The method of implantation of the drainage valve to normalize intraocular pressure

The method of implantation of the drainage valve to normalize intraocular pressure

The invention relates to medicine, namely to ophthalmology, and is intended for the treatment of all types of refractory glaucoma. The valve is installed, in particular, the Ahmed valve, behind the equator line of the eye, beyond the area of ​​the eyelids, on the back side of the eyeball. Then spend the thread for sewing valve through the sclera for the equator of the eyeball. Bring the ends of the thread out of the sclera.

Thread the ends of the thread into the holes of the valve base. Pull the ends of the thread, setting the valve in a pre-selected location. Then tighten the thread, lowering the valve to the selected location. Secure the thread, firmly fixing the valve. The method provides normal eye movement and adherence of the eyelid to the eye, eliminates the feeling of discomfort and cosmetic defects. The method allows you to accurately install the valve in the selected place, without its displacement during installation.

The invention relates to the field of medicine, namely, eye microsurgery, and can be used to treat all types of refractory glaucoma when installing a valve drainage system to compensate for intraocular pressure.

Known installation methods (implantation) of the drain valve to compensate Ahmed intraocular pressur tions, of which, as the closest analogue.This method includes the following operations:

– preliminary selection of the future location of the drainage valve between adjacent straight muscles of the eye and its front edge 8-10 mm from the limbus of the eye;

– installation of the valve in the selected location directly on the sclera in the pocket. To install the valve in the pocket, the latter is formed in the upper tissues of the patient’s eyeball as follows:

– perform the incision of the conjunctiva along the limb to the width of the valve;

– carry out the detachment of the conjunctiva along the incision line and along the adjacent rectus muscles for a length equal to the sum of the valve length and the distance from the front edge of the valve to the limbus of 8-10 mm by bluntly separating the tenon capsule from the sclera, followed by installing the valve into the resulting pocket and fixing it seam through the holes in the front of the valve base.

Next, perform

– fastening the valve in the place of its installation by hemming the valve through two front openings in the front part of the valve base to the sclera with a nylon thread;

– preparation of the donor scleral flap or flap from the patient’s sclera for the installation of the tube in the area of ​​its insertion into the anterior chamber of the eye. When using the patient’s sclera, a U-shaped incision of the scleral sheet is performed with the base located at the limbus 6 mm long and 4 mm wide;

– vcol needle 23G in the anterior chamber of the eye parallel to the iris through the area of ​​the trabecula, followed by installing the free end of the valve tube into the formed channel for a length of 2-3 mm, while the free end of the tube is performed with a bevel in 30 ° -45 ° relative to its axis;

– the imposition and straightening of the patient’s scleral flap or donor flap 1 × 1 cm in size on the tube;

stitching the expanded scleral donor flap to the sclera of the eyeball at four points along the edges of the patient’s flap or flap along parallel branches of the U-shaped incision. The patient’s U-shaped scleral flap is used when the donor sclera is unavailable;

– after applying a donor flap or a patient flap to the patient’s flap tube, the delaminated part of the upper pocket tissue is fully tensioned onto the flap and its tube, covered with a flap, to the point of incision of the conjunctiva, followed by stitching along the entrance to the pocket in the incision at the limbus.

After installing a valve with a drainage tube, the increased intraocular pressure opens the valve, and excess fluid from the anterior chamber of the eye enters the surrounding valve- space, reducing this pressure.

With all the progressiveness of the described method of implantation of a drainage valve, it has several disadvantages.

First, a filtration “bubble” is formed in the percolated space, filled with fluid that has elapsed from the anterior chamber. Placing the valve close to the limbus causes a close placement of the “bubble” to the limb – in front of the eyeball, which limits the mobility of the eye and can cause strabismus in the patient and diplopia (the appearance of a double image).

Secondly, the proximity of the bubble to the area of ​​the eyelid abutment to the eye disrupts its normal fit, and the surface of the eyeball is unevenly moistened with a tear; disrupting the process of cleansing the surface of the eyeball from the smallest foreign particles caught in the eye. The patient has a feeling of discomfort, a feeling of a foreign body. Possible erosion of the conjunctiva and cornea.

Thirdly, because of the location of the “bubble” in the front of the eyeball, cosmetic defects appear, which are expressed in the fact that the patient has a filtering bubble.

Fourthly, because of the narrowness of the valve location when it is fixed on the sclera and when the “bubble” increases towards the limb, the risk of perforation of the sclera increases, which can cause postoperative complications such as hemophthalmia , internal infection of the eye, retinal detachment.

Fifthly, when the valve is sewn, it often happens that it shifts relative to the initial calculated position of its installation, which increases the time it takes to install the valve and causes additional injury to the eye tissue of the patient. Reducing the distance between the limb and the valve in comparison with the previously planned displacement from the limb of 8-10 mm will additionally aggravate the problems mentioned above.

The objectives of the invention are the normalization of eye movement, ensuring normal adhesion of the eyelid to the eye, eliminating discomfort and cosmetic defects, reducing the likelihood of postoperative complications such as strabismus, diplopia, erosion of the conjunctiva and cornea, hemophthalmia , internal infection of the eye, rupture and detachment of the retina, displacement of the valve tube .

Another task is to precisely set the valve to the selected location, without displacing it during installation.

Tasks are solved by the method of implantation of a drainage valve for the normalization of intraocular pressure, at which the

– preliminary selection of the future location of the valve at a distance from the limb,

– the valve is installed in the selected location and

– fix it by sewing it through the holes in the base of the valve to the tissues of the eye.

The difference of the proposed method from the prototype is the choice of the location of the valve behind the line of the equator of the eye, beyond the eyelids, so that the front edge of the valve is at a distance of no more than 12 mm from the limbus, on the back side of the eyeball, almost at a distance of 12-16 mm.

Then, the installation of the thread of sewing the valve to the sclera in the preselected place, i.e. beyond the equator of the eyeball, with the output of the ends of the filament outside the sclera. After that, the ends of the thread are threaded into the holes of the valve base and by tightening both ends of the thread, the valve is precisely set in the preselected place.

The ends of the thread are tightened, gradually lowering the valve to the chosen place, fix them, rigidly fixing the valve on the calculated place, at a distance of its front edge no closer than 12 mm from the edge of the limb, behind the line of the equator of the eyeball. Such installation of the valve will exclude its displacement from the calculated place.

Ahmed ™ valve manufactured by New World Company was used as a drain valve. Medical, Incorporated, USA.

The method of implantation in accordance with the invention and the above photographs with the imposition of a scleral patient flap on the valve tube is carried out as follows.

First, a conjunctival incision is made along the limb to the width of the valve, with the length of the incision being made with some tolerance for free valve installation in order to prevent excessive tissueinjury . Conjunctival detachment is carried out along the incision line and along adjacent rectus muscles for a length equal to the sum of the distance from the front edge of the valve to the limbus not less than 12 mm and the length of the valve. The detachment is carried out by blunt separation of the tenon capsule from the sclera.

Next, measure the length of the future incision in the sclera from the limbus for the subsequent installation of the drainage tube of the valve and carry out this incision to form the scleral flap of the patient. To install the valve, put the U-shaped suture outside the equatorial line of the eyeball in that place so that the valve with its front part is installed at a distance from the limb not closer than 12 mm, practically at a distance of 12-16 mm from the limb, with the output both ends of the thread beyond the sclera. Next, the Ahmed valve is activated by washing it with saline, for which purpose 1 ml saline is injected into the drainage tube and the valve through the blunt cannula 28G with filling thevalve tube with it.

An activated flap is placed into the formed pocket, orienting its leading edge towards the limb and the holes to the location of the free ends of the thread. The ends of the thread are threaded into the holes in the base of the valve and by tightening the ends of the thread, precisely placing the valve in the pocket with its front part at a distance from the limb of at least 12 mm. The valve is rigidly fixed with the ends of the thread at the sewing point .

The drainage tube is cut at an angle of 30-45 ° for a length of 2-3 mm, sufficient to enter it into the anterior chamber of the eye to the required depth. Into the anterior chamber of the eye in the area of ​​the scleral flap, under its flap, a needle 23G is injected, parallel to the iris through the area of ​​the trabeculae, followed by installation of the free end of the valve tube into the resulting channel 2-3 mm long.

Then the tube is covered with a scleral flap, straightening it, and several seams of the scleral edge of the flap are connected , while fixing the tube under the scleral flap. After applying a scleral flap to the valve tube and fixing it, the peeled off upper part of the pocket is fully tensioned onto both the valve and its tube fixed with a scleral flap with sutures to the incision of the arch, covering both the valve and the tube fixed with sutures. Next, two stitches are placed at the extreme points of the conjunctival incision .

After installing a valve with a drainage tube with excessive intraocular pressure through the drainage tube and the valve membrane, excess fluid from the anterior chamber of the eye enters the peristallapedspace.

In space patient body is formed flat, diffuse filtration airbag “A” ( “bubble”) as a reservoir in spaces. Subconjunctival channels of outflow of intraocular fluid will be formed in the filtration cushion, ensuring a reduction in intraocular pressure and its normalization. The cushion will provide gradual resorption and evacuation of the fluid through the sutenone formedthreads.

By installing the valve behind the equator line of the eyeball, the filtration pad will also be located behind the equator line (FIG. 14), behind the eyelid line, without interfering with normal eye mobility, ensuring that the eyelid performs its functions of uniformly wetting the eye surface, cleansing it, without causing discomfort and cosmetic problems in the patient, as well as postoperative complications.

After installing the valve, a constant outflow of fluid is ensured at a constant rate of 12 µl / min with the maintenance of intraocular pressure not exceeding 18 mm Hg. Installing the valve further from the limbus of the eye in comparison with the prototype, at a distance of at least 12-16 mm, outside the equator of the eye does not interfere with the work of the rectus muscles and eye movement.

Normal operation of the muscles will not cause complications in the form of strabismus, eliminate the unpleasant sensations of the presence of a foreign body in a patient, and will not lead to cosmetic defects.Installing the valve by the proposed method by preforming the U-shaped seam with the output of the thread end beyond the sclera, threading the ends of the thread into the holes for the valve base intended for them, fixing the valve by tightening the free ends of the thread of the U-shaped seam, then fixing them to the valve to the chosen place without displacement of the valve from the intended place in the process of its fixation.

The method has passed clinical trials, as a result of which more than a hundred patients were diagnosed with secondary neovascular diagnoses post – thrombotic glaucoma, absolutely aching glaucoma, primary open – angle glaucoma from the first to the fourth stages. The observation period was up to three months. In all patients, intraocular pressure returned to normal, patients did not feel any discomfort.Cosmetic defects in patients operated on in accordance with the invention and postoperative complications were not observed. The emerged filtration bubble behind the equatorial line of the eye did not interfere with the movement of the eye and the eyelid.

 

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