Eyeworld

EW RESIDENTS 68 by Zachary Elkin, MD, MPH, Daniel Choi, MD, and Brian Toy, MD, Byers Eye Institute at Stanford, Stanford University School of Medicine There are two MIGS technologies currently approved for combination with phaco. I invited the Stanford residents to review this study in the August JCRS that compares these two MIGS procedures. –David F. Chang, MD, EyeWorld journal club editor G laucoma is a progressive optic neuropathy that is widely considered the second leading cause of blindness worldwide. 1 Historically, the gold standard for surgical management has been filtering surgery. But trabeculectomy and tube shunts tend to have a high percentage of side effects. According to the Tube Versus Trabeculectomy (TVT) study, 21% early and 34% late postop complications were reported with tubes and 37% early and 36% late with trabeculectomy. 2 Recently, the development of ab interno glaucoma procedures has improved safety by sparing con- junctiva, reducing complications associated with filtering surgery, and allowing earlier intervention on less severe glaucoma. The FDA has ap- proved 2 trabecular meshwork-based microinvasive glaucoma surgeries (MIGS), namely the iStent (Glaukos, Laguna Hills, Calif.) and Trabectome (NeoMedix, Tustin, Calif.). iStent received FDA approval in 2012 in combination with cataract surgery. The Trabectome was approved in 2004 as a standalone procedure or in conjunction with cataract surgery. The iStent is a heparin-coated titanium L-shaped device that is im- planted ab interno into Schlemm's canal with the snorkel protruding into the anterior chamber. Prior case series suggest that compared to cataract surgery alone, combined iStent and cataract surgery is safe and resulted in a 1-year reduction in IOP by 8–27% and a reduction in IOP medications by 80–100%. 3,4 Additionally, there has been interest in the placement of multiple iStents to help access additional collector channels while bypassing circumfer- ential resistance in Schlemm's canal. A study of 53 eyes demonstrated a mean reduction in IOP from 18 mm Hg preop to 13.8 mm Hg with 2 stents and 14.8 mm Hg with 3 stents. 5,6 In comparison, the Trabectome is a bipolar electrocautery device facilitating an ab interno approach to opening Schlemm's canal to the anterior chamber by removing the trabecular meshwork. Outcomes have been described in small sam- ple prospective case series 7 and a larger, retrospective, single-center review. 8 The initial study cited by the authors who invented the device reported sustained IOP decreases to the mid teens and reduction in medications (mean 1.2 to 0.4) at 12 months. 7 More recently, a large retrospective review of patients who underwent ab interno trabeculot- omy at the Mayo Clinic with and without cataract extraction found at 2 years a 29% reduction in IOP and 38% reduction in number of medications. 8 However, only 22% achieved clinical success (defined as IOP <18 mm Hg and >20% reduc- tion from preop IOP) and 26.8% required an additional surgery. Despite the reported benefit and growing popularity, there have been no head-to-head studies of these 2 MIGS procedures. In "The efficacy and safety of combined cataract surgery with two trabecular micro-bypass stents versus ab-interno trabeculotomy," Khan et al published a retrospective, inter- ventional, non-randomized case series comparing these 2 MIGS pro- cedures. The study looked at a total of 49 eyes with 2 stents implanted and 52 eyes that underwent trabecu- lotomy using the Trabectome device by 3 surgeons in 3 different practices Review of "The efficacy and safety of combined two trabecular micro-bypass stents versus ab- Douglas Fredrick, MD, ophthalmology residency program director, Stanford University School of Medicine Stanford residents, from left to right: Wenshin Lee, MD, Jennifer Kung, MD, Edward Wood, MD, David Myung, MD, Brian Toy, MD, Lisa Chen, MD, Kaidi Wang, MD, Zachary Elkin, MD, Carson Lam, MD, Daniel Choi, MD Source: Stanford University School of Medicine The efficacy and safety of combined cataract surgery with two trabecular micro-bypass stents versus ab-interno trabeculotomy Michelle Khan, MD, Hady Saheb, MD, MPH, Arvind Neelakantan, MD, Ronald Fellman, MD, Zachary Vest, MD, Paul Harasymowycz, MD, Iqbal Ike K. Ahmed, MD J Cataract Refract Surg (Aug.) 2015;41. Article in press Purpose: To compare outcomes of combined cataract surgery with trabecular micro-bypass stents and ab-interno trabeculotomy in patients with open angle glaucoma. Setting: Patients undergoing glaucoma surgery at three subspecialty clinics. Design: Retrospective, interventional, non-randomized, comparative case series. Methods/Intervention: Patients (average age=76.5 years±12 years) with primary open-angle, pseudoexfoliative, or pigmentary dispersion glaucoma were included. 49 eyes underwent phacoemulsification and 2 stent implantations, and 52 eyes underwent phacoemulsification and trabeculotomy surgery with 12 months postoperative follow- up. Primary outcome measures were intraocular pressure (IOP), postoperative medications, success (IOP ≤18 mm Hg, no glaucoma medications or reoperations), and postoperative adverse events. Results: ANOVA indicated significant reduction in mean IOP from baseline to 12 months for stent (19.6±5.3 mm Hg to 14.3±3.1 mm Hg, P<0.001) and trabeculotomy (20.6±6.8 mm Hg to 17.3±6.5 mm Hg, P<0.001), and lower mean IOP at 12 months in the stent group (P=0.01). Median number of glaucoma medications reduced from baseline to 12 months for both groups, and was lower in the stent group at 3, 6, and 12 months. 39% of patients in the stent group and 14% in the trabeculotomy group achieved success at 12 months (P=0.006). Incidence of hyphema was lower in the stent group (P=0.008). Conclusions: Both types of surgery achieved a significant reduction in IOP and medication use at 12 months, with higher success in the stent group and reduced incidence of postoperative hyphema. EyeWorld journal club August 2015

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