Bilateral urinary calculi with discordant stone composition.

OBJECTIVES: To describe a cohort of bilateral stone formers with significantly different compositions between renal units. METHODS: Patients treated for bilateral nephrolithiasis over a 4-year period (2007-2010) were identified. Stones were categorized by dominant (≥50%) mineralogical component. Patients with significant compositional differences between renal units (discordant stone formers) were compared to patients with a similar stone type in each kidney. RESULTS: Fifteen of the 59 bilateral stone formers (25.4%) were discordant stone formers with significant differences in stone composition between renal units. Forty-four of the 59 patients (74.6%) had the same stone composition on each side. Thirty percent of discordant stones had calcium phosphate as the dominant stone component. Discordant stone formers were younger, had better renal function, and tended to have a larger stone burden (p < 0.05). CONCLUSIONS: A significant minority of bilateral stone formers form a different type of stone in each kidney. Local or micro-environmental etiologies may explain this phenomenon and may also account for failure of preventive therapy in some patients.

The FECal Double-J: a simplified approach in the management of encrusted and retained ureteral stents.

INTRODUCTION: The management of the forgotten, encrusted, calcified (FECal) Double-J ureteral stents can represent one of the most difficult and challenging surgical conditions for the practicing urologist. We present a novel and simple grading system for the FECal stent and, taking into account our own experience and literature review, propose an algorithm in the management of the encrusted stent based on this new system. MATERIALS AND METHODS: A retrospective analysis of our stone database was performed from March 2000 to April 2007 revealing a total of nine patients presented with a FECal Double-J stent managed at our institution and included in our series for further analysis. Based on this population, our experience, and current surgical techniques, we designed a simplified grading system to universally define the retained indwelling FECal ureteral stents. RESULTS: A total of nine patients with encrusted and retained ureteral stents were identified, graded, classified, and treated at our institution. Our population consisted of five women and four men with an average age of 54.4 years and average stent indwelling time of 11.44 months. We present our novel management algorithm based on our simplified FECal stent grading system. CONCLUSION: The management of the FECal ureteral stent represents a formidable challenge due to the need for a multimodal approach with advanced endourological techniques. Our proposed grading system and management algorithm provide a simplified and directed alternative for the surgical management dilemma of the encrusted retained ureteral stent.