Kidney stones (calculi) are hardened mineral deposits that form in urine in the kidney. They originate as microscopic particles and develop into stones over time. Common kidney stones are,

Calcium Stones Approximately 85% of stones are composed predominantly of calcium compounds. Calcium stones are composed of calcium that is chemically bound to oxalate (calcium oxalate) or phosphate (calcium phosphate).
Struvite StonesThis type of stone, also called an infection stone, develops when a urinary tract infection persists in the kidney.
Cystine StonesCystine is an amino acid in protein that does not dissolve well. Some people inherit a rare, congenital (i.e., present at birth) condition that results in large amounts of cystine in the urine, called cystinuria
Uric Acid stones. Uric acid is the end product of protein. When excess of uric acid is secreted in the urine they form stones. They are associated with
non- vegetarian diet and some metabolic abnormalities.

RISK FACTORS
Several factors increase the risk for developing kidney stones, including inadequate fluid intake and dehydration, reduced urinary flow and volume, certain chemical levels in the urine that are too high (e.g., calcium, oxalate, uric acid) or too low (e.g., citrate), and several medical conditions, that blocks or reduces the flow of urine (e.g., urinary obstruction, genetic abnormality).

Treatment

If a kidney stone does not respond to medical treatment, surgery is considered. Urologists use several procedures to break up, remove the kidney stones.

A. Endoscopic treatment

UreteroscopyThis procedure can be used to remove or break up (fragment) stones located in the ureter. A long, thin telescope (ureteroscope) is inserted through the urethra and passed through the bladder to the stone. Once the stone is located, breaks the stone with a lithotriptor. The patient then passes the fragments. Ureteroscopy is performed under general or local anesthesia

B. LithotripsyIt is a method of breaking of stones in kidney, ureter and in bladder.
A powerful Dornier Lithotriper which uses both X-Ray and ultrasound localization for real time image. This allows the stone to be seen at all times during treatment. With this machine the patient needs only a light sedative and the pain is minimal. The lithotripter generates shockwaves, which crush dense stones into sand
like particles, which easily pass with urine.

• Electrohydraulic lithotripsy (EHL) uses a flexible probe to break up stones with shock waves. The probe is positioned close to the stone through a  ureteroscope. Small fragments can be passed by the patient or extracted.
• Extracorporeal shock wave lithotripsy (ESWL) uses highly focused impulses projected from outside the body to pulverize kidney stones anywhere in the urinary system. The stone usually is reduced to sand-like granules that can be passed in the patient's urine. Large stones may require several ESWL treatments. This is a OPD procedure and patient can be attending to his day to day work.

C. Percutaneous Nephrostolithotomy (PCN)

Percutaneous (i.e., through the skin) removal of kidney stones (lithotomy). A needle is inserted in to the kidney under radiographic control and guide wire is passed in to the kidney. Through this tract Nephroscope is passed and stone is fragmented and extracted.. This procedure achieves a better stone-free outcome in the treatment of medium and large stones than shock wave lithrotripsy.
     
D. Open Surgery

This procedure requires anesthesia. An incision is made in the patient's back and the stone is extracted through an incision in the ureter or kidney or bladder. This is done only in large stones.