Analyzing the facial nerve at Zuker's point using geometric morphometrics: a cadaveric study.

Abstract

Background: Surface landmarks such as Zuker's point can help localize branches of the facial nerve as a supplement to, or in the absence of intraoperative neuromonitoring. Zuker's point is a previously described landmark located half the distance between the root of the auricular helix and labial commissure with demonstrated efficacy in localizing facial nerve branches. However, prior studies are restricted by two dimensional descriptions based on discrete, linear measurements, and description of the influence of sex, laterality, or face shape is lacking. Geometric morphometric techniques offer a sophisticated approach capable of producing a three-dimensional description of the location of the facial nerve relative to Zuker's point, while discerning the influence of sex, laterality, and face shape.

Methods: Facial nerve at Zuker's point was analyzed in 82 cadaveric hemifaces. Three-dimensional coordinate data for the root of the auricular helix, labial commissure, Zuker's point, and the facial nerve at Zuker's point were captured using a MicroScribe digitizer. Mean landmark configuration and principal component analysis were used to describe the position of the facial nerve relative to Zuker's point, as well as the influence of sex, laterality, and face shape.

Results: Facial nerve systematically deviated towards the 1 o'clock position (if viewed from the lateral position on the right side), irrespective of sex or laterality. The accuracy of Zuker's point was enhanced on those with a longer, rounder face, while in shorter and slimmer faces the nerve takes a more superior and superficial position relative to Zuker's point.

Conclusions: Facial nerve branches can reliably be found at Zuker's point, regardless of sex or laterality, though the nerve does systematically deviate from Zuker's point toward the 1 o'clock position (if viewed on the right side). The position of the facial nerve relative to Zuker's point is influenced by face shape, but not sex or laterality. These results can be used to better localize the facial nerve and improve patient outcomes.