Encapsulation of Scleral Buckling Materials A Study of Sixty Specimens Frangois D’Herrnies, MD, ’ Jean-Frmqois Korobelnik, MD,2 Georges Qmto, MD,’ Babak Mashhour, MD,’ Dominique Chuuuaud, MD, ’ Yves Pot&pen, MD, ’ Gilles Renard, MD’ Objective: The purpose of the study was to obtain information on the encapsulation of two nonabsorbable biomaterials (silicone and hydrogel) used as explants in scleral buckling in retinal detachment surgery. Design: The study design was a histopathologic study on a cohort of capsule fractions and complete eyes. Participants: Fifty-nine patients participated in this study, in which 60 specimens, including 37 hydrogel and 21 silicone capsule specimens as well as 2 whole eyes, were gathered. There were no control subjects. Intervention: The capsule specimens were obtained from eyes operated on previously for scleral buckling for retinal detachment. The two whole eyes were enucleated. All specimens were studied with routine optic microscopy. Main Outcome Measures: Patient characteristics, type of scleral buckling, and number of operations performed were analyzed. Histologically, the capsular structure, its interface with the explant, and its different components also were studied. Remnants of the buckling material also were investigated. Results: There were 45 male and 14 female patients, with a mean age of 49 years. Histologically, capsule specimens had a fibrous matrix with fibroblasts and few inflammatory cells. Eighteen (48.6%) of 37 hydrogel capsule specimens displayed hydrogel fragments surrounded by a foreign body giant cell granuloma in 16 cases. Conclusion: Nonabsorbable materials undergo encapsulation after implantation on the eye surface. Giant cell granuloma was observed in some hydrogel capsule specimens in relation to hydrogel fragmentation. The exact origin of this fragmentation remains unknown. Ophthalmology 7998; 705:7079- 7086 Almost all nonabsorbable biomaterials undergo a progres- sive encapsulation after implantation in tissues. This phe- nomenon also is observed in the episcleral explants used for retinal detachment surgery. Encapsulation results in the formation of a fibrous capsule, which represents a barrier between the host tissue and the implanted material. The capsule provides isolation of the material and some- how protects it from infection. However, the capsule does not protect the implanted material completely from changes induced either by mechanical strains or by chemi- cal aggression. We already found through experimenta- tion that one previously and often used scleral buckling biomaterial, a hydrogel (Miragel, Mira Inc., Waltham, MA), underwent a microscopic breakdown displayed as visible fragments located on the inner surface of the cap- sule encasing the material.’ To investigate the incidence Originally received: December 17, 1996. Revision accepted: December 1, 1997. ’ Department of Ophthalmology, HBtel-Dieu, Pans, France. * Department of Ophthalmology, HBpital Bichat, Pans, France. Presented in part at the Annual Meeting of the Association for Research m Vision and Ophthalmology, Sarasota, Florida, May l-6, 1994; and at the Joint European Research Meeting in Ophthalmology and Vision, Montpelher, France, October 15- 19, 1994. The authors have no proprietary interest in the development or marketing of the mentioned scleral buckling materials. Reprint requests to Franqois D’Hermies, MD, Department of Ophthal- mology, HateI-Dieu, 1 Place du Parvis Notre Dame, F-75181 Paris cedex 04, Paris, France. of this change in clinical practice, we performed an analy- sis of capsule specimens obtained during surgical proce- dures on eyes implanted previously with different types of biomaterials. Materials and Methods We studied all the specimens coming from eyes implanted pre- viously with scleral buckling material available in our labora- tory from June 1991 to May 1995. Sixty specimens were col- lected from 59 patients, of which one female patient (specimens 15 and 54) underwent an encircling scleral buckle on both eyes for bilateral retinal detachment. These specimens included 58 parts of capsule and 2 whole eyes enucleated after a previous retinal detachment surgery. Both eyes underwent half an encir- cling scleral buckle with silicone sponge that was removed macroscopically from both eyes before it suffered further patho- logic processing. Always obtained from eyes reoperated on for retinal detachment persistence or recurrence, the capsule speci- mens were collected during surgical procedures modifying the previously placed scleral buckling. They were fixed in Bouin’s aqueous solution immediately after surgical removal to be stud- ied with routine histopathologic methods. All specimens were obtained for histopathologic study and finally stained with he- matoxylin-eosin (HE), periodic acid-Schiff, and Masson’s tri- chrome. Clinical Results The clinical results are summarized in Tables 1 and 2. Among the 59 patients in this study, there were 43 men, 2 boys, 12 1079