Ab interno tube ligation for refractory hypotony following non-valved glaucoma drainage device implantation

Abstract

Purpose To report the 2-year outcomes of a novel surgical technique allowing reduction of the intraluminal diameter of the tube without total tube occlusion in order to allow enough increase in outflow resistance to permit resolution of hypotony whilst also achieving adequate IOP control. Methods This was a single-surgeon retrospective case note review of all non-valved GDD cases over an 8-year period (2008-2015) that underwent ab interno ligation of the drainage tube in order to manage post-operative hypotony (Baerveldt or Molteno). Twelve eyes of 12 patients (4.4%) developing refractory hypotony that did not respond to multiple intracameral ophthalmic viscoelastic device (OVD) injections were included in this retrospective case series and were treated with our ab interno tube ligation technique. The post-ligation management algorithm consisted of reinstating topical anti-glaucoma agents, laser suture lysis (LSL), or further ab interno ligation.

Insertion of a Preserflo microshunt inside a non-valved glaucoma shunt to treat late-onset hypotony

“…[ 12 13 ] However, late-onset hypotony is much less common, with reported rates of up to 13%. [ 14 15 ] Previous attempts in our case to use more traditional methods of hypotony treatment were unsuccessful; specifically, insertion of an 8 mm 3-0 Prolene suture led to high pressures, and a 4-0 Prolene suture led to persistent hypotony. Significant variability of the IOP is not uncommon in these advanced glaucomatous eyes.…”

Analytical model for managing hypotony after implantation surgery of a glaucoma drainage device

“…Hypotony can also occur with Ahmed valved devices despite the valve mechanism. For this reason, glaucoma surgeons have proposed to introduce a suture inside the lumen of these implants to increase the IOP (Lim and Hwang 2018 ; Song and Hwang 2020 ; Pollmann et al 2020 ; Vergados et al 2019 ; Chen 2017 ; Mavrommatis et al 2019 ; Rietveld and van-der Veen 2004 ). Although this intervention may be a good surgical maneuver, there is no standard indication about which suture diameter should be used as a function of the IOP before and after the implant surgery and the diameter and length of the drainage device.…”

Commentary: Meeting the nemesis of a non-valved glaucoma drainage device head-on

“…However, once the occlusive ligature autolyzes at around 5–6 weeks, during which a thin plate capsule formation occurs providing resistance to aqueous outflow, there remains a small risk of hypotony thereafter, of 0% to 4.4%. [ 1 2 ] Though rare, the consequences of this persistent hypotony can be devastating with shallow anterior chamber (AC), choroidal effusion, hypotony maculopathy and decrease in vision, which may become permanent if prompt management is not instituted. This late hypotony can at times be very difficult to manage, and strategies include either filling up the chamber with one or several injection/s of ophthalmic visco-surgical devices or even C 3 F 8 gas, or by manipulating the tube with secondary external ligatures or intra-luminal stenting.…”