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Ultrasound-guided interscalene nerve block

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Positioning of the patient for purposes of a block corresponds by and large to the conventional Meier technique. The key structures are easiest to identify from a supraclavicular view of the brachial plexus (as shown). After identification of the subclavian artery, which is surrounded dorsolaterally by the various parts of the brachial plexus in a half-moon or cluster formation, the probe is turned in a cranial direction, showing on the screen the reorganization of the supraclavicular trunks and/or fascicles back to the cervical roots of the plexus. In the classical case, at least C5-C7 are clearly seen to line up as a hypodense „string of pearls“ between the anterior and medial scalene muscles.


The Technique

In our department the interscalene block is carried out in most cases as a continuous technique with the aim of advancing a catheter in the ideal situation tangentially to the nerve roots. For this reason puncture is carried out on the short axis, taking care not to touch the nerve roots directly with the exploratory needle. The application and/or distribution of the local anaesthetic around the above-mentioned „string of pearls“ is of decisive importance.

 

Note: This block characteristically takes effect extremely quickly; surgical tolerance is reached in only a few minutes.

 

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Sonoanatomic Landmarks

Sterocleidomastoid muscle, anterior and medial scalene muscles, nerve roots of the brachial plexus

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