▁such ▁as ▁a ▁kn ife ▁w ound , ▁damage ▁only ▁a ▁very ▁short ▁segment ▁of ▁the ▁n erve , ▁avail ing ▁for ▁direct ▁s uture . ▁In ▁contrast , ▁n erves ▁that ▁are ▁divided ▁by ▁stretch ▁or ▁cr ush ▁may ▁be ▁dam aged ▁over ▁long ▁segments . ▁These ▁n erve ▁inj uries ▁are ▁more ▁difficult ▁to ▁treat ▁and ▁generally ▁have ▁a ▁poor er ▁outcome . ▁In ▁addition , ▁associated ▁inj uries , ▁like ▁injury ▁to ▁b one , ▁mus cle ▁and ▁skin , ▁can ▁make ▁n erve ▁recovery ▁more ▁difficult . ▁The ▁level ▁of ▁injury : ▁After ▁a ▁n erve ▁is ▁rep a ired , ▁the ▁reg ener ating ▁n erve ▁end ings ▁must ▁grow ▁all ▁the ▁way ▁to ▁their ▁target . ▁For ▁example , ▁a ▁n erve ▁injured ▁at ▁the ▁w rist ▁that ▁normally ▁provides ▁sens ation ▁to ▁the ▁thumb ▁must ▁grow ▁to ▁the ▁end ▁of ▁the ▁thumb ▁in ▁order ▁to ▁provide ▁sens ation . ▁The ▁return ▁of ▁function ▁decre ases ▁with ▁increased ▁distance ▁over ▁which ▁a ▁n erve ▁must ▁grow . ▁ ▁Aut olog ous ▁n erve ▁gra ft ing ▁ ▁Currently , ▁aut olog ous ▁n erve ▁gra ft ing , ▁or ▁a ▁n erve ▁aut og raft , ▁is ▁known ▁as ▁the ▁gold ▁standard ▁for ▁clin ical ▁treat ments ▁used ▁to ▁repair ▁large ▁les ion ▁g aps ▁in ▁the ▁peri pher al ▁nerv ous ▁system . ▁It ▁is ▁important ▁that ▁n erves ▁are ▁not ▁rep a ired ▁under ▁t ension , ▁which ▁could ▁otherwise ▁happen ▁if ▁cut ▁ends ▁are