THE MORPHOGENESIS OF THE AQUEOUS OUTFLOW PATHWAYS AND THE ASSESSMENT OF HYPOTENSIVE EFFECT OF THE EX-PRESS MINI-SHUNT IMPLANTATION

• Main Authors: N. V. Volkova, T. N. Iureva
• Format: Article
• Language: Russian
• Published: Publishing house "Ophthalmology" 2015-12-01
• Series: Офтальмохирургия
• Subjects: ex-press; glaucoma surgery; hyper-scarring of aqueous outflow pathways; ultrabiomicroscopic monitoring
• Online Access: https://www.ophthalmosurgery.ru/jour/article/view/134

Purpose. To investigate the morphogenesis of the aqueous humor (AH) outflow pathways and to assess the hypotensive effect of the modified implantation of Ex-PRESS mini-shunt.Material and methods. There were made 47 implantations of mini-shunts: in 10 cases – by the original technology, in 37 cases – by the modified one. The postoperative follow-up was 12-24 months. Pentacam examination allows excluding the contact of mini-shunt with the structures of anterior chamber angle. The assessment of the morphogenesis of the aqueous outflow pathways, the cause of IOP decompensation and the duration of hypotensive effect were defined during the ultrabiomicroscopic monitoring (UBM).Results. For the purpose of the stable and independent location of Ex-PRESS drainage it is advisable: for the discission of sclera to use the 30G needle directed at an angle of 30-50 against the iris surface; for the increase of the volume of intrascleral cavity – to cut out the scleral groove. The proposed nuances of the modified implantation exclude a hyper-filtration, a drainage dislocation and a tendency to scarring in the early postoperative period. In case of the adequate formed aqueous outflow pathways (n=38) the IOP level (Pt) was 14±3mmHg at first 24 hours, up to 6 months it was 19±3mmHg, and it was stable during the entire follow-up. After Ex-PRESS shunting the height of intrascleral cavity was 0.15-0.199mm, the scan height was 2.2±0.43mm in the adequate formed aqueous outflow pathways. The UBM data revealed that the aqueous outflow pathways were adequately formed in 28 cases, in 10 cases (21.3%) the transpebral massage was additionally administered, in 7 (14.9%) cases – the aqueous outflow pathways were partially sclerous, the additional hypotensive therapy was prescribed, in 2 (4.2%) cases the aqueous outflow pathways were failed.Conclusion. The indications for the Ex-PRESS implantation are an initially wide profile (430-450 and more) of the open anterior chamber angle or a previously performed laser iridectomy in case of the narrow anterior chamber angle. The creation of «unclosing» inner fistula is an undoubted advantage of Ex-PRESS implantation. The research of the morphogenesis of the aqueous outflow pathways after Ex-PRESS implantation in uncomplicated cases has revealed a formation of the classic filtering bleb in spite of an insignificant height of intrascleral channel. The cause of a failure of the hypotensive effect of the modified implantation of Ex-PRESS mini-shunt is an inadequate inflammatory reaction in the zone of intrascleral channel or bleb.