Introduction: Damage to the facial nerve (CNVII) is one of the most feared complications while performing parotidectomy. Despite preservation techniques, the rate of transient CNVII dysfunction with parotidectomy is up to 65% while that of permanent CNVII weakness has been reported to be 4-7%. Early identification of the CNVII using anatomical landmarks is critical in preventing iatrogenic injury to it during parotid surgery. The objective of this cadaveric surgical simulation study was to examine the relationship of the posterior auricular artery (PAA) with the main trunk of the CNVII, and to assess the utility of the PAA as an anatomic landmark for early identification of the CNVII during parotidectomy
Methods: A standard cervico-mastoid-facial incision was performed in 5 cadaveric heads bilaterally. The PAA was exposed on the surface of the mastoid process and the relationship of the PAA and CNVII was studied and recorded. Measurements of the diameter of the PAA at the point where it crossed the CNVII, the distance from the mastoid tip to the PAA (DT-MT-PAA), the distance from the external meatal cartilage to the PAA (DT-EMC-PAA) and the distance from the crossing point of PAA and CNVII to the surface of the mastoid process (DT-SMP-PAA) were recorded
Results: In all specimens, the CNVII trunk crossed the PAA inferior to the stylomastoid foramen and could be identified by tracing the PAA proximally. The average DT-EMC-PAA was 5.2(SD=0.2)mm and the average DM-PAA was 1.8(SD=0.2)mm. The mean DT-MT-PAA was 12.9(SD=2.3)mm, while DT-EMC-PF) was 5.2(SD=0.2)mm and DT-SMP-PF was 15.2 (SD=2.7)mm
Conclusions: Using the anatomic relationsip between PAA and CNVII, the CNVII trunk can be identified by simply following the PAA towards the stylomastoid foramen. Thus, PAA can be used as a novel anatomical landmark for identification of CNVII during parotidectomies, leading to lesser chances of inadvertent iatrogenic injury and risk of CNVII palsy
Patient Care: The use of posterior auricular artery as an anatomic landmark to locate the facial nerve will aid in early identification of facial nerve during parotid surgery, leading to lesser chances of inadvertent iatrogenic injury to it, thus leading to better clinical outcomes
Learning Objectives: 1. To understand the anatomic relationship between the facial nerve and the posterior auricular artery
2. To discuss the potential use of posterior auricular artery as a landmark for early identification of facial nerve during parotid surgery