Basilar skull fracture: a risk factor for transverse/sigmoid venous sinus obstruction

In trauma practice, basilar skull fracture is an extremely common finding while transverse/sigmoid venous sinus thrombosis is generally considered quite a rare complication. During evaluation of cervical computed tomography (CT) angiography after trauma, we identified five patients in just three months with unexpected transverse/sigmoid venous sinus obstruction ipsilateral to a basilar skull fracture. This number represented a surprisingly high percentage of our neurosurgical trauma consults for the study period (31%). Three of the five patients were found to have sinus thrombosis: two with right transverse/sigmoid sinus thrombosis experienced significant neurological deficits and prolonged hospital courses even with anti-coagulation therapy; one patient with a left transverse/sigmoid sinus thrombosis had a good outcome with anti-coagulation therapy. The other two of the five patients had outflow obstruction, likely from focal epidural bleeding and extrinsic compression: one patient with partial obstruction in the right transverse-sigmoid junction, due to epidural bleeding, experienced a difficult recovery; one patient with a right sigmoid sinus obstruction presented and remained asymptomatic and experienced a benign hospital course. Two of the five patients had a posterior temporal hemorrhagic area ipsilateral to the affected sinus, suggesting that this finding may have represented hemorrhagic venous infarction rather than traumatic contusion. We propose that a basilar skull fracture in the region of temporal or occipital bone should be considered as a significant risk factor for the development of transverse/sigmoid venous sinus obstruction and may be an under-recognized and treatable cause of increased intracranial pressure. Failure to detect this complication may explain, in part, unexpected clinical outcomes.