ANATOMY OF THE NORMAL BRACHIAL-PLEXUS REVEALED BY SONOGRAPHY AND THE ROLE OF SONOGRAPHIC GUIDANCE IN ANESTHESIA OF THE BRACHIAL-PLEXUS

OBJECTIVE. The purpose of this study is to describe the sonographic ap pearance of the normal brachial plexus and to evaluate the use of imag ing guidance for brachial plexus anesthesia. SUBJECTS AND METHODS. Twe nty adults requiring upper limb surgery underwent sonography with a hi gh-frequency transducer to identify the brachial plexus at the intersc alene (n = 16) and supraclavicular (n = 4) regions. Catheters for brac hial plexus anesthesia were placed using sonographic guidance and eval uated using radiography and CT after injection of contrast material. T he success of the neural blockade and surgical anesthesia was assessed . General anesthesia was chosen preoperatively or used for supplementa tion if blockade was incomplete. RESULTS. The brachial plexus appeared as three discrete rounded hypoechoic nodules between the scalenus ant erior and medius muscles on transverse sonography at the lower cervica l (C6) region, representing the trunks in sagittal oblique section. A cluster of hypoechoic nodules corresponding to the divisions was seen cephalad to the subclavian artery on sagittal scans of the supraclavic ular region. Radiography was used to verify correct catheter placement ; the brachial plexus sheath appeared as a tubular area of contrast ma terial in the neck that was well circumscribed in patients who had sup raclavicular injections of contrast material and corrugated in those w ho had interscalene injections. CT scans showed contrast material spre ad around the scalenus muscles in most patients with interscalene inje ctions. Successful neural blockade at 20 min and postoperative analges ia were achieved in all patients. Surgical anesthesia was achieved in nine of 15 patients. Five patients chose general anesthesia before sur gery and therefore did not have surgical anesthesia assessed. CONCLUSI ON. High-resolution sonography can show normal brachial plexus anatomy and facilitate catheter-based brachial plexus anesthesia without comp lications.