微型组织瓣静脉回流的实验研究

An experimental study on the venous drainage of mini tissue flaps

目的建立 SD 大鼠微型组织瓣实验模型,探讨静脉逆向回流的机制。方法对30只SD 大鼠后肢进行解剖,建立隐动脉微型组织瓣实验模型(组织瓣面积为1.0 cm×1.0 cm)。将30只SD 大鼠的两侧后肢随机配对分为2组,进行同体对照,每组30块组织瓣。组1保留进入组织瓣的隐动脉和伴行静脉,切断所有进入组织瓣的其他血管;组2保留进入组织瓣的隐动脉,切断结扎隐动脉之伴行静脉和所有进入组织瓣之浅表静脉。术后观察组织瓣成活情况、质地及弹性;同时通过血管造影观察静脉回流重建的情况。结果组织瓣肿胀:术后第1天,组1所有组织瓣皮肤颜色正常,仅3块出现轻微肿胀,皮瓣质地弹性好;第2天肿胀消退。术后第1天,组2所有组织瓣皮肤颜色轻微淤紫,肿胀明显,皮瓣质地较紧张;第2天,所有组织瓣皮肤淤紫消退、肿胀明显转变为轻微肿胀,紧张度减轻;两组差异有统计学意义(P<0.01)。术后第3、7、9、14天,两组差异无统计学意义(P>0.05)。组织瓣存活:组1除1块皮缘有0.1 cm 皮肤干性坏死,其余组织瓣全部存活。组2有2块皮缘有0.1cm 皮肤干性坏死,3块组织瓣湿性坏死;其余组织瓣皮肤颜色正常,无肿胀,皮瓣质地、弹性略差。结论微型组织瓣移植有别于大面积组织瓣移植,其静脉回流重建主要在术后前三天依靠组织瓣与受区创面和创缘建立侧支循环。在确保动脉吻合通畅的情况下,由于各种原因导致静脉吻合失败,仍有较高的成活率。但要具有良好组织瓣质地,动、静脉吻合通畅仍是其必备条件。

Objective To set up an animal model of mini tissue flaps and explore the mechanism of retrograde vein drainage. Methods A mini tissue flap based on the saphenous artery （flap size： 1.0 cm × 1. 0 cm） was created on both hind limbs of 30 Sprague Dawley rats. The left and right hind limbs of each rat were randomly assigned into group 1 and 2. In group 1, the flaps were elevated and the saphenous artery and its accompanying veins were kept in situ. In group 2, the flaps were elevated and only the saphenous artery were kept in situ, while its accompanying veins and other superficial veins were ligated. Survival of the flaps, their appearance and consistency were observed. Reconfiguration of venous drainage of the flaps was evaluated by angiography. Results Flaps of group 1 had normal skin color at postoperative day 1. Only 3 flaps in this group showed mild swelling which subsided at postoperative day 2. All flaps had normal consistency. All the flaps of group 2 showed mild cyanosis and obvious swelling at postoperative day 1. There was tension of the flaps. Swelling of the flaps decreased and color of the flaps turned normal at postoperative day 2. Tension of the flaps also reduced. For swelling of the flaps, the difference between the two groups were statistically significant in the first and second days postoperatively （ P 〈 0.01）, but insignificant in the 3,7,9 and the 14 days postoperatively. For flap survival, in group 1 all flaps survived with normal skin color, good appearance and elasticity except one flap presented about 0.1 cm marginal skin necrosis. In group 2, there were 2 flaps with about 0.1 cm marginal skin necrosis and 3 flaps with complete necrosis. The survived flaps had normal skin color and no swelling, but their appearance and elasticity were slightly worse than that of the flaps in group 1. Conclusion The survival mechanism of mini tissue flaps is different from that of conventional flaps. Restoration of venous drainage relies on collateral anastomosis between the flap and its tissue bed and surrounding margins in the first 3 postoperative days. When arterial flow is patent, mini tissue flaps still have a high survival rate even if the venous flow is obstructed due to a failed vein anastomosis. However a good venous anastomosis is required to ensure good flap appearance and consistency.