Kidney Stones

Kidney stones form within the kidney. They are most commonly composed of a combination of calcium and oxalate, less commonly of uric acid or struvite. Small stones within the kidney are often completely asymptomatic. If the stone moves into the ureter (narrow tube leading from kidney to bladder) then severe pain (Renal colic) is experienced. Stones may also lead to kidney damage and infection.

Most small stones (<5mm) will pass through without surgery being required. If the stone does not pass through or is larger then an operation is required.

There are several surgical treatments, the most appropriate depends upon stone size and location. Stones within the kidney can be dealt with by flexible ureteroscopy + LASER, Shock Wave Lithotripsy and Percutaneous Nephrolithotomy. At your appointment we will discuss the best treatment for your particular circumstance.

Kidney Stone Prevention

People who have suffered from a kidney stone are usually very motivated to reduce their risk of another stone forming. The most common stones are composed of calcium oxalate and for these the usual dietary recommendations are:

  1. Increase your fluid intake. A good guide as to whether you are drinking enough fluid is to examine the colour of your urine – kidney stones form in concentrated urine so you should adjust fluid intake aiming for clear rather then yellow coloured urine.

  2. Reduce consumption of salt.

  3. Aim for a diet high in fruit and vegetables rather than meat.

  4. Do not restrict your intake of calcium – paradoxically doing this can increase the risk of another stone forming.

  5. If you are consuming large quantities of oxalate then reduce intake. Common reasons are: high nut consumption, also chocolate, rhubarb and spinach.

Stones composed of uric acid can be treated and prevented by increasing the alkalinity of the urine by taking ural sachets. Allopurinol is also prescribed to reduce uric acid production.

Tests

We will evaluate your stone-forming tendency with blood and urine tests and by analyzing the composition of the stone.

Useful Resource

http://my.clevelandclinic.org/urology-kidney/diseases-conditions/kidney-stones-overview.aspx

Ureteroscopy and Lasering of Stones

Ureteroscopy is performed to treat stones located within the ureter or kidney. Flexible scopes are used to inspect and treat stones within the upper ureter and kidney. Rigid scopes are used to treat stones within the lower ureter.

Procedure

Ureteroscopy is performed under a general anaesthetic. A long narrow telescope is inserted through the urethra, into the bladder then up into the ureter and kidney. Stones are treated by advancing a thin laser fibre through the ureteroscope and using the laser beam to fragment stones within the ureter or kidney. The larger stone fragments are then removed with a small basket.

Following stone treatment a temporary ureteric stent may be inserted. A ureteric stent is a thin flexible plastic tube running from the kidney along the ureter into the bladder. It is entirely internal. A ureteric stent may be placed for several reasons:

  1. The ureter may be too small to allow easy telescope passage. If this is the case then leaving a ureteric stent in for two weeks allows the ureter to dilate thus allowing ureteroscopy at a later date.

  2. There are residual stones in the kidney, which require further treatment. The stent allows the kidney to continue to drain easily preventing further episodes of colic and allowing easy re-introduction of the ureteroscope at a second procedure.

  3. The stone has been removed however there is concern that the ureter may swell following surgery. This causes pain identical to renal colic. A stent prevents this. The stent is usually removed within two weeks.

Post-procedure

Flank pain is common immediately following ureteroscopy. You may head home later the same day if you are comfortable, otherwise an overnight stay may be recommended. If a ureteric stent has been placed then arrangements will be made to remove this in my office in 1 to 2 weeks’ time. This will be either by a brief flexible cystoscopy or by slowly pulling on a long thread attached to the lower end of the stent.

Risks

Inability to pass the ureteroscope into the ureter: usually due to a tight ureter and dealt with by placement of a temporary ureteric stent then returning for a repeat procedure in two to four weeks.

Incomplete removal of stones: large and multiple stones may require several procedures to clear all stones.

Damage to the ureter: minor damage to the ureter can occur due to trauma from telescope passage. Temporary ureteric stent placement will allow the ureter to heal. The most significant injury is complete ureteric rupture. This is an extremely rare injury. Repair requires an open operation via an abdominal incision. Removal of the kidney may even be required.

Return to Work

Most patients can return to work within one week of surgery. If a ureteric stent is in place then this may cause flank discomfort, more frequent urgent urination and blood staining of the urine. Sedentary jobs can usually be performed with a stent in place however a more physical job may need to be avoided until the stent has been removed.

Follow-up after surgery

Once the stone has been cleared, a metabolic evaluation may be ordered to investigate for reversible causes of stone formation. The results of stone analysis will be discussed. An x-ray three months following surgery will assess for the presence of residual stone fragments.