Abe Ichiro, Tsujino Akihito, Hara Yuki, Ichimura Harumitsu, Ochiai Naoyuki
Department of orthopedic surgery, University of Tsukuba, 1-1-1 Tennodai, Tsukuba-shi, Ibaraki 305-8575, Japan.
Acta Neuropathol. 2002 Nov;104(5):505-12. doi: 10.1007/s00401-002-0584-y. Epub 2002 Jul 4.
Nerve elongation resulting from leg-lengthening surgery can be injurious. We investigated peripheral nerve injury and recovery after gradual elongation of the rat sciatic nerve by progressive stretching. Indirect nerve elongation was produced by leg lengthening by 15 mm, at a rate of 3 mm/day (group I) or 5 mm/day (group II). The elongated length was then maintained. At 0 weeks, representing the 7th day after starting leg lengthening, and at weeks 2, 4, and 6, transverse semithin sections of sciatic nerve were examined. At the same time a teased fiber study was performed. As a result of nerve elongation axon diameter was decreased, although it later recovered. Axon diameter recovered more slowly in group II than I. Myelin thickness did not change compared with controls. In the teased fiber study, internodal length was increased by about 10% after nerve elongation in each group. Almost all nerve fibers showed demyelination at 0 weeks; myelination recovered with time, more slowly in group II than I. More obvious demyelination, axonal degeneration, and remyelination were observed in group II. We conclude that mild demyelination was repaired by elongation of internodes, while more severe demyelination was repaired by intercalation of segments.
腿部延长手术导致的神经延长可能具有损伤性。我们通过渐进性拉伸对大鼠坐骨神经进行逐渐延长，从而研究周围神经损伤及恢复情况。通过将腿部延长15毫米产生间接神经延长，延长速率为每天3毫米（第一组）或每天5毫米（第二组）。然后维持延长后的长度。在代表开始腿部延长后第7天的第0周以及第2、4和6周，对坐骨神经的横向半薄切片进行检查。同时进行神经纤维分离研究。神经延长的结果是轴突直径减小，不过随后有所恢复。第二组轴突直径的恢复比第一组更慢。与对照组相比，髓鞘厚度没有变化。在神经纤维分离研究中，每组神经延长后节间长度增加约10%。在第0周时几乎所有神经纤维都出现脱髓鞘；髓鞘形成随时间恢复，第二组比第一组恢复得更慢。在第二组中观察到更明显的脱髓鞘、轴突变性和髓鞘再生。我们得出结论，轻度脱髓鞘通过节间延长得以修复，而更严重的脱髓鞘则通过节段插入得以修复。
