The effect of silicone ocular surgical devices on serum IgG binding to silicones

Massive Silicone-Induced Orbital Granuloma

We report a large subconjunctival-orbital granuloma in a 51-year-old male presenting with a blind painful right eye and marked chemosis 15 months after undergoing vitrectomy and silicone oil retinal tamponade for retinal detachment with no reported intraoperative complications. Gross and histopathologic examination of the enucleated eye and episcleral tumor revealed a bosselated mass measuring 17 × 10 × 5 mm containing prominent vacuoles with surrounding epithelioid histiocytes and foreign body multinucleated giant cells. Such a large silicone-induced orbital granuloma following uncomplicated retinal surgery in a grossly intact eye has not been previously reported to the authors' knowledge. High intraocular pressure and emulsification of oil may facilitate silicone extravasation through scleral wounds after retinal surgery.

Multinucleated giant cells in periretinal silicone granulomas are associated with progressive proliferative vitreoretinopathy

PURPOSE

To determine the histologic features of granulomatous reactions in persilicone periretinal proliferation.

PATIENTS AND METHODS

This retrospective study included 12 patients with recurrent retinal detachment and persilicone granulomatous proliferation after vitrectomy for proliferative vitreoretinopathy (PVR). All patients underwent reoperation for membrane surgery. Immunohistochemical study of the excised periretinal membranes was performed with cytokeratins, GFAP, vimentin, CD68, CD45, and lysozyme antibodies.

RESULTS

The cellular characteristics of periretinal granulomas allow differentiation of two types of tissue. Spongy tissue (nine cases) showed an accumulation of mature vacuolated macrophages that contained silicone without multinucleated giant cells (MGC). The second type (three cases) consisted of an accumulation of sparsely vacuolated macrophages, epithelioid cells, and MGC. The MGC corresponded to transition forms of foreign body giant cells (FBGC). Spongy tissue was associated with anatomic success (58.3% of cases) and with stabilized PVR (66.7% of cases) at the time of the membrane surgery. MGC were associated with prolonged silicone oil tamponade, recurrent retinal detachment, and progressive PVR.

CONCLUSIONS

Intraocular silicone oil can lead to periretinal foreign body granulomas. FBGC are occasionally observed and were associated with progressive PVR.

The measurement of conformational stability of proteins adsorbed on siloxanes

The paper investigates the conformational stability of bovine serum albumin (BSA) and fibrinogen during 24-h incubation in turn with a linear silicone polymer (polydimethylsiloxane (PDMS)), with linear silicone oligomers (hexamethyldisiloxane and octamethyltrisiloxane) and with cyclic silicone oligomers (octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5)). Ten-fold and 100-fold excesses of siloxanes with respect to the proteins were used. Using fluorescence spectroscopy of tryptophan located in the domain of proteins and fluorescence of 8-anilino-1-naphthalenesulfonic acid (1,8-ANS), which interacts with hydrophobic domains of proteins, changes in the tertiary structure of the protein were recorded. The results demonstrated that BSA does not change its native form during 24-h incubation with siloxanes. In contrast, the tertiary structure of fibrinogen was found to be altered by both short-chain linear siloxanes: (hexamethyldisiloxane and octamethyltrisiloxane) and long-chain PDMS. The changes can be observed only at a 100-fold excess of siloxanes with respect to the protein. No conformational changes in fibrinogen exposed to cyclic siloxanes were observed.

Foreign body episcleral granulomas complicating intravitreal silicone oil tamponade: a clinicopathological study

PURPOSE

To report two patients with lipid granulomas of the episclera complicating vitrectomy and silicone oil tamponade.

DESIGN

Two observational case reports.

INTERVENTION

Patient 1, a 41-year-old woman, underwent vitrectomy with silicone oil tamponade for proliferative diabetic retinopathy. Four weeks later, she sought treatment for inflamed episcleral nodules adjacent to one of the sclerostomy sites. The oil was removed and the episcleral nodules were excised. Patient 2, a 33-year-old man, underwent vitrectomy and silicone oil tamponade for tractional retinal detachment. He experienced a painful blind eye with episcleral nodule that required enucleation.

MAIN OUTCOME MEASURES

On histopathological analysis, both specimens demonstrated episcleral granulomas caused by silicone oil.

CONCLUSIONS

Episcleral nodules adjacent to vitrectomy entry sites with silicone oil tamponade may represent lipid granulomas, probably caused by silicone oil leakage from scleral entry ports.

Setons and serum IgG titers to silicone

PURPOSE

To determine whether exposure to silicone shunts used in refractory glaucomas increases serum IgG binding to silicone and whether this response is associated with shunt-related complications or poor postoperative intraocular pressure control.

METHODS

Sera from 12 patients (13 eyes) who had undergone placement of silicone seton implants were examined for IgG binding to silicone. Patients were monitored postoperatively for the occurrence of complications and intraocular pressure elevation (mean duration of exposure to silicone and follow-up, 25.1 months; range, 2.5-86 months).

RESULTS

The levels of serum IgG binding in 4 of the 12 patients were two standard deviations above the mean for control sera. No patients had titers greater than 46 arbitrary units (AU). Four patients developed shunt-related complications; the serum IgG binding to silicone for their sera ranged from 24 to 46 AU. Serum IgG binding values were not significantly correlated with poor postoperative intraocular pressure control, or with a history of autoimmune disease or malignancy, type of glaucoma, previous intraocular surgery, or chronic uveitis.

CONCLUSIONS

Although elevation of serum IgG binding to silicone may be noted in some patients receiving silicone seton shunts, individual levels do not seem to predict the development of shunt-related complications. Since the number of patients tested, the frequency of elevated IgG binding values, and the complication rate were relatively low in this study, it is difficult to exclude some clinicopathologic correlations. However, the results are in accord with previous studies of silicone ocular devices suggesting that clinically significant reactions to silicone ophthalmic implants must be rare events, and hence do not necessitate altering the use of these important devices.

Antisilicone antibodies in patients with silicone implants for retinal detachment surgery

A modified ELISA assay was used to detect IgG binding to silicone and IgG subtypes in serum of patients bearing silicone bands, silicone sponges and intraocular silicone oil. Presence of autoantibodies (rheumatoid factor, antinuclear antibody, and SCL 70) and signs and symptoms of autoimmune diseases were also checked. Antisilicone antibodies were detected in 35.7% of patients with solid silicone and in 83% in those with silicone oil. This increase in IgG is mainly due to IgG1. Nevertheless no positive results were found in detecting signs and symptoms of autoimmune diseases.