Injuries of nerves and their consequences - Reflex Sympathetic ...

80 INJURIES OF NERVES.
small animals, as the rabbit, from two to four lines of lost
nerve may thus be made up, and in man there are certainly
instances of at least three inches having been restored.
While many of the peripheral fibres are still undergoing
destructive changes, and before the nerve ends are
reunited, the process of repair begins in the lower end of
the cut nerve, so that, in young animals, degeneration and
regeneration are going on in separate fibrils side by side.
Among the wasted tubules appear others, in which the
medullary matter is replaced, and in this manner gradually
the atrophied nerve tubes undergo a process of reparation
until the nerve is
recomposed, the newer elements
being smaller for a time than the original fibres. The
change thus effected appears to go on alike at one and
the same time in the whole length of altered nerve.
Waller was of the opinion that the fibres thus formed
were throughout new formations, but this view has been
refuted by both Schiff and Vulpian, and there is now but
little doubt that they are merely restorations of the original
tissue.
Until the reuniting tissue contains a considerable number
of healthy filaments, and until the lower nerve end
has undergone a large amount of restoration, the functions
of the nerve remain in abeyance, and the question
as to the time needed for repair, and of the extent of this
process, are therefore of the utmost importance in connection
with the prognosis and treatment of nerve injuries.
—
Autof/enetic restoration of nerves. Yulpian and Phillipeaux
have shown that even when the divided nerve ends
do not reunite, the peripheral extremity undergoes after a
considerable time a more or less complete process of repair,
precisely such as occurs when reunion has taken
place. This reparation may occur even when a portion