Combining twin-site microincision surgery and trabeculectomy seems a viable alternative to coaxial phacoemulsification

Key Points

Madurai, India-The combination of twin-site microincision cataract surgery and trabeculectomy seems to be a viable alternative to twin-site coaxial phacoemulsification and trabeculectomy to treat cataract in the presence of medically uncontrolled glaucoma. The procedure is safe, provides adequate decreases in IOP 2 years postoperatively, and restores vision more quickly, according to Neeraj Varma, MS, who is affiliated with Aravind Eye Hospital & P.G. Institute of Ophthalmology, Madurai, India.

Varma and colleagues conducted a study to evaluate the safety, efficacy, visual outcome, and postoperative IOP control achieved with the two procedures. Included patients had primary open-angle glaucoma refractory to maximal medical therapy and visually significant cataracts. Patients were excluded if they had only one eye or had a corneal or posterior segment disorder or previous intraocular surgery, connective tissue disorder, or history of systemic steroid use, Varma explained.

Thirty patients were included in this prospective review. Half of the patients were randomly assigned to twin-site microincision cataract surgery and trabeculectomy, and the other half were randomly assigned to twin-site coaxial phacoemulsification and trabeculectomy. The average postoperative follow-up was 2 years.

From two separate incisions, trabeculectomy was performed simultaneously with either microincision cataract surgery or coaxial phaco. The microincision or phaco procedures were performed through temporal clear corneal incisions followed by standard trabeculectomy from the 12 o'clock position. No pharmacologic modulation was used. Hydrophilic acrylic IOLs were implanted in all patients.

In the patients who underwent twin-site microincision cataract surgery and trabeculectomy after a fornix-based conjunctival flap was created, a partial-thickness limbal-based scleral flap was created. The anterior chamber was not entered at this stage of the procedure. The procedure was completed from two temporal clear corneal microincisions, and the IOL was implanted in the bag, Varma explained.

The trabeculectomy was performed, and the sclera and conjunctiva were closed with 10-0 nylon sutures. The mean ultrasound time was 32 seconds.

In the group of patients who underwent twin-site coaxial phacoemulsification and trabeculectomy, a fornix-based conjunctival flap was created and then a triangular limbal-based partial-thickness scleral flap was made. As in the other procedure, the anterior chamber was not entered at this stage. On the temporal side, a clear corneal temporal incision was made, phaco was performed, and then the IOL was injected into the bag. The pupil was constricted with pilocarpine, and the wounds were hydrated. A trabeculectomy was performed, and the sclera and conjunctiva were then closed with interrupted sutures. The mean ultrasound time was 54 seconds, Varma reported.

Intraoperative miosis

"The development of intraoperative miosis in both surgical groups did not interfere with the completion of phacoemulsification. The group that underwent twin-site coaxial phacoemulsification and trabeculectomy required injection of air into the anterior chamber," Varma reported.

"Postoperatively, substantial inflammation occurred in both groups, and this responded well to routine postoperative treatment," he said. "Shallowing of the anterior chamber responded well in 1 to 2 days with pressure patching. Transient high IOP in the group that underwent microincision cataract surgery and trabeculectomy responded well to digital massage. If IOP remained high, then patients received antiglaucoma medications."

Varma and his colleagues found that the mean IOP of less than 20 mm Hg was achieved by the end of 18 to 24 months in both surgical groups.

"IOP control was marginally better in the group that underwent microincision cataract surgery and trabeculectomy," he stated.

The patients in both surgical groups had a best-corrected visual acuity greater than 6/12 by 24 months postoperatively. Twelve patients in the microincision cataract surgery and trabeculectomy group, and 10 patients in the coaxial pha co emulsification and trabeculectomy group, achieved this level of visual acuity, Varma said.

"Early and late mean postoperative IOP levels decreased significantly in comparison to the preoperative levels, and there was no significant difference in the IOP control 18 to 24 months after surgery between the two surgical groups," he said.

"Twin-site microincision cataract surgery and trabeculectomy is safe, it provides adequate decreases in IOP over 2 years, the visual restoration is faster, and the procedure is a viable alternative to twin-site coaxial phacoemulsification and trabeculectomy," Varma concluded.