Nishino S, Goya N, Ishikawa N, Tomizawa Y, Toma H
Department of Urology, Tokyo Women's Medical University, Tokyo, Japan.
BJU Int. 2002 Nov;90(7):730-5. doi: 10.1046/j.1464-410x.2002.02995.x.
To evaluate the efficacy and safety of self-expanding metallic stents after insertion into the canine ureter.
Actively expanding metallic (Nitinol) stents (diameter 8-10 mm, length 4-6 cm) were placed in eight mongrel dogs (18-34 kg). Under general anaesthesia, a midline abdominal incision was made and a stent inserted directly into the ureter through a small incision; each animal was stented on one side. The dogs were assessed after 6 or 19 days or 2, 5 (two), 6 (two) and 7 months. Ureteric specimens were evaluated both macroscopically and microscopically.
Macroscopically there was no leakage of urine in any of the animals. On day 6 the inserted stent was patent despite blood clots in the mesh. The lumen was smooth and shiny in three dogs examined at 5, 6 and 7 months. One of the two dogs assessed at both 5 and 6 months had hydronephrosis associated with papillary hyper-epithelialization inside the stent, while the other animals had no dilatation of the renal pelvis. Microscopically there was loss of epithelium and bleeding of the ureteric wall at 6 days. Epithelial regeneration started after 19 days and was complete in the lumen at 2 months, with the stent incorporated into the wall of the ureter. Epithelialization was maintained up to 7 months, after which the problem of urothelial hyperplasia persisted, but an adequate lumen was maintained by epithelial regeneration. This epithelium was smooth and shiny, and composed of thin layers of cells.
Self-expanding metallic stents may be effective if hyperplastic epithelialization does not occur, as the stent was epithelialized within 2 months and the regenerated epithelium maintained for up to 7 months. Metallic stents may be useful for treating patients with renal failure caused by ureteric stenosis from malignant tumours.
评估自膨式金属支架植入犬输尿管后的疗效和安全性。
将主动扩张型金属（镍钛合金）支架（直径8 - 10毫米，长度4 - 6厘米）植入8只杂种犬（体重18 - 34千克）体内。在全身麻醉下，经腹部正中切口，通过小切口将支架直接插入输尿管；每只动物仅一侧输尿管植入支架。分别在术后6天或19天，以及2、5（两次）、6（两次）和7个月对犬进行评估。对输尿管标本进行宏观和微观评估。
宏观上，所有动物均无尿液渗漏。术后6天，尽管网眼中有血凝块，但植入的支架通畅。在5、6和7个月检查的3只犬中，输尿管腔光滑且有光泽。在5个月和6个月均接受评估的2只犬中，有1只出现肾积水，伴有支架内乳头上皮增生，而其他动物肾盂无扩张。微观上，术后6天输尿管壁上皮缺失且有出血。术后19天开始上皮再生，2个月时管腔内再生完成，支架融入输尿管壁。上皮化维持至7个月，之后尿路上皮增生问题持续存在，但通过上皮再生维持了足够的管腔。该上皮光滑有光泽，由薄层细胞组成。
如果不发生增生性上皮化，自膨式金属支架可能有效，因为支架在2个月内实现上皮化，且再生上皮维持长达7个月。金属支架可能有助于治疗由恶性肿瘤导致输尿管狭窄引起的肾衰竭患者。
