Anatomic Landmarks for Localization of the Vertical Segment of Facial Nerve on Multislice CT Multiplanar Reconstruction Images.

The facial nerve decompression via mastoid is simple and easy to expose the vertical segment of the facial nerve (VFN). The objective of this study was to find out the relationship between the VFN and anatomic landmarks to facilitate prediction of the location of VFN during facial nerve decompression. The different landmarks were cochlear window (CW), oval window (OW), promontorium tympani (PT), and mastoid antrum (MA). Parameters of 140 patients (280 observations) with healthy middle ears were measured on high-resolution spiral multislice computed tomographic multiplanar reconstruction (MPR) images that were parallel to the base plane. The data gained were analyzed by statistical method and were also analyzed with respect to side and gender. The angle between orientation of VFN to the CW of the longest distance and horizontal axis was larger on the left side than that of the right (P < 0.05). Our results may provide more detailed information to predict the location of VFN during facial nerve decompression through mastoid.