LAUSR

Dear Editor, I was recently challenged by a very daunting situation during a filtering glaucoma procedure I thought I should share with my colleagues. A 68-year-old male patient had previously undergone 25G pars plana vitrectomy with silicone oil tamponade and endolaser photocoagulation for a retinal detachment in his r igh t eye 4 years ago . Three years l a t e r, a f t e r phacoemulsification and intraocular lens implantation, he developed glaucoma. He was on maximal medical therapy and uncontrolled intraocular pressure. I thought the best option for him was a mitomycin-C trabeculectomy. During surgery, I noticed that the scleral flap was very thin but proceeded with the surgery. I placed two sutures with 10-0 nylon on a spatula needle on each corner of the flap and noticed a greater flow through the nasal aspect of the flap. I decided to place a third suture when a larger than usual hole developed and increased to a complete tear when tying the knot. Balanced salt solution (BSS) was flowing freely through the flap tear and the anterior chamber was flat. The placement of additional sutures was virtually impossible since that could create another tear. I thought about the amputation of the original flap and use a donor sclera to create a patch graft to replace it, but there was no tissue available in the operating room. As a last resource, I decided to try the application of cyanoacrylate glue. Using a polyvinyl acetal sponge to keep the flap surface dry, I placed a drop of n-butyl-2-cyanoacrylate adhesive on top of the flap with a 27G subcutaneous needle (Fig. 1). After a minute, the adhesive was allowed to polymerase with a drop of BSS, the flap was adhered to the bed, and a thin flow of BSS could be noticed. I sutured the conjunctival flap and refilled the anterior chamber with BSS. On the next day, intraocular pressure (IOP) was 7 mmHg and the anterior chamber was deep. Cyanoacrylate is a strong fast-acting biodegradable adhesive that polymerizes upon contact with tissues. It has been used for hemostasis, wound closure, hardware fixation, and application of skin grafts. In eye surgery, it has been used in a variety of different procedures, e.g., vitreoretinal surgery for retinal detachment, to stimulate adhesion of the elevated cuff of neurosensory retina surrounding a full-thickness macular hole, in the closure of corneal lacerations, blepharorrhaphy in patients with recalcitrant exposure keratopathy, and to attach eyelid skin grafts [1]. Recently, we described the use of cyanoacrylate in a patient with drainage device tube leak [2]. The cyanoacrylate adhesion to the sclera in this patient resulted from both mechanical interlocking and covalent chemical bonding. The low viscosity of the monomer allowed the surface to be moistened; undulations and imperfections of the wrinkled surface had been penetrated providing the basis for excellent mechanical interlocking when polymerization occurred. Indeed, the surface of the scleral flap had a very smooth appearance as seen with the surgical microscope. Although effective short-term biocompatibility has been previously demonstrated, we are unsure as to the long-term effect of cyanoacrylate glue on a subconjunctival space [3–5]. It is possible that, in time, it would promote fibrosis and scaring, ultimately leading to glaucoma bleb failure. Indeed, this was possibly the case since, on postoperative day 16, the filtration bleb started to decrease in size and IOP to elevate. Traverso’s maneuver and digital massage were unable to lower the IOP and the patient was started on topical hypotensive medications. At the last follow-up—6 weeks after the procedure—IOP was 20 mmHg on four medications, the bleb was flat, extended for less than one clock hour, and had moderate vascularity. In this patient, cyanoacrylate was used as a last resource in an emergency situation. Adhesion of the scleral flap with cyanoacrylate glue was achieved at least temporarily allowing for more adequate planning and intervention at a later time. * Niro Kasahara