An anatomic study in neonates sought to determine how close the dural sac was to the apex of the sacral hiatus, as this may lead to unintended spinal injection. Average distance in males was 10.9mm and 9.6mm in females; it increased with greater neonate length. Range was 4.9 -26.3mm.
“Anesthesiologists should be aware of the short distance between the sacral hiatus and the dural sac when performing caudal blocks, the shortest distance was 4.94 mm. Armed with this knowledge, caudal techniques should be modified to improve the safety and reduce the risk of complications, such as dural puncture.”