RU2773143C1 - Method for femtosecond penetrating keratoplasty in patients with keratoglobus - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medicine, namely to ophthalmology. The corneal graft is cut out and placed in the recipient's bed. At the same time, the required initially specified diameter of the main part of the graft is determined in the recipient - 7-8.5 mm. The corneoscleral flap is placed in the artificial anterior chamber of the Ziemer LDV Z8 femtosecond laser (Switzerland). Cutting out the corneal graft disk by laser cutting is carried out in three stages. First, a disk is cut out along the entire circumference to a thickness of 200 microns according to a given diameter of 7-8.5 mm. Then, in the second stage, a ledge with a diameter of 11-12.5 mm with a rectangular cross section is formed by a planar cut with a thickness of 200 mcm. At the third stage, the end-to-end trepanation of the remaining thickness of the corneal graft disk is completed according to the initially specified diameter, the residual sections of the stroma are separated at the laser cut site, and the formed corneal donor graft is separated from the corneoscleral flap. The formation of the graft bed in the recipient is also performed using a femtolaser. First, a disk is cut out along the entire circumference for the entire thickness of the recipient's cornea with a diameter of 7-8.5 mm. Then, by a circular planar cut in the residual peripheral ring of the recipient's cornea, a tunnel is formed in the zone of its maximum thinning along the entire circumference, congruent to the cut protrusion of the graft, to a depth of 200 mcm from the anterior epithelium, 2 mm towards the limbus. The cut corneal disk of the recipient is separated from the residual sections of the stroma and the formed tunnel is opened. After that, the graft is placed in the recipient's bed in such a way that its protrusion is inserted into the tunnel of the recipient's corneal ring. The operation ends with the imposition of a continuous suture or interrupted sutures.

EFFECT: method reduces the frequency of such complications as progressive thinning of the recipient's residual cornea periphery, as well as incongruent comparison of the tissues of the donor's corneal graft and the peripheral residual ring of the recipient's cornea.

1 cl, 3 ex, 3 dwg

Description

The invention relates to medicine, namely to ophthalmology, and can be used for surgical treatment of patients with keratoglobus.

According to modern concepts, keratoglobus is a rare non-inflammatory disease characterized by generalized thinning and globular protrusion of the cornea, followed by the development of ectasic areas, including the formation of a thinning zone in the paralimbal zone around the entire periphery of the cornea, which leads to a violation of its sphericity, a decrease in sharpness. vision and there is a risk of corneal perforation. Non-inflammatory corneal ectasia is a group of diseases characterized by thinning, protrusion, and scarring of the cornea. Keratoglobus constitutes a rarer subset of this group.

Currently, surgical treatment of progressive and advanced stages of keratoglobus is the most effective. Treatment of advanced stages includes UV crosslinking of corneal collagen to stabilize the keratectic process. Surgical treatment of advanced stages characterized by critical thinning, including paralimbal areas of the cornea, is possible only through anterior deep layered or penetrating keratoplasty. One of the features of penetrating keratoplasty in patients with extremely thin corneal periphery is the impossibility of good adaptation of the donor's penetrating corneal graft and the residual periphery of the recipient's stroma resulting from the difference in their thicknesses. Also, the residual peripheral corneal ring of the recipient with genetically determined kerectasia (the so-called graft bed) has the potential for further thinning in the late postoperative period, which leads to a decrease in the functional result of the performed keratoplasty even in the presence of transparent graft engraftment.

The closest analogue is the method of femtosecond penetrating keratoplasty with a combined corneal profile (RF Patent for the invention No. 2424786). At the first stage of the operation, the authors cut out a corneal disc with a combined profile in the donor eye using a femtosecond laser. Intrastromal incisions were made by means of a three-stage resection; first, a posterior lateral corneal incision was made from the anterior chamber to the corneal stroma with an angle of a cylindrical lateral incision relative to the corneal surface of 110–115°, a diameter of 6.3–7.5 mm, and an initial depth of 900–1200 microns, final - 350-370 microns; then a lamellar non-through incision was made in the form of a ring parallel to the anterior surface of the cornea with an outer diameter of 7.8-9.1 mm, an inner diameter of 6.2-7.4 mm, at a depth of 380-400 microns; followed by an anterior lateral incision with an initial depth of 410-430 μm - from the anterior stroma to the epithelial surface of the cornea with an angle of a cylindrical lateral incision relative to the corneal surface of 90°, with a diameter of 7.7-9.0 mm. At the same time, the difference between the inner and outer diameters of the graft was at least 1.5 mm, and the vertical and lamellar incisions partially overlapped each other by 1 mm, the difference between the depth of the incisions was at least 30 μm to improve the separation of the graft along the edges of the cut and optimal matching of tissues donor and recipient. At the second stage, a corneal disc with a combined profile was cut out on the recipient's eye using a femtosecond laser according to the same parameters, only with a change in the initial depth of the posterior lateral incision (600–800 µm), taking into account the pachymetric data of the patient's cornea. At the third stage, the graft was isolated and fixed in the recipient's bed.

The disadvantages of this method of operation include the following:

1. The absence of the effect of stabilization of the keratectic process due to the presence of a residual peripheral ring of the recipient's cornea, which entails a decrease in the functional result in the late postoperative period;

2. Difficulty in adapting a corneal donor graft with increased thickness due to edema due to the presence of the cornea in a conservation medium and the presence of a thinned residual peripheral ring of the recipient's cornea;

3. High rates of postoperative astigmatism due to the lack of congruence of the cut surfaces of the corneas of the donor and recipient.

The objective of this invention is to create a method of modified femtosecond penetrating keratoplasty for the surgical treatment of patients with keratoglobus, avoiding the above disadvantages.

The technical result is a reduction in the frequency of such complications as progressive thinning of the residual peripheral ring of the recipient's cornea, as well as its incongruent comparison of tissues with the donor's corneal graft.

The proposed method of modified femtosecond penetrating keratoplasty for surgical treatment of patients with keratoglobus is as follows.

As a donor material, a corneoscleral flap with a diameter of 16-18 mm is used, previously prepared in a donor eye bank and stored in a conservation medium. Previously, the recipient determines the required primary diameter of the main part of the graft - 7-8.5 mm using a compass or a circular tap. The corneoscleral flap is placed in the artificial anterior chamber of the Ziemer LDV Z8 femtosecond laser (Switzerland). Cutting out a corneal graft disc with a laser cut is carried out in three stages: first, a disc is cut out over the entire circumference over 360 angular degrees for a thickness of 200 μm at a given diameter of 7-8.5 mm, then, at the second stage, a protrusion (“visor” is formed with a planar (longitudinal) cut 200 μm thick) "") with a diameter of 11-12.5 mm with a rectangular cross section 2 mm long; the third stage - through trepanation of the remaining thickness of the disc of the corneal graft is completed along the initially specified diameter, thus obtaining a formed corneal donor graft with a protrusion. Using tweezers and a spatula, the residual sections of the stroma are separated at the site of the laser cut and the formed graft is separated from the corneoscleral flap. The formation of the graft bed in the recipient is also performed using a femtolaser according to a two-stage technique: at the first stage, a disk is cut out around the entire circumference for the entire thickness of the recipient's cornea with a diameter of 7-8.5 mm; at the second stage, by a circular plane cut in the residual peripheral ring of the recipient's cornea, a planar tunnel is formed in the zone of its maximum thinning, along the entire circumference of 360 angular degrees, congruent to the cut protrusion of the graft, to a depth of 200 microns from the anterior epithelium, 2 mm towards the limbus. Using tweezers and a spatula, the residual sections of the stroma are separated and the cut out corneal disc of the recipient is separated, thus opening the formed tunnel in the residual peripheral corneal ring of the recipient. After that, the formed corneal donor graft is placed in the recipient's bed in such a way that the graft ledge is inserted into the tunnel of the recipient's corneal ring. The operation ends with the imposition of a continuous suture or interrupted sutures.

The advantages of the proposed method are the following:

1. Due to the formation of a planar tunnel in the residual peripheral ring of the recipient's cornea and the fixation of the protrusion ("visor") of the transplant of the donor cornea in it, the thicknesses of the transplant and its bed are equalized and the strength properties of the periphery of the recipient's cornea are improved. This leads to a decrease in the likelihood of intra- and postoperative complications and stabilization of the keratectic process;

2. Due to the stabilization of the keratectic process in the residual peripheral ring of the recipient's cornea, the functional result of the operation is maintained throughout the entire period of transparent engraftment and functional activity of the donor graft;

3. Due to the increase in keratopachymetric parameters of the periphery of the recipient's cornea, by fixing an additional donor corneal flap in this area, a congruent comparison of the donor and recipient tissues in the interface area is provided;

4. Due to the congruent comparison of the corneal tissues of the donor and the recipient, a more uniform scar is formed, which increases its strength properties, and also reduces the magnitude of postkeratoplastic astigmatism.

The invention is illustrated by figures 1-3. On FIG. 1 is a cross-sectional diagram of a corneal graft, FIG. 2 shows a diagram of corneal graft matching with the residual peripheral ring of the recipient's cornea, top view, FIG. 3 shows a congruent comparison of the cut graft in the recipient's bed, frontal view.

Position 1 indicates the main part of the donor graft, 2 - protrusion ("visor") of the corneal graft, 3 - peripheral ring of the recipient's cornea, 4 - residual parts of the stroma of the peripheral ring of the recipient.

The method is characterized by the following clinical examples:

Example 1. Patient V., 65 years old, was treated in the hospital of the FGAU NMIC "MNTK" MG "" from 08/04/2021 to 08/10/2021 with a diagnosis of OS Keratoglobus. Visual acuity OS 0.1.

08/05/2021 surgery was performed: OS modified femtosecond penetrating keratoplasty. Modified femtosecond penetrating keratoplasty was performed by the claimed method, while the initially specified diameter of the main part of the graft was 7 mm, a disk was cut around the entire circumference over 360 angular degrees for a thickness of 200 μm at a given diameter of 7 mm, then, in the second stage, a planar cut with a thickness of 200 μm was formed protrusion with a diameter of 11 mm. Complications during the operation and in the postoperative period were not observed. On the first day after the operation, optical coherence tomography of the anterior eyeball was performed, according to which congruent adaptation of the donor corneal graft and recipient tissues was noted. The patient was discharged from the hospital on the 7th day. Uncorrected visual acuity OS=0.1. Visual acuity with maximum correction sph -2.5 cyl -4.5=0.4.

Example 2. Patient K., 39 years old, was treated in the hospital of the FGAU NMIC "IRTC" MG "" from 08/08/2021 to 08/14/2021 with a diagnosis of OS Keratoglobus. Visual acuity OS 0.1.

08/09/2021 surgery was performed: OS modified femtosecond penetrating keratoplasty. Modified femtosecond penetrating keratoplasty was performed by the claimed method, while the initially specified diameter of the main part of the graft was 8.5 mm, the disc was cut around the entire circumference over 360 angular degrees for a thickness of 200 μm at a given diameter of 8.5 mm, then the second stage was a planar cut 200 µm thick formed a protrusion with a diameter of 12.5 mm. Complications during the operation and in the postoperative period were not observed. On the first day after the operation, optical coherence tomography of the anterior eyeball was performed, according to which congruent donor corneal graft and recipient tissues were noted. The patient was discharged from the hospital on the 7th day. Uncorrected visual acuity OS=0.2. Visual acuity with maximum correction sph -1.5 cyl -4.0=0.5.

Example 3. Patient N., 37 years old, was treated in the hospital of the FGAU NMIC "IRTC" MG "" from 08/08/2021 to 08/14/2021 with a diagnosis of OD Keratoglobus. Visual acuity OD 0.1.

09/09/2021 surgery was performed: OD modified femtosecond penetrating keratoplasty. Modified femtosecond penetrating keratoplasty was performed by the claimed method, while the initially specified diameter of the main part of the graft was 7.5 mm, the disk was cut around the entire circumference over 360 angular degrees for a thickness of 200 μm at a given diameter of 7.5 mm, then the second stage was a planar cut 200 µm thick formed a protrusion with a diameter of 11.5 mm. Complications during the operation and in the postoperative period were not observed. On the first day after the operation, optical coherence tomography of the anterior eyeball was performed, according to which congruent adaptation of the donor corneal graft and recipient tissues was noted. The patient was discharged from the hospital on the 7th day. Uncorrected visual acuity OD=0.1. Visual acuity with maximum correction sph -2.0 cyl -4.0=0.5.

A total of 4 operations were performed in patients with a diagnosis of keratoglobus.

Claims (1)

A method for femtosecond penetrating keratoplasty in patients with keratoglobus, including cutting out a corneal graft and placing it in the recipient's bed, characterized in that the recipient first determines the required primary diameter of the main part of the graft - 7-8.5 mm, the corneoscleral flap is placed in an artificial anterior chamber using a Ziemer LDV Z8 femtosecond laser (Switzerland), cutting out the corneal graft disk by laser cutting is carried out in three stages: first, the disk is cut out over the entire circumference to a thickness of 200 μm at a given diameter of 7-8.5 mm, then, in the second stage, a protrusion with a diameter of 200 μm is formed with a planar cut 11-12.5 mm with a rectangular cross section; at the third stage, according to the initially specified diameter, end-to-end trepanation of the remaining thickness of the corneal graft disk is completed, the residual sections of the stroma are separated at the site of the laser cut, and the formed corneal donor graft is separated from the corneoscleral flap; the formation of a bed for the transplant in the recipient is also performed using a femtolaser: first, a disk is cut out around the entire circumference for the entire thickness of the recipient's cornea with a diameter of 7-8.5 mm; then, by a circular planar cut in the residual peripheral ring of the recipient's cornea, a tunnel is formed in the zone of its maximum thinning along the entire circumference, congruent to the cut protrusion of the graft, to a depth of 200 μm from the anterior epithelium, 2 mm towards the limbus, the cut corneal disc of the recipient is separated from the residual sections of the stroma and open the formed tunnel, after which the graft is placed in the recipient's bed so that its protrusion is inserted into the tunnel of the recipient's corneal ring; the operation is completed with the imposition of a continuous suture or interrupted sutures.

Images