Purpose
To evaluate long-term tonometric outcomes of same-site trabeculectomy revision with mitomycin C (MMC) after failure of an initial trabeculectomy, and to identify risk factors for failure in patients with open-angle glaucoma.
Design
Retrospective cohort study.
Methods
One-hundred and seventeen patients (130 eyes) with primary open-angle, pseudoexfoliation, or pigmentary glaucoma, who failed a first trabeculectomy and who were ≥40 years of age at the time of same-site trabeculectomy revision, were included. Three levels of success criteria were defined: (A) intraocular pressure (IOP) ≤18 mm Hg and IOP reduction of 20%; (B) IOP ≤15 mm Hg and IOP reduction of 25%; and (C) IOP ≤12 mm Hg and IOP reduction of 30%. The primary outcome was the qualified Kaplan-Meier success rate (with or without medications) for each criterion. Cox multivariate regression analysis was used to identify risk factors for failure.
Results
The success rates (± standard error) at the first, third, and fifth years of follow-up for criterion A were 69.7% (± 4.1%), 58.2% (± 4.6%), and 51.1% (± 5.0%); for criterion B these were 60.9% (± 4.4%), 47.8% (± 4.7%), and 44.0 (± 4.8%); and for criterion C, 44.6% (± 4.5%), 29.7% (± 4.4%), and 25.8% (± 4.3%). Mean follow-up was 5.2 (± 3.6) years. A time interval between the first and the same-site trabeculectomy revision of <3 years, worse baseline visual acuity, and dyslipidemia were significant risk factors for failure.
Conclusions
Given the long-term tonometric success rates along with significant medication reduction, same-site trabeculectomy revision with MMC should be considered as a viable option to achieve reasonable IOP targets after a first failed trabeculectomy in open-angle glaucoma patients.
Trabeculectomy, first introduced in 1967, has become the most commonly used form of incisional surgery for the treatment of glaucoma. Adjunctive metabolites, most commonly mitomycin C (MMC), increase the success rate of surgery, as measured by tonometric outcomes. However, trabeculectomy generally fails with time, and though a second trabeculectomy is believed to have a lower success rate than the first, it is frequently performed after a first trabeculectomy fails. Unlike a second trabeculectomy, same-site trabeculectomy revision does not sacrifice a new region of fresh conjunctiva. We studied the long-term tonometric outcomes of same-site trabeculectomy revision with MMC in open-angle glaucoma patients after failure of an initial trabeculectomy, and identified risk factors for surgical failure.
Methods
Patients
This retrospective cohort study included patients who underwent a same-site trabeculectomy revision with adjunctive MMC for open-angle glaucoma between February 1, 1997 and May 31, 2015 at the Glaucoma Division of the Jules Stein Eye Institute, University of California Los Angeles. One-hundred and seventeen patients (130 eyes) with primary open-angle (POAG), pseudoexfoliation glaucoma (PXG), or pigmentary glaucoma (PG) who were 40 years of age or older at the time of the second same-site trabeculectomy were considered for inclusion. Indications for a second same-site trabeculectomy revision were (1) intraocular pressure (IOP) consistently above the target on maximum tolerated medication or (2) glaucomatous progression with evidence of visual field or optic nerve worsening, as judged by the treating physician, regardless of the measured IOP. Patients who had prior uncomplicated clear corneal cataract surgery with phacoemulsification were included. Eyes with previous tube shunts, with Ex-press Minishunts (Alcon Inc, Fort Worth, Texas, USA), or having had any other surgery involving the conjunctiva, except for trabeculectomy, were excluded. Other exclusion criteria were coexisting retinal or neurological diseases that may have affected the visual acuity or visual field, a diagnosis of other types of glaucoma, and a follow-up period of less than 3 months. The study protocol was approved by the Institutional Review Board at the University of California Los Angeles, and all study procedures adhered to the recommendations of the Declaration of Helsinki and conformed with HIPAA policy.
For each patient, the following data were collected from the medical record: age at the time of the first trabeculectomy, time interval between the first and second trabeculectomies, sex, race, eye laterality, family history of glaucoma, smoking status, previous laser and surgical history, concurrent ocular and systemic diseases, mean deviation and pattern standard deviation of the baseline preoperative visual fields, preoperative best-corrected visual acuity (BCVA), refractive error, central corneal thickness (CCT), lens status, number of medications, and mean preoperative IOP (mean of last 3 preoperative IOP readings on different days and within 6 month before surgery). Intraoperative data that were collected include concentration and duration of MMC application and intraoperative complications. Postoperative data that were collected were all measurements of IOP, number of medications, visual acuity, duration of follow-up, performance and timing of postoperative laser suture lysis, postoperative complications, and any ocular surgery performed after the same-site revision.
Surgical Technique
All surgeries were performed by the attending surgeons of the Jules Stein Eye Institute. Retrobulbar or peribulbar anesthesia with a 50/50 mixture of 2% lidocaine and 0.75% Marcaine (bupivacaine) was used. Trabeculectomy revisions were performed with either a fornix-based or a limbus-based conjunctival flap; all conjunctival incisions were centered at the 12 o’clock position. A 6-0 silk traction suture was placed in the peripheral cornea in the fornix-based approach, and a 4-0 silk bridle suture was placed under the tendon of the superior rectus muscle in the limbus-based approach. For fornix-based surgery, a conjunctival flap was prepared superiorly with an incision at the limbus and the conjunctiva and Tenon capsule were dissected to the fornix. For limbus-based surgery, a conjunctival flap was prepared superiorly with an incision 10–12 mm posterior to the limbus and the conjunctiva and Tenon capsule were dissected to the limbus. A thin cellulose sponge (approximately 6 × 12 mm) soaked with MMC (0.2–0.4 mg/mL) was placed over the site of the previous scleral flap for 1–3 minutes. The concentration and duration of MMC application were based on the preoperative evaluation of each patient’s presumed risk factors for failure (age, race, conjunctival hyperemia, inflammation, scarring), but most patients had a 1-minute exposure. The prior scleral flap was identified and re-dissected. The flap was lifted; the prior trabeculectomy block (approximately 2.5 × 1 mm) was exposed or re-dissected when necessary, and a basal iridectomy was identified or performed. The scleral flap was fixed with 2 sutures of 10-0 nylon at its corners. For the fornix-based approach, the conjunctiva and Tenon capsule were tightly reapposed to the limbus at the 2 corners of the incision with 2 10-0 Vicryl (polyglactin) sutures. For limbus-based surgery, at the end of surgery, the conjunctiva and Tenon capsule were closed in 1 layer with 9-0 Vicryl suture. Postoperatively, a topical corticosteroid was administered 4 times daily for 1–2 weeks and then tapered over 4–8 weeks. Cataract extraction, when indicated during the follow-up period, was performed at least 6 months after the same-site trabeculectomy revision and consisted of phacoemulsification with a temporal clear-cornea approach, with care taken to avoid trauma to the bleb. A posterior-chamber intraocular lens was inserted in the capsular bag in all patients.
Statistical Methods
The primary outcome measure was the qualified success rate (success with or without medications) based on different targets of IOP and reduction of medications; 3 different criteria were used and are defined in Table 1 . Secondary outcomes were mean IOP and number of medications of all eyes. We have included both survived and failed for the analysis at 1, 3, and 5 years after surgery, intraoperative and postoperative complications, and need for further glaucoma surgery.
| Criteria | Definition |
|---|---|
| Criterion A | Final IOP ≤18 mm Hg and 1 of the following: ≥20% reduction of IOP or a reduction of 2 medications with final IOP ≤ baseline IOP if baseline IOP ≤18 mm Hg. |
| Criterion B | Final IOP ≤15 mm Hg and 1 of the following: ≥25% reduction of IOP or a reduction of 2 medications with final IOP ≤ baseline IOP if baseline IOP ≤15 mm Hg. |
| Criterion C | Final IOP ≤12 mm Hg and 1 of the following: ≥30% reduction of IOP or a reduction of 2 medications with final IOP ≤ baseline IOP if baseline IOP ≤12 mm Hg. |
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
