Adherent ocular bandage may help close, protect trabeculectomy wounds

An adherent ocular bandage may comfortably protect the limbal-conjunctival wound after fornix-based trabeculectomy, according to a study.

The study authors suggested using a polyethylene glycol-based hydrogel in combination with two 10-0 nylon sutures to seal the conjunctival-limbal incision. Daniel Calladine, MB BS, BMedSci, MRCOphth, first study author of the poster presented at the American Society of Cataract and Refractive Surgery meeting, told Ocular Surgery News that the ReSure Adherent Ocular Bandage (Ocular Therapeutix) is applied as a liquid and forms a gel in 30 seconds, while in situ on the ocular surface.

The bandage prevents bleb leaks in the early postoperative period, even when antimetabolites are used, and represents a viable alternative to more complicated suturing methods, Dr. Calladine said.

“Once the hydrogel sets, the resulting bandage is approximately 90% water, which allows oxygen to permeate through the gel, similar to a bandage contact lens. When applied, it molds around the sutures and the surface irregularities of the de-epithelialized or damaged conjunctival tissue,” Dr. Calladine said. “On the surface, it forms a smooth hydrated barrier that helps to prevent friction with the upper lid during blinking and improves comfort for patients.”

Because the bandage is extremely hydrophilic, Dr. Calladine and his colleagues hypothesize that it will absorb antibiotics such as fluoroquinolones from the tear film and help to concentrate them in the tissue surrounding the wound, thus providing an added level of protection.

“[The ReSure Adherent Ocular Bandage] is particularly advantageous to elderly patients, who often have thin and fragile conjunctivae that can be easily damaged during surgery or in whom it is difficult to place multiple purse string sutures,” Dr. Calladine said.

Methods, prior research

The prospective, consecutive study incorporated eight cases of trabeculectomy surgery performed by the same surgeon but covering a variety of patient demographics and techniques with or without anti-metabolites. In all cases, the incision was closed using two interrupted sutures with buried knots, and the wound was dried before application of the bandage.

“There is no substitute for good surgical technique, but the attractiveness of the hydrogel is its use as a welcome adjunct to a straightforward suturing technique that is both simple to perform and easy to reproduce with good outcomes,” Dr. Calladine said.

In a case-control study that was published in the Journal of Cataract and Refractive Surgery in 2010, Dr. Calladine examined use of the ReSure Adherent Ocular Bandage for clear corneal incisions following cataract surgery. The most significant findings were derived from anterior segment optical coherence tomography images, which demonstrated that the hydrogel molded to epithelial damage and then cleared gradually as the wound healed.

“After this experience, it seemed obvious to transfer this technique to trabeculectomy surgery,” Dr. Calladine said.

The hydrogel barrier covers and protects the conjunctiva from any unwanted shearing of the suture and is effective in cases requiring reoperation, in which inflamed or scarred conjunctiva is more prevalent.

Maximizing outcomes, study findings

There are two important techniques that maximize the hydrogel’s benefits, according to Dr. Calladine. First, surgeons should dry the wound and surrounding ocular tissue just prior to application. Dr. Calladine uses an absorbent, cellulose polyvinyl alcohol spear or sponge with his left hand just before applying the hydrogel with his right.

Second, surgeons should not to apply multiple hydrogel layers.

“Applying several layers does not make the bandage stronger, and the increased volume can result in foreign body sensation or become dislodged when the patient blinks. One smooth layer is enough,” Dr. Calladine said.

All eyes in the study experienced full wound coverage at 1 hour, with 75% maintaining full coverage on postop day 1. Gradual replacement of the hydrogel occurred over the 1 week of follow-up. On day 7, however, there were two cases of partial coverage, which was localized to the area surrounding the sutures and not the wound’s center.

None of the incisional wounds were leaking during suture removal on day 7, and all cases had a visible posterior bleb. The ocular bandage caused no added complications and helped to tamponade the anterior portion of the scleral flap and encouraged posterior drainage as well as bleb formation.

Dr. Calladine said he is investigating how hydrogels interact with healing corneal epithelial cells, as well as their potential to absorb and provide sustained release of topically applied ophthalmic medications.

“I believe in situ gel-forming hydrogels in certain disease states will replace cyanoacrylate glues and amniotic membrane grafts as the optimal treatment of choice,” he said. – by Michelle Pagnani

References:

• Calladine D, Ratnarajan G, McAllister J., New polyethylene glycol ‘hydrogel bandage’ technique to cover the conjunctival-limbal wound in fornix-based trabeculectomy surgery [published online ahead of print May 23, 2011]. Clin Exp Ophthalmol. doi: 10.1111/j.1442-9071.2011.02548.x.
• Calladine D, Ward M, Packard R. Adherent ocular bandage for clear corneal incisions used in cataract surgery. J Cataract Refract Surg. 2010;36(11):1839-1848.

• Daniel Calladine, MB BS, BMedSci, MRCOphth, can be reached at the Oxford Eye Department, John Radcliffe Hospital, Oxford, OX3 9DU, U.K.; email: drdancalladine@doctors.org.uk.
• Disclosure: Dr. Calladine has no relevant financial disclosures.