Macular hole (MH) diameter has a strong influence on postoperative anatomical and functional results. The inverted internal limiting membrane (ILM) flap technique improves anatomical and functional outcomes of vitrectomy for large MHs with a minimum diameter exceeding 500 μm.1 However, improvements in these procedures have not resulted in 100% satisfactory surgical outcomes. In some cases of idiopathic MHs, initial surgery using the inverted ILM flap technique fails to achieve MH closure, while the ILM has been previously removed in others. In such cases with refractory MHs, Morizane reported that autologous transplantation of the ILM resulted in a success rate of 90%.2 However, it is often difficult to harvest and place a suitably sized free ILM flap into the MH,3 and the procedure is relatively invasive to the retinal pigment epithelium and neural retina. To address this issue, we developed a new instrument that can harvest and push the free ILM flap safely and reliably into the MH.
Designed for 25-gauge vitreous surgery, the instrument has a 38-mm stainless steel shaft and a handle portion of 76 mm, which can be adapted to cases of high myopia (Figure 1). A 2-mm silicone tip at the end of the stainless steel shaft provides excellent flexibility and serves to reduce mechanical invasion to the retinal pigment epithelium and neural retina when placing the free ILM flap into the MH. The end of the silicone tip contains a spherical silicone component with a diameter of 480 μm, the shape of which ensures minimal adhesion of the free ILM flap (Figure 2). To facilitate smooth insertion into the trocar with the closure bulb, a movable stainless steel T-tube with an outer diameter of 0.9 mm, an inner diameter of 0.6 mm, and a length of 6.0 mm is installed on the shaft.
The residual ILM is stained with 0.025% Brilliant Blue G (BBG 250; Sigma-Aldrich, St. Louis, MO) to identify the area containing the remaining ILM. After creating a suitably sized ILM flap using vitreous forceps, the dispersed viscoelastic material is injected from just above the macula to the extent that it flows over the MH. The prepared ILM flap is peeled off, transported into the viscoelastic material on the MH using vitreous forceps, and attached (Figure 3). The contracted free ILM flap in the viscoelastic material is pushed and expanded into the MH using the new instrument (Figure 4), and fluid–air exchange is performed (see Video, Supplemental Digital Content 1, which demonstrates how to use this instrument, http://links.lww.com/IAE/A737). In all six cases, optical coherence tomography findings revealed that the postoperative ILM flap was present in the MH, and complete MH closure was observed in five cases. No adverse effects on retinal structure were noted in any case. The clinical use of this device was in full compliance with the guidelines of the Declaration of Helsinki and approved by the Institutional Review Board/Ethics Committee of Toho University Sakura Medical Center (S-16077).
Although autologous ILM transplantation is effective for the treatment of refractory MHs, various complications may occur during the procedure. The most difficult step of ILM transplantation involves the transportation and placement of the free ILM flap into the MH using vitreous forceps. Releasing the ILM after it has been grasped by the forceps is difficult, and the contracted free ILM flap is unlikely to remain in place. Although the use of vitreous forceps renders adherence to a free ILM flap less likely, the use of perfluorocarbon liquids during the surgery as described by Park et al4 may have a similar effect.
Herein, we report that the use of this new instrument allows for safe placement of the contracted free ILM flap into the MH in cases of refractory MH. Thus, this new instrument may improve the success rate of autologous ILM transplantation and facilitate safer placement of the inverted ILM or neurosensory retinal free flap5 into large MHs.
1. Michalewska Z, Michalewski J, Adelman RA, Nawrocki J. Inverted internal limiting membrane flap technique for large macular holes. Ophthalmology 2010;117:2018–2025.
2. Morizane Y, Shiraga F, Kimura S, et al. Autologous transplantation of the internal limiting membrane for refractory macular holes. Am J Ophthalmol 2014;157:861–869.
3. Wong D, Steel DH. Free ILM patch transplantation for recalcitrant macular holes; should we save some internal limiting membrane for later? Graefes Arch Clin Exp Ophthalmol 2016;254:2093–2094.
4. Park SW, Pak KY, Park KH, et al. Perfluoro-n-octane assisted free internal limiting membrane flap technique for recurrent macular hole. Retina 2015;35:2652–2656.
5. Grewal DS, Mahmoud TH. Autologous neurosensory retinal free flap for closure of refractory myopic macular holes. JAMA Ophthalmol 2016;134:229–230.