The Accuracy of a Handheld Ultrasound Device for Neuraxial Depth and Landmark Assessment: A Prospective Cohort Trial

This study investigated the accuracy of a wireless handheld ultrasound with pattern recognition software that recognizes lumbar spine bony landmarks and measures depth to epidural space (Accuro, Rivanna Medical, Charlottesville, VA) (AU). AU measurements to epidural space were compared to Tuohy needle depth to epidural space (depth to loss of resistance at epidural placement). Data from 47 women requesting labor epidural analgesia were analyzed. The mean difference between depth to epidural space measured by AU versus needle depth was −0.61 cm (95% confidence interval, −0.79 to −0.44), with a standard deviation of 0.58 (95% confidence interval, 0.48–0.73). Using the AU-identified insertion point resulted in successful epidural placement at first attempt in 87% of patients, 78% without redirects.