Angle stability and outflow in dual blade ab interno trabeculectomy with active versus passive chamber management

Abstract

PurposeTo compare intraoperative angle stability and postoperative outflow of two ab interno trabeculectomy devices that excise the trabecular meshwork with or without active aspiration and irrigation. We hypothesized that anterior segment optical coherence tomography (AS-OCT) allows for a quantitative comparison of intraoperative angle stability in a microincisional glaucoma surgery (MIGS) pig eye training model.MethodsTwelve freshly enucleated porcine eyes were measured with AS-OCT at baseline, at the beginning of the procedure and at its conclusion to determine the anterior chamber depth (ACD) and the nasal angle α in degrees. The right and left eye of pairs were randomly assigned to an active dual blade goniectome (aDBG) and a passive dual blade goniectome (pDBG) group, respectively. The aDBG had irrigation and aspiration ports while the pDBG required surgery under viscoelastic. We performed the procedures using our MIGS training system with a standard, motorized ophthalmic operating microscope. We estimated outflow by obtaining canalograms with fluorescent spheres.ResultsIn aDBG, the nasal angle remained wide open during the procedure at above 90° and did not change towards the end (100±10%, p = 0.9). In contrast, in pDBG, ACD decreased by 51±19% to 21% below baseline (p<0.01) while the angle progressively narrowed by 40±12% (p<0.001). Canalograms showed a similar extent of access to the outflow tract with the aDBG and the pDBG (p = 0.513). The average increase for the aDBG in the superonasal and inferonasal quadrants was between 27 to 31% and for the pDBG between 15 to 18%.ConclusionAS-OCT demonstrated that active irrigation and aspiration improved anterior chamber maintenance and ease of handling with the aDBG in this MIGS training model. The immediate postoperative outflow was equally good with both devices.

Outflow Enhancement by Three Different ab Interno Trabeculectomy Procedures in a Porcine Anterior Segment Model

“…Either removing [25,26] or bypassing [21,27] these tissues can lead to a reduction in IOP. In our previous study, we characterized an ab interno goniotomy device with an active irrigation and aspiration and found that the anterior chamber depth and the nasal angle remained steady throughout the entire procedure, in contrast to a significantly lower anterior chamber stability in a passive dual blade goniotomy [12]. In the current study, we investigated the IOP-lowering efficacy of the same newly developed device in a porcine eye perfusion model and compared its performance with a plasma-mediated ablation and a passive dual blade.…”

“…The anterior segment perfusion culture followed our previous protocols [12,18,19]. Briefly, within two hours of sacrifice, fresh pig eyes from a local slaughterhouse were sterilized with 5% Betadine and subsequently bisected.…”

“…The Goniotome (Neomedix, Tustin, CA, USA) is a new device that combines elements of both K and T. Like K, G consists of dual blades that cut into the TM tissue but they are serrated to initiate a double cut more reliably. However, like T, G involves an active irrigation and aspiration to control the stability of the anterior chamber without the need for viscoelastic material [11,12]. Although separate studies have assessed and confirmed the efficacy of T and K, no study to date has evaluated G or performed a comprehensive comparison of the three techniques.…”

“…Although separate studies have assessed and confirmed the efficacy of T and K, no study to date has evaluated G or performed a comprehensive comparison of the three techniques. In the past, outflow tracers were the primary method of examining flow [12][13][14][15][16] and the impact on the outflow facility was not assessed. The purpose of this study was to compare the increase of outflow facility in a porcine perfusion model by each.…”

Two-Year Outcomes of Ab Interno Trabeculectomy with the Trabectome for Chinese Primary Open Angle Glaucoma: A Retrospective Multicenter Study

“…The Trabectome provides active irrigation and aspiration, which maintains better stability and temperature in the anterior chamber, compared with passive chamber management [18]. No hypotony or bleb-related complications occur [10,11,19,20].…”