Abstract: Objective: To introduce a new design needle and a device of microcatheter protection for lumbar intrathecal catheterization in rats,and evaluate its feasibility and effectiveness.Methods: Sixty pathogen-free adult male Sprogue-Dawley rats were randomly divided into two groups(n=30 in each group), the control group (group C) and the modification group(group M). The traditional puncture device, 20G needle, was used in the group C without extemal shielding protection. The new design puncture needle and the microinjection cock were used in the group M. All rats were assessed for motor function on postoperative. The motor function was evaluated 1 day afteroperation. Lidocaine was injected in the catheter at 1st,3rd,7th,14th,21st day post-catheterization, methylene blue was injected in intrathecal at 30th day after operation, and the catheter location was observed. The paw withdrawal threshold(PWT) was measured at 1st,3rd,7th,14th,21st,30th day after operation, open-field test was tested at preoperative and one week postoperative for the purpose of evaluating the autonomous behavior of rats. Results: About motor function:level Ⅰ 75.9%,level Ⅱ 20.7%,level Ⅲ 3.4% in group C, and level Ⅰ 96.7%,level Ⅱ 3.3% in group M, Compared with group C,group M had higher percentage of the level Ⅰ in motor function (P＜0.05);Lidocaine test and methylen blue location showed that each one case of catheter was removed on the 14th and 21st day after intubation in group C, and total four cases were removed till the 30th day, while all catheters were in normal location in group M. There was significant difference between two groups in protection of the extemal portion of catheter(P＜0.05); The time of intrathecal injection in group M was only 1 minute, and it spent more than 3 minutes in group C. Compared with group C,the time of intrathecal injection is significantly shorter in group M(P＜0.01);PWT was reduced to the lowest on the third day after catheterization, and there was significant difference compared with preoperative(P＜0.05), PWT recovered on the 7th day and there were no significant difference between two groups; Compared with preoperative, there was no significant difference in the parameters of the group M in the open field test, neither between two groups. Conclusion: The new design puncture needle by its less injury and higher efficiency can be used in intrathecal catheterization. The microinjection cock is reliable and convenient for repeat injection with a perfect protection function of the external portion of catheter, meanwhile it has no impact on rats’ autonomous behavior so that it is worthy of further promoting.

Key words: intrathecal catheterization, rat, spinal subaraehnoid space, pain, microinjection