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C. Nguyen, R. Boldea, S. Roy, T. Shaarawy, A. Mermoud; Deep Sclerectomy with Two Different Designs of Collagen Implant in an Animal Model: Final Results . Invest. Ophthalmol. Vis. Sci. 2003;44(13):3311.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To study experimentally the effect of the shape of two different collagen implants used in deep sclerectomy. The ability to promote drainage vessels, the outflow mechanisms, the success rates, and the biodegradability, were studied prospectively in an animal model. Methods: Deep sclerectomy was performed in 20 eyes of 10 rabbits. Each rabbit randomly received a cylindrical 1x1x4 mm collagen implant in one eye, while the other eye received a 4x4x0.15 mm flat collagen implant. Intraocular pressure (IOP), ultrasound biomicroscopy (UBM) examination and simultaneous fluorescein and ICG anterior-segment angiographies were performed preoperatively, at 1 and 2 weeks, 1, 2, 3, 6 and 9 months for each eye. At the end of the follow up period outflow facility was measured and histological examinations of the filtration site were performed. Results: In the cylindrical implant group, IOP significantly dropped from a mean preoperative value of 14.8±2.2 mmHg to a mean postoperative values of 10.9±3.3, 12.5±2.2, 11.8±2.6, 11.2±2.3, 10.7±1.9, 14.0± 3.2, 12.6±2.4 mm Hg at 1, 2 weeks, and 1,2,3,6, and 9 months respectively. In the flat collagen implant group, IOP significantly dropped from a mean preoperative value of 14.1±1.8 mmHg to a mean postoperative values of 10.4±2.7, 12.7±1.9, 12.5±3.2, 11.2±1.6, 11.6±1.8, 11.5±2.3, 11.0±2.2 mm Hg at 1, 2 weeks, and at 1,2,3,6, and 9 months respectively. Gradual resorption of both collagen implants was assessed with UBM images; complete resorption was observed between 2 and 3 months postoperatively with no significant differences. Angiographies showed, with both implants, a progressive growth of drainage vessels around the filtration site during first six months, with no significant differences. The mean outflow facility 9 months postoperatively for the cylindrical implant was 0.53± 0.23 ml/min/mm Hg and was 0.56± 0.17 ml/min/mm Hg for the flat implant (p=0.6). Histological examination revealed in both groups excellent biocompatibility and a significantly higher density of drainage vessels in the sclera around surgery site, with no significant differences according to type of implants. Conclusions: We were able to compare two types of collagen implants used in deep sclerectomy. Both collagen implants showed efficient IOP lowering effect and outflow facility increase throughout the 9 months of follow up. Growth of drainage vessels in the sclera surrounding the operated site was observed in both groups. Both implants were well tolerated in respect to biocompatibility. The flat collagen implant showed a tendency of having better overall performances.
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