Size of renal calculi, recurrence rate and follow-up

Stones smaller than 5 mm in diameter seldom need any operation other than the use of the stone-basket. Stones larger than 10 mm in diameter usually need an operation, are more often accompanied by infection, and have a higher recurrence rate. The size of the stone is unrelated to the level of urinary calcium or to body surface area. In planning the follow-up of patients with calculi the size of the first stone is a useful guide.