Analgesia of abdominal visceral and somatic pain.

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.

The subcostal, ilioinguinal and iliohypogastric nerves are sandwiched between the QL muscle and the psoas major muscle (PMM).

– informed consent

– monitoring

– intravenous access (and maybe sedation)

– sitting position, relaxed and slumped

– demarcate landmarks

– infiltrate with local anaesthetics

The thoracic paravertebral space is located where the intercostal muscles meet the transverse processes.

The needle is inserted with a lateral to medial in-plane approach.

Technique 1:
– inject 15-20 mL of local anaesthetic at the midpoint of the desired level
– expect blockade of 4-5 dermatomes

Technique 2:
– extend blockade by 4-5 injections of 4-5 mL

Levels:
– simple mastectomy T3-T4
– open cholecystectomy T6-T7

In the axial plane, the thoracic paravertebral space (TPS) is a triangle with the base turned towards the vertebral spine, the parietal pleura and the endothoracic fascia are the antero-lateral border and the internal intercostal membrane is the posterior border. The apex points into the intercostal space laterally. The TPS communicates with the epidural space via the intervertebral foramina, with the mediastinum antero-medially, and with the intercostal space laterally.

The internal intercostal membrane is continuous with the internal intercostal muscle (between the external intercostal muscles and the innermost intercostal muscles) laterally and the superior costotransverse ligament medially.

The TPS extends down to the vertebral body of L1.

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

Absolute contraindications

– patient refusal

– allergy to local analgesics

– neoplasia in the thoracic paravertebral space

– empyema in the thoracic paravertebral space

– infection at the site of injection

Relative contraindications

– coagulopathy/anticoagulation

– ipsilateral diaphragmatic paresis