CASE STUDY

Minishunt May Lead to Better Outcomes

The Ex-PRESS minishunt may enhance results in certain glaucoma patients.

BY MALIK KAHOOK, M.D.

The ultimate goal of glaucoma surgery, as we know, is to lower IOP. The Ex-PRESS minishunt (Optonol Ltd., Kansas City, Kan.) provides a relatively novel option for enhancing trabeculectomies combined with some distinct advantages in certain patients. The process of inserting the device is quick and offers several intra- and postoperative advantages, which I will review in the case I present below.

Reading the Fine Print

Indications for using the Ex-PRESS minishunt are similar to those for trabeculectomy, including failure of maximal medical therapy to control IOP, the need for penetrating surgery and in cases of failed filtration surgery requiring reoperation. Contraindications as noted by the manufacturer include microphthalmia and nanophthalmia, diabetic neovascular glaucoma, congenital glaucoma, acute angle-closure glaucoma and chronic narrow-angle glaucoma. Please note that this device is not well tested in the pediatric age group.

Case Study

The following is a case involving a 48-year-old, African-American male with history of bilateral uveitic glaucoma who underwent Ex-PRESS minishunt implantation.

■ Preoperative. The patient's previous history was significant for ankylosing spondylitis, with the most recent bout of iritis occurring 1 year previously. He was pseudophakic bilaterally and was not taking topical steroid drops. There was no active iritis. The left eye has been relatively stable for 5 years with well-controlled IOP on monotherapy with pressure of 13 mm Hg.

The right eye IOP, then at 32 mm Hg, had steadily increased despite maximal medical therapy. On gonioscopy, the angles were open with only a few anterior synechiae.

Visual field testing revealed bilateral superior and inferior arcuate scotomas worse in the right eye.

■ Treatment. After discussions with the patient, we decided to proceed with Ex-PRESS minishunt implantation in order to better control postoperative pressure with a lower chance of hypotony. This procedure, using a fornix-based approach, was done under a scleral flap with use of mitomycin C (0.4mg/mL) for 2 minutes.

The square scleral flap was sutured into place with a single 10-0 nylon suture at the apex and the conjunctiva was re-approximated using two interrupted 8-0 vicryl sutures on either side of the peritomy.

■ Follow-up. Postoperative therapy for this patient included a topical fourth-generation fluoroqinolone and atropine 1% for the first week, as well as prednisolone acetate 1% drops four to six times per day with a slow taper. After 3 months, the patient maintained an IOP between 11 mm Hg to 13 mm Hg with no medications and has a low diffuse bleb extending posteriorly. His left eye remains stable on monotherapy.

The Results You Can Expect

Advantages to using the Ex-PRESS over traditional trabeculectomy include:

► Decreased time of surgery: Surgeons can save a few minutes by avoiding use of trabeculectomy punch and iridotomy.

► Reproducibility: The size of the opening in to the anterior chamber is made more reproducible by avoiding use of a punch and relying on the constant internal diameter of the minishunt.

► Avoiding a surgical iridotomy: This lessens the post-operative inflammation, a certain advantage in patients with history of uveitis.

► Decreasing the chance of postop hypotony: Uveitic patients are more prone to postop hypotony. Lessening the chance of postop hypotony occurs in this case due to controlled flow through a uniform-sized device (Figure).

Figure. This is a 6-week postop photo following trabeculectomy and Ex-PRESS minishunt implantation. The minishunt creates a uniform-sized opening for fluid flow into the bleb.

Case Study

The single case presented here illustrates some of the advantages of the Ex-PRESS minishunt as an adjunct to penetrating surgery for patients with glaucoma and uncontrolled elevation in IOP. Long term follow-up with a large number of patients and different physicians will help us better understand the Ex-PRESS minishunt's role in the glaucoma treatment algorithm. I am encouraged by the experiences I have had thus far; however, direct head-to-head studies are needed to compare this minishunt to standard trabeculectomies and glaucoma drainage devices. These studies will help us better understand the true advantages and disadvantages of each procedure. OM

Malik Kahook, M.D., is assistant professor of ophthalmology and director of clinical research in the Department of Ophthalmology at the University of Colorado at Denver & Health Sciences Center. Dr. Kahook acknowledges no financial interest in the products or companies mentioned herein.