Approximately 13% of men and 7% of women in the United States will have a kidney stone sometime in their lifetime. The prevalence of kidney stones is increasing significantly in the United States.
At the University of Michigan Health System, our Endourology, Kidney Stone and Lithotriptor Program has a history of outstanding clinical care, innovation and research.
As a comprehensive stone program we provide patient services across the entire spectrum of care – working closely with endocrinologists, nephrologists and radiologists to offer the best care possible to you. Our urologists are experts in diagnostic evaluation, surgical therapies, metabolic studies and nonsurgical care, and treat approximately 1000 stone patients a year. We intend to evaluate you and then manage your problem quickly, efficiently and effectively. We aim to minimize the duration of the period from symptom onset to resolution of the problem, and to resolve the problem with minimally-invasive techniques that are individualized for your specific situation.
Kidney Stone Signs and Symptoms
Urinary stones are crystals that form when dietary minerals in the urine become supersaturated. Stones almost always start in the kidneys. They may cause problems there, or may not be noticed until they move into the ureter (the tube that connects each kidney to the urinary bladder). Once stones pass down the ureter into the bladder, they usually then are passed with the urine, but sometimes they can lodge in the bladder and grow larger there.
The most common symptoms of kidney stones are pain in the flank or upper back. When the pain is severe there is often nausea as well. There can be blood in the urine and also possibly a urinary tract infection. Stones are diagnosed with CT scans, X-rays, or ultrasound, and can cause or can be a result of obstruction (blockage) of the kidney or ureter.
Kidney Stone Treatment Options
We work with patients in every stage of their condition – including creating a personalized surgical plan if surgery is needed. We also work with you to identify metabolic factors that may be causing the stones, so we can keep current stones from getting larger and reduce the risk of developing future stones.
When suspected of having a kidney stone, in addition to a history and physical, patients will be directed to undergo some type of radiological imaging study. These studies may include a plain x-ray of the abdomen, a renal ultrasound, or a CT scan (see images below). These studies are performed to determine the location of the stone, the size of the stone, the degree to which the stone may be causing an obstruction to the flow of urine from the kidney, and what types of therapy would be appropriate for management.
Kub (plain abdominal radiograph)
CT Scan showing left kidney stone
CT scan showing right ureteral stone
In acute cases, especially if the stone is small, you will often first receive conservative treatment to help facilitate stone passage. These treatments include pain management, hydration and medical expulsive therapy using drugs such as alpha blockers as described below. Many stones will pass with this management, without requiring a surgical procedure. A good rule of thumb is that the smaller the stone, the quicker it will pass. The following table is a guideline for patients with ureteral stones. This table shows the typical length of time for stone passage based on the size of the stone:
Stone size Time to passage Time to passage
2 mm 1 week
3 mm 2 weeks
4-6 mm 3 weeks
Medical therapy for stones include: 1) Drinking plenty of fluids (6-8 glasses/day). Water is the best, but juices or lemonade are acceptable. 2) Pain medications (acetaminophen- Tylenol ®, NSAID’s-eg. Advil®, Motrin®, for mild to moderate pain) (Narcotics-Vicodin ®, Norco®, etc. for severe pain). 3) Alpha-blockers such as Tamsulosin-eg. Flomax®. These medications have been shown to decrease the time needed to pass a stone and reduce the amount of pain during a stone attack.
Minimally Invasive Surgical Treatment
Factors that influence stone passage include the stone’s size and location. The larger a stone becomes the less chance it will pass without a surgery. The surgical procedures used today to remove stones are minimally invasive and highly successful. The most common techniques include shock wave lithotripsy (SWL), ureteroscopy and percutaneous methods. Our surgical team performs hundreds of these procedures every year, using the latest technical advances and equipment.
Extracorporeal Shockwave Lithotripsy for Small Urinary Stones: Shock wave lithotripsy is the least invasive procedure and is done on an outpatient basis. Using X-ray or ultrasound imaging to identify the stone, shockwaves are applied from outside the body to break the stone into smaller fragments which are then passed in the urine. This procedure works best on stones that are less than 2 centimeters in size (almost an inch) and located in the kidney.
Ureteroscopy with Laser Lithotripsy for Almost Any Urinary Stone: For stones in the ureter or the lower portion of the kidney ureteroscopy may be used. This minimally-invasive outpatient procedure involves placing a small diameter fiberoptic ureteroscope through the bladder and into the ureter, allowing the urologic surgeon to see the stone. They can then use surgical instruments to remove the stone, or a laser to break it into smaller pieces that can be passed in the urine. This technique is especially useful for frequently recurrent stones or stones that have been resistant to extracorporeal shockwave lithotripsy.
Percutaneous removal of Large Urinary Stones: Minimally-invasive percutaneous surgery is an option for the very largest and most complicated stones, those that are greater than 2 centimeters in size or when there are other complicating factors such as infection. This endoscopic procedure involves making a half-inch incision in the back through which the surgeon extracts stones using a nephroscope. Patients typically require a one to three night hospital stay, followed by a brief recovery period at home.
Medical Treatment to Prevent Stones
Factors which increase the risk of stones include:
- Gender: Men are more likely than women to form kidney stones, although the rate is increasing faster in women and soon men and women might have equal risk of kidney stone formation
- Family history: If you have family members with stones, you have a higher risk of developing kidney stones
- Diet: Diets high in fat, processed sugar, and salt place people at risk of forming kidney stones
- Weight: Obesity is strongly associated with kidney stones
- Personal history: If you formed your first stone when you are young, or if you have already formed more than one stone, you are at greater risk of having more stones
The cornerstone of medical treatment to prevent stones is increasing fluid intake. It is recommended that you drink enough fluid to produce 2 liters of urine each day. That is the equivalent to the amount of fluid in a 2 liter soda bottle. It’s important that you spread this out over the entire day rather than drinking the whole amount at one time. It is recommended that you include a glass of water just before bedtime. The goal is to make sure your urine has the appearance of water. If the urine is yellow then you probably aren’t drinking enough.
If you are thought to be at greater risk of stone formation, then we will offer to work with you to create a personalized program to prevent stone formation in the future. In addition to a stone analysis (it’s important that you catch the stone and bring it to your doctor!), blood studies and a 24 hour urine collection can help direct to your personalized medical therapy. There are many metabolic causes of stones, in various combinations, and we will determine your specific metabolic problem and work with you to address it with diet or medications. If you have frequent stone recurrences, multiple medical problems, or additional urologic problems such as neurogenic bladder, chronic infection or obstruction, then our comprehensive program is particularly well suited for you.
Over the past 10 years the number of surgical procedures we perform for kidney stones has continually increased. Of the more than 1,000 procedures performed annually, ureteroscopy – which is a minimally invasive outpatient procedure that is also very versatile and effective – is our most common.
Cutting Edge Research
We actively participate in research for developing newer methods and techniques for treating kidney stones. We also study therapy trends, quality of care and effectiveness of treatments to improve the understanding of kidney stones and the level of care for all stone patients. As a patient you are eligible to participate in active clinical trials that could be a benefit to your situation.