Kahook Dual Blade Program at Vance Thompson Vision
KDB Top Line
The Kahook Dual Blade (KDB) is an elegant, single use, ophthalmic blade designed to excise a clean strip of trabecular meshwork. It can be a stand-alone procedure or performed in combination with cataract surgery in patients with mild to moderate glaucoma.
WHAT IS THE PROCEDURE
The Kahook Dual Blade (New World Medical) is a simple yet elegant device designed to reduce IOP through the removal of a section of trabecular meshwork (TM) and the inner wall of Schlemm canal. Under direct gonioscopic visualization, the dual blade is inserted through a clear corneal incision and advanced to the opposite angle. The sharp tip of the device is used to pierce the TM and enter the canal. As the instrument advances in the canal, the ramp of the device gently elevates the TM toward the dual blades on either side of the device where it is incised. The result is a nearly complete excision of the TM from an ab interno approach. The procedure of incising TM to increase aqueous outflow has long been established as a means of reducing IOP in glaucoma. Long-term success in adults with the disease has been limited, however, in part due to the residual TM leaflets that can scar closed postoperatively.
WHEN AND WHY DO IT?
Indications and Candidacy
KDB is indicated for the treatment of open-angle glaucoma in patients with uncontrolled IOP, with the likelihood of progressive nerve injury, on maximally available or tolerable medical treatment. However, because of the favorable risk profile of KDB compared to traditional filtering glaucoma surgery, the technique has been gaining acceptance for more indications, including narrow-angle glaucoma. Currently, KDB is used in a wide range of glaucoma types, including open-angle, pseudoexfoliation, pigment dispersion, uveitic, steroid-induced, among others. Typical KDB surgery candidates are phakic or pseudophakic with a clear gonioscopic view of the angle. Further, in order to ensure a sufficient gonioscopic view. KDB can be performed in combination with phacoemulsification in patients with a visually significant cataract requiring further reduction of glaucoma medications or IOP.
HOW IS THE PROCEDURE DONE?
The dual blade device is designed with a taper at the tip to allow for smooth entry of the blade into Schlemm's canal. Once properly seated in the canal, the device is advanced along the TM. The ramp at the distal end of the instrument elevates TM tissue and guides it toward the blades on either side of the device, which then cleanly incise the tissue to allow for easy removal. By elevating the TM and placing it on stretch prior to cutting, the design allows for cleaner removal of tissue and minimizes damage to adjacent structures. The angle of the distal cutting surface and the size of the device shaft are engineered to allow for maximum clock hour treatment through a single clear corneal incision.
Post Op Care
Cataract Extraction plus KDB
Drop-A-Day Approach: Dex-Moxi-Ketor injection at conclusion of the cataract plus KDB procedure. The patient takes Ilevro, Prolensa or Bromsite one time a day for one month.
Standard Approach: Vigamox four times a day for one week, prednisolone acetate 1% four times a day for one week then two times a day for three weeks, Ilevro, Prolensa or Bromsite one time a day for 4 weeks.
Post-op follow-up care is one day, one week, one month, and three months. The addition or subtraction of patient’s glaucoma medications is done on a case by case basis. The severity of the glaucoma present and the level of IOP is considered when adding or subtracting glaucoma medications. Tapering of prednisolone acetate 1% is encouraged if post surgical inflammation is controlled or minimal in order to decrease the chances of IOP spikes.
KDB in a Pseudophakic Eye
Vigamox four times a day for one week, Ilevro/, Prolensa or Bromsite one time a day for four weeks.
Post-op follow-up care is one day, one week, one month, and three months. The addition or subtraction of patient’s glaucoma medications is done on a case by case basis. The severity of the glaucoma present and the level of IOP is considered when adding or subtracting glaucoma medications.
The most common reasons for surgical failure are incomplete or improper removal of the TM, or damage to the SC or surrounding tissue which results in wound healing processes. The most common postoperative complication is a hyphema, but surgical intervention is rare, and resolution of the hypema is common within the first 24 hours. Consistent with other types of MIGS, postoperative IOP spikes of 10 mmHg or higher can be observed, although they typically resolve without the need for further operations.