The management of renal matrix calculi: a single-centre experience over 5 years.

Objective: To define incidence of renal matrix calculi in patients undergoing percutaneous nephrolithotomy (PCNL), and describe its clinical, laboratory and radiological features; we also studied the efficacy of PCNL in managing this rare entity.

Patients And Methods: We retrospectively reviewed the records of 1368 PCNLs performed from April 2003 to March 2008, and identified 17 patients (mean age 44.3 years; 11 women and six men) having matrix calculi. The patients' clinical, laboratory and radiological features were studied, and the perioperative outcome and follow-up data analysed.

Results: Flank pain was commonest mode of presentation (15) followed by recurrent urinary tract infection (five). Pyuria was present in 14 patients and urine culture showed significant growth in 10. A plain X-ray showed a small radio-opaque calculus (10 renal units) and faint laminated calcification (four). Intravenous urography showed a filling defect and non-visualized system in nine and five patients, respectively. Non-contrast computed tomography and magnetic resonance urography diagnosed calculi in two and one patient, respectively, on haemodialysis. PCNL was abandoned initially in four patients due to pyonephrosis. The mean hospital stay was 3.4 days and decrease in haemoglobin was 0.89 g/dL. One patient developed sepsis. Of 11 stones analysed, two were composed entirely of proteins and the remaining nine had crystalline components. At a mean follow-up of 12.6 months, no patients had recurrence of stone.

Conclusions: Matrix calculi occurred in 1.24% of patients undergoing PCNL. Although considered radiolucent, plain X-ray showed a small radio-opaque calculi or faint laminated calcifications in 10 of 17 patients. PCNL rendered patients stone-free with minimum morbidity.