Stimulating thoracic epidural placement via a lumbar approach causes significant spinal cord damage in a porcine model.

Background: Continuous thoracic epidural analgesia is a valuable and common technique for analgesia but involves risk to the spinal cord. There is significant pediatric experience safely placing thoracic epidurals via a caudal approach. The use of a stimulating catheter offers the advantage of real-time confirmation of appropriate catheter placement. We hypothesize that the tip of a stimulating epidural catheter can be reliably advanced to the thoracic epidural space with lumbar insertion in a porcine model.

Methods: This prospective experimental porcine study evaluated the feasibility of placing the tip of a stimulating epidural catheter to a predefined thoracic epidural location after percutaneous lumbar epidural access in six live pigs. After the lumbar epidural space was accessed, a stimulating epidural catheter was advanced until the targeted thoracic myotome was stimulated. The final position of the catheter in relation to the targeted location was determined by fluoroscopy. All animals were euthanized at the end of the experiment, necropsy and spinal cord histology were then performed to assess the extent of spinal cord damage.

Results: In all animals the epidural catheter tip could be accurately advanced to the targeted thoracic myotome. Gross subdural bleeding occurred in three of the six animals and deep spinal damage was observed in two of the six animals. In one animal, the catheter was placed in the subarachnoid space.

Conclusions: Accurate access to the thoracic epidural space is possible via a lumbar approach using a stimulating epidural catheter. Based on gross and histopathological examination, this technique resulted in frequent complications, including subdural hemorrhage, deep spinal cord damage, and subarachnoid catheter placement.