A patient with an upper tooth infection was referred to an ophthalmologist who cleared the eye. What spread pathway has the WORST prognosis?

Cavernous sinus thrombosis from odontogenic infections of maxillary posterior teeth is life-threatening with high mortality. Infection travels via the pterygoid plexus to the cavernous sinus. Ludwig's angina is also serious but more predictable to manage. Orbital cellulitis was ruled out. Cavernous sinus thrombosis = worst prognosis.