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

The infraclavicular brachial plexus block first described by Raj et al. was supposed to anesthetize all the main peripheral nerves of the brachial ple xus without the risk of pneumothorax. However, in performing the block, we have had difficulties finding the nerves at the cord level. Therefore, we q uestioned whether the recommended needle direction (the "Raj line") guides the needle close enough to the cords. We therefore designed an anatomic stu dy to answer this question and to assess the risks of entering the pleura a nd axillary vein. Ten volunteers were examined noninvasively in an open mod el 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 sh ortest distance to the pleura was only 10 (0-27) mm, and in one case, it hi t the pleura. Finally, the Raj line's distance to the axillary vein was als o short, 11 (0-18) mn. We conclude that a modification of the method is nec essary to guide the needle closer to the cords and further away from the pl eura and the axillary vein. A more lateral needle insertion seems beneficia l. Implications: Using a magnetic resonance scanner, the anatomical basis o f Raj's infraclavicular met,hod for brachial plexus blockade was examined i n volunteers. The results show that the method should be modified to make i t more precise and to provide less risk of complications.