Kidney Stone


Urinary Stones have affected mankind for centuries and has been the silent cause of renal failure. Even in the 4th century BC, Hippocrates (father of modern medicine) wrote in his Hippocratic oath "… I will not cut, even for stone, but leave such procedures to the practitioners of the craft." The speciality of "urology" has been recognized ever since. And the surgeons who treat urinary stones and other urinary diseases are called "Urologist".

Kidney Stones

(Synonyms - Renal Calculi, Calculus Disease, Stones - Kidney, Urinary Stones)

The kidneys are solid; bean shaped, reddish brown-paired structure, which lie behind the abdominal cavity one on either side of the vertebral column. This kidney acts like the filter organ, which removes the waste products from the blood, which forms urine. The kidney also helps in maintaining elctrolyte balance.

About 180 litres of blood, which run through these nephrons (functional unit of the kidney), are reduced to urine by the process of filtration, reabsorbtion, and secretion by the nephrons. The urine enters the pelvis of the kidney where it collects and continues down the ureters to the bladder. In the urinary bladder urine is temporarily stored and is finally eliminated from the body through urinary passage called urethra. Human beings on an average pass about 1 to 1.5 litres of urine per day.

Kidney stones constitute one of the commonest diseases in our country and pain due to kidney stones is known as worse than that of labour pain. In India, approximately 5 -7 million patients suffer from stone disease and at least 1/1000 of Indian population needs hospitalization due to kidney stone disease.

Urinary Stones - Geographical Distribution

The kidney stone disease is widespread particularly in countries with dry, hot climate. These "stone belt regions" of the world are located in countries of Middle East, North Africa, the Mediterranean Regions, North Western state of India and Southern State of USA and areas around the great lakes.

In India, the "stone belt" occupies parts of Maharashtra, Gujarat, Punjab, Haryana, Delhi and Rajasthan. In these regions, the disease is so prevalent that most of the members of a family will suffer from kidney stones sometime in their lives. Removal of Kidney, Ureteric and Bladder stone procedure forms one of the commonest procedures in Urology department of the hospitals in these regions.

Kidney Stones - Causes

Apparently, there are no direct causes for stone formation. However, there are few hypothesis in this regard.

1. Kidney Stones can be formed any where in the urinary system, like kidney, ureter, and bladder. The process by which the stone formation occurs is Supersaturation of urine.

2. Hereditery: This may have some role as some people in the same family are more prone to form kidney stones.

3. Diet : Diet is not a dominating factor. However, if an individual is a stone former the diet rich in calcium, oxalated & uric acid may increase the chances of stone fornation. In normal individual, diet will not play much role. More than the diet; water intake may be more responsible for kidney stone formation.

4. Water Intake: If an individual is a stone former then an increased intake of water will help him pass small gravels before they become nidus for stone formation. Unfortunately, in stone belt region due to dry climate the water is hard and will infact contribute to the formation of stones, if taken in large quantities.

5. Medications: Medications like diureteric, excess calcium containing antacids or calcium pills will increase the chances of forming stones.

6. Other chronic medical illness Some chronic illness are associated with kidney stone formation specially cystic fibrosis, renal tubular acidosis and inflammatory bowel diseases etc are associated with increased risk of kidney stones formation.

Natural History of Stone Formation

Virtually all stones are formed in the kidneys, initially as small particles. These particles grow within the kidney to varying sizes, often filling up the whole kidney as a branched stone (the staghorn calculus). Sometimes they move out of the kidney when relatively small, and then migrate down the ureter into the bladder. Some stones less than 5 mm in size pass out spontaneously, but occasionally they migrate down the ureter & they may block the ureter causing obstruction to the flow of urine. This results in pain, which may be very severe (ureteric colic). Nausea and vomiting can also be associated with the colic pain. Some stones reach the bladder, and lodge there, growing larger and larger. Rarely they block the urethra causing a painful retention of urine.

Types of Urinary Calculi ( Urinary Stones)

There are various types of urinary stones, but the most common ones are

  • Calcium oxalate.
  • Uric acid.
  • Struvite.
  • Cystine stones

Renal Calculus can be diagnosed with following symptoms and signs:

  • Incidental diagnosis on routine health checkups.
  • Dull aching pain in the back
  • Acute colic.

Classical colicky pain is described as pain that begins from the flank or the side of mid-back and comes forwards to the groin (from loin to groin), accompanied by nausea, vomiting and gaseous distension.

  • Urinary tract infection.
  • Increased frequency of urine
  • Pain and or burning while passing urine.
  • Passage of blood in urine (Haematuria) which can be gross or detected in the Urine test.


A through physical examination is very important to understand the site and nature of the pain. It would also give the doctor an idea as to whether the pain is likely due to a stone within the urinary system or due to other reason.

To diagnose stone formation:

1. Urine routine which will show:

  • Crystals in urine.
  • Blood cells in urine
  • Pus cells in urine.

2. Urine Culture colony count & sensitivity test to rule out the urinary tract infection and to select the best antibiotic that will treat the infection if present.

3. X-Ray KUB

  • To detect size and site of stone

4. Ultrasonograpy of kidney, ureter, and bladder.

  • To show the size of the kidney & swelling (Hydronephrosis) of the kidney in obstructive uropathy. It will also show ureters if they are dilated. However, it does not give information about the function of the kidney.
  • Will also screen other abdominal organ for any pathology.

To plan treatment once kidney stone is diagnosed

1. Blood test to look for normal functions of the kidneys

  • Serum Createnine.
  • Serum Blood Urea.
  • Serum Electrolytes.

2. Intravenous Urography (IVU)

This is the specialized test were series of X- ray are taken after injecting the special medicine, a dye - Contrast, which has radiopaque property. The kidneys excrete these contrasts and kidneys are outlined on X rays and serial films are taken. This is a very useful test. It gives lot of information including size and shape of kidneys, function of kidney - comparative and individual, presence of obstructive uropathy, delineates the anatomy of kidney, ureter & bladder etc.

3. CT scan of Abdomen & Pelvis - CT Urography

CT scan of the abdomen & pelvis can be done with or without oral or intravenous contrast. The CT scan can demonstrate anatomy of the Kidney , Ureter and Bladder and can detect a stone, its location, its size and whether is causing obstruction to the ureter leading to its dilatation. It also gives an idea about other intra-abdominal organs like liver, pancreas, appendix, gall bladder, aorta & bowel. CT Scan without contrast has same limitations.

2. Test to find out the cause of the urinary stone disease.

Metabolic tests may have to be done to look for any defects in your body, which may be responsible for kidney stone formation. This is important, as it is not only sufficient to treat for the kidney stone but to find out why kidney stone has been formed. The recurrence of kidney stone formation can be prevented. Therefore, an appropriate treatment can be given so that one does not form kidney stones again.

  • Serum Calcium
  • Serum Phosphorus.
  • Serum Uric acid
  • 24 hour urinary calcium / 24 hrs urinary uric acid
  • Stone analysis of the retrieved calculus.

Treatment of Renal Calculi

It has been said that "once a kidney stone former, always a kidney stone former". Once a kidney stone has been diagnosed, the choice is between expectant treatment and more aggressive forms of treatment, such as transurethral, percutaneous, or opens surgeries or extra corporeal modalities. Although some kidney stones may pass spontaneously and unless complicating conditions arise, surgical intervention may not be necessary. Thus, identification of kidney stones that are likely to pass is of utmost importance.

The primary decision is whether to apply surgical treatment or wait. Removal of kidney stones by any methodology is necessary when there is evidence of:

  • Significant obstruction
  • Progressive deterioration of the kidney
  • Irreversible infection of the kidney (Refractory pyelonephritis)
  • Unremitting pain
  • Stone obstruction an infected kidney requires emergency intervention

Various general and specific medical measures are used to treat the kidney stone disease. A significant percentage of patients will at sometimes or the other require intervention for the recovery of the urinary stone.

Urinary Calculi - Conservative Management

Most kidney stones of small size pass spontaneously in the urine without any need for intervention. The probability of a kidney stone passing down spontaneously will depend upon the size of a stone, its location, shape etc. Such patients are treated symptomatically with:

  • Anti-biotic to control infection.
  • Analgesics to give relief from the pain
  • Oral Hydrotherapy. The patient is generally instructed to maintain a high fluid intake ranging from 2 to 3.5 litres/day so that they can produce at least 2-2.5 liters of urine in 24 hours.
  • If the colic is severe and associated with the nausea, vomiting, fever then such patients are treated with Intravenous saline to produce adequate amount of urine so that kidney stone can be flushed out.
  • Endoscopic procedure is carried out like DJ Stenting, Ureteroscopy in some cases where the urinary stone causes severe obstruction and infection.

Treatment of Urinary Calculi:

  • Extra Corporeal Shock wave Lithotripsy (ESWL)
  • Ureterorenoscopy (URS)
  • Percutaneous Nephrolithotomy (PCNL)
  • Retrograde Intrarenal Ureteroscopic Surgery (RIRS)
  • Open surgery.

Extra Corporeal Shock Wave Lithotripsy (ESWL)

Extra Corporeal Shock Wave Lithotripsy (ESWL) is a preferred mode of treatment for kidney stones upto 1.5 cm in size. An IVU is done prior to ESWL treatment to confirm the open passage from kidney to bladder for the finer fragment to pass out after a successful ESWL treatment. ESWL machine uses highly focussed sound wave projected from outside the body to break kidney stones. The stone is generally reduced to sand like particles which subsequently passes out in the urine. More than 1.5 cm to 2 cm stones generally requires more than one or two ESWL treatments. This procedure is done in all age groups even with Cardiac and Respiratory problems. An additional development of ultrasound attachment alongwith the X ray localization helps in treating all kinds of urinary calculi even if they are radioluscent. This procedure is an outpatient procedure and patient need not be hospitalised for this treatment of urinary calculus disease.

Post lithotripsy

After the procedure is complete, the patient is kept under observation for an hour then he is allowed to return home. He is asked to take plenty of liquid orally to maintain his urinary output to 2-2.5 litres per 24 hrs. He may require some antibiotics and some painkiller. It takes few to several weeks for final stone fragments to pass out through urine. The patient may experience some burning sensation and blood in urine for few days. The patient is generally advised to do routine urine test with X- ray KUB for 7-10 days.

The patient rests for a while and then is allowed to return home. Sometimes a "stent" is placed in the ureter if it is anticipated that the stone fragments may block the ureter after Lithotripsy. Repeat sessions of Lithotripsy may be required, usually not earlier than 3-5 days.

However, all urologists realize that Lithotripsy is sadly not an answer to many of the stones seen in day-to-day practice. The reason is that for stones that are more than 2 cms in size, branched stones and various other complicated situations. Lithotripsy is either not effective or is slow to work with patients needing multiple procedures and hospital visits. In these patients, other options should be considered. In an average practice in India, where patients present with advanced and neglected disease, at least 40% of kidney stones fall into this category. These larger stones are removed by other technique called Percutaneous Nephrolithotomy or PCNL.

Percutaneous Nephrolithotripsy (PCNL) - Synonyms - Tunnel Surgery, Key Hole surgery for Kidney Stones

PCNL treatment is for a larger stones which are not indicated by ESWL.This procedure is generally done under general anaesthesia, spinal and /or epidural anaesthesia. In this technique the stone is removed by making a small tunnel into the kidney from the back. A fine needle is used to puncture the renal collecting system with the aid of X-ray and/or Ultrasonograpy, and a guide wire is led into the kidney through the needle. This tract is dilated over the guide wire and a Nephroscope (kidney telescope) is inserted into the pelvis of the kidney. The stones are visualized, fragmented using Swiss Lithoclast and extracted using fine forceps, allowing the kidney to become free of stones at the end of the operation, in the vast majority patients. This is of course an operation, needing full general anesthesia, average 90 minutes of operation time, 3 -4 day hospitalization, and an occasional need for blood transfusion. Patient returns to light work in 5-7 days time. Nevertheless the operation is safe, for both the patients and the kidney. This operation has really reduced the need for open surgery (cutting surgery), which is now reserved for exceptional indications

This Percutaneous Nephrolithotomy (PCNL) technique is used to treat kidney stones of:

  • Large than 2.5 cms,
  • Staghorn calculus,
  • Calyceal diverticular calculus.

URETERIC STONE - Synonyms - Stone- Ureter, Ureteric calculus

The ureter is a thick walled narrow cylindrical tube which connects the kidney with the urinary bladder. The ureter is approximately 25 to 30 cm in length with 3 - 4mm diameter. It brings down the urine from the kidney into the bladder. The ureter is narrow at 3 junctions and urines passes through it in peristaltic waves. The backflow of urine into the kidney is prevented by ureterovesical valves.

Ureteroscopic Stone Removal

The Ureter is divided into 3 parts :-.

  • Upper ureter ( upper third )
  • Middle ureter ( mid third )
  • Lower ureter ( lower third )

Technique - Ureterorenoscopy (URS)

Ureteroscopy is highly successful procedure for the retrieval of stone in the ureter. This is a routine procedure performed by urologists. It is passed through the normal urinary opening through the bladder into the ureter. The most common indication is to treat ureteric calculi specially the once which cannot be treated by ESWL or conservative treatment. This is also used for the diagnosis of any malignant lesion in the ureter. Ureteroscopy are of two types:

  • Rigid Ureteroscopy
  • Flexible Ureteroscopy

Ureterorenoscopy (URS) involves the passage of an instrument namely Ureteroscope through normal urinary passage. The instrument is as thick as a pen and is about 40 cm long. The Ureterorenoscope is advanced under vision through the normal urinary passage under anesthesia. The Ureterorenoscope is advanced on the side of the ureteric stone and up to the ureteric stone. Once the ureteric stone is localized, various options are available. If the ureteric stone is small, it can be picked up by the forceps & pulled out. But, if the ureteric stone is larger, the ureteric stone can be broken into tiny fragments using Swiss lithoclast or ultrasound or even a combination of both as in Swiss Lithoclast master or even Laser. A variety of other instruments can be passed in through the scope, which can be used to break the stones and remove them. Patients have to be admitted in the hospital for a day or two for this procedure and it has to be done under anesthesia. Double J stent is usually kept post procedure to drain the kidney. It is a very safe procedure in experienced hands and Ureterorenscopy can treat almost all the ureteric stones. URS is often used as a diagnostic tool for stones as well as a diagnostic tool for ureteric cancer (tumour). It is a minimally invasive method of treating kidney and ureteric stone.

Retrograde Intrarenal Ureteroscopic Surgery (RIRS)

Flexible Ureterorenoscopy is now available and this flexible ureteroscope can be passed through the normal ureter opening all the way up on the kidneys and stones in the calyces of the kidney can be fragmented into fine particles using laser technology. The stones are otherwise not responding to treatment or amenable by ESWL or PCNL or URS.

Therapeutic status of ESWL, PCNL, URS, RIRS

These techniques are not competitive with one another but are greatly complimentary to each other. Though ESWL is the ideal treatment for urinary calculi but in selected cases a combination of the above treatment modalities are much better off. Kidney stones up to 2-2.5 cms can be treated by introduction of Double - J stent and multiple sessions of ESWL therapy. However, kidney stones larger than 2.5 cms or partial or complete stag horn will do better with a combination of PCNL and ESWL. PCNL can be used to debulk the kidney stone mass and can be followed up with lithotripsy for residual fragments, if any are left behind. Impaction of stone fragments in lower ureter after lithotripsy may need URS. Stones which are not amenable to treatment by ESWL or PCNL or URS, can be treated by RIRS. Flexible URS is used to reach stone in the kidney through normal ureteric opening and th stones are fragmented using Laser technology. With the advancement of medical science and availability of these modalities, Open Surgery for the stone shall be rarely necessary. However, in certain selected cases, open surgery still remains the best modality of treatment.

Open surgery

With the advent of new technologies to treat kidney stone disease, the need for open surgery has been drastically reduced. However, in some cases it might be required. The type of open surgery will depend upon the site and size of the stone within the urinary tract.

BLADDER STONE - Synonyms - Blasser Calculi, Vesical Calculus.

The Urinary Bladder stones are generally formed as an effect of primary pathology. It is important to take care of primary pathology before treating the secondary bladder calculi to prevent the recurrence of bladder stone formation.

The Urinary Bladder is a storage organ which stores the urine coming from both the kidneys. When sufficient amount of urine is collected in the bladder, the sensation of fullness of bladder is perceived by the brain. The brain in turn orders the bladder to pass urine. The bladder stones are formed when there is an obstruction to the outflow of urine leading to stagnation into the bladder. This stagnation causes the salts and the minerals in urine to concentrate. This stagnation can occur due to an enlarged prostate or urinary tract infection.

Cause of Bladder Stone

These stones are usually associated with urinary stasis, but they can form in healthy individuals without evidence of anatomic defects, strictures, infections, or foreign bodies. The presence of upper urinary tract calculi is not necessarily a predisposition to the formation of bladder stones.

  • Bladder outlet obstruction remains the most common cause of bladder calculi in adults.
  • Prostatic enlargement.
  • Elevation of bladder neck.
  • High postvoid residual urine volume cause stasis, which leads to crystal nucleation and accretion

Symptoms of Bladder Stone

The presentation of vesical calculi varies from completely asymptomatict to the following symptoms

  • Suprapubic pain (lower abdominal),
  • Dysuria (pain while passing urine).
  • Intermittent flow of urine.
  • Increased frequency of urination,
  • Hesitancy.
  • Nocturia.
  • Urinary retention.


  • X-ray KUB will show the presence of the stone in the pelvis

  • Sonography will show the presence of the stone with clue to formation of bladder stone like enlarged prostate.


  • Transurethral Litholapaxy. 

    Cystoscopy is performed to evaluate lower urinary tract like urethra and prostate and finally to visualize the stone into the bladder. If the stone is small, it can be manually fragmented with the forceps and the fragments are removed through the cystoscope. 

  • Percutaneous Suprapubic Cystolithotomy.

    In case of larger bladder stone, the percutaneous suprapubic route is selected. This allows the use of shorter- and larger-diameter endoscopic equipment (usually with an ultrasonic lithotripter), which allows rapid fragmentation and evacuation of the calculi. Often, a combined transurethral and percutaneous approach can be used to aid in stone stabilization and to facilitate irrigation of the stone debris. The holmium laser is also effective but is generally slower, even with the 1000-micron fiber. 

  • Open Suprapubic Cystolithotomy.

    This procedure become the preferred mode of treatment for very large or multiple bladder calculi associated with enlargement of prostate.

Dilip Raja