Kidney & Ureteral Stone Treatments
Stone size, the number of stones and their location are perhaps the most important factors in deciding the appropriate treatment for a patient with kidney stones. The composition of a stone, if known, can also affect the choice of treatments. Options for surgical treatment of stones include:
- Shock Wave Lithotripsy (ESWL)
- Ureteroscopy (URS)
- Percutaneous nephrolithotomy (PNL)
- Open Surgery
Shock Wave Lithotripsy (ESWL®)
This is the most frequently used procedure for eliminating kidney stones. Shock wave treatment uses a machine called a lithotripter. It works by directing ultrasonic or shock waves, created outside your body ("extracorporeal") through skin and tissue, until they hit the dense kidney stones. The impact causes stress on the stone. Repeated shock waves cause more stress, until the stone eventually crumbles into small pieces. These sand-like particles are easily passed through the urinary tract in the urine. The technology is only effective if the kidney is functioning well and there is no blockage to the passage of stone fragments.
ESWL® is a completely non-invasive form of treatment. In most cases, shock wave lithotripsy is done on an outpatient basis. Recovery time is short and most people can resume normal activities in a few days. However, one ESWL® session by itself may not free the ureter of all stone material, and either a repeat ESWL® session or treatment with another approach may be necessary. ESWL® is not the ideal treatment choice for all patients. Patients who are pregnant, obese, have obstruction past the stone, have abdominal aortic aneurysms, urinary tract infections or uncorrected bleeding disorders should not have ESWL®. In addition, certain factors such as stone size, location and composition may require other alternatives for stone removal.
Because of possible discomfort during the procedure, some anesthesia or some form of sedation is generally needed. ESWL® can be performed under heavy sedation, although general anesthesia has been shown to be associated with a higher success rate. Once the treatment is completed, the small stone particles then pass down the ureter and are eventually urinated away. In certain cases, a stent may need to be placed up the ureter just prior to ESWL to may assist in locating the stone or assist in stone fragment passage following treatment.
Certain types of stone (cystine, calcium oxalate monohydrate) are resistant to ESWL and usually require another treatment. In addition, larger stones (generally greater than 2.5 centimeters) may break into large pieces that can still block the kidney. Stones located in the lower portion of the kidney also have a decreased chance of passage..
While shock wave lithotripsy is considered safe and effective, it can still cause complications. Most patients have blood in their urine for a few days after treatment. Bruising and minor discomfort in the back or abdomen from the shock waves are also common. To reduce the risk of complications, urologists usually tell their patients to avoid aspirin and other drugs that affect blood clotting for several weeks before treatment. Another complication may occur if the shattered stone particles cause discomfort as they pass through the urinary tract. In some cases, the urologist will insert a small tube called a stent through the bladder into the ureter to help the fragments pass.
This treatment involves the use of a very small, fiber-optic instrument called a ureteroscope, which allows access to stones in the ureter or kidney. The ureteroscope allows your urologist to directly visualize the stone by progressing up the ureter via the bladder. No incisions are necessary and general anesthesia is used to keep the patient comfortable during the procedure.
Once the stone is seen through the ureteroscope, a small, basket-like device can be used to grasp smaller stones and remove them. If a stone is too large to remove in one piece, it can be fragmented into smaller pieces. Most commonly this is accomplished with laser energy.
Once the stone has been completely treated, the procedure is done. In many cases, the urologist may choose to place a stent within the ureter, to allow any post-operative swelling or reaction to subside.
Percutaneous nephrolithotomy (PNL)
PNL is the treatment of choice for large stones located within the kidney that cannot be effectively treated with either ESWL® or URS. General anesthesia is required to perform a PNL. The main advantage of this approach compared to traditional open surgery is that only a small incision (about one centimeter) is required in the flank. The urologist then places a guide wire through the incision. The wire is inserted into the kidney under radiographic guidance and directed down the ureter. A passage is then created around the wire using dilators to provide access into the kidney.
An instrument called a nephroscope is then passed into the kidney to visualize the stone. Fragmentation can then be done using an ultrasonic probe or laser. Because the tract allows passage of larger instruments, your urologist can suction out or grasp the stone fragments as they are produced. This results in a higher clearance of stone fragments than with ESWL® or URS.
Once the procedure is complete, a tube is usually left in the flank to drain the kidney for a period of time, from overnight to several days.
A large incision is required in order to expose the kidney or portion of ureter that is involved with the stone. The portion of kidney overlying the stone or the ureteral wall is then surgically cut and the stone removed.
At present, open surgery is used only in extremely rare situations for very complicated cases of stone disease.
What can be expected after treatment for kidney stones?
Recovery times vary depending upon treatment, with the less invasive procedures allowing shorter recovery periods and quicker return to activity.
Shock Wave Lithotripsy (ESWL®)
Patients generally go home the same day as the procedure and are able to resume a normal activity level in two to three days. Fluid intake is encouraged, as larger quantities of urine can help stone fragments to pass. Because the fragments need to pass spontaneously some pain can be anticipated. It is possible that the stone may not have shattered well enough to pass all of the fragments. If so, a repeat ESWL® treatment or other options may be required. If a stent was placed prior to ESWL®, this will need to be removed in your urologist's office within a few weeks. Stents are usually well tolerated by patients but can cause some bladder irritation, frequent urination, and flank discomfort.
Patients normally go home the same day and can resume normal activity in two to three days. As with ESWL®, if your urologist places a stent, it will need to be removed in approximately 1-3 weeks.
Percutaneous nephrolithotomy (PNL): After PNL, patients usually stay overnight in the hospital. Your urologist may choose to have additional X-rays done while you are still in the hospital to determine if any stone fragments are still present. If some remain, your urologist may want to look back into the kidney with a nephroscope to remove them. This secondary procedure usually can be done through the existing tract into the kidney. Once the stones have been removed, the stent coming out of the flank is removed and the patient can be discharged. Normal activity can be resumed after approximately 1-2 weeks. If a stent was placed, it will need to be removed in 1-3 weeks.
Because these procedures are the most invasive and painful, patients often spend up to five to seven days in the hospital. Full recovery may take up to six weeks.
Postoperatively, your urologist will encourage a high fluid intake, to keep the daily volume of urine produced greater than two liters a day. In addition, you may need to undergo additional blood and urine tests to determine specific risk factors for stone formation and help minimize the chance for future stones. Although stone recurrence rates differ with each individual, a good estimate to keep in mind is a 50 percent chance of redeveloping a stone within a five-year period.
Information provided by the American Urological Association.