Brachial plexus sonography: a technique for assessing the root level.

Abstract

Our study was intended to establish a technique to assess the level of the roots of the brachial plexus using high-resolution sonography. The skeleton of a cervical spine was examined in vitro to determine whether the vertebrae may be identified individually on sonography by means of the evaluation of their transverse processes. Then 20 healthy subjects and five patients who had undergone CT of the cervical spine were evaluated sonographically, and we attempted to identify the level of individual roots of the brachial plexus using the transverse processes as landmarks. To establish the reliability of this method, a blinded review of sonograms of the paravertebral area obtained at various levels was performed independently by three examiners. In vitro, sonography was reliable in depicting the level of the C7 vertebra because of the absence of the anterior tubercle from its transverse processes. In healthy subjects, this feature allowed us to establish the level of the roots outside the spine. In our series, the C4-C7 roots were visible sonographically in all cases, whereas the C8 and T1 levels were seen, respectively, in only 16 of 20 and eight of 20 cases. All examiners correctly identified the C7 level in the blinded review of sonograms. High-resolution sonography can reveal the level of the roots of the brachial plexus on the basis of the different morphology of the transverse processes of the vertebrae. Our study has implications for confirming the exact level of pathologic roots before surgery.