Abstract
We compared the utility of predicting the skin-epidural space distance by using various imaging modalities. Subjects comprised patients meeting the indications for lumbar epidural block who had undergone magnetic resonance imaging, radiography and computed tomography for primary disease. Skin-epidural space distances from these modalities were estimated using computed calculating functions of the imaging system. Immediately after the use of ultrasonography to estimate the distance between the skin and dura mater in short-axis and longitudinal views in the lateral position, epidural puncture was performed using a median approach. Puncture distance between the skin and epidural space was recorded. Skin-epidural space distance as estimated by each modality correlated significantly with puncture distance (p<0.001), body weight (p<0.01) and body mass index (p<0.001). In particular, ultrasound imaging showed the highest correlation to puncture distance (r=0.96, p<0.001). In conclusion, ultrasound imaging can predict skin-epidural distance with high correlation to the actual puncture distance, and it could allow adequate and safe epidural block.
