GAP-115
Dura to spinal cord distance at different vertebral levels in children and its implications on epidural analgesia; a retrospective MRI based study
1Beltran R, 1Veneziano G, 2AlGhamdi F, 2Azzam H, 1Tumin D, 1Tobias J, 3Wani T, 2Adam S
1Nationwide Children's Hospital, Columbus, Ohio, USA; 2King Fahad Medical City, Riyadh, Ar-riyadh, Saudi arabia; 3King Fahad Medical City/Nationwide Children's Hospital, Columbus, Ohio/riyad, USA/ saudi arabia
Background: The distance from the dura to spinal cord (DTC) is not uniform at different vertebral levels. The DTC may be a critical factor in avoiding the potential for neurological injury caused by needle trauma after a dural puncture. Greater the DTC distance is the larger the safety margin can potentially be. The objective of our study is to measure DTC at two thoracic levels T6-7, T9-10 and one lumbar level L2-3 using MRI images as it is the most comprehensive imaging modality of spine available and allows for an accurate determination of tissue spaces and distances.
Methods: 88 children under age of 8 years qualified for the study. The distance from dural side of ligamentum flavum to the posterior margin of the spinal cord were defined as DTC. Sagittal T2-weighted images of the thoracic and lumbar spine were used to measure the DTC at the T6–7, T9–10 and L1-2 interspaces. Measurements were taken perpendicular to long axis of vertebral body at each level. Pairwise paired t-tests corrected for multiple comparisons using Bonferroni method were used to identify level at which DTC was greatest. DTC at each level were compared by gender using unpaired t-tests, and correlated with age, height, and weight using Pearson’s correlation coefficient.
Results: Pairwise differences in DTC between levels reached statistical significance after correction for multiple comparisons with DTC at T6–7 in particular significantly longer than the DTC at T9–10 and the DTC at L1-2. Gender differences in DTC at each level did not reach statistical significance.
Conclusion The present study reports that the largest DTC distance is found at the T5-6 level, and the shortest DTC distance at the L1-2 level, hence there appears to be substantially more space in the dorsal subarachnoid space at the thoracic level. The risk of spinal cord damage resulting from accidental epidural needle advancement may be greater in the lumbar region due to the dorsal location of the spinal cord in the vertebral canal compared to the thoracic region.
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