Endourologic Procedures of the Upper Urinary Tract and the Effects on Intrarenal Pressure and Temperature.

Introduction: Endourologic procedures, including ureteroscopy (URS) and percutaneous nephrolithotomy (PCNL), are associated with an elevation in intrarenal pressures (IRPs) and irrigation temperatures. Recent research has focused on methods to reduce IRP and irrigation temperatures, with the ultimate goal to limit the consequences associated with these deviations. The purpose of our study is to provide a narrative review on the effects of endourologic procedures on pressure and temperature and provide recommendations to minimize these changes. Methods: A literature review was performed using PubMed. The search was limited to English human and nonhuman studies. Abstracts were reviewed for inclusion in our narrative review. Results: Human and animal models suggest that URS and PCNL are associated with peak IRPs above a "safe" threshold. Strategies to minimize pressures focus on minimizing irrigation flow into the upper tract and maximizing flow out of the system. High IRP has been associated with postoperative pain and infectious complications. Elevated irrigation temperatures are associated with high-power lasers during URS. Strategies to minimize irrigation temperatures focus on maximizing irrigation flow during laser activation and minimizing thermal energies associated with lithotripsy. Conclusions: Rises in pressure and irrigation temperatures associated with endourologic procedures are becoming increasingly recognized in the urologic community. Human studies examining "safe" thresholds for IRP and irrigation temperatures are limited. Temperature- and pressure-sensing technologies will aid in identifying the clinical consequences of elevated IRPs and irrigation temperatures, resulting in strategies to minimize them.

Impact of LUTS on urine volume in stone formers The impact of lower urinary tract symptomatology on urine volumes in stone formers.

INTRODUCTION: We aimed to determine if there is a correlation between International Prostate Symptom scores (IPSS) and 24-hour urine collection volumes, as patients experiencing lower urinary tract symptoms (LUTS) may have impaired ability to increase fluid intake for stone prevention. METHODS: We conducted a single-centre, retrospective review was performed of stone-formers presenting from 2014-2016. Inclusion criteria were completion of an IPSS questionnaire and a 24-hour urine collection. Exclusion criteria included symptomatic stone or urinary tract infection at time of IPSS completion, inadequate 24-hour collection, or incomplete IPSS questionnaire. RESULTS: A total of 131 patients met inclusion criteria. Stratification by IPSS severity into mild (0-7), moderate (8-19), and severe (20-35) yielded groups of n=96, 28, and 7, respectively. Linear regression modelling did not reveal a correlation between IPSS score and volume (p=0.10). When compared to those with adequate urine volumes (>2 L/day, n=65), low-volume patients (<1 L/day, n=10) had a significantly higher total IPSS (11.7 vs. 6.1; p=0.036). These groups showed significant differences in their responses to questions about incomplete emptying (p=0.031), intermittency (p=0.011), and stranguria (p=0.0020), with higher scores noted in the low urine output group. CONCLUSIONS: This study is the first to examine the correlation between IPSS and 24-hour urine volume. Though our data does not show a linear relationship between urine output and IPSS, those with lower urine volumes appear to have worse self-reported voiding symptoms when compared to those with adequate volumes (>2 L/day) for stone prevention. The overall number of patients in our study is relatively small, which may account for the lack of a relationship between IPSS and 24-hour urine volumes.