Traumatic transection of the optic chiasm: magnetic resonance evaluation

Transcranial approach for treatment for traumatic optic chiasm syndrome

To describe the visual outcome of patients with a traumatic optic chiasm syndrome, with and without neurosurgical intervention. The retrospective clinical interventional study included 14 patients, who either underwent a neurosurgical intervention with transcranial decompression of the optic canal (11 patients) in combination with a high-dosage systemic corticosteroid therapy or who received a high-dosage systemic corticosteroid treatment only (3 patients). In the surgical group, visual field improved after surgery in 6 (55%) patients and remained unchanged in 5 (45%) patients, while in none of the patients without surgery, the visual field improved. Neurosurgical decompression of the optic chiasm and optic nerve canal may be associated with a visual improvement in some patients with a traumatic optic chiasm syndrome.

Traumatic chiasmal syndrome: a series of 19 patients

PURPOSE

To present a clinical series of 19 patients with traumatic chiasmal syndrome.

METHODS

A retrospective study was performed. This included all patients with traumatic chiasmal syndrome seen in the neuro-ophthalmology clinic at the Royal Adelaide Hospital between January 1970 and January 2000.

RESULTS

Of the 19 study patients, most were young males involved in motor accidents. Two-thirds had skull fractures. Three-quarters of patients had a final visual acuity of 6/12 or better in at least one eye. Ten patients had a complete optic nerve palsy. The incidence of diabetes insipidus in this study was 37%. The incidence of cranial nerve lesions, hypopituitarism, carotid cavernous fistula, and other deficits were documented. Magnetic resonance imaging and surgical findings were consistent with known mechanisms of chiasmal injury.

CONCLUSIONS

Trauma is a rare cause of chiasmal syndrome. Patients with bitemporal field defects should be questioned about prior head injury. In the acute setting, magnetic resonance imaging is the most useful investigation. The treating practitioner should anticipate and treat associated endocrine, ocular motility, and other disorders. Mechanisms of damage to the optic chiasm after trauma include direct tearing, contusion haemorrhage and contusion necrosis. These mechanisms should not be considered mutually exclusive. Unilateral temporal hemianopia with a fellow blind eye is not necessarily the result of chiasmal disruption.