Percutaneous chronic epidural catheterization in the rabbit

Background. Although several epidural catheterizations in small animals have been reported, all of them were performed surgically and no percutaneous method has been reported. We have established a technique for percutaneous chronic epidural catheterization in rabbits. Methods. Following pentobarbital anesthesia, the animals (n=15) were fixed in a prone position using a fixing apparatus. A 19-gauge Tuohy needle was inserted in the lumbar region at an angle of about 30° to the skin with the paramedian approach and advanced into the epidural space with the loss-of-resistance method. A 23-gauge Nylon catheter was advanced cephalad in the epidural space and the distal tip was extruded from the neck following the subcutaneous tunnelling. The effects of 0.5 ml of 1% lidocaine injected through the catheter were observed for 10 days. Results. No behavioral or neurological abnormalities were observed after the catheterization except for one case of catheterization in the epidural vessel. Motor paralysis of hind-limbs became manifest at 1–2 min after injection of 0.5 ml of 1% lidocaine through the catheter, and lasted 15–25 min. Autopsy revealed that the catheter was located in the lumbar epidural space in all animals and the distribution of methylene blue was consistent with that of lidocaine. Conclusion. This rabbit model can be used to investigate the effects of epidurally administered drugs.