Can sinus infection as the result of bad wisdom tooth infection bone/fracutre cause spine infection? is there barrier between spinal fluid and sinus?

No: Bad sinus disease if left untreated can cause intracranial infection or even brain abcess. The infection erodes through the bone and covering of the brain. This can cause meningitis, but not necessarily spine infection.

No direct connection: There is not direct connection between sinuses and spinal fluid. They are proximal to one another but separate. An infection from teeth can get into the sinus. Most infections travel thru the blood. Though there are brain abcesses that started as a tooth infection, these are rare. See your md if you are experiencing symptoms of any infection.