[Bitemporal hemianopsia after skull base fracture]

We report a case of bitemporal hemianopsia after skullbase fracture. An 18-year-old male presented with frontal head hit due to a traffic accident. Consciousness level on admission was JCS 10. Initial CT scan revealed traumatic SAH and pneumocephalus. We treated him conservatively. Ten hours after the accident, consciousness level went down, and CT imaging disclosed bilateral frontal hemorrhage. The three dimensional CT (3D-CT) imaging showed two fracture lines from the roof of the ethmoid sinus to the planum sphenoidale. Although his consciousness improved gradually, he complained of rhinorrhea, anosmia and double vision. On preoperative visual field examination, bitemporal hemianopsia was noticed. Repair operation for CSF rhinorrhea was performed. Operative findings revealed two fracture lines corresponding to the 3D-CT scan. The optic chiasm was compressed by the tuberculum sellae. We could not find obvious tearings or stretchings of the chiasm. Reports on operative findings of traumatic chiasmal syndrome are rare, and most of the reports presume that bitemporal hemianopsia results from tearing or stretching of the chiasm. We could confirm that, in some cases, bitemporal hemianopsia could result from direct pressure of the tuberculum sellae.