Supraclavicular brachial plexus block
The supraclavicular block in particular has experienced a renaissance in European countries with the increasing prevalence of modern ultrasonographic devices in the field of peripheral regional anaesthesia. This has to do on the one hand with undeniable block quality, but above all with the dramatic, parallel reduction in risk profile of this method due to its direct visualization of delicate structures like the pleura and the subclavian artery. When applying a supraclavicular plexus block, the clavicula serves as a „yardstick“ for the probe. When the latter is swung at the posterior edge of the insertion of the sterocleidomastoid muscle towards the thorax or mediastinum, the viewer observes in most cases a characteristic cross-section through the brachial plexus and the structures surrounding it; the parts of the plexus – here the transitions of the trunks to the fascicles – are seen as a clustered formation lying dorsolateral to the subclavian artery. Directly below the vessel, the first rib dominates as a hyperechogenic (white) line in which ultrasound is dorsally extinguished. Standing out against this in the shape of a step, the pleura is likewise recognizable as a fine white line and is thus easily avoided during puncture.
At our institution we prefer to use the supraclavicular plexus block on the long axis and from a dorsolateral direction. A very important prerequisite of this technique is visualization of the complete needle shaft. In order to achieve complete anaesthesia of the plexus, irrigation of the deeper-lying parts is of decisive importance. They often lie directly against the first rib. After application of an initial dose of local anaesthetic in this area, the needle is retracted, and a further deposit can then be administered around the superior part of the „nerve cluster“.
Anterior and medial scalene muscles, subclavian artery, 1st rib, pleura