Ocular sealant proves effective for routine, unexpected cases

Take-home message: In this physician perspective, Robert J. Noecker, MD, MBA, describes the results he has experienced since he has begun applying an ocular sealant as the last step of every filtering procedure.

By Robert J. Noecker, MD, MBA, Special to Ophthalmology Times

Fairfield, CT-Wound leakage following trabeculectomy is not an infrequent occurrence and is a potential cause of complications-such as hypotony, flat anterior chamber choroidals and endophthalmitis, if not trabeculectomy failure.¹

Most studies consider leakage to occur in greater than 10% of fornix based surgeries.²

Though improved methods of wound closure can certainly decrease the probability for leakage, it is not possible to eliminate it completely.³

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A sealant for clear-corneal incisions following cataract surgery has been approved by the FDA, however, and has been useful for other ocular applications.

Sealant versus glue

Glues-such as fibrin glue and cyanoacrylate-are familiar to most ophthalmologists and used in appropriate situations to hold tissues together. Sealants, on the other hand, do not have the strength to hold tissue together, but rather act to plug defects or openings in tissue, preventing the passage of fluid.

Next: Good flow vs. bad flow

One sealant (ReSure Sealant, Ocular Therapeutix) is a hydrogel formed in situ. Polyethylene glycol is mixed with trilysine amine to create a polymeric crosslink. It is applied while still in a liquid state and specifically adheres to de-epithelialized tissue on the eye. It then sloughs off as underlying epithelium grows. This material was adapted from neurosurgery applications and has a proven track record for safety and efficacy.

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The sealant is a good preventative measure, as well as a lifesaver, for many unexpected situations, he noted.

Good flow versus bad flow

The goal with trabeculectomy (shunt surgery) is to get aqueous to flow out of the eye and into the subconjunctival space, thus lowering pressure.

However, unexpected leaks exaggerate flow causing serious complications. The goal is to keep IOP in a reasonable range-usually double digits-in the early postoperative period. This way, the eye functions normally, the patient sees well, and postoperative management is straightforward.

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Unfortunately, even the best glaucoma surgeons get leaks with a certain frequency. Sometimes a patient’s tissue shreds during suturing, making the surgeon alert to issues. Other times, a case seems to have finished very well, but every time the patient blinks there is a miniscule gap between sutures that leaks.

I have begun applying this sealant as the last step of every filtering procedure. Instead of creating a long-running suture, I most often put in one interrupted suture to secure the conjunctiva back together. I then mix the sealant and apply it to the patient’s eye after the surface is dried. It is ideal for glaucoma surgeries because the sealant automatically migrates to areas that do not have the epithelium attached, even if you cannot visualize the hole.

Next: Case series

Using the sealant has cut back suturing time by 5 minutes. The sealant naturally sloughs off in a day or two, but if a bandage contact lens (BCL) is used, it will last for a week or more.

One caveat is that the eye must be dry for the sealant to adhere. In many cases, aqueous is not actively flowing from the eye so the sealant can be applied without worry. In other cases, it may be necessary to drop IOP a bit or inject a small amount of viscoelastic into the eye to stop the flow of aqueous.

Case series

To evaluate the efficiency of the sealant as an adjunct to suture closure of the conjunctiva in glaucoma filtering surgery, 32 consecutive cases were compared in which the sealant was used to 30 prior consecutive cases in which sutures were used alone. All cases underwent a fornix-based approach.

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At the end of each case, two wing-sutures were placed at either end of the conjunctival flap. Care was taken to dry the intended area thoroughly with a Weck cell sponge. This removed any residual moisture that may have interfered with proper sealing, and also roughened up the epithelial layer overlying the conjunctival edge and cornea to facilitate proper adherence of the sealant. The two components of the sealant are mixed for about 5 seconds, and then the sealant is applied to the desired area within 10 seconds.

Upon evaluation, there were no cases of early postoperative wound leak in the sealant group and two cases of leak in the group with sutures alone. The leaks were stopped with conservative measures with BCL and resolved by the first week postoperatively.

Next: Concluding thoughts

In addition, the sealant group tended to have less discomfort and pain postoperatively, with six patients reporting symptoms in the sealant group and 24 patients reporting symptoms in the sutures-only group. Hydrogel materials have long been used in soft contact lenses, and it is likely the sealant acts in a similar way to provide additional comfort. There was no significant difference in IOP at 3 months between the groups.

References

• Van Buskirk EM. Five-year follow-up of the Fluorouracil Filtering Surgery Study. Am J Ophthalmol. 1996;122:751-752.

• Kirk TQ, Condon GP. Modified Wise closure of the conjunctival fornix-based trabeculectomy flap. J Cataract Refract Surg. 2014;40:349-353.

• Solus JF, Jampel HD, Tracey PA, et al. Comparison of limbus-based and fornix-based trabeculectomy: success, bleb-related complications, and bleb morphology. Ophthalmology. 2012;119:703-711.

Robert J. Noecker, MD, MBA

E: noeckerrj@gmail.com

Dr. Noecker is in practice with Ophthalmic Consultants of Connecticut, Fairfield, CT, and is assistant clinical professor, Yale University School of Medicine, New Haven, CT.

Surgical experience with a versatile tool

The most common use of the sealant for Robert J. Noecker, MD, MBA, is in conjunction with sutures during routine trabeculectomies or mini-shunt (EX-PRESS, Alcon Laboratories) filtering surgeries. However, he said it is helpful in a variety of situations: