Abstract

Various methods have been described for the identification of the epidural space. Some of these methods used the identification of the negative pressure in the epidural space, whereas others used loss of resistance. This study was undertaken to measure the changes in electrical impedance as an electrically insulated epidural needle enters the epidural space. The study proves that there is a characteristic increase in impedance as the needle enters the epidural space. This could be a potentially useful technique in identifying the epidural space in patients who have difficult anatomy.