Safety and efficacy of removable inferior vena cava filters in anticoagulated patients undergoing percutaneous nephrostolithotomy.

BACKGROUND AND PURPOSE: Increasing numbers of patients are receiving a diagnosis of thrombophilic conditions necessitating chronic anticoagulation therapy. The best management approach for such patients needing percutaneous nephrostolithotomy (PCNL) has not been established. Discontinuing anticoagulation therapy before PCNL is needed to prevent hemorrhage, placing some of these patients at risk for thromboembolic events. We describe the use of removable inferior vena cava filters (RIVCF) in patients undergoing PCNL who are at risk for a venous thromboembolic event. PATIENTS AND METHODS: A retrospective study of outcomes of PCNL with RIVCF placement was conducted. RESULTS: Four patients underwent PCNL with RIVCF placement on the same day of the procedure. The mean age was 49 years (range 35-69 years). PCNL was performed on a total of six renal units with a mean of 2.2 (range 1-3) operations per renal unit. Five of six (83%) renal units were rendered stone free. There were no complications associated with either the PCNL or RIVCF placement. No patient had a thromboembolic event or received blood products. Two of the four patients underwent successful removal of the RIVCF, and one elected to keep the device in place. The device could not be extracted in the other patient. The average length that the filters were in place was 52.5 days. Patients resumed anticoagulation therapy shortly after RIVCF removal. CONCLUSION: RIVCF placement is a safe and effective method of preventing venous thromboembolic complications in thrombophilic patients needing PCNL. Patients should be informed, however, that RIVCF removal is not always possible.

Is the Internet a reliable source for dietary recommendations for stone formers?

PURPOSE: Kidney stone formation is influenced by environmental factors, especially diet. Certain dietary modifications, including increased fluid intake, reduced animal protein and sodium consumption, and normal calcium intake, reduce the risk of stone activity. Patients frequently use the Internet for information regarding disease processes. We undertook this study to determine the quality of dietary stone information available in this communication domain. METHODS: The Google search engine was used to survey 458 consecutive sites related to kidney stones and dietary information. The presence or absence of the four aforementioned dietary recommendations was recorded. The sites were analyzed for correctness, information on all four domains present and correct; inaccuracy, something mentioned about all four areas but > or =1 recommendation error(s); deficiency, information on < or =3 or domains and no recommendation errors; deficiency and inaccuracy, information on < or =3 areas and > or =1 recommendation error(s). RESULTS: [Table: see text] There were 10 errors regarding calcium intake and 2 pertaining to protein consumption. The quality of information varied with the reporting source. CONCLUSIONS: Internet-based information regarding four important dietary modifications for kidney stone formers is frequently incomplete. Dietary inaccuracy, while uncommon in this communication domain, is mostly centered on the misconception that calcium restriction is beneficial. The quality of dietary information may depend on the Internet information source.

Effect of soda consumption on urinary stone risk parameters.

BACKGROUND AND PURPOSE: Fluid consumption has been demonstrated to influence kidney stone formation. Studies have shown that consumption of cola may be a risk factor for stone disease, while fluids containing citric acid may attenuate stone activity. Diet was not always controlled in these investigations, however. We undertook a study to determine the impact of three different fluids on urinary stone risk factors. SUBJECTS AND METHODS: Six healthy nonstone-forming adults were placed on a standardized metabolic diet and consumed three different types of fluid during three 5-day periods. There was a 2-day washout between each sequence. The three fluids administered during these periods were Le Bleu water, caffeine-free Diet Coke, and Fresca (citrate containing). These two soda preparations were chosen to prevent the known increase in calcium excretion promoted by carbohydrates and caffeine. Twenty-four hour urine specimens were collected on days 4 and 5 of each sequence. The following urinary parameters were measured: Volume, calcium, oxalate, creatinine, uric acid, citrate, sodium, magnesium, phosphorus, sulfate, urea nitrogen, pH, and supersaturation indices. A paired t test was used for statistical analysis. RESULTS: Urinary volumes were significantly higher and supersaturation of calcium oxalate significantly lower compared with a self-selected dietary regimen. A decrease in uric acid was also seen in the Fresca cohort. There were no statistically significant differences for any of the urinary parameters. CONCLUSION: There is no increased risk or benefit to consuming Fresca or caffeine-free Diet Coke compared with Le Bleu bottled water with respect to stone formation.

Prevalence of hyperoxaluria after bariatric surgery.

PURPOSE: Recent investigations have shown increased oxalate excretion in patients in whom kidney stones formed after contemporary bariatric surgery. We determined whether there is an increased prevalence of hyperoxaluria after such procedures performed in nonstone formers. MATERIALS AND METHODS: A total of 58 nonstone forming adults who underwent laparoscopic Roux-en-Y (52) or a biliopancreatic diversion-duodenal switch procedure (6) collected 24-hour urine specimens 6 months or greater after bariatric surgery. Standard stone risk parameters were assessed. Comparisons were made with a group of healthy nonstone forming adults and stone formers in a commercial database. RESULTS: The bariatric group had a significantly higher mean urinary oxalate excretion compared to that in controls and stone formers (67.2 vs 34.1 and 37.0 mg per day, respectively, p <0.001). Mean oxalate excretion of patients who underwent a biliopancreatic diversion-duodenal switch procedure was higher than in the Roux-en-Y group (90 vs 62 mg per day, p <0.05). There was a significant correlation between urine oxalate excretion on the 2 collection days but some patients showed significant variability. Of the patients 74% showed hyperoxaluria in at least 1, 24-hour urine collection and 26% demonstrated profound hyperoxaluria, defined as oxalate excretion more than 100 mg per day, in at least 1 collection. This occurred in 3 of the 6 patients in the biliopancreatic diversion-duodenal switch group and in 12 of the 52 in the Roux-en-Y cohort. Hyperoxaluria was not uniformly expressed. CONCLUSIONS: There is a high prevalence of hyperoxaluria in patients without a history of kidney stones who undergo bariatric surgery. A significant proportion of these patients have profound hyperoxaluria, which is not uniformly expressed.

Case report: bilateral hand-assisted laparoscopic nephrectomy in a patient with polycystic horseshoe kidney.

PURPOSE: To report the use of the hand-assisted laparoscopic (HAL) technique for removal of a horseshoe kidney in a patient with autosomal dominant polycystic kidney disease (ADPKD). CASE REPORT: Hospital and outpatient records were reviewed for a 65-year-old man with end-stage renal disease secondary to ADPKD who underwent HAL bilateral nephrectomy of his horseshoe kidney in preparation for kidney transplantation. The surgical method is described. It was completed successfully with an operative time of 280 minutes and an estimated blood loss of 350 mL. CONCLUSION: Bilateral HAL nephrectomy can be considered as an option for surgical removal of very large polycystic horseshoe kidneys.