SPS-404 Minimally Invasive Glaucoma Surgery: Surgical Outcomes and Comparisons | ASCRS
2020 ASCRS Virtual Annual Meeting

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Papers in this Session
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Clinical Outcomes of a Transscleral Gel Stent: Ab Interno Vs Ab Externo Stent Placement
Authors
Nathan M. Radcliffe, MD, ABO
Joseph F. Panarelli, MD
Tony P. Terraciano, MA

Purpose
Purpose/Relevance: Investigate surgical success rate, IOP reduction, medication reduction and bleb needle revision rate of a single surgeon’s initial trans-scleral gel stent (Xen 45, Allergan) placements performed through either an ab interno (AI) vs ab externo (AE) technique.

Methods
This is a retrospective comparative case series in a refractory glaucoma patient population in New York City. A single surgeon who performed a trans-scleral gel stent technique using an ab interno (AI) technique for over one year before changing the technique to an ab externo (AE) approach. After IRB approval, patient medical records were reviewed for baseline demographics, surgical technique, IOP, medication use, needle revision rate, and need for subsequent surgical intervention. Patients were included if the trans-scleral stent was performed as a standalone procedure or with cataract surgery and if at least 3 months of follow up information was available.

Results
Baseline IOP was 23.86 mm Hg on 2.58 meds for the AI group (n=57) vs 26.0 mm Hg on 3.1 medications for the AI group (n=25, p=>0.2). At month 3, mean IOP was 17.7 mm Hg on 1.5 medications for the AI group vs 18.2 mm Hg on 1.2 medications for the AE group (p>0.4). For AI, 61% of patients achieved a 20% IOP reduction at 3 months vs 76% of AE patients achieving a 20% IOP reduction. Revision of the bleb was performed in 22/57 (39%) of AI patients compared to 7/25 (28%) of AE patients. Secondary glaucoma surgery other than bleb needle revision (e.g., tube shunt) was performed in 8 of 57 AE patients (14.0%) vs 1 of 25 (4%) of AE patients. There was an extruded stent in an AI patient.

Conclusion
The trans-scleral gel stent, performed AI or AE, reliably reduced IOP in a refractory glaucoma patient population. IOP reduction, proportion of patients achieving 20% IOP reduction, med reduction, bleb revision and surgical reoperation rates favored the AE group. Both techniques exhibited excellent safety results.
Development of a Novel Near-Infrared Device to Detect Aqueous Draining Veins in the Sclera with the Goal of Improving the Efficacy of MIGS
Author
Mark C. Lobanoff, MD, ABO

Purpose
MIGS devices work best when placed in the trabecular meshwork and close to scleral aqueous draining veins. These veins are not visible with a surgical microscope. Hemoglobin absorbs near-infrared light more than sclera or skin tissue. Can a device be built that can use near-infrared (NIR) light to locate the location of aqueous draining veins?

Methods
Devices currently exist in phelobotomy that use near-infrared light to detect veins beneath the skin, analyze their location, and then display a high definition illuminated map on the skin showing their location. Using a NIR camera and an intense NIR LED light source, the veins and trabecular meshwork are located. Images are sent to the computer for processing then in real time an image of all structures is displayed on the eye at the operating scope. We plan to show: Projected visualization of the venous scleral plexus Visualization of the trabecular meshwork Visualization of aqueous flow and the increase in flow after placement of MIGS.

Results
Images of the anterior segment of the eye from the device showing the detection of scleral aqueous draining veins will be shown. Detection of the trabecular meshwork amidst the angle structures using the device will be shown. We may have in-situ images showing the change in flow rates in the aqueous draining vessels after implantation of a MIGS device.

Conclusion
MIGS devices are limited in their efficacy if not placed in the trabecular meshwork and if placed in areas of the eye that lack draining aqueous veins. A NIR visualization system that can identify these features for the surgeon and detect the efficacy of a MIGS device prior to leaving the OR would greatly improve the success of MIGS devices.
A First-in-Human Study of the Efficacy and Safety of a Supraciliary Glaucoma Drainage Device in Patients with Open Angle Glaucoma
Authors
Ike K. Ahmed, MD, FRCSC
Philippe Denis, MD, PhD
Christoph W. Hirneiss, MD, PhD
Prasad K. Reddy, MD
Anita C. Kamarthy, MD
Ernesto A. Calvo, MD, ABO
Zubair Hussain, PhD

Methods
In a prospective, multicenter, interventional, single-arm trial (STAR-I), 25 eyes were successfully implanted with a 5mm long supraciliary device in a stand-alone, ab interno procedure. The device is made of biocompatible STAR material which is soft and flexible silicone in a micro-porous network design. Intraocular pressure (IOP), medication use, and other ocular parameters were evaluated preoperatively and postoperatively through 18 months, at pre-specified timepoints. The primary endpoint of the study is IOP reduction at 6 months compared to baseline analyzed with a paired t-test. Safety evaluation included the nature and frequency of adverse events. The 18-month results are reported here

Results
Baseline mean diurnal IOP (standard error[SE]) was 23.1(0.6)mmHg using 2.0±1.1 IOP-lowering medication ingredients (mean±standard deviation[SD]). At 6-month follow-up, mean diurnal IOP was reduced by 9.0mmHg or 39% from baseline (p<0.0001), and the number of medication ingredients was 0.3±0.7 (mean±SD). At 18-month follow-up, mean(SE) diurnal IOP was 14.7(0.7)mmHg, a mean reduction of 8.5mmHg or 36% from baseline, using 0.7±1.1 (mean±SD) medication ingredients. Furthermore, of 22 patients completing 18-month follow-up, 14 (64%) were medication-free and 20 (90%) achieved an IOP reduction of ≥20% from baseline. No serious ocular adverse events or additional glaucoma surgery were reported.

Conclusion
This supraciliary MIGS device implanted in a standalone procedure was shown to be a powerful treatment option to reduce IOP and eliminate the need for medication in a majority of patients with open-angle glaucoma up to 18 months post-implantation, without causing serious ocular adverse events. Final results at 24 months are forthcoming.
Trabecular Micro-Bypass Stent Implantation Combined with Cataract Surgery after Previous Glaucoma Filtering Surgery: 36 Months Outcomes.
Authors
Rodolpho T. Matsumoto, MD
Ali Salimi, MSc
Paul J. Harasymowycz, MD

Purpose
To investigate the three-year outcomes related to cataract surgery with concomitant implantation of two first or second generation trabecular micro-bypass stents (CS-TMS) in eyes with previous filtering glaucoma surgery.

Methods
In this retrospective case series, phakic eyes with previous filtering surgery that underwent CS-TMS for further IOP or medication reduction were included. Qualified success was defined as an intraocular pressure (IOP) of ≤ 18 mmHg, no increase in number of glaucoma medications, and absence of further glaucoma surgeries or loss of light perception. Changes in IOP, medication burden, and best-corrected visual acuity (BCVA) were assessed using General Linear Models with significance at p<0.05.

Results
29 eyes, 11 with prior trabeculectomy (Trab) and 18 with deep sclerectomy (DS), with a mean age of 64.9±10.9 were included. The 3-year qualified success for the whole cohort was 75% with no significant difference between the Trab (70%) and DS (77%) groups (p=0.570). CS-TMS led to a significant decrease in IOP from 17.1±4.8 mmHg to 13.1±2.3 (23% reduction, p<0.001) as well as medication score from 2.9±1.0 to 2.2±1.3 (25% decrease, p=0.006), with no significant time-group interaction for either outcome. BCVA remained stable (p>0.05) and the post-operative complications were few and included microhyphema, peripheral anterior synechiae, and intra-ocular lens dislocation, each in one eye.

Conclusion
Data on efficacy of trabecular micro-bypass stents in eyes with previous filtering surgery is limited. Our results highlight that CS-TMS is a safe treatment option with remarkably good medium-term outcomes in this population as demonstrated by significant reductions in IOP and medication burden and transient and non-sight threatening complications.
Prospective Safety and Efficacy Evaluation of Bent Ab-Interno Needle Goniectomy (BANG); A MIGS Option for the Developing World
Authors
Igor Bussel, MD, MHA
Richard Schroeder, MD
Arsham Sheybani, MD, ABO

Purpose
To introduce a simple and low-cost minimally invasive glaucoma surgery (MIGS) and to report the preliminary results. We will present the initial safety and efficacy data on Bent Ab-interno Needle Goniectomy (BANG) and propose that this procedure is an option in developing countries.

Methods
Study design: prospective, non-randomized, non-comparative, interventional case series. Inclusion criteria: adults with glaucoma and coexistent visually significant cataract who underwent phacoemulsification with intraocular lens placement with BANG at an academic medical center between July 2018 and June 2019. Intervention: Bent Ab-interno Needle Goniectomy (BANG) uses a bent 27-gauge needle (average cost < $1) to excise trabecular meshwork tissue under gonioscopic visualization without the need for proprietary devices, units, or materials. Outcome measures: intraocular pressure (IOP), glaucoma medications, degree of meshwork removal, intraoperative and post-operative complications.

Results
Thirty two eyes with an age range of 31 to 81 (average 66.9) years underwent phaco/IOL + BANG. The types of glaucoma were as follows: 15 POAG, 2 JOAG, 1 PXF, 9 PACG, 2 PAC, 2 Uveitic, and 1 OHTN. The average IOP maximum was 24.7 mm Hg and the average pre-operative IOP was 19.69 +/- 4.92 (SD) mm Hg on 1.66 +/- 1.15 (SD) medications. At post-operative month 3, the average IOP was 13.92 +/- 1.89 (SD) mm Hg on 0.38 +/- 0.77 (SD) medications. The 29% decrease in IOP and 77% decrease in medications (about 1 medication) were both statistically significant changes (p<0.001). An average of 97.6 degrees of trabecular meshwork was excised (range 75 to 120 degrees).

Conclusion
The safety and efficacy of BANG preliminary results are promising and at least equivalent to other proprietary MIGS procedures. This suggests that BANG can be used as simple and low-cost MIGS option in the developing world where resources are limited. BANG can be readily taught, adopted, and combined with existing cataract surgery missions.
Novel Technique for Treatment and Evaluation of Open-Angle Glaucoma: Ab Interno Canaloplasty Combined with In Vivotrypan Blue Venography.
Authors
Derek M Waldner, PhD
Patrick Gooi, MD
Gavin S. Docherty, FRCSC
Matthew B. Schlenker, MD, FRCSC
Bryce A. Ford, MD
Andrew C. Crichton, FRCSC
Ike K. Ahmed, MD, FRCSC

Purpose
To demonstrate a new minimally invasive glaucoma surgical technique to lower intraocular pressure and simultaneously visualize the aqueous outflow pathway.

Methods
Trypan blue is injected into a Healon ophthalmic viscoelastic cartridge via a one inch-25 gauge needle. The Trypan blue is then mixed into the Healon. A 2.2mm clear corneal incision is then made temporally followed by a paracentesis. Healon 5 is used to inflate the anterior chamber. A 25-gauge needle is used to create a nasal goniotomy. The iTrack (iScience Interventional, Menlo Park, CA), attached to a screw-driven syringe, is inserted into the goniotomy and advanced through Schlemm’s canal. At the surgeon’s discretion a one-eighth turn of the syringe injects a small amount of trypan-viscoelastic mixture into Schlemm’s canal. The trypan allows visualization of episcleral vein patency.

Results
The authors are evaluating the safety and efficacy of this technique and data collection is ongoing. Currently there have been no complications and intraocular pressure lowering is equivalent to previously described iTrack canaloplasty. The post-trabecular outflow pathways identified in this technique showed diffuse as well as segmental patterns. Also, the caliber of the episcleral veins identified varied from barely detectable to a prominent venographic pattern.

Conclusion
This technique may allow us to further our understanding of the aqueous outflow system and its role in the underlying pathophysiology of glaucoma. It may be used in conjunction with any angle surgery procedure that enhances outflow via Schlemm’s canal. Further research is required to evaluate the prognostic significance of this technique.
Ocular Surface Disease Improvement in Eyes Implanted with Trabecular Meshwork Bypass Stents (iStent or iStent inject)
Authors
Brandon J. Baartman, MD
John P. Berdahl, MD
Whitney Hauser, OD
Mitch J. Ibach, OD
Justin A. Schweitzer, OD

Methods
A prospective trial was conducted across two sites. 50 patients underwent cataract surgery in combination with iStent or iStent inject trabecular meshwork bypass stent(s). Key data collected pre- and postoperatively include: number of glaucoma medications, number of ocular surface disease medications, artificial tear usage, intraocular pressure (IOP), Ocular Surface Disease Index (OSDI), corneal/conjunctival staining (Oxford Grading Scale), fluorescein tear break-up time (FTBUT) and conjunctival hyperemia (Efron Scale). While subjects were followed-up 1 day, 1 month, 1 week, 1 month and 3 months post-operatively as usual , the OSD evaluation was only conducted at the 3-month visit

Results
All patients were successfully implanted with either iStent or iStent inject with no intra- or postoperative complications with an overall good safety profile. At 3 months OSDI improved from 41.7±21.8 (severe) preoperatively to 18.3 ± 15.6 (mild); FTBUT improved from 4.3±2.2 seconds to 6.4±2.5 seconds; corneal/conjunctival staining (Oxford Grading Scale) improved from 1.4±0.98 to 0.4±0.59, conjunctival hyperemia (Efron Scale) improved from 1.4 to 1.2 (all p<0.001 except Efron). A significant reduction in both the number of glaucoma medications and IOP was demonstrated (1.5±0.8 medications preop to 0.6±0.8; 17.4±4.2 mmHg to 14.5±3.2 mmHg (p<0.001 for both)).

Conclusion
This study provides the first set of evidence showing benefits to the ocular surface with combined cataract surgery and iStent or iStent inject trabecular bypass stent(s). An improvement in ocular surface disease was demonstrated. Consistent with current literature, a reduction in IOP and medication was shown with iStent and iStent inject
Results of Subconjunctival MIGS Gel Stent Implantation at the Time of Cataract Surgery Versus Stand Alone Procedure
Author
Eva I. Liang, MD, FACS, ABO

Purpose
To compare real-world clinical results of a gel stent for subconjunctival minimally invasive glaucoma surgery (MIGS) as a combined procedure with cataract surgery versus a stand alone procedure.

Methods
In this retrospective comparative study, 117 eyes with refractory glaucoma underwent implantation of a subconjunctival MIGS device (Xen 45 gel stent), either in combination with cataract extraction (group 1; 80 eyes) or as a standalone procedure (group 2; 37 eyes). Patients with atypical anatomy (i.e. conjunctival scarring, previous corneal grafts, etc.) were excluded. Outcome measures included intraocular pressure (IOP) and number of medications used to control IOP. Patients were followed at 1 day, 1 week, 2 weeks, and 1, 3, 6 and 12 months postoperatively.

Results
Preliminary findings show good efficacy and safety in both groups. In the combined MIGS gel stent/cataract surgery group, mean IOP decreased from 17.70±6.51 mmHg preoperatively to 14.8±3.72 mmHg (p=.003) at 12 months; the mean number of medications decreased from 2.85±0.88 to 1.36±1.50. In the stand alone group, which had more severe glaucoma at baseline, mean IOP decreased from 23.60±4.93 mmHg preoperatively to 15.32±4.33 mmHg (p < 0.001) and the mean number of medications decreased from 2.90±1.15 to 1.60 ±1.68 (p=.006) at 12 months. Additional analyses are planned.

Conclusion
Subconjunctival MIGS with the Xen gel stent safely and effectively reduces IOP and number of medications when performed in conjunction with cataract extraction in patients with refractory glaucoma, as well as in patients undergoing the stand alone procedure.
Comparison of Two Minimally Invasive Glaucoma Surgery Devices Targeting Trabecular Meshwork Outflow
Authors
William F. Wiley, MD
Kathleen J Jee, MD
Tanner J. Ferguson, MD
Shamik Bafna, MD

Purpose
To compare the safety and efficacy of two minimally invasive glaucoma surgery (MIGS) implants, the iStent trabecular micro-bypass device (Glaukos) and Hydrus microstent (Ivantis).

Methods
Retrospective, comparative case series at a single center comparing the first 100 consecutive cases of cataract surgery with either combined implantation of the iStent and endocyclophotocoagulation (ECP) or combined implantation of the Hydrus and ECP. Primary outcome measures included intraocular pressure (IOP) and number of glaucoma medications. Data was collected preoperatively and postoperatively at months 1 and 3. Safety profile was established by noting the need for additional surgery.

Results
Mean pre-operative IOP was 18.9 mmHg on 1.2 IOP-lowering medications for patients who underwent Hydrus and ECP, and 14.7 mmHg on 1.2 IOP-lowering medications for patients who underwent iStent and ECP. At post-operative month 1, mean IOP decreased to 14.6 mmHg in the Hydrus group compared to 14.3 mmHg in the iStent group. By post-operative month 3, mean IOP decreased to 14.2 mmHg on 0.7 IOP-lowering medications in the Hydrus group compared to 12.8 mmHg on 0.6 IOP-lowering medications in the iStent group. Data will be updated prior to presentation at the ASCRS 2020 meeting.

Conclusion
The results of this study suggest the Hydrus microstent may provide additional IOP-lowering compared to the iStent, and both appear to be safe and effective treatment options for patients with glaucoma at the time of cataract surgery.
Outcomes Following Implantation of an Anterior Segment Drainage Device (Xen45 Gel stent) Via an Ab-Interno or Ab-Externo Approach
Authors
Mark J. Gallardo, MD
Ahmad Kheirkhah, MD
Logan R Vincent, MD

Purpose
To evaluate and compare the early outcomes following Xen45 gel stent implantation either through an ab-interno (Xen) or trans-conjunctival ab-externo (Xen-Ex) approach and discuss therapeutic reductions in intraocular pressure and medication burden.

Methods
Single center consecutive case series of 200 patients with uncontrolled open angle glaucoma treated with the Xen45 gel implant as a stand-alone procedure (100 patients in each subgroup). Data was collected at 3, 6, 9, and 12 months (on-going data collection for Xen-Ex group). Primary endpoints were mean reduction in IOP and medication burden from baseline. Secondary end-points were those patients with an IOP < 15 mmHg and > 20% reduction from baseline without medications (complete success), IOP < 15 mmHg and >20% reduction from baseline requiring the same or fewer medications (qualified success) and those not meeting either forms of success (failure).

Results
A majority of the cohort was comprised of a demographically Hispanic patient population. Pre-operative mean IOPs were 23.5±7.0 and 24.4 ± 7.3 for the Xen and Xen-Ex groups, respectively. Mean preoperative medication burden was 3.3 ± 0.8 and 3.4 ± 0.9, respectively. IOPs reduced to 14.3±5.2 (6-months) and 13.3 ± 3.3 (12-months Xen group) with an associated drop in medications to 1.05±1.19 and 1.43±1.41. Mean IOP reduced in the Xen-Ex subgroup to 11.7 ± 3.7 (6-months) with associated drop in medications to 1.10±1.45. All time-points showed a statistically significant difference from baseline. 75% and 91% of subjects met secondary end-points for the Xen and Xen-Ex groups, respectively.

Conclusion
Implantation of the Xen45 gel implant is a safe and effective means for reducing IOP and medication burden in patients with uncontrolled OAG. The newly adopted method for implantation (Xen-Ex) appears to be as effective as the traditional method of implantation (ab-interno) in the early post-operative period. Longer-term follow-up is ongoing.
Three-Year Follow-up of Ab Interno Canaloplasty in Patients with Primary Open-Angle Glaucoma
Author
Mahmoud A. Khaimi, MD

Methods
This was an IRB-approved, retrospective analysis of 81 patients (106 eyes) who underwent ab interno canaloplasty either as a stand-alone treatment for glaucoma or in combination with cataract surgery. All surgeries were performed by the same surgeon (MK). The primary endpoints were a mean lowering of IOP and number of glaucoma medications, as well as the percentage reduction in IOP (between 12m and pre-op, between 24m and pre-op and between 36m and pre-op) and the percentage reduction in medications (between 12m and pre-op, between 24m and pre-op and between 36m and pre-op).

Results
The mean age of patients was 71 (range, 19-95), with 56% female and 44% male (N=45 and N=36, respectively). The mean pre-operative IOP of all eyes was 19.5 mm Hg. At the 36 months, it was 15.3 mm Hg (SD = 3.6). There was a statistically significant decrease in IOP across all visits when compared to baseline (p<0.001). 66 percent of eyes maintained a reduction in IOP from baseline at 36-months. Pre-operatively, the mean number of medications was 1.8 (SD=1, Min = 0, Max = 4). At 36-months, the mean number of medications was 0.67 (SD=0.77, Min = 0, Max = 3). Full results will be presented comparing outcomes between mild/moderate and severe glaucoma.

Conclusion
To the best of our knowledge, this is the first report of longer-term follow-up of POAG patients treated with ab interno canaloplasty. These results demonstrate that this approach is capable of achieving a sustained reduction in IOP and the number of medications out to 36-months and beyond.
The Effectiveness of Ab Interno Canaloplasty (iTrack) in the Treatment of Pigmentary and Pseudoexfoliation Glaucoma
Author
Mahmoud A. Khaimi, MD

Methods
A retrospective analysis of all pigmentary and psedoexfoliation (PEX) glaucoma patients treated with iTrack over the past 36 months by surgeons at Dean McGee Eye Institute. The evaluation included analysis of intraocular pressure (IOP), reduction in medications, changes in visual field, pachymetry and visual acuity.

Results
There were 31 eyes with PEX or pigmentary glaucoma included in this analysis. The mean age was 69.4 (SD=10.7), with a mean baseline IOP of 21.9 mm Hg (SD=9.8, Min = 11, Max= 55 mm Hg). 17 eyes (55%) had PEX glaucoma, with 14 eyes (45%) with pigmentary glaucoma. 74 percent of eyes had no history of surgery. Safety outcomes: there were no intra-operative complications with adverse events observed in 7 eyes (23%), which was defined as an IOP spike ≥30 mm Hg at 1-week post-op. Efficacy outcomes: At 24 months postoperative, there was a mean reduction in IOP of 3.7 mm Hg from baseline in 12 eyes (SD=9.7, Min=-9.7, Max=40 mm Hg), with a mean number of medications of 1.2 (SD=1, Min=0, Max=3).

Conclusion
Particularly in pigmentary glaucoma patient, who do not respond to laser treatment, the use of iTrack is a minimally invasive surgical treatment option that is safe and effective, providing an alternative to more invasive glaucoma procedures.

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