Dietary oxalate is plant-derived and may be a component of vegetables, nuts, fruits, and grains. In normal individuals, approximately half of urinary oxalate is derived from the diet and half from endogenous synthesis. The amount of oxalate excreted in urine plays an important role in calcium oxalate stone formation. Large epidemiological cohort studies have demonstrated that urinary oxalate excretion is a continuous variable when indexed to stone risk. Thus, individuals with oxalate excretions >25 mg/day may benefit from a reduction of urinary oxalate output. The 24-h urine assessment may miss periods of transient surges in urinary oxalate excretion, which may promote stone growth and is a limitation of this analysis. In this review we describe the impact of dietary oxalate and its contribution to stone growth. To limit calcium oxalate stone growth, we advocate that patients maintain appropriate hydration, avoid oxalate-rich foods, and consume an adequate amount of calcium.

At long-term follow-up, PD is not a durable material in sling surgery. Although QOL generally improves after surgery, most SUI recurrences occurred soon after surgery.

Introduction Percutaneous nephrolithotomy (PCNL) has potential for morbidity or failure. There are limited data regarding risk factors for failure and no published reports of surgical outcomes among patients with prior failed attempts at percutaneous stone removal. Methods Patients referred to three medical centers after prior failed attempts at PCNL were identified. Retrospective chart review was performed analyzing reasons for initial failure and outcomes of salvage PCNL. Outcomes were compared to a prospectively maintained database of over 1200 patients undergoing primary procedures. Results Thirty-one patients underwent salvage PCNL. Unsuitable access to the stone was the leading reason for failure (80%). Other reasons included infection, bleeding, and inadequate instrument availability (6.5% each). Compared to patients undergoing primary PCNL, those undergoing salvage were more likely to have staghorn calculi (61.3% vs. 31.4%, p<0.01), larger maximum stone diameter (3.7 cm vs. 2.5 cm, P<0.01), and require secondary procedures (65.5% vs. 42.1%, p<0.01). There was no significant difference between cohorts for the remainder of demographics or perioperative outcomes. All patients were deemed completely stone free except one who elected to observe a 3 mm non-obstructing fragment. Conclusions Despite the more challenging nature and prior unsuccessful attempts at treatment, outcomes of salvage PCNL were nearly similar to primary PCNL.

Our results suggest that some degree of oxalate secretion in the small intestine may occur in the fasted state while this is less likely in the stomach. Further studies are warranted to provide definitive evidence of gastrointestinal secretion of oxalate.

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