Spotlight on Technology & Technique

Endothelium Inserter Increases Safety

By Samantha Stahl, Assistant Editor

Patients requiring keratoplasty should be thankful for the less invasive treatments that have developed in the last few years. As surgeons learn to adopt the newer techniques for corneal endothelial transplants, a crop of devices has appeared on the market to ease the transition.

The Tan EndoGlide endothelium insertion system from Angiotech Pharmaceuticals aims to make these procedures easier for the surgeon while enhancing safety for the patient.

Cell Preservation

While Descemet's stripping (automated) endothelial keratoplasty (DSEK/DSAEK) has rapidly grown in popularity, reducing endothelial cell loss is still a continual struggle. With the Tan EndoGlide, the donor tissue is folded and loaded into a cartridge before insertion through the anterior chamber. A pull-through technique is performed with intraocular forceps on the nasal side to grasp and unload the donor tissue.

Because unfolding the tissue tends to be a larger surgical challenge than folding and loading, the device seeks to provide better control for surgeons and maximizes the ability to preserve endothelial cells after the cartridge is inserted.

“It's a very interesting technique because it allows the tissue to deploy smoothly inside the eye,” says George Rosenwasser, MD, a cornea specialist in Hershey, Pa. After performing around 500 DSAEK procedures, he sought out the device because he wanted a product that would allow a smaller incision and safer wound.

The Tan EndoGlide allows for more controlled placement of donor tissue.

The EndoGlide, he explained, was invented by Donald Tan, MD, director of the Singapore National Eye Centre, who found that it was difficult to get donor tissue into smaller Asian eyes. Dr. Tan found that working through a closed system with a 5.1-mm incision would do the trick. By limiting the opportunity for iatrogenic damage, patients could expect better outcomes.

As expected, Dr. Rosenwasser says that the device works best with optimal donor thickness—around 150 microns—as loading the device is more difficult when the tissue is too thin and cell loss may be greater when the tissue is too thick.

Dr. Rosenwasser performed a study that will be published later this year testing DSAEK operative techniques, including procedures with the Tan EndoGlide. He says he was able to use a 5.5-mm to 6.0-mm incision with the device and had acceptable amounts of endothelial cell loss at up to six months follow-up. Average cell density was 2244 ± 706 cells per square millimeter, representing an average loss of 20% ± 19% from the preop cell measurement.

Physician Feedback

Dr. Rosenwasser says that he finds use of the Tan EndoGlide particularly advantageous for patients with pre-existing anterior chamber lenses, hyperopic individuals and those at risk for choroidal hemorrhage because of the ability to keep the eye completely pressurized during surgery.

A new EndoGlide is used for each procedure, making set up quicker in the operating room. However, Dr. Rosenwasser points out that ASCs need to consider this in the bundled fee they charge.

The device was designed for insertion through a scleral tunnel incision because of the reduction in astigmatism, but limbal or corneal incisions can also be used. A lip on the cartridge allows the surgeon to insert through the wound without an increased risk of iris prolapse.

“When you try to unfold the donor inside the eye, that's when a lot of damage can occur. But the Tan EndoGlide gives an edge, particularly to the novice surgeon and especially over forceps.” OM

For more information, visit www.angiotech.com.