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Article Date: 7/1/2014

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Vitrectomy Without Scleral Buckling for Rhegmatogenous Retinal Detachment

Vitrectomy Without Scleral Buckling for Rhegmatogenous Retinal Detachment

Buckles are obsolete in the era of refractive surgery.

STEVE CHARLES, MD

Vitrectomy without scleral buckling for rhegmatogenous retinal detachment (RRD) is often referred to as “primary vitrectomy,” a term that at least initially implied that scleral buckling was the standard of care and should be attempted before resorting to vitrectomy.

This “rescue therapy” approach is considered conservative, and surgeons apply it in many specialties and disease processes. However, it can produce the unintended consequence of delaying adoption of improved therapies and putting the patient through an unnecessary procedure.

Anterior-segment surgeons do not try intracapsular cataract extraction before resorting to phacoemulsification or refractive keratoplasty (RK) before LASIK. Long bone fractures were not randomized to sham therapy after casts were developed.

No high-quality clinical trials have compared vitrectomy, scleral buckling, and combined vit-buckle procedures for RRD surgery because a large number of clinical variables exist, as well as many treatment options, which are often used in combination.

Preoperative variables include the type, size and number of breaks, lens status, refractive error, vitreous hemorrhage, vitreous traction, family history, status of the fellow eye, medical status, and many others. Variables in scleral buckling include: hard silicone vs sponges, subretinal fluid drainage vs nondrainage, radial vs circumferential elements, encircling vs segmental buckles, use of air or gas, paracentesis, and more.

Steve Charles, MD, FACS, FICS, is clinical professor of ophthalmology at the University of Tennessee College of Medicine in Memphis. Dr. Charles reports significant financial interest in Alcon. He can be reached via e-mail at scharles@att.net.

Variables in vitrectomy include: using air, SF6, C3F8, or silicone oil; laser vs cryo; 20-, 23-, or 25-gauge; use of liquid perfluorocarbons; combined lensectomy or phacoemulsification; and postoperative positioning.

Scleral buckle advocates have stated that pneumatic retinopexy often causes PVR, but they manage “fish-mouthing” in scleral buckling with gas injection. This is not rational. Some surgeons use vitrectomy only for pseudophakic eyes, believing, incorrectly, that vitrectomy causes de novo nuclear sclerosis, when, in fact, it only causes progression of pre-existing nuclear sclerosis.

COMPLICATIONS OF SCLERAL BUCKLING

Proponents of scleral buckling often minimize the complications of scleral buckling. They state that they “never” produce strabismus, yet a high-quality prospective trial reported by the late Ron Michels, an excellent surgeon, demonstrated a 50% incidence of increased tropias and phorias.

Encircling buckles may result in damage to the superior oblique or superior rectus tendons, producing problematic vertical strabismus. Fortunately, most buckle surgeons have abandoned the unnecessary practice of removing and reattaching the extraocular muscles.

Aggressive traction on retromuscle traction sutures, especially with small-diameter sutures, can damage and potentially sever intraocular muscle tendons. Aggressive stripping of the intramuscular septum, Tenon’s capsule, and episclera, combined with cautery, can create adhesions between these layers, causing problems for subsequent glaucoma filtering procedures.

Many surgeons use encircling bands in essentially all buckle cases. A circumferential buckle produces the same outcomes in most instances without inducing myopia or causing damage to the extraocular muscles, potentially causing diplopia or damage to the levator aponeurosis and resulting in ptosis.

Patients spend substantial sums of money in the pursuit of emmetropia; LASIK, photorefractive keratectomy (PRK), and refractive lens exchange have raised patients’ expectations of life without glasses or contacts.

Cataract surgery patients expect emmetropia as well; substantial efforts have been applied in microincisional surgery, foldable IOLs, toric IOLs, multifocal IOLs, (minimally) accommodative IOLs, and femtosecond laser surgery. An encircling band produces 2.75 D of myopia on average, which is completely unacceptable to a patient who has paid for refractive cataract surgery, LASIK, or PRK.

More serious complications of scleral buckling include late intrusion of the buckle and buckle extrusion and infection. Intraoperative complications include a 5% incidence of retinal incarceration at the drainage site when using cut-down drainage, as well as bleeding related to the drainage site. Scleral, choroidal, or retinal perforation with scleral sutures is not uncommon, either — sometimes with serious consequences.

VIT-BUCKLES

Many vitreoretinal surgeons use encircling bands in conjunction with vitrectomy for repair of RRD — so-called vit-buckles. I have not used this approach for two decades to eliminate buckling-induced refractive errors, strabismus, ptosis, and pain, as well to reduce operating times and, as a result, labor costs.

Brazitikos showed that vitrectomy without scleral buckling for retinal detachment produced better outcomes than vit-buckles. Patients would not want a vitreoretinal surgeon to use encircling bands when they are undergoing vitrectomy repair of retinal detachment if they knew about the outcomes and complications. No level 1 evidence exists that vit-buckles produce better outcomes than vitrectomy without scleral buckles, even in cases of PVR.

VITRECTOMY TECHNIQUES

Wide-angle visualization techniques and/or scleral depression are essential if performing vitrectomy for retinal detachment repair. Contact-based wide-angle visualization (Volk, AVI) produces a 10º greater field of view than noncontact (BIOM, ReSight, Merlin), and it eliminates all corneal asphericity (keratoconus, limbal relaxing incisions, RK, penetrating keratoplasty, cataract surgery, LASIK, PRK).

In addition, contact-based wide-angle visualization greatly reduces the need for ocular rotation to view the periphery, which reduces flexural forces on 25-gauge tools.

As with scleral buckling, all retinal breaks must be identified and treated with retinopexy. Traction to the flap, as well as vitreous traction surrounding all breaks, must be eliminated to produce ~90% single procedure success rates.

Internal drainage of subretinal fluid, performed simultaneously with fluid-air exchange with a soft-tip cannula, usually drains most of the subretinal fluid. If internal drainage is initiated prior to fluid-air exchange, posterior migration of subretinal fluid is reduced (Figure 1, page 22).

Figure 1. If internal drainage is initiated prior to fluid-air exchange, posterior migration of subretinal fluid is reduced.

The surgeon can perform drainage retinotomy if substantial posterior migration of subretinal fluid occurs, or the retinal breaks are very small and far peripheral, making internal drainage challenging.

Another option for removal of subretinal fluid is perfluorocarbon liquids: N-perfluoro-octane (PFO) is the preferred agent because the interface is visible, unlike with perfluorodecalin. PFO will remove all subretinal fluid if the surgeon uses optimal techniques, while internal drainage of subretinal fluid plus fluid-air exchange always leaves a thin layer of fluid that must be pumped out by the retinal pigment epithelium.

Complete removal of subretinal fluid, enabled by PFO, may allow for the use of a shorter-acting gas or even air for surface tension management. Because PFO causes subretinal fluid to float anteriorly, the surgeon should be careful to remove all subretinal fluid anterior to the retinal breaks, to enable surrounding all of the breaks with endolaser. Extending the break to the ora or making a very peripheral, small drainage retinotomy can do this.

However, the best approach is to slowly drain subretinal fluid through the retinal break using a 25-gauge soft-tip cannula just when the PFO reaches the break. The surgeon should be careful not to remove any PFO. The MedOne (Sarasota, FL) 25-gauge dual-bore viscous fluid infusion cannula is ideal for injecting PFO while allowing infusion fluid egress to maintain appropriate IOP (Figure 2).

Figure 2. A viscous fluid infusion cannula can be ideal for injecting N-perfluoro-octane while allowing fluid egress to maintain an appropriate intraocular pressure.

25-GAUGE SUTURELESS VITRECTOMY

I use a 25-gauge sutureless approach for all vitrectomies, including for RRDs, PVR (Figure 3), giant breaks, and diabetic traction retinal detachments. Just as today’s patients expect emmetropia without strabismus or ptosis, they expect a painless procedure and a noninflamed eye.

Figure 3. A 25-gauge sutureless approach can be used for all vitrectomies, including for PVR, RRDs, giant breaks, and diabetic tractional without retinal detachments.

A noninflamed, pain-free eye is not achievable with 20-gauge sutured wounds or vit-buckles. Contrary to what some surgeons believe, 25-gauge vitrectomy fluidics are preferable to 23- or 20-gauge fluidics for RD cases because port-based flow limiting due to a smaller lumen reduces pulsatile vitreoretinal traction.

I strongly recommend the use of the highest possible cutting rate for all tasks and all cases — especially for giant breaks and other RD cases. I use only the Alcon Constellation Vision System currently with 5,000 cuts/minute, soon to be 7,500 cuts/minute. Sutured-on contact lenses damage the conjunctiva, cause subconjunctival bleeding, and are inappropriate for sutureless, transconjunctival surgery.

SUMMARY

Sutureless, transconjunctival, microincisional vitrectomy is ideal for RD repair. In my opinion, vit-buckles are no longer indicated; the focus should be on microincisional vitrectomy techniques and wide-angle visualization to repair RDs, without causing pain, refractive error, strabismus, ptosis, cosmetic problems, or longer, more costly operating times. RP



Retinal Physician, Volume: 11 , Issue: July 2014, page(s): 22, 24-26

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