ABSTRACT
If radiographic verification of the placement of the catheter is desired, the patient should be sedated or anesthetized and the procedure performed on the table top of an X-ray machine. Following preparation, the animal is draped so only a small area of skin is exposed over the lumbosacral space. A Touhy needle is introduced through the skin and directed toward the lumbosacral junction. The needle should be directed cranioventrally rather than perpendicularly to facilitate passage of the catheter. The length of catheter needed is estimated by measuring the distance from the lumbosacral space rostrally to the desired site of action on the spinal cord and nerves, allowing for the distance from skin to spinal canal, and some extra length for later positioning. Migration of local anesthetic to the cranial thoracic or cervical spinal cord can cause motor blockade to the respiratory muscles and block sympathetic nerves responsible for regulation of cardiovascular function.
