Over the last 20 years or so, ultrasonography has also made its way into the field of regional anaesthesia and attracts considerable interest there. The frequency of its clinical use is growing exponentially - as is also the number of publications on this topic. This growth has been made possible primarily by technical improvements in the area of ultrasonic devices, which today can provide a very detailed image of superficial structures. This is accomplished by means of high-frequency, low-distortion probes.
Industry has attempted to keep pace with racing developments in the field of ultrasonography by making needles out of special materials which, when correctly used, show up with an even sharper outline in the ultrasonographic image. Depending on the manufacturer, various procedures are used here. However, socalled ‚atraumatic‘ needles should always be used in ultrasonographic guidance of blocks as well. This is especially true when the user is less practiced and – as experience has shown – generally has more difficulty at first in visualizing the tip of the needle.
A striking difference here from conventional, ‚landmark‘-based puncture techniques is that the anaesthetist in charge has a much greater range of „freedom“ in selecting the access paths to the target structures, i.e. the nerves. However, this does not relieve him of responsibility for carrying out an intensive investigation of the respective (cross-sectional) anatomy of the region in question. Only under this premise and in combination with corresponding coordinative and manual dexterity can ultrasound contribute to minimum-risk puncture with little duress for the patient. Attention can then be directed flexibly to the individual anatomic features rather than to external landmarks.
Combined Procedure (“Dual Guidance“)
Time and again the question arises whether in the long run ultrasound will ring in the end of the era of electrical nerve stimulation. In our view, this is neither desirable nor to be expected for two reasons.