Kokame ea, 'Successful management of intruded hydrogel buckle with buckle removal, scleral patch graft, and vitrectomy', Retina 2003, nr. 4, p. 536-538   

Kokame ea beschrijft de intrusie van een gezwollen hydrogel implant, die aangebracht was onder een cerclagebandje, dat de implant belette naar buiten uit te zetten waardoor de zwellende implant de onderliggende sclera deed eroderen en uiteindelijk door de sclera het oog kon inkomen. De implant kon verwijderd worden en de sclera hersteld evenals het recidief netvliesdefect.

Hydrogel implants used for scleral buckling in retinal detachment surgery have been reported to develop swelling many years after the initial surgery.1 3 Secondary complications. including chronic discharge and granuloma formation 3, extrusion of the implant through the conjunctiva,2,3 double vision and restriction of ocular tnotility,2 and întrusion of the implant through the sclera, 1 may develop secondary to progressive buckle swelling. lntrusion of the buckle through the sclera into the subretinal space is a particularly difficult management problem and can result in severe vision loss, recurrent retinal detachment. and subretinal or vitreous hemorrhage. 1.4 In the five cases of hydrogel buckle intrusion with loss of vision reported by Marin and colleagues, l none of the patients recovered useful vision in the eye with or without surgical intervention.

Case Report
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Review of the operative report of the initial retinal detachment surgery showed that a MlRAgel meridional implant No. 907 (MIRA, Jnc., Uxbridge. MA) was used for localized support under a No. 280 circumferential solid silicone tire. These buckle elements had been placed into a partial-thickness dissected scleral bed and under scleral flaps.
Because the intruded buckle resulted in acute symptomatic vision loss and was encroaching over the central macula, buckle removal was recommended with a poor visual prognosis. The swollen hydrogel implant was restricted from outward expansion by an overlying circumferential tire, and the underlying sclera was thinned by scleral dissection. An external approach was planned for buckle removal with vitrectomy for secondary complications and a scleral graft available to patch any visible scleral defect. The scleral flaps were dissected off of the encircling tire, and the tire was removed in the superotemporal quadrant. The hydrogel sponge had intruded completely through the scleral bed into the eye. Because the buckle was extremely friable, it was removed by grasping the hydrogel buckle with a cryoprobe with a gentle side-to-side motion, while supporting the underside of the hydrogel buckle with a lens loupe to prevent further intrusion. The buckle element was removed intact and was noted to be much larger (approximately 11 x 11 x 5 mm) than its original size (7.5 x 5.5 mm). The eye became hypotonous with vitreous loss and an open scleral defect. (…)

Discussion
Hydrogel implants were initially thought to be good buckling elements, because of an effective buckling effect, the softness and elasticity of the original material, their lack of dead spaces possibly decreasing the risk of infection, their hydrophilic characteristics allowing absorption of antibiotic, and the stimulation of a fibrous capsule.5 However, late complications have been reported to develop due to progressive implant swelling. Marin et al1 reported seven cases in which long-term complications developed from swelling of the MAI hydrogel intrascleral buckling implant 7 to 10.5 years after placement. Laboratory evaluation confirmed chemical changes within the polymer of the implant, which changed from a soft, spongy, whitish material to a friable, gellike, cream-colored material.
The most severe complications were buckle intrusion, which occurred when supplemental hydrogel buckle elements were used under a solid silicone implant in a dissected scleral bed, similar to this reported case. All five patients with symptomatic vision loss and buckle intrusion had persistent poor vision with either observation or surgical attempts at repair, including cutting of the encircling band, buckle removal without vitrectomy, and vitrectomy with removal of the intruded implant from the vitreous. Hwang and Lim 2 reported a case of scleral buckle extrusion, swelling, and fragmentation associated with a MIRAgel episcleral explant. MIRAgel has the same chemical composition as MAI hydrogel buckles. Roldan-Pallares and colleagues 3 recommended periodic long-term follow-up for hydrogel implants because of long-term alterations in their chemical composition and eventual swelling, which resulted in late extrusion and discharge 7 to 10 years after placement.
The intrusion of buckle elements into the eye through the sclera results in subretinal and vitreous hemorrhages, recurrent retinal detachment, intrusion through the retina, possible complete loss of vision, and phthisis. Because of difficulty in management of this complication and the high risk of surgical intervention, observation has often been recommended.1,4 In this case and others with a hydrogel implant progressively swelling under an overlying tire and intruding through a thin scleral bed, surgical intervention is recommended. With successful removal of the swollen intruded implant, repair of the scleral defect using a scleral graft, and successful vitrectomy repair of the retinal detachment, this case demonstrates potential excellent vision recovery following visual rehabilitation after management of this difficult complication.