A modified procedure for lumbar intrathecal catheterization in rats

Objectives: Intrathecal catheterization and drug delivery in rats has always been a very important method for neuroscience and pain research. Although the technique has been continually improved since the first report, the experience gained over the years suggested that some defects remained unsolved. On the basis of modification of the standard epidural needle, lumbar needle, and intrathecal tube, we aimed to develop a simple and practical technique for intrathecal catheterization, which was similar to the 'needle-through-needle technique' used in combined spinal-epidural (CSE) anesthesia. Methods: For comparison, rats received intrathecal catheterization via either laminectomy at L3-4 (control group) or our modified method (modification group). The operation time, success rate, and the incidence of postoperative complication were recorded. Thermal paw withdrawal latency, mechanical paw withdrawal threshold, Rota-rod, and body weight were measured on pre-operative day 1 and postoperative day 1-3, 5, 7, 14, 21, respectively. Results: Compared with control group, our modified method was more practical to grasp and could bring about higher success rate, firmer catheters immobility, less weight loss, and minimal mortality. There was no difference between the two groups in spinal cord injury, hematoma, location of lumbar enlargement, and lateral location of the catheters tip. The procedure itself did not interfere with behavioral tests and motor coordination. Conclusion: We suggest that the modified method of intrathecal catheterization is well suitable for long-term behavior and pharmacology research on spinal cord.