Kidney Stones 101

by Andrew C. McGregor, MD | Lexington Clinic Urologist

Nephrolithiasis, or kidney stones, are a common reason for patients to seek care from a urologist. Kidney stones typically form in the kidney where then can remain completely asymptomatic for many years. The pain usually associated with kidney stones occurs when the stone tries to pass from the kidney, down the ureter and into the bladder. This pain is often severe and can occur in the back, side or abdomen. Frequency and urgency of urination can occur when the stone is near the bladder. Kidney stones can also lead to blood in the urine.

The most common variety of kidney stone in this region is composed of calcium and oxalate. Both of these components are present in many foods that make up our diet. High oxalate foods include tea, chocolate, nuts, spinach and rhubarb. Other common types of kidney stones include stones composed of uric acid and stones related to urinary tract infections, called struvite stones.

Treatments for kidney stones depend on the size, composition and location of the stone. Kidney stones composed of uric acid can be dissolved by altering the acidity of the urine. Some kidney stones require surgical treatment if they do not pass. Surgical options include:

  • extracorporeal shock wave lithotripsy (ESWL)
    This procedure utilizes sound waves from outside the body to fragment the stone. This is best suited for stones within the kidney or upper part of the ureter.
  • ureteroscopy
    This procedure involves using a small telescope to go up the ureter to the stone and either remove it with a basket or fragment it into small pieces with a laser.
  • percutaneous nephrolithotomy (PCNL)
    This is the most invasive of the three methods and requires a small incision in the back, through the kidney to access the stone. This procedure is reserved for large kidney stones within the kidney.


Prevention is the key to minimizing the risk of forming or passing a kidney stone. In more than 50 percent of first time stone formers, additional stones can be prevented by aggressive hydration. Urine output should be at least 2 - 2.5 liters per day. Lemonade or lemon juice can also be helpful in preventing stone formation. Diets low in salt and oxalate can aid in minimizing stone risk. Some patients, however, have metabolic abnormalities which predispose them to stone formation; an evaluation of the urine and blood by a urologist can often identify these abnormalities and lead to preventive therapy.

For more information about kidney stones or to schedule an appointment, call 859.258.4DOC (4362).