[Evaluation of brachial plexus block. Comparison between supraclavicular and interscalene approach (author's transl)].

A scheme for evaluating brachial plexus block was developed, which is based on anatomical structures and which utilizes simple neurological examination techniques. It facilitates the localization of the tip of the cannula near the plexus, gives an idea of the spread of the local anesthetic in the region of the trunks and cords, gives well timed judgement on the success of the block and allows a comparison of the development of the block when using various techniques. Using this scheme, the development of the block was examined following use of the supraclavicular and interscalene approach. With the supraclavicular technique, motor as well as sensory blockade of all nerves of the brachial plexus occurred with about the same frequency; with the interscalene technique, the centre of the block affected the caudal nerves of the cervical plexus and the cranial nerves of the brachial plexus. Following both approaches, the blockade developed from proximal to distal areas, the motor blockade preceding the sensory blockade.