Not All Flat-Panel C-Arms Are Created Equal: A Comparison of Three Major Manufacturers.

Introduction: Flat-panel detector C-arms (FCs) are reported to reduce radiation exposure and improve image quality compared with conventional image intensifier C-arms (CCs). The purpose of this study was to compare radiation exposure and image quality between three commonly used FCs. Materials and Methods: A cadaver model was placed in the prone position to simulate percutaneous nephrolithotomy. We compared the following three FCs: OEC Elite CFD from GE HealthCare, Zenition 70 from Philips, and Ziehm Vision RFD from Ziehm Imaging. To measure the radiation dose, optically stimulated luminescence dosimeters (OSLDs) were utilized during five 300-second trials, conducted under three settings: automatic exposure control (AEC), AEC with low dose (LD), and LD with the lowest pulse rate (LDLP). Ten blinded urologists evaluated the image quality. Data were statistically analyzed using the analysis of variance (ANOVA) and Tukey's B post hoc tests. Results: In the AEC setting, the Philips C-arm demonstrated lower ventral OSLD exposure (42,446 mrad) compared with both the GE (51,076 mrad) and Ziehm (83,178 mrad; p < 0.001) C-arms. Similarly, in the LD setting, the Philips C-arm resulted in less ventral OSLD exposure (25,926 mrad) than both the Ziehm (30,956 mrad) and GE (38,209 mrad; p < 0.001) C-arms. Meanwhile, in the LDLP setting, the Ziehm C-arm showed less ventral OSLD exposure (4019 mrad) than both the GE (7418 mrad) and Philips (8229 mrad; p < 0.001) C-arms. All three manufacturers received adequate image quality ratings at the AEC and LD settings. However, at LDLP, the Ziehm C-arm received inadequate ratings in 8% of images, whereas both the GE and Philips C-arms received 100% adequate ratings (p = 0.016). Conclusions: Radiation produced by flat-panel C-arms varies dramatically, with the highest exposure (Ziehm) being almost double the lowest (Philips) in AEC. Improved picture quality at the lowest settings may come at the cost of increased radiation dose. Surgeons should carefully select the machine and settings to minimize radiation exposure while still preserving the image quality.

Reducing hand radiation during renal access for percutaneous nephrolithotomy: a comparison of radiation reduction techniques.

Percutaneous nephrolithotomy confers the highest radiation to the urologist's hands compared to other urologic procedures. This study compares radiation exposure to the surgeon's hand and patient's body when utilizing three different techniques for needle insertion during renal access. Simulated percutaneous renal access was performed using a cadaveric patient and separate cadaveric forearm representing the surgeon's hand. Three different needle-holding techniques were compared: conventional glove (control), a radiation-attenuating glove, and a novel needle holder. Five 300-s fluoroscopy trials were performed per treatment arm. The primary outcome was radiation dose (mSv) to the surgeon's hand. The secondary outcome was radiation dose to the patient. One-way ANOVA and Tukey's B post-hoc tests were performed with p < 0.05 considered significant. Compared to the control (3.92 mSv), both the radiation-attenuating glove (2.48 mSv) and the needle holder (1.37 mSv) reduced hand radiation exposure (p < 0.001). The needle holder reduced hand radiation compared to the radiation-attenuating glove (p < 0.001). The radiation-attenuating glove resulted in greater radiation produced by the C-arm compared to the needle holder (83.49 vs 69.22 mGy; p = 0.019). Patient radiation exposure was significantly higher with the radiation-attenuating glove compared to the needle holder (8.43 vs 7.03 mSv; p = 0.027). Though radiation-attenuating gloves decreased hand radiation dose by 37%, this came at the price of a 3% increase in patient exposure. In contrast, the needle holder reduced exposure to both the surgeon's hand by 65% and the patient by 14%. Thus, a well-designed low-density needle holder could optimize radiation safety for both surgeon and patient.

Does renal failure worsen radiation cystitis following radical prostatectomy?

OBJECTIVE: To investigate the impact of renal function on the risk, severity, and management of radiation cystitis in patients who underwent postoperative radiation therapy for prostate cancer. METHODS: Retrospective data was assessed from patients treated with adjuvant/salvage radiation therapy at a single academic institution between 2006 and 2020. The incidence, severity, and management of radiation cystitis were compared between three groups: CKD 0-2, CKD 3-4, and CKD 5. Associations of clinicopathologic factors with radiation cystitis were assessed in univariate and multivariate Cox regression models. RESULTS: A total of 110 patients who underwent radiation therapy following robot-assisted laparoscopic radical prostatectomy were included. The incidence of radiation cystitis following postoperative radiation therapy was 17% with a median presentation time of 34 months (interquartile range 16-65 months). The incidence of radiation cystitis was 100% in CKD 5 patients compared to 15% in CKD 0-2 and 17% in CKD 3-4 patients (p < 0.001). CKD 5 patients required more treatments, emergency department visits, and longer hospitalization times than CKD 0-4 patients (all p < 0.001). Multivariate analyses identified CKD 5 as the only significant factor associated with radiation cystitis (HR = 10.39, p = 0.026). CONCLUSION: End-stage renal failure is associated with the risk and severity of radiation cystitis in patients receiving postoperative radiation therapy. Knowledge of the potential morbidity of this complication in this population could guide physicians and patients as they evaluate risks and benefits prior to selecting adjuvant or salvage radiation therapy.

The Pseudo-Bladder: A Case of the Prostatic Urethra Masquerading as the Bladder.

Congenital bladder underdevelopment has detrimental genitourinary effects. We present a male infant with declining renal function, recurrent urinary tract infections, and epididymo-orchitis, in the setting of bilateral high grade hydronephrosis and vesicoureteral reflux. Cystoscopic evaluation revealed the presumed "bladder" to be a massively dilated prostatic urethra. The small dysplastic "true bladder" was found at the anterior surface of the prostatic urethra with massively dilated ureteral orifices. Temporizing diversion was performed in the form of bilateral cutaneous ureterostomies, with an ultimate plan for reconstructive bladder surgery. This case presents diagnostic challenges utilizing current modalities due to a massively dilated prostatic urethra in the rare case of bladder dysplasia.

Thulium versus holmium for in situ lower pole laser lithotripsy.

INTRODUCTION: During in situ lower pole laser lithotripsy, the dependent location may result in increased challenge fragmenting stones and a risk for stone regrowth if residual fragments remain. The purpose of this study was to compare the thulium fiber laser (TFL) with the holmium laser (HL) for in situ lower pole lithotripsy. MATERIALS AND METHODS: In a 3D printed kidney benchtop model, sixty 1 cm BegoStones were placed in the lower pole and fragmented in situ until fragments passed through a 2 x 2 mm mesh. Laser lithotripsy was performed using twelve energy, frequency and fiber size combinations and residual fragments were compared. In addition, laser fiber diameters and subsequent ureteroscope deflections and flow rates were compared between fibers. RESULTS: The TFL resulted in decreased residual fragments compared to the HL (11% vs. 17%, p < 0.001) and the three settings with least residual fragments were all TFL. Compared to the 150 µm TFL (265° deflection), there was a loss of 9° and 34° in the 200 µm TFL and 272 µm HL fibers, respectively. The measured fiber sizes were greater than manufacturer specified fiber size in every instance. Irrigation rates inversely correlated with fiber size. CONCLUSION: The TFL resulted in 35% less residual stone fragments, up to 34° additional deflection, and an increased irrigation rate when compared to the HL. Optimal fragmentation settings are identified to further improve lower pole lithotripsy. The combination of reduced residual fragments, improved deflection, and better flow rates make the TFL advantageous for in situ lower pole lithotripsy.

Oxidative stress in the pathophysiology of male infertility.

The effects of reactive oxygen species on male fertility are governed by the oxidative paradox, defined by a delicate balance between oxidative stress and antioxidant capacity. When regulated appropriately, reactive oxygen species ensure effective function; however, when uninhibited, they represent key players in male factor infertility. Mechanisms responsible for this include oxidative destruction of sperm lipid membranes, damage to gamete DNA both by gene mutation and by direct breakdown of the DNA backbone, mitochondrial dysfunction and apoptotic cell death. Utilizing various male pathologies as case studies, we see ways in which oxidative stress has the potential to impact fertility in a negative way. Varicocele, erectile dysfunction, testicular cancer and even idiopathic male infertility highlight common mechanistic pathways, as well as subtle variations in the ways reactive oxygen species can operate. Oxidative biomarkers have emerged to better study male infertility, predict reproductive success and modify assisted reproductive technologies to minimize oxidative stress.

Bilateral Ureteroenteric Strictures: A Case of the "Reverse 7".

Anastomotic stricture is a well-known complication of the urinary diversion that accompanies radical cystectomy. Management options range from endoscopic procedures to open surgeries, with a subset of the latter employing bowel as the interposing segment. In this report, we describe a rare patient, who successfully underwent a "Reverse 7" procedure, bypassing strictures at both anastomotic junctions between ureters and neobladder.

The disappearing PI-RADS 5 prostate lesion.

Prostate Imaging Reporting and Data System version 2 (PI-RADS v2) identifies prostate cancer on the basis of multiparametric MRI (mpMRI). As an assessment tool, it correctly predicts clinically significant cancer in the vast majority of cases. In this light, we report a rare patient, for whom a PI-RADS 5 lesion vanished over the course of 13 months.

Jackets Off: The Impact of Laser Fiber Stripping on Power Output and Stone Degradation.

PURPOSE: To investigate the effect of laser fiber stripping on stone fragmentation and laser fiber power output. MATERIALS AND METHODS: In a benchtop simulation of laser lithotripsy, 20 BegoStone phantoms were positioned within a ureteral model and irradiated for 10 minutes at 8 Hz and 0.8 J. A freshly cleaved 365 µm laser fiber was used for all trials, with half of the fibers also undergoing stripping. Power output was measured at 1-minute intervals, beginning with an initial prelithotripsy recording at 0 minutes. Fiber tips were imaged with scanning electron microscopy. In a single-blinded manner, final masses of residual stone fragments were measured and used to quantify stone breakdown. Independent-sample Mann-Whitney U tests were performed with significance set at p < 0.05, comparing stripped and unstripped fiber tips with respect to power output and fraction of stone fragmentation. RESULTS: Mean power output after 1 minute of lasing was significantly greater in unstripped laser fibers (p = 0.015), while fibers, whether stripped or not, demonstrated no significant output differences prelithotripsy or at any time from 2 to 10 minutes. However, stripped laser fibers achieved significantly increased stone breakdown compared to unstripped fibers (p = 0.004), fragmenting 63 mg (25%) more of the initial stone mass per trial. CONCLUSIONS: Although unstripped laser fibers provided superior power output at 1 minute, output at all other time points was similar between stripped and unstripped fibers. However, despite similar optical output, stripped laser fibers achieved greater stone fragmentation, possibly due to improved contact between stone and fiber tip.

Development of siRNA payloads to target KRAS-mutant cancer.

UNLABELLED: RNAi is a powerful tool for target identification and can lead to novel therapies for pharmacologically intractable targets such as KRAS. RNAi therapy must combine potent siRNA payloads with reliable in vivo delivery for efficient target inhibition. We used a functional "Sensor" assay to establish a library of potent siRNAs against RAS pathway genes and to show that they efficiently suppress their targets at low dose. This reduces off-target effects and enables combination gene knockdown. We administered Sensor siRNAs in vitro and in vivo and validated the delivery of KRAS siRNA alone and siRNA targeting the complete RAF effector node (A/B/CRAF) as promising strategies to treat KRAS-mutant colorectal cancer. We further demonstrate that improved therapeutic efficacy is achieved by formulating siRNA payloads that combine both single-gene siRNA and node-targeted siRNAs (KRAS + PIK3CA/B). The customizable nature of Sensor siRNA payloads offers a universal platform for the combination target identification and development of RNAi therapeutics. SIGNIFICANCE: To advance RNAi therapy for KRAS-mutant cancer, we developed a validated siRNA library against RAS pathway genes that enables combination gene silencing. Using an in vivo model for real-time siRNA delivery tracking, we show that siRNA-mediated inhibition of KRAS as well as RAF or PI3K combinations can impair KRAS-mutant colorectal cancer in xenograft models.

Hypocretin ligand deficiency in narcolepsy: recent basic and clinical insights.

Narcolepsy is a chronic sleep disorder characterized by excessive daytime sleepiness, cataplexy, hypnagogic hallucinations, and sleep paralysis. Both sporadic and familial forms exist in humans. Recently, the major pathophysiology of human narcolepsy was indicated, based on discovery, through animal study, of narcolepsy genes involved in the pathology of hypocretin/orexin ligand and its receptor. Hypocretin ligand deficiency is found in most patients with narcolepsy with cataplexy. This deficiency likely is the result of postnatal cell death of hypocretin neurons, and involvement of autoimmune mechanisms is suggested. Hypocretin deficiency also is found in symptomatic narcolepsy and excessive daytime sleepiness with neurologic conditions, including immune-mediated neurologic disorders. These findings have significant clinical relevance and promote understanding of hypocretin cell death mechanisms. Already, discoveries in humans have led to a new diagnostic test for narcolepsy. Currently, hypocretin replacement therapy has emerged as a promising therapeutic option, and experiments using gene therapy and cell transplantation are in progress.