Evaluation of the skin to epidural and subarachnoid space distance in young XXXX using magnetic resonance imaging.

@entity1 @entity1337 @entity92
BACKGROUND AND OBJECTIVES: Epidural catheters placed for perioperative @entity1337 in young @entity1 confer clinical benefits but are technically challenging to insert. Approximations of the skin to epidural space depth in this population are limited to direct needle measurement and ultrasonography. Magnetic resonance imaging (MRI) is the most comprehensive imaging modality of the spine. This study aims to produce a more clinically useful formula from MRI data to estimate pediatric @entity92 . METHODS: Seventy @entity1 with normal lumbar spine MR images were enrolled. After @entity92 , linear regression was used to estimate a weight-based formula. Analysis of variance and bootstrap methods were used to evaluate this formula against 4 commonly cited formulae. The quality of predictions was evaluated using the mean absolute prediction error. RESULTS: The estimated weight-based formula as derived by MRI data is given by: skin to @entity92 (mm) = 9.00 + 0.62 * weight in kilograms. The mean absolute prediction error was 2.56 mm (95% confidence interval [95% CI], 2.12-3.04) for the new formula. Additional derived formulae are skin to dorsal dura depth (mm) = 13.52 + 0.71 * weight in kilograms (mean absolute prediction error, 2.48 mm; 95% CI, 2.00-3.03) and skin to ventral dural depth (mm) = 23.08 + 0.86 * weight in kilograms (mean absolute prediction error, 2.50 mm; 95% CI, 2.04-3.06). CONCLUSIONS: We provide the first predictive formulae, based on MRI data, for pediatric @entity92 estimation.
