Comment by latk

That's not an issue if only the ID is used to identify the submission, whereas the title slug is only human-readable fluff. E.g

    /item/1234/original-submission
    /item/1234/edited-title
    /item/1234/arbitrary-string
    /item/1234/

This could also be done with the current query string approach, e.g.

    /item?id=1234&title=original-submission
    /item?id=1234&title=edited-title
    /item?id=1234&title=arbitrary-string
    /item?id=1234

OP's suggestion of having the title be part of the ID would be quite inelegant, but possible if the real ID is only the digits up to the first hyphen.

Ideally, the title would be completely ignored, but other titles would redirect to an URL with the current title.