Ultrasound Evaluation of the Depth of the Epidural Space at T3-T4 Level - Abstract
Thoracic epidural anesthesia is an important and widely applied clinical procedure, but the injection depth poses a clinical challenge. The anatomical characteristics of the thoracic spinal column demand extreme caution at performing this technique. Ultrasound is a valuable method that adds to success in anesthetic blockages. However, literature registry on the ultrasound distance from skin to epidural space (epidural depth) at the thoracic level is scarce.
The objective of this study is to measure the epidural depth at the level of interspace T3-T4.
A cross-sectional study with 48 non-obese and healthy volunteers, being 20 men and 28 women was carried out. Measurements of epidural depth were accessed and correlated to anthropometric variables, gender and age of the subjects. The quality of the obtained ultrasound images was also inspected and associated to the study.
Means epidural depth values were: 3.60 + 0.5 cm and 3.54 + 0.6 cm on the transverse and right sagittal oblique planes, respectively. The obtained distances were positively correlated to weight in both men and women, to height in men and to body mass index (BMI) and age in women. Eighty three percent of the ultrasound images on transverse plan were classified as conclusive and 16.7 % inconclusive, whereas 77.1 %
on right sagittal oblique plan were conclusive and 22.9 % inconclusive.
Epidural depth was 3.60 cm and 3.54 cm on transverse and right sagittal oblique planes, respectively. The index of conclusive images found in this study was higher than the ones reported in the literature.