High-resolution ultrasound of the marginal mandibular branch of the facial nerve: Normal appearance and pathological findings in a postsurgical case series

Background The aim of this study was to validate high-resolution ultrasound (US) as an imaging modality able to map the normal marginal mandibular nerve (MMN) and recognize its abnormalities in the postoperative setting. Methods The ability of US to recognize the MMN was first tested by injecting latex under US guidance on three fresh frozen cadavers. Then, a standardized scanning protocol was established on 20 healthy volunteers based on appropriate landmarks. Finally, a postsurgical series of three patients with MMN abnormalities were examined with US. Results In the cadaveric study, US-guided latex injection provided identification of the MMN. In healthy volunteers, US was able to recognize the MMN for a segment of 3.4 +/- 1.2 cm in length. Pathologic abnormalities of the MMN were detected and characterized in three patients. Conclusions High-resolution US is a valuable diagnostic tool to identify the MMN and might have potential for detecting its pathologic changes.

Automated summary

This study validated the use of high-resolution ultrasound in mapping the normal marginal mandibular nerve (MMN) and identifying abnormalities postoperatively. The research showed that ultrasound could effectively recognize the MMN and detect pathological changes, as demonstrated in cadaveric studies, healthy volunteers, and patients with MMN abnormalities. High-resolution ultrasound has potential as a valuable diagnostic tool for identifying and monitoring MMN abnormalities.