(15) Identifying Great Auricular Nerve via Bony Landmarks: A Cadaver Study

Abstract: Abstract
Great Auricular Nerve (GAN) is the most commonly sacrificed nerve during rhydectomies due to anatomical variation and lack of a reliable landmark1. Even though quality of life does not decrease, surgeons should strive to avoid iatrogenic injury to the nerve. The aim of this study is to utilize two bony landmarks for the Great Auricular Nerve to determine which if there is a reliable, bony anatomical landmark during surgery, specifically calculating the ratio at which the angle of the mandible (gonion) and tip of the mastoid process bisect GAN. Fourty six cadavers were dissected to expose the GAN along the angle of mandible (AOM), Erb’s point, and mastoid process. Via two independent observers, the ratio was measured as the distance between AOM and mastoid process divided by the AOM to GAN along the same angle. The mean ratio was 0.457 with a standard deviation of ± 0.085. Data was normally distributed, with a coefficient of variation was 14.21 for the distance between AOM and GAN, and 22.00 for the distance between AOM and mastoid process. Therefore, GAN was reliably found bisecting about halfway between AOM and mastoid process.

References:
Raikos A, English T, Yousif OK, Sandhu M, Stirling A. Topographic anatomy of the great auricular point: landmarks for its localization and classification. Surg Radiol Anat. 2017;39(5):535-540. doi:10.1007/s00276-016-1758-y
Lefkowitz T, Hazani R, Chowdhry S, Elston J, Yaremchuk MJ, Wilhelmi BJ. Anatomical landmarks to avoid injury to the great auricular nerve during rhytidectomy. Aesthet Surg J. 2013;33(1):19-23. doi:10.1177/1090820X12469625

Figure 1. GAN Dissection Borders

Table 1. Descriptive Statistics

Figure 2. Data Distribution