Dietary oxalate and kidney stone formation.

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.

Salvage Percutaneous Nephrolithotomy: Analysis of Outcomes following Initial Treatment Failure.

PURPOSE: Percutaneous nephrolithotomy has high potential for morbidity or failure. There are limited data regarding risk factors for failure and to our knowledge no published reports of surgical outcomes in patients with prior failed attempts at percutaneous stone removal. MATERIALS AND METHODS: We identified patients referred to 3 medical centers after prior failed attempts at percutaneous nephrolithotomy. A retrospective chart review was performed to analyze reasons for initial failure and outcomes of salvage percutaneous nephrolithotomy. Outcomes were compared to those in a prospectively maintained database of more than 1,200 patients treated with a primary procedure. RESULTS: Salvage percutaneous nephrolithotomy was performed in 31 patients. Unsuitable access to the stone was the reason for failure in 80% of cases. Other reasons included infection, bleeding and inadequate instrument availability in 6.5% of cases each. Compared to patients who underwent primary percutaneous nephrolithotomy those treated with salvage were more likely to have staghorn calculi (61.3% vs 31.4%, p <0.01) and a larger maximum stone diameter (3.7 vs 2.5 cm, p <0.01), and require a secondary procedure (65.5% vs 42.1%, p <0.01). There was no significant difference between the cohorts in the remaining demographics or perioperative outcomes. All patients were deemed completely stone free except one who elected observation for a 3 mm nonobstructing fragment. CONCLUSIONS: Despite the more challenging nature and prior unsuccessful attempts at treatment, the outcomes of salvage percutaneous nephrolithotomy were no different from those of primary percutaneous nephrolithotomy when performed by experienced surgeons.

Long-term follow-up of porcine dermis pubovaginal slings.

INTRODUCTION AND HYPOTHESIS: Outcomes of xenografts in incontinence surgery are uncommon. Our objective was to report long-term outcomes of women after porcine dermis (PD) bladder neck sling. METHODS: Seventy women completed a mean follow-up of 62.1 months. "Global cure" equaled SEAPI subjective composite = 0 and visual analog score ≥8. "Stress urinary incontinence (SUI) cure" equaled SEAPI-subjective (S) subset = 0 and negative cough stress test. RESULTS: The SUI cure rate was 42.9 % and global cure rate was 11.4 %. Perioperative complications were seen in <10 % of women. The mean time to SUI recurrence was 10.4 months, with 30 of 40 women redeveloping SUI <12 months after sling. Twenty women (28.6 %) have since undergone additional anti-incontinence procedures. There was a significant postoperative improvement in SEAPI scores, daily pad use, and quality of life (QOL) indices. CONCLUSIONS: 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.

Benign testicular neoplasm in a human immunodeficiency virus-positive patient masquerading as testicular cancer.

Inflammatory myofibroblastic tumor (IMT) is a rare, benign neoplasm comprising spindle myoepithelial cells in the background of inflammatory cells. It can involve multiple anatomic sites in the body but rarely involves the testis. We report a case of 52-year-old male patient with a history of human immunodeficiency virus who presented with a painless, testicular mass for 2 months. Despite being treated with prolonged antibiotics and nonsteroidal anti-inflammatory drugs, scrotal ultrasound demonstrated an increase in the size of the lesion. With a presumed diagnosis of testicular germ cell tumor, a right radical inguinal orchiectomy was performed. Microscopic and immunohistochemical features were consistent with testicular IMT, a benign neoplastic process.

Oxalate Concentrations in Human Gastrointestinal Fluid.

BACKGROUND AND PURPOSE: Urinary oxalate excretion is a risk factor for nephrolithiasis and is a result of endogenous metabolism and gastrointestinal processes. Gastrointestinal absorption of oxalate has been well demonstrated but to our knowledge evidence for secretion of oxalate is absent in humans. The objective of this study was to measure the amount and conformation of oxalate in the stomach and small intestine of adult subjects undergoing gastrointestinal endoscopy. MATERIALS AND METHODS: Eleven adults participated in this study. Gastrointestinal fluid was collected from the stomach and small intestine during endoscopy. A determination of the soluble and insoluble components of oxalate was made by centrifugation of the sample and subsequent acidification of the resultant pellet and supernatant. Samples were processed and the amount of oxalate was measured by ion chromatography, the limit of which is 1.6 µM. RESULTS: The majority of small intestinal samples contained some degree of oxalate. This is in contrast to the stomach where minimal oxalate was detected. There was a wide range of oxalate concentrations and a greater degree of insoluble oxalate in small intestinal samples. CONCLUSIONS: 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.

Optimizing Stone-free Rates With Ureteroscopy.

Ureteroscopy is being increasingly utilized in the treatment and management of patients with renal and ureteral stones. Improving stone-free rates with ureteroscopy decreases the need for ancillary procedures and improves patient outcomes and satisfaction. This article reviews contemporary literature regarding the efficacy of a wide range of currently available techniques for improving stone-free rates with this procedure.