Electrical nerve stimulation and locoregional anesthesia: New modalities

Electrical nerve stimulation (ENS) is a proven modality for ascertaining close needle-to-nerve proximity. ENS has been used for decades and has been associated with high success rates and extremely low complication rates. Ultrasonographic (U/S) guidance has been used increasingly to assist in the placement of peripheral and plexus nerve blocks. U/S guidance allows for real-time imaging of the needle, targeted nerve or nerves, and other relevant anatomical structures that are in close proximity. Each modality alone has distinct advantages as well as limitations. Each can be used alone for many regional blocks or the two can be combined, more optimally, to take advantage of the positive attributes of both techniques. Both ultrasonographic imaging equipment and techniques devices used for electrical nerve stimulation continue to evolve, improving success and user friendliness.