Bifid Facial Nerve Trunk: Anatomic and Surgical Considerations.

The segment of the facial nerve (FN) between its emergence from the skull through the stylomastoid foramen and its bifurcation at the parotid area is referred to as the FN trunk (FNT). Injury to the facial nerve trunk is among the most undesirable outcomes following different otologic, plastic, maxillofacial, and neurosurgical procedures. These procedures frequently involve manipulation and isolation of this segment, and meticulous dissection should be practiced to avoid iatrogenic damage to the nerve. Identification and exposure of the FN trunk, however, may be difficult because it is surrounded by dense connective tissue. This dissection becomes even more difficult and risky when the normal anatomy is distorted.During a routine left conservative superficial parotidectomy of a Pleomorphic Adenoma in the superficial lobe of the left parotid gland, duplication of the FNT was encountered. The FNT after its exit through the stylomastoid foramen, split into 2 main divisions, which rejoined before its penetration into the parotid gland. To the best of our knowledge, this variation has not been previously reported.