Background: After the interscalene block, albeit on very few occasions, the contralateral block also occurs via diffusion concurrently with the ipsilateral block. We would like to report a case in which bilateral sensory and motor block occurred following interscalene block.
Case Report: A 39-year-old female with distal fracture of the left radius after a slipping trauma was admitted to our hospital. A left interscalene block was placed using the technique described by Winnie. A nerve stimulator confi rmed needle placement by stimulating plexus cervicobrachialis with 0.5 mA, and than 20 ml 2% lidocaine and 15 ml 0.5% bupivacaine was injected in increments. Twenty fi ve minutes after local anesthetic injection, a complete sensory and motor block was present in the left upper limp. Surprisingly, after 10 minutes, limited only by the areas that were innerved by brachial plexus, complete sensory and motor block of the right upper limp was recognized. The duration of operation was two hours. Sensory and motor block on the right side wore off one hour and on the left side wore off three hours.
Conclusions: We concluded that spread of local anesthetic to the opposite side through the midline connective tissue septum behind the prevertebral fascia does not depend upon the volume of local anesthetic but the location and the size of the leak in the midline connective septum tissue; yet these factors dominates the quality, quantity, onset and the duration of the brachial plexus block on contrlateral side.

Keywords: bilateral, interscalene block