Stratmann U, Schaarschmidt K, Lehmann R R, Heinze A, Willital G H, Unsöld E
Institute of Anatomy, University of Münster, Germany.
Scanning Microsc. 1995 Sep;9(3):805-14; discussion 815-6.
This study investigates tissue responses after laser irradiation of the rabbit ureter, which serves as an experimental model for rectourogenital fistulae of children. Twenty-five rabbit ureters were irradiated intraluminally by a Nd:YAG laser 1320 nm (2 Watt, 20 seconds and 3 Watt, 8 seconds) via an applicator with radialsymmetrical light distribution. Immediately, 2 weeks, 4 weeks, 8 weeks, and 16 weeks after irradiation, the ureters were X-rayed with contrast solution and prepared for light and transmission electron microscopy. For the parameters employed, no apparent morphological differences could be observed. Immediately, the central laser zone showed a transmural thermonecrosis prevailed by cellular destruction, condensed ground substance and occlusion of most vascular lumina. Peripheral laser zones displayed urothelial vacuolations. Between 2 and 16 weeks, urothelial regeneration and ingrowth of granulation tissue caused a luminal stenosis or occlusion followed by transformation into scar tissue. In some peripheral laser zones, a hydroureter with marked luminal dilatation developed. We conclude that the ureter is occluded if the expanding force of the growing scar tissue exceeds the hydrostatic pressure of the obstructed urine. A laser occlusion of rectourogenital fistulae will be easier to achieve since fistula occlusion does not entail an obstruction of the urine flow.
本研究调查了兔输尿管经激光照射后的组织反应，兔输尿管作为儿童直肠泌尿瘘的实验模型。通过具有径向对称光分布的施照器，用波长1320nm的Nd:YAG激光（2瓦，20秒和3瓦，8秒）对25条兔输尿管进行腔内照射。照射后即刻、2周、4周、8周和16周，用造影剂对输尿管进行X线检查，并制备用于光镜和透射电镜检查的标本。在所采用的参数下，未观察到明显的形态学差异。照射后即刻，中央激光区呈现透壁性热坏死，主要表现为细胞破坏、基质浓缩和大多数血管腔闭塞。周边激光区可见尿路上皮空泡形成。在2至16周之间，尿路上皮再生和肉芽组织长入导致管腔狭窄或闭塞，随后转变为瘢痕组织。在一些周边激光区，出现了伴有明显管腔扩张的肾盂积水。我们得出结论，如果生长的瘢痕组织的扩张力超过梗阻尿液的静水压力，输尿管就会被阻塞。由于瘘管闭塞不会导致尿液流动受阻，因此激光闭塞直肠泌尿瘘将更容易实现。
