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Abstract #5627 Published in IGR 2-1
Photoablative laser-grid trabeculectomy in glaucoma filtering surgery: histology and outflow facility measurements in porcine cadaver eyes
Jacobi PC; Dietlein TS; Coiling T; Krieglstein GKOphthalmic Surgery and Lasers 2000; 31:49-54
BACKGROUND AND OBJECTIVES: Mid-infrared laser technology opens new perspectives in experimental glaucoma surgery. The aim of the study was to determine the efficacy of grid-laser trabeculectomy to reduce aqueous outflow resistance sufficiently in perfused porcine cadaver eyes. MATERIALS AND METHODS: Twenty-five freshly enucleated porcine cadaver eyes were randomly assigned to either laser-grid trabeculectomy (LGT), conventional trabeculectomy (CT), or control. In all surgical cases a scleral flap was prepared in a standardized manner. In order to penetrate into the anterior chamber a 1x2 mm sclerectomy was performed in CT, and ten transscleral ablation craters were created in L GT. An erbium:YAG laser (2.96 μm) was used for transscleral photoablation. Radiation was delivered in a single 6 mJ-pulse of 200 μsec duration by means of an articulated zirconium fluoride optical fiber and a 200 μm quartz fiber-tip. Outflow facility was measured at a constant perfusion pressure. RESULTS: Laser-grid trabeculectomy (LGT) yielded reproducible ablation areas varying between 210-300 μm in diameter, with 90% being full-thickness penetrations. Collateral thermal damage was less than 30 μm. Outflow facility measurements revealed a statistically significant increase (mean ± SD) from 0.255±0.096 μl/min/mmHg in control eyes (n=9) to 0.772±0.157 μl/min/mmHg in the LGT group (n=9), and 2.957±0.602 μl/min/mm in the CT group (n=7). Flattening of the anterior chamber, folding of Descemet's membrane, and iris prolapse were only observed in the CT eyes, not in the GLT group. CONCLUSIONS: Application of the laser-grid trabeculectomy produces patent transscleral perforation with minimal collateral tissue damage and effects a significant reduction (67%) in outflow resistance without any postoperative hypotony-related complications.
Dr. P.C. Jacobi, University Eye Hospital of Cologne, Joseph-Stelzmannstrasse 9, 50931 Cologne, Germany
Classification:
5 Experimental glaucoma; animal models
12.8.4 Using laser (Part of: 12 Surgical treatment > 12.8 Filtering surgery)
