JOCGP 10.5005/jp-journals-10008-1084 Bleb Revision
SURGICAL TECHNIQUE
Bleb Revision 1 1 2
Parul Ichhpujani, 2Surinder Singh Pandav
Assistant Professor, Department of Ophthalmology, Government Medical College and Hospital, Chandigarh, India
Additional Professor, Advanced Eye Center, Postgraduate Institute of Medical Education and Research, Chandigarh, India
Correspondence: Surinder Singh Pandav, Additional Professor, Advanced Eye Center, Postgraduate Institute of Medical Education and Research, Chandigarh, India, Phone: 91-172-2756116, Fax: 91-172-2747837, e-mail:
[email protected] ABSTRACT Trabeculectomy blebs may be problematic for more than one reason which may vary from a leak to scarring. Timely recognition of the signs and cause of bleb failure holds the key for successful outcome. Meticulous revision of the primary trabeculectomy can lead to resolution of bleb-related complications in most cases. Keywords: Bleb leak, Scarred bleb, Trabeculectomy.
INTRODUCTION Trabeculectomy is a commonly performed surgical procedure for lowering intraocular pressure. Although many trabeculectomies achieve successful outcomes, a minority develop bleb related complications. The term bleb revision encompasses variety of procedures that can be used in a host of clinical scenarios to salvage blebs. i. ii. iii. iv. v.
Five chief categories which warrant action include: Leaking bleb (postoperative or delayed) Hypotony maculopathy with an ischemic, nonleaking bleb Poorly functioning encapsulated bleb Intolerable dysesthesia Flat, scarred blebs.
Leaking Blebs A leaking bleb (Fig. 1) may lead to serious and even sightthreatening complications, such as flat anterior chamber, peripheral anterior synechiae, cataract, choroidal detachment, hypotony maculopathy and endophthalmitis.
Early If a bleb is leaking significantly, immediately postoperatively, it is closed on the same clinical day with a 10-0 Vicryl suture, or a nylon suture on a round bodied needle. Similarly, it is better to suture slight ooze that did not spontaneously resolve within a week.
Fig. 1: Leaking bleb
shields,3 rings,4 compression sutures,5,6 cryotherapy7 or laser to the bleb8,9 or intrableb autologous blood injection.10 Leaks have also been repaired with tissue adhesives11,12 or amniotic membrane grafts.13,14 External tamponade does not essentially alter the tissue architecture within the bleb, and therefore often is not effective in case of late leaks, chronic overfiltration and exuberant blebs. Surgical revision of the bleb is therefore a logical option.15 These delayed bleb leaks need to be treated aggressively. Prior to conjunctival advancement, it should be made sure that there is no element of blebitis.
Delayed
Hypotony Maculopathy with an Ischemic Nonleaking Bleb
Occasionally, blebs treated with mitomycin C or 5-fluorouracil become progressively thin, oversized and vulnerable, and therefore predisposed to delayed recurrent leaks.1 Focal bleb leaks, overfiltrating and symptomatic large blebs have been treated with aqueous suppressants and topical antibiotics, external tamponade with patches, bandage contact lenses,2
With the increased use of the antimetabolites, as an adjunct to trabeculectomy, hypotony maculopathy has become an increasingly common serious postoperative complication. The cause of hypotony after trabeculectomy can be associated with overfiltration, wound leak or reduced aqueous production, which may be related to inflammation.16
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Parul Ichhpujani, Surinder Singh Pandav
For nonleaking blebs, some surgeons have advocated leaving the avascular bleb tissue and pulling a new conjunctival flap over it while others prefer to excise the old bleb, because it allows assessment of the scleral flap which is often reinforced with additional 10-0 nylon sutures.17 Some surgeons advocate the use of a free conjunctival graft when there is inadequate conjunctiva to create a new bleb.18 A piece of donor sclera is useful to reinforce a gelatinous-appearing flap or full-thickness hole.
Encapsulated, Poorly Functioning Bleb The success of trabeculectomy may be short-lived owing to excessive wound healing and/or excessive cellular activity leading to scarring or encapsulation of the filtering bleb (Fig. 2), resulting in surgical failure. Repeat surgery has lesser success rate than the primary filtering surgery. Needling with injection 5-fluorouracil or transconjunctival mitomycin C can be considered for revising such a bleb.19-22
Fig. 2: An encapsulated bleb
Intolerable Dysesthesia Mostly, dysesthesia resolves with adequate lubrication and treatment of the underlying dry eye. Blebs are revised when lubricating therapy fails.23 Superior dysesthetic blebs that extend onto the cornea can be trimmed at the limbus, usually without cautery or suturing. Interpalpebral dysesthetic blebs, such as those that sit on the lid margin, can be shrunk with light cryotherapy (< 10 seconds) applied in rows to limit and reduce the interpalpebral extension of the bleb.
Flat, Scarred Blebs To determine if a bleb has failed, gonioscopic confirmation of a patent sclerectomy is done. Bleb function is evaluated and remaining potential is assessed by applying pressure 180° away while observing through the slit lamp. This test can be performed somewhat forcefully if no bleb forms with light massage. Alternatively, the Carlo E Traverso maneuver involves pushing directly adjacent to the side of the scleral flap with a blunt object, such as a scleral depressor or through the upper eyelid with a finger or cotton swab. If no bleb forms, then this is a flat bleb secondary to scarring. Needling procedure does not address the failed blebs due to subscleral scarring. On the other hand, repeat trabeculectomy is associated with anterior chamber handling associated complications. Our technique (Figs 3A to F) combines the advantages of addressing subscleral fibrosis with limited dissection and no or minimal handling of anterior chamber. After dissection of conjunctiva and Tenon’s capsule (about 7-8 mm from the limbus), blunt dissection into bleb area is done with the help of Westcotts’ scissors. Fibrous tissue overlyings conjunctiva and sclera is dissected, and the scleral flap is exposed. Mitomycin C (0.4%) soaked sponge is kept over the scleral flap. The scleral flap is identified with the help
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Figs 3A to F: Diagram of sequential steps in performing revision of a scarred filtering bleb: (A) Recognition of the flap landmarks in the scarred bleb, (B) dissection of conjunctiva and Tenon’s capsule, (C) scleral flap exposed and a cellulose sponge soaked in 0.4 mg% MMC kept over it for 2 minutes (followed by copious irrigation), (D) scleral flap lifted off the scleral bed till aqueous starts flowing. Complete dissection of the flap upto limbus is not required, (E) reposition of the scleral flap as aqueous oozes. Balanced salt solution injected through the paracentesis to ensure patency. One releasable suture applied at the apex of the flap, (F) conjunctiva sutured with 10-0 Vicryl
of previous sutures. The edges of the flap are delineated with a slit knife and the flap lifted off the scleral bed with blunt dissection aided by Vanna’s scissors, till aqueous started flowing. The flap is then reposited and fluid injected into anterior chamber through the paracentesis port to ensure the patency of filtration site. A 10-0 nylon releasable suture is
JAYPEE
JOCGP Bleb Revision
applied at the apex of the sclera flap. At the end of the procedure, the conjunctiva is sutured with 10-0 Vicryl suture and checked for any buttonholing or wound leak. Preventing a bleb from failing starts at the time of surgery and involves both intensive postoperative care and/or surgical intervention. Postoperatively, surgeons must promptly recognize a leaking or failing bleb to maximize the likelihood of its rescue. A failing or failed bleb requires careful evaluation and management according to the predominant cause of failure. So, let us get on to the business of saving failing blebs with the help of the aforementioned modalities.
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