1 – Probes

Basic UGRA can be performed solely with a high-frequency linear probe

Advanced UGRA requires high-frequency linear as well as low-frequency curved array probes

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Advanced UGRA mandates a low-frequency curved array probe for various blocks

2 – Electrical nerve stimulation

Basic UGRA can be performed only with ultrasound without supplemental electrical nerve stimulation (ENS) technique

Advanced UGRA requires a combination of ultrasound and ENS for various blocks

ENS is obsolete for most blocks for the purpose of nerve localisation. However, sometimes peripheral nerves are not visible with ultrasound and ENS can be useful in order to confirm nerve identity

Generally, the main purpose of ENS is a safeguard in order to assist avoiding accidental piercing of peripheral nerves and intraneural injection

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A modern electrical nerve stimulator

3 – Colour Doppler mode

Colour Doppler mode can be very useful to identify blood vessels surrounding deeply located target nerves

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Colour Doppler signal from the inferior gluteal artery (red spot) when doing a parasacral parallel shift approach to the sacral plexus (red arrow)
L = left, M = medial