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Urinary tract stone management

Urinary tract stones are frequent and they affect 2-3% of the world's population with twice as many men affected than women. When affected by a urolithiasis, the chance of recurrence is around 50%. Why do urinary tract stones form and how can they be treated?


What is the urinary system and how does it work?

The urinary tract, or system, consists of the kidneys, ureters, bladder and urethra. The kidneys are two bean-shaped organs that maintain balance by removing extra water and wastes from the blood and converting it to urine. Urine is carried by narrow muscular tubes, the ureters, from the kidneys to the bladder, a reservoir in the lower abdomen. The bladder's walls stretch and expand to store urine and then flatten when urine is emptied through the urethra outside the body.

Arbre urinaire

What is a kidney stone?

Kidney stones form when there is an imbalance of chemical substances (calcium, oxalate, phosphate) in the kidneys. This imbalance causes abnormal crystallization of minerals that end up forming a kidney stone. The stone starts very small and grows if it does not pass into the urine flow when it is still small enough to go through the ureter without any problem. When the stone grows bigger inside the kidney, it can block off the urine flow out of the kidney or can make its way down to the ureter until it meets a narrow part of the ureter and blocks the urine flow.


What are the symptoms?

The most common symptom of a kidney stone is extreme pain. The pain occurs when the stone is blocked while travelling down the ureter and is due to irritation and contractions of the ureter muscles trying to force the stone down. Typically, 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. Sometimes a person will also have blood in the urine, nausea and/or vomiting.
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.
If fever or chills accompany any of these symptoms, there may be an infection and you should contact your urologist immediately.


Who gets kidney stones and why?

Urinary calculi have plagued men for centuries (men develop stones twice as often as women) and some individuals are predisposed due to inherited biochemical or anatomical factors and may be more susceptible to environmental influences.
Roughly 2-3% of the world population suffers from kidney or urethral stones during their lifetime.
Kidney stones usually form in people aged between 20 and 40 years. There is a 50% chance that someone who has a kidney stone once will form another one in the future.
The exact causes of urolithiasis are not well understood. The primary way to prevent kidney stones is to drink plenty of fluids, ideally water. A high volume of fluid moving through the urinary tract keeps small crystals moving through the kidneys and decreases the likelihood of a stone developing.


Calcium oxalate stones form because of an excess of calcium and other minerals on the urine and represents 80% of all urinary tract stones.


Some kidney stones (struvite, uric acid, calcium phosphate and cystine stones) are associated with other conditions.

The formation of struvite stones is associated with the presence of a bacteria, that are capable of splitting urea into ammonia, decreasing the acidity of the urine and resulting in favorable conditions for the formation of struvite stones. Struvite stones are always associated with urinary tract infections.

The formation of uric acid stones is associated with conditions that cause high blood uric acid levels, such as gout, leukemias/lymphomas treated by chemotherapy (secondary gout from the death of leukemic cells), and acid/base metabolism disorders where the urine is excessively acid resulting in uric acid precipitation.

The formation of calcium phosphate stones is associated with conditions such as hyperparathyroidism and renal tubular acidosis.

The formation of cystine stones is uniquely associated with people suffering from cystinuria, who accumulate cystine in their urine.


How can kidney stones be treated?

Treating kidney stone disease depends largely on the size, position and number of stones in your system. The majority of small stones will not cause infections, blockages or symptoms, and will pass if you simply drink plenty of fluids each day. Only an appropriate healthcare professional can decide whether treatment is required, and, if so, what kind of treatment should be recommended. If you are interested in ESWL you can ask your Doctor for more information, and explore our website.

Extracorporeal Shock-Wave Lithotripsy:ESWL
For a majority of cases, surgical manipulation is not necessary, but exact identification of the stone(s) and rigorous patient selection is important for accurate treatment of the disease.

Extracorporeal Shock Wave Lithotripsy (ESWL) is a non-invasive technique for disintegration of urinary calculi. Since its introduction in clinical practice more than 20 years ago, ESWL has become the standard treatment for urinary calculi. This treatment reduces stones to sand-like fragments using shock waves created outside the body by a lithotripter, targeted directly to the stone. This method does not damage surrounding body tissue and only breaks the stone. The technology is only effective if the kidney is functioning well and there is no blockage to the passage of stone fragments. As a non-surgical procedure this technique, which requires little analgesia and no hospital stay, is an ideal treatment alternative for patients suffering from urolithiasis.
Most devices use either X-rays or ultrasound to help the surgeon pinpoint the stone during treatment. In most cases, shock-wave lithotripsy is done on an outpatient basis without anesthesia. Recovery time is short and most people can resume normal activities in a few days.
After ESWL treatment, the sand-like particle will pass through the urine. A patient may experience some discomfort if the fragments produced are larger.
EDAP TMS' 4th generation of shock wave lithotripters, featuring the patented Electroconductive technology, fragments stones into very fine particles that will easily pass through the urine without causing discomfort.

Percutaneous nephrolithotomy (PCNL)

This procedure is the treatment of choice for patients with larger kidney stones in a location that prevents effective use of shock-wave lithotripsy or that causes a blockage so severe that the stones cannot be bypassed using a stent.
In this procedure, the surgeon makes a tiny cut in the flank area and then uses an instrument called a nephroscope to locate and remove the stone. For larger stones, a type of energy probe (ultrasonic, electrohydraulic or hydraulic) may be needed to break the stone into small pieces. All of this is done while the patient is sedated or under anesthesia.
One advantage of this procedure over SWL is that the surgeon removes the stone fragments instead of relying on their natural passage via the ureters. Generally, patients stay in the hospital for two or three days and may have a small catheter in the kidney during the healing process. Most patients can resume light activity in one or two weeks.

Ureteroscopy (URS)
Although some kidney stones in the ureters can be treated with shock-wave lithotripsy, ureteroscopy may be needed for mid- and lower-ureteral stones. In fact, this will be the preferred method to treat lower-ureteral stones. Ureteroscopy involves the use of ureteroscopes, small flexible or semi-rigid telescopes that can be inserted up the urethra, through the bladder and into the ureter without an incision. These instruments allow the doctor to view a ureteral stone directly. They also have small working channels through which various devices can be passed to remove or fragment the stone. Anesthesia is generally used, and a stent is left in the ureter for a few days after treatment while healing takes place. Ureteroscopy was developed in the 1970s and became more widely used during the 1980s. The risks of ureteroscopy include perforation of the ureter or the formation of strictures (scar tissue), especially if the stone has been impacted or embedded within the wall of the ureter for longer than two months. The majority of ureteroscopic procedures can be performed as day surgery and most individuals can return to work within one or two days of the procedure.

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