Seo Mi Hyun, Kim Soung Min, Huan Fan, Myoung Hoon, Lee Jong Ho, Lee Suk Keun
*Department of Oral and Maxillofacial Surgery, Oral Cancer Center, Dental Research Institute, School of Dentistry, Seoul National University, Seoul †Department of Oral Pathology, College of Dentistry, Gangneung-Wonju National University, Gangneung, South Korea.
J Craniofac Surg. 2015 Oct;26(7):2047-51. doi: 10.1097/SCS.0000000000002111.
Microvascular flap reconstruction is known as successful technique, although vascular thrombosis can cause free flap failure. To analyze the histologic characteristics and causes of free flap failure, this clinical study examined failed free flaps, including the microanastomosed sites. This study included a total of 5 failed flaps, including 3 radial forearm free flaps, 1 latissimus dorsi free flap, and 1 fibular free flap, all performed with microvascular reconstruction surgery from 2009 to 2011 at Seoul National University Dental Hospital. At the resection surgeries of the failed nonviable flaps, histologic specimens including the microanastomosed vessels were acquired. For light microscope observation, the slides were stained with hematoxylin and eosin (HE), and also with Masson trichrome. Selected portions of graft tissue were also observed under transmission electron microscope (TEM). It was found that the cause of flap failure was the occlusion of vessels because of thrombi formation. During the microanastomosis, damage to the vessel endothelium occurred, followed by intimal hyperplasia and medial necrosis at the anastomosed site. In the TEM findings, some smooth muscle cells beneath endothelium were atrophied and degenerated. The formation of thrombi and the degeneration of the smooth muscle cells were coincident with vascular dysfunction of graft vessel. The damaged endothelium and the exposed connective tissue elements might initiate the extrinsic pathway of thrombosis at the microanastomotic site. Therefore, it is suggested that accurate surgical planning, adequate postoperative monitoring, and skillful technique for minimizing vascular injury are required for successful microvascular transfer.
微血管皮瓣重建术是一种成功的技术，尽管血管血栓形成可能导致游离皮瓣失败。为了分析游离皮瓣失败的组织学特征及原因，本临床研究对失败的游离皮瓣进行了检查，包括微血管吻合部位。本研究共纳入5例失败皮瓣，其中3例为桡侧前臂游离皮瓣，1例为背阔肌游离皮瓣，1例为腓骨游离皮瓣，均于2009年至2011年在首尔国立大学牙科学院接受微血管重建手术。在对失败的无活力皮瓣进行切除手术时，获取了包括微血管吻合血管在内的组织学标本。为进行光学显微镜观察，玻片用苏木精和伊红（HE）染色，也用马松三色染色。移植组织的选定部分也在透射电子显微镜（TEM）下观察。结果发现皮瓣失败的原因是血栓形成导致血管闭塞。在微血管吻合过程中，血管内皮发生损伤，随后吻合部位出现内膜增生和中层坏死。在TEM检查结果中，内皮下方的一些平滑肌细胞萎缩和变性。血栓形成和平滑肌细胞变性与移植血管的血管功能障碍同时发生。受损的内皮和暴露的结缔组织成分可能在微血管吻合部位启动血栓形成的外源性途径。因此，建议成功的微血管转移需要精确的手术规划、充分的术后监测以及熟练的技术以尽量减少血管损伤。
