(HealthDayNews) -- If you've had a kidney stone, you know how painful it can be. Most kidney stones pass from the body without medical help. But sometimes a stone will not just go away. It may even get larger.
A kidney stone is a solid piece of material that forms in the kidney from substances in the urine. It can stay in the kidney or break loose and travel down the urinary tract, according to the National Institute of Diabetes and Digestive and Kidney Diseases.
If you have a stone that will not pass by itself, your doctor may need to help you get rid of it. In the past, the only way to remove problem stones was through surgery. Now, doctors have new ways to remove them, including shock waves that break a large stone into smaller pieces that will pass through your urinary system.
Another option is tunnel surgery, in which the doctor makes a small cut into the patient's back and makes a narrow tunnel through the skin to the stone inside the kidney. With a special instrument that goes through the tunnel, the doctor can find the stone and remove it.
