Even with the "fall" of the Western half of the empire, I'd argue that, in a way, it still survived even after 395. The kingdoms of the Vandals, Visigoths, Ostrogoths, Alans, and Franks all, largely, followed Roman Christianity, wrote Roman-style legal documents, and the ruling class of those "barbarian" kingdoms adopted Latin as a court language. Ethnically, the Western Roman armies had already Germanized heavily before 395, so replacing overall rule with the new "barbarians" probably wouldn't have been noticed much by the common people, if at all. Honestly, if we define "Roman civilization" as its laws, customs, and religions, then I'd argue that Justinian did more damage to Roman civilization than he "saved" by invading them from 533 to 554.
Even with the "fall" of the Western half of the empire, I'd argue that, in a way, it still survived even after 395. The kingdoms of the Vandals, Visigoths, Ostrogoths, Alans, and Franks all, largely, followed Roman Christianity, wrote Roman-style legal documents, and the ruling class of those "barbarian" kingdoms adopted Latin as a court language. Ethnically, the Western Roman armies had already Germanized heavily before 395, so replacing overall rule with the new "barbarians" probably wouldn't have been noticed much by the common people, if at all. Honestly, if we define "Roman civilization" as its laws, customs, and religions, then I'd argue that Justinian did more damage to Roman civilization than he "saved" by invading them from 533 to 554.