Abstract:Objective: To investigate the pathologic influence of epidural anesthesia on nerve root when it was injured. Methods: Thirty rabbits with segmental epidural catheter were randomly divided into five groups: group L(n=6),group R(n=6),group S(n=6),group SL(n=6),and group SR(n=6). Lidocaine and Ropivacaine were injected respectively into epidural space in group L and group R. A lateral nerve root was artificially injuried at the same interspace where the epidural catheter was placed in group S. Lidocaine and Ropivacaine were injected respectively into epidural space in group SL and group SR after a lateral nerve root was artificially injuried as group S.The local anesthetics were injected every 12 hours at every group except group S,and continued two day.After seven days rabbits were put to death for advanced investigation. Results:There are obvious degeneration of the organelles and demyelination of nerve roots in group SL and group SR. Conclusions: Intrathecal block should be used cautiously when nerve root is injuried.