Nerve regeneration patterns after acute ischemic injury.

We performed morphologic studies on regeneration of the cat's hind limb nerves, following simultaneous ligation of the aorta and right femoral artery. There were 2 regeneration patterns depending on the extent of ischemic necrosis. When nerve infarcts were limited only to intrafascicular regions, there was no basic change of nerve microarchitecture during regeneration. Extension of the necrosis to the perineurium resulted in replacement of the original fascicle by a collection of small fascicles, many of which were surrounded by their own perineurium. These minifascicles formed within the boundaries of the old perineurium.