Management of the facial nerve following temporal bone ballistic injury

• Published in: Laryngoscope investigative otolaryngology 2022-10, Vol.7 (5), p.1541-1548
• Main Authors: Maxwell, Anne K., Lemoine, John C., Kahane, Jacob B., Gary, Celeste C.
• Format: Article
• Language: English
• Subjects: ballistic injury; Carotid arteries; Demographics; Energy; facial nerve; Firearms; Fractures; gunshot wound; Hearing loss; Hispanic people; Injuries; Meningitis; Original Research; Otology, Neurotology, and Neuroscience; Patients; Steroids; Surgery; temporal bone; temporal bone fracture; Trauma; Velocity
• ISSN: 2378-8038; 2378-8038
• DOI: 10.1002/lio2.880

Objective To understand the patterns of temporal bone fracture and facial nerve injury from ballistic trauma. Study Design Retrospective case series. Methods Retrospective review of 42 patients evaluated following temporal bone ballistic injury at a single institution, university‐based level‐one trauma center between 2012 and 2021. Demographics, facial nerve status, CT images, interventions, complications, and outcomes were reviewed. Results Mean age 30.3 years (range 5–58 years); 79% male. Racial demographics reflected the surrounding community. Seven mortalities occurred. Nineteen patients (54%) demonstrated facial nerve injury. Of those, 13/19 displayed immediate paralysis, 1 delayed, 5 unknown (due to altered mental status). On consultation, House‐Brackmann grade 6 paralysis was common (13/19). Fracture was otic capsule‐sparing in 17/19 (90%), universally comminuted, with significant disruption along the mastoid tip (16/19), external auditory canal (EAC) (15/19), and periauricular soft tissues (13/19). Nine patients underwent surgical intervention: Transmastoid facial nerve decompression to remove compressive bony spicules (n = 5); eye protection surgery (n = 3); and peripheral facial nerve exploration (n = 1), noting transection at the pes. One required middle cranial fossa and transmastoid repair of cerebrospinal fistulae in setting of severe meningitis. House‐Brackmann scores improved in 80% following transmastoid nerve decompression despite CT evidence of likely additional injury in its extratemporal course. Conclusions Common patterns of temporal bone fracture seen in blunt trauma (longitudinal/transverse, otic capsule‐sparing/disrupting) were not found in patients with ballistic facial nerve injury. Rather, injury was commonly apparent in the EAC, mastoid tip, and periauricular soft tissues. Clinicians should have high suspicion for extratemporal facial nerve injury following ballistic trauma. Ballistic injury to the temporal bone was commonly seen in the external auditory canal, mastoid tip, and periauricular soft tissues. There is a high risk of facial nerve injury, often in the mastoid segment near the stylomastoid foramen. Facial nerve decompression in the acute period, even in setting of extratemporal injury is likely to be beneficial.