Kahook Dual Blade / Trabectome safe and effective at lowering IOP and medication burden in glaucoma patients
Glaucoma is a progressive optic neuropathy with characteristic visual field loss and is the second leading cause of global blindness. Intraocular pressure (IOP) is the only modifiable risk factor to decrease vision loss from glaucoma and can be controlled with IOP lowering medications, laser, and surgery. Surgical options include filtering surgeries, tube shunts and a growing selection of microinvasive glaucoma surgery (MIGS) devices. The trabecular meshwork (TM) is the site of greatest resistance to aqueous humor outflow in the eye, and removing this tissue via goniotomy or trabeculotomy reduces IOP by increasing aqueous outflow.6 The Kahook Dual Blade (KDB) and Trabectome (Microsurgical Technology) are two MIGS devices that excise or ablate TM and have been shown to be effective at lowering IOP via this similar mechanism, both as standalone procedures and at the time of cataract surgery.
The purpose of the study by Fliney et al was to compare the efficacy and safety of KDB versus Trabectome, both in combination with cataract surgery. Given both devices similarly remove TM in the nasal angle, the authors hypothesized that KDB and Trabectome will have comparable levels of success and efficacy
Authors carried out a Retrospective chart review comparing eyes after KDB or Trabectome with cataract surgery at 2 academic centers. Surgical success was defined as IOP< 21 mmHg with ≥20% IOP reduction at post-operative month 12 (POM12). Changes in IOP, number of glaucoma medications, and adverse events were assessed.
Ninety eyes in the KDB group and 125 eyes in the Trabectome group were included. Mean changes in IOP at POM12 were −1.9 ± 4.9 mmHg (11.2%, P = 0.002) in the KDB group and −3.5 ± 5.5 mmHg (19.1%, P < 0.001) in the Trabectome group, without a significant difference between the groups (P = 0.20).
Mean change in glaucoma medications at POM12 was −0.8 ± 1.5 in the KDB group (58%, P < 0.001) and −0.3 ± 1.3 (38%, P = 0.003) in the Trabectome group, with KDB having a greater decrease in medications (P = 0.02).
The percentage of eyes achieving success was 30% for the KDB group and 54% for the Trabectome group (P = 0.01).
Hyphema was the most common complication, with an incidence of 3% for the KDB group and 14% for the Trabectome group (P = 0.01).
In this retrospective comparative analysis of KDB and Trabectome combined with cataract surgery, KDB showed a greater reduction in medications, while Trabectome had a higher success rate despite no statistically significant difference in IOP change between these groups. KDB had a greater decrease in medications at 12 months of −0.5 medications with 58% of patients having a decrease in medications compared with 38% of Trabectome patients. Although there was no significant difference in IOP change at each time point between the two groups, 54% of eyes in the Trabectome group met the definition of success versus 30% of eyes in the KDB group at 12 months. Both surgeries had excellent safety profiles with no sight-threatening complications. There was a higher rate of hyphema in the Trabectome group which was self-limited and not associated with anticoagulation use.
While the KDB cohort showed greater reduction in number of glaucoma medications and the Trabectome cohort met our criteria for surgical success at a greater rate compared to KDB, both devices performing goniotomy in combination with cataract surgery were similarly safe and effective. Although there were statistically significant differences in medication reduction and success rates, the outcomes were comparable when considering the inherent limitations of the study. No metric analyzed in the study heavily favored one surgical device over the other. Additional studies including randomized control studies are needed to fully assess the differences in outcomes for different minimally invasive glaucoma surgeries.
Source: Fliney et al; Clinical Ophthalmology 2023:17 145–154
https://doi.org/10.2147/OPTH.S391527
