Franklin Andrew D, Lorinc Amanda N, Shotwell Matthew S, Greene Elton B, Wushensky Curtis A
From the Departments of *Anesthesiology, †Biostatistics, and ‡Radiology, Vanderbilt University Medical Center, Nashville, TN.
Reg Anesth Pain Med. 2015 May-Jun;40(3):245-8. doi: 10.1097/AAP.0000000000000234.
Epidural catheters placed for perioperative analgesia in young children 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 epidural depth.
Seventy children with normal lumbar spine MR images were enrolled. After determination of epidural depth, 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.
The estimated weight-based formula as derived by MRI data is given by: skin to epidural depth (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).
We provide the first predictive formulae, based on MRI data, for pediatric epidural depth estimation.
用于小儿围手术期镇痛的硬膜外导管具有临床益处，但插入技术具有挑战性。该人群中皮肤至硬膜外间隙深度的近似值仅限于直接针测量和超声检查。磁共振成像（MRI）是脊柱最全面的成像方式。本研究旨在从MRI数据中得出更具临床实用性的公式，以估计小儿硬膜外深度。
纳入70例腰椎MRI图像正常的儿童。确定硬膜外深度后，采用线性回归估计基于体重的公式。使用方差分析和自助法将该公式与4个常用公式进行比较评估。使用平均绝对预测误差评估预测质量。
由MRI数据得出的基于体重的估计公式为：皮肤至硬膜外深度（mm）=9.00 + 0.62×体重（千克）。新公式的平均绝对预测误差为2.56 mm（95%置信区间[95%CI]，2.12 - 3.04）。另外得出的公式为皮肤至硬脊膜背侧深度（mm）=13.52 + 0.71×体重（千克）（平均绝对预测误差，2.48 mm；95%CI，2.00 - 3.03）以及皮肤至硬脊膜腹侧深度（mm）=23.08 + 0.86×体重（千克）（平均绝对预测误差，2.50 mm；95%CI，2.04 - 3.06）。
我们基于MRI数据首次提供了用于小儿硬膜外深度估计的预测公式。
