Intraluminal stenting versus external ligation of Ahmed glaucoma valve in prevention of postoperative hypotony

Abstract

AIM: To compare intraluminal stenting and external ligation of Ahmed glaucoma valves (AGV) for refractory glaucoma management and postoperative hypotony prevention. METHODS: This randomized prospective blind study included 30 eyes of 25 patients (age range: 44-56y) with refractory glaucoma. This study was conducted from September 2018 to January 2020. The study included two groups, AGV with intraluminal stenting group (n=15 eyes) and AGV with external ligation group (n=15 eyes). Follow-up period was one year postoperatively. The primary outcome was intraocular pressure (IOP) and its association with the number of postoperative glaucoma medications. IOP?≤?21 mm Hg without medications indicated complete success while IOP?≤?21 mm Hg with medications indicated qualified success; and IOP<6 mm Hg was defined as hypotony. RESULTS: After a year of follow-up, IOP was significantly reduced in the intraluminal stenting group than in the external ligation group (11.67±0.89 vs 14.2±4.0 mm Hg, respectively, P=0.024). Postoperative hypotony was more common in the external ligation group (2 cases, 13.33%) than in the intraluminal stenting group (1 case, 6.67%). CONCLUSION: Application of intraluminal stenting or external ligation during AGV surgery usually prevents postoperative hypotony (transient and persistent) that occurs in conventional AGV surgery.

Clinical outcomes of the PAUL® glaucoma implant: One‐year results

“…Different methods were proposed in order to prevent postoperative hypotony after GDD surgery: A common way to prevent early hypotony consists of placing an external ligature with a selfresorbing suture which is tied from outside around the tube. 17 Koh and colleagues described another modality for PGI surgery and named it 'PAUL Stability System'. They proposed a patch graft to cover the plate and inject an ophthalmic viscoelastic device (OVD) on top during surgery in order to reduce drainage over the plate.…”

“…A study by Abd Elfattah et al compared intraluminal suture stenting with external suture ligaturation in AGI, demonstrating that the former had better outcomes with regard to both mean IOP control (11.7 vs. 14.2 mmHg) and the risk of postoperative hypotony. 17 An external tube ligature can lead to an increased IOP in many cases during the early postoperative phase particularly if no Sherwood slit (also referred to as a 'blow valve') is used. 19 The commonest suture materials used are polyglactin (Vicryl), which is self-resorbing or nylon, which can be cut with YAG laser via direct or gonioscopic visualisation.…”

“…Even though the lumen of the PGI was reduced in comparison to the BGI, there remains a risk of early postoperative hypotony if no measures are being taken to avoid this from occurring. Different methods were proposed in order to prevent postoperative hypotony after GDD surgery: A common way to prevent early hypotony consists of placing an external ligature with a self‐resorbing suture which is tied from outside around the tube 17 …”

Chronic hypotony management using endoscopy-assisted vitrectomy after severe ocular trauma or vitrectomy

“…Second, cyclodialysis cleft or ciliary body detachment could increase the aqueous outflow. Third, ciliary body injury attributed to chemical or mechanical factors could result in reduced ciliary body secretion and increased aqueous uveoscleral outflow [16,[20][21] . In addition, some researchers have proposed that chronic traction of the AVS and aPVR could also result in hypotony [17][18] .…”