The role of membrane-inner retina adherence in predicting simultaneous internal limiting membrane peeling during idiopathic epiretinal membrane surgery.

PurposeTo correlate the frequency and extent of simultaneous inadvertent internal limiting membrane (ILM) peeling during idiopathic epiretinal membrane (ERM) removal with characteristics of ERM adherence demonstrated on pre-operative spectral domain optical coherence tomography (SD-OCT).Patients and methodsThis is a prospective, observational, case series of patients undergoing pars plana vitrectomy for idiopathic ERM. Inner retina-ERM adhesion was categorized as focal, broad or complete in five anatomic locations at macular area based on preoperative SD-OCT findings. The extent of spontaneous ILM peeling was quantified on a scale 0-100% in each of the aforementioned anatomic locations by the operating surgeons who were masked to the OCT characteristics. All operations were recorded with a high definition recording system and the area of simultaneous ILM peel was quantified by a second masked observer. The final extent of spontaneous ILM peel was calculated as the average of the two scores.ResultsThirty consecutive subjects who underwent surgery for idiopathic ERM were included in the study. Evidence of simultaneous ILM peeling was identified in 80.3% of individuals. With regards to the type of ERM-macula adhesion, inadvertent ILM peel was observed in 70% of the patients who pre-operatively showed complete adhesion, in 43% with broad adhesion and in only 21% with focal adhesion (P<0.001). The extent of the spontaneous ILM peel during removal of ERM was also significantly dependent on the type of ERM-inner retina adhesion. Total simultaneous ILM peel was observed in 59% of locations with complete ERM-macula adhesion but only in 22% and 7% of locations with broad and focal adhesion respectively (P<0.001).ConclusionsSimultaneous ILM peel is a frequent occurrence during ERM surgery, especially when there is complete or broad ERM adherence to the macula. The type of ERM-inner retina adhesion represents a valid predictor of the extent of simultaneous ILM peel during removal of ERM. Thorough evaluation of preoperative OCT may be a useful tool in determining a safer, more simplistic strategy in ERM surgery.