Article Date: 5/1/2007

Untitled Document

Surgical Intervention for Retinal Detachment
STEPHANIE L. VANDERVELDT, MD • TIMOTHY G. MURRAY MD, MBA

A 16-year-old male presented to the emergency room several weeks following blunt ocular trauma sustained in a BB-gun shooting. On presentation, a traumatic cataract obscured the view to the posterior pole. Echography showed a retinal detachment with proliferative vitreoretinopathy (PVR).
SCLERAL BUCKLING, PRIMARY PPV, OR COMBINED PROCEDURE

Traditionally, scleral buckle placement (SBP) is the first-line treatment for the repair of primary rhegmatogenous retinal detachment (RRD), particularly with inferior retinal pathology. In the repair of giant retinal tears, however, the use of pars plana vitrectomy (PPV) alone or in combination with SBP has been a mainstay.With improved instrumentation and fluidics, wide-angle viewing systems, lighting technology, heavy perfluorocarbon liquids, and transconjunctival surgery, the use of PPV has increased exponentially. This includes the use of PPV for the repair of RRD without the concomitant placement of a buckling element. The surgeon’s ultimate choice of surgical technique will depend on a variety of factors, including lens status, break location, presence of PVR, available surgical equipment, and surgeon comfort with either procedure. The use of SBP in combination with PPV may provide the best opportunity for single-operation success. The use of a buckling element provides support for “missed” retinal breaks or additional breaks present at the time of PPV while allowing improved ability to dissect anterior vitreous to release traction overlying retinal pathology. The patient presented above underwent SBP+PPV for repair of his complex pathology.While several retrospective, nonrandomized case series have been published comparing single-operation success rates of SBP with PPV for repair of RRD, the data are confounded by the fact that most of these reports include combined procedures (SBP+PPV) in the PPV data set.1



Stephanie L. Vanderveldt, MD, is a vitreoretinal surgery fellow at Bascom Palmer Eye Institute of the University of Miami. Timothy G. Murray, MD, MBA, is professor of ophthalmology at Bascom Palmer. Neither author has any
proprietary interest in any products mentioned in this article. Dr. Vandervelt can be reached via e-mail at SVanderveldt@med.miami.edu.


WIDE-ANGLE VIEWING SYSTEMS
The use of wide-angle viewing systems allows superior viewing of the peripheral retina when compared to traditional planoconcave or biconcave lens systems.2 The use of either a contact wide-angle system or a noncontact wide-angle system, such as a binocular indirect ophthalmomicroscope, provides a superior view of the peripheral retina.We routinely employ a contact wide-angle system that provides visualization of the retina, facilitating peripheral vitreodissection and PVR removal.
SMALL-GAUGE SURGERY
Transconjunctival small-gauge vitrectomy systems are rapidly becoming a mainstay in retinal surgery. One drawback of 25-g systems in retinal detachment repair may be the relative difficulty of peripheral visualization due to limitations of instrument rigidity. Newer 23-g systems, however, provide improved instrument stiffness and improved ability to rotate the globe for adequate viewing of the vitreous base and retinal periphery. Unfortunately, the transconjunctival approach is obviated when concurrently utilizing a scleral buckling element. With the conjunctiva released, there is limited benefit of small-gauge instrumentation over traditional 20-g technology.
ILLUMINATION

While small-gauge surgery may be of limited value in combined SBP+PPV, this new trend has fostered improved technology in operative lighting systems that can be applied to 20-g procedures as well. The use of xenon light sources coupled with illuminated instrumentation, dual-mode infusion cannulae, and separate supplemental illumination sources (chandeliers and multiport illumination systems) now provide improved visualization previously unattainable. Complex PVR retinal detachments, diabetic tractional retinal detachments, and giant retinal tears may now be addressed with a true bimanual approach.We favor the use of a lighted infusion cannula to provide additional illumination for difficult cases such as the one described.
INTRAOCULAR TAMPONADES
The use of silicone oil and expansile gases as endotamponades following retinal detachment repair is routine. Gas endotamponade provides the luxury of retinal support while eliminating the need for a second procedure to remove the tamponade at a later date. The disadvantages of gas tamponade, however, include visual limitation during the postoperative period and the contraindication of airplane travel while gas is present. Both silicone oil and intraocular gas increase the risk of cataract development and postoperative hypotony. Silicone oil provides a longer-acting vitreous substitute for more complicated retinal-detachment repair. The advantages of silicone oil also include faster visual recovery without travel restrictions. The disadvantages of silicone oil, however, are multifold. A second oil-removal procedure is necessary, and the secondary retinal-detachment rate is not negligible. Also, there is a significant incidence of secondary glaucoma, both open- and closed-angle, with silicone oil use, as well as the potential for band keratopathy development. Silicone oil may emulsify with long-term retention. Finally, the potential for inferior PVR formation in regions of the retina not covered by oil, where fibroblasts and cellular debris may accumulate in the aqueous phase, is another disadvantage to its use.
HEAVIER-THAN-WATER ENDOTAMPONADE
Perfluorocarbon liquids are occasionally used as an inferior tamponade for several days to 2 weeks with later removal and replacement with gas or silicone oil.3 The disadvantages of this technique include the need to return to the operating room soon after the initial surgery, limited visualization, corneal edema, anterior chamber droplet formation, glaucoma, potential retinal and vascular toxicity, and difficulty in removal of the agent. Heavy fluorocarbon liquids are partially hydrogenated perfluorocarbons, modified to decrease specific gravity (reducing retinal toxicity) and increase lipophilicity of the agent (causing miscibility with silicone oil). These can be used as silicone oil solvents for removal of retained oil droplets adherent to intraocular lenses and anatomic structures. The long-term use of heavy fluorocarbons yields similar complications as perfluorocarbons.4 Experience mixing heavy fluorocarbons and silicone oil prior to instillation has led to the development of what has been termed heavy silicone oil.5 Limited clinical experience with this agent has suggested similar PVR formation risks as traditional silicone oil, however, localized to the superior retina.6 A European multicenter study, the “Heavy Silicone Oil” study is underway investigating the use of Densiron 68. The prospect of a heavier- than-water endotamponade to aid in the repair of inferior pathology and reduce the need for face down positional compliance is intriguing, though further study is needed to explore the efficacy of available agents.
CONCLUSION
The technology of PPV continues to evolve, allowing improved outcomes in more complex cases of retinal detachment. Improvements in visualization and illumination, tissue manipulation, and endotamponade allow the surgeon greater versatility to address the specific needs of the patient and tailor the surgical approach to each case.While there are several exciting developments under investigation and currently in use to facilitate vitrectomy-assisted retinal detachment repair, there remains a profound utility to the scleral buckle procedure. Further still, these techniques, when used in combination, may provide the highest likelihood of single-operation success. The patient presented herein underwent SBP+PPV with removal of a traumatic cataract, peeling of PVR membranes, and instillation of silicone oil. He recovered nicely and 4 months later underwent a second procedure to remove the silicone oil, peel limited perisilicone membrane formation, and place a secondary intraocular lens. At 5-year follow-up, his vision was 20/50, and his fundus photo is presented in the Figure on page 61.

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Retinal Physician, Issue: May 2007