The wrist or forearm fistula is the first choice of fistulas where it is possible. It gives the longest length fistula, is the most convenient to use, and requires the least amount of surgery. This fistula keeps all the other options open. Even if the fistula never becomes usable, it will start building up the veins in that arm, making a fistula in the upper arm easier. Unfortunately, this fistula is not always possible: the veins may have been ruined by intravenous catheters, or the vessels may just be too small.