US Guided Regional Anesthesia

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ENS is obsolete for most blocks for the purpose of nerve localisation; however, sometimes peripheral nerves are not visible with ultrasound and ENS can be useful in order to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

Image missing — 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

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

1 – Learning objective

The learning objective of the advanced ultrasound guided regional anaesthesia program is to obtain in-depth sonoanatomical theoretical knowledge about the selected advanced nerve blocks.

7 – References

4 – Scanning technique for the SPEDI approach

Place the patient supine.

Place the low frequency curved array probe approximately 10 cm below the inguinal ligament in the femoral triangle and visualize the sciatic and saphenous nerves (see second next page).

Insert the needle from the lateral end of the probe. First advance the needle tip to the sciatic nerve and then direct it to the saphenous nerve subsartorially just lateral to the femoral artery (see second next page)

6 – Sonoanatomy: SPEDI

First the needle is advanced to the sciatic nerve between the gluteus maximus and adductor magnus. Then the needle is redirected to the saphenous nerve lateral to the femoral artery below the sartorius muscle in the femoral triangle.

5 – Sonoanatomy: Subgluteal view with a high-frequency linear probe

The needle is advanced from lateral to medial while avoiding piercing the posterior femoral cutaneous nerve.

3 – Scanning technique for the subgluteal approach

Place the patient in the lateral position

Place the low-frequency curved array probe in the gluteal crease. A linear probe can be used in lean patients

Visualize the target sciatic nerve (see next page)

Insert the needle from the lateral end of the probe with in-plane technique

Advance the needle tip to the target sciatic nerve

Inject 10-15 mL of local anaesthetic until complete perineural spread is obtained

2 – Anatomy of the sciatic nerve in the subgluteal space

In the subgluteal space the sciatic nerve is sandwiched between the adductor magnus anteriorly and the hamstrings (long head of the biceps femoris laterally and the semitendinosus/semimembranosus medially).