Magnetic resonance imaging demonstrates lack of precision in needle placement by the infraclavicular brachial plexus block described by Raj et al.

UNLABELLED The infraclavicular brachial plexus block first described by Raj et al. was supposed to anesthetize all the main peripheral nerves of the brachial plexus without the risk of pneumothorax. However, in performing the block, we have had difficulties finding the nerves at the cord level. Therefore, we questioned whether the recommended needle direction (the "Raj line") guides the needle close enough to the cords. We therefore designed an anatomic study to answer this question and to assess the risks of entering the pleura and axillary vein. Ten volunteers were examined noninvasively in an open model magnetic resonance scanner. The Raj line deviated greatly from a defined location on the cords by a mean of 26 (range 14-39) mm, always caudad, and posterior to the target in nine cases. Further, the needle trajectory's shortest distance to the pleura was only 10 (0-27) mm, and in one case, it hit the pleura. Finally, the Raj line's distance to the axillary vein was also short, 11 (0-18) mm. We conclude that a modification of the method is necessary to guide the needle closer to the cords and further away from the pleura and the axillary vein. A more lateral needle insertion seems beneficial. IMPLICATIONS Using a magnetic resonance scanner, the anatomical basis of Raj's infraclavicular method for brachial plexus blockade was examined in volunteers. The results show that the method should be modified to make it more precise and to provide less risk of complications.