RU2336061C1 - Method of cytostatic therapy for prevention of excess scarring resulted from penetrating antiglaucomatous surgery - Google Patents

Abstract

FIELD: medicine; ophthalmology.

SUBSTANCE: cytostatic agent is subconjuctive introduced. Agent introduced is added with 0.08% trypan blue solution in amount 0.05 ml. Introduced agent localisation is visualised. In case agent becomes localized in anterior chamber or escapes through conjunctive suture introduction is stopped. In case agent spreads under conjunctiva dose in required amount is introduced.

EFFECT: lower rate of complications caused by cytostatics introduction.

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Description

The present invention relates to ophthalmology and is intended for the prevention of excessive scarring after penetrating antiglaucomatous surgery.

Currently, glaucoma treatment is carried out by forming an anastomosis between the anterior chamber angle and the intrascleral, suprachoroidal and subconjunctival space.

Given the mixed nature of the obstruction of the outflow of aqueous humor in the corner of the anterior chamber, sinusotrabeculoectomy is the main and most common method for treating glaucoma. This method allows to overcome the trabecular-intrascleral retention of aqueous humor and is used in the treatment of various forms and types of glaucoma.

However, the method is not without drawbacks, the main of which is scarring of the created paths of the outflow of aqueous humor, as a result of which this intervention is characterized by unpredictability of results and poor reliability.

In addition, this method provides for the outflow of aqueous humor mainly into the subconjunctival space, as a result of which it is possible to form cysts of a filtration pad, or external filtration of aqueous humor, or form a giant filtration pad. The presence of such complications leads to the development of a secondary infection, severe hypotension, or to repeated hypertension.

The local use of cytostatic drugs, such as 5-fluorouracil (5-FU), for the prevention of excessive scarring after antiglaucomatous interventions has gradually become the "gold standard" in world practice.

The use of the drug 5-fluorouracil in anti-glaucomatous operations using laser irradiation, iridotomy, sclerostomy in order to reduce intraocular pressure and reduce scarring is known, while fluorouracil is administered subconjunctively at a dosage of 0.2-0.5 ml, once, at the end of the surgery (RU 2091062, 09.27.97).

The use of cytostatics is also known for other types of antiglaucomatous operations (RU 2086218, 08/10/97; RU 2196555, 01/20/2003).

The closest analogue of the proposed method is a method of the same purpose, including the introduction of cytostatic - 5% fluorouracil solution in the form of subconjunctival injections in a single dose of 5 mg. For this, the official solution of fluorouracil was diluted ex tempore 2 times with a sterile isotonic solution and injected under the conjunctiva in an amount of 0.2-0.3 ml. The first injection was made the day before the operation into the superior conjunctival arch, the second and subsequent injections were performed on the 2nd day after the operation and then every other day next to the surgery (3-5 injections in total), as well as into the filter pad (the needle was injected under the conjunctiva 2 mm from the filter pad towards it and passed into the cavity already under the conjunctiva (Shmyreva V.F., Mostovoy E.N. On the use of cytostatic therapy with 5-fluorouracil in glaucoma surgery. // Vestn. Ophthalmology. - 2004. - No. 3. - S.7-10).

However, poor visualization of these drugs creates certain difficulties for their safe and effective use. Cytostatics are toxic to corneal epithelium, vascular endothelium and cause death of limbal stem cells.

In the available literature, we found no mention of effective methods of visualizing solutions of cytostatics for topical application. 5-FU is used as a subconjunctival injection. Fluorouracil is colorless and it is not possible to determine the area of subconjunctival tissues exposed to it. Accurate determination of the area of exposure to the drug is difficult, and is only assumed by the volume of tissues raised by subconjunctival injection. As a result of this, there are no unified recommendations on the maximum allowable impact area. The use of more antimetabolite in an effort to expand the potential exposure zone increases the possibility of unintentional entry into the surrounding eye structures, increasing the risk of complications.

One of the consequences of insufficient visualization of cytostatics in the tissues of the eye is their unrecognizable entry into the tear film. As a result, the incidence of corneal epithelial disease increases. It should also be noted that when using low dilutions of antimetabolites, their seepage into the anterior chamber can lead to the development of serious complications.

The basis of the invention is the idea of visual control over the introduction of these toxic drugs, which can provide a significant reduction in their unintentional effects on eye tissue.

The objective of the invention is to develop an improved method for cytostatic therapy for the prevention of excessive scarring after penetrating antiglaucomatous surgery.

The technical result of the invention is to reduce the incidence of complications with subconjunctival administration of a cytostatic agent associated with its entry into undesirable distribution sites.

The technical result is achieved by controlling the distribution of the drug in the tissues of the eye using its visualization with trypan blue dye.

We conducted studies on the distribution of the cytostatic drug stained with trypan blue with subconjunctival administration in the tissues of the eye and selected the minimum dose of dye necessary for visualization. It turned out that the cytostatic agent can fall during subconjunctival administration, in particular into the anterior chamber of the eye, and leak through the conjunctival suture, which is highly undesirable. This is found when 0.05 ml of a 0.08% trypan blue solution is added to the cytostatic. The nature of the distribution of the colored drug determines the nature of the further administration of the drug. The appearance of a stained cytostatic agent in the anterior chamber or its leakage through the conjunctival suture indicates the need to stop further administration of the drug.

The implementation of the invention

The method is as follows. Penetrating anti-glaucomatous surgery is performed. Cytostatic is administered - 5% solution of 5-fluorouracil (5-FU) in the form of subconjunctival injections in a single dose of 5 mg. For this, the official solution of fluorouracil is diluted ex tempore 2 times with a sterile isotonic solution and injected under the conjunctiva in an amount of 0.2-0.3 ml. 5-FU is maintained in the subconjunctival space adjacent to the area of the filtration pad, or in the subconjunctival and subtenon space of the filtration pad itself, within 1-6 days after surgery. For this, 0.3 ml of a 5% solution of 5-FU is diluted in a syringe (1.0 ml) by adding 0.05 ml of a 0.08% solution of TC (Trypan Blue “Rhex ID”, Appasamy Ocular Devices P. Ltd., India ), achieving uniform light blue staining of the mixture. Other regimes of cytostatic administration are possible, but in each case trypan blue is added to its solution at the indicated dose.

Example:

Example 1. Patient S., 73 years old, was admitted with a diagnosis of open-angle glaucoma III B in the right eye. Visual acuity with correction - 0.4. The intraocular pressure (Po) of the right eye was 30 mm Hg, the coefficient of ease of outflow of intraocular fluid was 0.03.

A penetrating antiglaucomatous operation was performed. On the 3rd day after the operation, a decision was made to conduct cytostatic therapy in the form of a subconjunctival injection of 5-fluorouracil solution. 0.3 ml of a 5% 5-FU solution was mixed in a 1.0 ml syringe, 0.05 ml of a 0.08% trypan solution was added, achieving a uniform light blue color of the drug mixture. Under epibulbar anesthesia, 5-FU was introduced into the subconjunctival and subtenon space of the filter pad. During the introduction, neither blue staining of the anterior chamber moisture, nor external outflow of the solution through the conjunctival suture was noted. The patient was given the entire necessary dose of the drug mixture. Subsequent injections of the cytostatic also carried out visual monitoring of the distribution of the drug in the eye tissues.

Example 2. Patient K., 70 years old, was admitted with a diagnosis of open-angle glaucoma II from the right eye. Visual acuity with correction - 0.7. The intraocular pressure (Po) of the right eye was 31 mm Hg, the coefficient of ease of outflow of intraocular fluid was 0.02.

An antiglaucomatous operation was performed. On the 3rd day after the operation, a decision was made to conduct cytostatic therapy in the form of a subconjunctival injection of 5-fluorouracil solution. 0.3 ml of a 5% 5-FU solution was mixed in a 1.0 ml syringe, 0.05 ml of a 0.08% trypan blue solution was added, achieving a uniform light blue color of the drug mixture. Under epibulbar anesthesia, 5-FU was introduced into the subconjunctival and subtenon space of the filter pad. During the introduction, the appearance of blue staining of the moisture of the anterior chamber was noted, the procedure was immediately stopped.

Thus, the proposed method allows for cytostatic therapy after antiglaucomatous operations with a minimal risk of damage to eye tissue.

Claims (1)

A method of conducting cytostatic therapy for the prevention of excessive scarring after penetrating antiglaucomatous surgery, including subconjunctival administration of 5-fluorouracil, characterized in that the drug is administered with the addition of 0.05 ml of a 0.08% trypan blue solution and visualize its localization during administration, in if the drug enters the anterior chamber or expires through the conjunctival suture, its administration is stopped, and if the drug is distributed under the conjunctiva, the entire necessary dose is administered.