Endoscopic removal of kidney stones is a process in which the doctors can remove one or more kidney stones using an endoscope (a tube containing a small camera, a light and a device to break up the stone). The process is also called percutaneous nephrolithotomy (PCNL).
The process is carried out by a urologist (doctor specializing in the urinary system) and a radiologist (doctor specializing in imaging techniques). The procedure usually takes about 2 to 3 hours.
Kidney (or renal) stones are batch of tiny crystals that can form in the kidneys. Most batches are too small to cause any problems and pass out of the body in the urine.
At times, the clusters can clump together to form bigger clusters, which may eventually become big enough to block the urine collecting system in the kidney.
At times, the stones pass out from the kidney down the ureter in the urine without causing any problems, but if they are big they may block the ureter or get stuck in the bladder.
Some kidney stones do not cause any symptoms at all, particularly if they are very small and are not causing a blockage.
However, kidney stones can be painful and cause blood in the urine (haematuria) and general feelings of being unwell, such as a high temperature and vomiting. If the stone passes out of the kidney into the ureter, it can cause severe pain.
Kidney stones can cause an infection. Signs of an infection include a high temperature, vomiting or diarrhea and urine that are pink or cloudy.
What does the procedure involve?
Endoscopic removal of kidney stones is always carried out while the patient is under a general anesthesia because they need to lie very still throughout the procedure and it can take a while.
It is important that the patient does not eat or drink anything for a few hours before the anesthesia. This is called ‘fasting’ or ‘nil by mouth’. Fasting reduces the risk of stomach contents entering the lungs during and after the procedure.
The patient will be informed the night before the procedure of the time that he should be ‘nil by mouth’ – in other words, have nothing to eat or drink before the anesthesia. Fasting timings are provided in the admissions form – in broad terms, which is 6 hours for food (including milk), 4 hours for breastfeeding and 2 hours for clear fluids before the procedure.
Once the patient is under general anesthesia, the doctors will insert the endoscope into his urethra. From here, the doctors will pass it into the bladder. Using the endoscope, the doctors will insert a soft plastic tube into the patient’s ureter towards the kidney.
A second small plastic tube is placed alongside this tube into the bladder (catheter). The tube in the ureter is removed at the end of the procedure, while the bladder catheter will be removed from the ward a day or two after the operation.
The patient will be rolled over onto their tummy and an ultrasound scan will be used to identify the kidney and the best way to reach the stone(s) inside it.
A soft guide wire is threaded through the needle, which is then removed. The position of the guide wire is checked using an X-ray. The tract through the skin, muscle and fat to the kidney (around the guide wire) can then be stretched until it is wide enough to take the tube containing the camera (endoscope).
Once the doctors can see the stones on the camera, they can remove them using the endoscope if they are small enough. Larger stones can be broken up using an ultrasound or laser device inside the endoscope. If there is more than one kidney stone, the doctor may need to create further tracts through the skin to reach the stones.
Once the doctors have removed as many of the kidney stones as possible, they will leave a nephrostomy through the tract created during the procedure.
This is a thin, plastic tube that comes out through the skin to drain urine from a kidney. This is stitched in place and a dressing is used to cover it.
Urine and any small bits of kidney stone drain from the kidney through the tube into a bag which needs to be emptied regularly in the ward. Most children have some blood in the urine and fluid leak alongside the nephrostomy for the first few days after the procedure.
The stones removed from the kidney are sent to the laboratory to help understand why they have formed.