Supraclavicular Nerve Block

Overview: 

The Supraclavicular Nerve block is a commonly performed regional anesthetic technique at the level of the trunks of the brachial plexus to provide anesthesia and analgesia for many upper limb surgeries.

Clinical Use: 

Indications

Provision of analgesia and anesthesia for surgery of the mid-distal humerus, elbow, forearm, wrist, carpo-metacarpals and arterio-venous surgery of the upper limb (AV Fistula formation). 

Block technique

This peripheral nerve block is commonly performed with ultrasound guidance, targeting the trunks of the brachial plexus in the neck shortly before they travel under the clavicle at the level of the first rib. 

The primary ventral rami of C5 and C6 unite to form the upper trunk above the subclavian artery, C7 becomes the middle trunk and C8 and T1 unite to form the lower trunk. Both the brachial plexus and the subclavian artery lie on top of the first rib. The brachial plexus is located lateral and posterior to the subclavian artery. The subclavian vein and anterior scalene muscle are found medial to the subclavian artery. The pleura is usually found within 1-2 cm from the brachial plexus. 

The block is performed via ultrasound guidance with the patient in a supine or lateral position patient using an in-plane approach from posterio-lateral to anterio-medial. The probe is placed directly behind the clavicle and the subclavian artery, middle scalene muscle and first rib are identified. The plexus lies between the artery, middle scalene muscle and on top of the first rib. The needle is passed through the middle scalene muscle aiming for the space between plexus and first rib (the so called “corner pocket”). Local anesthetic is administered under direct vision below and if possible above the plexus. A continuous infusion catheter can be inserted to sit above the first rib between the plexus and artery.

(SA – Subclavian Artery  / DSA - Dorsal Scapular Artery/  / SM - Middle Scalene / OH – Omohyoid / R - First Rib / P –  Pleura)

Dosing in adult patients >60kg:

Single shot: 10-20 mls of 0.2 - 0.5% ropivacaine 

Infusion: 8ml/hour 0.1-0.2% ropivacaine

Block Duration

This can be as a single injection, or  continuous catheter-based  technique, depending on the duration of analgesia required. When performed with 0.5% ropivacaine, the supra-clavicular nerve block has an analgesia duration of hours 8-12 hours.

Special Considerations: 

Contraindications 

  • Absolute
    • Patient refusal
    • Coagulopathy 
    • Contralateral pneumonectomy or pneumothorax
    • Local anesthetic allergy
    • Local infection/inflammation in needle trajectory
  • Relative
    • Contralateral recurrent laryngeal or phrenic nerve paresis
    • Chest deformities
    • Dislocation or fracture of the clavicle
    • Reduced pulmonary reserve

Complications

  • Ipsilateral phrenic nerve palsy (up to 50% incidence, 20% reduction in lung function)
  • Horners Syndrome
  • Infection
  • Hematoma
  • Pneumothorax
  • Nerve damage
  • Local anesthetic systemic toxicity (LAST)
References: 

First Image - SonositeTM

Second Image - Dr Zaki Ibrahim 

Vermeylen K, Engelen S, Sermeus L, Soetens F, Van de Velde M: Supraclavicular brachial plexus nerve blocks: review and current practice. Acta Anaesthesiol Belg 2012;63:15–21.