MICRO-STENT SURGERY

Ab interno implantation of a supraciliary micro-stent (CyPass Micro-Stent, Transcend Medical) alone or in combination with cataract surgery is a safe micro-invasive procedure for treatment of open angle glaucoma that provides significant and sustained lowering of intraocular pressure (IOP) and medication, reports Magda Rau MD.

Speaking at the XXXII Congress of the ESCRS in London, UK, Dr Rau reported one-year outcomes for her series of 33 eyes operated on between May 2009 and July 2011. All eyes had best corrected visual acuity (BCVA) better than 0.3. Twenty-four eyes underwent concomitant phacoemulsification and intraocular lens (IOL) implantation. All glaucoma medications were stopped postoperatively and reintroduced if needed to control IOP.

Mean IOP was 22.3mmHg in the combination glaucoma-cataract surgery group at baseline. At 12 month follow-up mean IOP was 15mmHg. Mean medication use was reduced from 1.8 at baseline to 0.8 during the same period.

For eyes undergoing implantation of the stent as a standalone procedure, mean baseline IOP was 26mmHg on a mean of 1.3 medications. Five eyes were seen at 12 months and had a mean IOP of 13.2mmHg while on an average of 0.8 medications.

Adverse events

Dr Rau reported there were no sight-threatening adverse events in the series or cases of inflammation. Minor intraoperative bleeding was observed in three eyes without development of hyphaema, and two eyes developed transient hypotony that resolved within one month.

Early migration of the implant occurred in one patient, due to renal colic attack with according vomiting postoperatively, and was addressed with a repositioning procedure. The patient recovered without any clinical sequelae and had an IOP of 13mmHg at 24 months.

“We know that glaucoma remains the leading cause of blindness in industrialised countries and that maximally tolerated medication does not sufficiently reduce IOP in many patients,” said Dr Rau, head of Eye Clinic Cham, Germany.

“Although conventional glaucoma surgery can be very effective, it also has a high risk of sight-threatening complications. Implantation of this supraciliary micro-stent appears to be a promising alternative to meet our need for less invasive surgical interventions that can control IOP while reducing dependence on medications,” she said.

The micro-stent creates a permanent pathway for aqueous drainage from the anterior chamber towards the suprachoroidal space by harnessing the natural negative pressure gradient in the eye. It is made of a biocompatible, non-degradable polyimide material. It measures 6.2mm in length, has an inner diameter of 0.3mm, and features proximal retention rings that help to stabilise its position in the supraciliary space.

The device is implanted through a clear cornea incision (minimum 1.5mm), thus sparing the conjunctiva and sclera. Dr Rau said that she usually uses a 2.0mm incision when performing the implantation as a standalone procedure, while in combination cases she places the device through the 2.2 to 2.8mm cataract incision after the IOL implantation is done.

“Operating through a 2.0mm or larger incision gives me a little more flexibility in choosing the optimal place for the micro-stent,” she said.

Magda Rau: info@augenklinik-cham.de