Pseudo loss of resistance in epidural space localization

Loss of resistance (LOR) is the most commonly used technique to locate the epidural space.[1] LOR to air or saline is often used and is accurate in identifying epidural space in most of the patients. False positive or pseudo-LOR can occur if the needle enters paraspinous muscles or a small cyst in the ligamentum flavum or the interspinous ligaments.[2] However, the exact incidence of false positive LOR is not reported in the literature. We encountered a false positive LOR in a patient with subcutaneous emphysema secondary to chest trauma.