The (Flip and Fix) Internal Limiting Flap Technique Versus the Classic Temporal Flap for Macular Hole Repair

We conducted a prospective randomized comparative interventional study in which we enrolled patients older than 50 years with idiopathic macular holes who presented to (Removed in the blinded version of manuscript) in the period between February 2021 and February 2022. Patients with previous macular surgeries and those with any other significant macular pathologies e.g., diabetic macular oedema, myopic maculopathy, choroidal neovascular membrane, or macula-off retinal detachment were excluded.

The study protocol was reviewed and approved by the Ethics Committee of (Removed in the blinded version of manuscript). All patients signed an informed consent after explaining the procedures. The study was conducted in accordance with the tenets of the Declaration of Helsinki.

For all the patients, a retina consultant (I. A.) masked to the procedure that will be done for the patient conducted a comprehensive ophthalmic examination, including best-corrected visual acuity (BCVA) (measured using the Snellen's chart and then converted to the LogMAR for the statistical analysis), slit-lamp examination, and fundus examination.

All the patients had a pre-operative macular OCT scan done. The scans were assessed by the masked retina consultant (I. A.) to confirm the diagnosis and to measure the minimum MH diameter.

The included patients were randomized by a research nurse on a 1:1 basis using the closed envelope technique to have either the new (Flip and fix) technique (Group A) or the PFCL assisted temporal inverted ILM flap technique (Group B).

All the surgeries were done under general anaesthesia by a single surgeon (M. A.) using a wide-angle viewing non-contact system (Resight; Carl Zeiss Meditec AG, Jena, Germany) and 23 Gauge Alcon Constellation vitrectomy machine (Alcon Laboratories, Fort Worth, TX) to complete the core vitrectomy and induction of the posterior vitreous detachment if not already detached, this was followed by an injection the Brilliant Blue G (Tissueblue 0.025% DORC, Zuidland, The Netherland) to stain the ILM.

In both groups, a single-layer ILM temporal flap of approximately 2 times the size of the optic disc was fashioned using an ILM forceps temporal to the macula. The nasal edge of the flap was not detached from the temporal MH edge. The flap was reflected nasally to cover the MH In the (Flip and Fix) technique group, the (flipped) ILM flap was secured in place and flattened over the macular surface using a 1.5 cc bubble of PFCL (Arcaline; Arcadophtha, Toulouse, France) injected over the flipped ILM flap. Then fluid air exchange with removal of the PFCL bubble was done followed by (fixing) the ILM flap over the macular surface using two drops of autologous non-heparinized blood -collected by the attending nurse or anaesthesiologist from one of the veins on the dorsum of the hand- one dropped over the superior-nasal and another at the inferior-nasal edges of the ILM flap (away from the MH center). On the other hand, in the classic temporal ILM flap group, PFCL and blood were not used to fix the ILM flap. Videos demonstrating the technique are provided as supplemental files 1 and 2.

In both groups, at the conclusion of the surgery the air was exchanged for a non-expansile concentration (20%) of sulphur hexafluoride gas SF6 and the patient was asked to maintain a face -down position for 5 days postoperatively. The surgical steps of the (flap and fix) technique are summarized in Figure 1.

For all the cases, intraoperative ILM flap displacement (defined as a significant displacement of the inverted ILM flap after its initial positioning over the MH that necessitated readjustment) was reported by the operating surgeon.

All the patients were examined postoperatively at 1, 3, and 6 months by a retina consultant masked to the used surgical procedure (I. A). The best corrected visual acuity, slit-lamp examination, fundus examination and macular OCT scanning were done in each postoperative visit.

According to the cross-sectional morphology on the postoperative macular OCT scan, foveal contour was classified into one of the following categories: U-shape, V-shape, and W-shape (irregular). The presence of a thin hyperreflective band of tissue extending on both sides of the previous MH Flap between the inner surface of the retina was assessed and considered a (membranous i.e., flap closure).

The data about the pre-operative MH base size, minimum MH diameter, BCVA, post-operative closure rate, BCVA, and the pattern of the MH closure was collected.