A rationale for membrane peeling in the repair of stage 4 macular holes

Abstract

Aim To examine the histological and immunocytochemical characteristics of epiretinal membranes (ERM) associated with stage 4 macular holes (MH) so as to establish a vitreoretinal rationale for surgery in stage 4 MH. Method Consecutive patients with stage 4 MH undergoing vitrectomy and membrane peeling were recruited. Preoperatively, the eyes were examined for ERM formation over the macula and completeness of posterior hyaloid membrane (PHM) separation from the retina. ERM peel specimens obtained during surgery were sent for histological and immunocytochemical studies and were compared with the PHM specimens taken from a previous post-mortem study of eyes with physiological posterior vitreous detachment but without macular holes. Result A total of 13 patients with stage 4 MH fulfilled the inclusion criteria and were recruited. Preoperatively, all eyes had an ERM over the macula and incomplete separation of the PHM seen as a defect in the PHM on specular biomicroscopy. Histologically, the ERM specimens had very similar morphological characteristics to PHM, consisting of an eosinophilic membrane of varying thickness with scattered spindleshaped cells. The membranes stained positively for type IV collagen while the cells were glial fibrillary acidic protein positive. Postoperatively, successful closure of MH was achieved in all cases. Conclusion Stage 4 MH is characterised by incomplete separation of the PHM from the retina with remnants overlying the macula manifesting as ERM. Removal of the ERM is required during vitrectomy in order to relieve the tangential forces involved in the development of MH.

Reply to Robbie and Snead

“…5 In our study, 10 of 23 cases had macular TA staining, and none developed visible macular ERM, and those seven postoperative ERM cases did not had intraoperative TA staining in the corresponding area. Although PHM may be important in the formation of ERMs in other vitreoretinal diseases, such as stage 4 macular hole, 6 our study results suggest that residual hyaloid may not be a necessary factor for the development of ERMs in eyes with RD.…”

Intravitreal triamcinolone staining observation of residual undetached cortical vitreous after posterior vitreous detachment

“…4,5 It has also become clear that the presence or absence of a Weiss ring is insufficient for the diagnosis of complete separation of PHM. 4,5 The authors allude to the possibility of 'undetached hyaloid fragments' being related to future epiretinal membrane (ERM) formation, but recent research suggests that the evidence for PHM in this role is particularly strong. 5 Incomplete separation of the PHM, rather than the cortical gel it envelops, would explain why seven patients in the study developed ERM without any associated residual vitreous staining (with one developing severe macular pucker).…”

“…Based on their histopathological studies of PHM and epiretinal membrane (ERM), 3,4 the authors suggest that the ERMs developed in seven cases in our series come from undetached PHM. Ultrastructural studies of ERMs found various types of cells within the membranes, including fibrous astrocytes, fibrocytes, macrophages, and even retinal pigment epithelial cells.…”

“…We do not think that adding a table showing logMAR visual acuities would have added to our message from this small case series that in certain cases visual acuity could decline fairly rapidly in spite of a 'successful' PDT treatment. The histology, immunohistochemistry, and ultrastructure of the posterior hyaloid membrane has been extensively described, [2][3][4][5][6] and recent research has highlighted its role in the pathogenesis of many vitreoretinal disorders, including macular holes, cellophane maculopathy, macular pucker, and vitreomacular traction syndrome. 4,5 It has also become clear that the presence or absence of a Weiss ring is insufficient for the diagnosis of complete separation of PHM.…”

“…The histology, immunohistochemistry, and ultrastructure of the posterior hyaloid membrane has been extensively described, [2][3][4][5][6] and recent research has highlighted its role in the pathogenesis of many vitreoretinal disorders, including macular holes, cellophane maculopathy, macular pucker, and vitreomacular traction syndrome. 4,5 It has also become clear that the presence or absence of a Weiss ring is insufficient for the diagnosis of complete separation of PHM. 4,5 The authors allude to the possibility of 'undetached hyaloid fragments' being related to future epiretinal membrane (ERM) formation, but recent research suggests that the evidence for PHM in this role is particularly strong.…”