COMMENTARY

Is Kahook Dual Blade Goniotomy a Better Option for Glaucoma?

Shuchi B. Patel, MD

Disclosures

May 01, 2020

Goniotomy was greeted as a step forward in the treatment of pediatric glaucoma, but it has been less successful in achieving sustained intraocular pressure (IOP) reductions in adult patients with glaucoma, who often experience increasing IOP after this surgery. It is believed that the higher IOP stems from the cleft created by this surgery closing (or scarring) over time. Trabectome surgery minimizes this risk for surgical failure by ablating the trabecular meshwork rather than creating a direct incision. Trabectome has also been reported to lower IOP by approximately 31%, which is more than what is seen with cataract extraction alone. Despite these favorable outcomes, trabectome equipment can be prohibitively expensive.

The Kahook Dual Blade (KDB) is a novel technology that removes an entire strip of the trabecular meshwork, similar to trabectome. However, preclinical evidence suggested that KDB may reduce the risk for cleft closure, with possibly even less damage to surrounding tissue than with conventional goniotomy or trabectome. It may also require less of a financial investment because KDB is a single-use, disposable instrument that does not require other equipment.

In a recent retrospective chart review, Kornmann and colleagues report the outcomes of KDB goniotomy as a standalone procedure (11 eyes) or in combination with cataract extraction (100 eyes) in 90 adult patients (mean age, 70 years).

Preoperatively, mean IOP was 17.1 mm Hg and patients were taking an average of 2.4 IOP-lowering medications. Statistically significant reductions in both postoperative IOP and the number of IOP-lowering medications used were seen at 1 month post-procedure and sustained for at least 12 months thereafter. Twelve months after KDB goniotomy, patients had a mean IOP of 14.7 mm Hg and were taking an average of 1.6 IOP-lowering medications (P < .004 and P < .001 vs baseline, respectively). Over the course of 12 months, 4.6% of eyes required subsequent reoperation for IOP lowering.

An Easy Procedural Adaptation

If you're familiar with angle-based surgery or already performing trabectome, KDB goniotomy is an easy procedural adaptation. It also does not add much time to the procedure when done in conjunction with cataract surgery.

The IOP lowering accomplished was modest, at a mean of < 3 mm Hg. There were wide variations, however, and patients with higher preoperative IOP had much greater decreases in pressure post-procedure. Further analysis of ideal patient selection could swing the rates of IOP reduction even higher.

Given the low complication rate—the most common complication was hyphema that self-resolved—KDB goniotomy appears to be a safe procedure for lowering IOP in select patients. One caveat is that it does preclude laser trabeculoplasty or placement of iStent because the trabecular meshwork has been removed. Therefore, it is necessary to evaluate each patient individually to determine which procedure is best suited to accomplish lower IOP while preserving the most options for the future.

Shuchi B. Patel, MD, is director of glaucoma services in the Department of Ophthalmology at West Palm Beach VA Medical Center in Florida. She explores the ever-changing glaucoma space for Medscape, including advances in diagnostics and treatments.

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