Reconstruction of a 10-mm-long median nerve gap in an ischemic environment using autologous conduits with different patterns of blood supply: A comparative study in the rat

The aim of this study was to evaluate in the Wistar rat the efficacy of various autologous nerve conduits with various forms of blood supply in reconstructing a 10-mm-long gap in the median nerve (MN) under conditions of local ischemia. A 10-mm-long median nerve defect was created in the right arm. A loose silicone tube was placed around the nerve gap zone, in order to simulate a local ischemic environment. Rats were divided in the following experimental groups (each with 20 rats): the nerve Graft (NG) group, in which the excised MN segment was reattached; the conventional nerve flap (CNF) and the arterialized neurovenous flap (ANVF) groups in which the gap was bridged with homonymous median nerve flaps; the prefabricated nerve flap (PNF) group in which the gap was reconstructed with a fabricated flap created by leaving an arteriovenous fistula in contact with the sciatic nerve for 5 weeks; and the two control groups, Sham and Excision groups. In the latter group, the proximal stump of the MN nerve was ligated and no repair was performed. The rats were followed for 100 days. During this time, they did physiotherapy. Functional, electroneuromyographic and histological studies were performed. The CNF and ANVF groups presented better results than the NG group in the following assessments: grasping test, nociception, motor stimulation threshold, muscle weight, and histomorphometric evaluation. Radial deviation of the operated forepaw was more common in rats that presented worse results in the other outcome variables. Overall, CNFs and ANVFs produced a faster and more complete recovery than NGs in the reconstruction of a 10-mm-long median nerve gap in an ischemic environment in the Wistar rat. Although, results obtained with CNFs were in most cases were better than ANVFs, these differences were not statistically significant for most of the outcome variables.本研究旨在评估不同血供形式的自体神经导管，在局部缺血条件下重建Wistar大鼠正中神经（median nerve, MN）10mm长度缺损的效果。研究者在大鼠右臂构建10mm长的正中神经缺损模型，并于神经缺损区域周围放置疏松硅胶管以模拟局部缺血环境。将大鼠分为以下实验组（每组20只）：神经移植（nerve graft, NG）组，即将切除的正中神经节段原位再吻合；常规神经皮瓣（conventional nerve flap, CNF）组与动脉化神经静脉皮瓣（arterialized neurovenous flap, ANVF）组，均采用同名正中神经皮瓣桥接神经缺损；预制神经皮瓣（prefabricated nerve flap, PNF）组，采用于坐骨神经旁留置动静脉瘘5周构建的预制皮瓣修复缺损；另设假手术（Sham）组与切除组两个对照组：切除组仅结扎正中神经近断端，未行任何修复处理。所有大鼠术后随访100天，并在此期间接受物理治疗。术后开展功能学、神经肌电生理学及组织学检测。在抓握功能测试、痛觉感知、运动刺激阈值、肌肉重量及组织形态计量学评估中，CNF组与ANVF组的修复效果均优于NG组。手术侧前肢桡偏现象在其他结局指标表现较差的大鼠中更为常见。总体而言，在Wistar大鼠局部缺血环境下重建10mm长正中神经缺损的实验中，CNF与ANVF可实现较NG组更快且更完全的功能恢复。尽管多数情况下CNF组的修复效果优于ANVF组，但二者在多数结局指标上的差异未达到统计学显著性。