URETEROSCOPY & LASER
If you have a stone blocking the flow of urine from your kidney you will have been scheduled for surgery to relieve this blockage. You may have had a stent (a long thin plastic tube passing from the kidney to the bladder to bypass the stone and unblock the kidney) placed already. Dr Ende may have organised an X-ray to be taken at the time that you are admitted to Hospital to check on the position of the stone. Unless the stone is very small it is very uncommon for it to have passed while the tube is in place.
During the procedure the stent, if present, will be removed. A long fine telescope will then be passed through the penis and up to where the stone is lying in the ureter or in the kidney. A laser fibre will be passed through the telescope and the stone will be vapourised. If possible the fragments will be removed, but often if they are small enough they will pass quite freely without causing any problems.
On some occasions it may be necessary to place a stent back into the kidney following the procedure. This will only be performed to protect the kidney if there is a risk of pain or infection. In this situation the stent will only be needed for a short time (and in some circumstances a string may be left attached to the end of the stent which can then be removed quite easily either in Casualty or in Dr Ende’s rooms). There is a small risk of bleeding and infection during the procedure. It is extremely rare for any significant injury to the kidney to occur. In almost all cases the patient will go home on the same day as the procedure.
As mentioned above, some stones may be amenable to dissolution therapy. If the stone is thought to be composed of uric acid, it can often be dissolved using simple sodium bicarb. This will not help in the situation of an acute blockage with pain as it can take several weeks for a stone to dissolve. It is useful for uric acid stones identified in the kidney that are not causing symptoms as they can be treated over time.
Kidney stones are commonly identified when CT scans or X-rays are performed of the abdomen. Stones found in the kidney often are completely asymptomatic and patients will not have been aware that stones were present. Patients may have had stones in the past, which is associated with a higher risk of further stones forming, but unless they cause symptoms such as pain, bleeding or infection, patients will be unaware of their presence. When stones are found in the kidney as an incidental finding an easy method of treatment is shock wave therapy, called lithotripsy. This usually involves the patient having a general anaesthetic and a shock wave generator is then aimed at the kidney stone using either X-ray or ultrasound to localise the stone. Shock waves of increasing intensity are then generated to fracture the stone into tiny fragments that will then pass out in the urine, often without the patient being aware. The procedure is extremely well tolerated with very few complications. The patient usually experiences some blood in the urine for a short time and may feel an ache in the back for a day or two. The patient may even see a small bruise on the skin where the shock waves have passed through the body into the kidney.
The clearance of a kidney stone depends on its size and location within the kidney. Very hard stones may not fracture as easily as softer stones and stones in the lower part of the kidney generally do not clear as well as those from the top half of the kidney. In general this is a very effective way of treating kidney stones but may not be as accurate as direct visualisation with telescopes and vaporization with lasers.
Very large stones are occasionally identified in the kidney and sometimes even large stones may be asymptomatic. Stones larger than 3cm or 4cm are usually best treated by a direct puncture into the kidney with subsequent creation of a track to pass a telescope directly onto the stone.
Laser treatment for such large stones is possible although the procedure can be very prolonged and shock wave treatment for such large stones will often leave significant sized fragments requiring repeat treatments.
When a track is made through the skin directly into the kidney an instrument can be passed through the telescope that fractures the stone and sucks out all the fragments at the same time. In most cases the stone can be completely cleared in a single sitting. Of course this procedure is a little more invasive than the other stone treatments but for large stones it is often the best way for complete clearance in a single treatment.