Article Date: 3/1/2012

Vitrectomy Without Scleral Buckling for Retinal Detachment Management
SURGICAL PRECISION

Vitrectomy Without Scleral Buckling for Retinal Detachment Management

Scleral buckles may seem necessary, but they can do more harm than good.

Steve Charles, MD, FACS, FICS

Today’s refractive and cataract surgery patient expects emmetropia, virtually instantaneous visual rehabilitation and no double vision, sutures, discomfort or inflammation. Such outcomes cannot be achieved with vitrectomy by scleral buckling or combining a buckle. Traditionalists refer to vitrectomy without scleral buckling for rhegmatogenous retinal detachment as “primary vitrectomy” — a term that initially implied that scleral buckling is the “gold standard.” Using vitrectomy as “rescue therapy” is said to be “conservative,” but it can produce the unintended consequence of delaying adoption of improved therapies and adding an additional procedure.

There are few, if any, high-quality clinical trials comparing vitrectomy, buckling and vit-buckle procedures for rhegmatogenous retinal detachment surgery. The lack of clinical trials with level 1 evidence has occur red largely because there are a large number of clinical variables, and many treatment options often used in combination.

Preoperative findings include type of breaks, size of breaks, number of breaks, lens status, refractive error, vitreous hemorrhage, vitreous traction, family history, status of the other eye, medical status and presence of lattice degeneration or retinoschisis. Options in scleral buckling include hard silicone vs sponges, subretinal fluid drainage vs non drainage, radial vs circumferential elements, encircling vs segmental buckles, use of air or gas, paracentesis, etc. Options in vitrectomy include air, SF6, C3F8, or silicone oil, laser vs cryo, 20-, 23- or 25-gauge, use of liquid perfluorocarbons, combined lensectomy or phacoemulsification, postoperative positioning, and many others.

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.

COMPLICATIONS OF SCLERAL BUCKLING

Encircling elements induce 2.75 D of myopia on average. Patients spend substantial amounts of money to eliminate refractive error; LASIK, PRK and refractive lens exchange have raised patients’ expectations of life without glasses or contacts. Cataract surgery patients expect emmetropia as well; substantial research and product development, as well as marketing efforts, have created patient enthusiasm for toric, multifocal and accommodating (albeit minimally accommodating) intraocular lenses.

Advances in cataract surgery addressing improved refractive outcomes include the development of techniques including optimized wound-construction, femtosecond laser coupled to 3D OCT, wavefront technologies and intraoperative aberrometry. All of these advances are rendered useless if an encircling element is utilized.

A prospective trial reported by the late Ron Michels, an excellent surgeon, demonstrated a 50% incidence of increased tropias and phorias and a 25% incidence of reduced forced duction amplitudes. Encircling buckles and segmental superior buckles may result in damage to the superior oblique tendon producing problematic vertical strabismus.

Excessive traction on retromuscle traction sutures, especially with small-diameter sutures, can damage the intraocular muscle tendons. Encircling bands are used frequently, although a circumferential, segmental buckle can produce the same reattachment rate in many detachment cases with out inducing myopia. Elimination of the encircling band minimizes damage to extraocular muscles, as well as damage to the levator aponeurosis, which may result in ptosis.

Overly aggressive stripping of the intramuscular septum, Tenon’s capsule and episclera combined with bipolar diathermy can create adhesions, which restrict ocular motility. Imprecise suturing of the conjunctiva, resulting in conjunctival redundancy, leads to ocular surface disorders and persistent corneal epithelial defects, especially if the epithelium is removed, as well as dellen and symblepharon.

Additional complications of scleral buckling include late intrusion of the buckle, buckle extrusion and infection. Intra operative complications include a 5% incidence of bleeding at the drainage site when using cut-down drain age, as well as a significant incidence of retinal incarceration in the drainage site. Scleral, choroidal and retinal perforation with scleral sutures is not uncommon either.

COMPLICATIONS OF VITRECTOMY

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. Nancy Holekamp has shown that vitrectomy results in a significant and permanent increase in oxygen tension in the vitreous cavity and a huge decrease in ascorbic acid content; nuclear sclerosis is an oxidative chemical reaction. The concept of vitrectomy causing nuclear sclerosis is not about being older than 40 or 50; it is about pre-existing nuclear sclerosis.

Posterior subcapsular cataract after vitrectomy is caused by gas bubble contact with the posterior lens surface, inadvertent lens bump, poor quality infusion fluid, or potentially the use of additives in the infusate. Facedown compliance is obviously much more likely with SF6 than with the much longer duration C3F8; therefore, I no longer use C3F8. The anterior vitreous cortex should not be removed in phakic cases; it protects the lens against gas cataracts. The anterior vitreous cortex should not be removed in IOL cases post-YAG because IOL fogging will result during fluid-air exchange.

The incidence of endophthalmitis after vitrectomy is 10% or less than the incidence after cataract surgery. My personal incidence is 3/29,000, no cases with 25-gauge vitrectomy, and no cases at all in the last 20 years. Conjunctival displacement, 30° scleral tunnel construction, elimination of vitreous wicks and povidone-iodine prep are essential elements of endophthalmitis prevention.

TECHNOLOGIES ENABLING VITRECTOMY REPAIR OF RETINAL DETACHMENT

Many technologies and techniques enable successful vitrectomy repair of retinal detachment without scleral buckling. Removal of vitreoretinal traction on all retina breaks and thin areas is essential and only possible with adequate visualization. Wide-angle visualization and illumination technologies have changed the paradigm of vitrectomy repair of retinal detachment, obviating the need for scleral buckling.

Contact-base wide-angle visualization (Volk, AVI) provides 10° more field of view than non-contact wide-angle systems (BIOM, EIBOS, ReSight). In addition, contact-based wide-angle visualization eliminates all corneal asphericity (RK, LRI, LASIK, pterygium removal, phaco, forme fruste keratoconus).

Noncontact wide-angle optical systems require much more ocular movement to visualize the periphery, which often drives more use of time-consuming and inconvenient scleral depression. I have rarely used scleral depression since contact-based wideangle visualization systems became available. The use of sutured contact lenses makes no sense with sutureless, transconjunctival vitrectomy. Why damage the conjunctiva?

Use of the highest possible cutting rates (5,000 cuts/minute or greater) reduces pulsatile vitreoretinal traction, which is mandatory in retinal detachment cases but essential for all tasks and all cases. I oppose the use of 3D and dual linear control strategies be cause of increased vitreoretinal traction and iatrogenic retinal breaks resulting from decreasing cutting rates during so-called core vitrectomy.

Endolaser retinopexy (Figure 1) is essential for retinal detachment cases. Although some surgeons use LIO during vitrectomy, this approach has many disadvantages: light scattering by the lens and cornea; inadvertent damage to the iris; slower, less precise operation; cervical spine issues for surgeon; and the need for sterile condensing lenses, which often provide poor view because sterilization destroys the antireflective coating. The LIO method also increases operating time and therefore labor costs.

Figure 1. Endolaser retinopexy is essential for detachment cases. Subretinal fluid should first be drained with a soft-tip cannula.

Soft-tip cannulas are ideal for internal drainage of subretinal fluid; there is less likelihood of retinal, RPE or choroidal damage if the patient moves under local anesthesia than with rigid cannulas. The 25-g soft tip can be inserted through the retinal break or drainage retinotomy well into the subretinal space and can even be directed toward a pocket of subretinal fluid (Figure 2).

Figure 2. Bipolar cauterization should be performed before retinotomy. The retinotomy can be made with a single pulse cut.

Perfluorocarbon liquids, such as PFO, are essential for giant retinal breaks. Although PFO can be used in all retinal detachment cases, this approach increases cost; simultaneous internal drainage of subretinal fluid and fluid-air exchange obviate the need for PFO in most cases. PFO is advantageous if IOL fogging occurs because of prior YAG capsulotomy and disruption or removal of the anterior vitreous cortex. I avoid using PFO in PVR cases because of the all too common problem of subfoveal PFO.

SUMMARY

Just as cataract surgeons have progressed from ICCE to ECCE to small-incision phaco with new technology, foldable IOLs and are now moving toward femtosecond-assisted OCT-guided cataract surgery, the vitreoretinal surgeon must move forward. The future is 25- or 27-g vitrectomy for the repair of retinal detachment without scleral buckling. High cutting rates, contact-based wide-angle visualization, endolaser retinopexy, PFO if needed, and a variety of new tools make this essential transition possible. RP



Retinal Physician, Volume: 9 , Issue: March 2012, page(s): 63 - 65