Epidural catheter placement in the rabbit--a novel approach

Using a pediatric epidural set and through caudal approach, we studied a relatively non-invasive technique for epidural percutaneous cannulation in rabbit for chronic laboratory investigations.

Ten rabbits weighing over 3 kg were chosen and anesthetized with intravenous pentothal. A #19 pediatric Touhy needle and 23-gauge catheter were used for cannulation. Via the caudal approach, the epidural space could be located either by a "give" or with a technique of loss of resistance. Under fluoroscopy the catheter was tested with the injection of contrast medium for the confirmation of the proper position. The catheter was then tunneled under the skin and secured. The rabbits were kept in standard care for 4 weeks and then sacrificed by intraperitoneal pentothal overdose. A pathologist blinded to the study carefully examined the whole spine by laminectomy from cervical to coccyx and the findings were recorded.

With the injection of contrast medium, the final position of the catheter was validated by fluoroscopy in all rabbits. Two rabbits sustained immediate complications from the contrast medium and/or technique, of which one died shortly after the contrast medium injection and the other had weakness of the hind legs for a week. At sacrifice, all the catheters were found in good position. Two had hematoma associated with signs of trauma. One developed subcutaneous abscess. One had stitch infection of skin.

Percutaneous cannulation of epidural catheter is possible in the rabbit. Complications could be ameliorated by prudent approach in a skillful hand. It can be a reasonable model for the study of centrally administered medicines and their neurotoxicity.