Klink T, Lieb W, Grehn F
Universitäts-Augenklinik Würzburg, Germany.
Graefes Arch Clin Exp Ophthalmol. 2000 Sep;238(9):792-6. doi: 10.1007/s004170000169.
Deep sclerectomy and viscocanalostomy are becoming more and more popular as non-penetrating filtering procedures. The purpose of the present study was to simplify the technique of this procedure and to reduce the rate of unintended perforations during the preparation of the deep lamella.
20 enucleated porcine eyes were used. A superficial lamellar scleral flap with an area of 5x5 mm as for trabeculectomy was surgically prepared. Using a pulsed erbium:YAG laser the deep lamella (220 +/- 40 microm) with an area of 4x3 mm was removed. Ablation was performed with an energy of 40-100 mJ, a frequency of 1-10 Hz and a spot size of 500 microm and 1 mm (divergent beam). During the procedure the intraocular pressure was kept constant by continuous infusion. Finally the eyes were analyzed histologically.
After initial trials it was possible to ablate the remaining deep corneoscleral lamella with the erbium:YAG laser without perforating into the anterior chamber. Starting with an energy of 70-85 mJ and a reduction to 40-60 mJ when reaching deeper layers, a spot size of 500 microm and a 10 Hz repetition rate gave the highest safety and efficiency in preparation. After a learning curve it was possible to preserve Descemet's membrane and intact trabecular meshwork in 10 consecutive operations as demonstrated by histology.
Erbium:YAG laser-assisted deep sclerectomy offers an alternative to microsurgical preparation of the deep scleral lamella. The thermal damage is minimal (10-40 microm) and scarring may therefore not be stimulated.
作为非穿透性滤过手术，深层巩膜切除术和粘小管切开术越来越受欢迎。本研究的目的是简化该手术技术，并降低深层板层制备过程中意外穿孔的发生率。
使用20只摘除的猪眼。手术制作一个面积为5×5mm的浅层巩膜瓣，如同小梁切除术。使用脉冲铒：YAG激光切除面积为4×3mm、厚度为220±40微米的深层板层。以40 - 100mJ的能量、1 - 10Hz的频率和500微米及1mm的光斑尺寸（发散光束）进行消融。手术过程中通过持续灌注使眼压保持恒定。最后对眼睛进行组织学分析。
经过初步试验，可以用铒：YAG激光消融剩余的深层角膜巩膜板层而不穿入前房。从70 - 85mJ的能量开始，到达较深层时降至40 - 60mJ，500微米的光斑尺寸和10Hz的重复频率在制备过程中提供了最高的安全性和效率。经过学习曲线后，组织学显示在连续10次手术中可以保留Descemet膜和完整的小梁网。
铒：YAG激光辅助深层巩膜切除术为深层巩膜板层的显微手术制备提供了一种替代方法。热损伤最小（10 - 40微米），因此可能不会刺激瘢痕形成。
