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At Issue: Peeling the internal limiting membrane during macular hole surgery
At Issue posed the following question to a panel of experts: "During macular hole surgery, do you peel the internal membrane, or not, and why?"
Peel in all stage III and IV cases
Tetsuo Hida, MD: I perform internal limiting membrane (ILM) peeling in all stage III and stage IV cases. In stage II cases, it depends. After all, there is quite a range in the clinical characteristics of macular holes diagnosed as being stage II. I do end up peeling the ILM when stage II holes appear close to stage III, and when it seems that a long period of time has elapsed since becoming a stage II hole.
I believe that the ILM itself does not participate in the initial formation of macular holes. Rather, I think that secondary changes (probably related to glial cells) are induced by longstanding posterior hyaloid traction, allowing the ILM to help in maintaining a macular hole once it has opened. Without a doubt, peeling of the ILM increases the surgical success rate of hole closure, and I have not experienced any clinically obvious complications due to this procedure. On the other hand, I do not believe that ILM peeling has absolutely no effect on retinal function. Furthermore, since the success rate of surgery was originally quite high without ILM peeling, clearly not all cases require it.
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Aggressive peeling lessens prolonged face-down positioning
Fadi Phillip Nasrallah, MD: A determining factor in macular hole surgery is the release of all traction on and around the hole whether anteroposterior or tangential. This means aggressive peeling of all membranes including the ILM. It seems to lessen the need for prolonged face-down positioning. This impression is supported by the findings of Park et al published in the July 1999 issue of Ophthalmology. The authors found that peeling the ILM not only compared favorably with conventional surgery as far as vision and anatomical success were concerned but also allowed for only 4 days of face-down positioning.
In my opinion aggressive peeling of all membranes on and around the hole, including the ILM, decreases the need for prolonged positioning and has helped me operate successfully on patients less able to comply with the prolonged face-down positioning. This maneuver prolongs the surgical time but does not seem to be associated with more complications. In compliant patients, rigorous positioning without ILM peeling remains a viable alternative.
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Remove ILM whenever possible
Theo Seiler, MD, PhD: There is clinical and histologic evidence that macular holes are a condition that originates from a pathologic activity in the ILM, the interface of retina and vitreous.
Recent publications compared the results of macular hole surgery with and without ILM-peeling. Although the results are based on retrospective studies or a meta-analysis, it is obvious that ILM-peeling significantly improves visual and anatomic success in all stages of macular holes and prevents reopening.
In the past, we performed vitrectomy only in cases where it was too difficult to remove the ILM with regard to complications. Based on the results presented, however, we try now to remove the ILM in any case possible.
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References:
- Brooks HL. Macular hole surgery with and without internal limiting membrane peeling. Ophthalmology 2000;107:1939-1947.
- Mester V, Kuhn F. Internal limiting membrane removal in the management of full thickness macular holes. Am J Ophthalmol. 2000;129:769-777.
Not yet settled
Louis D. Nichamin, MD: This question should be considered debatable and as yet not concretely answered. Like all vitreoretinal surgeons, I attempt to completely remove all abnormal premacular fibrosis and epiretinal tissue to relieve tangential traction on the fovea. In some cases the ILM is inadvertently removed with this tissue, but I do not attempt to specifically incise and remove the ILM. In several cases where this was attempted, modest surface bleeding was noted, and I could appreciate no improvement, although my particular series of cases are small in number. Clearly, some surgeons do feel that this is important. In a discussion of this subject, however, Dr. Ray Margherio points out that this topic is not yet settled.
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References:
- Margherio RR. Discussion by Raymond R. Margherio, MD. Ophthalmology 2000;107:1948-1949.
Stain, peel and use forceps
Jose Mª Ruiz-Moreno MD, and Jorge L. Alio, MD: In 1988, pre-macular vitreous tangential traction at the foveal level was established to be the main factor responsible for macular hole pathogenesis.
Elimination of the posterior cortical vitreous together with peeling of the posterior hyaloid membrane released this traction and allowed for complete closure of macular holes in 58% of cases.
Furthermore, elimination of the posterior hyaloid membrane with careful peeling of the epiretinal membranes at the macular area and use of C3F8 as a tamponade with proper postoperative positioning allows for closure of macular holes in 70 to 80% of holes.
Eliminating the ILM allows closure of macular holes in 90% of the cases and also decreases postoperative positioning time.
This operative technique is very delicate and requires an expert surgeon. In spite of this, different complications could occur, either intraoperatively as retinal breaks during elevation of ILM due to retinal incarceration in the silicone canula, or postoperatively as hyphema from small vessels injured at the time of initial flap creation. Also, phototoxicity due to prolonged surgical time and central field defects can occur postoperatively.
Recent studies showed that the same results could be obtained with or without peeling the ILM and that macular hole closure is possible in more than 90% of cases with both techniques.
At this moment we are following these techniques in all macular hole cases. We peel the ILM after staining with indocyanin green and complete the maculorrhexis using forceps. This has helped us to decrease postoperative positioning time for our patients to 7 days.
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Make at least one attempt to peel
Michael P. Teske, MD: Vitreoretinal surgery is successful in anatomically closing macular holes in better than 90% of eyes. Many vitreoretinal surgeons currently advocate peeling the internal membrane in all cases to improve the success rate. As is the case with the use of tissue “glues” or adjuvants, this remains unproven and an area of controversy.
The rationale for ILM peeling is that it may remove centripetal forces and/or create a stimulation and redirection of gliosis to help ensure hole closure. Perhaps the greatest benefit of ILM peeling is that there is some anecdotal evidence that it may decrease the importance of lengthy gas tamponade and face-down positioning for our patients.
My personal approach in macular hole surgery is to always make at least one attempt to elevate and peel the ILM once I am sure that all hyaloid tissue has been removed. I rarely make more than one attempt at peeling, to avoid undue trauma to the inner retinal tissue. My only exception to this is in larger holes, re-operations or post-traumatic macular holes.
There is definitely a technical learning curve involved in ILM peeling. I prefer to use a barbed MVR blade to initiate my peel (although I have used the Tano diamond-dusted membrane scraper with equal success), and then I switch to a vitreoretinal pick once I have established the proper plane. Finally the ILM is peeled with an intraocular forceps in a “maculorrhexis-like” fashion. I strive to remove ILM for at least 1,000 µm from the edge of the hole.
While I have not been able to demonstrate a clear statistical benefit of ILM peeling in my practice, I do believe that it may allow for less postoperative face-down positioning. In cases where ILM peeling is successful and complete, I now position my patients for only 5 days as opposed to 10 days without ILM removal.
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Important in treating some macular holes
George A. Williams, MD: With their seminal report in 1991, Kelly and Wendel opened a new era in macular surgery. Since then, investigators worldwide have confirmed the benefits of vitrectomy surgery for treatment of macular holes.
Anatomic closure has been correlated with multiple factors including preoperative duration of the hole, use of adjuvants, duration and type of vitreous tamponade, postoperative face-down positioning and intraoperative ILM dissection. ILM dissection appears to somehow enhance the gliotic response necessary for macular hole closure. The potential benefits of ILM dissection include a higher anatomic success rate and less stringent face-down positioning. Potential adverse sequelae of ILM dissection include intraoperative complications such as iatrogenic retinal damage, light toxicity and increased operating time.
Only a prospective randomized trial will conclusively establish the role of ILM dissection in macular hole surgery. However, such a trial is unlikely to occur because of the large number of patients necessary to show a clinically significant increase in either the anatomic or visual success obtainable without ILM dissection.
Despite this uncertainty, I believe ILM dissection does play an important role in the treatment of select macular holes, but is not necessary in all macular holes. I do not attempt to dissect the ILM in stage 2 holes and recent onset (less than 6 months) stage 3 holes because of the high success rates obtainable without dissection. I find ILM dissection helpful in chronic holes with known duration of 1 year or more. Large holes (more than 500 µm), traumatic holes and holes with an obvious epiretinal membrane or a “tight glistening” appearance to the inner retinal surface seems to benefit from ILM dissection. Finally, I will attempt ILM dissection in all patients unable or unwilling to position face down for a minimum of 1 week.
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Always attempt to remove during macular hole surgery
Prof. Ugo Menchini: I always try to remove the ILM during macular hole surgery. Sometimes, I use a scleral lance knife or a needle with a bended tip and an Eckardt forceps. Indocyanine green can be useful to stain the ILM when you peel it.
It's my personal opinion based on my surgical experience and on optical coherence tomography findings that the ILM plays a key role in the second phase of macular hole formation. Optical coherence tomography has recently shown that in most cases the formation of a macular hole is preceded by anteroposterior traction due to perimacular vitreous detachment that results in foveal traction. The early stage often consists of a foveal pseudocyst caused by the anteroposterior vitreous traction: publications based on optical coherence tomography have demonstrated that the pseudocyst can collapse spontaneously if complete vitreous detachment occurs, but it can progress to a partial- or full-thickness macular hole in some cases. I believe that after the macular hole has occurred, tangential traction resulting from ILM contraction may lead to hole enlargement. So I recommend ILM removal during macular hole surgery.
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