A failsafe method to avoid injury to the great auricular nerve

摘要

Background: The great auricular nerve (GAN) is the most commonly injured nerve during facelift surgery. Although rare, injury can result in long-term sequelae. Objectives: Previous reports have described the nerve's location at the midbelly of the sternocleidomastoid muscle (SCM) or at its emergence from underneath the SCM. The purpose of our study was to identify the superior course of the great auricular nerve as it applies to facelift. Methods: Thirteen fresh cadavers were dissected. A vertical line through the midlobule was drawn perpendicular to the Frankfort's horizontal, acting as a reference to the course of the GAN. Transparent paper overlay tracings were then done to record each nerve's location. The distance from the bony external auditory canal (EAC) to the nerve was measured at the anterior muscle border, at the midbelly of the SCM, and as the nerve emerged from under the SCM. Branching patterns of the nerve and its relation to the external jugular vein were identified. Results: In 100% of the dissections, the superior course of the GAN fell within a 30-degree angle constructed using the vertical limb perpendicular to the Frankfurt horizontal and a second limb drawn posteriorly from the midlobule. The distance from the EAC to the nerve was 4.9 ± 1.1 cm at the anterior muscle border, 7.3 ± 1.0 cm at the midbelly of the SCM, and 9.8 ± 1.2 cm at the GAN's emergence from under the SCM. Four types of branching patterns were identified. Conclusions: The 30-degree angle described above rapidly and accurately identifies the nerve's location.