Usefulness of epidural nerve stimulation to confirm epidural catheter placement

An epidural catheter must be placed in epidural space correctly to give sufficient epidural anesthesia for patients. Recently, as a technique to confirm the catheter placement, electrical stimulation of epidural nerve using an inserted epidural catheter was introduced. This study was conducted to evaluate the reliability of this simple technique in 13 patients. Immediately after an epidural catheter (19 G Arrow Flextip Plus) was placed, an adapter with electrode (Arrow-Johans ECG Adapter) was attached to its connector and nerve stimulation was performed using a peripheral nerve stimulator (1 Hz, 10 mA). Catheter placement was judged to be correct by both presence of muscle contraction in response to stimulation and occurrence of analgesia after the administration of a local anesthetic. In 5 patients, additional roentgen examinations were performed to identify the positions of catheters. In all patients except one, muscle contraction was observed by stimulation, and analgesia was confirmed in all patients after the injection of an anesthetic. X-ray examinations revealed that the tip of catheter placed at the vertebral level corresponded with the spinal segmental level where muscle movement occurred. Our study demonstrates that nerve stimulation can be a reliable method to confirm epidural catheter placement. Our results also suggest that the position of catheter tip can be estimated easily using this technique.