY SYSTEM AND METHODS THEREOF
2. APPLICANT:
Meril Corporation (I) Private Limited, an Indian company of the address Survey No. 135/139, Muktanand Marg, Bilakhia House, Pardi, Vapi, Valsad-396191 Gujarat, India.

The following specification particularly describes the invention and the manner in which it is to be performed:

FIELD OF INVENTION
[001] The present disclosure relates to a medical device. More particularly, the present disclosure relates to an ophthalmic stent, its delivery system and methods thereof.
BACKGROUND OF INVENTION
[002] A human eye is a substantially circular shaped organ that helps a healthy individual to see the world around. The eye contains a cornea at the anterior end and a retina at the posterior end. A lens connected to ciliary muscles is disposed between the cornea and the retina. The cornea allows the light to enter the eye, the lens dynamically adjust focal length and a picture is formed on the surface of the retina. The retina is provided with a plurality of optical nerves that helps to perceive the picture formed on the surface of the retina.
[003] The space between the lens and the cornea is filled with aqueous humor (AH). A healthy eye constantly produces a small amount of AH while an equal amount of AH flows out through a trabecular meshwork (TM) and into the blood circulation (via the Schlemm’s canal) of the body. Thus, the regulation of production and outflow (drainage) of the aqueous humor (AH) within the eye maintains a fluid pressure in the eye, also known as intraocular pressure (IOP). However, if AH fails to drain into the Schlemm canal due to blockage of the TM, the increase in the volume of AH due to constant production of AH leads to an increase in the IOP.
[004] Glaucoma is a disorder of the eye that is the leading cause of irreversible blindness worldwide. The most common form of Glaucoma is a primary open-angle glaucoma (POAG) where the IOP increases due to blockage of the TM. Glaucoma, in the early stages, progresses without any noticeable symptoms. And, at advanced stages due to persistent increase in IOP, symptoms of peripheral vision loss, become apparent. The increase in IOP is detrimental to the optic nerves of the eye. After its onset, Glaucoma cannot be cured permanently. However, with early detection, Glaucoma can be managed to slow its progression.
[005] Traditional treatments for Glaucoma, particularly for individuals undergoing cataract surgery or those with mild to moderate POAG, include medication (such as eye drops to lower the IOP), laser therapy, or surgery, depending on the type and severity of the condition. However, for many individuals, medications alone may not lead to adequate IOP control. For such individuals, a minimally invasive glaucoma surgery (MIGS) is used to implant a micro-stent and create an artificial drainage pathway for the AH through the TM. The micro-stent also helps to reduce dependence on the medications to control IOP.
[006] However, conventional micro-stents suffer from a few drawbacks. For instance, conventional micro-stents include sharp edges that damage the TM and the Schlemm’s canal. Further, over time, the conventional micro-stents are known to loosen and migrate from the site of implantation, thereby failing to provide long term control of IOP.
[007] Furthermore, a delivery system used to implant the micro-stent does not allow the micro-stent to be resheathed/recaptured. The conventional delivery system implants the micro-stent by pushing the micro-stent across the TM. Hence, there is a risk that due to excessive pushing force applied on the conventional micro-stent, the micro-stent may be pushed beyond the TM and into the Schlemm’s canal, thus creating medical complications (for example, tissue damage, blockage, etc.). Implantation of the micro-stent beyond the TM is termed as deep implantation.
[008] Therefore, there arises a need for an improved stent, a delivery system and methods thereof that overcomes the drawbacks of associated with the conventional solutions.
SUMMARY OF INVENTION
[009] Particular embodiments of the present disclosure are described herein below with reference to the accompanying drawings, however, it is to be understood that the disclosed embodiments are mere examples of the disclosure, which may be embodied in various forms. Well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure.
[0010] In an exemplary embodiment, the present disclosure relates to an ophthalmic stent having a proximal end and a distal end. The ophthalmic stent includes two peripheral portions, and a middle portion. The two peripheral portions are disposed at the proximal end and the distal end respectively. Each of the two peripheral portions define a ring-shaped body having a central hole. The ring-shaped body includes a pre-defined height ranging from 0.09 mm to 0.11 mm. The ring-shaped body includes a plurality of rows of first closed cells arranged circumferentially. The middle portion is coupled between the holes of the two peripheral portions. The middle portion defines a lumen. At least an end segment of the middle portion towards the proximal end and the distal end is encircled by respective ring-shaped body of respective peripheral portion. The middle portion defines a plurality of rows of second closed cells arranged circumferentially. The two peripheral portions and the middle portion are braided with a plurality of monofilaments having shape memory properties.
[0011] In another exemplary embodiment, the present disclosure relates to a delivery system including a proximal end and a distal end. A handle is disposed at the proximal end and includes a knob. An outer sheath defines a lumen and is coupled to a distal end of the handle. A pusher defines a lumen and is movably disposed within the lumen of the outer sheath. The pusher is being operationally coupled to the knob. The pusher includes a bumper disposed at its distal end. A needle includes a tabbed portion and is movably disposed within the lumen of the pusher. The needle is operationally coupled to the knob. The knob, upon rotation in a pre-defined direction, is configured to simultaneously push the pusher towards the distal end and pull the needle towards the proximal end.
[0012] In yet another exemplary embodiment, the present disclosure relates to an assembly including an ophthalmic stent as described above and a delivery system as described above. The ophthalmic stent is configured to be mounted in a radially collapsed state on a needle between a tabbed portion and on a bumper of the delivery system.
BRIEF DESCRIPTION OF DRAWINGS
[0013] The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the apportioned drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the disclosure is not limited to specific methods and instrumentality disclosed herein. Moreover, those in the art will understand that the drawings are not to scale.
[0014] Fig. 1 depicts a stent 100 deployed across the trabecular meshwork of an eye according to an embodiment of the present disclosure.
[0015] Fig. 2 depicts the stent 100 according to an embodiment of the present disclosure.
[0016] Fig. 2a depicts a top view of the stent 100 according to an embodiment of the present disclosure.
[0017] Fig. 2b depicts an axial cross-sectional view of the stent 100 according to an embodiment of the present disclosure.
[0018] Fig. 2c depicts an underside view of a peripheral portion 111 of the stent 100 according to an embodiment of the present disclosure.
[0019] Fig. 3 depicts a method 300 to manufacture the stent 100, according to an embodiment of the present disclosure.
[0020] Figs. 3a-3c depict a mold 350 used to manufacture the stent 100, according to an embodiment of the present disclosure.
[0021] Fig. 4 depicts an exemplary delivery system 400, according to an embodiment of the present disclosure.
[0022] Figs. 4a, 4b and 4b1 depict enlarged portions of sub-assemblies of the delivery system 400 as depicted in Fig. 4, according to an embodiment of the present disclosure.
[0023] Fig. 4c depicts a handle 410 of the delivery system 400, according to an embodiment of the present disclosure.
[0024] Fig. 4d depicts a pusher 450 of the delivery system 400, according to an embodiment of the present disclosure.
[0025] Fig. 4e depicts a needle 470 of the delivery system 400, according to an embodiment of the present disclosure.
[0026] Fig. 5 depicts a method 500 to deploy the stent 100 using the delivery system 400 according to an embodiment of the present disclosure.
[0027] Fig. 5a depicts an assembly of a radially compressed state of the stent 100 and the delivery system 400 according to an embodiment of the present disclosure.
[0028] Figs. 5b and 5c depict an assembly of a partially expanded state of the stent 100 and the delivery system 400 according to an embodiment of the present disclosure.
[0029] Fig. 5d depicts an assembly of a radially expanded state of the stent 100 and the delivery system 400 according to an embodiment of the present disclosure.
DETAILED DESCRIPTION OF THE ACCOMPANYING INVENTION
[0030] Prior to describing the invention in detail, definitions of certain words or phrases used throughout this patent document will be defined: the terms "include" and "comprise", as well as derivatives thereof, mean inclusion without limitation; the term "or" is inclusive, meaning and/or; the phrases "coupled with" and "associated therewith", as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have a property of, or the like. Definitions of certain words and phrases are provided throughout this patent document, and those of ordinary skill in the art will understand that such definitions apply in many, if not most, instances to prior as well as future uses of such defined words and phrases.
[0031] Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment, but mean “one or more but not all embodiments” unless expressly specified otherwise. The terms “including,” “comprising,” “having,” and variations thereof mean “including but not limited to” unless expressly specified otherwise. An enumerated listing of items does not imply that any or all of the items are mutually exclusive and/or mutually inclusive, unless expressly specified otherwise. The terms “a,” “an,” and “the” also refer to “one or more” unless expressly specified otherwise.
[0032] Although the operations of exemplary embodiments of the disclosed method may be described in a particular, sequential order for convenient presentation, it should be understood that the disclosed embodiments can encompass an order of operations other than the particular, sequential order disclosed. For example, operations described sequentially may in some cases be rearranged or performed concurrently. Further, descriptions and disclosures provided in association with one particular embodiment are not limited to that embodiment, and may be applied to any embodiment disclosed herein. Moreover, for the sake of simplicity, the attached figures may not show the various ways in which the disclosed system, method, and apparatus can be used in combination with other systems, methods, and apparatuses.
[0033] Furthermore, the described features, advantages, and characteristics of the embodiments may be combined in any suitable manner. One skilled in the relevant art will recognize that the embodiments may be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments. These features and advantages of the embodiments will become more fully apparent from the following description and apportioned claims, or may be learned by the practice of embodiments as set forth hereinafter.
[0034] The present disclosure relates to an ophthalmic stent (or stent) and a method to deploy the stent using a delivery system. The stent is used to create an artificial drainage path in the eye to allow flow of fluids across a blocked structure, for example, flow of aqueous humor (AH) across a blocked/diseased trabecular meshwork (TM). By restoring the flow of AH across the blocked TM, the stent helps to control the intraocular pressure (IOP) and slows down the progressions of conditions like Glaucoma by preventing further damage to the optic nerves due to increased IOP.
[0035] Until and unless stated explicitly, the stent and the parameters/properties thereof disclosed in the present disclosure are with reference to a radially expanded state of the stent.
[0036] The stent of the present disclosure enables an individual to reduce their reliance on frequent dosage of medication to manage IOP. The shape and structure of the stent prevent any risk of loosening, dislodgement and migration of the stent once the stent is deployed. In an embodiment, the stent includes smooth, round and flexible edges which prevents infliction of any trauma to the surrounding tissue after the stent is deployed.
[0037] The delivery system of the present disclosure enables the stent to be easily deployed across the TM via a minimally invasive method. The delivery system allows a medical practitioner to resheath the stent, if required. For example, the medical practitioner may resheath the stent to reposition the stent during deployment of the stent. The delivery system enables smooth deployment of the implant without requiring the medical practitioner to thrust forward the implant and/or the delivery system, to deploy the stent. Accordingly, the risk of deep implantation of the stent is minimized.
[0038] Now referring to the figures, Fig. 1 depicts an exemplary stent 100 of the present disclosure deployed across the trabecular meshwork 10. The trabecular meshwork 10 separates the anterior chamber 11 of the eye (not shown) and the Schlemm’s canal 13. In a healthy individual, the trabecular meshwork 10 allows the AH present in the anterior chamber 11 to drain into the Schlemm’s canal 13 to control IOP. In diseased or blocked condition, the trabecular meshwork 10 fails to allow the AH to pass through thereby increasing the IOP of the anterior chamber 11. The stent 100 creates an artificial pathway for the AH to pass across the diseased/blocked trabecular meshwork 10 from the anterior chamber 11 to the Schlemm’s canal 13, thereby preventing the IOP to increase uncontrollably. The stent 100 has a proximal end 100a and a distal end 100b. The proximal end 100a of the stent 100 is deployed in the anterior chamber 11 of the eye. The distal end 100b of the stent 100 is deployed in the Schlemm’s canal 13 of the eye.
[0039] Fig. 2 depicts a perspective view of the stent 100. The stent 100 has a tubular structure made by braiding a plurality of monofilaments to obtain a predefined braiding pattern. The number of monofilaments to be braided ranges from four to eight. In an exemplary embodiment, the stent 100 is made by braiding six monofilaments. The monofilament may have a lateral cross-sectional shape including, but not limited to, circular, square, triangle, hexagonal, octagonal, etc. In an exemplary embodiment, the lateral cross-sectional shape of the monofilament is circular. The monofilament has a pre-defined diameter ranging from 20 µm to 40 µm. In an exemplary embodiment, the diameter of the monofilament is 25 µm.
[0040] The monofilaments are made of one or more materials including but not limited to, nickel-titanium alloy (nitinol), elgiloy, cobalt-chromium (CoCr), stainless steel (medical grade), etc. In an exemplary embodiment, the monofilaments (and the stent 100) are made of nitinol. The material, with which the stent 100 is made, has shape-memory properties. Due to shape memory properties, the stent 100 is self-expandable from a radially compressed state (as shown in Fig. 5a) to a radially expanded state (as shown in Fig. 1). The radially compressed state of the stent 100 enables the stent 100 to be deployed using a minimally invasive deployment method. The radially expanded state helps the stent 100 to be deployed across the trabecular meshwork 10 without the risk of loosening, dislodgement and/or migration.
[0041] The plurality of monofilaments of the stent 100 are braided at a pre-defined braiding angle. The braiding angle corresponds to the angle defined by the intersection of two monofilaments to obtain the braiding pattern. The braiding angle ranges from 90° to 160°. In an exemplary embodiment, the braiding angle is 150°. The braiding angle of the stent 100 plays a crucial role in radially supporting the wall of trabecular meshwork 10 to maintain the patency of the artificial pathway created for the AH to pass across the diseased/blocked trabecular meshwork 10. Further, the braiding angle prevents tissue growth inside the stent 100 (for example, via fibrosis or obstruction) thereby preserving the function of the stent 100 for a long period of time.
[0042] The stent 100 includes a plurality of portions. In an exemplary embodiment, as shown in Fig. 2, the stent 100 includes two peripheral portions 111 and a middle portion 113. The peripheral portion 111, as the name suggest, is disposed at respective ends of the stent 100. In other words, one each of the peripheral portions 111 is disposed at the proximal end 100a and the distal end 100b. The middle portion 113 is disposed between the two peripheral portions 111 and defines a lumen 113a therein. The maximum length of the stent 100 ranges from 0.22 mm to 0.26 mm. In an exemplary embodiment, the maximum length of the stent 100 is 0.24 mm.
[0043] In an exemplary embodiment, the two peripheral portions 111 are structurally mirror images of each other. Alternately, one peripheral portion may be larger than the other. The two peripheral portions 111 at least partially abut the respective surface of the trabecular meshwork 10 thereby helping to secure the stent 100 thereon. For sake of brevity, only one of the peripheral portions 111 is described in detail. The description is equally applicable to both the peripheral portions 111 of the stent 100.
[0044] The top view of the peripheral portion 111 (and the stent 100) is depicted in Fig. 2a. The peripheral portion 111 defines a ring-shaped body having a central hole (or hole) 111a. The ring-shaped body has a pre-defined diameter ranging from 0.3 mm to 0.5 mm. The ring-shaped body of the two peripheral portions 111 of the stent 100 may have same or different diameter. In an exemplary embodiment, the pre-defined diameter of the ring-shaped body of the two peripheral portions 111 is the same, and is 0.4 mm. The ring-shaped body of the two peripheral portion 111 of the stent 100 has a pre-defined height ranging from 0.09 mm to 0.11 mm. The ring-shaped body of the two peripheral portions 111 of the stent 100 may have same or different height. In an exemplary embodiment, the height of the ring-shaped body of the two peripheral portions 111 is the same, and is 0.08 mm.
[0045] The hole 111a of the peripheral portion 111 is disposed at a center. The hole 111a is an extension of the lumen 113a of the middle portion 113. The hole 111a has a pre-defined diameter ranging from 0.14 mm to 0.16 mm. The holes 111a of the two peripheral portions 111 may have same or different diameter. In an exemplary embodiment, the diameter of the hole 111a of the two peripheral portions 111 is the same, and is 0.15 mm. The hole 111a allows the AH to either enter and exit the stent 100. In other words, the hole 111a of the peripheral portion 111 that is disposed within the anterior chamber 11 allows the AH to enter the stent 100. And, the hole 111a of the peripheral portion 111 that is disposed within the Schlemm’s canal 13 allows the AH to exit the stent 100.
[0046] As shown in Fig. 2b, the ring-shaped body of the peripheral portion 111 defines a vertical tapering edge (or edge) 111b that extends towards the middle portion 113 and at least partially bulges radially outward with a substantially curved profile. The radially outward curved profile of the edge 111b defines an angle ‘a’ with respect to a horizontal axis ‘x’. The angle ‘a’ ranges from 90° to 160°. The angle ‘a’ of the two peripheral portions 111 may be same or different. In an exemplary embodiment, the angle ‘a’ of the two peripheral portions 111 is the same, and is 130°. Due to the angle ‘a’, the edge 111b of the respective peripheral portions 111 at least partially abuts the respective surface of the trabecular meshwork 10 and flexibly provides a compressive force to firmly hold the trabecular meshwork 10 therebetween without any trauma to the surrounding tissues. The edges 111b prevent the risk of loosening, dislodgement and/or migration of the stent 100 after it is deployed across the trabecular meshwork 10. The substantially curved profile of the edge 111b prevents trauma to the surrounding tissue.
[0047] Fig. 2c depicts an underside view of the peripheral portion 111. A free-end 111c of the ring-shaped body defines a plurality of circumferentially extending crowns 111c1. Each crown 111c1 is coupled to the two adjacent crowns 111c1 disposed at respective sides. The number of crowns 111c1 depends upon the diameter of the peripheral portion 111 and/or the number of monofilaments used to make the stent 100. The number of crowns 111c1 ranges from four to eight. In an exemplary embodiment, the free-end 111c defines six crowns 111c1. The crowns 111c1 enable atraumatic deployment of the stent 100 across the trabecular meshwork 10.
[0048] As shown in Fig. 2c, the ring-shaped body of the peripheral portion 111 defines a plurality of rows of first closed cells 111d arranged circumferentially. The first closed cells 111d has a pre-defined shape including but not limited to diamond, rhombus, square, triangle, etc. In an exemplary embodiment, the shape of the first closed cells 111d is rhombus. The number of rows of first closed cells 111d depends upon the dimensions of the peripheral portion 111. The peripheral portion 111 includes at least three rows of first closed cells 111d. Each of the first closed cell 111d has a pre-defined area that increases from the hole 111a of the peripheral portion 111 to the a free-end 111c of the peripheral portion 111. A ratio between the area of the first closed cell 111d disposed adjacent the free-end 111c and the first closed cell 111d disposed adjacent the hole 111a ranges from 38:25 to 25:20. In an exemplary embodiment, the ratio is 40:27.
[0049] As shown in Fig. 2b, the middle portion 113 is coupled between the holes 111a of the two peripheral portions 111 of the stent 100, and extends therebetween. The middle portion 113 provides an artificial pathway to the AH to pass through the stent 100 and across the trabecular meshwork 10. The middle portion 113 also prevents the artificial pathway created by the stent 100 to collapse, thereby allowing the stent 100 to control IOP for years.
[0050] At least a segment of the middle portion 113 towards the proximal end 100a and the distal end 100b is at least partially encircled by respective ring-shaped body of the respective peripheral portion 111, namely end segments 113b. The end segments 113b of the middle portion 113 flanks a central segment 113c of the of the middle portion 113. In other words, the central segment 113c is disposed between the two end segments 113b. The central segment 113c is disposed across the trabecular meshwork 10 after the stent 100 is deployed.
[0051] The end segments 113b have a pre-defined height ranging from 0.07 mm to 0.09 mm. In an exemplary embodiment, the height of the end segment 113b is 0.08 mm. Each of the two end segments 113b may have a uniform diameter or a tapering diameter. If the diameter of the end segment 113b tapers, the diameter may taper gradually or abruptly. In an exemplary embodiment, as shown in Fig. 2b, the two end segments 113b are tapered having a diameter that gradually reduces from the hole 111a of the peripheral portion 111 to the central segment 113c of the middle portion 113. In other words, the diameter of the end segment 113b is maximum adjacent to the hole 111a and is minimum adjacent to the central segment 113c. Accordingly, the end segment 113b has a maximum diameter ranging from 0.14 mm to 0.16 mm and a minimum diameter ranging from 0.11 mm to 0.13 mm. In an exemplary embodiment, the maximum and minimum diameter of the end segment 113b are 0.15 mm and 0.12 mm respectively. The tapering diameter of the two end segments 113b serves as an anchor against the trabecular meshwork 10 to maintain the position of the stent 100 and prevents its migration into the Schlemm’s canal 13 after the stent 100 is deployed.
[0052] The central segment 113c has a pre-defined height ranging from 0.07 mm to 0.09mm. In an exemplary embodiment, the height of the central segment 113c is 0.08 mm. The diameter of the central segment 113c is corresponds to the minimum diameter of the end segments 113b. In an exemplary embodiment, the diameter of the central segment 113c is 0.12 mm.
[0053] As shown in Fig. 2c, the middle portion 113 defines a plurality of rows of second closed cells 113d arranged circumferentially. The second closed cells 113d has a pre-defined shape including but not limited to diamond, rhombus, square, triangle, etc. In an exemplary embodiment, the shape of the second closed cells 113d is diamond. The number of rows second closed cells 113d depends upon the dimensions of the middle portion 113. Each of the second closed cell 113d has a pre-defined area that increases from the central segment 113c of the middle portion 113 to the end segment 113b of the middle portion 113 (i.e., adjacent the hole 111a). A ratio between the area of the second closed cell 113d disposed adjacent the hole 111a and the second closed cell 113d disposed adjacent the central segment 113c ranges from 30:27 to 26:23. In an exemplary embodiment, the ratio is 28:25.
[0054] A ratio between the area of the second closed cells 113d disposed adjacent the central segment 113c and the area of the first closed cell 111d disposed adjacent the free-end 111c ranges from 9:6 to 7:4. In an exemplary embodiment, the ratio is 8:5.
[0055] Fig. 3 depicts an exemplary method 300 of making the stent 100 of the present disclosure. The method 300 commences at step 301 by forward braiding a plurality of monofilaments to obtain a first braided structure (not shown). The number of monofilaments ranges from four to eight. In an exemplary embodiment, six nitinol wires (i.e., the monofilaments) are braided in a forward direction to obtain the first braided structure. The forward direction corresponds to one end of the first braided structure to the other end of the first braided structure, for example, from the proximal end 100a to the distal end 100b.
[0056] In an exemplary embodiment, the nitinol wires are forward braided using an automatic braiding machine (MB-24A1WG/MB-32A1WG, procured from Dongguan Guanbo Precision Machinery CO., LTD) having carriers ranging from 12 pairs to 16 pairs depending on the size of the stent 100. Each pair of carriers define an angle ranging from 90° to 160° between them.
[0057] At step 303, the first braided structure obtained from step 301 is subjected to a primary shape setting process at a pre-defined temperature for a pre-defined time period. The pre-defined temperature ranges from 450 °C to 470 °C. The pre-defined time period ranges from 3 minutes to 5 minutes. In an exemplary embodiment, the first braided structure was subjected to a temperature of 470 °C for 3 minutes 30 sec. The primary shape setting process helps to impart strength to the stent 100.
[0058] At step 305, the plurality of monofilaments of the first braided structure are back braided to obtain a second braided structure (not shown). The back braiding of step 305 is same as that of step 301 except that the monofilaments are braided in a backward direction, for example, from the distal end 100b to the proximal end 100a. Back braiding may be done using the same machine as in step 301. In an exemplary embodiment, at the end of step 305, the braiding of the two peripheral portions 111 and the middle portion 113 with the plurality of monofilaments having shape memory properties is complete.
[0059] At step 307, the second braided structure obtained from step 305 is subjected to a molding procedure to obtain the stent 100. The molding procedure helps to define the plurality of portions of the stent 100 (as described above).
[0060] In an exemplary embodiment, the molding procedure is performed by attaching the second braided structure to a mold. The mold has a shape corresponding to the radially expanded state of the stent 100. The mold is made of one or more materials including, but not limited to, stainless steel, nickel alloy etc. In an exemplary embodiment, the mold is made of stainless steel.
[0061] Fig. 3a depicts an axial cross-sectional view of an exemplary mold 350 used to make the stent 100. The mold 350 is a block-shaped apparatus defining a cavity 350a. The shape of the cavity 350a corresponds to the shape of the stent 100 in its radially expanded state. The dimensions of the cavity 350a of the mold 350 correspond to the dimensions of the stent 100 to be made.
[0062] As shown in Fig. 3b, the mold 350 includes two sections, namely, a top section 351 and a bottom section 353. The top section 351 and the bottom sections 353 are substantially umbrella shaped sections defining respective elongate members 351a, 353a. The elongate members 351a, 353a define a central longitudinal axis of the mold 350. The elongate members 351a, 353a are configured to define the middle portion 113 of the stent 100.
[0063] The two elongate members 351a, 353a are removably coupled to each other to enable the braided structure (or the stent 100) to be mounted inside the mold 350 (as shown in Fig. 3c). In the depicted embodiment, as shown in Fig. 3b, the elongate member 353a is provided with a projection 353b having a plurality of threads. Accordingly, the elongate member 351a is provided with a slot (not shown) having a plurality of threads. The plurality of threads of the projections 353b are configured to mate with the plurality of threads of the slot to couple the top section 351 to the bottom section 353, after mounting the braided structure within the cavity 350a and the elongate members 351a, 353a. When required, the top section 351 and the bottom section 353 are decoupled to recover the braided structure/stent 100 from the mold 350.
[0064] At step 309, the stent 100 obtained from step 307 is subjected to a secondary shape setting process for a pre-defined temperature and a pre-defined time period. The pre-defined temperature ranges from 450°C to 500 °C. The pre-defined time period ranges from 3 minutes to 5 minutes. In an exemplary embodiment, the stent 100 was subjected to a temperature of 480 °C for 4 minutes. The secondary shape setting process helps to set the shape/structure of the stent 100, in its radially expanded state.
[0065] At step 311, the stent 100 is treated with one or more chemicals. The one or more chemicals include, but are not limited to, a solution of at least one of nitric acid, sulfuric acid, hydrofluoric acid, acetic acid, etc. In an exemplary embodiment, the stent 100 is treated with 50% nitric acid (v/v). The treatment of the stent 100 with chemicals helps to remove any oxide layer from the outer surface of the stent 100.
[0066] For chemically treating the stent 100, a surface passivation solution is prepared. The surface passivation solution includes 40% (v/v) to 60% (v/v) of at least one of nitric acid, sulfuric acid, hydrofluoric acid, acetic acid, etc. In an exemplary embodiment, the surface passivation solution includes 50% (v/v) nitric acid. The stent 100 is put into the surface passivation solution, and the surface passivation solution is stirred at a pre-defined speed, at a pre-defined temperature for a pre-defined time. The pre-defined speed ranges from 700 rpm to 900 rpm. The pre-defined temperature ranges from 44 °C to 48 °C. The pre-defied time period ranges from 30 minutes to 40 minutes. In an exemplary embodiment, the stent 100 is completely immersed in the surface passivation solution, and the surface passivation solution is stirred using a magnetic stirrer at 800 rpm, 46 °C for 35 minutes. The stent 100 is recovered from the surface passivation solution and immersed into a 10% (w/v) sodium bicarbonate solution for 1 minute. The stent 100 is then immersed in hot water maintained at 60 °C to 80 °C and sonicated for 15 minutes to 20 minutes. As described above, the stent 100 is treated with the surface passivation solution, sodium bicarbonate solution and then in hot water for 6-7 times to completely remove any oxide layer present on the outer surface of the stent 100.
[0067] At step 313, the loose ends of the monofilaments of the stent 100 obtained from step 311 are welded together to obtain the stent 100. Other functionally equivalent means of coupling the loose ends of the monofilaments together are within the scope of the teachings of the present disclosure. In an exemplary embodiment, the loose ends of the nitinol wires of the stent 100 towards the proximal end 100a are welded using a laser welding machine.
[0068] The stent 100 obtained from step 313 is optionally sterilized with, for example, ethylene oxide (EtO) gas, or gamma radiation, prior to its deployment.
[0069] Fig. 4 depicts a lateral cross-sectional view of an exemplary delivery system 400 of the present disclosure. Figs. 4a and 4b depict an enlarged view of a portion of the delivery system 400 as depicted in Fig. 4. Fig. 4b1 depicts an exploded top view of a portion of the delivery system 400 as depicted in Fig. 4. The delivery system 400 includes a plurality of components including, but not limited to, a handle 410 (also depicted in Fig. 4c), an outer sheath 430, a pusher 450 (also depicted in Fig. 4d), a needle 470 (also depicted in Fig. 4e), one or more pulleys 490, etc. The delivery system 400 extends between a proximal end 400a and a distal end 400b. The proximal end 400a and the distal end 400b are used as a reference to describe the respective ends of the plurality of components of the delivery system 400. The delivery system 400 allows the stent 100 to be deployed across the trabecular meshwork 10 via a minimally invasive deployment procedure.
[0070] The handle 410 is disposed at the proximal end 400a. The handle 410 may have a pre-defined shape that enables a medical practitioner to hold and manipulate the delivery system 400 ergonomically during the deployment of the stent 100. The handle 410 is made of one or more materials including, but not limited to, acrylonitrile butadiene styrene (ABS), polypropylene (PP), polyethylene, polyether ether ketone (PEEK), etc. In an exemplary embodiment, the handle 410 is made of ABS. The handle 410 has a length ranging from 95 mm to 105 mm. The handle 410 has a maximum width ranging from 18 mm to 22 mm. In an exemplary embodiment, the length and width of the handle 410 is 100 mm and 20 mm, respectively.
[0071] The handle 410 is at least partially hollow with at least one opening 410a. The opening 410a is disposed towards the distal end 400b of the handle 410. The handle 410 is configured to support and hold at least a few of the components from the plurality of components of the delivery system 400.
[0072] The handle 410 includes a knob 411 at least partially protruding out of a slot 410b of the handle 410. In the depicted embodiment, as shown in Fig. 4c, the slot 410b extends axially along a length of the handle 410. In an exemplary embodiment, the knob 411 is rotatably coupled to the handle 410 by a stud provided on an inner surface of the handle 410. The stud acts as an axis of rotation of the knob 411. In an exemplary embodiment, as shown in Fig. 4b1, the stud includes a male stud ‘ms’ and a female stud ‘fs’ disposed on respective opposite inner surfaces of the handle 410. The knob 411 is rotatably mounted on the male stud ‘ms’. The female stud ‘fs’ is configured to receive a portion of the male stud ‘ms’, thereby preventing the knob 411 to come out of the male stud ‘ms’.
[0073] The knob 411 is configured to rotate relative to the handle 410. The knob 411 is provided with a plurality of gear teeth. Alternatively, as shown in Fig. 4, the knob 411 is provided with a gear pulley 411a having a plurality of first gear teeth 411b. The gear pulley 411a may be disposed concentrically with the knob 411 and coupled thereto with the help of the stud (as shown in Fig. 4b1). In an exemplary embodiment, the knob 411 and the gear pulley 411a are integrally formed as a single unit. The gear pulley 411a is configured to rotate simultaneously with the knob 411. The knob 411 and the gear pulley 411a are circular in shape.
[0074] The knob 411 and the gear pulley 411a is made of one or more materials including, but not limited to acrylonitrile butadiene styrene (ABS), polypropylene (PP), polyethylene, etc. In an exemplary embodiment, the knob 411 and the gear pulley 411a is made of ABS. The knob 411 has a pre-defined diameter ranging from 20 mm to 24 mm. The gear pulley 411a has a pre-defined diameter ranging from 10 mm to 14 mm. In an exemplary embodiment, the diameter of the knob 411 and the gear pulley 411a is 22 mm and 12 mm respectively. Additionally, or optionally, the knob 411 is provided with a plurality of peripheral ridges that enables the medical practitioner to comfortably rotate the knob 411 without slipping. The knob 411 enables the medical practitioner to control the amount/degree of radial expansion of the stent 100 during deployment of the stent 100. In other words, the knob 411 is rotated in a pre-defined direction to gradually radially expand the stent 100 and the knob 411 is rotated in the other direction to gradually radially collapse the stent 100, as required. In an exemplary embodiment, the knob 411 is rotated towards the distal end 400b to radially expand the stent 100 and the knob 411 is rotated towards the proximal end 400a to radially collapse the stent 100. In an alternative embodiment, the knob 411 is rotate towards the proximal end 400a to radially expand the stent 100 and the knob 411 is rotated towards the distal end 400b to radially collapse the stent 100.
[0075] Although the delivery system 400 is described with the example of the knob 411, the delivery system 400 may include other functionally equivalent structures (for example, a lever/slider or the like) instead of the knob 411 and the same are within the scope of the teachings of the present disclosure.
[0076] The outer sheath 430 is disposed towards the distal end 400b of the delivery system 400 and at least partially coupled to the distal end 400b of the handle 410. As shown in Fig. 4, the proximal end 400a of the outer sheath 430 is coupled to the opening 410a of the handle 410. The outer sheath 430 defines a lumen 430a (as shown in Fig. 4a) that is at least partially aligned with the opening 410a of the handle 410. In an exemplary embodiment, the outer sheath 430 is coupled to the opening 410a of the handle 410 with the help of a press-fit coupling. The outer sheath 430 helps to constrain the stent 100 in its radially collapsed state and helps to position the stent 100 at the trabecular meshwork 10 for the stent 100 to be deployed.
[0077] The outer sheath 430 may include one or more layers. In an exemplary embodiment, the outer sheath 430 includes one layer. The outer sheath 430 is made of one or materials including, but not limited to stainless steel, nitinol, cobalt-chromium (CoCr), etc. In an exemplary embodiment, the outer sheath 430 is made of stainless steel. The outer sheath 430 may have a pre-defined lateral cross-sectional shape including, but not limited to, circular, rectangle, elliptical, square, etc. In an exemplary embodiment, the lateral cross-sectional shape of the outer sheath 430 is circular. The outer sheath 430 has a pre-defined length ranging from 45 mm to 55 mm. The outer sheath 430 has a pre-defined diameter ranging from 0.29 mm to 0.31 mm. The diameter of the outer sheath 430 may either be uniform or tapering across the length of the outer sheath 430. In an exemplary embodiment, the diameter of the outer sheath 430 is uniform along its entire length, and the length and diameter of the outer sheath 430 is 50 mm and 0.3 mm respectively.
[0078] The pusher 450 is movably disposed at least partially within the lumen 430a of the outer sheath 430 and at least partially within the handle 410 (across the opening 410a). The pusher 450 defines a lumen 450a. The pusher 450 is made of one or more materials including, but not limited to acrylonitrile butadiene styrene (ABS), polypropylene (PP), polyethylene, polyether ether ketone (PEEK), etc. In an exemplary embodiment, the pusher 450 is made of ABS. The pusher 450 may have a pre-defined lateral cross-sectional shape including, but not limited to, circular, rectangle, elliptical, square etc. In an exemplary embodiment, the lateral cross-sectional shape of the pusher 450 is circular. The pusher 450 has a pre-defined length ranging from 90 mm to 110 mm. The pusher 450 has a pre-defined diameter ranging from 0.16 mm to 0.20 mm. The diameter of the pusher 450 may either be uniform or tapering across the length of the pusher 450. In an exemplary embodiment, the diameter of the pusher 450 is uniform along its entire length, and the length and diameter of the pusher 450 is 100 mm and 0.18 mm respectively.
[0079] The distal end 400b of the pusher 450 is provided with a bumper 451. The bumper 451 is either coupled to or integrally formed with the pusher 450. In an exemplary embodiment, the bumper 451 is integrally formed with the pusher 450. The bumper 451 may optionally be provided with one or more axially extending ridges 451a. The number of axially extending ridges 451a ranges from four to eight. In an exemplary embodiment, the bumper 451 includes six ridges 451a. The ridges 451a has a pre-defined length ranging from 40 microns to 60 microns. The length of each of the ridges 451a may be same or different. In an exemplary embodiment, the length of all the ridges 451a is the same, and is 50 microns. The ridges 451a are configured to abut an inner surface of the stent 100 towards the proximal end 100a, in its radially collapsed state, thereby enabling the pusher 450 to either push or pull the stent 100 relative to the outer sheath 430 without slipping.
[0080] The bumper 451 defines a lumen which is an extension of the lumen 450a of the pusher 450. The bumper 451 is made of one or more material including, but not limited to, acrylonitrile butadiene styrene (ABS), polypropylene (PP), polyethylene, polyether ether ketone (PEEK), etc. In an exemplary embodiment, the bumper 451 is made of ABS. The bumper 451 has a pre-defined length ranging from 0.08 mm to 0.12 mm. The bumper 451 has a pre-defined diameter ranging from 0.18 mm to 0.22 mm. The diameter of the bumper 451 may either be uniform or tapering across the length of the bumper 451. In an exemplary embodiment, the diameter of the bumper 451 is uniform along its entire length, and the length and diameter of the bumper 451 is 0.1 mm and 0.2 mm respectively. The bumper 451 helps to push the stent 100 out of the outer sheath 430 during the deployment of the stent 100. If required, the bumper 451 helps to pull the stent 100 within the outer sheath 430 during deployment of the stent 100, for example, to reposition the stent 100.
[0081] The pusher 450 is operationally coupled to the knob 411. At least a length of an outer surface of the pusher 450, towards the proximal end 400a, is provided with a plurality of second gear teeth 453. The length of the pusher 450 provided with the second gear teeth 453 ranges from 95 mm to 105 mm. In an exemplary embodiment, the length of the pusher 450 provided with the second gear teeth 453 is 100 mm. The plurality of second gear teeth 453 of the pusher 450 at least partially mate with the plurality of first gear teeth 411b of the knob 411 (or the gear pulley 411a). The interaction between the plurality of second gear teeth 453 and the plurality of first gear teeth 411b facilitates a rotational motion of the knob 411 to be translated to a linear motion of the pusher 450. The direction of the linear motion of the pusher 450 corresponds to the direction of the rotational motion of the knob 411. In an exemplary embodiment, rotating the knob 411 towards the distal end 400b pushes the pusher 450 towards the distal end 400b of the delivery system 400 and vice versa. In another exemplary embodiment, rotating the knob 411 towards the proximal end 400a pushes the pusher 450 towards the distal end 400b of the delivery system 400 and vice versa.
[0082] To change the amount of linear motion of the pusher 450 per unit rotation of the knob 411, different dimensions of the first gear teeth 411b, second gear teeth 453 and the diameter of the knob 411/gear pulley 411a may be used. This is analogous to the use of different gear ratios in systems that operate with multiple gears or the like. Accordingly, the gear ratios of the delivery system 400 may be set that allows precise control over the movement of the pusher 450 thereby allowing complete control over the amount/degree of radial expansion of the stent 100 during the deployment procedure. For every unit rotation of the knob 411, the pusher 450 is moved in the range of 0.05 mm to 0.07 mm. In an exemplary embodiment, for every unit rotation of the knob 411, the pusher 450 is moved by 0.06 mm.
[0083] The needle 470 is movably disposed at least partially within the lumen 450a of the pusher 450 and at least partially within the handle 410 (across the opening 410a). The needle 470 is made of one or more materials including, but not limited to stainless steel, nitinol, cobalt-chromium (CoCr), etc. In an exemplary embodiment, the needle 470 is made of stainless steel. The needle 470 may have a pre-defined lateral cross-sectional shape including, but not limited to, circular, rectangle, elliptical, square, etc. In an exemplary embodiment, the lateral cross-sectional shape of the needle 470 is circular. The needle 470 has a pre-defined length ranging from 110 mm to 130 mm. The needle 470 has a pre-defined diameter ranging from 0.70 mm to 0.80 mm. The diameter of the needle 470 may either be uniform or tapering across the length of the needle 470. In an exemplary embodiment, the diameter of the needle 470 is uniform along its entire length, and the length and diameter of the needle 470 is 120mm and 0.75 mm respectively.
[0084] At least a length of the needle 470 protrudes out of the pusher 450 and the outer sheath 430, towards the distal end 400b. At the distal end 400b, the needle 470 has a tabbed portion 471 with a pre-defined axial cross-sectional shape. The pre-defined axial cross-sectional shape of the tabbed portion 471 is at least one of rhombus, pointy, elliptic, parabolic, etc. In an exemplary embodiment, as shown in Fig. 4, the axial cross-sectional shape of the tabbed portion 471 is rhombus. The tabbed portion 471 has a pre-defined length ranging from 0.09 mm to 0.11 mm. The tabbed portion 471 has a maximum width ranging from 0.11 mm to 0.27 mm. In an exemplary embodiment, the length and maximum width of the tabbed portion 471 is 0.9 mm and 0.11 mm respectively. The tabbed portion 471 helps to puncture the tissue (for example, the cornea of the eye) before the stent 100 is deployed.
[0085] The tabbed portion 471 helps to at least partially pull the stent 100, thereby maintaining an expanded portion of the stent 100 between the tabbed portion 471 of the needle 470 and the distal end 400b of the outer sheath 430. In other words, the tabbed portion 471 at least partially abuts the distal end 100b of the stent 100, while the stent 100 is being radially expanded using the delivery system 400. This helps to deploy the stent 100 in a controlled manner without causing inadvertent trauma to the surrounding tissue.
[0086] The needle 470 is operationally coupled to the knob 411. The proximal end 400a of the needle 470 is coupled to the knob 411 via the pulley(s) 490 and at least one cable 491. The cable 491 is coupled to the pulley 490 disposed rotatably within the handle 410. In an exemplary embodiment, the pulley 490 is rotatably coupled to the handle 410 by a stud provided on an inner surface of the handle 410. The stud acts as an axis of rotation of the pulley 490. In an exemplary embodiment, as shown in Fig. 4b1, the stud includes a male stud ‘ms’ and a female stud ‘fs’ disposed on respective opposite inner surfaces of the handle 410. The pulley 490 is rotatably mounted on the male stud ‘ms’. The female stud ‘fs’ is configured to receive a portion of the male stud ‘ms’, thereby preventing the pulley 490 to come out of the male stud ‘ms’. The pulley 490 helps to provide support to the cable 491. In an exemplary embodiment, as shown in Fig. 4, the handle 410 is provided with one pulley 490. The pulley 490 is made of one or more materials including, but not limited to, acrylonitrile butadiene styrene (ABS), polypropylene (PP), polyethylene, polyether ether ketone (PEEK), etc. In an exemplary embodiment, the pulley 490 is made of ABS. The pulley 490 has a pre-defined diameter ranging from 10 mm to 14 mm. In an exemplary embodiment, the diameter of the pulley 490 is 12 mm. The pulley 490 may be provided with a groove, ledge or the like configured to at least partially receive the cable 491.
[0087] The cable 491 is made of one or more materials including, but not limited to, polytetrafluoroethylene (PTFE), polyethylene, etc. In an exemplary embodiment, the cable 491 is made of PTFE. The cable 491 has a lateral cross-sectional shape. In an exemplary embodiment, the lateral cross-sectional shape of the cable 491 is circular. The cable 491 has a pre-defined diameter ranging from 0.18 mm to 0.22 mm. In an exemplary embodiment, the diameter of the cable 491 is 0.2 mm.
[0088] The cable 491 has two ends, namely a first end 491a and a second end 491b. In an exemplary embodiment, the proximal end 400a of the needle 470 is coupled to the first end 491a of the cable 491 via a knot. In an exemplary embodiment, the second end 491b of the cable 491 is coupled to the gear pulley 411a via a knot. At least a length of the cable 491 is configured to be wound around either the gear pulley 411a or the knob 411.
[0089] In an exemplary embodiment, as shown in Fig. 4, the cable 491 extends from the proximal end 400a of the needle 470, to the pulley 490 and is then at least partially wound around the gear pulley 411a. The cable 491 helps to linearly pull the needle 470 within the lumen 450a of the pusher 450 corresponding to the rotational motion of the knob 411. In other words, as the knob 411 is rotated in a pre-defined direction to push the pusher 450 towards the distal end 400b, the needle 470 is simultaneously pulled within the lumen 450a of the pusher 450 towards the proximal end 400a. The relative motion of the needle 470 and the pusher 450 helps to maintain an expanded portion of the stent 100 between the tabbed portion 471 of the needle 470 and the distal end 400b of the outer sheath 430, while the stent 100 is being radially expanded using the delivery system 400. This helps to deploy the stent 100 in a controlled manner without causing inadvertent trauma to the surrounding tissue.
[0090] Fig. 5 depicts an exemplary method 500 to deploy the stent 100 using the delivery system 400 of the present disclosure. The method 500 commences at step 501 by assembling the stent 100 and the delivery system 400, i.e., loading the stent 100 within the delivery system 400.
[0091] In an exemplary embodiment, a portion of the stent 100 towards the proximal end 100a, is manually crimped by winding a thread or the like to at least partially reduce the diameter of stent 100 at the said portion. Thereafter, the proximal end 100a of the stent 100 is manually mounted on the bumper 451 of the pusher 450 of the delivery system 400. Once the portion of the stent 100 is secured between the bumper 451 of the pusher 450 and the outer sheath 430, the thread is recovered from the stent 100. Then the knob 411 is rotated in a pre-defined direction to pull the pusher 450 within the outer sheath 430 (towards the proximal end 400a) and pull the stent 100 along with it. The stent 100 gradually decreases in diameter as it enters the lumen 430a of the outer sheath 430. Once the entire length of the stent 100 is disposed between the outer sheath 430 and the needle 470, the stent 100 is said to be in the radially crimper state.
[0092] The stent 100, in its radially crimped state, is mounted over the needle 470 of the delivery system 400. The distal end 100b of the stent 100 at least partially abuts the tabbed portion 471 of the needle 470 towards the distal end 400b. And, the proximal end 100a of the stent 100 is mounted on the bumper 451 of the pusher 450. The ridges 451a of the bumper 451 abuts a portion of an inner surface of the stent 100 to help push/pull the stent 100 relative to the outer sheath 430. The entire length of the stent 100 is constrained within the lumen 430a of the outer sheath 430.
[0093] Alternatively, the stent 100 may be pre-loaded within the delivery system 400 and made available to the medical practitioner as an assembly as shown in Fig. 5a. The ophthalmic stent 100 is configured to be mounted in the radially collapsed state on the needle 470 between the tabbed portion 471 and on the bumper 451 of the delivery system 400.
[0094] As shown in Fig. 5a, in the radially compressed state of the stent 100, the stent 100 has an elongated cylindrical-shaped structure. The length of the stent 100, in the radially compressed state ranges from 0.6 mm to 0.8 mm. The diameter of the stent 100, in the radially compressed state ranges from 0.23 mm to 0.25 mm. In an exemplary embodiment, in the radially compressed state of the stent 100, the length and diameter of the stent 100 is 0.7 mm and 0.24 mm respectively.
[0095] At step 503, the tabbed portion 471 of the needle 470 is used by the medical practitioner to create a puncture through one or more tissues (for example, the cornea of the eye, and the trabecular meshwork 10) to advance at least a portion of the delivery system 400. In an exemplary embodiment, at least a portion of the outer sheath 430 towards the distal end 400b is advanced within the eye to position the tabbed portion 471 of the needle 470 across the trabecular meshwork 10.
[0096] At step 505, after the medical practitioner is satisfied with the position of the distal end 400b of the delivery system 400, the knob 411 is at least partially rotated in the pre-defied direction to at least partially expand the stent 100. In an exemplary embodiment, the peripheral portion 111 of the stent 100 disposed adjacent the tabbed portion 471, is expanded at least partially within the Schlemm’s canal 13 across the trabecular meshwork 10.
[0097] In an exemplary embodiment, the peripheral portion 111 of the stent 100 is at least partially expanded by rotating the knob 411 and simultaneously pushing the pusher 450 towards the distal end 400b and pulling the needle 470 towards the proximal end 400a. Pushing the pusher 450 at least partially reveals the stent 100 by pushing the stent 100 from within the lumen 430a of the outer sheath 430. Gradually revealing the stent 100 from within the outer sheath 430 gradually removes the constraint on the stent 100 provided by the outer sheath 430, causing the stent 100 to at least partially self-expand from the radially compressed state (as shown in Fig. 5a) to a partially expanded state (as shown in Fig. 5b). The needle 470 is pulled within the lumen 450a of the pusher 450 such that the tabbed portion 471 of the needle 470 continues to abut the distal end 100b of the stent 100 while it is being revealed from within the lumen 430a of the outer sheath 430 and radially expanded. The relative motion of the needle 470 and the pusher 450 help to maintain an expanded portion of the stent 100 between the tabbed portion 471 of the needle 470 and the distal end 400b of the outer sheath 430, while the stent 100 is being radially expanded using the delivery system 400. This helps to deploy the stent 100 in a controlled manner without causing inadvertent trauma to the surrounding tissue.
[0098] After step 505, Fig. 5c depicts the complete radial expansion of one of the peripheral portions 111 of the stent 100 that is disposed adjacent to the tabbed portion 471 of the needle 470.
[0099] At step 507, the pusher 450 and the needle 470 is relatively moved as described above to reveal and deploy the at least a portion of the middle portion 113 of the stent 100 across the trabecular meshwork 10. In an exemplary embodiment, the central segment 113c of the middle portion 113 is revealed from within the lumen 430a of the outer sheath 430 and deployed across the trabecular meshwork 10. The middle portion 113 radially expands as it is revealed from within the lumen 430a of the outer sheath 430.
[00100] At step 509, the pusher 450 and the needle 470 are relatively moved as described above to reveal and expand the peripheral portion 111 of the stent 100 disposed towards the bumper 451 of the pusher 450. In an exemplary embodiment, the peripheral portion 111 of the stent 100 is radially expanded within the anterior chamber 11 of the eye, thereby firmly capturing the trabecular meshwork 10 between the two peripheral portions 111 of the stent 100 (as shown in Fig. 1). The disposition of the trabecular meshwork 10 between the peripheral portions 111 of the stent 100 prevent risk of loosening/dislodgement and migration of the stent 100.
[00101] After step 509, Fig. 5d depicts the complete radial expansion of the stent 100 from its radially collapsed state to its radially expanded state.
[00102] At step 511, the delivery system 400 is withdrawn from within the eye leaving the stent 100 deployed across the trabecular meshwork 10. The diameter of the middle portion 113 of the stent 100 is more than the maximum width of the tabbed portion 471 of the needle 470, thereby allowing the needle 470 to be withdrawn across the stent 100.
[00103] The stent 100 creates an artificial pathway for the AH to pass through across the diseased/blocked trabecular meshwork 10 from the anterior chamber 11 to the Schlemm’s canal 13, thereby preventing the IOP to increase uncontrollably.
[00104] The scope of the invention is only limited by the appended patent claims. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the teachings of the present invention is/are used. ,CLAIMS:WE CLAIM
1. An ophthalmic stent (100) having a proximal end (100a) and a distal end (100b), comprising:
a. two peripheral portions (111), one each at the proximal end (100a) and the distal end (100b), each of the two peripheral portions (111) define a ring-shaped body having a central hole (111a), the ring-shaped body includes a pre-defined height ranging from 0.09 mm to 0.11 mm and a plurality of rows of first closed cells (111d) arranged circumferentially; and
b. a middle portion (113) coupled between the holes (111a) of the two peripheral portions (111), the middle portion (113) defines a lumen (113a), at least an end segment (113b) of the middle portion (113) towards the proximal end (100a) and the distal end (100b) is encircled by respective ring-shaped body of respective peripheral portion (111), the middle portion (113) defines a plurality of rows of second closed cells (113d) arranged circumferentially;
wherein, the two peripheral portions (111) and the middle portion (113) are braided with a plurality of monofilaments having shape memory properties.
2. The ophthalmic stent (100) as claimed in claim 1, wherein the plurality of monofilaments is braided at a pre-defined braiding angle ranging from 90° to 160°.
3. The ophthalmic stent (100) as claimed in claim 1, wherein a vertical tapering edge (111b) of the ring-shaped body defines an angle ‘a’ ranging from 90° to 160° with respect to a horizontal axis ‘x’.
4. The ophthalmic stent (100) as claimed in claim 1, wherein the end segment (113b) is tapered having a diameter gradually reducing from the hole (111a) of the peripheral portion (111) to a central segment (113c) of the middle portion (113).
5. The ophthalmic stent (100) as claimed in claim 1, wherein a free-end (111c) of the ring-shaped body defines a plurality of crowns (111c1) ranging from four to eight.
6. The ophthalmic stent (100) as claimed in claim 1, wherein shape of the first closed cells (111d) and the second closed cells (113d) is at least one of diamond, rhombus, square, and triangle.
7. The ophthalmic stent (100) as claimed in claim 1, wherein an area of the first closed cells (111d) increases from the hole (111a) of the peripheral portion (111) to the a free-end (111c) of the peripheral portion (111), the ratio between the area of the first closed cell 111d disposed adjacent the free-end 111c and the first closed cell 111d disposed adjacent the hole 111a ranges from 38:25 to 25:20.
8. The ophthalmic stent (100) as claimed in claim 1, wherein an area of the second closed cells (113d) increases from a central segment (113c) of the middle portion (113) to the end segment (113b) of the middle portion (113), the ratio between the area of the second closed cell 113d disposed adjacent the hole 111a and the second closed cell 113d disposed adjacent the central segment 113c ranges from 30:27 to 26:23.
9. The ophthalmic stent (100) as claimed in claims 8 and 9, wherein a ratio between the area of the second closed cells (113d) disposed adjacent the central segment (113c) and the area of the first closed cell (111d) disposed adjacent the free-end (111c) ranges from 9:6 to 7:4.
10. A delivery system (400) comprising:
a. a proximal end (400a) and a distal end (400b);
b. a handle (410) disposed at the proximal end (400a) and including a knob (411),
c. an outer sheath (430) defining a lumen (430a) and coupled to a distal end (400b) of the handle (410),
d. a pusher (450) defining a lumen (450a) and movably disposed within the lumen (430a) of the outer sheath (430), the pusher (450) being operationally coupled to the knob (411), the pusher (450) including a bumper (451) disposed at its distal end (400b), and
e. a needle (470) including a tabbed portion (471) and movably disposed within the lumen (450a) of the pusher (450), the needle (470) operationally coupled to the knob (411);
wherein, the knob (411), upon rotation in a pre-defined direction, is configured to simultaneously push the pusher (450) towards the distal end (400b) and pull the needle (470) towards the proximal end (400a).
11. The delivery system (400) as claimed in claim 10, wherein the knob (411) is provided with a gear pulley (411a) having a plurality of first gear teeth (411b).
12. The delivery system (400) as claimed in claim 11, wherein the pusher (450) is provided with a plurality of second gear teeth (453) at the proximal end (400a) configured to mate with the plurality of first gear teeth (411b).
13. The delivery system (400) as claimed in claim 10, wherein the proximal end (400a) of the needle (470) is coupled to the knob (411) with the help of at least one cable (491).
14. The delivery system (400) as claimed in claim 13, wherein the cable (491) is coupled to at least one pulley (490) disposed rotatably within the handle (410).
15. The delivery system (400) as claimed in claim 10, wherein the bumper (451) is provided with a plurality of axially extending ridges (451a).
16. An assembly comprising:
a. an ophthalmic stent (100) as claimed in any of the preceding claims 1-10;
b. a delivery system (400) as claimed in any of the preceding claims 11-15;
wherein, the ophthalmic stent (100) is configured to be mounted in a radially collapsed state on a needle (470) between a tabbed portion (471) and on a bumper (451) of the delivery system (400).