EPIDURAL ANESTHESIA IN CHILDREN
Epidural analgesia is commonly used in addition to general anesthesia and to manage postoperative pain. Effective postoperative pain relief from epidural analgesia has numerous benefits including earlier ambulation, facilitating weaning from ventilators, reducing time spent in a catabolic state, and lowering circulating stress hormone levels.1 Precise placement of epidural needles for single-injection techniques and catheters for continuous epidural anesthesia ensures that the dermatomes involved in the surgical procedure are selectively blocked, allowing for lower doses of local anesthetics to be used and sparing unnecessary blockade in nondesired regions. The approach to the epidural space can be at the caudal, lumbar, or thoracic level.
ANATOMY AND PHYSIOLOGICAL IMPLICATIONS
There are significant anatomical differences in children compared with adults that should be considered when using neuraxial anesthesia. For instance, in neonates and infants, the conus medullaris is located lower in the spinal column (at approximately the L3 vertebra) compared with that in adults, in whom it is situated at approximately the L1 vertebra. This is a result of different rates of growth between the spinal cord and the bony vertebral column in infants. However, at approximately 1 year of age, the conus medullaris reaches the L1 level similar to that in an adult.
In neonates and infants, the conus medullaris ends approximately the L3 level as opposed to adults, where it is located approximately at the L1 vertebra.
At approximately 1 year of age, the conus medullaris reaches the L1 level, similar to that in an adult.
The sacrum of children is also more flat and narrow compared with the adult population. At birth, the sacral plate, which is formed by five sacral vertebrae, is not completely ossified and continues to fuse until approximately 8 years of age (although it may take until 21 years of age). There is a 6% incidence of sacral atresia. The incomplete fusion of the sacral vertebral arch forms the sacral hiatus. The caudal epidural space can be accessed easily in infants and children through the sacral hiatus. Because of the continuous development of the sacral canal roof, there is considerable variation in the sacral hiatus. In young children, the sacral hiatus is located more cephalad than in older children, and the dural sac may end more caudally: at S4 in infants younger than 1 year and at S2 in older children. Therefore, because of the increased risk of accidental dural puncture, caution is warranted when placing caudal blocks in infants.
In young children, the sacral hiatus is located more cephalad than in older children, and the dural sac may end more caudally (at S4 in infants younger than 1 year).
Caution with the use caudal blocks is warranted in infants because of the risk of dural puncture.
Ultrasound (US) assessment of the neuraxial structures is less ...