Microinvasive Glaucoma Surgery Device Research Articles

Comparison of Hydrus and iStent microinvasive glaucoma surgery implants in combination with phacoemulsification for treatment of open-angle glaucoma: systematic review and network meta-analysis

ObjectivesTo compare the efficacy and safety of two Schlemm’s canal-based microinvasive glaucoma surgery (MIGS) devices, the Hydrus Microstent and the iStent Trabecular Bypass combined with phacoemulsification for treatment of open-angle...

Cost-utility analysis of trabecular micro-bypass stents (TBS) in patients with mild-to-moderate open-angle Glaucoma in Italy

BackgroundGlaucoma is a disease characterized by progressive damage of the optic nerve. Several therapeutic options are available to lower intraocular pressure (IOP). In primary open-angle glaucoma (POAG) patients with inadequate IOP control (or controlled with multiple medical therapies or for whom medical therapy is contraindicated), the implantation of micro-invasive glaucoma surgery devices (MIGS) and concomitant cataract surgery has proved to be more effective in reducing intraocular pressure (IOP), as compared to cataract surgery alone. The objective of this study was to assess the cost-effectiveness of iStent inject® device with concurrent cataract surgery vs. cataract surgery alone, in patients with mild-to-moderate POAG, adopting the Italian National Health Service (NHS) perspective.MethodsSimulation of outcomes and costs was undertaken using a Markov model with 4 health states and one-month cycles, that is used to simulate the prognosis of these patients. Efficacy data were obtained from the randomized clinical trial (RCT). A lifetime horizon was adopted in the analysis. A discount rate of 3.5% was applied to both costs and effects. The Italian National Healthcare Service (NHS) perspective was considered, therefore only healthcare direct costs (acquisition of main interventions and subsequent procedures; medications; monitoring and follow-up; adverse events). Model robustness was tested through sensitivity analyses.ResultsResults of the base-case analysis showed that the total lifetime costs were higher in the iStent inject® + concurrent cataract surgery, compared with the cataract surgery alone group (€8368.51 vs. €7134.71 respectively). iStent inject® + concurrent cataract surgery was cost-effective vs. cataract surgery alone, with an incremental cost-effectiveness ratio of €13,037.01 per quality-adjusted life year (QALY) gained. Both one-way deterministic and probabilistic sensitivity analyses confirmed robustness of base-case results. The cost-effectiveness accessibility curve (CEAC) showed that iStent inject® + cataract surgery would have a 98% probability of being cost-effective, compared to cataract surgery alone, when the willingness to pay (WTP) is equal to €50,000 per QALY gained.ConclusionsThe results of the cost-utility analysis confirm that iStent inject® + cataract surgery is a cost-effective option for the treatment of patients affected by mild-to-moderate POAG, compared with cataract surgery alone, when evaluated from the Italian NHS perspective.

Mid-term evaluation of the safety and efficacy of the iStent trabecular micro-bypass system combined with phacoemulsification.

Micro-invasive glaucoma surgery (MIGS) and MIGS devices have been gaining increasing attention in recent years. One such device is the trabecular micro-bypass stent, or iStent® (Glaukos Corporation, Laguna Hills, USA). To evaluate the safety and efficacy of the minimally invasive ab interno surgical implantation of a trabecular bypass during cataract surgery in reducing intraocular pressure (IOP) in patients with mild and moderate open-angle glaucoma and cataracts. The study was a prospective, uncontrolled, interventional case series (a prospective study of a case series), including 54 patients with a mean age of 72 years. All subjects underwent ab interno implantation of a single iStent together with cataract surgery. The corrected distance visual acuity (CDVA), IOP, anti-glaucoma medications, visual field, and number and type of complications were investigated after surgery. The patients were followed up at 1, 7, and 30 days, and 3, 6, 12, 24 and 36 months after the operation. The mean observation time was 20 months. At baseline, CDVA was 0.5 or better in 65% of the eyes; this improved to 0.5 or better in all eyes (0.8 or better in 79%) at the end of the observation. The mean baseline IOP was 17.1 mm Hg, which fell to a mean of 15.1 mm Hg. The mean number of medicinal eye drops prescribed preoperatively was 1.7, which decreased to 0.26 at the end of the observation. Cataract surgery combined with iStent implantation seems to be an effective procedure in patients with mild to moderate open-angle glaucoma and cataracts. The insertion of 1 stent resulted in a significant decrease in IOP and a reduction in the number of topical anti-glaucoma medications needed. Based on the characteristics of the observed complications, iStent implantation can be considered a safe method.

Ab externo device for the treatment of glaucoma: direct flow from the anterior chamber to the ocular surface.

A new microinvasive glaucoma surgery device, the Beacon Aqueous Microshunt (BAM), drains aqueous humor directly from the anterior chamber to the surface of the eye vs draining to enclosed spaces within the eye, where outflow resistance, including the episcleral venous pressure, might limit drainage effectiveness. The BAM has a 0.030 mm × 0.048 mm channel and provides a fixed resistance. For implantation, a 1.40 mm wide transcorneal incision into the anterior chamber was created with a posterolimbal outer placement under topical anesthesia. The surgery was easy to execute and had a flat learning curve. Preliminary and early experience have shown success with lowering intraocular pressure immediately postoperatively. In conclusion, the BAM offers a promising minimally invasive surgical procedure.

Outflow Facility Effects of 3 Schlemm’s Canal Microinvasive Glaucoma Surgery Devices

To study the effect of 3 Schlemm's canal (SC) microinvasive glaucoma surgery (MIGS) devices on outflow facility. Paired comparisons, randomized design, baseline-controlled study. Thirty-six pairs of dissected anterior segments from donated human eye bank eyes without glaucoma were studied. A baseline measurement was collected from each eye to serve as its control. Using a constant pressure perfusion method, outflow facility was measured in paired eyes from human donors. Measurements were made at perfusion pressures of 10 mmHg, 20 mmHg, 30 mmHg, and 40 mmHg. Outflow facility was measured before (baseline control) and after the implantation of an SC glaucoma drainage device or sham procedure. Three sets of experiments were carried out comparing 1 and 2 iStent Trabecular Micro-Bypass Stents and 2 iStent Inject implants with the Hydrus Microstent. Change in outflow facility from baseline or contralateral eye. After Hydrus placement, the outflow facility increased from 0.23±0.03 μl/minute per millimeter of mercury at baseline to 0.38±0.03 μl/minute per millimeter of mercury (P < 0.001). The percent increase in outflow facility was 79±21% for the Hydrus and 11±16% for the 2 iStent Inject devices, a difference that was significant (P= 0.018). Outflow facility with 1 iStent (0.38±0.07 μl/minute per millimeter of mercury) was greater than baseline (0.28±0.03 μl/minute per millimeter of mercury; P= 0.031). The 1 iStent showed a greater increase in outflow facility from baseline (0.10±0.04 μl/minute per millimeter of mercury) compared with the sham procedure (-0.08±0.05 μl/minute per millimeter of mercury; P= 0.042). No other significant differences were found. The longer the MIGS device, and thus the more SC that it dilates, the greater the outflow facility.

The Cost and Economics of Endoscopic Cyclophotocoagulation in the United Kingdom: A Tertiary Center Experience.

As the only microinvasive glaucoma surgery (MIGS) with a reusable component, the cost per procedure of endoscopic cyclophotocoagulation (ECP) diminishes with each successive use. We present a cost comparison of ECP with other MIGS devices, based on our clinical practice. ECP delivers diode laser via a reusable probe to the ciliary processes under direct visualization. The aim of our study is to evaluate the direct cost of ECP based on a retrospective review of cases and compare the cost per procedure with other MIGS devices. We conducted a retrospective review of ECP procedures performed at St Thomas' Hospital over 4.5 years. The cost of the ECP endoscope and diode laser consoles, reusable probes, and maintenance contracts were obtained from the hospital procurement log. The on-site Central Sterile Services Department was contacted for probe sterilization and repackaging costs. The cost per device for ECP and commonly performed MIGS procedures were obtained from the product specialists of each company. A total of 332 procedures were performed using 37 ECP probes during the study period. Each reusable ECP laser probe was found to give an average of 8.97 laser treatments. The cost per procedure decreased over the course of 4.5 years from £819.43 for the first 42 cases to £341.50 after 332 cases. Compared with other MIGS devices, the cost per procedure of ECP after 100 procedures is second lowest to the Kahook Dual Blade and reduces with each successive procedure performed. The ability to reuse each ECP probe significantly lowers the cost per procedure compared with other MIGS devices in the United Kingdom. The cost per procedure continues to reduce with each successive procedure.

Combined phacoemulsification and microinvasive glaucoma surgery in comparison to phacoemulsification alone for open angle glaucoma.

Microinvasive glaucoma surgery (MIGS) combined with phacoemulsification is increasingly utilised in glaucoma management. To describe the postoperative outcomes of phacoemulsification alone compared to combined phacoemulsification and iStent (Glaukos, San Clemente, CA) or Hydrus (Ivantis, Irvine, CA) for open angle glaucoma. Retrospective single surgeon comparative case series in a private practice setting. A total of 297 eyes in 190 patients (M:F = 85:105) were included consecutively from March 2011 to June 2017 with the data analysed using linear mixed models. Main outcome measures were intraocular pressure(IOP) and number of medications. By 6 months, all groups showed a reduction in IOP, with the combined iStent group by 4.2 mm Hg and the combined Hydrus group by 4.5 mm Hg, and this trend was sustained with follow-up to two years. All groups also showed a reduction in number of medications, with the phacoemulsification alone cases by 0.3, the combined iStent group by 0.7 and the combined Hydrus group by 1.1 medications. Both the combined surgeries had sustained reduction of number of medications with follow-up to 2 years. Postoperative complications from MIGS device insertion were uncommon and all resolved by one month. The combination of phacoemulsification and a MIGS device in open angle glaucoma patients reduced the intraocular pressure and the number of medications by the first postoperative month and had longer-term effects at 2 years follow-up. If the device is inserted without intraoperative complication, the rate of significant short-term risks are low.

A Prospective Randomized Trial Comparing Hydrus and iStent Microinvasive Glaucoma Surgery Implants for Standalone Treatment of Open-Angle Glaucoma: The COMPARE Study

To compare the efficacy of different microinvasive glaucoma surgery (MIGS) devices for reducing intraocular pressure (IOP) and medications in open-angle glaucoma (OAG). Prospective, multicenter, randomized clinical trial. One hundred fifty-two eyes from 152 patients aged 45 to 84 years with OAG, Shaffer angle grade III-IV, best-corrected visual acuity (BCVA) 20/30 or better, and IOP 23 to 39 mmHg after washout of all hypotensive medications. Eyes with secondary glaucoma other than pseudoexfoliative or pigmentary glaucoma, angle closure, previous incisional glaucoma surgery, or any significant ocular pathology other than glaucoma were excluded. Study eyes were randomized 1:1 to standalone MIGS consisting of either 1 Hydrus Microstent (Ivantis, Inc, Irvine, CA) or 2 iStent Trabecular Micro Bypass devices (Glaukos Inc, San Clemente, CA). Follow-up was performed 1 day, 1 week, and 1, 3, 6, and 12 months postoperatively. Within-group and between-group differences in IOP and medications at 12 months and complete surgical success defined as freedom from repeat glaucoma surgery, IOP 18 mmHg or less, and no glaucoma medications. Safety measures included the frequency of surgical complications, changes in visual acuity, slit-lamp findings, and adverse events. Study groups were well matched for baseline demographics, glaucoma status, medication use, and baseline IOP. Twelve-month follow-up was completed in 148 of 152 randomized subjects (97.3%). At 12 months, the Hydrus had a greater rate of complete surgical success (P < 0.001) and reduced medication use (difference= -0.6 medications, P= 0.004). More Hydrus subjects were medication free at 12 months (difference= 22.6% P= 0.0057). Secondary glaucoma surgery was performed in 2 eyes in the 2-iStent group (3.9%) and in none of the Hydrus eyes. Two eyes in the Hydrus group and 1 in the 2-iStent group had BCVA loss of ≥2 lines. Standalone MIGS in OAG with the Hydrus resulted in a higher surgical success rate andfewermedications compared with the 2-iStent procedure. The 2 MIGS devices have similar safety profiles.

Systematic Literature Review of Clinical and Economic Outcomes of Micro-Invasive Glaucoma Surgery (MIGS) in Primary Open-Angle Glaucoma.

IntroductionPrimary open-angle glaucoma is estimated to affect 3% of the population aged 40–80 years. Trabeculectomy is considered the gold standard in surgical management of glaucoma; however, it is a technically complex procedure that may result in a range of adverse outcomes. Device-augmented, minimally invasive procedures (micro-invasive glaucoma surgeries, MIGS) have been developed aiming for safer and less invasive intraocular pressure (IOP) reduction compared with traditional surgery.MethodsThis paper presents results from a systematic literature review conducted in accordance with National Institute for Health and Care Excellence requirements for the Medical Technology Evaluation Programme via multiple databases from 2005 to 2016. For clinical outcomes, randomized clinical trials (RCTs) comparing MIGS with trabeculectomy or other therapies, observational studies, and other non-RCTs were included. Clinical outcomes reviewed were the change from baseline in mean IOP levels and change in topical glaucoma medication. Safety was assessed by reported harm and adverse events. For economic evidence, trials on cost-effectiveness, cost-utility, cost-benefit, cost-consequences, cost-minimization, cost of illness, and specific procedure costs were included. Risk of bias was assessed for clinical studies using the Cochrane Risk of Bias tool.ResultsA total of nine RCTs (seven iStents®, one Hydrus®, and one CyPass®), seven non-RCTs (three iStent®, three CyPass®, and one Hydrus®), and 23 economic studies were analyzed. While various forms of trabeculectomy can achieve postoperative IOP of between 11.0 and 13.0 mmHg, MIGS devices described in this review were typically associated with higher postoperative IOP levels. In addition, MIGS devices may result in increased hypotony rates or bleb needling in subconjunctival placed devices, requiring additional medical resources to manage. There is limited available evidence on the cost-effectiveness of MIGS and therefore it remains unclear whether the cost of using MIGS is outweighed by cost savings through decreased medication and need for further interventions.ConclusionLarger randomized trials and real-world observational studies are needed for MIGS devices to better assess clinical and economic effectiveness. Given the shortage of published data and increasing use of such procedures, living systematic reviews may help to provide ongoing and timely evidence-based direction for clinicians and decision makers. This review highlights the current unmet need for treatments that are easy to implement and reduce long-term IOP levels without increasing postoperative aftercare and cost.FundingSanten GmbH, Germany.Electronic supplementary materialThe online version of this article (10.1007/s40123-018-0131-0) contains supplementary material, which is available to authorized users.

Gel Stent Implantation—Recommendations for Preoperative Assessment, Surgical Technique, and Postoperative Management

The surgical management of glaucoma offers the potential to lower intraocular pressure (IOP) independent of patients’ compliance with their medication regimen. Procedures such as trabeculectomy and tube shunt placement often yield large magnitudes of IOP reduction, but may be associated with short- and long-term complications. Microinvasive glaucoma surgery (MIGS) offers an alternative surgical approach that is inherently less invasive; however, most devices that fit in this category are associated with a lesser degree of IOP-lowering efficacy compared with traditional glaucoma surgeries. A newer MIGS device, a gel stent that facilitates drainage to the subconjunctival space, appears to offer similar IOP reduction to trabeculectomy, but with much less tissue manipulation; better predictability; and less sight-threatening complications, thus making it a potentially safer and more predictable surgical option in appropriate patients. The following proposed protocol, based on evidence-based practices and augmented where necessary by the opinions of experienced surgeons, provides guidance for the pre-, intra-, and postoperative management of patients receiving a gel stent implant. The goal of this protocol is to provide a framework for better patient selection and preparation, surgical pearls, and how best to assess and manage patients in the postoperative period.

Safety and Efficacy of Microinvasive Glaucoma Surgery.

Microinvasive glaucoma surgery (MIGS) is emerging as a new therapeutic option for glaucoma patients who wish to reduce their medication burden and avoid the postoperative complications of conventional glaucoma filtration surgery. These devices differ in terms of their efficacy and safety profile. Schlemm's canal devices have the most favorable safety profile at the compromise of modest efficacy, while subconjunctival and suprachoroidal devices are potentially more effective at lowering the intraocular pressure at the expense of a higher rate of complications. This review consolidates the latest evidence on the efficacy and safety of the MIGS devices in clinical use and provides an overview on upcoming devices which would likely also become viable treatment options in the near future. These clinical data would assist a glaucoma surgeon in selecting the most appropriate MIGS device for each patient based on the glaucoma severity and patient expectations.