This article is more than 5 years old. Information may no longer be current.
BLOG: Rejuvenating and reintroducing older glaucoma surgery
This rapidly progressing era of glaucoma treatment is exposing providers to new medical and surgical options for patient care. However, sometimes improvement of older surgical procedures can provide alternative solutions that can be just as successful.
One area that has seen such change is in surgery that unroofs Schlemm’s canal in the form of trabeculotomy and goniotomy. In the past, trabeculotomy was preformed ab externo, which is unfavorable in our current therapeutic landscape because it disrupts the conjunctival tissue. The introduction of gonioscopy-assisted transluminal trabeculotomy and use of the Trab360 (Sight Sciences) instrument have converted this procedure to a much better ab interno approach. We now see another step in the evolution of this area of surgery with the introduction of the Kahook Dual Blade (KDB, New World Medical).
The KDB is a single-use ophthalmic blade that allows surgeons to effectively remove a section of trabecular meshwork, allowing direct flow of aqueous humor from the anterior chamber to Schlemm’s canal. The blade is introduced into the anterior chamber through a 1.2-mm clear corneal temporal wound, which can be the same wound as the one used for cataract surgery or the wound can be part of a standalone procedure. The sharp tip of the blade is used to incise through the trabecular meshwork and enter into Schlemm’s canal. As the blade is rotated around, the section of trabecular meshwork in contact with the blade tip is elevated up its ramp. The sharp dual blades on each side of the ramp cut the trabecular meshwork. The blade is then removed from its position in Schlemm’s canal and rotated around. An entry incision is made again through the trabecular meshwork and into Schlemm’s canal distal to where the initial incision ended. The blade is rotated in the opposite direction of the first incision until it cleaves off the common section of trabecular meshwork. The result is a patent pathway for aqueous to drain into Schlemm’s canal.
The benefits of using the KDB include the following:
1. The width of the blade naturally fits the dimensions of Schlemm’s canal, allowing for safe yet maximal removal of trabecular meshwork width.
2. The heel of the blade sits against the outer wall of Schlemm’s canal and safely glides across it as the blade is advanced during the procedure, which ensures its safe rotation.
3. The tip of the blade allows for accurate visualization of how much tissue will be removed, permitting a precise removal of trabecular meshwork section.
4. The blade allows the surgeon to select and remove the desired section of trabecular meshwork.
Advances in glaucoma surgery are occurring rapidly, allowing surgeons to now perform surgeries that were once obsolete. The introduction of the KDB provides ophthalmologists another method to remove diseased trabecular meshwork and unroof Schlemm’s canal to restore the natural pathway of aqueous drainage. This procedure adds yet another tool in the armamentarium to better care for our patients with less risk compared with that in the past.
Disclosure: Teymoorian reports no relevant financial disclosures.