Needle Revision with and without Mitomycin C for the Teatment of Failed Filtering Blebs after Trabeculectomy

ABSTRACT

PURPOSE: To evaluate the effects of needle revision (NR) with and without mitomycin C (MMC) for failed filtering blebs after trabeculectomy, and to identify risk factors for failure. METHODS: Thirty-one eyes whose intraocular pressure (IOP) did not decrease after cutting of scleral flap sutures were recruited. NR was performed with a 26-gauge needle under a slit-lamp. Immediately following NR, 15 eyes received subconjunctival injection of 0.002 mg (0.02 mg/ml) MMC at the adjacent conjunctiva. RESULTS: First NR was done at 1.3+/-1.2 months (range, 0.2~6.5 months) after trabeculectomy, and a mean of 1.6+/-1.6 NRs per patient were done. The follow-up period was 24.4+/-20.4 months (range, 6.0~87.4 months) after the last NR. Pre-NR mean IOP was 27.9+/-11.6 mm Hg and post-NR final IOP was 18.8+/-13.0 mm Hg (p=0.005). The success rate, defined as IOP 25 mm Hg showed a higher failure rate, though with no statistical significance (p=0.141 and p=0.173, respectively). CONCLUSIONS: NR followed by subconjunctival injection of MMC is an effective and safe method for the treatment of the failed filtering blebs after trabeculectomy. Trabeculectomy without adjunctive MMC and pre-NR IOP higher than 25 mmHg were risk factors for failure of NR.