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Extracorporeal Shock Wave Lithotripsy (ESWL)
A common surgical treatment of kidney stones is ESWL (Extracorporeal Shock Wave Lithotripsy). ESWL involves a special machine that can direct ultrasonic energy toward the stone without placing any instruments inside the body. The stone(s) are fragmented into tiny pieces to allow them to pass down the ureter and into the bladder more easily. No instrumentation of your urinary tract is usually necessary. When treating very large stones with ESWL you may need a plastic tube in the ureter. This tube is called a ureteral stent and protects the ureter and kidney while the ureter is healing. Generally, this stent remains in place for seven or more days.
There is a lot of uncertainty with renal stone management. Many factors impact the outcome of any management course you elect to take. You could choose to do nothing. Stones up to 10 mm (1cm) can pass on their own. Roughly, the chance of a stone passing spontaneously is inversely related to the stone size in millimeters. A 1mm stone passes 90% of the time, a 5 mm stone 50% of the time, a 9 mm stone 10% of the time and so on. The chance of passing stone fragments (including fragments remaining after a successful stone therapy) also depends on the kidney and ureter anatomy that you were born with. A dilated ureter after stent removal (a ureteral stent can cause the ureter to widen or dilate over time) is usually more able to accommodate larger stone fragments.
Any of the common stone therapies, Extracorporeal Shock Wave Lithotripsy (ESWL), ureteroscopy (URS), and Percutaneous Nephrolithotomy (PCNL) will leave behind some stone fragments that the patient must pass post-operatively. It is not uncommon to have to return to the operating room a second or third time to remove all the stone fragments. However, in most cases, stones can be successfully eradicated with one trip to the operating room.
ESWL is least likely to make you stone-free in one trip to the operating room and usually does not require any stents or tubes. ESWL is most appropriate for small stones in the kidney or upper ureter. ESWL involves a special machine that can direct ultrasonic energy toward the stone without placing any instruments inside the body. The key to successful ESWL is being able to accurately focus the shock wave energy at the stone. For this reason, stones less than 5mm size, stones that are not visible on plain x-rays, and stones hidden by the pelvic bones (lower ureteral stones) are difficult to treat with ESWL.
Of these three stone therapies (ESWL, URS, and PCNL) PCNL is the most aggressive and has the greatest chance of making you stone-free with one trip to the operating room. It is the treatment of choice for large complex stones in the kidney. This treatment requires a tube through your back into your kidney called a nephrostomy tube. In most cases the nephrostomy tube can be converted to an internal ureteral stent (a plastic tube positioned in the kidney, ureter and bladder). This may be done at the time of PCNL or sometime after surgery by a radiologist. Usually after the internal stent is placed the nephrostomy tube can be removed. PCNL usually requires 1-5 days in the hospital.
Some large stones treated with ESWL will require stent placement. Routine ESWL can be performed as an outpatient surgery.
URS (ureteroscopy) is the most versatile form of stone therapy. URS involves placing a small telescopy (ureteroscope) into the tube that connects the kidney to the bladder (the ureter).Virtually any stone can be reached using URS. Special laser fibers can be deployed through the utereroscope to fragment the stone. Special baskets can be deployed through the ureteroscope to retrieve any stone fragments. URS is usually the technology of choice for stones in the ureter, especially the lower ureter. Large renal stones can be treated with URS, ESWL, and/or PCNL. Some complex stones may require a combination of two or more treatment modalities. Routine URS can be performed as an outpatient surgery.
In some cases cystoscopy and placement of a ureteral stent can be used as treatment of a kidney stone. The stent dilates the ureter and makes the ureter wider (temporarily) and therefore, more likely to allow stone passage. Sometimes the stone or stone fragments are passed when the stent is removed and sometimes stone passage occurs a short time after stent removal. Commonly, stent placement is used during an acute stone episode to relieve obstruction of the ureter. In these cases URS, ESWL, or PCNL may be scheduled electively after stent placement.
If your treatment required stent placement you may be given Ditropan (oxybutynin) 5mg tablets or some other anticholinergic medication. Initially with Ditropan (the first day or two after the procedure) you should take 1 tablet every 6-8 hours. 1-2 days after the procedure you can simply take the tablets when you feel that you need it (when you are having bladder spasms). In time many patients stop having bladder spasms and can stop taking this medication.
ESWL post-op instructions:
Problems you should report to us:
You will also have some burning with urination. This is normal after stone therapy and is also expected while the stent is in place. This burning should be mild or moderate and should improve over time. Severe burning, especially when it is not improving, can be a sign of infection.
If you have a stent, you will need a follow-up appointment to remove your stent. Call for this appointment at (302) 571-8958. Stent removal is easy when the string is left attached to the stent (our usual procedure) with the string emanating from the urethra. You will lie down on an exam table so we can use the string to pull the stent out. This procedure takes just seconds and feels funny but does not usually cause pain. In some select cases it is important to not leave the string on the stent. In these cases you will not see the string coming out of the urethra. Also, in these cases it will be necessary to remove the stent with cystoscopy (usually in the operating under IV sedation). The stent is usually removed 1-2 weeks after treatment.