RU2458663C1 - Transplant for scleroplasty - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medicine, namely to ophthalmology, and is intended for surgical treatment of progressing myopia aimed at prevention of its further progress, as well as for scleroplastic operations in case of other pathologic states of eye. Transplant for scleroplasty with mesh structure is made from biocompatible, biostable material, is spatially cross-linked polymer by photopolymerisation of oligomers of methacryl series in form of 0.2 mm thick film in form of oval, from 15 to 20 mm long, from 7 to 9 mm wide and without sector with arc from 10 to 20 degrees, whose rays converge inside hole with diameter from 1.5 to 3 mm made in transplant. Transplant for scleroplasty is charactrerised by cells of mesh structure with diameter 0.3 mm, which are located in chessboard order with 0.5 mm distance between centres of adjacent cells. Transplant has symmetry axis, which is bisector of sector which is missing in transplant.

EFFECT: transplant for scleroplasty ensures strong connection of synthetic transplant with patient's sclera with absence of negative effects, associated with impairment of feeding of sclera sections under transplant, toxic response.

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Description

The invention relates to medicine, namely to ophthalmology, and is intended for the surgical treatment of progressive myopia in order to prevent its further progression, as well as for scleroplastic operations in other pathological conditions of the eye.

With progressive myopia, the eye increases along the anteroposterior axis, the membranes of the eyeball stretch, which leads to thinning and dystrophic changes in the membranes of the eye (sclera, choroid, retina). As a result of these changes, serious complications can occur (scleral staphyloma, chorioretinal, vitreoretinal dystrophy, retinal detachment, etc.).

Currently, scleroplastic surgery is considered the most effective treatment for progressive myopia.

Scleroplastic surgery consists in the fact that after opening the conjunctiva, various transplantation materials (biological, combined or synthetic) are placed on the sclera surface (under the tenon shell), which are gradually replaced or germinated by the newly formed connective tissue. In this case, the resulting connective tissue (scar) mechanically strengthens the sclera, preventing further growth of the eye and stretching of the membranes, and also improves nutrition of the posterior pole of the eye due to the ingrowth of newly formed vessels.

According to various authors, the effectiveness of sclerotherapy operations depends on the nature of the surgical intervention, the characteristics of the myopic process, the initial condition of the patient's sclera, as well as on the properties and type of implanted material.

Most often, biological material is used for scleroplasty (RU 99102289, RU 93006067, RU 2161021, RU 2089200): (sclera, dura, pericardium of a bovine, collagen sponge, etc.) [1, 2]. However, the use of biological materials poses a number of problems.

1. Allergic and immunological reactions of the patient to biological material.

2. The difficulties of implantation associated with the consistency of biological material that does not have elastic properties.

3. The lack of persistent effect due to resorption of the material used.

4. The complexity of the collection of material, its conservation and storage.

5. The need to study for infections that can be transmitted through transplant material, which not only increases the cost of the material and increases the manufacturing time of the transplant, but also makes it difficult to use in emergency situations.

6. The moral and ethical aspect of the use of biological transplantation material and the imperfection of legal norms.

To eliminate one of the main disadvantages of biological grafts - the lack of a lasting effect after surgery due to resorption of biological tissue (Clause 3), combined and reinforced grafts were proposed (RU 2157159, RU 21402421). However, the remaining disadvantages inherent in biological transplants have not been eliminated.

Therefore, synthetic grafts are currently the most promising for scleroplastic operations [3].

A widespread material for the manufacture of artificial transplants in medicine is silicone rubber. However, silicone is characterized by an increased exit of oligomers and other toxic compounds from the volume of the graft to the outside, in addition, the silicone graft does not merge with the sclera. Therefore, when using silicone grafts at various times after surgery, complications are encountered, such as graft rejection, the formation of pressure sores with sclera perforation, the presence of pain, anterior segment ischemia syndrome, compression syndrome, and graft infection [4, 5].

Other synthetic analogs are also known (RU 96121727, RU 2160123, RU 2297811, etc.) intended for surgical strengthening of the sclera with progressive myopia and made of various synthetic materials having a porous structure. Porous synthetic grafts have advantages in that connective tissue can grow into the porous surface of the graft and tightly fix it, eliminating graft rejection. However, these grafts isolate the areas of the sclera beneath them from the surrounding tissues, prevent the growth of vessels in the sclera and thus can impair the nutrition of the eye tissue, causing ischemia and contributing to the progression of dystrophic processes in the tissues of the myopic eye.

The closest in technical essence is the design described in patent RU 2157159, COMBINED TRANSPLANT FOR SCLEROPLASTY, taken as a prototype. The prototype is a mesh structure with 1x1 mm cells formed by biodegradable collagen-based filaments and synthetic non-biodegradable filaments. Eliminating one of the main disadvantages of biological grafts - the lack of a lasting effect after surgery due to resorption of biological tissue, the prototype does not eliminate the remaining disadvantages inherent in biological and synthetic grafts.

An object of the invention is the elimination of all these disadvantages and the creation of a graft for scleroplasty (scleroplant) that meets modern requirements, which allows to ensure a strong connection of the synthetic graft with the patient’s sclera in the absence of negative effects associated with malnutrition of the sclera under the graft made of biocompatible and biostable material which should not cause any toxic reactions. The developed transplant should be connected to the sclera solely due to the connective tissue germinating into the transplant without a pronounced inflammatory reaction and without disturbing the nutrition of the eye tissues, and should also not impede the growth of blood vessels from the own tissues surrounding the eyes.

The problem is solved in that the developed graft for scleroplasty (scleroplant) is a biocompatible biostable film with a mesh structure made of a spatially cross-linked polymer by photopolymerization of methacrylic series oligomers in the form of an oval 0.2 mm thick, 15 to 20 mm long and wide from 7 to 9 mm without a sector with an arc of 10 to 20 degrees, the rays of which converge inside the holes made in the graft with a diameter of 1.5 to 3 mm, and mesh cells with a diameter of 0.3 mm are located in staggered with a distance between the centers of neighboring cells of 0.5 mm, while the graft has an axis of symmetry, which is the bisector of the sector missing in the graft.

The technical result is achieved by the fact that the graft for scleroplasty (scleroplant) is made of a spatially cross-linked polymer obtained by photopolymerization of methacrylic oligomers. A distinctive feature of this method of production is that the process of product formation eliminates any mechanical effect on the graft. Any mechanical effect on the polymer is known to provoke the formation of free radicals, which subsequently lead to polymer degradation and undesirable toxic reactions.

During the operation, the scleroplant or scleroplant (depending on the method of operation) are installed under the conjunctiva between the sclera and the tenon capsule in the intermuscular sectors. Then the edges of the absent sector are connected, thereby the graft takes a dome-shaped shape (the shape of an eyeball) without the formation of any folds and, if necessary, is fixed to the sclera with suture material. In the future, through the cells of the graft, the connective tissue and blood vessels germinate and “biological fixation” of the graft is achieved. For the manufacture of the graft, a polymer material was synthesized, obtained by photopolymerization of methacrylic oligomers according to RF patent No. 2234417, used in the manufacture of an elastic artificial lens. The specified polymer material is biocompatible, biostable, hydrophobic, does not cause inflammatory reactions or rejection reactions.

The claimed technical result can be obtained only by using the totality of the features of our proposed scleroplant.

Experimental and clinical studies of the developed scleroplant for scleroplastic operations used in the treatment of progressive myopia showed that using all the distinguishing features of the proposed technical solution, the following positive effects were achieved:

- during the operation, the scleroplant is easily implanted, without curling up and wrinkling due to its elastic properties, tightly fits the eyeball without folds due to its configuration;

- in the postoperative period, it adapts well and grows together with the sclera of the patient with the connective tissue and nourishing vessels growing through it;

- in the long-term postoperative period provides a stable effect of myopia stabilization in the absence of allergic, immunological, toxic and other negative reactions from the patient’s body.

The essence of the claimed invention is illustrated by graphic material. Figure 1: view of the transplant for scleroplasty.

A - graft length for scleroplasty from 15 to 20 mm;

In - the width of the graft for scleroplasty from 7 to 9 mm;

C - missing sector with an arc of 10 to 20 degrees;

D is the diameter of the hole made in the center of the graft from 1.5 to 3 mm;

The graft for scleroplasty has a mesh structure with cells (E) with a diameter of 0.3 mm and a distance between the centers of neighboring cells of 0.5 mm.

The claimed graft has been successfully put into practice, which is confirmed by the following clinical examples demonstrating the results of surgical scleroplastic treatment using the claimed graft.

Example 1. Patient M., 10 years old. Diagnosis: mildly acquired progressive myopia of an average degree of both eyes. Visual acuity: right eye - sph -4,0D = 0.9; left eye - sph -4.5D = 0.8. PZO of the right eye = 24.98 mm; PZO of the left eye = 25.08 mm. The fundus is the initial myopic cone.

Scleroplasty was performed using 4 declared transplants 15 mm long and 7 mm wide according to the method of N.N. Pivovarova. The operation and the postoperative period were uneventful. In the postoperative period, dynamic monitoring of visual acuity and PZO of the patient was performed, as well as ultrasound scanning.

A stabilization of the process was achieved, visual acuity increased to 1.0 in both eyes. The fundus without negative dynamics. According to the ultrasound scan, scleroplants are tightly fixed to the sclera. The observation period is 1 year.

Example 2. Patient T., 11 years old. Diagnosis: high-grade, early acquired progressive myopia in both eyes. Visual acuity: right eye - sph -7,0D = 0.7; left eye - sph -6.5D = 0.8. PZO of the right eye = 25.84 mm; PZO of the left eye = 25.52 mm. The fundus is the initial myopic cone, on the extreme periphery of the right eye of the retinoschisis.

Scleroplasty was performed using 4 declared transplants with a length of 20 mm and a width of 9 mm according to the method of N.N. Pivovarova. The operation and the postoperative period were uneventful. In the postoperative period, dynamic monitoring of visual acuity and PZO of the patient was performed, as well as ultrasound scanning.

A stabilization of the process was achieved, visual acuity increased to 0.9 in both eyes. The fundus without negative dynamics. According to the ultrasound scan, scleroplants are tightly fixed to the sclera. The observation period is 1.5 years.

Literature:

1. Zhukova O. V., Smirnitskaya E.Yu., Akimova T.F. The effectiveness of sclerotherapy operations depending on the method of operation and the type of biomaterial. - Materials of the VIII Congress of Ophthalmologists of Russia. Abstracts of reports. - Moscow: 2005 .-- p. 719.

2. Khaustova I.A., Kuznetsova N.P. Xenografts for sclera-strengthening operations. - Materials of the VIII Congress of Ophthalmologists of Russia. - Abstracts. - Moscow: 2005 .-- p. 735.

3. Markosyan G.A., Ivashchenko Zh.N. Results of sclera reinforcement with synthetic grafts with long follow-up. - Materials of the VIII Congress of Ophthalmologists of Russia. Abstracts of reports. - Moscow: 2005 .-- p. 725.

4. Utkin V.F. Strengthening sclera with silicone rubber with progressive myopia. - In the book: The Fifth All-Union Day of Ophthalmologists. - M .: 1979, t.1, - S.157-158.

5. Ilnitsky VV Temporary and permanent episcleral filling in surgery for retinal detachment, its prevention. - Dis. Dr. med. sciences. - M .: 1995.

Claims (2)

1. The graft for scleroplasty with a mesh structure made of a biocompatible, biostable material, characterized in that the graft is made of a spatially cross-linked polymer by photopolymerization of methacrylic oligomers in the form of a 0.2 mm thick film in the form of an oval from 15 to 20 mm long, width from 7 to 9 mm and without a sector with an arc from 10 to 20 °, the rays of which converge inside the hole made in the graft with a diameter of 1.5 to 3 mm, and the graft has an axis of symmetry, which is the bisector of the missing in the implant sector. 2. The graft for scleroplasty according to claim 1, wherein the mesh cells with a diameter of 0.3 mm are staggered with a distance between the centers of adjacent cells of 0.5 mm.

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