目的 通过皮窗对大鼠背部跨区皮瓣Choke静脉的变化情况进行观察。方法 首先利用氧化铅-明胶一次性整体血管灌注技术，对30只SD大鼠背部血管的分布情况进行研究；然后在10只SD大鼠背部一侧切取大小为10.0cm×3.5cm的跨区皮瓣，放置皮窗，用体视显微镜连续观察8d并摄片记录Choke动静脉的变化情况。另2只大鼠同法安置皮窗后，尾静脉注射2%伊文思蓝各1ml，视频记录Choke区动静脉的循环过程。结果 跨区皮瓣切取后，Choke区的动脉与静脉管径均扩张，连接小静脉于术后（60±12）h开始出现管径扩张，一直延续到（4.5±0.5）d。通过尾静脉注射伊文思蓝，可以完整地观察到Choke动静脉的循环过程，其动脉血流速度2.53mm/s。 结论 在皮瓣切取后的早期，静脉血主要以“迷宫”式回流为主，而术后晚期则通过“迷宫式”及“瓣膜失效”两种方式进行回流，以“瓣膜失效”为主。伊文思蓝可作为一种血流示踪剂，与皮窗直视观测相结合，适用于皮瓣内的微循环血流动力学研究。

Objective To investigate the changs of Choke veins for cross-area flap at the dorsum of the rat. Methods Firstly, the vessels distribution of 30 SD rats was studied by lead oxide-gelatin one-time whole vascular perfusion technique. Secondly, a cross-area flap at the size of 10.0cm×3.5cm was cut out at either side of dorsum in 10 SD rats and placed in the skin window. The changes of Choke vessels were observed and photographed for 8 days under the stereomicroscope. The skin windows were placed in another 2 SD rats before 2% Evans blue was injected about 1 ml in each rat by tail vein and the microcirculation of choke vessels was recorded by video. Results After the cross-area flap was cut out, the vascular diameter dilated in both choke artery and veins. However, the most obvious dilation was found in the connection venules. The dilation of connection venules began at the (60±12)th hour after operation and continued till (4.5±0.5) days. The whole circulation process was observed in the Choke vessels by Evans blue injection in tail vein and the blood velocity at the choke artery was approximately 2.53mm/s. Conclusion In the earlier stage following the flap cutting out, the backflow of venous blood gives priority to the labyrinth type, while the backflow of venous blood is valve failure in preference to the labyrinth type at the later stage. Evans blue as a blood tracer is suitable for the blood blow dynamics research in the microcirculation of skin flap when combining with the direct observation of skin window.