Temporal Bone Fractures Caused by Ballistic Projectiles: A Systematic Review

Gun shot injuries to the temporal bone: Anatomic predictors of mortality

PURPOSE

To explore anatomic predictors of mortality from gunshot wounds involving the temporal bone.

METHODS

A retrospective search of radiology reports was performed for all patients with CT reports suggestive of gunshot wounds (GSW) to the TB (2000-2020). All cases were reviewed by the senior author to confirm injury to the temporal bone. Detailed demographic and radiographic data were collected.

MAIN FINDINGS

A total of 120 patients met inclusion criteria. The majority of patients were male (n = 101) and the average age was 32.9. The squamosa was the most commonly involved subsite (n = 90), followed by the mastoid (n = 43). Squamosal entry site had the highest associated mortality (89.7 %). For those with known disposition, 65.8 % (79 of 120) expired on the same hospital admission. Inpatient otolaryngology consultation was noted in 18.3 % (n = 22) of patients, with poor outpatient follow-up.

CONCLUSIONS

This series represents the largest survey of GSW to the temporal bone to date. Although associated mortality is high and outpatient follow-up poor, otolaryngologists should be aware of associated morbidities to facilitate both inpatient and subsequent outpatient management.

Audiologic Consequences of Gunshot Wounds to the Temporal Bone Show No Relation to Concomitant Neurologic or Vascular Injuries

OBJECTIVES

To evaluate audiologic consequences of gunshot wounds (GSWs) to the temporal bone (TB), and to correlate hearing outcomes with neurologic and vascular injuries adjacent to the temporal bone.

STUDY DESIGN

Retrospective case series.

SETTING

University-based level-one trauma center.

METHODS

Retrospective review of 35 patients surviving TB ballistic injury, 2012 to 2021. Main outcomes were audiologic results. Demographics, concomitant injuries, CT, and interventions were reviewed.

RESULTS

Mean age was 30.7 years; 80% male. Seventeen patients (48.6%) underwent audiologic testing. Mean pure tone average (PTA) was 75 ± 35 dB, bone line average 41 ± 26 dB, and speech discrimination score (SDS) 60 ± 43%. Nineteen (54.3%) demonstrated facial nerve injury (FNI), who were more likely to show SNHL especially anacusis, though their mean PTA and SDS were not statistically different from those without (P = .30 and .47, respectively). Radiographic review of those with sensorineural loss (SNHL, 6/17) revealed otic capsule-disrupting fracture (n = 2), pneumolabyrinth (n = 2), intracranial hemorrhage (n = 3). Those with mixed loss (6/17) showed otic capsule-sparing fracture (n = 6), EAC injury (n = 5), ossicular discontinuity (n = 2), and intracranial hemorrhage (n = 4). Two with mastoid tip fractures alone had normal audiograms. Audiometric outcomes were not predicted by concomitant CSF leak, spinal injuries, vascular injuries, cranial neuropathies, or traumatic brain injury.

CONCLUSIONS

All patterns of hearing loss-conductive, sensorineural, mixed and normal-may be seen following TB ballistic injuries. Trauma severe enough to disrupt the facial nerve is more likely to cause anacusis. However, all should be formally evaluated, since ballistic injuries complicated by neurologic or vascular damage do not necessarily correlate with worse audiologic outcomes, while patients with minimal fractures may demonstrate losses.

Bulletproof Temporal Bone: A Case of Self-Inflicted Ballistic Injury

Temporal bone injuries due to gunshot wounds are uncommon but devastating, with a high risk of damage to critical neurovascular structures. The high resistance of the temporal bone, the densest bone in the human body, can sometimes avoid a fatal outcome. However, the complications are in many cases devastating and include hearing loss, facial paralysis, cerebrospinal fluid leakage, intracranial damage, and vascular injuries. Our goal was to report a case of ballistic injury to the temporal bone and describe the surgical approach taken for treatment. A 74-year-old man was transferred to the emergency room of our tertiary hospital, intubated and sedated, after an attempted suicide with a firearm. The CT scan showed the metal projectile lodged within the temporal bone on the right side, with the destruction of the ossicular chain and bony labyrinth. After stabilization, sedation was reversed, and the otolaryngology team was called. On examination, the entry wound was located in the cavum concha, with no active bleeding but presenting active otorrhea of cerebrospinal fluid. The patient had complete peripheral facial paralysis on the right side and spontaneous horizontal nystagmus toward the left side. Empirical antibiotic therapy was initiated. A subtotal petrosectomy was performed, with the removal of the foreign body, repair of the cerebrospinal fluid fistula, obliteration of the cavity with abdominal fat, and closure of the external auditory canal. He was discharged on the 11th-day post-surgery, maintaining complete facial paralysis and right-side anacusis, but was able to walk with assistance. In conclusion, penetrating trauma of the temporal bone is a potentially life-threatening situation, and patients that survive have a guarded prognosis, as it often leads to permanent sequelae even when managed promptly.

Evidence-Based Medicine for Ballistic Maxillofacial Trauma

Ballistic trauma is a serious health issue with significant costs to physical, psychosocial, economic, and societal well-being. It may be caused from firearms, explosive devices, or any other projectile forces, and is characterized by severe tissue loss and evolving tissue devitalization. This review covers mechanism, diagnosis, and management of ballistic maxillofacial trauma, specifically. Initial evaluation includes stabilization of airway, bleeding, and circulation, followed by assessment of other injuries. The overall degree of tissue damage is determined by intrinsic patient factors and extrinsic projectile factors. Management of ballistic injuries has shifted toward advocation for early operative repair with the advent of antibiotics and advanced techniques in maxillofacial reconstruction. Appropriate timing and method of reconstruction should be carefully selected on a case-by-case basis. While ballistic trauma research is limited to studies biased by institutional practices, areas for further study identified from current literature include guidelines directing timing of reconstructive surgery; thresholds for free tissue transfer; handling of retained projectiles; incidence of surgical complications; and clinical outcomes for computer-aided surgical repair of these highly destructive injuries.

Vascular injury arising from lateral skull base fractures

PURPOSE

Although uncommon, vascular injury can be seen in patients with lateral skull base fractures (LSBF). However, little is known about this potentially life-threatening comorbidity. The objective of this study is to better characterize the vascular injuries associated with temporal and lateral sphenoid bone fractures.

BASIC PROCEDURES

Retrospective review of all patients with computed tomography angiography (CTA) performed specifically to evaluate for vascular injury following LSBF. In addition to patient demographics (age, gender, race), the mechanism of injury, the location of fracture(s), and the nature of vascular injury diagnosed by CTA was recorded. Two-way ANOVA was performed to determine if any variables were predictive of vascular injury.

MAIN FINDINGS

From 2011 to 2021, 143 patients with 333 subsite fractures met inclusion criteria. Of all patients, 46 (32.2 %) had CTA evidence of at least one vascular injury, the most common type being venous thrombosis/filling defect (41.7 %). Evidence of vascular injury was unclear in 14 patients (9.8 %). Fractures most associated with vascular injury ranged from 0.7 % (otic capsule fractures) to 26.7 % (mastoid, lateral sphenoid fractures). Risk of vascular injury was no different between patients with single vs multiple fractures. There were no fracture locations that could reliably predict specific vascular injury.

CONCLUSIONS

Over 40 % of all CTAs ordered following LSBF identified were suspicious for associated vascular injury. Yet fracture location and number cannot reliably predict vascular injury. Until such determinants can be better identified, clinicians should have a low threshold to obtain CTA to rule out associated vascular injury.

Management of the facial nerve following temporal bone ballistic injury

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.