Education Committee Highlights WGC-2021 | part 1.2

Prevention and Management of Complications following Trabeculectomy

Conjunctival Leakage
Dr. Shamira Perera talked about how to recognize and manage intraoperative and postoperative conjunctival leaks. He stated that intraoperative leaks resulted from poor visualization and improper use of instruments. Dr Perrera showed cross stitch technique with 10-0 nylon and how closing in layers helped seal conjunctival buttonholes. He also spoke about limbus leakage, recommending the use of limbal mattress sutures for watertight limbus post-surgery.

He said that since conjunctival leaks predispose to bleb infections, utmost caution must be exercised. In cases with subtle conjunctival sweating, stress test can help identify the leak site. Bleb excision of unhealthy conjunctival tissue with tenon’s patching could help in cases with scleral defects. Conjunctival advancement, high forniceal conjunctival relaxing incisions or conjunctival autografting were other options for closure once the blow hole had been dealt with. For small blebs with small leaks, excessive conjunctiva could be pulled over the bleb area and sutured at the limbus.

Hypotony may be defined both statistically and clinically. Prof. Julian Garcia-Feijoo defined, classified, and discussed the causes of hypotony. He mentioned that the clinically relevant hypotony is much less than that reported in the literature. Identifying preoperative risk factors such as high myopia, was crucial in preventing postoperative hypotony. Not all cases of hypotony required treatment. Prof. Garcia-Feijoo suggested that the management of hypotony must be tailor made. Conservative management usually worked for most cases with early hypotony but surgical management was needed in all cases of late hypotony. His concluding remarks were to not focus on just the numerical value of intraocular pressure, but to address the anatomical and functional issues.

Dysfunctional Bleb
Dr. Masaru Inatani talked about when to choose between bleb needling and reoperation for a dysfunctional bleb. He stated that avascular blebs were ideal for needling because of ease of identification of the scleral flap and minimal risk of rebleeding and reobstruction. In cases where scleral flap was not visible due to thick scarred bleb, he recommended a Baerveldt Glaucoma drainage implantation. He showed videos of slit lamp bleb needling using a bent 25G needle and conjunctival autotransplantation in a case with bleb leakage. In another case with bleb rupture, bare sclera and flat anterior chamber, he showed bleb repair using the amniotic membrane transplantation.

Malignant Glaucoma
Dr. Jody Plitz Seymour discussed the inciting events, risk factors, mechanism of malignant glaucoma. Ultrasound biomicroscopy has established that the position of the lens-iris-diaphragm is the key for diagnosis. She presented a case of a hyperopic male with synechial angle closure, who underwent cataract surgery with goniosynechiolysis but postoperatively presented with a myopic shift and a malignant glaucoma. The patient responded to cycloplegic and antiglaucoma therapy. She discussed the role of inferior laser peripheral irido-capsule-hyaloidotomy in pseudophakic eyes with malignant glaucoma. Nearly 50 % cases required surgical intervention to achieve a unicameral eye. For cases with intraoperative malignant glaucoma, small core pars plana vitrectomy is ideal. She concluded that high risk eyes and fellow eyes needed extra attention to prevent the development of malignant glaucoma.

Dysesthetic Bleb
Large and overhanging filtering blebs cause foreign body sensation and a constant vague discomfort to patients. Dr. Tomas M Grippo described the risk factors and pathophysiology of developing bleb dysesthesia. He discussed the conservative as well as surgical management of dysesthetic blebs. Surgical techniques must be tailored as per the case. Dr Grippo said that for highly symptomatic blebs, surgical reduction was the only effective modality. Partial excision of the bleb with conjunctiva and tenon’s advancement worked in most cases while entire bleb excision with closing of the fistula and insertion of a drainage implant remains the final approach. He also described techniques which preserved bleb conjunctiva such as Compression sutures or the bleb windowpexy.

Blebitis and Endophthalmitis
Dr. Catherine Jui-Linh Liu talked about Bleb related infections (BRI) in terms of the staging formulated by the Collaborative Bleb-Relation Infection Incidence and Treatment Study (CBIITS) group. She stated that a high index of clinical suspicion was warranted as negative cultures were encountered in 21-86% of cases. Highly virulent organisms were more common in warm season while less virulent ones were common in winters. Treatment with Broad spectrum antibiotics must be initiated prompted until culture results become available. Dr. Jui-Linh Liu mentioned that as per the CBIITS, the risk of BRI was similar between limbus based and fornix based trabeculectomies. She talked about the preventive measures that could be taken pre and postoperatively to prevent BRIs.

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