Primary Surgical Approaches
The basic tenets governing successful reattachment following RRD include: (1) finding the break, typically with indirect ophthalmoscopy or wide-angle operative microscopy; (2) closing the break, through relief of vitreoretinal traction and apposition of retina to retinal pigment epithelium (RPE); and (3) permanently sealing the break via formation of a chorioretinal scar to prevent reaccumulation of subretinal fluid Both intraocular tamponade with gas or silicone oil and scleral indentation via SB facilitate acute closure of retinal breaks, whereas chorioretinal scar formation creates a long-lasting seal that takes several days to reach full strength. The modern surgical approaches to RRD repair—PR, SB, and PPV—utilize somewhat different methods to achieve these endpoints.
As noted above, SB is the oldest of the modern surgical approaches and its introduction predates contemporary vitreoretinal instrumentation, making it by definition an extraocular procedure. Though referred to by a single name, SB constitutes a heterogeneous collection of techniques applied to achieve a single goal: indentation of the sclera. This can be accomplished through the use of a wide variety of buckling elements (encircling, segmental, or a combination) that may be placed as either an explant, or less commonly, as a scleral implant. The encircling SB technique, devised by Schepens, predominated in the period immediately following its introduction due in large part to the lower rate of associated complications in comparison to the segmental technique of Custodis. However, in the mid-1960s, Lincoff and Kreissig improved segmental techniques through the application of less-toxic silicone sponges and these methods remain a viable, albeit uncommonly employed, alternative in modern RRD repair.17,18 Regardless of the specific technique employed, the goal of scleral indentation is closure of the retinal break through indirect relief of vitreoretinal traction (by shrinking the circumference of the globe) and retina to RPE apposition. The closed break is sealed permanently by chorioretinal scar creation via cryotherapy, laser photocoagulation, or, historically, diathermy. External drainage of subretinal fluid and temporary gas tamponade are optional adjuncts. In contrast to SB, PPV is an intraocular procedure, which relies on vitreoretinal instrumentation to remove the vitreous, drain subretinal fluid, and deliver intraocular gas. Break closure is achieved through direct relief of dynamic vitreoretinal traction via vitreous removal and effecting retina to RPE apposition via intraocular tamponade. Vitrectomy allows for permanent sealing of the break with intraocular laser application, though indirect laser and external cryotherapy are also commonly employed during vitrectomy procedures.
PR was introduced as means of repairing a subset of noncomplex RRDs— specifically those associated with a single break or small cluster of breaks in the superior retina—in an office-based procedure. This approach avoids the cost, time, and potential morbidity associated with SB or PPV performed in a formal operating suite. Unlike both SB and PPV, however, PR does not provide relief of vitreoretinal traction. Instead, breaks are closed temporarily with intraocular gas tamponade and sealed permanently by laser- or cryotherapy-induced chorioretinal scarring.
