Ophthalmic Surgery, Lasers and Imaging Retina

Clinical Science 

Comparison of Inverted ILM-Stuffing Technique and ILM Peeling Alone for Optic Disc Pit-Associated Maculopathy: Long-Term Results

Raghav Ravani, MD; Atul Kumar, MD; R. Karthikeya, MD; Pradeep Kumar, MS; Yogita Gupta, MBBS; Vinit Mutha, MD; Shilky Singh, MOptom

Abstract

BACKGROUND AND OBJECTIVE:

To evaluate long-term outcomes of inverted internal limiting membrane (ILM) stuffing into the optic disc pit for optic disc pit maculopathy (ODP-M) compared with vitrectomy with ILM peeling alone.

PATIENTS AND METHODS:

Twelve eyes of 12 patients who underwent vitrectomy for ODP-M and followed up more than 12 months were included. We retrospectively analyzed outcomes of inverted ILM flap stuffing into ODP (group 1, n = 6) with ILM peeling alone (group 2, n = 6).

RESULTS:

At 12 months, both groups showed significant improvement in best-corrected visual acuity and central macular thickness. On comparison, significantly faster resolution of maculoschisis was found in group 1 compared with group 2 (P = .012).

CONCLUSIONS:

Pars plana vitrectomy (PPV) with ILM peeling and PPV with inverted ILM stuffing are effective treatment modalities for ODP-M, with inverted ILM stuffing showing faster resolution of maculoschisis.

[Ophthalmic Surg Lasers Imaging Retina. 2018;49:e226–e232.]

Abstract

BACKGROUND AND OBJECTIVE:

To evaluate long-term outcomes of inverted internal limiting membrane (ILM) stuffing into the optic disc pit for optic disc pit maculopathy (ODP-M) compared with vitrectomy with ILM peeling alone.

PATIENTS AND METHODS:

Twelve eyes of 12 patients who underwent vitrectomy for ODP-M and followed up more than 12 months were included. We retrospectively analyzed outcomes of inverted ILM flap stuffing into ODP (group 1, n = 6) with ILM peeling alone (group 2, n = 6).

RESULTS:

At 12 months, both groups showed significant improvement in best-corrected visual acuity and central macular thickness. On comparison, significantly faster resolution of maculoschisis was found in group 1 compared with group 2 (P = .012).

CONCLUSIONS:

Pars plana vitrectomy (PPV) with ILM peeling and PPV with inverted ILM stuffing are effective treatment modalities for ODP-M, with inverted ILM stuffing showing faster resolution of maculoschisis.

[Ophthalmic Surg Lasers Imaging Retina. 2018;49:e226–e232.]

Introduction

Optic disc pit (ODP), first described by Wiethe in 1882,1 is a rare congenital anomaly characterized by excavation of the optic disc, mostly at its temporal margin.2 It is typically unilateral but may be bilateral in up to 15% of cases.2 Its reported incidence is about one in 10,000.3 Although an uncomplicated ODP usually does not affect vision, 25% to 75%4 of eyes develop ODP maculopathy (ODP-M), causing progressive visual loss. ODP-M consists of macular changes such as serous detachment, cystic degeneration, degenerative pigmentation, and macular schisis.5–8

Management options for ODP-M include laser photocoagulation of the pit margin, macular buckling, and pars plana vitrectomy (PPV) with or without internal limiting membrane (ILM) peeling. Sealing the ODP by injection of autologous platelets,9 transplantation of autologous sclera,10 and placing inverted ILM flaps11 over the disc pit have also been attempted, after which maculopathy may still reappear, leading to failure of these procedures.

Various attempts continue to refine surgery for ODP-M. The authors have previously reported successful outcomes with PPV with induction of posterior vitreous detachment (PVD) and ILM peeling without laser or gas tamponade in cases with ODP-M.12 In 2016, Nawrocki et al. described a novel surgical technique of stuffing the inverted ILM flap into the ODP and proposed that this would cause permanent closure of the pit and prevent subretinal and intraretinal fluid migration.13 The current study was done to compare the visual and anatomic outcomes of ILM peeling alone versus ILM peeling followed by stuffing of inverted ILM flap into ODP for cases of ODP-M.

Patients and Methods

This was a retrospective, single-center, comparative, interventional study that strictly adhered to the tenets of the Declaration of Helsinki. It was approved by the Institute ethics committee. Before the surgery, a written informed consent was obtained not only for the surgery but also for use of the data for future research studies.

We retrospectively reviewed the medical records of patients having ODP-M with or without neurosensory detachment (NSD) who underwent PPV with inverted flap with stuffing into the ODP between June 1, 2015, and July 31, 2016, and compared the results with that of six consecutive patients who underwent PPV with ILM peeling alone, before adoption of inverted ILM flap with stuffing technique, most of which were operated between January 1, 2015, and December 31, 2015, at our tertiary eye center. Inclusion criteria included all patients ages 18 years or older, presence of macular retinoschisis with or without NSD, reduced visual acuity (VA) (< 6/18), and follow-up of more than 12 months. Patients with preoperative VA better than 6/18 with no complaints and those with less than 12 months of follow-up postsurgery were excluded. The same inclusion and exclusion criteria were applied to both groups.

The details recorded from the case files included history and duration of symptoms, pre- and postoperative best-corrected VA (BCVA) on the logarithm of the minimum angle of resolution (logMAR) scale using the Early Treatment Diabetic Retinopathy Study chart, preoperative and 12-month postoperative central macular thickness (CMT) on optical coherence tomography (OCT), lens status, types of tamponade used, presence or absence of residual macular schisis, duration of resolution of schisis, and intraoperative and postoperative complications.

All patients underwent 23-gauge PPV by a single surgeon (AK) with triamcinolone acetonide-assisted induction of PVD and staining of ILM using brilliant blue G (ILM-Blue; DORC International, Zuidland, The Netherlands) for 2 minutes. Patients in group 2 underwent conventional peeling of ILM over the macula extending up to the arcades and temporal disc margin. In group 1, along with ILM peeling as done in group 2, a temporal optic disc edge-based ILM flap was raised and inverted over the optic disc to cover the optic pit. The ILM was stuffed into the optic pit using a diamond-dusted membrane scraper/ILM forceps (Figure 1). This step was performed with the help of visualization under an intraoperative OCT (iOCT) system (Rescan 700; Carl Zeiss Meditec, Jena, Germany). The redundant ILM was trimmed using a vitrectomy cutter. In both groups, surgery was concluded with fluid-air exchange and sulfur hexafluoride gas tamponade without laser photocoagulation around the temporal edge of the ODP. Both groups received similar postoperative care.

Intraoperative image (a) and schematic diagram (b) showing the technique of internal limiting membrane stuffing in group 1.

Figure 1.

Intraoperative image (a) and schematic diagram (b) showing the technique of internal limiting membrane stuffing in group 1.

The data were entered into an Excel spreadsheet (Microsoft, Redmond, WA). All statistical analyses were performed using SPSS for Windows version 17.0 (SPSS, Chicago, IL). Descriptive statistics were obtained. All data were presented as mean ± standard deviation. Calculated means in the two groups were compared using Mann-Whitney U test. To evaluate the surgical outcomes, Wilcoxon signed-rank test were performed. A P value of less than .05 was considered significant.

Results

Patient Population

Group 1: A total of six patients (three males, three females) with a mean age of 26.5 years ± 13.27 years (range: 18 years to 53 years) and a mean follow-up of 16 months (range: 15 months to 17 months) were included. Group 2: A total of six patients (two females, four males) with a mean age of 22.5 years ± 9.8 years (range: 13 years to 40 years) and mean a follow-up of 14 months (range: 12 months to 16 months) were included.

Clinical characteristics: On clinical examination, ODP-M with NSD was seen in all patients except patient No. 2 in group 1 and patient No. 5 in group 2, who presented with multilayered schisis without NSD. None of the patients had PVD or evidence of vitreomacular or vitreopapillary traction either clinically or on OCT.

Anatomical Results

Postoperatively, OCT revealed complete resolution of maculopathy (Figure 2) in all eyes except for one patient in group 2 who showed persisting NSD at 12-month follow-up (Figure 3). BCVA improved in both groups at 12-month follow-up (P = .012 in both groups). There was no significant difference in magnitude of improvement in the two groups (0.43 ± 0.23 logMAR units in the ILM-stuffing group and 0.49 ± 0.36 logMAR units in the ILM-peeling group, P = .6) (Table 1). However, the ILM-stuffing group showed significantly lower (P = .012) mean duration of resolution of maculoschisis in inner and outer layers and other macular changes (Table 2). CMT was noted to improve significantly from 585 μm ± 84.71 μm to 208.66 ± 43.95 μm in the ILM-stuffing group (P = .027) and from 562.83 μm ± 120.48 μm to 272.5 μm ± 128.4 μm in the ILM-peeling group (P = .0277). None of the eyes showed complications such as rise in intraocular pressure, hypotony, retinal breaks, or retinal detachment at 1-year follow-up.

Preoperative (a) and postoperative (b) optical coherence tomography scans of patient 1 of the internal limiting membrane (ILM)-stuffing group showing complete resolution of outer retinal schisis and neurosensory detachment following inverted ILM stuffing over the pit in group 1.

Figure 2.

Preoperative (a) and postoperative (b) optical coherence tomography scans of patient 1 of the internal limiting membrane (ILM)-stuffing group showing complete resolution of outer retinal schisis and neurosensory detachment following inverted ILM stuffing over the pit in group 1.

Preoperative (a) and postoperative (b) optical coherence tomography scan of a patient in group 2 showing a decrease but persistent neurosensory detachment at 12 months postsurgery with internal limiting membrane ILM peeling alone in group 2.

Figure 3.

Preoperative (a) and postoperative (b) optical coherence tomography scan of a patient in group 2 showing a decrease but persistent neurosensory detachment at 12 months postsurgery with internal limiting membrane ILM peeling alone in group 2.

One-Year Outcomes of BCVA in ILM-Peeling and ILM-Stuffing Groups

Table 1:

One-Year Outcomes of BCVA in ILM-Peeling and ILM-Stuffing Groups

Comparison of Observed Parameters in ILM-Peeling and ILM-Stuffing Groups

Table 2:

Comparison of Observed Parameters in ILM-Peeling and ILM-Stuffing Groups

Discussion

The optimal surgical management of ODP is controversial. In cases of ODP-M, a PPV is the standard of care.14 However, various surgical procedures have been described as adjuncts to vitrectomy, including barrage laser photocoagulation, air or gas tamponade, silicone oil tamponade, ILM peeling, draining the submacular fluid, removing glial tissue from the ODP, with no use of tamponading agent or laser,15 inversion of peeled ILM into the ODP,11 and inner retinal fenestration.16

ILM peeling is emerging as one of the most commonly used surgical techniques for ODP-M. It relieves the tangential and anteroposterior traction, which is believed to facilitate passage of fluid from the ODP into the macula. Our experiences with this technique have also shown favorable results.12 In a small case series of six patients, we could achieve good anatomical and functional outcomes in cases of ODP-M by performing PPV with PVD induction and ILM peeling, without use of any endotamponade or laser. Few researchers report recurrence of maculopathy at 12 months to 18 months after ILM peeling and inversion over ODP.13

Recently, the role of stuffing the ILM flap into the ODP is being explored. The proposed hypothesis for this is that it prevents subretinal and intraretinal passage of fluid permanently and more effectively than the technique of just peeling the ILM, which merely relieves tangential and anteroposterior traction. Nawrocki et al.13 reported good visual outcomes and complete resolution of subretinal fluid at 1-week follow-up in all three eyes that underwent ILM stuffing. They attributed their surgical success to a long-lasting positive therapeutic effect of ILM stuffing by preventing translaminar pressure differences and blocking flow of fluids.13 This is in coherence with the hypothesis postulated by Jain and Johnson17 that anatomical defects exist in cases of ODP either in the lamina cribrosa, the juxtapapillary sclera, or both, which create an abnormal linkage between the extraocular and intraocular spaces. Depending on the pressure differences, intraretinal and subretinal migration of fluid (vitreoretinal or cerebrospinal) may occur in cases of ODP-M.17

In our study, all eyes with ODP-M showed improvement in VA 1 year after surgery. The use of gas as endotamponade may help to keep the flap in place over the pit and prevent its slippage. Also, gas tamponade may help to keep the optic pit isolated away from the fluid currents and may help bring about faster resolution of the maculoschisis, avoiding the need for laser around the pit. Although the visual outcomes were similar with both techniques, the ILM stuffing technique showed faster resolution of maculoschisis than ILM peeling only. To our best knowledge, no study exists in literature comparing long-term outcomes of these two techniques for managing ODP-M.

In 2012, Shukla et al.18 performed PPV with ILM peeling, barrage laser, and gas tamponade in a study involving seven eyes and reported good surgical outcomes. However, they reported that four eyes developed full-thickness macular hole (FTMH) postoperatively, which they attributed to peeling over the thinned-out retina. In the current study, no eye developed FTMH postoperatively. The role of fovea-sparing ILM peeling19 and use of intraoperative OCT in ILM peeling for maculoschisis in myopic patients to avoid FTMH has been well-described.20 Our experience with iOCT-guided center-sparing ILM peeling for patients with myopia has shown favorable anatomical and functional outcomes without formation of macular hole.20 Thus, we integrated the use of iOCT with vitreous surgery in patients with ODP-M. It may be that assistance of iOCT for ILM peeling used in the current study that helped in avoiding peeling over thin cystic areas may have helped to prevent formation of FTMH in group 1. Also, the use of iOCT facilitated in exact localization of the ILM flap on ODP (Figure 4), which can be confirmed after fluid-air exchange to ensure proper coverage and absence of slippage.

Intraoperative optical coherence tomography image confirming proper placement of inverted internal limiting membrane (ILM) flap over the pit after ILM peeling with the ILM-stuffing technique.

Figure 4.

Intraoperative optical coherence tomography image confirming proper placement of inverted internal limiting membrane (ILM) flap over the pit after ILM peeling with the ILM-stuffing technique.

Our study with 12-month follow-up data of 12 patients adds to the current knowledge of the role of ILM stuffing into the ODP to achieve faster anatomical and visual outcomes. The study being nonrandomized, there is an inherent risk of bias. A prospective, randomized, comparative study with a larger sample size may be ideal. Although a relatively small sample size may be one of the limitations of the study, with incidence of ODP-M being low, a larger sample size is difficult. Also, use of electrophysiology such as multifocal electroretinography may be useful to determine and compare functional outcomes of the two procedures. Although stuffing of the flap into the optic pit involved minimal manipulation of the flap with soft instrument without manipulating the optic disc, the long-term effect on visual field or electrophysiology and conduction needs to be assessed. We believe that patients with chronic ODP-M, those with higher CMT leading to intraoperative difficulty in peeling the ILM and lower countertraction, presence of retinoschisis, and those with recurrence of maculopathy after PPV alone may benefit from the ILM-stuffing technique. However, further studies with a larger sample size supporting the same is required.

References

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One-Year Outcomes of BCVA in ILM-Peeling and ILM-Stuffing Groups

Improvement in BCVA (logMAR)ILM-Peeling Group (Six Eyes)ILM-Stuffing Group (Six Eyes)
Mean0.4330.493
Standard deviation0.230.36
Median0.410.36
Range0.17–0.870.13–1.12

Comparison of Observed Parameters in ILM-Peeling and ILM-Stuffing Groups

ParameterILM-Peeling Group (Six Eyes)ILM-Stuffing Group (Six Eyes)P Value
Mean age, years22.5 ± 9.8127.8 ± 14.41.62
Mean preoperative BCVA, logMAR units0.79 ± 0.240.76 ± 0.31.7
Mean postoperative BCVA, logMAR units0.36 ± 0.190.26 ± 0.11.39
Mean reduction in CMT, μm376.33 ± 121.22 (from 562.83 ± 120.48 to 272.5 ± 128.4, P = .0277)290.33 ± 82.21 (from 585 ± 84.71 to 208.66 ± 43.95, P = .0277).47
Mean duration of resolution of macular schisis, months6.08 ± 0.734.08 ± 1.11.012*
Improvement in BCVA at 1-year follow-up, logMAR0.43 ± 0.230.49 ± 0.36.6
Authors

From Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences (AIIMS), New Delhi, India.

The authors report no relevant financial disclosures.

Address correspondence to Raghav Ravani, MD, c/o Atul Kumar, MD, Room No. 485, 4th floor, Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India; email: raghavravani@yahoo.com.

Received: November 05, 2017
Accepted: April 10, 2018

10.3928/23258160-20181203-12

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