How is an auricular block performed, including anesthetic choice, dosage, injection sites, and adjunct medications?

Auricular Block Procedure

For auricular procedures, perform a regional nerve block targeting the great auricular nerve (GAN) and auriculotemporal nerve using lidocaine 1% with epinephrine (buffered with sodium bicarbonate), with ultrasound guidance when available for improved success rates.

Anesthetic Choice and Safety

The primary anesthetic should be lidocaine 1% with epinephrine, as epinephrine use on the ear is explicitly safe and recommended with Level A evidence 1. This contradicts historical dogma about terminal vessel areas—extensive research confirms no cases of necrosis occur with epinephrine use on the ear, and it provides faster onset, longer duration, and reduced bleeding 1.

Key Anesthetic Modifications:

• Buffer the lidocaine with sodium bicarbonate to significantly reduce injection pain (Level A recommendation) 1
• Use the lowest effective epinephrine concentration (typically 1:100,000 or 1:200,000) 1
• Alternative: Bupivacaine 0.5% for longer duration, though onset is slower 2, 3
• Mepivacaine 1% is effective but requires minimal volumes (as low as 0.1 mL per injection site) 2

Injection Sites and Technique

Anatomical Targets:

The ear receives sensory innervation from multiple nerves requiring a multi-point approach:

1. Great Auricular Nerve (GAN) Block - Primary target

• Location: Posterior border of sternocleidomastoid muscle, approximately 6-7 cm inferior to the external auditory canal
• Coverage: Helix tail, antitragus, lobule, mandibular angle, and skin over mastoid 2, 3
• Does NOT cover: Antihelix and concha 2

2. Auriculotemporal Nerve Block - Anterior coverage

• Location: Anterior to the tragus, superficial to the temporomandibular joint
• Coverage: Anterior-superior portions of the auricle

3. Lesser Occipital Nerve - Posterior-superior coverage

• Location: Along posterior border of sternocleidomastoid, superior to GAN

4. Auricular Branch of Vagus Nerve - Ear canal

• Location: Within the external auditory canal (if canal anesthesia needed)

Dosage and Volume

• Total volume: 3-5 mL typically sufficient for complete auricular anesthesia 3
• Per injection site: 0.5-1.5 mL per nerve 2, 3
• Ultrasound-guided technique: As little as 0.1 mL can achieve successful blockade 2
• Maximum safe lidocaine dose: 4.5 mg/kg (with epinephrine: 7 mg/kg)

Ultrasound Guidance vs. Landmark Technique

Ultrasound guidance is preferred when available for several advantages:

• Real-time visualization of the GAN increases block success from ~75% to nearly 100% 2, 3
• Dramatically reduces required anesthetic volume 2
• Allows in-plane needle guidance for precise deposition 2

Landmark-based technique remains acceptable and is described as "easy to perform" with injection sites distant from major vascular structures 4. This is practical for emergency settings without ultrasound access.

Adjunct Medications

Recommended:

• Sodium bicarbonate: Mix 1:10 ratio (1 mL bicarbonate to 10 mL lidocaine) to reduce injection pain 1

NOT Recommended:

• Hyaluronidase: Insufficient evidence for routine use; contraindicated in bee venom allergy 1
• Mixing multiple local anesthetics: No proven benefit over single agent, and pharmacokinetic rationale is flawed 1, 5
• Steroid additives: Risk of precipitation and embolization; only consider for chronic neuralgia cases 6, 5

Clinical Pitfalls and Caveats

Common failures:

• Incomplete coverage of antihelix and concha with GAN block alone—requires additional nerve blocks 2
• Auriculotemporal nerve block has lower success rates (only 6% in one study) 7
• Inadequate wait time: Allow 5-10 minutes for full onset

Safety considerations:

• Avoid excessive volumes that could cause tissue distortion
• Injection sites are distant from major vessels, making this a low-risk block 4
• Monitor for inadvertent auriculopalpebral nerve block causing temporary eyelid ptosis 7

Special populations:

• Pregnancy: Safe in small amounts; delay elective procedures to second trimester when possible 1
• Cardiac disease: Safe in stable patients; consult cardiology if uncertain 1

Expected Outcomes

• Onset: 5-10 minutes for lidocaine; 15-20 minutes for bupivacaine
• Duration: 60-120 minutes with lidocaine/epinephrine; up to 4-6 hours with bupivacaine 2, 6
• Success rate: 75% with landmark technique, approaching 100% with ultrasound guidance 2, 7
• Immediate pain relief reported in emergency department case series 4