A method for increasing the viability of the external portion of lumbar catheters placed in the spinal subarachnoid space of rats

A method for direct catheterization of the lumbar subarachnoid space has re cently been developed by Storkson et al. (1996) (J Neurosci Methods 1996;65 :167-172) that may potentially improve upon the widely used method of Yaksh and Rudy (1976) (Physiol Behav 1976;17:1031-1036). This 'catheter-through- a-needle' technique inserts the catheter between lumbar vertebrae 5 (L5) an d 6 (L6), which has been shown to reduce neurological impairment and post-s urgical deaths. However, employing this technique allows the external porti on of the chronic indwelling catheters to be easily damaged, resulting in a pproximate to 50% attrition within 4 days after surgery. Therefore, we deve loped an easy and inexpensive method for protecting the external portion of the catheter that enhances catheter viability beyond 14 days after cathete r implantation while also maintaining a low injection volume (8 mu l). More over, this modification does not significantly alter the implantation metho ds developed by Storkson et al. (1996) (J Neurosci Methods 1996;65:167-172) and allows for more optimal catheter materials to be incorporated. Chronic ally implanted catheters (n = 70) with the external portion of the catheter protected, resulted in 4% attrition 7 days after surgery and 11% attrition 14 days after surgery. Approximately 5.5% of animals implanted showed very mild and transient neurological impairment. (C) 1999 Elsevier Science B.V. All rights reserved.