Study: Epiretinal membrane stripping is no benefit for idiopathic macular hole

Another study tried to assess benefits of ILM peeling in macular hole and other retinal conditions.

EDINBURGH, Scotland — Epiretinal membrane stripping in acute idiopathic macular holes confers no benefits nor causes an adverse effect on the rate of anatomical closure or postoperative vision, a study discussed here concluded. A separate study showed that selective peeling of the internal limiting membrane (ILM), however, might improve the success rate in macular hole surgery. In addition, ILM peeling was found to be useful in reducing metamorphopsia in cellophane maculopathy.

Epiretinal membrane stripping

The epiretinal membrane stripping investigation, presented here at the Club Jules Gonin meeting by Raymond R. Margherio, MD, was designed to evaluate the effect of epiretinal membrane peeling in patients undergoing pars plana vitrectomy for acute idiopathic macular holes. “Certainly, peeling of preretinal tissue, as far as surgery is concerned, is the most difficult, time consuming and stressful part of this operation,” Dr. Margherio said. “It can lead to the formation of retinal tears, hemorrhages, damaged photoreceptors, damage to Bruch’s membrane and retinal pigment epithelium [RPE] pigmentary changes.”

The retrospective study included two consecutive groups of patients operated on during a 3-year period and followed for at least 6 months. During this period, 107 eyes from 105 consecutive patients were operated on for acute idiopathic macular holes. The study was limited to patients with acute macular holes that were present for less than 1 year, in which all other chronic ocular diseases were absent and where adjuvants were not used.

All patients underwent pars plana vitrectomy with stripping of posterior cortical vitreous, fluid-gas exchange and postoperative positioning. One cohort had routine epiretinal membrane/ILM stripping. In the other cohort, there was no attempt to strip epiretinal tissue no matter what the clinical appearance of the macula was. The only statistically significant difference, according to Dr. Margherio, was that in the non-peeling group there was a slightly higher incidence of type 2 macular holes.

The study concluded that there was no significant difference between the cohorts in anatomical closure rates or visual results. “We could see a statistically significant improvement between the preoperative and postoperative visual acuity overall and in each cohort,” Dr. Margherio said. The mean preoperative visual acuity in each group was 20/125. Mean postoperative visual acuity was 20/56 in eyes where membrane stripping was done, and 20/43 in eyes without membrane stripping. According to Dr. Margherio, 64% of the stripped membrane cohort achieved 20/50 or better visual acuity compared with 85% of the group that did not have epiretinal membrane stripping. “However, when we did a subgroup analysis, remembering that we had more stage 2 holes in the cohort without stripping, this difference was not significant.”

Complications included retinal detachment, which occurred in 6% of all patients, and an increase in intraocular pressure in about 23%. There was no significant difference in complications between the two cohorts.

“When we tried to determine a difference between years 1, 2 and 3. There was a statistically significant improvement in our anatomical closure of macular holes between year 1 and year 3, where we went from 80% to better than 96%,” Dr. Margherio said. “There was no statistically significant difference between the two cohorts, however, as years progressed. Epiretinal membrane stripping showed no beneficial or adverse effects to preretinal tissue dissection on the rate of anatomical closure or postoperative visual improvement in acute idiopathic macular holes.”

ILM peeling

Peeling of the ILM is thought to play a role in the pathogenesis of macular holes, according to this study’s presenter and author Klaus Lucke, MD. “It is our feeling that macular holes have a much better release of foveal traction and that ILM must play a vital role in the pathogenesis of macular holes, whether in the formation or the stabilization of the macular hole, we are not sure,” Dr. Lucke said. “In cellophane maculopathy … there was little effect on visual acuity.”

Patients with diabetic macular edema had good results following ILM peeling; however, there were a few unexplained losses, according to Dr. Lucke. “We are not sure why edema should be reduced after ILM removal,” he said. “We think maybe we removed a diffusion barrier in those cases.”

Initial reports, according to Dr. Lucke, indicate that peeling of the ILM is helpful in closing macular holes. Changes in the ILM also may play a role in the development or maintenance of cystoid macular edema (CME) in various macular conditions and can cause metamorphopsia in cellophane maculopathy. Since safe techniques are available and allow for the removal of ILM without significant injury to the underlying retina, the physicians investigated whether removal of the ILM could be helpful in macular holes and other macular disorders.

In the study, after victrectomy, vitreous detachment and epiretinal membrane removal, macular ILM was selectively removed in eyes undergoing vitrectomy in 28 patients with macular holes, diabetic macular edema in nine patients, different types of CME in five and cellophane maculopathy in six.

Macular holes were successfully closed in all patients but one, according to Dr. Lucke. The remaining case had a large rigid macular hole for 3 years. “What we observed was that ILM was adherent to the edge of the macular holes,” Dr. Lucke said. “When we freed the holes of the ILM, the shape of the hole changed dramatically. The edge wasn’t curled in anymore and they were much easier to close.” Dr. Lucke mentioned that although his results were not statistically significant, it is a big advance in the success rate.

In diabetic eyes, the edema noticeably dropped postoperatively both funduscopically and by fluorescein angiography. In some of these cases, edema persisted in areas of the retina where the lamina had not been removed. “We were wondering if removing the ILM would do something positive for diabetic macular edema,” Dr. Lucke said. “The visual acuity was down to 0.1. One month postoperatively, the edema had subsided significantly and the visual acuity had gone up slightly. We are thinking that maybe we removed a diffusion barrier in those cases.” Dr. Lucke said this was rare. In most cases with preop massive edema, it resolved well but the visual acuity did not improve.

Three of five CME patients had subjective and objective signs of improvement. Two remained unchanged. For cellophane maculopathy, visual acuity was not affected dramatically by ILM removal; however, there were no negative results. Metamorphopsia improved in all eyes with cellophane maculopathy.

“It [ILM removal] is technically difficult,” Dr. Lucke said. “There is definitely a learning curve to this.”

For Your Information:

Raymond R. Margherio, MD, can be reached at 632 William Beaumont Medical Building, 3535 W. 13 Mile Road, Royal Oak, MI 48073 U.S.A.; +(001) 248-288-2280; fax: +(001) 248-288-5644. Dr. Margherio has no direct financial interest in any products mentioned in this article, nor is he a paid consultant for any companies mentioned.

Prof. Dr. med. Klaus Lucke, can be reached at Tagesklinik Universitätsallee, Universitätsallee 3, D-28359 Bremen, Germany; +(49) 421-2012-80; fax: +(49) 421-2012-851; e-mail: TKU_BREMEN@Compuserve.com. Dr. Lucke has no direct interest in any products mentioned in this article, nor is he a paid consultant for any companies mentioned.