Laparoscopic heminephrectomy was performed in a 64-year-old woman with a chronically obstructed horseshoe kidney moiety. More than 3000 cc of pyonephrosis was drained through two percutaneous nephrostomy tubes for infection control before left moiety laparoscopic resection. This case report attests to the feasibility of laparoscopic resection of a massively obstructed horseshoe kidney when performed in a staged manner after prolonged drainage. Since an incision was required for removal of the large specimen, ligation of the horseshoe isthmus was completed through the same incision after hilar control and laparoscopic mobilization of the moiety were completed.

Laparoscopic heminephrectomy was performed in a 64-year-old woman with a chronically obstructed horseshoe kidney moiety. More than 3000 cc of pyonephrosis was drained through two percutaneous nephrostomy tubes for infection control before left moiety laparoscopic resection. This case report attests to the feasibility of laparoscopic resection of a massively obstructed horseshoe kidney when performed in a staged manner after prolonged drainage. Since an incision was required for removal of the large specimen, ligation of the horseshoe isthmus was completed through the same incision after hilar control and laparoscopic mobilization of the moiety were completed.

STUDY OBJECTIVES:To delineate the relationship between sleep apnea and subsequent risk of nephrolithiasis. METHODS:We conducted a retrospective cohort analysis of a general population sample from Taiwan National Health Insurance Research Database (NHIRD) from January 1, 2000 to December 31, 2012. Patients with sleep apnea without prior diagnosis of nephrolithiasis (n = 7,831) were identified and subsequent development of nephrolithiasis was compared to an age- and sex-matched control group (n = 31,293) without sleep apnea. The Cox proportional hazard regression models were used to evaluate the association between sleep apnea and subsequent nephrolithiasis development. RESULTS:After adjusting for age, sex, and comorbidities, the risk of nephrolithiasis remained significantly increased in the sleep apnea group (hazard ratio [HR] = 1.35; 95% confidence interval [CI] = 1.23-1.48; P < .001). Compared to controls, elevated HRs of nephrolithiasis were observed for male patients (HR = 1.22; 95% CI 1.09-1.36; P < .001) and those aged 20-39 years (HR = 1.28; 95% CI 1.09-1.49; P < .01) and 40-59 years (HR = 1.17, 95% CI 1.03-1.34, P < .05) in the sleep apnea cohort. Risk of nephrolithiasis in patients with sleep apnea increased significantly with concomitant metabolic-related comorbidities, gouty arthritis, and urinary tract infection. CONCLUSIONS:Sleep apnea is associated with an increased subsequent risk of the development of nephrolithiasis. Young male patients with sleep apnea and concomitant comorbidities are at the greatest risk for nephrolithiasis formation.

INTRODUCTION:Reusable ureteroscope durability and need for repair are significant sources of expense and inefficiency for patients and urologists. Utilization of LithoVue™, a disposable flexible digital ureteroscope, may address some of these concerns. To identify its economic impact on clinical care, we performed a micro-cost comparison between flexible reusable fiberoptic ureteroscopes (URF-P6™) and LithoVue. PATIENTS AND METHODS:For this prospective, single-center micro-costing study, all consecutive ureteroscopies performed during 1 week each in July and August 2016 utilized either URF-P6 or LithoVue ureteroscopes respectively. Workflow data were collected, including intraoperative events, postoperative reprocessing cycle timing, consumables usage, and ureteroscope cost data. RESULTS:Intraoperative data analysis showed mean total operating room time for URF-P6 and LithoVue cases were 93.4 ± 32.3 and 73.6 ± 17.4 minutes, respectively (p = 0.093). Mean cost of operating room usage per case was calculated at $1618.72 ± 441.39 for URF-P6 and $1348.64 ± 237.40 for LithoVue based on institutional cost rates exclusive of disposables. Postoperative data analysis revealed costs of $107.27 for labor and consumables during reprocessing for URF-P6 cases. The costs of ureteroscope repair and capital acquisition for each URF-P6 case were $957.71 and $116.02, respectively. The total ureteroscope cost per case for URF-P6 and LithoVue were $2799.72 and $2852.29, respectively. CONCLUSIONS:Micro-cost analysis revealed that the cost of LithoVue acquisition is higher per case compared to reusable fiberoptic ureteroscopes, but savings are realized in labor, consumables, and repair. When accounting for these factors, the total cost per case utilizing these two ureteroscopes were comparable.

Objectives

To compare perioperative outcomes of robotic-assisted partial nephrectomy (RaPN) with open partial nephrectomy (OPN).

Methods

Systematically search through PubMed, Embase, ClinicalKey, Cochrane Library, ProQuest, ScienceDirect, Web of Science, and ClinicalTrials.gov for eligible studies was performed to April 11, 2018. A meta-analysis was conducted for studies comparing RaPN and OPN. Confounding variables were assessed by meta-regression or subgroup analysis.

Results

This study included 34 studies with 60 808 patients. Meta-analysis revealed less blood loss, less transfusion, longer operative time, less postoperative complications, lower readmission rate, shorter length of stay, and less estimated glomerular filtration rate (eGFR) decline in RaPN groups. The superiority of RaPN in blood loss was attenuated with highly complex renal masses. The superiority of RaPN in intraoperative complications was strengthened with renal hilar control. The advantage of RaPN in surgical margin was increased in patient with body mass index (BMI) < 28.

Conclusions

Compared with OPN, RaPN provided lower morbidities and better renal function preservation.

INTRODUCTION:Cystinuria is a genetic disorder marked by elevated urinary cystine excretion and recurrent cystine nephrolithiasis. Interestingly, despite seemingly similar contralateral renal anatomy, a subset of cystinuric patients consistently form stones in only one kidney. The aim of this study is to evaluate clinical outcomes in unilateral vs bilateral cystine stone formers. PATIENTS AND METHODS:We performed a retrospective case-control study of cystinuric patients evaluated and treated at the University of California, San Francisco between 1994 and 2015 and categorized patients as either unilateral or bilateral stone formers. Clinical presentation, baseline patient demographics, stone procedures, medical therapy regimens, and long-term renal function were compared between the two groups. RESULTS:A total of 42 cystine stone patients (22 female, 20 male) were included in the analysis. The median age at first presentation was 18.5 years and median age at study conclusion was 45.5 years. Two-thirds of patients (n = 28) had a history of bilateral stones, whereas one-third (n = 14) had unilateral stones. Medical therapy regimens were similar between groups. Despite an increased average number of lifetime surgeries (7.5 sessions for bilateral vs 3.7 sessions for unilateral, p < 0.05), there was no significant difference in medians of the most recent glomerular filtration rate when compared with unilateral stone formers (81.5 vs 95 mL/min, respectively; p = 0.28). CONCLUSIONS:The majority of cystinuric patients within our cohort form stones bilaterally during their lifetime, and require more surgical interventions than unilateral stone formers. Despite this, overall renal function is well preserved in unilateral and bilateral cystinuric stone formers treated with minimally invasive stone extraction procedures.

Calcium-based renal calculi demonstrated significant heterogeneity in the structure, density, mineral composition, and material hardness not elucidated by routine clinical testing. Mineral density distributions within calcium oxalate stones revealed differential areas of low (590±80 mg/cc), medium (840±140 mg/cc), and high (1100±200 mg/cc) densities. Apatite stones also contained regions of low (700±200 mg/cc), medium (1100±200 mg/cc), and high (1400±140 mg/cc) densities within layers extending from single or multiple nucleation sites. Despite having lower average mineral density, calcium oxalate (CaOx) stones demonstrated higher material hardness compared to apatite stones, suggesting other chemical components might be involved in determining stone hardness properties. Carbon concentrated sites were identified between morphologic layers in CaOx stones and in stratified layers of apatite stones. Elemental analyses revealed numerous additional trace elements in both stone types. Despite the widespread assumption that stone mineral density is an indicator of susceptibility to lithotripsy, calcium stone mineral density estimates do not directly correlate with actual ex vivo stone hardness. Underlying stone heterogeneity in both structure and mineral density could explain why historical approaches have failed in accurately predicting response of stones to lithotripsy.

The development of new modalities for kidney stone prevention rests upon understanding the progression of mineralization within the renal pyramid. The progression from small foci of mineralized volumes within the renal pyramid to larger interstitial plaques that ultimately lead into clinically detectable calcium-based stones on calcium phosphate stems will be presented through correlative microscopy approach. High resolution X-ray computed tomography (micro-XCT), electron microscopy, and energy dispersive X-ray (EDX) compositional analyses of interstitial plaques, stems, and attached stones were performed. Increase in mineral density progressed with mineralization severity, with the highest mineral densities detected within mature Randall's plaque and stems to which kidney stones were attached. EDX analyses revealed variable elemental composition within interstitial plaque, stems, and stones. Micro-XCT reconstructions of stones with stems enabled visualization of unoccluded tubules within stems, with average tubule diameters corresponding to thin limbs of Henle, blood vessels, and collecting ducts. Correlative microscopy confirmed that the progression of mineralization leading to calcium-based nephrolithiasis occurs through a continuum involving four anatomically and structurally distinct biomineralization regions: 1) proximal intratubular mineralization within the renal pyramid; 2) interstitial Randall's plaque near the tip of the papilla; 3) emerging plaque (stems); and, 4) the body of heterogeneous stones.

Statement of significance

Nephrolithiasis is a common condition affecting nearly 1 in 11 Americans. The most common type of stone, calcium oxalate is known to form on a calcium phosphate deposit on the renal papilla known as Randall's plaque. Novel imaging techniques have identified distinct regions of biomineralization not just at the tip, but throughout the renal papilla. The classic understanding of Randall's plaque formation is reformulated using correlative imaging techniques. This study establishes a stepwise progression of anatomically-specific biomineralization events including, 1) proximal intratubular mineralization within the renal pyramid; 2) interstitial Randall's plaque near the tip of the papilla; 3) emerging plaque (stems); and, 4) the body of heterogeneous stones, and provides insights into the need for plausible site-specific therapeutic intervention.

INTRODUCTION:Cystinuria is a genetic disorder marked by elevated urinary cystine excretion and recurrent cystine nephrolithiasis. Interestingly, despite seemingly similar contralateral renal anatomy, a subset of cystinuric patients consistently form stones in only one kidney. The aim of this study is to evaluate clinical outcomes in unilateral vs bilateral cystine stone formers. PATIENTS AND METHODS:We performed a retrospective case-control study of cystinuric patients evaluated and treated at the University of California, San Francisco between 1994 and 2015 and categorized patients as either unilateral or bilateral stone formers. Clinical presentation, baseline patient demographics, stone procedures, medical therapy regimens, and long-term renal function were compared between the two groups. RESULTS:A total of 42 cystine stone patients (22 female, 20 male) were included in the analysis. The median age at first presentation was 18.5 years and median age at study conclusion was 45.5 years. Two-thirds of patients (n = 28) had a history of bilateral stones, whereas one-third (n = 14) had unilateral stones. Medical therapy regimens were similar between groups. Despite an increased average number of lifetime surgeries (7.5 sessions for bilateral vs 3.7 sessions for unilateral, p < 0.05), there was no significant difference in medians of the most recent glomerular filtration rate when compared with unilateral stone formers (81.5 vs 95 mL/min, respectively; p = 0.28). CONCLUSIONS:The majority of cystinuric patients within our cohort form stones bilaterally during their lifetime, and require more surgical interventions than unilateral stone formers. Despite this, overall renal function is well preserved in unilateral and bilateral cystinuric stone formers treated with minimally invasive stone extraction procedures.

Limited information exists on the anatomically-specific early stage events leading to clinically detectable mineral aggregates in the renal papilla. In this study, quantitative multiscale correlative maps of structural, elemental and biochemical properties of whole medullo-papillary complexes from human kidneys were developed. Correlative maps of properties specific to the uriniferous and vascular tubules using high-resolution X-ray computed tomography, scanning and transmission electron microscopy, energy dispersive X-ray spectroscopy, and immunolocalization of noncollagenous proteins (NCPs) along with their association with anatomy specific biominerals were obtained. Results illustrated that intratubular spherical aggregates primarily form at the proximal regions distant from the papillary tip while interstitial spherical and fibrillar aggregates are distally located near the papillary tip. Biominerals at the papillary tip were closely localized with 10 to 50 μm diameter vasa recta immunolocalized for CD31 inside the medullo-papillary complex. Abundant NCPs known to regulate bone mineralization were localized within nanoparticles, forming early pathologic mineralized regions of the complex. Based on the physical association between vascular and urothelial tubules, results from light and electron microscopy techniques suggested that these NCPs could be delivered from vasculature to prompt calcification of the interstitial regions or they might be synthesized from local vascular smooth muscle cells after transdifferentiation into osteoblast-like phenotypes. In addition, results provided insights into the plausible temporal events that link the anatomically specific intratubular mineral aggregates with the interstitial biomineralization processes within the functional unit of the kidney.