Brooks S E, Dacey M P, Lee M B, Baerveldt G
Doheny Eye Institute, University of Southern California School of Medicine, Los Angeles.
Ophthalmic Surg. 1994 May;25(5):311-6.
Hypotony or hypertension in the early postoperative period following implantation of a nonvalved seton such as the Molteno tube is a common problem. We conducted a laboratory investigation evaluating two modifications of the silicone drainage tube. One involved a longitudinally-oriented, pressure-sensitive slit-valve combined with an absorbable occluding ligature interposed between the valve and the episcleral plate. Experiments examining the relationship between slit length, opening pressure, and flow rate were performed. The second modification involves focally constricting the lumen of the tube with an external ligature in order to reduce flow rates. Our results indicate that a slit-valve length of 2.0 mm appears to provide a reliable opening pressure of around 10 mm Hg, with relatively high flow when pressures exceed opening pressure. Focally constricting the lumen of the tube, however, was shown to be both unpredictable and unsatisfactory for reducing the flow of fluid to a range consistent with steady state aqueous production.
在植入无瓣膜引流装置（如莫尔滕诺管）后的术后早期出现低眼压或高眼压是一个常见问题。我们进行了一项实验室研究，评估硅胶引流管的两种改良方法。一种方法是采用纵向的、对压力敏感的裂隙阀，并在瓣膜和巩膜板之间插入一个可吸收的阻塞结扎线。进行了检查裂隙长度、开启压力和流速之间关系的实验。第二种改良方法是用外部结扎线局部收缩管腔以降低流速。我们的结果表明，2.0毫米的裂隙阀长度似乎能提供约10毫米汞柱的可靠开启压力，当压力超过开启压力时流速相对较高。然而，事实证明，局部收缩管腔对于将液体流速降低到与房水稳态生成相一致的范围既不可预测也不能令人满意。
