Colour Doppler imaging of the interspinous and epidural space

Background and objective In recent studies, ultrasonic diagnostic imaging h as proved useful in the screening of the trajectory of the epidural needle. With regard to possible side-effects of spinal and epidural anaesthesia ca used by vessel injury, we aimed to evaluate the usability of Colour Doppler imaging for the depiction of interspinous vessels in prepuncture examinati on. Methods Ultrasonic examination of the L3/4 interspace area was performed in 20 volunteers. Using a 4-MHz and a 7-MHz probe with B-mode and Colour Dopp ler imaging, respectively, we compared four settings for the quality of ves sel depiction in the puncture area. Overall resolution was evaluated accord ing to the distinction of landmarks. Vascular structures were identified by pulsation (B-mode) or blood flow (Doppler). Results Colour Doppler imaging of the L3/4 interspace was unachievable usin g the 7-MHz transducer. Vessel detection was possible in 50% of the B-mode images and in all of the 4-MHz Doppler images. Vessels were perceptible fro m a diameter of 0.5 mm. Veins were the predominantly visible structures. Ov erall vessel visibility was best using 4-MHz Colour Doppler. Conclusions Prepuncture Doppler imaging can provide the epiduralist with in formation regarding the position of vessels in the needle trajectory. This might help to reduce complications in regional anaesthesia.