A new approach for brachial plexus block under fluoroscopic guidance

We performed the subclavian perivascular approach to the brachial plexus us ing contrast medium to confirm the location of the tip of the needle and th e spread of the injected solution to obtain a high success rate and to mini mize the risk of pneumothorax. Review of the cases led to the hypothesis th at the solution injected inside the costal attachment of the middle scalene muscle spreads into the interscalene space. Because of the difference in t he placement of the tip of the needle using our technique and the supraclav icular approach, including the subclavian perivascular approach, we termed our technique the supracostal approach. We conducted the present study to e stablish the supracostal approach by proving this hypothesis. A total of 17 3 blocks in 149 adult patients were studied. Eighty-four blocks in 74 patie nts were achieved by using the supracostal approach with contrast medium. T he needle was inserted 1 cm lateral to the palpated subclavian artery and 1 -2 cm above to the clavicle to touch a specific part of the first rib, whic h we believed to correspond to the inside of the costal attachment of the m iddle scalene muscle. After injecting the anesthetic solution with contrast medium, radiographs were obtained for each block, while computed tomograph ic (CT) studies were performed for five blocks. Five blocks in five patient s were achieved by using the subclavian perivascular approach with contrast medium and both radiographs and CT studies. In addition, the anatomical di fference between the two approaches was evaluated in five adult cadavers. B ased on these studies, we determined the proper part of the first rib that corresponded to the inside of the costal attachment of the middle scalene m uscle. Eighty-four blocks in the remaining 70 patients were performed with the supracostal approach without contrast medium. Of the 84 blocks with con trast medium, 80 (95%) produced successful blockade defined by sensory and motor examination. The radiological studies showed that, with the supracost al approach, the injected solution, which spread from the middle scalene mu scle into the interscalene space, did not spread below the first rib. Howev er, with the subclavian perivascular approach, the solution was confined wi thin the perineural sheath and spread below the first rib to the axilla. Th e anatomical studies could explain this difference, revealing that the peri neural space of the brachial plexus is not identical to the interscalene sp ace. There was no failure in the 84 blocks performed with the supracostal a pproach without contrast medium after we determined the proper part of the first rib. We conclude that the supracostal approach to the brachial plexus is reliable, easy to perform, and associated with a low complication rate. Implications: A new fluoroscopically guided approach for brachial plexus b lock has been established on the basis of anatomical and radiological studi es to be reliable, easy to perform, and associated with a low complication rate.