Certain types of kidney stones can be dissolved. Uric acid and cystine stones can be dissolved in some patients, although this does not always work and surgery may be required.
Generally kidney stones are (very painfully unfortunately) passed 'naturally' - and if your doctor diagnoses you with kidney stones, he will probably give you painkillers and tell you to drink plenty of fluids.
Sometimes surgery is required if the stones are too large to pass or if they are stuck. A stent may be placed inside the urethra either following surgery to help healing and prevent swelling; or as a way to help pass the stone.
A stent is a soft, hollow, plastic tube which sometimes has a string attached which will remain outside the body for easy removal. Stents are not left in for more than 3 months as stones can form on them which obviously makes removal difficult.
Men are more likely to get kidney stones than women and they can be hereditary. Some very unfortunate people suffer with these on a regular basis, though drinking plenty of fluids regularly will go some way towards preventing the formation of kidney stones initially.