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Kidney and ureteral stones are among the most painful and prevalent of urologic disorders. More than a million kidney stone cases are diagnosed each year, with an estimated 10 percent of Americans destined to suffer at some point in their lives. This number is unfortunately rising secondary to the dietary and climate changes in our population.
Did you know that Austin and Central Texas is conveniently located in the “Stone Belt” of the USA? This is an area approximating a “belt” that goes across the southern part of America. Theories include the higher temperatures, increased sweat and dehydration, and more minerals in the water supply. Lucky us! Fortunately, many patients who are diagnosed with a ureteral stone will be able to pass their stone without any intervention or surgical procedures.
However, if you are not so lucky as to pass your stone spontaneously, Dr. Shaw and Dr. Tsai have extensive experience in quickly evaluating and treating kidney or ureteral stones in the fastest, most minimally invasive method possible. Getting you back on your feet is our number one priority.
Once your kidney stone is treated, Dr. Shaw and Dr. Tsai’s number one goal is for you to never have a stone again! Dr. Shaw and Dr. Tsai pride themselves on performing a thorough exam which includes a simple urine study, as well as analyzing the stone itself with photospectrometry (whew!) to find out why you make the stone, and stop or reduce it from happening again. That’s our goal, no more stones. Although some patients are more challenging than others, he has patients who used to form several stones a year, who no longer do!
The urinary tract is similar to a plumbing system, with a series of special pipes that transport water and salts through the body. A normal urinary tract includes two kidneys, two ureters, the bladder, and the urethra. The kidneys act as a filter system for the blood, cleansing it of poisonous materials while retaining valuable sugars, salts and minerals. Urine, the waste product of the filtration process, is produced in the kidney and continuously trickles through two 10 to 12-inch long tubes called ureters, all the way from the kidney to the bladder. The ureters are about one-fourth of an inch in diameter and their muscular walls contract to make waves of movement that forces urine into the bladder. The bladder is an expandable structure, and stores the urine until it can be conveniently disposed. The tube through which the urine flows out of the body is called the urethra.
A stone forms in the kidney when there is an imbalance between certain urinary components, chemicals such as calcium, oxalate and phosphate, which promote crystallization and others that inhibit it. Most common stones contain calcium in combination with oxalate and/or phosphate.
A less common type of stone is caused by infection in the urinary tract. This type of stone is called a struvite or infection stone. Less common are the pure uric acid stones. While kidney stones are in general hereditary, there is one in particular, called the cystine stone, that is passed through genes, however is very rare. Even more rare are those linked to other hereditary disorders.
A ureteral stone is a kidney stone that has left the kidney and moved down into the ureter. The stone begins as a tiny grain of undissolved material located where urine collects in the kidney. When the urine flows out of the kidney, this grain of undissolved material is left behind. The material deposited is usually a mineral called calcium oxalate; there are other, less common, materials that may also form a kidney stone such as cystine, calcium phosphate, uric acid and struvite. Over time, more and more undissolved material is deposited, and the stone progressively becomes larger. Most stones enter the ureter when they are still small enough to pass down the entire ureter into the bladder. From there, the stone passes out of the body with urination. Some stones, by the time they leave the kidney, have grown too large to pass through the entire ureter. Such stones may become lodged in a narrow part of the ureter, causing pain and possibly blocking the flow of urine. These stones may need to be treated.
The number of people in the United States with kidney stones has been increasing over the past 20 years. Caucasians are more prone to develop kidney stones than African Americans. Although stones occur more frequently in men, the number of women who get them has been increasing over the past 10 years, causing the ratio to change. Kidney stones strike most typically middle-aged men but we are now seeing all ages and more females affected by stone disease likely secondary to the dietary and climate changes in our population. If a person forms a stone, there is a 50 percent chance they will develop another stone.
A number of risk factors play major roles in stone formation. The first is loss of body fluids (dehydration). When one does not consume enough fluids during the day, the urine often becomes quite concentrated and darker. This increases the chance that crystals can form from materials within the urine, because there is less fluid available to dissolve them. Stone formers should maintain 2 liters of urine output every day. Diet – A high-protein diet can cause the acid content in the body to increase. This decreases the amount of urinary citrate, a “good” chemical that helps prevent stones. As a result, stones are more likely to form. A high-salt diet is another risk factor, as an increased amount of sodium passing into the urine can also pull calcium along with it. The net result is an increased calcium level in the urine, which increases the probability for stones. Intake of oxalate-rich foods such as leafy green vegetables, nuts, tea or chocolate may also worsen the situation.
Medical conditions – Certain bowel conditions can also increase the risk such as chronic diarrhea, Crohn’s disease, and gastric bypass surgery.
Family history – Family history of stones, especially in a first-degree relative (parent or sibling), dramatically increases the probability of having stones.
Obesity – While kidney stones may be formed with certain diseases and medications, much of that rise can be attributed to poor dietary habits, and the growing rate of obesity. Because kidney stones are caused by what we eat and our lifestyle, they are prevented through the same mechanisms well.
Kidney stones usually cause pain and other symptoms once they are out of the kidney and making their way down the ureter. The typical symptom of a kidney stone is extreme pain that has been described as being worse than child labor pains. The pain often begins suddenly as the stone moves in the urinary tract, causing irritation and blockage. Usually, a person feels a sharp, cramping pain in the back and in the side of the area of the kidney or in the lower abdomen, which may spread to the groin. Also, sometimes a person will complain of blood in the urine, difficulty voiding, nausea and/or vomiting. Occasionally stones do not produce any symptoms. But while they may be “silent,” they can be growing, even threatening irreversible damage to kidney function. More commonly, however, if a stone is not large enough to prompt major symptoms, it still can trigger a dull ache that is often confused with muscle or intestinal pain.
If the stone is too large to pass easily, pain continues as the muscles in the wall of the tiny ureter try to squeeze the stone along into the bladder. One may feel the need to urinate more often or feel a burning sensation during urination. In a man, pain may move down to the tip of the penis. If the stone is close to the lower end of the ureter at the opening into the bladder, a person will frequently feel like they have not fully completed urination.
Stones as small as 2 mm have caused many symptoms while those as large as a pea have quietly passed. If fever or chills accompany any of these symptoms, then there may be an infection. You should contact your urologist immediately.
Stone size is an important consideration when dealing with a ureteral stone (stone that is out of the kidney and passing). Although some stones as small as 2mm have caused many symptoms while those as large as a pea have quietly passed, the general rule however is that stones 5 mm or less are more likely to pass without the need for intervention, and stones larger than 5 mm are unlikely to pass spontaneously. If the pain is persistent, continues to worsen or you have fever/chills these are signs that the kidney stone needs to be managed quickly. These can also be signs of a kidney infection which can become serious in the setting of a kidney stone if left untreated.
You should notify your urologist if any of the above symptoms occur.
Sometimes “silent” stones (those that cause no symptoms) are found on X-ray or CT scan that are done for other reasons. These stones would likely pass unnoticed. If these incidentally detected stones are large, then treatment may be considered. More often, though, ureteral stones are found on imaging obtained when someone who complains of blood in the urine or sudden pain. These diagnostic images give the doctor valuable information about the stone’s size and location. Blood and urine tests can also help detect any abnormalities that might complicate the management of the stone. If your doctor suspects a stone but is unable to make a diagnosis from a simple X-ray, he or she may scan the urinary system with computed tomography (CT).
Treating kidney stone disease depends largely on the size, position and number of stones that are present. Luckily, the majority of small stones (5 mm in diameter or less) will pass if you simply drink plenty of fluids each day. Consuming two to three quarts of water increases urine production, which eventually washes the stones out of the system. Once a stone has passed, no other treatment is necessary. It is always helpful to capture the passed stone, if possible, so that it may be analyzed to see what it is made of. Recent studies suggest that the majority of stones (95 percent) that are capable of spontaneous passage will pass within six weeks. After that time, continued observation is probably not warranted, and if the stone has not passed, further treatment will likely be needed.
The sudden pain that occurs when small stones start to move down the ureter can usually be treated with hydration, painkillers (anti-inflammatories and narcotics), and alpha blockers (medications that help relax the ureter). Some people may also need anti-nausea medications. Certain types of stones, such as those made of uric acid, can be dissolved with medical therapy. The majority, however, are composed of calcium and will not be dissolved with medicine alone.
Surgery should be reserved as an option for cases where more conservative approaches have failed. Surgery may be needed if a stone:
Historically, the surgical removal of a kidney stone involved an operation with an incision and an often lengthy recovery time. Today, though, most stones can be treated in a minimally invasive, or even non-invasive, fashion. As a result, recovery times are now measured in days, not weeks. Some of the treatments for kidney stones include:
Extracorporeal shock wave lithotripsy (ESWL®): ESWL® Is the most frequently used, non-invasive procedure for eliminating kidney stones. Shock wave treatment uses a machine called a lithotripter, which works by directing ultrasonic or shock waves, created outside your body (“extracorporeal”) through skin and tissue, until they hit the dense kidney stones. The impact of the shock wave causes stress on the stone; the cumulative effect of repeated shock waves is one of increasing stress on the stone, until eventually the stone crumbles into small pieces. These small pieces, about the size of grains of sand, usually pass easily through the urinary tract, and are voided out in the patient’s urine. Shock wave lithotripsy is generally used when the stone is not excessively large, the kidney is functioning well, and there is no blockage to the passage of stone fragments.
In the original ESWL® devices, the patient used to recline in a water bath while the shock waves were transmitted. Today, the machines are more compact and have a soft cushion on which the patient lies. Fluoroscopy is used to locate the stone and focus the shock waves.
In most cases, shock wave lithotripsy is done on an outpatient basis, and take about 30-45 minutes. Recovery time is short and most people can resume normal activities in a few days. Because of possible discomfort during the procedure, it is completed under general anesthesia. Once the treatment is completed, the small stone particles then pass down the ureter and are eventually urinated away. In certain cases, a stent may need to be placed up the ureter prior to SWL to assist in locating the stone or prevent the kidney from being obstructed by passage of stone fragments.
For certain larger stones, one ESWL® session by itself may not free the patient of all stone material. A repeat ESWL® session may be necessary. ESWL® is not the ideal treatment choice for all patients. Patients who are pregnant, obese, have obstruction past the stone, have abdominal aortic aneurysms, urinary tract infections or uncorrected bleeding disorders should not have ESWL®. In addition, certain factors such as stone size, location and composition may necessitate other alternatives for stone removal.
Certain types of stone (cystine, calcium oxalate monohydrate) can be resistant to SWL and may necessitate an alternative treatment approach. In addition, larger stones may not break up into pieces small enough to be discharged from the kidney. Stones located in the lower portion of the kidney also have a decreased chance of passage.
While shock wave lithotripsy is considered safe and effective, it can still cause complications. Most patients have blood in their urine for a few days after treatment. Bruising and minor discomfort in the back or abdomen from the shock waves are also common. To reduce the risk of complications, urologists usually tell their patients to avoid aspirin and other drugs that affect blood clotting for a period of time before treatment. Another complication may occur if the stone fragments cause discomfort as they pass through the urinary tract. In some cases, the urologist will insert a small tube called a stent through the bladder prevent this complication.
Ureteroscopy (URS): This treatment involves the use of a very small, fiber-optic camera called a ureteroscope, which allows access to stones in the ureter or kidney. The ureteroscope allows your urologist to directly visualize the stone by progressing up the ureter via the bladder. No incisions are necessary. It is an outpatient procedure, under general anesthesia, and usually takes about 45 minutes.
The camera is inserted through the urethra, then advanced through the bladder and up the ureter. Once the stone is seen through the ureteroscope, we will use either a laser to break up the stone, or a small, basket-like device can be used to grasp smaller stones and remove them. Once the stone has been completely treated, the procedure is done. In many cases, the urologist may choose to place a stent within the ureter, to allow any post-operative swelling or reaction to subside. The stent typically remains for 3-5 days and is removed in our clinic.
In URS, there is a small possibility that the ureteral wall could be damaged or torn during the procedure. If this occurs, placement of a stent for two to three weeks is usually sufficient to allow the damaged area to heal. A complete tear of the ureter is very rare and requires open surgery to repair.
Percutaneous nephrolithotomy (PNL): This procedure involves going directly into the kidney (by making an incision in the skin) to remove a stone. It is not typically used unless stones are larger, are in a location that does not allow effective use of SWL, or cause a blockage so severe that they cannot be bypassed using stent. Open surgery is the most invasive treatment and is rarely performed these days.
Sometimes a simple combination of medications will help you to pass your stone on your own (spontaneously) within 24-48 hours. When this is not possible, Dr. Shaw has the latest therapy including non-invasive shockwave-lithotripsy, or in other cases, we utilize the latest in High-Definition, LCD visualization systems combined with lasers to fragment, and remove those pesky stones. Fortunately, most therapies lend themselves to outpatient, day surgery. If ureteral stones do not pass in 6-8 weeks, a surgical intervention is generally needed to avoid potential damage to the kidneys and continued symptoms.
Although stone recurrence rates differ with individuals, in general you have a 50 percent chance of redeveloping stones within the next five years; so prevention is essential. Treatment results can vary depending on the selected treatment approach, as well as patient and stone specific factors. Many of our patients who are compliant with the kidney stone diet, do not continue to form the numerous and large stones they once had. There is a 24 hour urine study that we ask you to complete, that helps determine a customized prevention plan for you.
Our goal after surgery is to ensure that you do not produce future stones. The best way to prevent stone formation is mainly through diet. During your post-operative visit, we will discuss the kidney stone prevention diet in depth along with performing a 24-hour urine study. This study allows us to evaluate what elements in your urine contribute to increased risk of forming stones. Some key points to remember about kidney stone prevention include:
Any person with a family history of stones may be at higher risk. Stone disease in a first degree relative, such as a parent or sibling, can dramatically increase the probability for you. In addition, more than 70 percent of people with certain rare hereditary disorders are prone to the problem. Those conditions include cystinuria, an excess of the amino acid, cystine, that does not dissolve in urine and instead forms stones of cystine; and primary hyperoxaluria, an excess production of the compound oxalate, which also does not dissolve in urine, forming stones of oxalate and calcium.
Ureteroscopy with Basket/Laser and Stent: