Is a periodontal abscess that results in a fistula a situation that the tooth is 99% of the time extracted or root canaled (want to be prepared)?

Either: Either. Depends on the tooth. Dentist who examines you can tell you better.

Periodontal Abscess: If the problem is periodontal in nature (as you described) then root canal therapy is not indicated. If the problem is endodontic in nature, then root canal therapy would resolve the issue. Let your periodontist explain your problem rather than internet guessing.

Perio Abscess: A periodontal abscess is treated with definitive periodontal treatment which may include periodontal surgery along with antibiotics. A periapical absess is treated with Root Canal Therapy but may also include periapical surgery. Occasionally we have a perio-endo abscess that requires multiple methods of treatment. Your own dentist can determine what needs to be done, prognosis & treatment options.

It depends: It depends on whether the tooth is loose indicating bone loss. If the bone loss is minimal and the tooth is not loose it can often be saved. Root canal is rarely indicated for periodontal disease.

Not necessary: Treating fistula perio-dental abscesses may involve root canal treatments or in more severe cases be followed with periodontal surgery. Fistula drainage in dental abscesses tend to heal naturally when the cause has been removed.