Anatomical Feasibility Study of the Digastric Branch of the Facial Nerve: A Potential Donor for Facial Nerve Reanimation

Abstract

The digastric branch is the second branch of the facial nerve after emerging from the stylomastoid foramen. To the best of our knowledge, few detailed anatomic studies of the digastric branch have been performed. Moreover, the use of the digastric branch for facial nerve reanimation has not been explored. Nine sides of 5 fresh frozen cadavers were dissected for anatomic observation ofthe digastric branch and exploration of the feasibility of the digastric branch as a donor for facial nerve reanimation. The facial nerve trunk (FNT) and digastric branch were readily found by dissection using the tragal cartilage and tragal pointer as landmarks. The length and diameter of the digastric branch were measured, and the digastric branch was repositioned anterior to the FNT and the 2 major extracranial divisions of the FNT. On all sides, the digastric branch existed as a single branch and innervated only the posterior belly of the digastric muscle. The available length of the digastric branch was 13.28±2.47mm (range, 8.87 to 16.38mm), and the mean diameter was 0.98±0.31mm (range, 0.64 to 1.64mm). The digastric branch reached the FNT and its 2 major divisions without tension. The results of the present study have clarified the anatomic findings of the digastric branch in detail and the feasibility of using the digastric branch as a potential donor for facial nerve reanimation. The surgeon might consider the use of the digastric branch as a feasible donor for facial nerve reanimation based on the findings from our cadaveric study.