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First Author: I.Novytskyy UKRAINE
Co Author(s): M. Novytskyy
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To development the intraoperative imagination of the aqueous outflow system in order to determine the level of the aqueous humor resistance.
This study was performed at the Lviv medical center Microsurgery of the eye, 8-th city hospital, Lviv, Ukraine.
20 patients with primary open-angle glaucoma were planned for the surgery of the trabecula removal through the anterior chamber angle (endotrabeculoectomy). In order to determine if the collector channels are patency, a reflux of blood into the Schlemms canal has been provoked intraoperatively. For this purpose, specially designed instruments in the form of a ring with a diameter of 13.5 mm pinched the episcleral veins for 2 minutes after paracentesis and partial emission of aqueous humor from the anterior chamber. Three degrees of the Shlemms canal blood filling, namely: 1 - no filling, 2 incomplete filling (irregular blood strip in the Shlemms canal), 3 - complete filling (continuous red band), were estimated using the gonioscope. The first degree was evaluated as obstruction of collectors and showed impossibility of the endotrabeculoectomy. At the second degree the trabecula has been removed in the areas where the Shlemms canal was filled with blood. At the third degree the endotrabeculectomy has been performed in one randomly selected quadrant. After the viscoelastic aspiration, the fluorescein was injected into the anterior chamber, intraocular pressure was increased with irrigation system and the passage of the dye into episcleral veins has been observed.
The first degree of the Shlemms canal blood filling was observed in 1 of the 20 patients (5%). In this case deep sclerectomy was performed. In 4 patients (20%) the Shlemms chanal filling was incomplete. Endotrabeculoectomy was performed in the areas where the Shlemms canal was filled with blood. In 15 patients (75%) a third degree of the Shlemms canal blood filling was observed. These patients underwent endotrabeculoectomy in the one randomly selected quadrant. In all patients after endotrabeculoectomy and the viscoelastic aspiration in the area of the removed trabecula anterior chamber blood reflux was observed, which was evaluated as a positive prognostic surgery sign. After filling the anterior chamber with fluorescein in all cases observed passage of the dye into episcleral veins in remote trabecula areas, which confirmed patency of collectors and the correctness of the surgical tactic. As a result of the endotrabeculoectomy, intraocular pressure has been decreased in all 19 patients. Thus before surgery mean IOP at the maximum medications was 19,5ḟ2,1 mmHg, while six months after the surgery - 15,0ḟ1,6 mmHg (p <0.001).
The intraoperative visualization of the aqueous humor outflow system can determine the level of the outflow resistance, help to choose a surgical tactic, estimate of the drainage system patency and predict the success of the surgery.