Facial Nerve Injury in Temporomandibular Joint Approaches

Facial paralysis can be a devastating consequence resulting from blunt and penetrating trauma to the head and neck, as well as surgical injury, either accidental or due to involvement by tumor. In addition, the etiology can be attributed to a variety of other causes, ranging from infectious to metabolic, and is frequently idiopathic in nature. The incidence of facial nerve injury during temporomandibular joint (TMJ) surgeries varies among surgeons. There are many factors that could contribute to the injury of the temporal and zygomatic branches of the facial nerve. These nerves lie in a confluence of superficial fascia, temporalis fascia, and periosteum and may be injured by any dissection technique that attempts to violate the integrity of these regions. Excessive or heavy-handed retraction causes compression and/or stretching of nerve fibers resulting in neuropraxia. The facial nerve then enters the parotid gland, where the main trunk branches into the upper and lower divisions at the pes anserinus. The nerve further divides into five main branches: the temporal, zygomatic, buccal, marginal mandibular, and cervical. The temporal branch lies within the superficial muscular aponeurotic system at the level of the zygomatic arch. In this paper, we evaluate the facial nerve function based on the House-Brackmann grading index after the preauricular approach for the treatment of condylar fractures, pathologies, and TMJ ankylosis cases. The nerve functional regeneration postfacial nerve injury has been evaluated and reported in this retrospective study.