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Chapter 103 – Scleral Buckling Surgery

Chapter 103 – Scleral Buckling Surgery

 

GEORGE A. WILLIAMS

 

 

 

 

 

DEFINITION

• Repair of rhegmatogenous retinal detachment via closure of retinal breaks by scleral indentation.

 

KEY FEATURES

• Identification, localization, and treatment of retinal breaks.

• Scleral imbrication.

 

 

 

INTRODUCTION

The primary surgical procedure for the repair of rhegmatogenous retinal detachment is scleral buckling, which can be accomplished using a variety of techniques and materials. The goal of scleral buckling is to close retinal breaks by indenting the eye wall and thus prevent the passage of liquefied vitreous into the subretinal space. A flexible approach that incorporates the benefits and advantages of different techniques can maximize the rate of anatomical and visual success while minimizing potential complications.

HISTORICAL REVIEW

Recognition of the importance of vitreoretinal traction and retinal breaks in the pathogenesis of retinal detachment by Gonin in 1919 ushered in a new era of repair in which both drainage of subretinal fluid and treatment of retinal breaks were employed. It was not until 1949 that Custodis introduced the concept of scleral buckling—the closure of retinal breaks by scleral indentation. The introduction of the binocular indirect ophthalmoscope by Schepens in 1951, along with the technique of scleral depression, revolutionized the localization of peripheral retinal pathology. Schepens further advanced scleral buckling techniques by combining scleral dissection, diathermy, and intrascleral implantation of silicone buckles. Lincoff and coworkers refined Custodis’s procedure by using silicone sponge explants and cryotherapy.[1]

PREOPERATIVE EVALUATION AND DIAGNOSTIC APPROACH

The diagnosis of rhegmatogenous retinal detachment is suggested by complaints of floaters, photopsia, peripheral visual field loss, and decreased visual acuity. In patients who have clear media, the diagnosis is confirmed by indirect ophthalmoscopy with scleral depression. Slit-lamp biomicroscopy with a three-mirror contact lens often is helpful. Identification and precise localization of all retinal pathology are prerequisites of successful scleral buckling surgery. The location and type of retinal breaks, as well as the size and duration of retinal detachment, are factors that help determine the timing and type of scleral buckling to be performed.

In patients who have opaque media, the retinal status may not be determinable with ophthalmoscopy. Diagnostic ultrasonography is critical in establishing retinal detachment. Bright-flash electroretinography can also be used. An extinguished electroretinogram in conjunction with compatible ultrasonographic findings is strongly indicative of extensive retinal detachment.

DIFFERENTIAL DIAGNOSIS

Not all retinal detachments are rhegmatogenous. Other causes need to be ruled out before retinal detachment repair is performed. Other causes include traction retinal detachments without retinal tears, Harada’s disease, eclampsia of pregnancy, tumors (e.g., choroidal hemangiomas and melanomas), and uveal effusion.

ALTERNATIVES TO SCLERAL BUCKLING

Rhegmatogenous retinal detachment can be repaired by surgical techniques other than scleral buckling. Pneumatic retinopexy involves injection of an expansible gas bubble into the vitreous cavity and postoperative positioning so that the gas bubble closes the retinal break.[2] The retinal break is treated with either cryopexy or laser photocoagulation. Usually, pneumatic retinopexy is reserved for mobile retinal detachments in the superior 8 clock hours of the retina that have no retinal break or group of breaks larger than 1 clock hour. The indications for scleral buckling versus pneumatic retinopexy remain controversial among vitreoretinal surgeons.

Vitrectomy techniques also can be used to repair rhegmatogenous retinal detachment. Vitrectomy surgery is described in Chapter 104 .

Alternatives to surgery include observation, which is usually reserved for chronic, inferior retinal detachments that are asymptomatic. Acute, symptomatic retinal detachments rarely achieve this status, so unless the patient is severely ill or refuses surgery, observation typically is not recommended in the acute setting.

Barrier laser photocoagulation to surround the detached area of retina can be used in both the acute and chronic settings. Unlike scleral buckling, pneumatic retinopexy, or vitrectomy, it is not curative. The goal is to “wall off” the detachment to preserve macular function. In acute, symptomatic retinal detachment, barrier laser photocoagulation may delay progression but is rarely successful in the long term.

ANESTHESIA

Scleral buckling can be performed with the patient under either local or general anesthesia. The anesthetic technique used is a matter of surgeon preference, but increasingly, local anesthesia is chosen. The advantages of local anesthesia include shorter operating time, quicker postoperative recovery, and possibly decreased morbidity and mortality in select cases. However, retrobulbar placement of local anesthetic is not without risk to the eye or the patient’s general health. Perforation of the globe, particularly in myopic patients, and damage to the optic nerve may result in permanent visual loss. Respiratory arrest and grand mal seizures also

 

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have been reported. These complications can be minimized by use of either a subconjunctival or a peribulbar technique.[3] [4] Subconjunctival or peribulbar infiltration with lidocaine (lignocaine) allows a limbal peritomy and dissection of Tenon’s capsule. Additional lidocaine and bupivacaine can then be administered by way of retrobulbar irrigation via a blunt cannula.

GENERAL TECHNIQUES

Conjunctival opening can be performed either at the limbus or several millimeters posterior to it. The conjunctiva is manipulated considerably during scleral buckling, so radial relaxation incisions are suggested to prevent tearing. In patients who have filtering blebs or recent limbal wounds, the peritomy can be extended posteriorly to avoid the area of concern. If only one or two quadrants are to be buckled, a 360° peritomy is not necessary. Conjunctiva and Tenon’s capsule can be reflected in the required quadrants only, and the appropriate muscles isolated.

After the peritomy, the space between Tenon’s capsule and sclera is entered. The muscle insertion is then engaged with a muscle hook, and the connections to Tenon’s capsule are identified and separated from the muscle. A traction suture is placed around the muscle. After all recti have been isolated, the surface of the sclera is inspected for evidence of thinning (most common superotemporally), staphyloma, and anomalous vortex veins. The locations of any abnormalities are noted before scleral depression is started or retinal breaks are marked.

No aspect of scleral buckling is more critical than accurate placement of the buckle on the sclera. This requires precise localization of retinal breaks on the scleral surface. Several instruments with which to localize and mark the sclera are available. For small flap tears or atrophic holes, a single mark on the posterior edge of the break is sufficient. Larger flap tears and nonradial tears require localization of both the anterior and posterior extent of the break ( Fig. 103-1 ).

 

 

Figure 103-1 Scleral marking technique for smaller and larger flap retinal tears.

Treatment of Retinal Breaks

The rationale for the treatment of breaks of the retina is to create an adhesion between the retinal pigment epithelium and the retina, and so prevent liquefied vitreous from entering the subretinal space. This is accomplished by inducing a thermal injury using one of three energy sources: diathermy, cryotherapy, or laser. The morphological and cellular response of the retina and retinal pigment epithelium to each of these energy sources is essentially similar. After 2 weeks, all three modalities show comparable effects on the retinal adhesive force.[5]

SPECIFIC TECHNIQUES

Explant Techniques

Explant techniques allow the surgeon to place scleral buckling material to support retinal pathology.[6] The ability to effectively treat retinal pathology without the need for scleral dissection has resulted in explant surgery becoming the procedure of choice for most retinal surgeons. Explants are made of either solid silicone rubber or silicone sponges and come in a variety of sizes and shapes.

Explants are secured to the sclera with partial-thickness scleral sutures. For most detachments, the actual element selected is not as important as the accurate localization and proper placement of the element with respect to the retinal break(s). Proper placement of the element requires an effective suturing technique that involves the use of a spatula needle with a 5–0 nonabsorbable suture such as polyester, nylon, or polypropylene. Sutures are placed a minimum of 2?mm farther apart than the width of scleral contact for a given element (e.g., 9?mm apart for a 7?mm element). To ensure that the most posterior edge of the retinal break is supported, the posterior suture is placed a minimum of 2–3?mm posterior to the scleral localization mark ( Figs. 103-2 and 103-3 ).

The placement of explant material can be either segmental or encircling. Segmental buckles usually are reserved for detachments with single or closely spaced retinal breaks less than 1 clock hour in total extent. Although segmental buckles close isolated tears effectively, they are less useful in preventing new breaks, since they provide little retinal support elsewhere. Encircling procedures are particularly indicated in patients who have the following:

 

 

Figure 103-2 Suture placement for both tire and meridional elements.

• Multiple breaks in different quadrants,

• Aphakia,

 

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• Pseudophakia,

• Myopia,

• Diffuse vitreoretinal pathology, such as extensive lattice degeneration or vitreoretinal degeneration, and

• Proliferative vitreoretinopathy.

 

 

Figure 103-3 Placement of sutures for radial sponge.

 

 

Figure 103-4 Correct position of buckle for flap retinal tear.

The anteroposterior position of the encircling element depends on the location of the vitreoretinal pathology to be supported. When retinal breaks in the detached retina are associated with traction, the buckle should be positioned such that the posterior edge of the break lies on the posterior crest of the buckle ( Fig. 103-4 ). The buckling effect should extend for 30° on either side of the tear and extend anteriorly to the ora serrata. If the encircling element is to support pathological conditions in an attached retina, such as a retinal break, it should be

 

 

Figure 103-5 Technique for scleral dissection.

positioned to reinforce the most posterior aspect of the condition. If no specific pathological factor is to be supported, the encircling element should buttress the posterior margin of the vitreous base.

The buckle height of encircling elements can be obtained in two ways. For thin encircling elements, such as solid silicone bands, the explant can be shortened in relation to the circumference of the globe. The second method to obtain buckle height is via suture placement. This technique is used with wider and thicker explants and does not require the element to be shortened in relation to the ocular circumference. The farther apart the bites of the mattress suture are placed, the greater the height of the buckle when the sutures are tightened.[6]

Implant Techniques

The current system of scleral buckling using implant techniques for rhegmatogenous retinal detachment was begun in 1960 by Schepens and associates with their description of scleral dissection, intrascleral placement of silicone buckles (implants), and diathermy. Subsequently, modifications and refinements of the technique have been described ( Figs. 103-5 and 103-6 ). [1] [7]

 

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Figure 103-6 Scleral dissection. Placement of implant in scleral dissection and closure of scleral flaps.

Drainage of Subretinal Fluid

Indications for drainage of subretinal fluid during scleral buckling remain controversial. Some authors believe that most cases can be managed without drainage of subretinal fluid, whereas others believe that drainage is a crucial aspect of the procedure.[6] [8] The rationale for drainage of subretinal fluid is twofold:

• To diminish intraocular volume so as to allow elevation of the buckle without elevating intraocular pressure (IOP),

• To allow the retina to settle on the elevated buckle by removing fluid from the subretinal space.

Effective drainage of subretinal fluid places the retinal breaks in juxtaposition to the buckle, thereby facilitating closure of the breaks.

The selection of an external drainage site is affected by several factors. Clearly, the location of subretinal fluid is a primary concern. It is not necessary to drain where the amount of fluid is greatest, but rather where there is adequate fluid to safely enter the subretinal space. Whenever possible, it is preferable to drain just above or below the horizontal meridian, either temporally or nasally ( Fig. 103-7 ). This location avoids the major choroidal vessels and vortex veins.

Again, whenever possible, it is preferable to drain in the posterior third of the bed of the buckle. This provides adequate support of the drainage site in the event of a complication such as retinal incarceration or choroidal hemorrhage, and it also provides immediate closure of the drainage site when the buckle is tightened. If, because of the configuration of the detachment or the position of the buckle, it is not possible to drain in the bed of the buckle, closure of the drain site with a mattress suture should be considered. Drainage outside the bed of the buckle allows the buckle to be pulled up as drainage proceeds. Entry through the choroid and into the subretinal space is performed with a needle (27–30 gauge). Usually, the presence of fluid around the needle signifies entry into the subretinal space. As the fluid drains, it is important to maintain a relatively normal and constant IOP to prevent retinal incarceration and choroidal hemorrhage.

After successful subretinal fluid drainage and closure of the drainage site, the buckle is positioned with the appropriate preplaced

 

 

Figure 103-7 Location of preferred drainage sites.

scleral sutures to support the retinal pathology. Any suture that overlies a retinal break is tightened first, followed by the remainder of the sutures. The encircling band, if present, is then adjusted with a silicone sleeve. As the sutures are tightened, they are secured with temporary ties, and the optic nerve is inspected to confirm arterial perfusion. Once the buckle is positioned and the band adjusted, the fundus is inspected again to determine the status of the retinal breaks and the perfusion of the optic nerve. The temporary ties allow easy adjustment of the buckle height or position if necessary.

Nondrainage procedures can be used to reattach the retina, with success rates comparable to those of drainage procedures. The primary advantage of a nondrainage procedure is that it avoids the potential complications associated with transchoroidal drainage. In eyes with relatively shallow detachments, the eye may soften enough after scleral depression and cryopexy to allow placement of the buckle without IOP problems. Waiting several minutes between tightening of the scleral sutures also may soften the eye. However, nondrainage techniques often require the IOP to be lowered by additional medical or surgical means.

Closing

After final adjustment of the buckle, the sutures are tied and the knots rotated to the posterior edge of the buckle. Tenon’s capsule and the globe can then be irrigated with an antibiotic solution. Retrobulbar irrigation with 0.50% bupivacaine significantly decreases postoperative pain after both general and local anesthesia.

Tenon’s capsule is then identified in all quadrants. A layered closure, initially closing Tenon’s capsule to the muscle insertions in all quadrants, has advantages ( Fig. 103-8 ). This ensures that the explant and the nonabsorbable sutures are covered by the thick Tenon’s capsule and also removes tension on the conjunctival closure, which minimizes the possibility of buckle erosion. During conjunctival closure, the relaxation incisions are closed with a running 6–0 plain gut suture. The conjunctiva is secured at the limbus with one or more sutures.

 

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Figure 103-8 Closure of Tenon’s capsule to all rectus muscles.

COMPLICATIONS

Intraoperative Complications

SCLERAL PERFORATION.

Scleral perforation during placement of scleral sutures is a potentially disastrous complication. Perforation usually is noticed at the time of suture placement and is heralded by the presentation of blood, pigment, or subretinal fluid through the suture tract.

DRAINAGE COMPLICATIONS.

The most common drainage complications are retinal incarceration and choroidal or subretinal hemorrhage.[9] Retinal incarceration may occur despite attempts to avoid large fluctuations in IOP during drainage. It is identified by the characteristic dimpled appearance of the retina over the drainage site. Minimal degrees of incarceration rarely result in retinal breaks, but large amounts of incarceration require support with a buckle.

Choroidal (or subretinal) hemorrhage is perhaps the most feared complication of subretinal fluid drainage; it usually occurs at the time of choroidal perforation and is marked by the appearance of blood at the drainage site. If this occurs, the drainage site should be closed as quickly as possible with either the buckle or a sclerotomy suture and the IOP elevated above the systolic perfusion pressure. If the drainage site is temporal, the eye should be positioned to place the located site as inferiorly as possible to prevent gravitation of the subretinal blood to the fovea.

Postoperative Complications

GLAUCOMA.

A variety of secondary glaucomas may develop after scleral buckling. Angle closure after scleral buckling may take place with or without pupillary block. When pupillary block is present, accompanying iris bombé occurs; usually, however, pupillary block does not occur. One presumed mechanism of the angle closure in these cases is shallow detachment of the ciliary body, which results in anterior displacement of the ciliary body and occlusion of the angle. Anterior segment ischemia also may cause glaucoma.

INFECTION AND EXTRUSION.

Scleral buckling materials constitute foreign bodies and therefore carry the risk of infection and are at risk for extrusion. The incidence of explant infection and extrusion is about 1%. Effective management of infected scleral buckling material usually requires removal of any soft silicone sponge or large solid silicone elements. Topical and systemic antibiotics occasionally result in symptomatic improvement, but they are rarely curative. Removal of the scleral buckling material carries a redetachment risk of 4–33%.[10]

CHOROIDAL DETACHMENT (CHOROIDAL EDEMA).

Accumulation of serous or serosanguineous fluid in the suprachoroidal space is relatively common after scleral buckling and is referred to as choroidal detachment or choroidal edema, even though it is truly a choroidal (or ciliary body) effusion. Choroidal detachment occurs after both implant diathermy procedures and explant cryotherapy procedures. The overall incidence of choroidal detachment is about 40%.[11]

CYSTOID MACULAR EDEMA.

Using cryotherapy and explant techniques, the incidence of angiographic cystoid macular edema 4–6 weeks after surgery in phakic eyes is 25–28%. [12]

MACULAR PUCKER.

Macular pucker is a major cause of decreased vision after scleral buckling. The incidence of macular pucker formation is in the range of 3–17%. Risk factors identified include preoperative proliferative vitreoretinopathy of grade B or greater, age, total retinal detachment, and vitreous loss during drainage.[13]

DIPLOPIA.

The incidence of postoperative diplopia is low. In a series of 750 patients whose retinas were reattached with scleral buckling, 3.3% complained of diplopia postoperatively.[14] The incidence of diplopia is greater after reoperations.

CHANGES IN REFRACTIVE ERROR.

The extent and direction of change in refractive error after scleral buckling depend on the surgical technique employed. Segmental buckles, whether implants or explants, have little effect on refractive error. However, large radial elements, such as full-thickness sponges that extend anteriorly beyond the ora serrata, may induce an irregular astigmatism. Encircling procedures induce the greatest change in refractive error. This change is greater for phakic than for aphakic eyes because of anterior displacement of the lens, which results in an increased myopic shift. [15]

 

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OUTCOME

The anatomical results following scleral buckling for rhegmatogenous retinal detachments are impressive. An overall reattachment rate of at least 90% is achievable. Unfortunately, the visual results after scleral buckling do not parallel the anatomical results. Multiple factors correlate with visual and anatomical prognosis after scleral buckling. Detachments with the macula attached (macula-on) at the time of surgery have a significantly better anatomical and visual prognosis than do detachments in which the macula has become detached preoperatively. Cumulative data from three series demonstrate successful anatomical reattachment in 99% of cases of macula-on retinal detachment. [16] [17] [18] However, despite this high anatomical success rate, decreased visual acuity can occur. Usually this is caused by postoperative macular changes, such as cystoid macular edema or macular pucker. Approximately 10% of patients who have macula-on detachments suffer a visual loss of two Snellen lines or greater with respect to their preoperative vision.

Detachment of the macula results in a variable degree of permanent photoreceptor damage that correlates with the duration of the macular detachment. [6] Macula-off detachments are usually larger and of greater duration than are macula-on detachments. Therefore it is not surprising that retinal detachments that involve the macula have a lower rate of anatomical and visual success than do retinal detachments with macular involvement. The overall anatomical success rate for macula-off detachments is at least 90%, but despite this high rate of reattachment, only 40–60% of patients have a final visual acuity of 20/50 or better. [19] [20] [21] [22] [23]

 

 

REFERENCES

 

1. Wilkinson CP, Rice TA, eds. History of retinal detachment surgery. In: Michels RG. Retinal detachment, ed 2. St Louis: Mosby; 1997:251–334.

 

2. Hilton GF, Grizzard WS. Pneumatic retinopexy. A two-step outpatient operation without conjunctival incision. Ophthalmology. 1986;93:626–41.

 

3. Mein CE, Woodcock MG. Local anesthesia for vitreoretinal surgery. Retina. 1990;10:47–9.

 

4. Orgel IK, Williams GA. Peribulbar anesthesia for scleral buckling surgery. Vitreoretinal Surg Technol. 1992;1:4–5.

 

5. Kita M, Negi A, Kawano S, Honda Y. Photothermal cryogenic and diathermic effects on retinal adhesive force in vivo. Retina. 1991;11:441–4.

 

6. Williams GA, Aaberg TM Sr. Techniques of scleral buckling. In: Ryan SJ, ed. Retina, vol 3. St Louis: Mosby; 2001:2010–46.

 

7. Schepens CL. Retinal detachment and allied disease. Philadelphia: WB Saunders; 1983.

 

8. Sasoh M. The frequency of subretinal fluid drainage and the reattachment rate in retinal detachment surgery. Retina. 1992;12:113–7.

 

9. Burton RL, Cairns JD, Campbell WG, et al. Needle drainage of subretinal fluid: a randomized clinical trial. Retina. 1993;13:13–6.

 

10. Wiznia RA. Removal of solid silicone rubber exoplants after retinal detachment surgery. Am J Ophthalmol. 1983;95:495–7.

 

11. Packer AJ, Maggiano JM, Aaberg TM, et al. Serous choroidal detachment after retinal detachment surgery. Arch Ophthalmol. 1983;101:1221–4.

 

12. Meredith TA, Reeser FH, Topping TM, Aaberg TM. Cystoid macular edema after retinal detachment surgery. Ophthalmology. 1980;87:1090–5.

 

13. Lobes LA, Burton TC. The incidence of macular pucker after retinal detachment surgery. Am J Ophthalmol. 1978;85:72–7.

 

14. Smiddy WE, Loupe DN, Michels RG, et al. Extraocular muscle imbalance after scleral buckling surgery. Ophthalmology. 1989;96:1485–90.

 

15. Smiddy WE, Loupe DN, Michels RG, et al. Refractive changes after scleral buckling surgery. Arch Ophthalmol. 1989;107:1469–71.

 

16. Tani P, Robertson DM, Langworthy A. Rhegmatogenous retinal detachment without macular involvement treated with scleral buckling. Am J Ophthalmol. 1980;90:503–8.

 

17. Wilkinson CP. Visual results following scleral buckling for retinal detachments sparing the macula. Retina. 1981;1:113–6.

 

18. Girard P, Mimoun G, Karpouzas I, Moutefiove G. Clinical risk factors for proliferative vitreoretinopathy after retinal detachment surgery. Retina. 1994;14:417–24.

 

19. Tani P, Robertson DM, Langworthy A. Prognosis for central vision and anatomic reattachment in rhegmatogenous retinal detachment with macula detached. Am J Ophthalmol. 1981;92:611–20.

 

20. Burton TC. Preoperative factors influencing anatomic success rates following retinal detachment surgery. Trans Am Acad Ophthalmol Otolaryngol. 1977;83:499–505.

 

21. Burton TC, Lambert RW Jr. A predictive model for visual recovery following retinal detachment surgery. Ophthalmology. 1978;85:619–25.

 

22. Girard P, Karpouzas I. Visual recovery after scleral buckling surgery. Ophthalmologica. 1995;209:323–8.

 

23. Hussan TS, Sarrafizadeh R, Ruby A, et al. The effect of duration of macular detachment on results after the scleral buckle repair of primary macula-off retinal detachments. Ophthalmology. 2002;109:146–152.

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