1. 2014;17;163-168The Distance from Skin to Cervical and High Thoracic Epidural Space on Chinese Adults as Read from MRI
   Prospective Study
   John P. Williams, MD, Doris K Cope, MD, Qiwu Fang, MD, Hui Wen, MD, Xiao-yan Qian, CRNA, Jian-xiong An, MD, PhD, Kechang Huang, MD, and Qianqian Zhao, MD.

BACKGROUND: A few studies on the depth from the skin to the cervical epidural space (DSES) have been reported from the United States, South Korea, Japan, and Taiwan. There are no published reports from mainland China.

OBJECTIVES: The goal of this study was to collect standard data on Chinese adults from mainland China in a large medical center with a wide geographical range of patients.

STUDY DESIGN: A prospective study.

SETTING: Department of Anesthesiology, Pain Medicine, and Critical Care Medicine, Aviation General Hospital of China Medical University.

METHODS: The survey included 410 patients. Measurements were made of DSES, the dural sac, and the spinal cord by automatic measuring ruler on transverse and sagittal images of the cervical spine at the C5-6, C6-7, C7-T1, T1-2, and T2-3 intervertebral space obtained by magnetic resonance imaging (MRI). We also obtained the width of the epidural space by measuring the distance from the (LF) to the dural sac.

RESULTS: DSES at C5-6, C6-7, C7-T1, T1-2, and T2-3, respectively, was 4.69 ± 0.84 cm, 5.14 ± 0.98 cm, 5.56 ± 1.03 cm, 5.81 ± 0.94 cm, and 5.76 ± 0.86 cm on T2W (weighted) MRIs obtained in the sagittal plane (mean ± SD). The distance at C5-6, C6-7, and C7-T1 in transverse images was 4.67 ± 0.86 cm, 5.18 ± 1.02 cm, and 5.55 ± 0.97 cm, respectively. All measured distances from the skin to the epidural space were significantly greater in men than in women. Multivariate regression analysis revealed significant partial correlation between DSES and (BMI).

LIMITATION: Limitations include the absence of healthy individuals as well as the influence of the difference in neck positioning during the MRI examination vs. active epidural puncture.

CONCLUSION: DSES varied with the cervical intervertebral level in those patients studied from the population of mainland China. The greatest DSES was noted at C7-T1 in men and T1-2 in women, and the least was at C5-6 in both men and women. DSES had a significant relationship with neck circumference and BMI in both genders. We suggest that the DSES be measured with MRI before performing epidural puncture. The lower cervical and upper thoracic intervertebral spaces appear to provide a greater margin of safety for epidural puncture.