Magnetic Resonance Imaging of the Caudal Epidural Space: Implications for the Clinical Practice Regional Anesthesia in Infants and Children

Abstract

Background: Neuraxial blockade involving the lumbar and caudal space spine is commonly employed in pediatric anesthesia. Although the incidence of complications is low, the consequences including total spinal block, spinal cord or nerve injury, and post-dural puncture headache may be significant. Information regarding the vertebral level at which the spinal cord terminates and the distance from the skin to the end of the dural sac (DS) may guide clinical practices. The present study measures various distances of the lumbar and caudal epidural space in children using magnetic resonance imaging (MRI).

Methods: This retrospective study analyzed sagittal MR images of the lumbar spine of children ranging in age from birth to 8 years. Measurements included the level of termination of the spinal cord and DS; the distance from the end of the spinal cord to the end of the DS, the sacrococcygeal membrane (SCM), and the skin; and the distance from the end of the DS to the SCM and the skin. Descriptive statistics included mean, median, range, standard deviation, interquartile range, and confidence intervals.

Results: The study cohort included 91 patients, ranging in age from birth to 8 years. There was no significant difference in the variables between males and females. Using patient age, height, weight and body surface area (BSA) as variables, there was a statistically significant relationship of age with all measured parameters. There was significant interpatient variability despite grouping the data in small groups with regards to age, height, and weight. The variance inflation factor (VIF) between age and BSA was 3.51, not indicative of any collinearity issues.

Conclusion: The wide variability in measurements among studied groups, despite dividing them into smaller groups with regards to age, weight or height, would make it difficult to develop unifying formulas based on physical and age characteristics. The spinal cord ended at L₁ in children more than 12 months of age, which contradicts earlier studies suggesting its lower position at L_2-3. The terminal end of the spinal cord was found at L₂ in the majority of the patients less than 12 months of age.

Int J Clin Pediatr. 2022;11(1):2-8
doi: https://doi.org/10.14740/ijcp480