Phacotrabeculectomy: One site or two? It depends

Key Points

Fort Lauderdale, FL-A prospective, randomized comparison of one-site versus two-site phacotrabeculectomy found no statistically significant difference in IOP at 24 months. Surgical time, however, was almost 10 minutes longer for the two-site procedure.

In another key finding, endothelial cell counts were statistically significantly lower at 3 and 12 months in the eyes that had undergone two-site surgery, but the difference was no longer significant at 24 months, said Yvonne M. Buys, MD, FRCSC, at the Association for Research in Vision and Ophthalmology annual meeting.

"At present, I favor one-site surgery because of the findings of our study," said Dr. Buys, associate professor, department of ophthalmology, University of Toronto, Toronto. "The only reason I would do a two-site procedure is if it weren't ergonomically comfortable to do the phaco from the same site as the trabeculectomy, which can sometimes happen."

No significant differences in mean postoperative IOP were found when results were compared for patients whose primary indication for surgery was glaucoma or among those whose main indication was cataract.

Eighty patients were enrolled in the study. One patient withdrew consent prior to surgery, leaving 79 who were randomly assigned to one-site (n = 39) or two-site (n = 40) phacotrabeculectomy. The mean age was 69.5 years for patients undergoing one-site surgery and 72.3 years for those having two-site surgery. Both groups included more women than men, and at least 50% of each group was Caucasian. The most common form of glaucoma in both groups was primary open-angle glaucoma.

Dr. Buys performed all of the operations following a standardized surgical procedure. After administration of anesthetic, a 7-0 polyglactin 910 corneal traction suture was placed 1 mm in the clear cornea at 12:00. A fornix-based conjunctival flap was dissected for one-site cases, and a limbus-based conjunctival flap was used in two-site cases. The technique also varied when a 3.2-mm keratome was used to enter the anterior chamber beneath the scleral flap for one-site surgery and a clear corneal temporal incision for two-site surgery. The scleral flap was closed with two 10-0 nylon sutures in one-site surgery and three 10-0 nylon sutures in two-site surgery. In addition, one 10-0 nylon suture was placed through the temporal clear cornea incision in two-site surgery.

The postoperative data collected for analysis included complications and suture lysis. Visual acuity, IOP, and glaucoma medications were recorded at 3, 6, 12, and 24 months, and endothelial cells counts were taken at baseline and 3, 12, and 24 months.

Intraoperatively, no statistically significant differences were found between the groups for pupil manipulation or phacoemulsification parameters. Three intraoperative complications occurred in the one-site group, including a partial scleral flap dehiscence, a partial zonular rupture managed with a capsular tension ring, and a capsular rupture in which the posterior chamber IOL was fixated. Two intraoperative complications were seen in the two-site group: a conjunctival flap tear to the limbus and a conjunctival buttonhole.

The comparison of operative times yielded one of the study's most important findings: One-site surgery required significantly less time than two-site surgery (39.2 ± 6.4 minutes versus 48.1 ± 7.8 minutes, respectively, p < 0.01).

Postoperatively, suture lysis was necessary for 11 patients in the one-site group and 14 in the two-site group. One patient in the two-site group underwent a bleb needling procedure, and four from the one-site group underwent a YAG capsulotomy.