A New Method for Revision of Encapsulated Blebs after Trabeculectomy: Combination of Standard Bleb Needling with Transconjunctival Scleral Flap Sutures Prevents Early Postoperative Hypotony.

Panagiotis Laspas,Norbert Pfeiffer,Esther Maria Hoffmann,Alicia Poplawksi,Philipp David Culmann,Franz Hermann Grus,Verena Prokosch-Willing,Sanjoy Bhattacharya

doi:10.1371/journal.pone.0157320

Abstract

PurposeA simple needling procedure is the standard method for restoring the function of an encapsulated bleb after trabeculectomy. However, postoperative hypotony represents a possible hazard. This study describes a new surgical approach for treating encapsulated blebs with reduced risk of early postoperative hypotony: bleb needling combined with transconjunctival sutures tightening the scleral flap directly.MethodsThe study included two groups of 23 patients with failing bleb following trabeculectomy: “Group 1” underwent simple needling revision of the filtering bleb and served as a control group, while “Group 2” received needling revision with additional transconjunctival scleral flap sutures, if intraoperatively the intraocular pressure was estimated to be very low. Intraocular pressure (IOP), postoperative management and complications were analyzed over a follow-up period of 4 weeks postoperatively. Results were compared using t-test or Mann-Whitney U-tests.ResultsAdverse effects occurred with a higher frequency after sole needling of the bleb (5 cases of choroidal effusion and 1 case of choroidal hemorrhage) than after the combined method with additional scleral sutures (1 case of choroidal effusion). The IOP on the first postoperative day was significantly lower in group 1, with 9.43 ± 9.01 mm Hg vs. 16.43 ± 8.35 mm Hg in group 2 (P = 0.01). Ten patients with ocular hypotony (IOD of 5 mmHg or lower) were found in group 1 and only two in group 2. One week and one month after surgery the intraocular pressure was similar in both groups (P>0.05).ConclusionsThis new needling technique with additional transconjunctival scleral flap sutures appears to reduce postoperative hypotony, and may thus protect from further complications, such as subchoroidal hemorrhage.

Highlights

In order to prevent visual impairment in glaucoma, a reduction of intraocular pressure (IOP) through medication or surgery is mandatory
Adverse effects occurred with a higher frequency after sole needling of the bleb (5 cases of choroidal effusion and 1 case of choroidal hemorrhage) than after the combined method with additional scleral sutures (1 case of choroidal effusion)
In order to reduce the frequency of acute ocular hypotony and to prevent its possibly disastrous complications, we developed a technique of combining the needling procedure with additional transconjuctival scleral flap sutures to avoid overfiltration

Summary

Introduction

In order to prevent visual impairment in glaucoma, a reduction of intraocular pressure (IOP) through medication or surgery is mandatory. In cases with uncontrolled IOP despite medication, trabeculectomy remains the gold standard among surgical procedures that offer an adequate IOP reduction [1]. The introduction of antimetabolites as an adjunctive to trabeculectomy has improved the long–term outcome significantly [2,3,4], encapsulation of the filtration bleb with consecutive outflow disturbance and an increase in IOP remains the most common postoperative problem, occurring in around 13% of cases [5, 6]. A major complication of needling—with an incidence reported between 15– 30%—is postoperative hypotony [10, 11], especially if the scleral flap has to be lifted during the needling procedure. Late ocular hypotony may cause maculopathy, chorioretinal folds of the posterior pole, tortuosity of the retinal vessels and visual loss [12, 13]

Methods

Results

Conclusion