Abstract: Objective: To explore the feasibility and effects of the simple "needle in needle" technique in spinal puncture.Methods: Forty patients scheduled by lower extremity and perineum operation were randomly divided into the combined spinal-epidural puncture group(control group) and "needle in needle" guided by size 9 skin needle group(observation group)(20 cases each group).Two groups were punctured between L₃ and L₄ line,and injected with 0.75% bupivacaine for 2 mL.The control group were punctured using the size 16 epidural needle into epidural space,then the size 5 spinal-epidural needle was used to puncture into subarachnoid space.The observation group were punctured using the size 5 spinal-epidural needle combined with "needle in needle" guided by the size 9 skin needle.The bevel of the needle tip was parallel to the axis of the spine.The spinal anesthesia puncture success rate,feel rate of breaking the ligamentum flava and endorachis,effects of nerve block,postoperative headache,lumbago and puncture point ache in two groups were observed.Results: The puncturing time in observation group and control group were not statistically significant(P>0.05).The difference of the breakthrough and fall feeling at the time of breaking endorhachis between two groups was not statistically significant(P>0.05).The success rates of anesthesia in two groups were 95%.The differences of the sensory block plane,onset time of sensory block and motor block between two groups were not statistically significant(P>0.05).The postural headache was not found in two groups,but 5 and 7 days after surgery the incidences of the postoperative puncture point ache and lumbago in observation group were lower than those in control group(P<0.01).Conclusions: The application of the "needle in needle" guided by the size 9 skin needle during lumbar puncture can exactly feel the breakthrough of endorhachis,the cerebrospinal fluid flows smoothly,the effect is good,the incidence of postoperative puncture point ache and lumbago are low.