Burden of Urolithiasis: Trends in Prevalence, Treatments, and Costs.

CONTEXT: The recent evolution of management options for urolithiasis has presented a unique dilemma for the modern urologist. A comprehensive understanding of epidemiological trends along with current provider preferences in treating urinary stones would be beneficial. OBJECTIVE: To review trends in the prevalence, treatments, and costs of urolithiasis worldwide. EVIDENCE ACQUISITION: A literature review was performed using the MEDLINE database, the Cochrane Library Central search facility, Web of Science, and Google Scholar between 1986 and 2016. Keywords used for the search were "urolithiasis" and "prevalence; treatment; and cost". EVIDENCE SYNTHESIS: The incidence and prevalence of urinary stones are rising around the world, including regions that have historically had low rates of urolithiasis. Common theories explaining this trend involve climate warming, dietary changes, and obesity. Shockwave lithotripsy (SWL) has been the preferred mode of treatment since its introduction in the 1980s. However, ureteroscopy (URS) has become increasingly popular for small stones regardless of location because of lower recurrence rates and costs. Developing countries have been slower to adopt URS technology and continue to use percutaneous nephrolithotomy at a steady rate. CONCLUSIONS: URS has recently challenged SWL as the treatment modality preferred for small upper urinary tract stones. In some cases it is less expensive but still highly effective. As the burden of stone disease increases worldwide, appropriate selection of stone removal therapies will continue to play an important role and will thus require further investigation. PATIENT SUMMARY: Urinary stones are becoming more prevalent. Recent advances in technology have improved the management of this disease and have decreased costs.

Assessment of hydrodissection, holmium:YAG laser vaporization of renal tissue, and both combined to facilitate laparoscopic partial nephrectomy in porcine model.

OBJECTIVES: To evaluate the modalities of electrocautery, holmium:yttrium-aluminum-garnet (YAG) laser, hydrodissection, and combined holmium:YAG laser with hydrodissection applied to laparoscopic partial nephrectomy (LPN) in a porcine model. METHODS: A total of 16 Yorkshire pigs were divided into 4 equal groups (electrocautery, hydrodissection, holmium:YAG laser, and combined hydrodissection/holmium:YAG laser) and underwent unilateral LPN. The total operative time, partial nephrectomy time, hemostasis modality, and intraoperative complications were recorded. The pre- and postoperative hemoglobin was measured. Abdominal computed tomography was performed 2 weeks postoperatively. Representative specimens from each arm were examined for histologic findings. RESULTS: The mean total operative time and the time to perform partial nephrectomy was lower for the combined hydrodissection/holmium:YAG laser arm (66 minutes and 13 minutes, respectively) compared with the electrocautery arm (93 and 30 minutes, respectively), holmium:YAG laser-only arm (77 and 19 minutes, respectively), and hydrodissection-only arm (129 and 35 minutes, respectively). The mean decrease in hemoglobin was the least for the combined hydrodissection/holmium:YAG laser arm (5.3 g/L) followed by the holmium:YAG-only (15.3 g/L), hydrodissection-only (16.8 g/L), and electrocautery (35.5 g/L) arms, respectively. The histologic examination demonstrated an increased depth of tissue injury in the electrocautery arm. CONCLUSIONS: In a porcine model, the combined use of the hydrodissection/holmium:YAG laser to perform LPN had the shortest operative time and the lowest decrease in hemoglobin and appears to warrant additional clinical evaluation in human trials for LPN.

Swarming of Proteus mirabilis over ureteral stents: a comparative assessment.

BACKGROUND AND PURPOSE: Encrustation on indwelling ureteral stents is commonly related to the presence of urease-producing bacteria that elevate the pH of the urine through the hydrolysis of urea, resulting in the precipitation of calcium and magnesium salts. Using a model previously shown to measure accurately the ability of Proteus mirabilis to swarm over catheter surfaces (Eur J Clin Microbiol Infect Dis 1999;18:206), we investigated the ability of this organism to swarm over three ureteral stents with potential encrustation-resistance properties. MATERIALS AND METHODS: Three commercially available ureteral stents were selected for evaluation: a low surface-energy stent, a hydrogel-coated stent, and a silicone stent. Ten-microliter aliquots of a 4-hour culture of P. mirabilis 296 in Trypticase soya (TSA) broth was inoculated 5 mm from a 1-cm channel cut out from TSA plates. Ten-millimeter stent sections were placed as bridges across the central channel adjacent to the inocula. Time to pathogen crossing was measured. RESULTS: The mean time (+/- SD) to pathogen migration across the three test materials was 15.9 +/- 6.1, 19.8 +/- 9.5, and 29.7 +/- 14.3 hours for the low surface-energy, hydrogel-coated, and silicone stents, respectively. Statistical analysis revealed significant differences between the crossing times of the low surface-energy (P = 0.001) and hydrogel-coated (P = 0.034) stents compared with silicone but not between the low surface-energy and hydrogel-coated stents (P = 0.387). CONCLUSION: Migration of P. mirabilis 296 across silicone stents was significantly reduced compared with low surface-energy and hydrogel-coated stents. These findings suggest that P. mirabilis may have a lower affinity for silicone stents, which may translate into a reduced risk of infection with P. mirabilis and associated stent encrustation.