What kind of surgery do they do on a 7mm kidney stone?

Lithotripsy....: Nowsdays, laser lithotripsy through a fine long flexible telescope can do a lot of wonder of stone removal; it's safe and patient tolerates well, but at times, a stent for 5-10 days may be required to ease ureteral healing after lithotripsy. For detail, ask urologist. Besides, practicing stone prevention is essential part of care as advised by your urologist. Best wish...

Lithotripsy : Depends on your symptoms and location of the stone. If it's causing pain , obstruction or pressure on the kidney it can be crushed by ultrasound waves. Sometimes they may need to put a temporary stent in the ureter to help the crushed pieces come down uneventfully, that is without much pain or complications. Once the stone pieces are out the stent is taken out. It's an easy procedure in good hands.