Study shows not removing viscoelastic after trabeculectomy lowers postop complications

Viscoelastic’s maintenance of the anterior chamber following trabeculectomy and phacotrabeculectomy leads to improved long-term results.

BOSTON — The intraoperative application of Healon (sodium hyaluronate; Pharmacia Corporation) in trabeculectomy and phacotrabeculectomy without removal of the viscoelastic at the end of surgery lowers the risk of postoperative complications significantly, thus improving the long-term results. This operation also seems to compare favorably with non-filtering procedures, according to one study.

Corina Buhler, MD, presented these findings during the American Society of Cataract and Refractive Surgery meeting held here. “The advantage of this technique is the maintenance of the anterior chamber during and after surgery, the avoidance of hemorrhages and better bleb formation due to the viscoelastic being washed out from the anterior chamber,” Dr. Buhler said.

In the prospective study, 114 consecutive eyes were operated on. Trabeculectomy was performed on 40 eyes, and trabeculectomy combined with phacoemulsification and IOL implantation were performed on 74 eyes. The average age of the patients was 70 years. All surgeries involved in the study were performed between August 1998 and August 1999.

Limiting postop complications

While trabeculectomy has proven to be an effective procedure, “the results of the operation may be reduced by early postoperative complications, which are mostly a result of bulbar hypotony,” Dr. Buhler said. “I found that in some data and literature, and especially in phacotrabeculectomy, there is a very high incidence in postoperative complications. These complications may lead to bleb failure and, therefore, to bad long-term results.

“We expected the use of viscoelastic substances, intracameral during glaucoma filtering surgery to reduce the postoperative complication rate,” Dr. Buhler said.

In the phacotrabeculectomy group, Healon was injected into the anterior chamber with the first entry into the anterior chamber. Phacoemulsification and IOL implantation were performed after that. After the IOL implantation, Healon was applied again into the anterior chamber. Then the trabeculectomy was continued.

Dr. Buhler said postoperative complications were limited to blood remnants in the anterior chamber in two eyes, which is equal to 5% in group 1, and three eyes, or 4%, in group 2. “It’s just the small blood clots in the anterior chamber. In the phacotrabeculectomy group, the results were about the same. The only difference we had was fibrinous exudation in 9.5% of the patients, which dissolved spontaneously in the first few postoperative days.”

Fibrinous exudation

Dr. Buhler attributed the fibrinous exudation in the phacotrabeculectomy group to the phacoemulsification performed. She said there was no fibrinous exudation in the trabeculectomy group. She also said that these were straightforward cases in which she had no reason to suspect that there was a breakdown of the blood-aqueous barrier.

The first assessment was performed after 4 hours. Minimal follow-up time was 3 months. “At 4 hours postop, the intraocular pressure [IOP] was lower than 10 mm Hg. So the IOP didn’t rise after surgery as feared,” she said.

“After 3 months, the IOP was 16.4 mm Hg in the trabeculectomy group and 15.6 mm Hg in the phacotrabeculectomy group. Before the operation, all patients needed local or systemic antiglaucomatous medication. After the operation, in the trabeculectomy group, 30% of the patients still needed an average of 1.5 medications. In the phacotrabeculectomy group, 15% of the patients needed an average of 1.2 medications,” she said.

Dr. Buhler said, “We can say that the intraoperative use of Healon in trabeculectomy and phacotrabeculectomy, especially without removing the substance at the end of surgery, does reduce the early complication rate without leading to postoperative IOP spikes,” Dr. Buhler said. “So minimizing the complication rate postoperatively may improve the long-term results, as well.”

For Your Information:

Corina Buhler, MD, can be reached at Augenklinik der Bundesknappschaft, An der Klinik 10, 66280 Sulzbach, Germany; +(49) 68-97-5741119; fax: +(49) 68-97-5742139. Dr. Buhler has no direct financial interest in any of the products mentioned in this article, nor is she a paid consultant for any companies mentioned.

Pharmacia Corporation can be reached at 100 Route 206 N., Peapack, NJ 07977 U.S.A.; +(1) 908-901-8000; fax: +(1) 908-901-8379.