Evaluation

Initial evaluation of the patient with presumed renal/ureteral calculus disease was investigated in two different studies. Shokeir & Abdulmaaboud (2000) performed a prospective comparison of nonenhanced helical CT and Doppler ultrasonography. They found that sensitivity and specificity of both techniques was high and very similar. Plain abdominal X-ray was compared to the scout film on a nonenhanced spiral CT in an additional study by Jackman et al. (2000.) They found that X-ray alone had a 48% sensitivity whereas a 17% sensitivity was observed on scout CT scans. Taken together, it is clear that the unenhanced spiral CT scan is the procedure of choice for patients with presumed renal/ureteral calculus disease. The CT allows detection of other abdominal conditions that may be associated with symptoms suggestive of renal/ureteral colic. A CT scout film is not as helpful as a KUB.

Etiology

The contribution of dietary oxalate to urinary oxalate secretion is greater than previously recognized (Holmes et al., 2000.) Unless patients have absorptive hypercalciuria, oxalate stone formers should limit dietary oxalate. Restriction of dietary calcium can lead to increased absorption of oxalate.

There is a clear association of renal stone disease with use of indinavir in HIV-positive patients. Saltel et al. (2000) reported a cumulative incidence of indinavir stone formation of 43% for patients treated 78 weeks, with a mean time to stone formation of 23 weeks. Prevention of stone formation is primarily effected by increasing fluid intake. Medical treatment of cystinuria was reported by Barbey et al. (2000) who suggested that a regular medical program of diuresis and alkalinization markedly decreased cystine stone formation. Maintenance of more than 3 liters of urinary volume per day is critical to prevention of stone formation. Not surprisingly, patients who are not compliant with medical therapy have a higher rate of stone recurrence. For patients with spinal cord injury, there is a high risk of renal stone formation, especially within the first three months of injury. Chen et al. (2000) provided evidence of a 3-8% incidence of stone formation within the first 3 months of spinal cord injury.

ESWL

ESWL is a commonly-applied treatment for renal calculi. A review of 5,769 treatments with the Donrnier MFL 5000 lithotriptor was presented from a single center with multiple treating physicians. Stone-free and success rates were 56% and 77%, respectively. Of the 15 treating urologists at this center, the surgeon with the greatest number of patients treated, and highest mean fluoroscopy time had the highest success rate and lowest re-treatment rate. Treatment of eleven patients with ESWL was reported by Czaplicki et al. (2000) without complications. Hematuria was seen for up to 48 hours and skin ecchymosis was common, but this study suggests that treatment of patients with an underlying coagulopathy can be safely effected.

Appropriate use of ureteral stents after ureteroscopy or ESWL remains somewhat controversial. A prospective study of 44 patients ureteroscoped for removal of a large (0.6 - 1 cm) distal ureteral stone with the Swiss Lithoclast was reported by Rane et al. (2000). Based on the fact that only one patient who was not stented had significant pain postoperatively, routine stenting after ureteroscopy was not recommended. Late complications of ureteral stents were reported by Ringel et al. (2000.) Approximately one-third of patients had late complications including stent fragmentation, migration, persistent hydronephrosis or infection. Complications were seen as early as three months after placement, supporting their early replacement for patients requiring chronic stent maintenance.