Stern, Karen L

ABSTRACT Background Nephrolithiasis in allograft kidneys is rare, but this diagnosis may lead to allograft complications and patient morbidity. Previous studies that have evaluated nephrolithiasis posttransplant have focused on surgical stone management, with limited data on urine metabolic risk factors and the presence of stones after follow-up. Methods We retrospectively evaluated kidney transplant recipients who were diagnosed with transplant nephrolithiasis between 2009 and 2019. Computed tomography and ultrasound imaging were used to confirm stone presence. Results The incidence of allograft kidney stone formation was 0.86% of 6548 kidney transplant recipients. Of the 56 cases identified, 17 (30%) had a pretransplant history of nephrolithiasis. Only four (7%) patients received a known kidney stone at the time of allograft implantation. Of the 56 cases, 34 had a 24-h supersaturation study. The urine supersaturation study showed 32 patients (94%) had a urine citrate of <450 mg excreted in 24 h (median 124.5 mg/24 h, reference range >500 mg/24 h), along with 22 patients (61%) having a urine oxalate excretion of ≥30 mg in 24 h (median 34.4 mg/24 h, reference range <30 mg/24 h). Calcium oxalate composition was most common (91% with >1 supersaturation for calcium oxalate crystals), with normal median urine calcium levels (median urine calcium 103.5 mg/24 h, reference range <200 mg/24 h). After a 4-year follow-up, 50% (n = 28) required surgical intervention and 43 (77%) patients continued to have evidence of transplant nephrolithiasis on imaging. Conclusions This is the largest study of transplant nephrolithiasis confirming that hypocitraturia and hyperoxaluria were the most significant urine metabolic risk factors associated with allograft nephrolithiasis and that hyperoxaluria was the most prevalent driver for calcium oxalate stone composition. Our study is first to show low stone-free rates at the last follow-up and a significant proportion requiring surgical intervention.

Introduction: Currently, there are multiple intracorporeal lithotripters available for use in percutaneous nephrolithotomy (PCNL). This study aimed to evaluate the efficiency of two novel lithotripters: Trilogy and ShockPulse-SE. Materials and Methods: This is a prospective multi-institutional randomized trial comparing outcomes of PCNL using two novel lithotripters between February 2019 and June 2020. The study assessed objective measures of stone clearance time, stone clearance rate, device malfunction, stone-free rates, and complications. Device assessment was provided through immediate postoperative survey by primary surgeons. Results: There were 100 standard PCNLs completed using either a Trilogy or ShockPulse-SE lithotrite. Using quantitative Stone Analysis Software to estimate stone volume, the mean stone volume was calculated at 4.18 ± 4.79 and 3.86 ± 3.43 cm 3 for the Trilogy and ShockPulse-SE groups, respectively. Stone clearance rates were found to be 1.22 ± 1.67 and 0.77 ± 0.68 cm 3 /min for Trilogy vs ShockPulse-SE ( p = 0.0542). When comparing Trilogy to ShockPulse-SE in a multivariate analysis, total operative room time (104.4 ± 48.2 minutes vs 121.1 ± 59.2 minutes p = 0.126), rates of secondary procedures (17.65% vs 40.81%, p = 0.005), and device malfunctions (1.96% vs 34.69%, p < 0.001) were less, respectively. There was no difference in final stone-free rates between devices. Conclusion: Both the Trilogy and ShockPulse-SE lithotripters are highly efficient at removing large renal stones. In this study, we noted differences between the two devices including fewer device malfunctions when Trilogy device was utilized. Clinical Trial ID number: NCT03959683

Objectives To compare the enucleation efficiency of Moses 2.0 with non‐Moses technology in patients undergoing holmium laser enucleation of the prostate (HoLEP). Patients and Methods A double‐blinded, randomised study of patients undergoing HoLEP at the Mayo Clinic in Arizona, using the Lumenis Pulse™ 120H laser system. Patients were randomised to either right lobe enucleation using Moses 2.0 and left lobe enucleation using non‐Moses, or the opposite. The primary outcome was individual lobe enucleation efficiency. Secondary outcomes included individual lobe laser time, laser energy, individual enucleation and haemostasis laser energies, and fibre burn back. Two independent reviewers watched videos of the procedures and provided a subjective evaluation of the technologies. Results A total of 27 patients were included in the study. For the entire cohort, Moses 2.0 had less fibre degradation (3.5 vs 16.8 mm, P < 0.01) compared to non‐Moses. When HoLEP procedures were performed by an expert, Moses 2.0 resulted in shorter enucleation time (21 vs 36.7 min, P = 0.016) and higher enucleation efficiency (1.75 vs 1.05 g/min, P = 0.05) compared to non‐Moses. When HoLEP was performed by trainees, the Moses 2.0 cohort had a shorter haemostasis laser time (4.1 vs 9 min, P = 0.035) compared to the non‐Moses. Fibre degradation was lower with Moses 2.0 compared to non‐Moses for both experts and trainees. Moses 2.0 received a higher score than the standard technology for the incision sharpness, fibre control, tissue separation, tissue damage, haemostasis, visibility, and charring. The overall inter‐observer correlation coefficient was 0.63. Conclusion Moses 2.0 has higher enucleation efficiency compared to non‐Moses when used by experts. The subjective evaluation favoured Moses 2.0.

Background: Continent urinary diversion is a procedure commonly performed in patients after cystectomy who wish to not have a urostomy. Well-documented complications after continent urinary diversion include urinary tract infections and formation of urinary stones. However, these are typically late complications, and few reports have described the onset of these urinary symptoms within 12 months of initial continent urinary diversion. Case Presentation: Herein we report a case of a 41-year-old woman with history of cystectomy with continent urinary diversion who presents with recurrent infections and a calculus in the pouch 10 months after the initial procedure. Upon surgical exploration for removal of the stone, it was discovered that the stone was in fact a calcified retained catheter tip. Conclusion: This case further highlights that stone formation within 12 months of a urinary diversion is unusual and should prompt additional work-up for foreign body.