Metabolic investigation of patients with staghorn calculus: is it necessary?

Objective: To evaluate the prevalence of metabolic disorders in patients with staghorn calculi treated at the Regional Center of Lithiasis Metabolic Studies in central region of São Paulo State, Brazil. Materials and methods: Between February 2000 and February 2008, 630 patients with urinary calculi were evaluated in the lithiasis outpatient clinic. Thirty-seven of them had staghorn calculi (35 women and 2 men). The inclusion criteria for the metabolic investigation included the absence of urological manipulation 30 days before the examination, negative urine culture and creatinine clearance > 60 mL/min. The protocol for metabolic investigation consisted of qualitative search for cystinuria. Two non-consecutive 24-hour urine samples collected to measure calcium, phosphorus, uric acid, sodium, potassium, magnesium, oxalate and citrate, and serum calcium levels , phosphorus, uric acid, sodium, potassium, magnesium, chloride, parathormone and urine pH. Results: Among patients with lithiasis, 5.9 percent (37/ 630) had staghorn calculus and in 48.6 percent (18/37) were diagnosed with urinary infection. The females were predominant for 94.5 percent of cases. The calculi were unilateral in 31 of cases and bilateral in six. Metabolic abnormalities were found in 68.2 percent of patients with hypercalciuria (64.2 percent) and hypocitraturia (53.3 percent) being the most common disorders. Conclusions: The presence of metabolic disorders in nearly 70 percent of patients with staghorn calculus reinforces the necessity for evaluation of these patients. The diagnosis and treatment of identified metabolic abnormalities can contribute to the prevention of recurrent staghorn calculi.

Retroperitoneoscopic renal biopsy in children

OBJECTIVE: We present our experience in a series of 17 consecutive pediatric patients submitted to retroperitoneal laparoscopic renal biopsy. MATERIALS AND METHODS: Retroperitoneal laparoscopic renal biopsy (LRB) was performed in 5 boys and 12 girls. Mean age was 8.1 years and age range from 2 to 12. Two or three trocars were used to expose the inferior pole of the kidney, remove enough cortical parenchymal specimen and fulgurate the biopsy site. Assessment included surgical time, estimated blood loss, hospitalization period, analgesia requirements, complications and number of glomeruli present in the specimen. RESULTS: LRB was successfully performed in all 15 patients (88 percent). In two cases, LRB was not possible to be performed. One patient was converted to a transperitoneal laparoscopy due to tear in the peritoneum. The other patient had had previous abdominal surgery and, during retroperitoneal balloon dilation, the peritoneum was opened and the open biopsy was performed. A third patient had postoperatively a perirenal hematoma, which was solved spontaneously. Complication rate was 17.6 percent (3/17 cases). Mean operative time was 65 minutes, while mean estimated blood loss was 52 mL, mean hospital stay was 2.2 days and mean analgesic requirement was 100 mg of tramadol. The mean number of glomeruli present in the specimen was 60. CONCLUSION: Retroperitoneal laparoscopic renal biopsy in children is a simple, safe. Bleeding is still the most common complication. However, direct vision usually allows a safe control of this drawback. In our institution, laparoscopic approach is the chosen procedure in pediatric patients older than one - year - old.