Title of Invention: EPISCLERAL IMPLANT FOR FILTERING SURGERY OF GLAUCOMA

Technical Field

[0001 ] The present invention relates to an episcleral implant for the filtering surgery of glaucoma and to the surgical technique for its use during trabeculectomy. The implant can also be used in other filtering surgical techniques with aqueous humor outflow under the conjunctiva.

Background Art

[0002] Glaucoma is an eye disease characterized by an irreversible damage to the optic nerve and it is a leading cause of blindness worldwide. Main risk factor for the optic nerve damage is the increased intraocular pressure, and treatment of glaucoma is currently based on a reduction of the intraocular pressure; treatment is started with topical medical therapy, with several drugs, in monotherapy or in combination; in case of insufficient intraocular pressure control, parasurgical laser treatment and, more effectively, surgery, can be performed. (Jonas JB, Aung T, Bourne RR, Bron AM, Ritch R, Panda-Jonas S. Glaucoma. Lancet. 2017 Nov 11 ;390(10108):2183-2193)

[0003] Trabeculectomy is a surgical technique used for over 50 years for the treatment of glaucoma, and it is the most commonly performed intervention for this disease. In brief, aiming to lower the intraocular pressure, a new permanent drainage outflow channel is created allowing the aqueous humor to exit from the eye; during this surgery, after a conjunctival flap creation, and the dissection of a thin scleral flap, a small block of trabeculum is excised under the scleral flap; the aqueous humor exit from the eye, flows under the scleral flap to the subconjunctival space, where it elevates the conjunctiva creating a small elevated bleb (filtering conjunctival bleb); then it diffuses in the different directions and it is reabsorbed by the surrounding tissues. (Khaw PT, Chiang M, Shah P, Sii F, Lockwood A, Khalili A. Enhanced Trabeculectomy: The Moorfields Safer Surgery System. Dev Ophthalmol. 2017;59:15-35.)

[0004] Main cause of long-term failure of trabeculectomy is the scarring of the tissues in the region of the filtering bleb, causing a block of aqueous outflow and diffusion. (Lim R. The surgical management of glaucoma: A review. Clin Exp Ophthalmol. 2022 Mar;50(2):213-231 )

[0005] Aiming to reduce the scarring processes, during surgery, anti-fibrotic agents are applied over the sclera and under the conjunctiva; in post-operative period, several techniques are used for improving aqueous humor outflow and reducing the scarring (removal I laser lysis of scleral flap sutures, bulbar massage, bleb needling, subconjunctival injection of steroids and of anti-fibrotic agents). (Bettin P, Di Matteo F. Postoperative Management of Penetrating and Nonpenetrating External Filtering Procedures. Dev Ophthalmol. 2017;59:53-66)

[0006] In spite of these interventions, many patients (until 30% at three years after the surgery) may undergo a failure of the surgery with increase of intraocular pressure and require new treatments. (Gedde SJ, Feuer WJ, Lim KS, Barton K, Goyal S, Ahmed UK, Brandt JD; Primary Tube Versus Trabeculectomy Study Group. Treatment Outcomes in the Primary Tube Versus Trabeculectomy Study after 3 Years of Follow-up. Ophthalmology. 2020 Mar;127(3):333-345).

[0007] In particular, in some cases, the scarring process occurs in the area above the scleral flap, with adhesion of the conjunctiva to the sclera, fibrosis of the filtering bleb, and disruption of the aqueous humor outflow from the eye. In other cases, scarring process occurs around the bleb, reducing the diffusion of the aqueous humor under the conjunctiva, and leading to an encapsulated bleb. (Bettin P, Di Matteo F. Postoperative Management of Penetrating and Nonpenetrating External Filtering Procedures. Dev Ophthalmol. 2017;59:53-66)

Summary of Invention

[0008] This invention is an episcleral device, with a largely fenestrated base, and a convex superficial structure, made of arcuate thick bands; it is to be implanted during trabeculectomy at the superior margin of the scleral flap, with the base in contact with the sclera, and the superior surface to be covered with the conjunctiva.

[0009] The episcleral implant is to be fixed to the sclera by non-absorbable sutures; the superior conjunctiva is to be sutured in an area not above the implant. [0010] The implant aims to avoid the adhesion of the conjunctiva to the sclera in the area of the scleral flap, and to maintain the diffusion of aqueous humor under the conjunctiva in a large surrounding area.

Technical Problem

[0011] Main cause of long-term failure of trabeculectomy is the scarring of the tissues in the region above the scleral flap, (bleb flat) or around the filtering bleb (encapsulated bleb); this leads to a reduction of the outflow the aqueous humor from the eye, and of its diffusion in the subconjunctival space; both factors cause a failure of the intervention with increased intraocular pressure

Solution to Problem

[0012] In this context, the technical purpose of the present invention is to give an implant that avoids the adhesion of the conjunctiva to the sclera (which result in a fibrosis of the bleb), allows the outflow of the aqueous humor from the eye and its diffusion in a large area in the subconjunctival space, and counteracts the scarring processes of the ocular tissues

[0013] the implant is to be used in the most frequent surgery of the glaucoma (trabeculectomy), but also in other antiglaucomatous interventions with aqueous humor outflow from the eye.

[0014] Further aim of this invention is to propose a surgical technique for the application of the implant during trabeculectomy.

Advantageous Effects of Invention

[0015] The episcleral implant, avoiding the adhesion of the conjunctiva to the sclera in the region of the filtering bleb and allowing the outflow of the aqueous humor from the eye and its diffusion in a large area of the subconjunctival space, aim to obtain a long-term success of the filtering surgery.

[0016] The implant can be used in the most frequent glaucoma surgery, and requires only some additional surgical maneuvers, with a large applicability

[0017] Antifibrotic agents can be used during surgery.

[0018] The soft consistency of the implant is intended to not damage the conjunctiva and the superficial structures of the eye. [0019] The position of the implant adjacent to the scleral flap is intended to allow the common post-operative intervention (removal I laser lysis of scleral flap sutures, bulbar massage, bleb needling, subconjunctival injection of steroids and of anti- fibrotic agents).

[0020] This implant can also be used in other filtering surgical techniques for glaucoma with outflow of aqueous humor under the conjunctiva.

Brief Description of Drawings

[0021] The accompanying figures are relative to exemplary embodiments of the present invention, by way of illustration, and without limitations:

[0022] Fig 1 shows a view of the implant according to the present invention

[0023] Fig 2 shows a variant embodiment of the implant with an outflow tube

[0024] Fig 3 shows the sectional view of valve device of the tube of Fig 2

[0025] Fig 4 shows the position of the implant of Fig 1 in relation to scleral flap of the trabeculectomy

[0026] Fig 5 shows the position of the implant of Fig 2 in relation to scleral flap of the trabeculectomy

Description of Embodiments

[0027] As used herein and in the annexed claims the terms of sclera, conjunctiva, trabecular meshwork, aqueous humor, are intended in their usual anatomical meaning: the sclera is the outer fibrotic layer of the eyeball; the conjunctiva is a transparent mucous membrane that lines the inner surface of the eyelids and the anterior surface of the sclera; the trabecular meshwork is the tissue located in the anterior chamber angle of the eye, and creating the resistance to the evacuation of aqueous humor from the eye; the aqueous humor is a transparent fluid produced into the anterior segment of the eye, which has several key functions, and whose reduction of outflow from eye through the trabecular meshwork causes an increase of the intraocular pressure.

[0028] Trabeculectomy is a filtering surgery of the glaucoma, where a small block of trabecular meshwork is removed, creating a pathway for the aqueous humor outflow from the anterior chamber of the eye. The aqueous flows into the subconjunctival space, usually leading to an elevation of the conjunctiva, referred to as a filtering bleb

[0029] The scleral flap is a thin scleral layer, which is created during trabeculectomy, under which is removed a small block of trabecular meshwork

[0030] Filtering bleb is a small elevation of the conjunctiva, created by the aqueous humor which exit from the eye under the conjunctiva after the filtering surgical techniques for glaucoma.

[0031] The implant in the accompanying figures is represented schematically and not necessarily respecting factors of scale and I or proportion between the parts that compose it.

[0032] The implant has an elongated shape; it is hollow, with a base to be positioned on the sclera, and a surface to be covered with the conjunctiva (Fig 1 ).

[0033] In its preferred embodiment, the base of the implant is made of a layer of soft material with thickness ranging between 0.2 and 0.6 mm, with large holes, surrounded by the linear structures (Figure 1 , a) of the base which have a radial disposition along the short section of the implant

[0034] In alternative embodiments of the invention, the base of the implant is made of a layer of soft material with thickness ranging between 0.2 and 0.6 mm, without holes, or with round, oval or rectangular holes.

[0035] Overall, the base has a slightly concave profile, in order to fit, by its shape, and the soft consistency of the material, to the curvature of the scleral surface of the region.

[0036] In its preferred embodiment, the superficial part of the implant is made of the linear structures (Figure 1 , b), made by the same soft material of the base, with a thickness ranging between 0,2 and 0,6 mm;

[0037] The linear structures have an arcuate shape, with the concavity facing the base, to which are joined at its edge, and give to the implant an external convex shape; the linear structures delimit large holes on the surface of the implant; the linear structures can be parallel to the linear structures of the base. [0038] In an alternative embodiment, superficial structure can be a widely fenestrated screen of the same soft material, with a thickness ranging between 0,2 and 0,6 mm, with holes of various shape, disposed in row

[0039] Overall, the superficial structure has a convex profile in longitudinal and transversal section, in order to fit to the eye shape and to not damage the conjunctiva by which it will be covered.

[0040] The implant has, at its lateral ends, supporting elements for fixation to the sclera by means of sutures (Figure 1 , c); alternatively, small plaques with eyelets can be present at lateral ends for fixation to the sclera by means of sutures.

[0041] The implant is made of soft biologically compatible material.

[0042] In an alternative embodiment, the biologically compatible is a polymeric thermal or mechanical shape-memory material with heparin coated surface

[0043] In an alternative embodiment, the implant have a thin tube (Figure 2), fixed at the implant by a small ring, located at the center of the inferior edge of the implant; the tube has a diameter ranging between 100 and 400 micron, is made of the same material o and other biologically compatible material, and it has one or both extremities with many lateral holes; one end of the tube is to be placed under the scleral flap (Figure 2, d), and the other is located into the inner space of the implant (Figure 2, e); the tube improves the flow of aqueous humor from the trabeculectomy to the implant. The tube can have in the inner lumen (Figure 3) a valve made of two flaps (Figure 3, g), allowing only a unidirectional flow of the aqueous humor from the end of the tube placed under the scleral flap to the end located into the implant.

[0044] For surgical technique of implantation, the implant (Figure 4) is to be positioned on the sclera at the superior border of the scleral flap (Figure 4, h), avoiding to cover the flap in any point, and fixed to the sclera by sutures.

[0045] The application of the implant is to be done after the sculpture of the scleral flap, and the application of anti-fibrotic agents; after suturing the implant by nonabsorbable sutures, the surgeon performs the excision of trabecular block and iridectomy; during the suture of the scleral flap, the eventual tube described in figure 3 is placed under the flap (Figure. 5, i); then the implant is covered with conjunctiva; this conjunctiva is sutured in an area not overlying the implant. [0046] In order to avoid early post-operative hypotony, the tube can be temporarily closed by a legature made with an absorbable suture

[0047] The above disclosure shows that the implant and the methods for surgical application allow to avoid that the scarring process impair the function of the filtering bleb

[0048] Those skilled in the art, aiming to meet specific and incidental needs will appreciate some changes and variants to the above described configurations. All these variants and changes shall be contemplated in the scope of the invention, as defined in the claims.

Examples

[0049] An example of the installation of the implant of figure 1 during trabeculectomy. The implant is placed at the superior margin of the scleral flap, (figure 4).

[0050] An example of the installation of the implant with the tube (figure 2) during trabeculectomy. The implant is placed at the superior margin of the scleral flap; one end of the tube is placed under the scleral flap, (figure 5).

Industrial Applicability

[0051 ] The invention can be used in medicine in trabeculectomy and other filtering glaucoma operations in the surgical treatment of various types of glaucoma (primary, refractory, with repeated surgical interventions, in complex cases with secondary glaucoma).

[0052] The implant produced, inspected, packed and sterilized, can be stored in sterile package in operating rooms and used at time of surgery.

Citation List

Jonas JB, Aung T, Bourne RR, Bron AM, Ritch R, Panda-Jonas S. Glaucoma. Lancet. 2017 Nov 1 1 ;390( 10108):2183-2193.

Khaw PT, Chiang M, Shah P, Sii F, Lockwood A, Khalili A. Enhanced Trabeculectomy: The Moorfields Safer Surgery System. Dev Ophthalmol. 2017;59:15-35.

Kirwan JF, Lockwood AJ, Shah P, Macleod A, Broadway DC, King AJ, McNaught Al, Agrawal P; Trabeculectomy Outcomes Group Audit Study Group. Trabeculectomy in the 21 st century: a multicenter analysis. Ophthalmology. 2013 Dec;120(12):2532- 2539.

Lim R. The surgical management of glaucoma: A review. Clin Exp Ophthalmol. 2022 Mar;50(2):213-231.

Bettin P, Di Matteo F. Postoperative Management of Penetrating and Nonpenetrating External Filtering Procedures. Dev Ophthalmol. 2017;59:53-66.

Gedde SJ, Feuer WJ, Lim KS, Barton K, Goyal S, Ahmed I IK, Brandt JD; Primary Tube Versus Trabeculectomy Study Group. Treatment Outcomes in the Primary Tube Versus Trabeculectomy Study after 3 Years of Follow-up. Ophthalmology. 2020 Mar;127(3):333-345.