Catheter-independent suture probe canaloplasty with suprachoroidal drainage

To introduce the novel technique of suture probe canaloplasty with suprachoroidal drainage (SCD) as a catheter-independent and cost-saving method to perform non-penetrating glaucoma surgery.

Prospective interventional study with a 12-month follow-up. A standard 6/0 polypropylene suture is twisted in a special manner to create a double helix with a small loop at its end. Then canaloplasty with SCD is performed, but instead of using the standard canaloplasty catheter, Schlemm's canal is probed with the twisted suture. After 360° probing, a 10/0 polypropylene suture is thread through the loop and the twisted 6/0 suture is pulled backwards through Schlemm's canal. The 10/0 suture in Schlemm's canal is tied firmly and hyaluronic acid is injected into the suprachoroidal space.

In total, 74 eyes that underwent suture probe canaloplasty with SCD were included. In 57 cases, probing of Schlemm's canal with the twisted 6/0 suture succeeded. Seventeen eyes had adhesions in Schlemm's canal which made probing with the suture impossible so that the surgeon switched in 12 cases to microcatheter-guided canaloplasty with SCD. While this was successful in five further cases, the adhesions seemed surely not be overcome and SCD with collagen sheet implantation was directly performed. In four additional cases after successful probing, the suture cut through trabecular meshwork; hence a 360° suture trabeculotomy was performed. After successful suture probe canaloplasty with SCD, intraocular pressure (IOP) decreased by 39.2% (from 19.8 ± 4.3 mmHg with 3.4 ± 0.7 different IOP-lowering eye drops to 12.0 ± 1.9 mmHg with 0.6 ± 0.9 eye drops). Three patients did not achieve sufficient IOP levels and, therefore, underwent 360° suture trabeculotomy during follow-up. No serious or sight-threatening complications occurred.

Suture probe canaloplasty + SCD yields the opportunity to conduct canaloplasty with SCD more cost-effectively with a safety profile and IOP-lowering effect comparable to conventional canaloplasty. In cases where probing with the suture fails. there still remains the option to use a conventional microcatheter or to switch to SCD with collagen sheet implantation.