December 2009

 

GLAUCOMA

 

Combined cataract, glaucoma procedures given a boost


by Rich Daly EyeWorld Contributing Editor

   

Study supports the safety and efficacy of a combined cataract and glaucoma procedure—counter to previous studies

Illustration of Ex-PRESS miniature glaucoma shunt insertion.

Source: Optonol Ltd.

The use of combined cataract and glaucoma shunt surgery may get a boost from a recent large-scale study comparing the outcomes of one such approach to the efficacy of a stand-alone procedure.

A large-scale evaluation of both the placement of an Ex-PRESS (Optonol, Kansas City, Kan.) miniature glaucoma device under a partial-thickness scleral flap as a single procedure and combined with phacoemulsification cataract surgery found solid clinical outcomes three years post-op. Patients undergoing the combined procedure had better overall results.

“The findings of this study support the safety and efficacy of the combined procedures that can save patients from having two separate procedures instead of one,” said Elie Dahan, M.D., professor of ophthalmology, University of the Witwatersrand, Johannesburg, South Africa.

The study, titled “Ex-PRESS Miniature Glaucoma Device Implanted Under a Scleral Flap Alone or Combined With Phacoemulsification Cataract Surgery,” was published online in February 2009 in the Journal of Glaucoma.

The comparative consecutive case series of 345 eyes included 231 eyes treated with the Ex-PRESS implant alone and 114 eyes treated with both the Ex-PRESS implant and phacoemulsification. The study, by Elliott Kanner, M.D., Ph.D., assistant professor of ophthalmology, University of Tennessee Health Science Center, Memphis, Tenn., and colleagues, found that the post-op IOP and number of glaucoma medications were “significantly lowered” in both groups, compared to baseline. Additionally, Dr. Kanner and colleagues found that three years post-op the surgical success was 94.8% for the stand-alone procedure and 95.6% in the combined group.

Those findings are important because safety and efficacy concerns have led many surgeons to hesitate in choosing combined procedures over separate procedures, said Dr. Dahan, who has implanted over 400 such devices under a scleral flap.

Thomas K. Mundorf, M.D., Charlotte, N.C, agreed that the study indicated that the combined approach would work in a similar manner to efficacy found in combined trabeculectomy and phacoemulsification surgeries. Another highlight of the study for Dr. Mundorf was the low erosion rate (0.3%), which was rarer than erosion found in previous studies of shunt implants. The authors credited the lower rates of erosion, hypotony, and other complications than the rates in previous combination studies to their placement of the device under a partial thickness scleral flap. The efficacy of that approach was supported by Iqbal (Ike) K. Ahmed, M.D, assistant professor, University of Toronto, Toronto, and clinical assistant professor, University of Utah, Salt Lake City. Dr. Ahmed, like the study authors and other surgeons, has found that placing the Ex-PRESS under a scleral flap, rather than under conjunctiva, results in lower complication rates and better outcomes.

Challenging previous studies

Another highlight of the study is its difference from some previous studies of more limited size and duration. Dr. Dahan said the study by Dr. Kanner and colleagues is important because it found equal success with both stand-alone shunt procedures and combined procedures, which differs from some previous reports where the outcomes favored separate glaucoma and cataract procedures.

Michèle Luce Detry-Morel, M.D., St. Luc University Hospital, Université Catholique de Louvain, Brussels, noted in a 1998 literature review that compared to cataract extraction alone, the combined procedures offer better protection against the risk of early post-op IOP increase. However, long-term intraocular pressure control was not as predictable with combined surgery as when the surgery was done in two stages. He also noted that combined operations tended to have a larger post-op rate of complications than cataract extraction alone.

Dr. Kanner and colleagues found similar types of complications in both the combined and stand-alone groups, while the rates varied. For instance, surgical failure due to increased IOP occurred in 3.4% of stand-alone procedure eyes and in 4.4% of combined procedure eyes. Bleb leaks occurred in 4.4% of combined procedure eyes and in 5.2% of filter-only recipient eyes. The authors also found the need for glaucoma medications dropped sharply in both groups of patients—even three years post-op—while the combined group required slightly fewer glaucoma medications than filter-only eyes.

Suggested pearls

The good combined procedure outcomes were credited to several factors. In addition to the benefits of placing the shunt under a partial-thickness scleral flap, the authors also credited the positive results to their use of laser suture lysis and the design of the device, which likely provides resistance to aqueous flow.

Dr. Dahan said he uses a similar approach as the authors, except that he employs a larger scleral flap and he rarely needs to release the sutures. He avoids blockage of the tube, which was the most common complication experienced by Dr. Kanner and colleagues, through routine use of anterior chamber maintainer (ACM) during all glaucoma operations.

“The ACM ensures intraoperative control of the IOP and also prevents any debris from blocking the device lumen during the operation,” Dr. Dahan said.

Drs. Ahmed and Dahan noted that a key factor is patient selection. Dr. Ahmed avoids using the Ex-PRESS in neovascular glaucoma cases and instead relies on drainage tubes. The best indication for the Ex-PRESS shunt, Dr. Dahan said, is an elderly glaucoma patient who also has a senile cataract. Combined procedures are indicated in cases of narrow angle glaucoma with senile cataract.

Editors’ note: Drs. Dahan and Ahmed have financial interests with Optonol (Kansas City, Kan.). Dr. Mundorf has no financial interests related to his comments.

Contact information

Ahmed: 416-625-3937, ike.ahmed@utoronto.ca
Dahan: elie.dahan@gmail.com
Mundorf: 704-334-3222, tommundorf@aol.com

Combined cataract, glaucoma procedures given a boost Combined cataract, glaucoma procedures given a boost
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