The caudal canal in children: a study using magnetic resonance imaging

Abstract

The anatomy of the caudal (sacral extradural) space was studied in 41 children, using magnetic resonance imaging. The distance from the upper margin of the sacrococcygeal membrane to the dural sac, the length of the membrane and the maximum depth of the caudal space were each measured. Age, height, weight and body surface area were recorded and, using multiple linear regression (stepwise technique), equations predicting the length of the membrane and the distance between its upper margin and the lower limit of the dural sac were obtained. Wide variability limits the clinical usefulness of these equations. In all patients, the maximum depth of the caudal space was found to be at the upper margin of the sacrococcygeal membrane. No correlation was found between this maximum depth and the age, height, weight or body surface area of the child.

Anatomic Differences in the Sacral Hiatus During Caudal Epidural Injection Using Ultrasound Guidance

“…A previous study on children using magnetic resonance imaging revealed no difference in the diameter of the sacral canal between boys and girls. 20 In our study, the mean optimal angle for needle insertion was 16.7° (range, 1.1°-34.6°), and it was less than 10° in 26 of 237 patients because of a flat posterior bony surface of the sacrum. Our results are comparable with those of previous studies.…”

The caudal space in fetuses: an anatomical study

“…They attributed the high incidence of intra-osseous puncture in children younger than 10 years to the dimensions of the canal that is narrower than that of adults. The mean (range) caudal epidural space depth as noted in two studies [7,8] in children of varying age groups was 4.9 (2.0-10.0) mm and 3.5 (1-8) mm. In our study, the anteroposterior distance of the sacral canal at the apex (AP at Apx) and base (AP at Base) of the hiatus was 2.93 (1.72-4.38) and 2.09 (1.20-3.95) mm, respectively.…”

“…The depth of the caudal space at the level of the sacral hiatus, which is the level of performance of caudal blocks, was considered the primary outcome for calculating sample size, and distances in relationship to other bony landmarks and dura were the secondary outcome. A power analysis based on a previous study [8] employing the depth of caudal space at the hiatus, which was independent of age, height, weight, or body surface area, was therefore considered. Assuming the same variance (±1.79) as seen in the previous study [8], a sample size of approximately 35 was adequate to ensure a 95% confidence interval of measurement with that of the observed variance of the same measurement in the present study (±0.64).…”

“…A power analysis based on a previous study [8] employing the depth of caudal space at the hiatus, which was independent of age, height, weight, or body surface area, was therefore considered. Assuming the same variance (±1.79) as seen in the previous study [8], a sample size of approximately 35 was adequate to ensure a 95% confidence interval of measurement with that of the observed variance of the same measurement in the present study (±0.64). Our study included 39 fetuses, thus ensuring adequate sample size.…”

“…Anatomical studies of the sacrum in pediatrics have mostly been conducted on dry sacral bones [6]. Studies employing ultrasonography or other imaging modalities [7,8] have been conducted to evaluate the techniques of needle insertion rather than the safe distances for needle insertion in children, especially premature and very low birth weight infants. The best angle of needle insertion also needs evaluation in premature infants.…”