The normal body has two kidneys, in the middle of the back, under the lowest ribs. Ureters drain urine from the kidneys to the bladder. The bladder empties urine from the body through another tube called the urethra.
The urinary tract includes all of these structures kidneys, ureters, bladder, and urethra. Kidney stones start as tiny crystals of minerals that stick together when urine is concentrated. This happens with dehydration. Crystals build into stones as more minerals deposit, similar to how a pearl builds in an oyster.
Most small stones pass out of the body, carried by urine. About 1 in 10 people are affected by kidney stones in their lifetime. Dehydration, family history, and some medical conditions increase the risk of stone formation. Symptoms and problems often begin when urine flow is blocked by a stone. This can lead to severe pain, complicated infection, and blood in the urine. These problem stones are a risk for kidney damage. Many of these stones eventually pass without surgery.
This is called expectant management. It can take days to weeks for some small stones to pass on their own. Stones larger than half a centimeter are more likely to need intervention. Some stones need more than one surgery, especially stones larger than 2 centimeters.
Procedures for managing kidney stones that may be considered, include: cystoscopy, ureteroscopy, stent placement, PCNL ESWL We will discuss each of these in more detail to get a better understanding of how, when, and why they may be used. Most of these procedures are performed using scopes, long instruments with a light and a camera. The surgeon uses different scopes for different functions, to see and operate on places inside the urinary tract.
Cystoscopy is the most basic procedure on the list. The surgeon uses a scope to look inside the urethra and bladder for stones and other problems. When needed, guidewires and dilators are passed through the cystoscope into the ureter. During a ureteroscopy, a thinner scope is used. Once kidney stones are reached, other tools are used to break the stones apart and pull the pieces out. Large stones in the kidney, and high in the ureter can require a more invasive approach. A PCNL procedure is done using a scope, guided through a tube in the back, directly into the kidney.
A guidewire is inserted before surgery using x-ray guidance to map where the tube should be placed during surgery. This may be done in a separate radiology suitor in the operating room just before surgery. In the operating room, dilators are placed over the guidewire to create a passage to the kidney. The surgeon guides a scope through the tube to see the stone. Other tools are used to break the stone apart and to remove the pieces. ESWL is known as lithotripsy [say lith-oh-trip-sy].
This non-invasive procedure is often useful for stones in the kidney. An x-ray device is used to pinpoint the kidney stone location and a water-filled lithotripsy device, is positioned against the skin over the kidney and aimed at the stone. Pulses of shock waves are directed at stones to break them into tiny pieces so they can pass out of the body. These pulses create a tapping noise, and sensation on your back, as hundreds of bursts are used at a time.
Patients can have bruising and soreness in their back from the shock waves. Placement of a temporary stent is often a necessary step before, during or after the procedures we have discussed so far. This thin, straw-like, tube is passed through a cystoscope into the ureter then guided up to the kidney. Stents keep the kidney draining. They are temporary but may be needed for days or weeks. Stents can relieve stone pain, and dilate the ureter to help a stone pass.
Stents are placed while an infection is being treated before a stone can be removed. Stents are also needed while the ureter heals after some procedures. The most appropriate procedures for you depend on the size and location of the stone or stones, the severity of the blockage, and your other medical conditions. Before your surgery, understand which procedures are planned or may become necessary to treat your kidney stone.