Kidney Stones: Better to Crush, Capture, or Write a Prescription?

Are there any effective medical options for treating urolithiasis?

Medical technology is a double-edged sword. CT scans help detect early disease, but with the addition of contrast, they may cause renal failure. Pacemakers save countless lives, but they can become infected and lead to serious complications.

"High-tech" modalities--for example, cardiac catheterization, coronary artery interventions, and vascular coils--have reduced morbidity and mortality associated with debilitating or fatal diseases, such as myocardial infarction and subarachnoid hemorrhage. However, as a result of the widely publicized success of these and other technological advances, many "lower-tech" (and thus less costly) therapies may have been overlooked.

THE "HIGH-TECH" APPROACH TO KIDNEY STONES
Two commonly used "technological" therapies for ureteral stones are lithotripsy and ureteroscopy. They are neither inexpensive nor completely safe. Average charges for lithotripsy total $4225. Of those treated, 15% to 32% experience a perirenal fluid collection or a subcapsular hemorrhage as a result. In some trials, 50% of patients who underwent lithotripsy required a second treatment. Ureteroscopy costs $2645 on average and has an overall complication rate of 10% to 20%. Three to five percent of the procedures cause major complications (eg, ureteral avulsion).¹

In 2000, inpatient and outpatient claims for ureteral lithiasis totaled $2 billion in the United States. If a noninvasive therapy is as safe or safer, is at least as effective in facilitating stone passage, and is less expensive than lithotripsy and ureteroscopy, it should be given a chance.

A MEDICAL ALTERNATIVE
A recent meta-analysis pooled data on medical treatment of ureteral stones ("expulsive therapy") with calcium channel blockers (9 trials, 3 with the addition of a corticosteroid) and/or an α-blocker (4 trials) in nearly 700 patients.¹ Theoretically, calcium channel blockers directly relax "colicky" smooth muscle in the distal ureter and help expel the stone. In the same setting, α-blockers work as they do in benign prostatic hypertrophy, causing muscle relaxation through their effect on α-adrenergic innervation to the ureter. Corticosteroids decrease inflammation in an injured and irritated ureter.

When the medications were used as the sole therapy, the passage rates were impressive. Calcium channel blockers or α-blockers made it 65% more likely that a patient would pass the stone. Use of an α-blocker alone (eg, tamsulosin) made it 1.5 times as likely that a stone would be passed; with a calcium channel blocker alone, the benefit was nearly the same. Adding a corticosteroid to a calcium channel blocker made it 1.9 times more likely that a stone would pass, compared with placebo.

Costs for medical therapy ranged from $10.74, for a 28-day course of doxazosin, to $104.41, for a 42-day course of tamsulosin. In addition, medical treatment reduced both emergency department visits as well as days taken off work. Side effects (eg, low blood pressure and palpitations) were few.

The authors were frank about the potential drawbacks of their results. Since most published studies are positive (ie, if the medical treatment is ineffective, the trial results are less likely to be reported in the literature), there may be a publication bias. Also, medical therapy targets only stones smaller than 1 cm (in the studies included in the meta-analysis, the largest mean stone size was 7.8 mm) that are in the distal ureter. Nonetheless, in an accompanying editorial, Dr Margaret Pearle wrote, "Patients with ureteral stones measuring less than 1 cm who are candidates for observation [eg, those who do not have an infection], especially those with stones in the distal ureter, deserve a trial of medical expulsive therapy."²