Bilateral traumatic abducens nerve avulsion: A case series and literature review.

Although abducens nerve palsy is an established sequela of head trauma - given the prolonged intracranial course of the nerve - bilateral injury is rare. Here, we present two cases of bilateral traumatic abducens nerve avulsion, in the absence of regional fractures, one of which presented two months following the initial trauma. Additionally, we review the current literature on bilateral abducens nerve palsy secondary to trauma, discussing the anatomy of the nerve's course and potential mechanisms of injury.

Delayed-onset bilateral abducens paresis after head trauma.

Bilateral sixth nerve paresis following closed head injury, though rare, is a known entity. However, delayed-onset post-traumatic bilateral abducens paresis is extremely rare. We present two cases. The first patient had onset of bilateral abducens paresis 2 weeks after closed head injury and the second patient after 3 days. The cause in the former was detected to be chronic subdural hematoma and in the latter is speculated to be edema/ischemia due to injury to soft tissue structures housing these nerves. The delayed onset of bilateral abducens paresis following head injury may vary according to the cause. There may be another mechanism of injury apart from direct trauma. Though rare, it needs to be evaluated and may have a treatable cause like elevated intracranial pressure.

Bilateral traumatic facial paralysis associated with unilateral abducens palsy: a case report.

Bilateral traumatic facial paralysis is a very rare clinical condition. Abducens palsy, associated with bilateral traumatic paralysis, is even rarer and has not been well described in the literature. In this report, a 24-year-old male, who developed immediate bilateral facial and right abducens paralyses following a motor vehicle accident, is presented. The patient was referred for neurotologic evaluation 22 days after the injury. Electroneurography (ENoG) demonstrated 100 per cent degeneration at the first examination and, correspondingly, electromyography showed no regeneration potentials. Using high-resolution computed tomography (HRCT), a longitudinal fracture on the right and a mixed-type fracture on the left were identified. The patient had good cochlear reserve on both sides. The decision for surgery was based not on ENoG, because of the delayed referral of the patient, but on the HRCT, which showed clear fracture lines on both sides. The middle cranial fossa approach for decompression of the right facial nerve was performed on the 55th day following the trauma, and a combined procedure using the middle cranial fossa and transmastoid approaches was applied for decompression of the left facial nerve on the 75th day following the trauma. On the right, there was dense fibrosis surrounding the geniculate ganglion and the proximal tympanic segment whereas, on the left, bone fragments impinging on the geniculate ganglion, dense fibrosis surrounding the geniculate ganglion, and a less extensive fibrotic tissue surrounding the pyramidal segment were encountered. There were no complications or hearing deterioration. At the one-year follow up, the patient had House-Brackmann (HB) grade 1 recovery on the right, and HB grade 2 recovery on the left side, and the abducens palsy regressed spontaneously. The middle cranial fossa approach and its combinations can be performed safely in bilateral temporal bone fractures as labyrinthine sparing procedures if done on separate occasions.