RU2833861C1 - Method for ahmed antiglaucoma valve implantation in patients after vitrectomy - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medicine, namely to ophthalmology, and can be used for implantation of antiglaucoma valve Ahmed in patients with secondary glaucoma after vitrectomy. That is ensured by a conjunctival incision in an upper external quadrant along a limb. Conjunctival flap is formed between two rectus oculomotor muscles. Then Tenon's capsule is cut off from episclera to form a conjunctival pocket. Valve body is placed in the formed conjunctival pocket and the valve body is fixed to the sclera. L-shaped scleral flap is cut out with base to limb with size of 6 mm by 3 mm in the area free from scleral scars. Paracentesis is performed at 9 o’clock. After that, 0.2 ml of viscoelastic is introduced into the anterior chamber. Valve body is cut off and implanted into the anterior chamber. Scleral flap is closed with 4 interrupted sutures along the edges. Further, at 1 mm from the limb, the valve tube together with the scleral flap is covered with a donor material measuring 6 mm by 8 mm and fixed with 4 interrupted sutures. Then Tenon's capsule is pulled in the tube projection and fixed with two interrupted sutures. Conjunctival incision is sealed with two interrupted sutures to limb.

EFFECT: invention enables achieving stable compensation of intraocular pressure, preserving the surgically formed outflow tracts of intraocular fluid, as well as reducing the rate of postoperative complications.

1 cl, 1 ex

Description

The invention relates to the field of medicine, namely to ophthalmology, and can be used for implantation of the Ahmed antiglaucoma valve in patients with secondary glaucoma after vitrectomy.

Retinal surgery has improved significantly with the introduction of closed systemic vitrectomy in the 1970s. Over time, the indications for vitrectomy have expanded significantly. Complications that developed with the increasing number of postoperative patients have begun to be studied, and one of the most important of these is secondary glaucoma. Intraocular pressure (IOP) values above 30 mmHg have been found in 35% of patients who underwent pars plana vitrectomy. The increase in IOP has been reported to be surgically and tamponade- and responsive to antiglaucoma treatment and is usually temporary. Elevated IOP after vitrectomy that cannot be reduced by medication requires surgical intervention. Ahmed valve implantation is an effective surgical method for lowering IOP in patients with glaucoma after vitrectomy. The Ahmed valve provides a sophisticated mechanism to control the outflow of aqueous humor into the sub-Tenon's space.

The Ahmed valve consists of thin silicone elastic membranes 8 mm long and 7 mm wide, forming a Venturi chamber. The membranes pre-open and close in response to IOP fluctuations in the range of 8-12 mmHg. After implantation, intraocular fluid (IOF) slowly and continuously flows into the valve chamber. When the pressure reaches a predetermined threshold, the valve opens and releases the IOF into the sub-Tenon space, thereby reducing IOP and maintaining visual function.

The above determines the relevance of implantation of the Ahmed antiglaucoma valve in patients with secondary glaucoma after vitrectomy in order to achieve a hypotensive effect, as well as slow down the loss of visual functions.

A method for implanting the Ahmed valve in refractory glaucoma is known (A novel surgical technique for preventing of Ahmed glaucoma valve tube exposure: Long scleral flap augmented with Tenon advancement and duplication DOI:10.1186/s12886-018-0907-y), which consists of cutting out a conjunctival flap in the superotemporal quadrant of the eye, after which the Ahmed valve is inserted under the conjunctiva and Tenon's capsule and the valve body is sutured to the sclera at a distance of about 10 mm from the limbus with Vicryl 6.0 thread, then a U-shaped scleral flap is cut out with the base towards the limbus, 10 mm long. The valve tube was cut to the required length, allowing it to be inserted into the anterior chamber to a depth of 2-3 mm with a beveled edge. A 23G needle is then inserted into the anterior chamber parallel to the plane of the iris at a distance of 2 mm posterior to the limbus under the scleral flap, after which the valve tube is inserted through the formed opening, avoiding contact with the iris or corneal endothelium, then the scleral flap is sutured with interrupted Neilon 10.0 sutures, then the flap is covered with Tenon's membrane on top, suturing it with interrupted sutures, after which the conjunctiva is fixed to the limbus with interrupted Vicryl 8.0 sutures. At the end of the procedure, a subconjunctival injection of corticosteroids and antibiotics was performed.

Formation of a U-shaped flap over the drainage tube may lead to a high risk of increased filtration at the site of its introduction into the anterior chamber of the eye. In patients after vitrectomy, given the presence of scars at the site of port insertion, it is not always possible to stretch the Tenon membrane so as to completely cover the scleral flap and the valve tube.

Taking into account cicatricial changes in the sclera, Tenon's membrane and conjunctiva in patients after vitrectomy, the method we propose will allow us to achieve strengthening of the antiglaucoma surgery (AGO) zone, a stable hypotensive effect, minimal postoperative complications, and preservation of visual functions.

The objective of the invention is to develop a safe and effective implantation of the Ahmed antiglaucoma valve in patients after vitrectomy, strengthening the AGO zone, reducing the risk of postoperative complications and compensating for intraocular pressure (IOP) in the postoperative period.

The technical result of the proposed method is the implantation of the Ahmed antiglaucoma valve in patients after vitrectomy, which allows achieving stable compensation of IOP, preserving surgically formed pathways for the outflow of intraocular fluid (IOF), and reducing the incidence of postoperative complications.

The method is carried out as follows.

In the operating room, under retrobulbar anesthesia, the patient undergoes a conjunctival incision in the upper outer quadrant along the limbus, after which a conjunctival flap is formed between the two rectus extraocular muscles, then Tenon's capsule is cut off from the episclera to form a conjunctival pocket, the valve tube is washed with saline and viscoelastic, then the valve body is placed in the formed conjunctival pocket and the valve body is fixed to the sclera with two interrupted sutures at a distance of 10 mm from the limbus with non-absorbable silk 8.0 thread, after which an L-shaped scleral flap is cut out with the base to the limbus, measuring 6 mm by 3 mm in the area free of scleral scars, then paracentesis is performed at 9 o'clock, after which 0.2 ml of viscoelastic is injected into the anterior chamber, then the valve tube is cut and implanted into the anterior chamber, then the scleral flap is sutured with 4 interrupted sutures along the edges, then, retreating 1 mm from the limbus, the tube together with the scleral flap is covered with donor material measuring 6 mm by 8 mm and fixed with 4 interrupted sutures, after which Tenon's capsule is pulled in the projection of the tube and fixed with two interrupted sutures, then the conjunctival incision is sealed with two interrupted sutures to the limbus.

This method achieves stable compensation of IOP, preserves surgically formed pathways for the outflow of intraocular fluid (IOF), and reduces the incidence of postoperative complications.

The method is confirmed by the following example.

Patient V., 57 years old. History: increased IOP in the right eye (OD) with the maximum hypotensive regimen was detected during a medical examination at the local clinic in 2021. In February 2023, vitrectomy with endolaser coagulation of the retina with silicone tamponade was performed at the local clinic, combined with cataract phacoemulsification with implantation of an intraocular lens (IOL) in OD for retinal detachment and complicated cataract. One year later, a revision of the vitreous cavity was performed with replacement of silicone with a gas-air mixture. Three months after the operation, an increase in IOP OD was noted - 32 mm Hg according to Maklakov.

On examination OD: Visual acuity (Vis) 0.2 does not correct (n/c). IOP OD according to Maklakov - 34 mm Hg (without hypotensive regimen). Perimetry: corresponds to advanced stage of glaucoma. Biomicroscopy OD: The eye is calm, the cornea is transparent, the anterior chamber is of medium depth, the aqueous humor is transparent, the iris is subatrophic, the IOL is in the capsular bag, in the correct position. Avitria. The optic disc is pale, the disc excavation is 0.8, the borders are clear. The vascular bundle is shifted to the nasal side. The macular zone is unremarkable. Pigmented laser coagulates of the retina along the periphery.

Gonioscopy: the anterior chamber angle (ACA) is open, grade 2 pigmentation. Particles of emulsified silicone oil are visualized in the upper segment.

Diagnosis: OD Secondary uncompensated glaucoma. Pseudophakia. Avitria. Operated retinal detachment. Left eye - initial age-related cataract.

In July 2023, the Ahmed valve was implanted using the proposed method.

In the early postoperative period, there are no peculiarities. At discharge: no complaints; Vis OD 0.2 n/c; pneumotonometry: IOP OD=12 mm Hg without hypotensive therapy. According to ultrasound B-scanning OD - membranes are adjacent. Avitria. At the control examination after 6 months, no negative dynamics were noted during the examination. IOP OD=13 mm Hg (pneumotonometry) without hypotensive therapy. As a result of treatment, the patient achieved stable compensation of IOP, preserved visual functions and slowing down of glaucomatous optic neuropathy.

Claims (1)

A method for implanting an Ahmed antiglaucoma valve in patients after vitrectomy, characterized by cutting out a scleral flap, inserting a valve tube into the anterior chamber to a depth of 2-3 mm, inserting a 23G needle into the anterior chamber parallel to the plane of the iris at a distance of 2 mm posterior to the limbus under the scleral flap, inserting the valve tube through the formed opening, suturing the scleral flap with interrupted sutures, characterized in that an L-shaped scleral flap is cut with the base toward the limbus, measuring 6 mm by 3 mm, which is sutured with 4 interrupted sutures along the edges, then, retreating 1 mm from the limbus, the tube together with the scleral flap is covered with donor material measuring 6 mm by 8 mm, which is fixed with 4 interrupted sutures, after which Tenon's capsule is pulled in the projection of the tube and fixed with two interrupted sutures.