ESWL can be considered if:

The stone is not passing on its own and is causing pain that will not go away.

The stone is completely blocking the urine flow.

You have only one working kidney, and your doctor worries that the stone is affecting that kidney's ability to function.

The stone is causing serious bleeding.

The stone continues to grow.

You have had a kidney transplant, and your doctor worries about damage from a stone.