Treatment for kidney and ureteral stones is chosen based on 3 criteria: the location, size, and type of kidney stone. Most kidney stones present with symptoms when they fall into the ureter (the tube that connects the kidney to the bladder). If the stone size is less than 6 mm, almost 80% of these stones in the ureter will pass by themselves. As such, one needs to take only pain medication to relieve the symptoms until the stone passes. If there are any signs of infection or if the patient is unable to perform regular daily activities, it may be reasonable to proceed with treatment for ureteral stones, even if they are less than 6 mm in maximal length.
Stones that are larger than 6 mm usually do not pass by themselves and need either extracorporeal shockwave lithotripsy (SWL) or ureteroscopy and holmium laser lithotripsy for stone fragmentation and removal. Stones that are in the proximal ureter are good candidates for SWL, whereas stones in the mid and distal ureter are best treated with ureteroscopy and laser lithotripsy. Stones up to 2.5 cm in the kidney may be treated with SWL. Stones larger than 2.5 cm are best treated with percutaneous surgery. Stones located in the lower portion of the kidney and larger than 2 cm are also best treated by percutaneous surgery rather than SWL.
The stone type also impacts on the selection of therapy. Uric acid stones, which are very common in Colorado, are best treated with dissolution therapy (oral medications). Usually, an alkali such as potassium citrate is necessary to dissolve the stone. Most patients with uric acid stones do not need SWL nor endoscopic surgery. However, if the stone is larger than 6 mm and is composed of either calcium oxalate, calcium phosphate, cystine, or struvite (infection stones) either SWL or endoscopic surgery will be necessary. The choice of specific stone treatments is ultimately made based upon a trade off between invasiveness of surgery versus treatment effectiveness, with the patient being an active participant in the decision process.
Despite the advent of lithotripsy for the treatment of kidney stones, greater than 90% of patients with recurrent stones want to prevent future stones. As the pain of passing a ureteral stone is one of the most intense and disabling pain experienced, most patients are willing to follow a fluid, dietary, and/or pharmacological therapy to prevent future episodes. Not only from the patient’s perspective but also from a cost-effectiveness standpoint, prevention of kidney stones is superior than simply treating the stone when it reoccurs. Depending upon the stone type, a multitude of metabolic abnormalities may lead to the development of kidney stones. For calcium oxalate stones, either too much calcium, oxalate, uric acid, or too little citrate in the urine can lead to stone recurrence. Dietary factors are often responsible for these abnormalities and may be readily corrected to prevent stones.
Depending on a particular patient and stone type, either a Limited or a Comprehensive Metabolic Evaluation is necessary to evaluate and plan therapy for stone prevention. As a minimum, a 24-hour urine sample should be first analyzed to determine the cause of stone formation. The advantage of the Comprehensive Evaluation over a Limited Evaluation is that the precise reason for stone formation is better defined and more options of therapy, either dietary or pharmacological, are available for the patient to choose based on their lifestyle. Typically the patient needs be followed once or twice a year, based on their history of stone disease severity, to prevent future stones.
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