Histological and Ultrastructural Examination of Internal Limiting Membrane Peel in Postmortem Autopsy Eyes

Abstract

Abstract: : Purpose: Internal limiting membrane peel has been advanced as a technique for improving outcome in macular hole surgery. Pathological study in reported cases has been limited to examination of the excised membrane by light and electron microscopy, with only a single illustration of the effect of the procedure on the remaining retinal tissue. We have studied five eyes removed postmortem and subjected to indocyanine green injection and internal limiting membrane peel. Methods: Five eyes removed postmortem were subjected to localized posterior vitrectomy, indocyanine green injection and internal limiting membrane peel within thirty-six hours of death. The excised membrane was placed in glutaraldehyde fixative, embedded in epon, and one micron sections generated were stained with methylene blue for light microscopic examination. Thin sections were obtained and stained with uranyl acetate and lead citrate and examined by transmission electron microscopy. The postoperative whole eyes were fixed in 10% neutral buffered formalin, paraffin embedded, and five micron sections were stained with H&E and PAS for light microscopic examination. Results: The excised membranes were confirmed to be basal laminae by ultrastructural examination. The vitread surface was smooth, but the retinad surface was irregular, with adherent fragmented and circular cellular membranes. Histopathological examination of the eyes showed variable degrees of detachment of the internal limiting membrane from the nerve fiber layer at the margins of the excision sites. The free edges of the internal limiting curled toward the vitreous. Beyond the edges of the detachment, the retinal architecture was generally unremarkable. In the areas devoid of internal limiting membrane, the inner retinal surface was irregular and showed vitread displacement of ganglion cells, most noticeably in areas where the nerve fiber layer was thin. Retinal photoreceptor outer and inner segments were preserved with minimal to absent autolytic degeneration. Conclusions: Internal limiting membrane peel in postmortem eyes may cause detachment of the remaining internal limiting membrane beyond the edges of the peel. Presence of cellular elements on the peeled membrane, irregularity of the peeled retinal inner surface, and ganglion cell displacement by the procedure may possibly be an explanation for reported visual disturbances following internal limiting membrane peel.

Keywords: retina • vitreoretinal surgery • microscopy: electron microscopy