Clinical and histological evaluation of large macular hole surgery using the inverted internal limiting membrane flap technique

Abstract

Purpose: The aims of this study were to analyze optical coherence tomography (OCT) imaging of large macular holes (MHs) treated with inverted internal limiting membrane (ILM) flap technique and to perform a histological examination of an ILM-like membrane tissue obtained during vitrectomy.

Patients and methods: This is a retrospective observational case study. Nine patients, comprising of five males and four females, showing large and myopic MHs, underwent pars plana vitrectomy (PPV) with inverted ILM flap technique assisted by brilliant blue G (BBG) staining. Ophthalmological findings including visual acuity and OCT were investigated based on medical records. Formalin-fixed paraffin-embedded tissue section of an ILM-like membrane was submitted for immunohistochemistry with glial fibrillary acidic protein (GFAP).

Results: ILM was clearly stained with BBG in eight patients, whereas the ILM in one case revealed no staining with BBG during PPV. Visual acuities improved to >0.2 LogMAR in six patients. The complete closure of MH following PPV with inverted ILM technique was eventually achieved in all patients determined by OCT imaging (100%). Only one patient showed recovery of ellipsoid zone and interdigitation zone following the surgery. Elongation of outer nuclear layer was noted in three eyes. The ILM-like membrane not stained with BBG histologically revealed an amorphous structure admixed with GFAP-positive mononuclear cell infiltration.

Conclusion: PPV with inverted ILM flap technique achieved 100% closure rates with favorable configuration at an initial surgery in large MHs. Our histopathological data also suggest that even BBG staining-negative membrane may be a useful material for autologous transplantation to the hole.

Keywords: OCT; glial cells; histopathology; inverted ILM flap; macular hole.

Figure 1

Representative two cases (Case 1, A–D; Case 2, E–H) with old-large macular hole treated with pars plana vitrectomy and inverted internal limiting membrane (ILM) flap technique. Notes: In Case 1, a 71-year-old female presents with Stage IV large macular hole (A), measuring a minimum diameter of 623 µm (B). During vitrectomy, the ILM is stained with brilliant blue G (BBG), which was placed within the hole (C, arrows). Macular hole is successfully closed 3 months after the surgery (D). In Case 2, a 70-year-old female presents with Stage III large macular hole (E), measuring a minimum diameter of 789 µm (F). In intraoperative findings, ILM-like membrane without staining with BBG was placed within the hole in the vitrectomy (G, arrows). The macular hole is successfully closed 3 months after the surgery (H) as shown in Case 1.

Figure 2

Other OCT findings before and after vitrectomy with inverted ILM flap technique. Notes: OCT detects large macular hole in a patient with high myopia (A). Three months after the surgery, macular hole is successfully closed with a favorable configuration (B). The other patient reveals a large macular hole without high myopia (C). However, macular hole is closed with thin retinal tissues covering after the surgery (D). Abbreviations: OCT, optical coherence tomography; ILM, internal limiting membrane.

Figure 3

Hematoxylin and eosin (HE) staining (A), periodic acid Schiff (PAS) staining (B), and immunohistochemistry for glial fibrillary acidic protein (GFAP) (C) in the internal limiting membrane (ILM)-like membrane in a patient with large macular hole (Case 2). Notes: The ILM not stained with brilliant blue G reveals eosinophilic amorphous structures admixed with mononuclear cell infiltration (A). PAS staining shows negative for cell infiltration but positive for the amorphous structure in consistence with ILM (B). The mononuclear cells are GFAP-positive (C). (A) Bar equals 50 µm.