Ultrasound-Guided Greater Auricular Nerve Block: A Pilot Study for Pain Management in Post-Auricular Injection

Post-auricular procedures in aesthetic surgery, including hyaluronic acid filler correction for "lying ears," otoplasty, and cartilage harvest, traditionally require direct local infiltration. This technique causes significant pain and tissue distortion that may compromise surgical precision. The greater auricular nerve (GAN) provides primary sensory innervation to the post-auricular region and represents an accessible target for regional blockade. This study evaluates the efficacy of ultrasound-guided GAN block for providing anesthesia to the post-auricular region.

This prospective, self-controlled, single-blind study enrolled 20 healthy volunteers. Each participant received an ultrasound-guided GAN block on one random side and a sham saline injection on the contralateral control side. Outcomes included sensory mapping with 10-g Semmes-Weinstein monofilament, quantitative pressure pain thresholds using a digital Newton meter at three anatomical points (earlobe, posterior concha, post-auricular sulcus), and visual analog scale (VAS) scores during simulated procedural injections . Block duration was also documented.

The GAN block produced consistent anesthesia of the earlobe, post-auricular sulcus, and lower two-thirds of the posterior ear while sparing the conchal bowl and upper helix. Pain thresholds on the blocked side reached the maximum measurable force (3.0 N) at all test points in all 20 subjects, significantly exceeding baseline values (p < 0.02). Mean VAS scores during simulated injections were 1.15 ± 0.75 on the blocked side versus 4.1 ± 0.91 on the control side (p < 0.02), representing a significant reduction in perceived pain. Mean block duration was 4.47 ± 0.55 hours. No complications occurred.

Ultrasound-guided GAN block with minimal anesthetic volume provides profound, reliable post-auricular anesthesia without tissue distortion. This technique significantly ameliorates injection pain at minimal cost, preserves surgical landmarks for precision procedures, and provides extended postoperative analgesia. This pilot study supports the feasibility of the technique and provides a rationale for future patient-based trials.

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