You will be given a definition of a task first, then some input of the task.
Given an abstract, generate a keyword (a noun phrase) that best describes the focus or contribution of the paper. Such keywords can be directly from the given abstract or outside it.

Abstract: A carotid-cavernous fistula recurred 16 years after a Hamby procedure. The recurrence was manifested by subarachnoid hemorrhage originating from dilated draining pial veins. The fistula was closed with a balloon catheter introduced through a patent remnant of the cervical carotid artery. Patients who have previously undergone Hamby trapping and embolization should be reassessed for an occult fistula that could predispose them to intracranial bleeding.
Output:
Adult