Urinary Stones

Stones are formed from minerals excreted in the urine and the greater the concentration of the minerals the more likely they are to precipitate and form stones. There are also a number of natural stone inhibitors in the urine and low levels of these can result in a greater likelihood of stone formation.

Stones can also be associated with urinary infections, congenital kidney abnormalities and various medical conditions.

There are many different types of stones that can form. The most common ones are calcium and oxalate based. The type of stone formed is determined by biochemical analysis of the stone.

A/Prof Peter Royce and Mr Dennis King perform the treatments for urinary stones below at Cabrini Hospital Malvern, Cabrini Brighton, Epworth Eastern Hospital Box Hill and St. John of God Berwick, Melbourne Australia.

What Treatments Are Available ?

Many different treatment options are available for stone disease. The appropriate treatment is determined by stone and patient factors.

Observation

Many ureteric stones will pass spontaneously depending on the stone size, location and shape. Most stones that will pass do so within 6 weeks after symptoms have started. Ureteric stones 4-5mm in size have a 50% chance of spontaneous passage. You may be given a medication called Flomaxtra or Minipress to aid the passage of your stone.

Fibreoptic Pyeloscopy & Ureteroscopy With Holmium Laser

Fibreoptic pyeloscopy (intrarenal surgery) and ureteroscopy (intraureteric surgery) is indicated for the removal of kidney and ureteric stones. It involves the passage of a narrow telescope up the ureter to the stone and fragmenting the stone using the holmium laser. The larger stone fragments are then extracted using a basket device. The smaller fragments will pass spontaneously. Often a stent (a hollow tube placed between the kidney and bladder) is placed temporarily after the operation. This is removed in a separate procedure 2-4 weeks later.

You will be admitted to hospital usually on the morning of your treatment and remain in hospital as a day patient or overnight stay depending on factors such as distance from your home including country and interstate patients, ancillary procedures and degree of post treatment discomfort.

The operations is performed under a general anaesthetic administered by a specialist.

The ureteroscopy surgery take from 30 to 60 minutes, depending on the size and position of the stone.

There will be some discomfort with passing urine and there will be some blood present in the urine for several days after the treatment. In most people, the passage of the remaining stone particles is completely painless.

Laser Fragmentation of Ureteric Stone

Extracorporeal Shock Wave Lithotripsy

The modern treatment of kidney stones employs the use of a minimal invasive technology known as ESWL. ESWL results in the disintegration of kidney stones into small, sand-like particles, which are spontaneously discharged in urine. The treatment is performed using a machine called the Kidney Lithotripter. More than 1,000,000 patients have been treated world-wide, and its safety and effectiveness in eliminating kidney stones is well established. ESWL for kidney stones, represents a tremendous advantage to you, the patient, when compared to the conventional surgical treatment. ESWL is capable of fragmenting 90% of all renal stones, 10% of renal stones are too hard for even the Lithotripter to fragment.

Extracorporeal Shock Wave Lithotripsy

The ESWL treatment will take from 30 to 60 minutes, depending on the size of the stone. ESWL does cause minor bruising to the kidney and as a result blood will be present in the urine for several days after the treatment.

ESWL Procedure

In most people, the passage of the stone particles is completely painless. About 25-50% will experience some pain passing the stone particles and will require a tablet or injection to relieve the discomfort. In about 10%, the particles may cause a temporary blockage as they move from the kidney and travel down the ureter to the bladder. In this situation, a nephrostomy tube may need to be inserted into the kidney to temporarily drain the urine, while the particles pass through the system. Very rarely a haemorrhage may occur around the treated kidney, however, this is usually self limiting and rarely requires surgical treatment. It is important to cease taking Aspirin, Warfarin or any anticoagulant tablets, or inform us if you have a known bleeding tendency. There is some evidence that ESWL may elevate blood pressure in the long term, however, this remains scientifically unproven.

In some cases (about 30%) an additional procedure may be necessary prior to your ESWL treatment. This may involve inserting a Ureteric Catheter or Stent, which reaches from the bladder to the kidney, or performing a Percutaneous Ultrasonic Lithotripsy (PUL). A ureteric catheter is generally used for stones lodged in the ureter. PUL is done prior to ESWL for very large kidney stones, also known as staghorn stones. I will inform you if either of these additional procedures is necessary. The overall success rate for ESWL treatment in terms of complete stone clearance is 75-80%. Any residual stone fragments are usually small and not harmful. Larger stones 10-15mm diameter, or multiple stones may require a repeat ESWL treatment.

Following your return home you should adhere to the following advice :-

Resume normal activities as soon as you feel able.
Continue to drink 2.5 - 3.0 litres of clear fluid per day.
Undertake daily exercise to encourage spontaneous stone elimination.
Lie on your stomach at least initially, each night when retiring to bed.
Contact your surgeon if you experience either :-
- Fever above 38.5°C
- Unremitting pain, not controlled by pain relieving tablets eg.Panadeine.
Check you have an appointment for a follow-up X-Ray 2-3 weeks after your ESWL treatment, prior to review.
Also ensure you take your X-Rays home from hospital.

Percutaneous Nephrolithotomy (PCNL)

PCNL is used primarily for large stones in the kidney or upper ureter or as a salvage procedure for failed ESWL procedures or in situations where it not safe to proceed with ESWL.

This operation is performed under general anaesthesia and usually involves a hospital admission of 2-4 days.

This procedure is divided into 2 parts, access to the kidney and stone removal. This involves the creation of a passage from the skin surface to the inside of the kidney. Through this a hollow sheath is placed. This allows then the passage of a telescope into the inside of the kidney to visualise the stone. Through the telescope the stone is fragmented into small pieces which are then removed. Following stone removal a hollow drainage tube is placed to ensure adequate drainage of the kidney. This is removed within the next 24-48 hours.

Open Or Laparoscopic Stone Removal

These are uncommon operations to remove stones because of the ease and success of the less invasive stone treatments.

Stone Prevention

Having experienced first hand the pain and disability of a kidney stone, you will no doubt want to prevent the formation of further stones.

Stones recur in 50% of patients within 5-10 years, and the cause of kidney stones is usually multifactorial and varies from one patient to another.

Kidney stones form when the urine becomes super-saturated with crystals of calcium, oxalate, phosphate and urate. This occurs when there is increased production of these crystals in the urine, usually in combination with a low urinary volume, which results in an increased likelihood of kidney stone formation.

There are also inhibitors of crystal formation which are naturally produced by the body, and may be deficient in some people, and in turn this leads to stone formation.

Often there is a family history of kidney stones, and patients from a Mediterranean family background are also predisposed to an increased risk of kidney stone formation. This suggests a genetic tendency to stone formation, for which there is no known treatment.

Kidney stones commonly form during hot weather, suggesting that dehydration is a major factor, and in fact it has been well shown that increasing the urinary output from 800ml to 1,200ml per day will decrease the stone formation by 86%.

Other risk factors for stone formation include obesity and the consumption of a high animal protein diet.

There are several specific medical conditions such as renal tubular acidosis, hyperparathyroidism, gout, sarcoidosis, and medullary sponge kidney, which are directly related to the formation of kidney stones, and for which specific treatment may be indicated. In these patients medical treatment may include the prescription of allopurinol or thiazide diuretic tablets.

Treatment with potassium or sodium citrate has been shown to substantially reduce the recurrence of kidney stones in patients with low levels of citrate in the urine. Patients with renal tubular acidosis, chronic diarrhoeal states, and patients on thiazide diuretic therapy are all subject to hypocitraturia.

A small but specific group of people who form uric acid stones will benefit from alkalinisation of the urine with sodium bicarbonate, combined with allopurinol and a high fluid intake.

Uric acid stones may be both dissolved and prevented from further formation using this programme.

For most patients, however, a specific cause of stone formation will not be found despite metabolic investigations. In this situation, it is advisable to consume 2-3 litres of fluid per day, particularly during the summer months, in order to keep the urine dilute and prevent crystallisation. The water in Melbourne is not considered to be high in mineral content (hard water) and there is no need to drink distilled water or to filter your drinking water. Mineral water should be avoided, as it has a high mineral/calcium content.

It is advisable to avoid the excessive consumption of dairy food to that required for breakfast cereal, tea/coffee only.

Alcohol also tends to dehydrate the body and you should drink one glass of water for each glass of wine or beer consumed, in order to replace the fluid lost.

Soft drinks (except Coca-Cola), fruit juice, soda water, and tap water are the best forms of fluid replacement.

Cooking salt is known to increase the urinary production of calcium, and salt should therefore not be added to your food, either during cooking or at mealtimes.

Finally, if there is a structural abnormality to the drainage of your kidney, then corrective surgery may be required to allow the urine to drain freely from the kidney and prevent stone formation.