Rhegmatogenous Retinal Detachment (RRD) Treatment & Management

Since the late 1990s, there has been a generalized trend in favor of PPV over SB and PR as the primary treatment modality of RRD. ^[17]

No role exists for medical care in the treatment of rhegmatogenous retinal detachments (RRDs).

There are several methods of treating a rhegmatogenous retinal detachment (RRD), including pneumatic retinopexy, scleral buckling (SB), and pars plana vitrectomy (PPV). ^{[18, 19]} ​Regardless of the surgical technique chosen, the surgical goals are to identify and close all the breaks with minimum iatrogenic damage and to reduce vitreoretinal traction. Closure of the breaks occurs when the edges of the retinal break are brought into contact with the underlying RPE. This is accomplished either by bringing the eye wall closer to the detached retina (a scleral buckle) or by pushing the detached retina toward the eye wall (intraocular tamponade with a gas bubble), pars plana vitrectomy, or a combination of these techniques. Sealing of the breaks is accomplished by creating a strong chorioretinal adhesion around the breaks; this may be completed with trans–partial-thickness scleral diathermy, transscleral cryotherapy, or laser photocoagulation.

During diathermy, an alternating electrical current of 13.56 MHz is generated. As the current passes through the tissue, resistance of the tissue gives rise to heat. This heat coagulates the tissue. Diathermy produces an adequate RPE adhesion, but it produces immediate scleral shrinkage with subsequent scleral necrosis. This leads to complications during reoperations and an increased rate of scleral abscess formation. Diathermy generally is used during implant procedures and applies to partial-thickness sclera.

Cryotherapy avoids all the complications of diathermy. However, it breaks down the blood-ocular barrier and may cause dispersion of RPE cells into the vitreous cavity, which may contribute to PVR. Following cryotherapy, the retinal RPE adhesion usually is weaker during the first week, but, by the end of the second week, the adhesion attains its strongest strength.

Laser photocoagulation causes the least morbidity. However, it requires the retina to be flat over the RPE before a chorioretinal adhesion can be formed. The adhesion attains its maximum strength at 7 days.

Scleral buckles usually are made of solid silicone and silicone sponges. Other materials, such as fascia lata, gelatin, and preserved sclera, have been used at different times for scleral buckling.

Scleral explant

Initially, Custodis described this technique, which Lincoff later modified. ^{[20, 21]}

A conjunctival peritomy is performed with isolation of the recti muscles.

Indirect ophthalmoscopy is used to localize all the breaks. Once the breaks are localized, they usually are treated with cryotherapy.

A buckling element is chosen and sutured over the breaks. Visualization for these cases typically involves surgical loupes. Several authors have described the use of a microscope coupled to endoillumination with the wide-angle viewing system for visualization. In 1 of the largest series to date, Frisina et al reported the effectiveness and safety of this technique. ^[22]

The surgeon decides whether to drain the subretinal fluid. The buckle is adjusted to an appropriate height. The central retinal artery is monitored carefully during this maneuver.

In cases where the subretinal fluid is not drained, an anterior chamber paracentesis and/or liquid vitreous removal is performed to allow tightening of the buckle without markedly increasing intraocular pressure.

Postoperative visual acuity seems to show a worse prognosis if the repair is performed after 6 days of a macula-off RRD.

Traditionally SB has been performed under indirect ophthalmoscopy. Visualization under indirect ophthalmoscopy may be fraught with difficulties, particularly in cases where the pupil is small; in pseudophakic eyes with posterior capsular opacification; or when the breaks are too small to be identified. ^[19]  In 2012, Aras and colleagues ^[23]  introduced the concept of SB under non-contact wide angle visualization. In their series of 16 eyes, 13 (81%) attained retinal re-attachment. Non-contact wide-angle fundus visualization increases the field of view up to 130° and the view is not too dependent on pupil size. ^[24]  Since then, several groups have reported on the outcomes of non-contact wide-angled visualization with chandelier-assisted scleral buckling for primary uncomplicated RRD. ^{[19, 25, 26]} A retrospective case series of 282 eyes that underwent non-contact wide-angled visualization with chandelier-assisted SB (mean follow-up, 13.5 months) reported that the single operation anatomic success rate was 85.1% (240/282), which compared favorably with conventional SB. ^[19]  The main advantage of this technique is the improved visualization even through small pupils. Better visualization ensures treatment of all breaks while avoiding excessive treatment and ensures safer placement of intrascleral sutures for scleral fixation of the buckling element. The improved visualization and magnification afforded by non-contact wide-angled visualization with chandelier-assisted SB lends itself as an improved platform for teaching aspiring vitreoretinal surgeons. The main disadvantage of the procedure is the cost involved with the chandelier and the need to have a microscope with a wide angle viewing system.

Intrascleral implant (Mostly of historical interest only, since very few surgeons use it)

Schepens popularized this method. ^[27]

A conjunctival peritomy is performed with isolation of the recti muscles.

Indirect ophthalmoscopy is used to localize all the breaks. A partial lamellar scleral resection is performed in the area of the breaks.

Diathermy applied to the residual partial-thickness scleral bed is used to create a chorioretinal adhesion.

A scleral implant is chosen and put in the bed of the dissected sclera.

Drainage of the subretinal fluid is undertaken.

The sclera is sutured over the implant. An encircling element may be placed around the equator of the eye to maximize the scleral buckle and to further reduce vitreoretinal traction by decreasing the eye's equatorial diameter. This will cause some degree of axial myopia by lengthening the globe.

Drainage versus no drainage

The drainage of the subretinal fluid is a controversial topic among vitreoretinal specialists. Reasons given for drainage include reduction in intraocular volume, which allows elevation of the buckle without the problems of increased intraocular pressure and settling of the breaks on the buckle allowing rapid closure of the breaks.

Complications during drainage include choroidal hemorrhage, retinal perforation, retinal incarceration, and choroidal neovascularization.

Arguments against drainage involve the avoidance of the complications of the drainage procedure. Studies by Chignell et al and Lincoff et al have shown that nondrainage procedures work as well as drainage procedures. ^{[28, 29]} In these patients, intraocular pressure must be monitored carefully. Most of these patients require a paracentesis or removal of liquid vitreous to elevate the buckle without choking off the central retinal artery. In addition, the subretinal fluid may take longer to reabsorb.

Complications

Postoperative glaucoma: Angle closure may occur secondary to a detachment and an anterior displacement of the ciliary body. Medical therapy is instituted as required. If this does not work, laser iridotomy followed by laser iridoplasty may be tried to open the angle.

Anterior segment ischemia: Patients at risk are those with sickle cell (SC) hemoglobinopathy and high encircling buckles. Mild cases may respond to topical or systemic steroids, but the encircling band needs to be cut in other cases.

Infection and extrusion of the buckle probably occur in 1% of cases. In these cases, the buckle needs to be removed.

Choroidal detachments have been reported to occur in as many as 40% of cases. They arise from vortex vein obstruction. Most cases can be followed without drainage.

Cystoid macular edema arises from the inflammatory response to the surgical trauma. Its incidence is reported to be around 25% of cases. Its treatment is based on the anti-inflammatory action of corticosteroids and nonsteroidal anti-inflammatory agents.

Strabismus following scleral buckling occurs in as many as 50% of cases. It is more common after reoperations. Most cases resolve spontaneously. However, as many as 25% have long-standing diplopia. The main cause is restrictive strabismus. This may be corrected with prisms, botulinum toxin injections, or surgery with adjustable sutures.

Macular pucker has been reported in as many as 17% of cases. A 2015 case series reported that peeling of the epiretinal membrane was associated with an improvement in visual acuity and OCT macular thickness. ^[30]

PVR is the most common cause of surgical failure. In this condition, membranes form on the surface of the retina and in the vitreous cavity. The membranes are composed of cells derived from the RPE, glia, and fibrocytes. The membranes contract and lead to tractional retinal detachment. Risk factors include the number and size of the retinal breaks, the number of previous operations, and the degree of breakdown of the blood-ocular barrier.

Persistent subclinical subfoveal fluid has been reported in up to 45% of eyes after successful retinal reattachment with scleral buckling at 6 months and 11% at 12 months. ^[31] An intravitreal injection of 0.3 mL of SF6 can displace the fluid out of the subfoveal space into the subretinal periphery allowing a quicker visual rehabilitation. ^[32]

Vitrectomy

Initially, PPV was reserved for complicated retinal detachments, such as giant retinal tears, PVR, and diabetic tractional detachments. Currently, many surgeons use it to treat primary uncomplicated retinal detachments.

Most surgeons use a 3-port approach with 23-gauge or 25-gauge instrumentation. If axial opacities (eg, lens fragments, vitreous hemorrhage) are present, they are removed.

A central core vitrectomy and removal of the vitreous from the margins of the breaks is the next step.

In a phakic eye, PPV causes a higher incidence of cataract formation than scleral buckling, thus care must be exercised in these maneuvers to prevent accidental damage to the lens. Because of the difficulties in completely relieving vitreoretinal traction without injuring the lens in phakic eyes, some have proposed that vitrectomy is the ideal procedure only in pseudophakic and aphakic eyes with RRD.

Drainage of subretinal fluid through a break or through a posterior drainage retinotomy is performed during fluid-air exchange.

Treatment of retinal breaks may be completed with cryotherapy prior to vitrectomy or with laser after the retina is attached. However, post-reattachment laser retinopexy is probably safer and performed more widely than cryotherapy before reattachment.

On occasion, retinal breaks remain unidentified and thus doom the results of the surgical procedure. Jackson and colleagues have described a technique for identifying these breaks. ^[33] This technique involves injection of trypan blue into the subretinal space with subsequent perfluorocarbon liquid-assisted extrusion of the dye through the occult breaks.

Intraocular tamponade with either long-acting gas or silicone oil is chosen according to the surgeon's preference. The advantages of gas are that it has a higher surface tension than silicone oil and it disappears on its own. The disadvantage is that it expands with changing atmospheric pressure. Patients with an intraocular gas bubble should not fly. On the other hand, silicone oil allows patients to fly but needs to be removed in a second procedure because of its inherent toxicity.

The ideal candidates for intraocular tamponade appear to be those with pseudophakia or aphakia or phakic eyes with posterior breaks.

Older series by Escoffery et al, Gartry et al, Hakin et al, and Oshima et al report a slightly lower primary reattachment rate with PPV than scleral buckling alone. ^{[34, 35, 36, 37]} However, a meta-analysis showed that vitrectomy provided more favorable visual outcomes and a higher reattachment rate than scleral buckling in pseudophakic eyes with primary rhegmatogenous retinal detachment. ^[38]

A retrospective multicentric interventional study reviewed 181 consecutive cases of noncomplex rhegmatogenous retinal detachment who underwent pars plana vitrectomy alone versus pars plana vitrectomy with the addition of a scleral buckle (encircling band). No statistically significant differences were found in the single-surgery success rate, final reattachment rate (after several surgeries), or final visual acuity between the 2 groups. ^[39]

Transconjunctival small-gauge vitrectomy has gained popularity. 25-gauge transconjunctival vitrectomy was introduced in 2002. ^[40] Several potential advantages over traditional 20-gauge vitrectomy have been described. These include improved patient comfort, faster wound healing, decreased inflammation, less conjunctival scarring, and a decreased surgical time in opening and closing. ^[41] In the beginning, there were certain shortcomings with 25-gauge vitrectomy. These included excessive flexibility of the instruments, poorer illumination, decreased fluidics, and an increase in wound leakage.

The 23-gauge vitrectomy was developed in response to some of these shortcomings. ^[42] In general, 23-gauge instruments exhibit more rigidity than 25-gauge instruments, which allows performing more peripheral maneuvers. Initially, both 25- and 23-gauge vitrectomy were mostly used in cases with macular epiretinal membranes. However, as surgeons became more familiar and acquainted with both systems, more complex cases were being operated on with transconjunctival small-gauge vitrectomy.

After a review of earlier reports, Heimann concluded that transconjunctival 25- and 23-gauge vitrectomy does not show any advantage over scleral buckling techniques in phakic eyes or 20-gauge vitrectomy in pseudophakic eyes. Furthermore, he claimed that transconjunctival 25- and 23-gauge vitrectomy worsens the outcome and increases the postoperative complication rate. ^[43]

More recent series suggest otherwise. A prospective case series published in 2008 reported that in 24 eyes with rhegmatogenous retinal detachment, 23-gauge transconjunctival vitrectomy provided a 91% anatomic success rate. This case series included eyes with complicated retinal detachments with multiple retinal breaks, inferior retinal detachments, giant breaks, concomitant choroidal detachment, vitreous hemorrhage, and secondary macular holes. Thus, their results compare favorably with those reported in the literature for 20-gauge vitrectomy. ^[44]

In another retrospective case series of 42 eyes with retinal detachment, a 93% one operation anatomic success rate was achieved with transconjunctival 25-gauge vitrectomy. ^[45] A retrospective study compared the outcomes between eyes operated with 20-gauge and 25-gauge vitrectomy. The authors found no significant differences between 25-gauge and 20-gauge vitrectomy in the repair of primary rhegmatogenous retinal detachment. ^[46]

Improvements in instrumentation and surgical techniques have made small-gauge transconjunctival vitrectomy the preferred vitrectomy technique for many vitreoretinal surgeons even in complex vitreoretinal cases.

Pneumatic retinopexy

Pneumatic retinopexy is an office procedure in which an expanding gas bubble is injected intravitreally through the conjunctiva together with laser retinopexy or cryopexy around the retinal break(s). The patient is positioned postoperatively to take advantage of the surface tension of the bubble to flatten the retina against the RPE.

Good candidates for pneumatic retinopexy are those with single retinal breaks or a group of breaks that do not exceed 1 clock hour and breaks that are confined to the superior two thirds of the fundus. Eyes with PVR grade B or greater usually are excluded. Teenagers can also be treated with this technique, and the overall success rate is similar to that of adults. The success rate is lower in patients with vitreous hemorrhage and detachments greater than 4.5 clock hours. A single procedure with successful reattachment results in better final visual acuity. ^[47]

Since the gas bubble expands with changing atmospheric pressure, patients should be warned of the perils of flying.

Pneumatic retinopexy can be considered a possible primary alternative to scleral buckling; however, the rates of missed or new retinal breaks are higher in pneumatic retinopexy.

Series by Hilton et al, McAllister et al, and Tornambe et al have reported an anatomic success rate of 80% with a single procedure. ^{[48, 49, 50, 51]} When additional surgery is performed, 98% have an anatomic success rate. In eyes with the macula detached for less than 2 weeks, the postoperative visual acuity is better than in those treated with conventional scleral buckling. Failure of a pneumatic procedure does not portend a poor visual prognosis. Eyes that fared badly were those that required multiple procedures to re-attach the retina or those that suffered complications. ^[52]

Reported complications include subretinal gas, delayed subretinal fluid reabsorption, endophthalmitis, extension of retinal detachment, macular hole formation, PVR, and new retinal breaks.

Lincoff episcleral balloon (Of historical interest only, since they are no longer on the market.)

Good candidates are eyes with single retinal breaks or a group of breaks in a single area. The balloon consists of a catheter with a balloon tip that is expanded with saline injection. Once the balloon is inflated, a scleral buckling effect is produced.

A conjunctival incision is made, and the deflated balloon is introduced into the Tenon space. Then, the balloon is inflated with saline. The balloon is deflated and removed after several days.

The anatomic success rate is about 85% in several series reported by Lincoff et al. ^[53] Visual results are comparable to those after successful scleral buckling.

Complications are rare, and the most important one is a shift in the location of the balloon. Corneal abrasions can be bothersome to the patient.

Comparing SB vs PPV vs PR

The key to a successful retinal repair is the identification of all breaks and their appropriate treatment. Modern PPV techniques with wide-angle illumination allow excellent visualization of the retina. In contrast, conventional SB relies on visualization via indirect ophthalmoscopy where the view may be hampered by poor pupillary dilation and media opacities. ^[19]  

A meta-analysis comparing primary vitrectomy versus scleral buckling for the treatment of RRD showed that scleral buckling was superior to vitrectomy in phakic eyes with uncomplicated RRD. In contrast, pars plana vitrectomy was superior in pseudophakic and aphakic eyes with RRD. ^[54]

In contrast, another meta-analysis reported that there were no significant differences in the proportions of primary reattachments of phakic eyes. Postoperative visual acuities were better in the scleral buckling group, probably owing to cataract formation in the vitrectomized eyes. In aphakic and pseudophakic eyes, the proportions of primary reattachment and postoperative visual acuity did not differ significantly between scleral buckling and pars plana vitrectomy. ^[55]

Patients with a RRD should be referred to a vitreoretinal specialist immediately.

Patients with a rhegmatogenous retinal detachment (RRD) should rest as much as possible prior to surgery. Following surgery, depending on whether an intraocular gas bubble is present, the patient will be instructed to maintain a certain head position.