Extracorporeal Shock Wave Lithotripsy (ESWL) may be used to fragment stones that are in the kidney or in certain parts of the ureter. The success rate of breakage depends on the size of the stone, the location within the kidney or ureter, the composition or make-up of your particular stone, and the number and energy level of the shocks employed. The second part of success is whether or not the fragments pass out of your system.
This will depend on the original location of the stone, the size of the fragments, and on the particular anatomy of your urinary tract.
The procedure involves the application of high-energy shock waves to stone(s) within the kidney, produced from a machine (lithotriptor) positioned outside the body. Therefore, no skin cuts are required. This is NOT a form of laser technology. Lasers are only used to fragment stones with the minimally invasive procedures in which scopes are inserted into the urinary system.
Please refer to the detailed information provided by the rooms. A urine culture will be obtained before the procedure. Any urinary tract infection must be cleared before the procedure can take place. It is necessary, as with any procedure or operation requiring anesthesia, that you have not eaten for at least 6 hours prior to the scheduled time. In order to assist us with visualising your stone, we may ask you to clean out your intestines and colon the night before. You should plan a very light dinner (perhaps around 5-6:00pm) the evening prior and avoid vegetables or other foods that typically cause gas.
A plain X-Ray may be requested on the day of the procedure just to be sure that the stone has not moved.
* Patients who are being treated for abnormal heart rhythms (ie. atrial fibrillation or patients with pacemakers) can have this procedure, but it is important that we know so that we may communicate with your cardiologist and possibly make special preparations with the ESWL machine and with the anesthesiologist.
You will be placed lying on your back and the stone will be localised with real time x-rays (fluoroscopy) and/or ultrasound technology. Some machines necessitate that you be partially submerged in a water bath and others do not. Once we are satisfied that your stone can be accurately targeted with the shock waves, you will be given general anesthesia. Shock waves are aimed precisely at the stone. The maximum energy level used and the number of shocks administered will depend on how your stone responds to the shocks. There is, however, a maximum level at which point we will terminate the procedure. At the end of the procedure, we often have an idea as to its success. However, a stone that appears well fragmented during the procedure can often be found to be unchanged on the follow-up x-rays weeks later. Alternatively, a stone that appeared unchanged during the procedure is sometimes not seen at all on follow-up x-rays due to successful fragmentation and passage.
After the procedure, you will be in the recovery room until you are ready to be discharged. It is uncommon for a patient to be admitted to the hospital afterward, but certain circumstances could make admission necessary.
It is common and even expected to have some discomfort in your back on the treated side. Over the next day or two, your urine may appear dark or amber which represents the presence of blood. You may have no blood in the urine, mild blood, or even what appears to be a significant amount of blood or small clots. It is rare for the blood to not disappear within a day or two. You may also notice stone fragments passing in the urine, and this is the desired result. Because they are small, a patient typically does not feel them as they pass in the urine but they can be visible as sand or very small pebbles.
Approximately 4 weeks after the procedure you will have a plain X-ray to determine how well the stone(s) have fragmented.
Expectations of Outcome
The intent of ESWL is to completely fragment the stone and have all pieces pass out in the urine. Unfortunately, this is not always the case. Sometimes, the stone does not break at all, or there is incomplete fragmentation and only part of the stone breaks. In this regard, we may suggest another ESWL at a later date. Sometimes the stone fragments quite well, but the pieces never leave the kidney. This is most common with stones that are in the lower half of the kidney. The combination of the sharp angle and gravity holding them in the lower half, make it less likely that they move into the ureter.
Occasionally, and more common to larger stones, a large fragment can get caught in the ureter and temporarily block the kidney. In this situation, we may elect to observe (if you are comfortable and the fragment is of a size that may permit spontaneous passage) or we may recommend placement of a stent. Sometimes, a stent will be placed during the procedure, especially if a large stone is being treated. This is in order to prevent ureteric obstruction and pain caused by large fragments passing down the ureter. If necessary, we might recommend a ureteroscopy procedure (putting a small telescope into the ureter) to further fragment and/or remove the large piece.
Possible Complications of the Procedure
The vast majority of patients will not experience any problem after ESWL. However, any procedure, regardless of complexity or time, can be associated with unforeseen problems. They may be immediate or even quite delayed in presentation. These may include, but are not limited to:
- Urinary Tract Infection or Urosepsis
Although we may give you antibiotics, it is still possible for you to get an infection. It may be a simple bladder infection that presents with symptoms of burning urination, urinary frequency and a strong urge to urinate. This will usually resolve with a few days of antibiotics.
Pyelonephritis (kidney infection) is also possible following ESWL and is more likely to cause symptoms of severe back pain, fevers, chills, nausea, and vomiting. If the infection enters the bloodstream, you might feel very ill as well. This type of infection can present with both urinary symptoms and any combination of the following: fevers, shaking chills, weakness or dizziness, nausea and vomiting. You may require a short hospitalisation for intravenous antibiotics, fluids, and observation. This problem is more common in diabetics, patients on long-term steroids, or in patients with disorders of the immune system.
*If you have symptoms suggesting any of the above after your discharge from the hospital, you must contact us immediately or go to the nearest casualty.
- Ureteral Blood Clots
Rarely, small blood vessels in the kidney can rupture and cause bleeding in the urine. If clots form, they can block the urine flow down the ureter. Treatment is usually observation or placement of a stent.
Occasionally, small blood vessels can rupture and cause significant bleeding around the kidney (haematoma). The majority of the time, the treatment is observation because the bleeding stops itself and is eventually reabsorbed by surrounding tissue. In some circumstances, a minimally invasive procedure (angiography) is done by special radiologist physicians to stop the blood vessel. A need for open surgery with possible removal of the kidney (nephrectomy) due to bleeding is extremely unusual.
- Loss of Kidney Function
There is bruising to the kidney from this procedure. Like other organs in the body, the kidney heals itself with time. It is possible, although very unlikely for a part or even the entire kidney to lose function following ESWL. This can result from the shocks to the kidney or from local or diffuse bleeding.
Please follow the instructions given to you by the hospital regarding when you should make an appointment to see Dr Sved. You may see him in his offices at RPA, Bankstown or Strathfield Private Hospital. Do not hesitate to call our office at any time if you have any concerns.