만성신경압박의 병리조직학적 고찰 = Histopathological Studies of Chronic Nerve Compression

다국어 초록 (Multilingual Abstract)

Recently nerve entrapments or nerve root compressions are common clinical symdromes. However, a clear understanding of both pathophysiological and morphological changes is lacking and it may not be completely established in the experimental model for chronic nerve compression, compared with a surprising review of peripheral nerve exposed to various acute damage.
Adult Sprague-Dawley rats weighing 250 to 300 g were used as the experimental model to elucidate histopathological changes in chronic nerve compression, which were produced by banding the sciatic nerve(normally 1.2㎜ in diameter) with the length of 1㎝ silastic tubings with inner diameter, 0.6㎜ (Group Ⅰ), 0.9㎜ (Group Ⅱ) and 1.5㎜ (Group Ⅲ) in each. Specimens were obtained for light and electron microscopic studies postoperatively at 1 and 3 months following by nerve conduction study.
Grossly in group Ⅰ, the sciatic nerve was compressed to approximately 50% of its normal in cuff area and in thin strand on distal part at 1 month and more progressed at 3 months.
The sciatic nerve of group Ⅱ demonstrated 75% of control and distal part in 50% compression at 1 month, but the nerve seemed not to be affected by tubing.
Light microscopic findings revealed Wallerian degeneration and diminished large myelinated fiber particularly in the periphery of nerves with 34% of transverse neural percentage in group Ⅰ at postoperative 1 month. Above findings were progressed to epineurial scarring and fibrosis at 3 months. There were marked diminution and deformity in large myelinated fiber in group Ⅱ, but it was not more severe than the ones of group Ⅰ.
Electron microscopic findings in this group revealed the appearance of small regenerating unit clusters and thinly myelinated fibers. In group Ⅲ, histological findings were not much different from that of normal nerve.
Nerve conduction study revealed the decrease in conduction velocity to mean 10 M/sec in group Ⅰ at 1 month and no electrical conduction at 3 months. In group Ⅱ, diminution of conduction velocity in 73% of normal range at I1month was noted, and 82% at 3 months.
These findings explain correspondingly the histopathological changes in part of chronic nerve entrapment syndromes and appeal the need of further investigation in this experimental model.