Distance from Dura mater to spinal cord at the thoracic vertebral level: An introductory study on local subdural geometry for thoracic epidural block

Abstract

ObjectiveTo evaluate the anatomical safety margins in relation to thoracic epidural block by analysing magnetic resonance (MR) images.MethodsThis retrospective study identified consecutive patients who underwent MR imaging of the thoracic vertebral spine. The distance from the dura mater to the spinal cord (DTC) was measured at different thoracic intervertebral levels using three different pathways as references: the ‘U’, ‘L’ and ‘M’ lines.ResultsA total of 346 patients provided MR images for analysis. The vertical DTC was the longest at the T5/6 intervertebral level (mean ± SD: 4.22 ± 1.43 mm) and the shortest at the T11/12 intervertebral level (mean ± SD: 2.51 ± 0.87 mm). The DTC was the longest on the ‘L’ line at the T1/2 and T5/6 intervertebral levels and on the ‘U’ line at the T10/11 intervertebral level. The difference in DTC between the ‘U’ and ‘L’ lines was the greatest at the T5/6 intervertebral level.ConclusionDifferences in the DTC were observed among the thoracic intervertebral levels. The variability of the safety margin according to the angle of needle insertion was the largest at the T5/6 intervertebral level.

Dura to spinal cord distance at different vertebral levels in children and its implications on epidural analgesia: A retrospective MRI‐based study

“…Although the ligamentum flavum is softer in children, loss of resistance is the most common method used to identify the epidural space at the thoracic and lumbar level in both children and adults . The anatomical dimensions related to epidural analgesia, including the dura to spinal cord distance at different vertebral levels, are not uniform . Several studies have investigated the dura to spinal cord distance in the thoracic region in adults and have reported that this particular distance was significantly greater in the middle thoracic region than at the upper and lower thoracic levels .…”

“…[5][6][7] Several studies have investigated the dura to spinal cord distance in the thoracic region in adults and have reported that this particular distance was significantly greater in the middle thoracic region than at the upper and lower thoracic levels. 5,6 The dura to spinal cord distance may be a critical factor in avoiding neurological injury caused by needle trauma after dural puncture, with a greater dura to spinal cord distance increasing the potential safety margin. 5 When compared to computed tomography (CT), magnetic resonance imaging (MRI) is a superior modality in identifying injuries to the posterior longitudinal ligament and interspinous soft tissues, and remains the method of choice for assessing spinal cord lesions and ligamentous injury.…”

“…5,6 The dura to spinal cord distance may be a critical factor in avoiding neurological injury caused by needle trauma after dural puncture, with a greater dura to spinal cord distance increasing the potential safety margin. 5 When compared to computed tomography (CT), magnetic resonance imaging (MRI) is a superior modality in identifying injuries to the posterior longitudinal ligament and interspinous soft tissues, and remains the method of choice for assessing spinal cord lesions and ligamentous injury. [8][9][10] Being the most comprehensive imaging modality of the paraspinal and intraspinal soft tissues and ligaments, the measurements obtained may be more accurate to derive the dura to spinal cord distance.…”

“…The anatomical dimensions related to epidural analgesia, including the dura to spinal cord distance at different vertebral levels, are not uniform . Several studies have investigated the dura to spinal cord distance in the thoracic region in adults and have reported that this particular distance was significantly greater in the middle thoracic region than at the upper and lower thoracic levels . The dura to spinal cord distance may be a critical factor in avoiding neurological injury caused by needle trauma after dural puncture, with a greater dura to spinal cord distance increasing the potential safety margin …”

Predictors of Intraspinal Pressure and Optimal Cord Perfusion Pressure After Traumatic Spinal Cord Injury

“…We already showed that duroplasty significantly reduces ISP after TSCI by enlarging the CSF space around the injured cord [ 12 ]. The higher ISP with conus medullaris injuries is likely related to the reduced CSF space around the conus medullaris compared with the larger CSF space higher up the spine [ 26 ]. The next factor that correlates with lower ISP is older age, perhaps because of cord atrophy in older patients, analogous to age-related brain atrophy [ 27 , 28 ].…”