Retinal Detachment - Treatment

Surgical treatment of retinal detachment aims to block retinal tears and remove vitreoretinal adhesions that pull the retina into the vitreous cavity.

All surgical intervention methods used can be conditionally divided into three groups.

Hyper- or hypothermic (photocoagulation, diathermocoagulation, cryopexy), local transpupillary or transscleral effects designed to cause adhesive inflammation in the area of retinal breaks and firmly fix the retina.

Scleroplastic operations (temporary balloon or permanent local, circular or combined scleral buckling in the area of projection of retinal breaks with silicone or biological implants) aimed at restoring contact of the retina with the underlying membranes. A buckle applied from the outside to the sclera presses it inward and brings the outer capsule of the eye and the choroid closer to the detached and shortened retina.

Intravitreal surgeries are surgeries performed inside the eye cavity. First of all, vitrectomy is performed - excision of the altered vitreous body and vitreoretinal adhesions. In order to press the retina to the underlying eye membranes, expanding gases, perfluoroorganic compounds or silicone oil are introduced. Retinotomy is a dissection of the shortened and contracted detached retina with subsequent straightening and fixation of the edges using cryo- or endolaser coagulation. In some cases, microscopic retinal nails and magnets are used. All these surgeries are performed with endoscopic lighting using special manipulators.

A prerequisite for the success of retinal detachment surgeries is their timeliness, since prolonged retinal detachment leads to the death of the optic-nerve elements of the retina. In such cases, even with complete anatomical adhesion of the retina, there is no restoration or improvement of visual functions. Constant careful ophthalmoscopic monitoring is also necessary for reliable blockade of all retinal breaks during surgery. In the absence of contact between the retina and the underlying membranes in the break zone, external or internal evacuation of the subretial fluid and a combination of both episcleral and endovitreal techniques are indicated.

When performing the operation at a modern technical level, it is possible to achieve retinal adhesion in 92-97% of patients. In the early postoperative period, local and general anti-inflammatory therapy is indicated using non-steroidal and steroid drugs, systemic enzyme therapy in the presence of hemorrhages. Subsequently, it is advisable to conduct repeated courses of treatment, including drugs that normalize hemodynamics and microcirculation of the eye. Patients operated on for retinal detachment should be under the dispensary supervision of an ophthalmologist and avoid physical overloads.

Vision prognosis

The main factor responsible for final visual function after successful retinal reattachment is the duration of macular involvement.

• In most cases of retinal detachment involving the macula, preoperative visual acuity is maintained.
• A delay of one week in surgical intervention for retinal detachment without macular involvement does not affect subsequent vision recovery.
• In retinal detachments without macular involvement that last less than 2 months, some deterioration in visual acuity occurs, but there is no direct correlation between the duration of macular detachment and final visual acuity.
• In retinal detachment without macular involvement that lasts more than 2 months, significant deterioration in vision occurs, which is most likely due to the duration of macular involvement.

Principles of scleral buckling

Scleral buckling consists of creating an inward depression of the sclera. The explant is a material that is sutured directly onto the sclera. The main goal is to close the retinal tear by connecting the RPE to the sensory retina; to reduce dynamic vitreoretinal traction in the area of local vitreoretinal adhesion.

Local explants

Configuration

• radial explants are placed at right angles to the limbus;
• Circular explants are placed parallel to the limbus to create a sectoral shaft.

Dimensions: For adequate closure of the retinal tear, it is important that the shaft is accurately positioned, of the correct length, width and height.

• a) the width of the radial ridge depends on the width of the retinal rupture (the distance between its anterior ends), and the length depends on the length of the rupture (the distance between its base and apex). Usually the ridge size is 2 times the size of the rupture. The required width and length of the sectoral circular ridge depend on the length and width of the rupture, respectively;
• b) the height is determined by the following interrelated factors:
  • The larger the diameter of the explant, the higher the shaft.
  • The further apart the seams are, the higher the shaft.
  • The tighter the seams, the higher the shaft.
  • The lower the intraocular pressure, the higher the shaft.

Indications for radial filling

• Large U-shaped ruptures with little likelihood of a fish mouth effect.
• Relatively rear rips for easier suturing.

Indications for sectoral circular filling

• Multiple ruptures localized in one or two quadrants.
• Anterior tears that are easier to close.
• Wide dialysis-type tears.

Circling explants

Dimensions. The most commonly used tape is 2 mm wide (No. 40). The circlage tape creates a fairly narrow ridge, so it is often supplemented with radial jaws or circular strong silicone rims to close large tears. A ridge of 2 mm can be achieved by tightening the filling to 12 mm. The ridge created by circlage fillings (unlike local ones) is permanent.

Indications

• Gaps involving three or more quadrants.
• Degeneration of the "lattice" or "snail track" type involving three or more quadrants.
• Widespread retinal detachment without visible breaks, especially with media opacification.
• After unsuccessful local interventions, in which the reason for the failure remained unclear.

Scleral buckling technique

Preliminary preparation

1. Using conjunctival scissors, a circular incision is made in the conjunctiva with the stenotic capsule near the limbus in the quadrants corresponding to the retinal breaks.
2. The tenotomy hook is inserted under the corresponding rectus muscles, followed by the application of frenal sutures.
3. The sclera is examined to detect areas of thinning or abnormal vortex veins, which may have implications for subsequent suturing and drainage of subretinal fluid.
4. A 5/0 Dacron scleral suture is placed over an area calculated to correspond to the apex of the tear.
5. The tip of the suture is grasped with curved mosquito-type tweezers as close to the knot as possible.
6. In indirect ophthalmoscopy, sclerocompression is performed by turning the tweezers. If the indentation does not coincide with the rupture, the procedure is repeated until the exact localization is achieved.
7. Using a cryo-tip, sclerocompression is carefully performed followed by cryorexia until a blanching area (2 mm) is formed around the rupture.

Local explant suturing

1. Based on the criteria listed above, an explant of the appropriate size is selected.
2. Using a measuring compass, the locations of the sutures are determined and marked on the sclera with a thermal cautery.

NB: As a rule, the distance between sutures should be 1.5 times the diameter of the explant.

3. The explant is sutured using a “mattress” suture.
4. If necessary, subretinal fluid is drained.
5. The position of the break relative to the shaft is checked and, if necessary, the shaft is repositioned.
6. The sutures are tightened over the explant.

Drainage-air-cryo-explant technique

Localization is relatively simple for anterior breaks with low subretinal fluid levels. In bullous retinal detachment, precise localization is quite difficult, especially if the breaks are located postequatorially. In such cases, this technique is most suitable.

1. Subretinal fluid is drained to create contact between the retina (and hence the break) and the RPE.
2. Air is introduced into the vitreous cavity to prevent hypotension caused by drainage.
3. After this, the rupture can be precisely localized with subsequent cryocoagulation.
4. The explant is introduced.

Cerclage procedure

1. Select a tape of the required diameter.
2. One end of the tape is grasped with curved mosquito-type tweezers and placed under the four rectus muscles.
3. The ends of the tape are inserted into the Watzke sleeve according to the original quadrant.
4. The tape is tightened by pulling on the ends so that it lies neatly around the area of the "jag" line.
5. The tape is gently pushed back (about 4 mm) and secured with support stitches in each quadrant.
6. Subretinal fluid is drained.
7. The tape is tightened further to achieve the required height of the indentation shaft under indirect ophthalmoscopy control.

NB: The ideal height is considered to be 2 mm. This can be achieved by reducing the circumference of the tape to 12 mm.

8. The circular depression shaft is created so that the retinal breaks “lie” on the anterior surface of the shaft (i.e. the shaft should be located directly behind the break).
9. If necessary, a radial sponge can be inserted under the band to block a large U-shaped tear or a cerclage band to block multiple tears, making sure that the shaft covers the base of the vitreous anteriorly.

Subretinal fluid drainage

Drainage of the subretinal fluid ensures immediate contact between the sensory retina and the RPE. Most retinal detachments can be treated without drainage, but drainage is necessary in some circumstances. However, it may be associated with potential complications (see below). Not draining may avoid these complications, but then immediate contact between the sensory retina and the RPE is often not achieved, with flattening of the macular area. If contact is not achieved within 5 days, a satisfactory rim around the break does not develop because of decreased RPE density. This leads to retinal non-adherence and, in some cases, secondary "opening" of the break in the postoperative period. In addition, drainage of the subretinal fluid allows the use of internal tamponade agents (air or gas) to form a large bleb.

Indications

• Difficulties in localizing ruptures with bullous fluid separation, especially with transequatorial ruptures.
• Retinal immobility (eg, PVR), since successful surgery without drainage is possible if the detached retina is mobile enough to allow it to reattach in the postoperative period.
• Old retinal detachments, where the subretinal fluid is viscous and may take months to resolve, so drainage is necessary even if the break can be blocked without it.
• Inferior retinal detachments with accompanying equatorial breaks should be carefully drained, since with the patient in an upright position in the postoperative period, the remnants of subretinal fluid may shift downward and provoke a secondary break.

There are no standards for drainage techniques. The two most popular methods are described below.

Method A

• Reducing external pressure on the eyeball by loosening the traction sutures and lifting the eyelid speculum.
• A 4 mm long radial sclerotomy is made just above the area of highest subretinal fluid level; the choroid is inserted into the incision.
• The inserted choroid is perforated along a tangential line using a hypodermic needle on a syringe or a surgical needle on a needle holder.

Method B

• Perforation is performed with a single, rapid, controlled movement directly through the sclera, choroid and RPE using a subcutaneous needle, holding it at an angle at a distance of 2 mm from the tip.
• To prevent hemorrhage in the drainage area, external digital compression is applied to the eyeball until the central artery is occluded and the choroidal vascular network becomes completely pale.
• Compression is performed for 5 minutes, then the fundus is examined; if bleeding continues, compression is repeated for another 2 minutes.

Complications

• Hemorrhages usually associated with perforation of a large choroidal vessel.
• Unsuccessful drainage (eg, with a dry needle tip) may be due to entrapment of intraocular structures in the slit.
• Iatrogenic formation of a tear caused by retinal perforation during drainage.
• Retinal infringement is a serious complication in which further treatment may be unsuccessful,
• The "fish mouth" effect is typical for U-shaped breaks with paradoxical expansion after scleral depression and drainage of subretinal fluid. The break may communicate with the radial fold of the retina, which complicates its blocking. The tactics in this case consist of creating an additional radial shaft and introducing air into the vitreous cavity.

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Intravitreal air injection

Indications

• Acute hypotension after subretinal fluid drainage.
• Fish mouth effect in a U-shaped fracture.
• Radial retinal folds.

Technique

• use 5 ml of filtered air in a syringe with a needle;
• the eyeball is fixed, then the needle is inserted at a distance of 3.5 mm from the limbus through the flat part of the ciliary body;
• during simultaneous indirect ophthalmoscopy without a condenser lens, the needle is directed toward the center of the vitreous cavity and then advanced until it becomes barely visible in the pupil area;
• carefully perform a single injection.

Potential complications

• Loss of visualization of the fundus due to the formation of small air bubbles when the needle is inserted too deeply into the vitreous cavity.
• Increased intraocular pressure when the introduced volume of air is exceeded.
• Damage to the lens by the needle if it was directed forward.
• Retinal damage due to excessive posterior needle direction,

Pneumatic retinopexy

Pneumatic retinopexy is an outpatient procedure in which an expanding gas bubble is injected intravitreally to seal the retinal break and reattach the retina without scleral buckling. Sulfur hexafluoride and perfluoropropane are most commonly used.

Indications are uncomplicated retinal detachments with small retinal tears or a group of tears within two hour meridians located on 2/3 of the upper periphery of the retina.

Technique of operation

• the ruptures are blocked by cryocoagulation;
• _{0.5 ml of 100% SF 6} or 0.3 ml of 100% perfluoropropane is administered intravitreally;
• After the operation, the patient assumes a position so that the rising gas bubble is in contact with the rupture located above for 5-7 days;
• If necessary, cryo- or laser coagulation can be performed around the rupture.

Retinal Detachment - Surgery Errors

Mistakes in the early stages

Most often they are associated with the presence of an unblocked rupture due to errors made before or after surgery.

Preoperative causes. About 50% of all retinal detachments are accompanied by several breaks, which in most cases are located at 90 degrees relative to each other. In this regard, the surgeon must perform a detailed examination to identify all possible breaks and determine the primary break according to the configuration of the retinal detachment. In the case of media opacity or the presence of an IOL, examination of the periphery is difficult, which makes it impossible to identify retinal breaks.

NB: If no breaks are detected at the periphery, then the last option to consider is the presence of a break in the posterior pole, such as a true macular hole.

Reasons related to surgery

• Inadequate dimensions of the created indentation shaft, its incorrect height, incorrect position, or a combination of these factors.
• Fish mouth effect in retinal tear, which may be due to a communicating retinal fold.
• Missed iatrogenic rupture caused by careless drainage of subretinal fluid.

Late stage errors

Recurrence of retinal detachment after successful surgery may be due to the following reasons.

PVR is the most common cause. Estimates of the incidence of PVR vary from 5 to 10%, depending on the individual case and clinical risk factors (aphakia, preoperative PVR, extensive retinal detachment, anterior uveitis, and excessive cryotherapy dose). The force of traction associated with PVR may lead to recurrence of old breaks and formation of new ones. It usually develops between 4 and 6 weeks after surgery. After successful retinal reattachment and an initial period of improvement in visual function, the patient experiences a sudden and progressive deterioration in vision, which may develop within a few hours.

NB: The possibility of postoperative PVR can be reduced in high-risk patients by additional intravitreal administration of 5-fluorouracil and low molecular weight heparin solution during vitrectomy.

1. Recurrence of an old retinal tear without PVR may result from inadequate chorioretinal response or late complications associated with the buckle.
2. New breaks may appear in those areas of the retina that are subject to constant vitreoretinal traction after local buckling.

Complications after surgery

Associated with explant

• A local infection can develop at any time and cause the filling to fail, and in rare cases, lead to orbital cellulitis.
• Rejection of the graft may develop several weeks or months after surgery. Its removal in the first few months after surgery is associated with a risk of recurrent retinal detachment in 5-10% of cases.
• Erosion through the skin is very rare.

Maculopothia

• "Cellophane" maculopathy is characterized by a pathological reflex from the macula and is not associated with changes in the paramacular vessels. Normal visual acuity may be preserved.
• Macular folds are characterized by the presence of a cloudy epiretinal membrane with vascular changes. This complication does not depend on the type, size, or duration of retinal detachment or the type of surgery. In most cases, visual acuity is no higher than 6/18.
• Pigmentary maculopathy is most often the result of an excessive dose of cryocoagulation.
• Atrophic maculopathy usually occurs due to blood leaking into the subretinal space due to hemorrhage from the choroid during surgery. It is seen in surgeries with drainage of subretinal fluid, in which the passage of the needle allows blood to enter the subretinal space.

Diplopia

Transient diplopia often occurs immediately postoperatively and is a favorable prognostic sign indicating adhesion of the macular region. Permanent diplopia is rare, and may require surgery to correct it or an injection of CI bolnlinum toxin. The main factors predisposing to diplopia are:

• Large size of the filling inserted under the rectus muscle. In most cases, diplopia resolves on its own after a few weeks or months and does not require any special treatment, except for the possible use of temporary prismatic glasses. Very rarely, it may be necessary to remove the sponge.
• A tear of the rectus muscle during surgery (usually the upper or lower) when attempting to insert a filling underneath it.
• Rupture of the muscle belly as a result of excessive tension of the frenal sutures.
• Severe conjunctival scarring, usually associated with repeated surgeries, mechanically limits eye movements.
• Decompensation of significant heterophoria, which is a consequence of poor postoperative visual acuity in the operated eye.

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