10 – Sonoanatomy of the thoracic paravertebral block

The pleura is visible as a hyperechoic line with “pleura sliding” in synchrony with respiration. This is different from the rib that has an anechoic acoustic shadow and no lung sliding.

The needle is advanced with real-time in-plane technique and aims at the triangular thoracic paravertebral space underneath the internal intercostal membrane and the needle tip should be placed right next to the anechoic acoustic shadow of the transverse process. A “pop” is often felt when the needle tip penetrates the internal intercostal membrane.

After assuring negative aspiration for blood 15-20 mL of local anaesthetic is injected. The TPS is seen to expand and push the pleura downwards. The local anaesthetic should be injected into the anterior part of the TPS anterior to the endothoracic fascia. This assures that the local anaesthetic spreads longitudinally inside the TPS and that sympathectomy is produced.