RU2470589C1 - Immersion medium for carrying out volumetric echography of orbit in case of anophthalmia and subatrophy of eye and method of carrying out volumetric echography of orbit in case of anophthalmia and subatrophy of eye - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to ophthalmology and is intended for volumetric echography of orbit in case of anophthalmia or subatrophy of eye. For this purpose claimed is immersion medium which represents cross-linked polymer hydrogel based on modified polyvinyl alcohol of general formula:

where R - H, R₁ - OH, R₂ - unsaturated group, R₃ - O-CO-R₄, R₄ - CH₃ or residue of other acid, from polyvinyl ester of which polyvinyl alcohol was obtained, and m=80-99 mol %, n=0.5-15 mol %, k=0-12 mol %. Said emersion medium is used in echography method in form of 4-6 mm thick disc with size corresponding to opening into orbit. Disc is laid on anterior surface of closed eyelids.

EFFECT: invention ensures optimisation of orbit content image with absence of complications, trauma of eye tissues, as well as reduction of examination time and absence of psychological trauma.

2 cl, 5 ex

Description

The invention relates to ophthalmology and is intended for volumetric echography of the orbit, including anophthalmos, to assess the position and condition of the orbital implant and surrounding tissues, as well as subatrophy of the eyeball.

There are various ways to visualize anatomical features and pathological changes in the orbit. One of the common research methods is ultrasound scanning using two-dimensional ultrasound imaging (for example, RU 2140202, 10.27.99).

When conducting an orbit sonography to obtain a clearer image, an immersion medium is placed between the device’s sensor and the eye.

The use of various immersion media is known in the art. So, for optical studies in order to control the optical parameters of inorganic materials, it is known to use an immersion liquid, which includes zinc iodide, cadmium iodide (RU 2051940, 10.01.96).

It is known to use glycerol or fir oil as an immersion liquid for optical registration of the pattern of skin lines (RU 2314027, 06/20/07).

It is known to use oligel (ophthalmic gel) as an immersion medium for examining the eye using a Goldman lens (RU 2189169, 09/20/2002).

It is known to use vidisic as an immersion medium for conducting confocal corneal microscopy (RU 2407490, 12/27/2010).

However, these immersion media are not used when performing an ultrasound scan of the eye. For this study, a transparent liquid medium, in particular saline or water, is used.

A known method of conducting orbital echography and an immersion medium for conducting it, in which a canister filled with physiological saline is placed between the sensor and the cavity of the orbit on closed eyelids or between the eyelids (RU 2140202, 10.27.99). This results in a planar static image of the spatial structure, a fuzzy image of the tissues.

The closest analogue of the invention is an immersion medium in the form of physiological saline and a method for determining the position and condition of an orbital implant and surrounding tissues during anophthalmus by ultrasonic scanning of an orbit (Shlyakhtov M.I., Zubarev A.B. Method for determining the position and state of an orbital implant and surrounding tissues with anophthalmus by ultrasonic scanning of the orbit. // RU 2248182, 03.20.2005). Before starting ultrasound scanning, a retrobulbar injection of anesthetic in a volume of 3.0 ml is performed. A ring-bath is placed in the conjunctival cavity, which is filled with immersion fluid - physiological saline until the upper part of the test object is completely immersed.

The image on the monitor screen of the ultrasound scan arises due to the fact that different tissues have different reflectivity. The introduction of fluid into the retrobulbar space (posterior pole of the orbit) significantly enhances contrast due to the fact that the fluid does not reflect ultrasound and, being between the musculoskeletal stump (UEC) and adipose tissue, clearly separates one structure from another. Using an anesthetic as a liquid, for example, a 2% lidocaine solution, in a volume of 3.0 ml, the surgeon simultaneously provides the desired contrast of the structures of the posterior pole and anesthetizes the procedure itself (injecting the liquid). The selected volume (3.0 ml) corresponds to the anatomical space of this zone. Measurement of the real size of the OEC becomes possible if a ring-bath is installed in the conjunctival cavity, which is filled with immersion fluid until the upper part of the object under study is completely immersed, thereby eliminating the "dead zone". The disadvantages of the prototype method are the need to perform retrobulbar injection of anesthetic, which can lead to the appearance of retrobulbar hematoma and damage to the optic nerve, as well as the establishment in the conjunctival cavity of the bath ring with saline solution used as an immersion medium, which requires the use of additional anesthesia and may also damage the cornea in the form of edema and erosion, especially with repeated studies.

The objective of the invention is to develop a method of ultrasound of the orbit and immersion medium for its implementation to obtain the most complete echographic picture of the orbit with anophthalmus or subatrophy of the eye.

The technical result of the invention is the possibility of obtaining a volumetric model of the contents of the orbit based on a clear echographic image of the orbit due to optimization of the echographic image in the absence of complications, trauma to the tissues of the eye, as well as reducing the time of investigation and the absence of psychological trauma.

The technical result is achieved by using an immersion medium, which is a polymer hydrogel based on crosslinked polyvinyl alcohol, and placing it on closed eyelids in the form of a disk of a certain thickness and diameter, which ensures the congruence of the ultrasonic sensor with the front surface of the eyelids, with the exception of the presence of a "dead zone" .

As an immersion medium for conducting orbit sonography, a substance is proposed that is a cross-linked polymer hydrogel based on a modified polyvinyl alcohol of the general formula:

where R is H

R ₁ is OH,

R ₂ is an unsaturated group,

R ₃ is O-CO-R ₄ .

R ₄ is CH ₃ or a residue of another acid from which polyvinyl alcohol was obtained from the polyvinyl ether.

m = 80-99 mol.%,

n = 0.5-15 mol.%,

k = 0-12 mol.%.

The unsaturated radical R ₂ introduced into the side chain contains one or two unsaturated bonds and provides the formation of a spatial structure under conditions of radical polymerization and copolymerization. The radical R ₂ may contain an unsaturated acid residue, for example, acrylic, methacrylic, sorbic, crotonic, cinnamon:

CH ₂ = CH — CO — O—,

CH ₂ = C (CH ₃ ) —CO — O—,

CH ₃ —CH = CH — CH = CH — CO — O—,

CH ₃ —CH = CH — CO — O—,

C ₆ H ₅ —CH = CH — CO — O—,

CH ₂ = C (CH ₃ ) —CO — O — CH ₂ —CH (OH) —CH ₂ —O—,

CH ₂ = CH — CO — O — CH ₂ —CH (OH) —CH ₂ —O—,

CH ₂ = CH — CH ₂ —O — CH ₂ —CH (OH) —CH ₂ —O—

or an alkene group, for example,

CH ₂ = CH-O-,

CH ₂ = CH = CH ₂ —O—,

CH ₂ = CH — O — CH ₂ —CH ₂ —O—.

The unsaturated group may also be introduced as a side acetal substituent.

The degree of crosslinking of PVA affects the physical and functional properties of the material. The number of groups with multiple bonds contained in the polymer side chain is sufficient to achieve the desired properties, such as the hardness of the resulting gel (soft to hard). However, their number may vary depending on the purpose of the material. So, for example, to increase the strength of the material, the number of such groups in the composition of the polymer can be large, while to increase the ductility of the material, a polymer with a lower degree of substitution can be used.

A significant advantage of the hydrogel production method over traditional hydrogel production methods consisting in the polymerization of low molecular weight monomers, usually toxic, or crosslinking of high molecular weight compounds using crosslinking agents or hard radiation, is that the polymerization of the unsaturated derivative can be carried out in the presence of radical initiators polymerization or by exposure to radiation.

The reaction system and the resulting products in this case do not contain residues of low molecular weight monomers.

The invention can be illustrated by the following examples:

EXAMPLES

Example 1

A portion of a modified polymer based on polyvinyl alcohol composition

(m = 94.4 mol%; n = 4.3 mol%, k = 1.3 mol%, M _w = 25000) weighing 1 g was dissolved by heating in 25 ml of distilled water, 0.01 g was added hydrogen peroxide in 1.5 ml of distilled water, 30 mg of ascorbic acid in 1.5 ml of distilled water was added. The mixture was poured into a split mold. At the end of the reaction, the form was opened, the resulting macroporous hydrogel was washed in 200 ml of hot distilled water. Yield 92%. The modulus of elasticity is 20 kPa.

Example 2

A portion of a modified polymer based on polyvinyl alcohol composition

(m = 88 mol%; n = 10.2 mol%, k = 5 mol%, M _w = 77000) with a mass of 1 g was dissolved in 7.5 ml of distilled water when heated, cooled to room temperature, 0 was added , 06 g of hydrogen peroxide in 1 ml of distilled water, the mixture was evacuated to remove dissolved air, 0.06 mg of ascorbic acid in 0.5 ml of distilled water was added. The mixture was poured into a detachable glass mold, frozen in liquid. At the end of the reaction, the form was opened, the resulting macroporous hydrogel was washed in 400 ml of hot distilled water. The yield of 82%. The modulus of elasticity is 60 kPa.

Example 3

A portion of polyvinyl alcohol (M _w = 40,000, the number of residual polyvinyl acetate units 1.32 mol%) weighing 10 g was dissolved in 80 ml of dimethylformamide. The solution was cooled to 130 ° C, 2 g of glycidyl methacrylate in 20 ml of dimethylformamide was added and stirred while heating under nitrogen atmosphere.

Upon completion of the process, the reaction system was cooled. The polymer was planted in acetone. The precipitated polymer was reprecipitated twice from water to acetone. It was then dried in vacuo at room temperature to constant weight. Yield 78%, content of substituted units 4.3 mol.%.

A sample of a modified polymer based on polyvinyl alcohol with a composition weighing 1 g was dissolved by heating in 25 ml of distilled water, cooled to room temperature, 0.06 g of potassium persulfate in 1.5 ml of distilled water was added, the mixture was evacuated to remove dissolved air and cooled to a temperature 5 ° C, 30 μl of N, N, N ′, N′-tetramethylethylenediamine was added. The mixture was poured into a pre-chilled detachable glass mold, frozen and kept for 6 hours at a temperature of -15 ° C. At the end of the reaction, the form was thawed, opened, the resulting macroporous hydrogel was washed in 200 ml of hot distilled water, and then freeze-dried. Yield 92%. Total porosity 64%, average pore size 25.4 μm.

Example 4

A portion of polyvinyl alcohol (M _w = 40,000, the number of residual units of polyvinyl acetate 5.4 mol.%) Weighing 10 g was dissolved by heating in 75 ml of N-methylpyrrolidone, cooled to a temperature of 80 ° C, 2 g of methacryloyl chloride in 25 ml of N-methylpyrrolidone was added and stirred under heating in a nitrogen atmosphere.

Upon completion of the process, the polymer was planted in ethanol. The precipitated polymer was dissolved in water and purified by dialysis, and then freeze-dried. Yield 82%, content of substituted units 5.2 mol.%.

A weighed portion of a modified polymer weighing 1 g was dissolved in 7.5 ml of distilled water when heated, cooled to room temperature, 0.06 g of hydrogen peroxide in 1 ml of distilled water was added, the mixture was evacuated to remove dissolved air and cooled to 5 ° C, was added 0.06 mg of ascorbic acid in 0.5 ml of distilled water. The mixture was poured into a pre-chilled detachable glass mold, frozen in liquid nitrogen and kept at -15 ° C for 12 hours. At the end of the reaction, the form was thawed, opened, the resulting macroporous hydrogel was washed in 200 ml of hot distilled water, then washed three times with 100 ml of ethanol, and then dried in vacuum to constant weight. Product yield 72%. The total porosity of 54%, the average pore size of 16.3 microns.

Example 5

A portion of polyvinyl alcohol (M _w = 25000, the number of residual units of polyvinyl acetate 1 mol%) weighing 10 g was dissolved in 100 ml of water, concentrated hydrochloric acid was added dropwise to a pH of 1.3-1.5. At room temperature, with vigorous stirring, 8 ml of glycidyl acrylate was added dropwise over 8 hours.

At the end of the process, the polymer was planted in acetone. The precipitated polymer was reprecipitated twice from water to acetone. It was then dried in vacuo at room temperature to constant weight. Yield 67%, content of substituted units of 2.7 mol%.

A portion of the modified polymer 1 g was dissolved by heating in 11 ml of distilled water, cooled to room temperature, 0.06 g of hydrogen peroxide in 1 ml of distilled water was added, the mixture was cooled to 5 ° C, 30 μl of N, N, N 'was added, N'-tetramethylethylenediamine. The mixture was poured into a pre-chilled detachable glass mold, frozen in liquid nitrogen and kept at -10 ° C for 8 hours. At the end of the reaction, the form was thawed, opened, the resulting macroporous hydrogel was washed in 200 ml of hot distilled water, and then freeze-dried. Product yield 85%. The total porosity of 74%, the average pore size of 36.1 microns.

The proposed immersion medium has significant advantages over its predecessors:

- for the use of the environment does not require additional devices (bath-rings);

- the medium is installed on the skin of closed eyelids, which excludes contact with the front surface of the eye (conjunctiva and cornea), which reduces the possibility of complications;

- the use of the medium does not require anesthesia;

- the medium is a dense, elastic, flexible substance that retains its shape throughout the study and conducts an echographic signal well;

- the proposed system is easily simulated;

- the system can be used both once and used for repeated studies, since it is easily sterilized by autoclaving or processing with disinfectants;

- various substances (perfumes, antibiotics, etc.) can be added to the system.

The thickness of the products and the shape of the products of this material largely depends on the desired use and can vary widely.

The material of the present invention may optionally further comprise water-based perfumes, medicinal and antiseptic substances that are introduced during the manufacture of the material or applied directly to the finished material.

The material is chemically resistant and biologically inert, sterilized in an autoclave, the surface is smooth and highly elastic.

The method using the proposed immersion medium is as follows: after removal from the conjunctival cavity of the eye prosthesis, the patient is placed in a supine position. Studies are performed on ultrasound diagnostic systems of general clinical purpose with a volume scan mode, for example, on a Voluson - 730 instrument. An immersion medium is installed on the surface of the studied orbit (closed eyelids). The ultrasound transducer is moved along the surface of the medium in the desired direction until a clear visualization of the orbital structures on the monitor is obtained. Using the volumetric scanning mode, an image of the orbital structures and a clear visualization of the implant and its boundaries are obtained. Volumetric modeling of the implant is performed, its volume is calculated. The structure of the implant is also evaluated by the presence of vascularization of the implant, its density. With a decrease in the volume of the eyeball (subatrophy, microphthalmos), the study is carried out by the same method with visualization of the structures of the eyeball, its borders and the state of the soft tissue contents of the orbit.

The method is as follows: after removal of the ocular prosthesis from the conjunctival cavity (in the presence of anophthalmos and microphthalmos), if the cavity is not prosthetic (subatrophy of the eye), the patient is placed in a supine position. The study is performed on ultrasound diagnostic systems of general clinical purpose, for example, on a Voluson-730 instrument.

On the surface of the studied orbit (closed eyelids) without prior local anesthesia, a disk (immersion medium) with a thickness of 4-6 mm and dimensions corresponding to the entrance to the orbit is installed. The scanning ultrasonic sensor is moved along the surface of the disk in the desired direction until a clear visualization of the orbital structures on the monitor is obtained. Using the volumetric scanning mode, an image of the orbital structures, a clear visualization of the musculoskeletal stump, implant, its borders are obtained. Volumetric modeling of the stump is carried out, its volume, size, shape are calculated. The structure of the implant is also assessed by the presence of its vascularization, density in various zones, encapsulation; in cases of the formation of a shell (capsule) around it. Changes in echographic density (densitometric indices) indicate the presence of implant germination by connective tissue.

Thanks to this study, it is possible to determine the parameters of the ocular prosthesis, which is determined by measuring the distance between the back surface of the eyelids and the front surface of the stump.

In cases of subatrophy of the eye, it is possible to determine the echographic density of retrobulbar fiber, the presence and condition of blood flow in a pathologically altered eye. This allows us to judge the severity of the process, the advisability of maintaining the subatrophic eye, as a cosmetic organ. As a rule, a similar study is performed on the pair side to clarify the degree of deviation of the indicators from the norm.

This study is performed at various times after surgery: for example, after 6, 12 months. and in more remote terms (5-10 and more years).

Ultrasonic spatial volumetric imaging allows you to analyze the state of the implant and surrounding orbital tissues using the image received on the monitor in real time. It also seems possible to archive information and further process it without requiring the presence of a patient.

The presented method examined 56 patients in the long term after enucleation.

Studies have shown that this method is simple to implement and quite informative. The proposed tool promotes maximum information.

The data obtained using the proposed method allow us to evaluate the effectiveness of surgical treatment, conduct dynamic monitoring of the condition of the orbital implant and surrounding tissues, and also predict.

Clinical examples.

A 37-year-old patient S. was operated on for keratoconus in 1996, after severe contusion injury to this eye in 2001, the blind eye was enucleated with stump formation by local tissues due to signs of irritation and pain. After 8 years, the formation of the musculoskeletal stump with the help of "Karbotekstim" was made. The patient uses a standard prosthesis of a 2-ellipsoid shape, the retraction of the orbit-palpebral groove is about 2.0 mm, the total mobility of the prosthesis is 70 °. The stump is located in the center of the cavity, its mobility is 90 °. For volumetric ultrasound imaging, the patient’s orbits were laid on their backs and 5.5–6 mm thick disks were installed on closed eyelids without local anesthesia and the size corresponding to the entrance to the orbit was 2.5 × 3.5 cm. The scanning ultrasonic sensor was moved until a clear image was obtained on the monitor of the orbit structures. Ultrasonic spatial visualization made it possible to analyze the state of the implant and surrounding tissues from the obtained image in three real-time scanning planes.

Patient B., 16 years old, with a diagnosis of congenital microphthalmus of the right eye, is prosthetized from 9 months of age. On examination, the eyes are reduced in size. For volumetric echography of the orbit, the patient was placed on his back and a closed disk was installed on closed eyelids without local anesthesia with a thickness of 4.5 mm and a size corresponding to the entrance to the orbit of 2.4 × 3.0 cm. The scanning ultrasonic sensor was moved to obtain a clear image on the monitor structures of the orbit. It was determined: PZO - 10.4 mm, the orbit depth was 19.3 mm, the volume of retrobulbar fiber was 0.56 cm ³ and its density was 65-74-75 ye, the eyeball is deformed, inactive, in the vitreous body fibrous changes, the media do not differentiate . On the side of the healthy eye, the PZD is 22.6 mm, the orbit depth is 22.7 mm, the volume of retrobulbar fiber is 2.01 cm and its density is 90-110-152 ye Thus, a significant decrease in the depth of the orbit and a decrease in the volume and density of retrobulbar fiber are noted on the side of microphthalmus, which indicates a long process with a violation of trophic soft tissues and a decrease in the parameters of the bone orbit.

Thus, the proposed method of orbital ultrasound imaging using a new immersion medium allows, without additional anesthesia, the risk of complications, to evaluate the effectiveness of surgical treatment, conduct dynamic monitoring of the state of the orbital implant and surrounding tissues, and also predict the need for corrective plastic surgeries during the development of anophthalmic syndrome. In cases of reduction of the eyeball in volume, changes in the structures surrounding the eye, it is possible to determine the dynamics of the course of subatrophy, the need for conservative and surgical treatment, its timing; determination of indications for removal of the eyeball and eye prosthetics with the choice of the optimal prosthesis in terms of size and shape.

Claims (2)

1. Immersion medium for volumetric echography of the orbit during anophthalmus and subatrophy of the eye, characterized in that it is a cross-linked polymer hydrogel based on a modified polyvinyl alcohol of the general formula:

where R is H
R ₁ is OH,
R ₂ is an unsaturated group,
R ₃ - O-CO-R ₄ ,
R ₄ is CH ₃ or a residue of another acid from which polyvinyl alcohol was obtained from the polyvinyl ether,
m = 80-99 mol.%,
n = 0.5-15 mol.%,
k = 0-12 mol.%. 2. A method of conducting volumetric echography of the orbit during anophthalmus and subatrophy of the eye, characterized in that the immersion medium according to claim 1 is used in the form of a disk 4-6 mm thick, the size corresponding to the entrance to the orbit, and laid on the front surface of the closed eyelids.