Securing success in phaco-trabeculectomy

October 1, 2008

Dr James Tsai outlines key points to ensure a good outcome.

Key Points

Cataract and glaucoma are common ophthalmic conditions seen in older age individuals. It therefore stands to reason that, as their incidences both increase with age, the two will occur simultaneously in many patients. The surgeon therefore has the decision of whether to perform the procedures in combination or sequentially.

Combination vs. separate surgeries

Notwithstanding this, combined surgery is not without its complications. Although it is more convenient for the patient and it may reduce the likelihood of postoperative IOP spikes than when cataract surgery is performed alone,3 combined surgery does have the potential to cause more intraoperative and postoperative complications than when either procedure is performed in isolation. For example, trabeculectomy has been known to induce the onset of cataract, whilst cataract surgery may cause bleb failure. From a patient's standpoint, combination surgery means a significant delay in visual rehabilitation. Hence, some surgeons still favour separate procedures.

James C. Tsai, MD, Professor and Chairman of Ophthalmology at Yale University School of Medicine, New Haven, Connecticut, US advocates the combination of phacoemulsification and trabeculectomy in specific patients, and believes that several modifications can be made in order to improve the overall outcome of phaco-trabeculectomy.

"In this day and age, there are many choices available to surgeons performing combined cataract and glaucoma surgery; for example, combined phaco and non-penetrating glaucoma surgery. However, I still believe that phaco-trabeculectomy offers excellent surgical outcomes and allows us to sustain long-term IOP control following surgery," said Dr Tsai, speaking at this year's World Ophthalmology Congress in Hong Kong.

Take simple steps to ensure success

"We're all aware of the risks of filtering surgery, including late-onset bleb leaks and anterior chamber shallowing in the early postoperative course, but I have incorporated some modifications which allow me to maximize the surgical outcome and minimize complications," he added.

Some of these modifications include the employment of topical and/or subconjunctival anaesthesia. "I believe that traditional retrobulbar or peribulbar anaesthesia poses a risk of haemorrhage following injection as well as a risk of transient no light perception vision in patients who have very precarious optic nerves," Dr Tsai warned.

He also supports the use of intraoperative viscoelastics to minimize the risk of hypotony.

In order to secure a diffuse, non-leaking filtering bleb, Dr Tsai uses a fornix-based conjunctival flap, "But I do make a modification to the technique, as I leave a 1 to 1.5 mm edge, or skirt, at the limbus so that, at the end of the procedure, I can perform a running conjunctival closure. I believe this gives enhanced filtering blebs and less risk of wound leak," he advised.

Dr Tsai also administers low dose MMC, usually at 0.2 to 0.3 mg/ml for two minutes, and employs releasable sutures, which allow him to control IOP in the immediate postoperative period. To ensure wound stability, Dr Tsai interlocks every second or third loop when making the running closure.