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Kidney Stones

Kidney Stones

London Urology is renowned for its treatment of Kidney Stones, offering a rapid-access kidney stone service using the latest techniques and state-of-the-art technology to allow patients the best possible recovery. Patients can rest assured that they are under the care of two of the county’s leading experts in kidney stones, Mr Leye Ajayi and Mr Simon Choong.


Kidney Stones

Our Kidney Stones service is run by London Stone Unit, which was set-up by London Urology to provide rapid-access diagnosis, treatment and recovery for kidney stone patients.

The Kidneys

Kidney Stones Anatomy

The kidneys – bean shaped organs – lie on each side of the spine, near the middle of the back and just below the ribcage. The ureters are tubes which connect the kidneys to the bladder and transport the urine produced by the kidney to the bladder for storage.

The kidneys perform many functions to keep the blood clean and chemically balanced by processing blood to remove waste products and excess water that becomes urine. As well as removing waste products the kidneys also release three important hormones:

  • Erythropoietin – stimulates the bone marrow to make red blood cells
  • Renin – regulates blood pressure
  • Bioactive Vitamin D – the active form of vitamin D, which helps maintain calcium for bones and for normal chemical balance in the body

Kidney Stones Specialist

We are a dedicated centre for the treatment and prevention of kidney stones, offering an acute service normally seeing patients within 24 hours of first contact.

Most stones are formed in the kidney and some can then travel down the ureter (a long and narrow tube connecting the kidney to the bladder) and into the bladder. Occasionally a stone will form in the bladder itself, in the presence of bladder outflow obstruction, such as an enlarged prostate gland. Stones in the kidney or ureter can cause blockage of urine flow and can lead to excruciating pain.

In the presence of an obstructed kidney or an infection (high fever), a patient must seek immediate medical attention.

There are a number of theories surrounding the formation of kidney stones. Some people also appear to have a tendency toward stone formation for different reasons. Once you have formed a stone, there is an increased risk of you forming more stones.

Symptoms Of Kidney Stones

Often, when stones are located in the kidneys, there are no symptoms and it is only when they travel down into the more constricted space of the ureter that acute pain develops. Pain tends to develop in the kidney if the stone becomes large enough to block the flow of urine. Symptoms may include the following:

  • Renal colic – severe loin pain starting in the small of the back below the ribs or in the lower abdomen, which can also travel to the groin. The excruciating pain can last for a few minutes or hours with short periods of relief.
  • Feeling nauseous and possibly vomiting.
  • Bloody or cloudy urine.
  • Burning sensation when urinating.

Types Of Kidney Stones

  • Calcium stones – the most common type of kidney stone, made from calcium and oxalate, or calcium and phosphate.
  • Struvite, or infection stones – contain magnesium and ammonia, can be horn-shaped and quite large.
  • Uric acid stones – smooth, brown and tend to affect people who eat a diet which is high in protein.
  • Cystine stones – often yellow and crystal shaped.

Diagnosis Of Kidney Stones

You will be asked about your symptoms and diet. A diagnosis will need to establish the exact size, location and type of kidney stone you have. The investigations, using radiological imaging, such as a CT scan, will diagnose the site and size of the stone and the degree of kidney blockage, and can usually be done quickly during the first visit.

Other Tests May Include:

  • Urine test for infection.
  • Blood tests to show whether you have high levels of certain chemicals linked to kidney stones.
  • X-rays – stones containing uric stones are usually not seen on x-rays.
  • Ultrasound scan of the urinary tract.
  • IVU – Injection of a special dye which shows up on x-ray.
  • CT scan – no injection is involved and it only takes two minutes

Causes Of Kidney Stones

At London Urology we offer patients Metabolic Stone Screening. This investigation (non-invasive, it requires the patient to collect all urine that is passed within two consecutive 24hr periods) will determine the reason that kidney stones are being formed in the first place. This is turn will help the Consultant to advise on preventing the formation of further kidney stones. Over 50% of kidney stone patients will form another stone in the next 10 years.

Genetics: In approximately 25% of cases the cause is genetic, where there is usually a family history of kidney stones.

Geography: Chronic dehydration is a major cause in the formation of stones because many people do not drink enough fluid and those living in hot climates are more susceptible to kidney stones.

Stress: Lifestyle strains and stresses are a big cause of kidney stone formation, often combined with chronic dehydration.

Diet: A high protein diet, or a diet high in oxalates, phosphates and other minerals, can increase the risk of uric acid stones.

Treatment Of Kidney Stones

Kidney Stones Treatment

If stones are left untreated, they can cause serious damage to the kidney, so it is important to seek medical help if you are experiencing any symptoms.

London Urology at the Hospital of St John and St Elizabeth provides several methods for treating kidney stones, including non-surgical treatment, non-invasive Lithotripsy, minimally-invasive lasering via Ureterorenoscopy and keyhole Percutaneous nephrolithotomy (PCNL). Your consultant will discuss with you the best form of treatment.

Pain relief is the first priority and there has been a trend toward the use of anti-inflammatory agents (NSAID). Not all patients require hospital admission. However, it is mandatory in some circumstances, especially in the presence of infection and kidney blockage.

Our trusted Consultant Anaesthetists, from London teaching hospitals, are all experts in their fields, with an established history of specialism in kidney surgery, along with our team of nurses, who have been treating patients with stones for many years, offering clinical expertise as well as sound advice and reassurance throughout the entire treatment process.

Find out more with our Kidney Stones FAQ.

Kidney Stones Surgery

In this video, Mr Leye Ajayi, a Consultant Urological Surgeon at London Urology performs a right percutaneous nephrolithotomy with endoscopic and combined renal surgery, to treat a complex kidney stone. Mr Ajayi utilities the latest surgery methods combined with state-of-the-art facilities at the Hospital of St John & St Elizabeth to allow for the best possible surgical results and most comfortable patient experience.

Digital Flexible Ureterorenoscopy

Kidney stone patients at London Urology can look forward to a shorter operation thanks to a recent investment in the latest state of the art digital technology.

Mr. Leye Ajayi, one of our leading urologists, said “By replacing our older equipment with two new FLEX-XC™ digital flexible ureterorenoscopes, procedures are much quicker, very precise and I can take on large stones thanks to a higher resolution digital image.”

Mr. Ajayi continued “The large magnified view also lets me see and retrieve the tiniest of kidney stone fragments allowing for an excellent stone clearance rate.”

Unlike previous instruments which relied on fibre optics for vision, the new FLEX-XC™ has a digital camera chip mounted at its tip and at less than 3mm in diameter, is the smallest of its kind on the market. In a minimally invasive procedure, the FLEX-XC™ is passed into the bladder and up the ureter (a long and narrow tube connecting the kidney to the bladder) into the kidney. Any stones are fragmented using laser energy and then retrieved in small baskets.

Flexible Ureteroscopy using the FLEX-XC™ is provided by Mr. Leye Ajayi and Mr. Simon Choong, consultant urologists and experts in stone disease at London Urology.

London Urology – Kidney Stones Specialists

Mr. Leye Ajayi and Mr. Simon Choong are experts in the diagnosis and treatment of kidney stones and have access to the latest diagnostic equipment at the Hospital Of St John & St Elizabeth. To ask a question or to book an initial consultation you can call us on 020 7432 8297 or email us at


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