With an annual incidence estimated at about 10 to 18 in 100,000 and a prevalence of approximately 0.7%, primary rhegmatogenous retinal detachment represents a treatable cause of otherwise profound, permanent visual loss.^1-5 Thus RRD repair represents a core competency of the retinal physician. 

Though advances in vitreoretinal surgery have altered trends in choice of repair techniques, the general principles of successful treatment of RRD have remained the same since the popularization of scleral buckling techniques by Charles Schepens and others in the early 1950s.

Specifically, the key principles to successful repair of RRD are identification of rhegmatogenous breaks, relief of traction on causative breaks and treatment of these breaks. These can be accomplished by use of scleral buckling and/or pars-plana vitrectomy. In selected cases, pneumatic retinopexy or demarcation (laser or cryotherapy) may also be considered.

• Scleral buckling. As the standard of care for decades, scleral buckling procedures (SBP) represent a well-understood and reliable method of RRD repair. Advantages offered by SBP include lower incidence of cataract, endophthalmitis, 360-degree support of the vitreous base or peripheral retina, and the ability to perform surgery as an extraocular procedure (except in cases requiring external drainage of subretinal fluid). Additionally, they can be performed in minimally equipped operative settings and for considerably less cost.

Disadvantages include frequent induction of postoperative myopia, difficulty in management of very large and/or posterior retinal breaks and the rare possibilities of buckle erosion or induced strabismus.

• Vitrectomy. The primary advantages of vitrectomy include the ability to remove intraocular media opacities and vitreous traction, improved visualization, ability to internally drain and visualize retinal reattachment and ease of laser/cryotherapy application regardless of location. Additionally, mechanical effects of buckling such as induced myopia and more rare complications such as erosion and strabismus are avoided.

A significant disadvantage of vitrectomy in phakic eyes is the development or progression of nuclear sclerotic cataracts. There have also been some suggested long-term associations between vitrectomized, pseudophakic eyes and open-angle glaucoma. There is also some evidence that failed vitrectomy surgery may be associated with more severe proliferative vitreoretinopathy. Additionally, the cost and equipment requirements of vitrectomy are considerably higher than those of pneumatic retinopexy and scleral buckling.

• Pneumatic retinopexy. The key to successful RRD repair with pneumatic retinopexy (PR) is appropriate patient selection. Generally, the ideal patient would have no media opacities to allow full visualization of the retina, single or few breaks located in the upper 6 to 8 eight clock hours of the eye, no larger than 1 clock hour in dimension, and separated by 2 clock hours or less along with a complete posterior vitreous detachment and lack of lattice degeneration.

For those patients felt to be appropriate candidates, the major advantages of this method include the ability to perform it as an office procedure with minimal anesthesia requirement, lower morbidity and post-procedure recovery and significantly lower cost.

Table 1. Choice of Retinal Detachment Repair Technique12,13  Procedure Relative Indications Relative Contradictions Scleral buckle Phakic patients with uncomplicated, single break RD Posterior breaks Media opacities/hemorrhage Scleral thinning/scleromalacia Vitrectomy Pseudophakia Posterior breaks Media opacities/hemorrhage PVR Uncomplicated, phakic RD Young, myopic patients Inferior retinal dialysis Vitrectomy + scleral buckle Severe PVR Inferior traction Incomplete removal of traction Uncomplicated, phakic RD Scleral thinning/scleromalacia Pneumatic retinopexy Localized small superior breaks Multiple separated breaks Inferior breaks Lack of PVD, inferior PVD Demarcation (laser or cryo) Small, shallow, subclinical RD Asymptomatic, signs of chronicity Sick patients unable to position or undergo surgery Rapidly progressive RD Extension posterior to equator Significant traction or PVR
Figure 2. Proliferative vitreoretinopathy following a scleral buckling procedure.		Figure 3. Proliferative vitreoretinopathy following a vitrectomy.
Table 2. Success Rates for Retinal Detachment Repair by Technique: Phakic Patients12,13  RETROSPECTIVE  SB PPV SB/PPV Total eyes Miki et al., 2001 100% 96% 225  Mansouri et al., 2010 (phakic subgroup) 86% 78% 84% 168 TRI recurrent RD study group, St. Louis, 2008 86% 78% 84% 286 PROSPECTIVE SB PPV SB/PPV Total eyes Heimann et al., 2007 (phakic subgroup) 63.6% 61.8%

The primary disadvantages of PR are its approximately 10 percent lower single operation success rate relative to scleral buckling,^6,7 and the small subset of RRD patients who would be appropriate candidates.

Of the repair techniques mentioned, the most broadly applicable are vitrectomy, scleral buckling or a combination of the two. Comparative studies have shown both to be effective, with a trend toward superiority for scleral bucking in phakic patients and toward vitrectomy in pseudphakic patients. Regarding pneumatic retinopexy, studies have indicated a single operation success rate of approximately 80 percent and greater than 95 percent with reoperations.^8-11

Despite comparable success rates, there has been a clear and well-known trend away from scleral buckling toward primary vitrectomy over the past decade. An analysis of the Medicare fee-for-service database, BESS (Part B Extract Summary System), by CPT code reveals that during the period from 2000 to 2010, scleral buckling fell by two-thirds, while vitrectomy doubled and utilization of other techniques remained stable.

It is likely that factors such as advances in small-gauge vitrectomy surgery, improved wide-angle viewing systems and reduced emphasis on scleral buckling during fellowship training have contributed to these trends.

• Proliferative vitreoretinopathy. Occurring in 5 to 10 percent of all RRDs and implicated in 75 percent of postoperative redetachments, proliferative vitreoretinopathy is the process involving formation of intravitreal, preretinal or subretinal membranes.^19,20 It results from abnormal cellular proliferation at the vitreoretinal interface of fibroblast-like cells, which have been shown to derive from several progenitors, particularly astrocytes and RPE cells.^20,21 Early signs include the appearance in the vitreous of pigmented cells and formation of highly cellular membranes. Late changes include an increase in extracellular Type I collagen, in contrast to the Type II collagen of normal vitreous.²²

Although rates of postoperative PVR following vitrectomy and SBP have been similar, an important distinction has been the observed phenomenon that when PVR occurs, it is often severe in cases of failed vitrectomy relative to failed SBP. This idea was also supported in a classic experiment in 1984 by Hung-Tao Hsu, MD, and colleagues, in which vitrectomized rabbit eyes developed more severe PVR than nonvitrectomized eyes after intraocular injection of tissue-cultured fibroblasts.²³ A recent study of 50 different biomarkers in subretinal fluid from eyes with RRD showed differentially elevated levels of interleukin-3, chemokine ligand-3 and macrophage inhibitory factor, among others.²⁴ Several other studies have implicated a role in overexpression of platelet-derived growth factor.^25,26 

Table 3. Success Rates for Retinal Detachment Repair by Technique: Pseudophakic Patients13-18 RETROSPECTIVE SB PPV SB/PPV Total eyes Mansouri et al., 2010 (pseudophakic group) 80% 86.5% 80.3% 118 TRI recurrent RD study group, St. Loius, 2008 80% 87% 80% 286 PROSPECTIVE SB PPV SB/PPV Total eyes Stangos et al., 2004 98% 92% 71 Sharma et al., 2005 76% 84% 50 Brazitikos et al., 2005 83% 94% 150 Weichel et al., 2006 93% 94% 152 Heimann et al., 2007 (pseudophakic group) 53% 72% 265   Table 4. Rates of PVR in Various Studies14-18,27,28 RETROSPECTIVE PVR Rates Total eyes SB PPV SB/PPV Tewari et al., 2003 5% 10% 44 Ahmadieh et al., 2005  29.4% 35.35% 225 Stangos et al., 2004 2.2% 7.7% 71 Sharma et al., 2005 20% 4% 50 Brazitikos et al., 2005 5.3% 4% 150 Weichel et al., 2006 5.3% (overall)   152 Heimann et al., 2007 (phakic subgroup) 12.4% 16.4% 416 Heimann et al., 2007 (pseudophakic subgroup) 22.6% 15.2% 265 PROSPECTIVE PVR Rate Total eyes SB PPV SB/PPV Tewari et al., 2003 5% 10% 44 Ahmedieh et al., 2005 29.4% 35.35% 225 Stangos et al., 2004 2.2% 7.7% 71 Sharma et al., 2005 20% 4% 50 Braitikos et al., 2005 5.3% 4% 150 Weichel et al., 2006 5.3% (overall) 152 Heimann et al., 2007 (phakic subgroup) 12.4% 16.4% 416 Heiman et al., 2007 22.6% 15.2% 265

Thus, there is some evidence that removal of vitreous, such as after vitrectomy, may allow more aggressive forms of PVR to develop in those cases when primary RRD repair fails. This may be due to the anti-proliferative cytokine and biologic milieu of the vitreous, or by the physical separation afforded by vitreous of a PVR-stimulating cytokine-rich environment from the effector.

• Other causes. Uncommonly, primary RRD repair may fail unrelated to PVR. In these cases, the failure may result from:

Addressing the underlying cause of the retinal redetachment is the standard treatment for failed RRD repair. If previously untreated breaks or new breaks are found to be the cause for redetachment, a return to the operating room is merited, either with repeat vitrectomy, or vitrectomy with scleral buckling.

PVR poses a more difficult challenge, and pharmacologic approaches (steroids, anti-neoplastic/anti-proliferative agents, growth factor pathway inhibitors) that have shown limited success in animal models have not translated into successful management in humans.^29-33

When redetachment occurs secondary to PVR, surgical intervention is required and the aims of surgery are to relieve induced tractional forces, to close all retinal breaks and to help maintain ciliary body function. Mild to moderate cases of PVR may be treated with vitrectomy and membrane peeling alone. More severe cases may require the additional support of a scleral buckle as well as membrane peeling, use of perfluorocarbon liquids, relaxing retinotomies and long-term tamponade with silicone oil.  REVIEW