Visualization of facial nerve in the parotid gland using sonography: A preliminary observation
Journal
Journal of Medical Ultrasound
Journal Volume
6
Journal Issue
4
Pages
165-168
Date Issued
1998
Author(s)
Abstract
Background: Imaging of the surgically significant intraparotid facial nerve has been the aspiration of many radiologists and head and neck surgeons. Ultrasonography has long been considered incapable of demonstrating the facial nerve, possibly because of the similarity of echogenicity or the attenuation of the ultrasonic beam by parotid parenchyma. In this study, we demonstrate the possibility of visualizing the facial nerve trunk through a window provided by a hypoechoic overlying tumor. Materials and Methods: Twelve patients with an infra-auricular mass scheduled for superficial parotidectomy were examined with a 5-10-MHz, broad-band, linear-array sonographic transducer. The main trunk of the facial nerve behind the shadow of the superficial tumor was carefully inspected with the probe held along the parasagittal plane of the head and insonating obliquely behind the ramus of the mandible. The finding was justified using power Doppler sonography to role out the possibility a vascular shadow and with air-sialography to role out an excretory duct. Results: Sonographic shadows of the cross section of a tubular structure were demonstrated in nine cases with superficially located tumors. Surgical correlation indicated identical locations of these sonographic shadows and the facial nerve tract. No vascular signal was detected inside these tubular shadows with power Doppler sonography, and no change of echogenicity was found after filling of the excretory duct system with air in a test case. Conclusion: Utilizing the hypoechoic 'through transmission window' of some hypoechoic superficial tumors, we could clearly define the relationship between the facial nerve trunk and the tumor.
Subjects
Facial nerve; Parotid tumor; Sonography
SDGs
Other Subjects
article; cancer surgery; clinical article; Doppler echography; facial nerve; human; observation; parotid gland tumor; preoperative evaluation
Publisher
Elsevier (Singapore) Pte Ltd
Type
journal article