Removing Kidney Stones

Kidney stones are hard deposits of salts and minerals that form inside the kidney. Approximately 1 in 10 people will develop a kidney stone in their lifetime. In our latest medical article, leading consultant urologist and urological surgeon Mr Vimoshan Arumuham discusses the different methods of kidney stone removals that are available to patients. He explains what the procedures entail and for what type of stone they are most suitable. 

How do you remove kidney stones?

You may be thinking of kidney stone removal if you have developed pains in your back and a stone has been found, if you have been getting recurrent urinary tract infections or even if you have been seeing blood in the urine. The most painful presentation of kidney stones is when they drop into the ureter, causing “ureteric colic”. This is a medical emergency which requires some form of scan, most likely a CT, and a discussion with a medical professional as to the best approach to treat it. However, when kidney stones are in the kidney, there are 4 different ways they can be removed: 

Extra Corporeal Shockwave Lithotripsy (ESWL)

The first, and least invasive method is called Extra Corporeal Shockwave Lithotripsy (ESWL). It uses high frequency sound waves targeted at the stone to break it down into tiny fragments. It is then up to body to pass these from the kidney into the urinary channels and out of the body. It is often the most preferred treatment by most people since it is truly minimally invasive. It takes roughly between 30 and 40 minute to perform and is done whilst the patient is awake and is often a clinic-based treatment. I often describe it to patients as a rubber band “flicking the skin”.

However not everyone is a suitable candidate for this procedure. It works best on smaller (often less than 1cm), softer stones, stones that are in favourable positions and where the skin to stone distance is not too large. You cannot have this treatment if you are taking medication to thin your blood (due to the risk of bleeding), if you have an aneurysm (so called swelling of the blood vessels in your abdomen) or pregnant. 

As the stones pass there is roughly a 1 in 10 chance that they may get stuck in the ureter which is the tube that connects the kidney to the bladder. This is obviously more likely the greater the size of fragment and, by inference, the larger the stone that is being treated).

ESWL can work in stones in the kidney, and in some cases stones right at the top of the ureter where they start to make a bid for freedom, or right at the bottom of the ureter just before they enter into the bladder. It will not work in the rest of the tube which lies too deep inside the body and the trapped stone cannot be visualised. 

The second and third approaches are more invasive and involve a general anaesthetic. 

Flexible Ureterorenoscopy (and Laser Fragmentation)

The second approach is called a flexible ureterorenoscopy (and laser fragmentation). This involves a tiny flexible camera that is passed through your water pipe (urethra) into the ureter (the tube connecting your kidney to your bladder) and into your kidney. A small laser fibre is used to fragment the kidney stone into tiny sub-millimetre fragments, which are then extracted systematically. After the procedure you are likely to be left with an ureteric stent – which allows any tiny fragments to pass by themselves and also allows the ureter to heal after the operation. 

Unfortunately, despite the stent allowing the kidney to heal, the body does realise that it is a foreign object and reacts in the form of “irritative” urinary symptoms. These often include, but are not limited to; Urgency and frequency of urination, burning when passing urine, blood and pain in the back. These symptoms are very similar to those of a urinary tract infection. Around 3 in 5 people will experience varying degrees of these symptoms but it is very difficult to predict who and to what intensity before the operation itself. Thankfully, the side effects of a stent are temporary and will inevitably resolve upon removal. 

Therefore, the second option to treat kidney stones will often come as a package: The first part involves treating stones under General Anaesthetic (This often is a day-case procedure, which can around an hour to an hour and a half to perform) and the second part is the removal of the ureteric stent under local anaesthetic.

Picture of an Ureteric Stent

Percutaneous Nephrolithotomy

The third option, is often reserved for patients with a substantially larger stone burden (usually greater than 2cm worth of stone) or with anatomy considerations which make it very difficult to access their ureter from below. It is called “Percutaneous Nephrolithotomy” and involves a small (roughly 1cm) cut in the back over where the kidney lies. A needle is introduced into the kidney with the aid of ultrasound and X-rays, which is then used to dilate to a tract that will allow passage of a small rigid camera that will reach the stone. We can treat larger stones as the instruments are larger - this is usually with the use of a larger laser fibre or with the aid of a pneumatic drill and suction device which can clear stone rapidly. Due to its more invasive nature (and although the returns are greater), the procedure has a higher and more serious risk profile. 

Dissolution treatment

Finally, although there are 5 major types of kidney stones, only 1 type (Uric Acid) can be removed by the 4th approach which is called “dissolution treatment”. This is effectively when the patient takes medication to dissolve the stone. Uric acid stones form in acidic conditions and can be heavily influenced by diet. The combination of increasing one’s fluid intake (which is an essential treatment strategy for every stone former), altering diet to reduce the consumption of “purine” and the addition of medication taken either syrup or tablet form (daily) can increase the pH of the Urine and thus dissolve out. I have utilised such methods to clear stones the size up to 3cm - but is heavily dependent on the patient’s drive to adhere to treatment.

If you are concerned about symptoms of a kidney stone, you can book a consultation with Mr Vimoshan Arumuham by visiting his Top Doctors profile.