Quick Sequential Organ Failure Assessment Score Is a Better Predictor of Septic Shock After Percutaneous Nephrolithotomy: A Secondary Analysis of Two Multicenter Prospective Trials.

Introduction: Recent retrospective literature suggests that the quick sequential organ failure assessment (qSOFA) scoring tool is a potentially superior tool over use of the systemic inflammatory response syndrome (SIRS) criteria to predict septic shock after percutaneous nephrolithotomy (PCNL) surgery. Here we examine use of qSOFA and SIRS to predict septic shock within data series collected prospectively on PCNL patients as part of a greater study of infectious complications. Materials and Methods: We performed a secondary analysis of two prospective multicenter studies including PCNL patients across nine institutions. Clinical signs informing SIRS and qSOFA scores were collected no later than postoperative day 1. The primary outcome was sensitivity and specificity of SIRS and qSOFA (high-risk score of greater-or-equal to two points) in predicting admission to the intensive care unit (ICU) for vasopressor support. Results: A total of 218 cases at 9 institutions were analyzed. One patient required vasopressor support in the ICU. The sensitivity/specificity was 100%/72.4% (McNemar's test p < 0.001) for SIRS and was 100%/90.8% (McNemar's test p < 0.001) for qSOFA. Conclusion: Although positive predictive value for both qSOFA and SIRS in prediction of post-PCNL septic shock is low, prospectively collected data demonstrate use of qSOFA may offer greater specificity than SIRS criteria when predicting post-PCNL septic shock.

The Fate of Residual Fragments After Percutaneous Nephrolithotomy: Results from the Endourologic Disease Group for Excellence Research Consortium.

Background: Residual fragments (RFs) after percutaneous nephrolithotomy (PCNL) have a significant impact on patients' quality of life and clinical course. There is a paucity of studies that evaluate the natural history of RFs after PCNL. The objective of this study is to compare rates of reintervention, complications, stone growth, and passage in patients with RFs >4, ≤4, and ≤2 mm after PCNL. Methods: Sites from the Endourologic Disease Group for Excellence (EDGE) research consortium examined data of PCNL patients from 2015 to 2019 with at least 1-year follow-up. RF passage, regrowth, reintervention, and complications were recorded and RFs were stratified into >4 and ≤4 mm groups, as well as >2 and ≤2 mm groups. Potential predictors for stone-related events after PCNL were determined using multivariable logistic regression analysis. It was hypothesized that larger RF thresholds would result in lower passage rates, faster regrowth, and greater clinically significant events (complications and reinterventions) than smaller RF thresholds. Results: A total of 439 patients with RFs >1 mm on CT postoperative day 1 were included in this study. For RFs >4 mm, rates of reintervention were found to be significantly higher and Kaplan-Meier curve analysis showed significantly higher rates of stone-related events. Passage and RF regrowth were not found to be significantly different compared with RFs ≤4 mm. However, RFs ≤2 mm had significantly higher rates of passage, and significantly lower rates of fragment regrowth (>1 mm), complications, and reintervention compared with RFs >2 mm. On multivariable analysis, older age, body mass index, and RF size were found to be predictive of stone-related events. Conclusions: With the largest cohort to date, this study by the EDGE research consortium further confirms that clinically insignificant residual fragment is problematic for patients after PCNL, particularly in older more obese patients with larger RFs. Our study underscores the importance of complete stone clearance post-PCNL and challenges the use of Clinically insignificant residual fragment (CIFR).

Health-related quality of life disparities among Hispanic/Latinx patients with nephrolithiasis.

It is documented that Hispanic/Latinx kidney stone formers have inferior health-related quality of life (HRQoL) compared to the general population. We hypothesized that socioeconomic factors drive HRQoL disparities. Specifically, we sought to determine if medical insurance type is associated with HRQoL disparities among Hispanic/Latinx stone formers. This was a prospective cohort observational study of patients with kidney stones across the University of San Diego Health Care System. Patients enrolled from June 2018 to August 2020 completed a validated Wisconsin Stone Quality of Life questionnaire (WISQoL). Patient characteristics and self-reported HRQoL were compared between Hispanic/Latinx and non-Hispanic/Latinx stone formers using MANCOVA and ordinal logistic regression. Matched group comparisons were performed based on age, gender, body mass index, stone symptoms, and insurance type using MACOVA. A total of 270 patients were enrolled (Hispanic/Latinx n = 88; non-Hispanic/Latinx n = 182). Hispanic/Latinx stone formers had higher rates of public insurance at baseline (p < 0.001) with significantly lower HRQoL [social impact (p = 0.007)]. However, a matched cohort comparison demonstrated no differences. On multivariate analysis, private insurance increased the likelihood of having higher HRQoL (OR 2.21, p = 0.021), while stone symptoms (OR = 0.06, p < 0.001) and emergency department visits (OR = 0.04, p = 0.008) decreased chances of higher HRQoL. Ethnicity was not a significant factor in HRQoL scores on multivariate analysis. Our analysis suggests that differences in HRQoL among Hispanic/Latinx stone formers may be primarily driven by socioeconomic factors as opposed to clinical or racial differences. Specifically, source of insurance appears to have significant effect on HRQoL in this ethnic group.

Epithelioid Hemangioma of the Glans Penis in an Adolescent Male: A Case Report.

Epithelioid hemangioma is a rare vascular lesion consisting of capillaries and inflammatory infiltrate containing lymphocytes, and mast cells. The presentation of penile epithelioid hemangioma has been previously described in the adult literature; however, few cases have been reported in the pediatric population. Herein we present a case of penile epithelioid hemangioma in a 15-year-old patient with regrowth following surgical resection, requiring more extensive surgical excision with urethral reconstruction. This rare case highlights the importance of a proper diagnosis and complete microscopic removal.

Understanding Causes for Admission in Planned Ambulatory Percutaneous Nephrolithotomy.

Introduction: For treatment of nephrolithiasis, ambulatory percutaneous nephrolithotomy (aPCNL) is growing in popularity for select patients. The aim of this study was to investigate the safety and efficacy of a set of aPCNL selection criteria as well as search for predictors of failed aPCNL resulting in inpatient admission. Materials and Methods: We reviewed all percutaneous nephrolithotomy (PCNL) patients from 2016 to 2020. A total of 175 met selection criteria for aPCNL and were included. Primary outcome was safety and efficacy, and secondary outcome was to identify predictors of inpatient stay. Demographic and perioperative data were analyzed with both descriptive and inferential statistics. Results: In total, between 2016 and 2020, 552 patients underwent PCNL, with 175 of them meeting criteria for aPCNL. One hundred thirty-four of the 175 (76.6%) of these patients were discharged the same day as the surgery and 41 patients were admitted. On univariate analysis, patients who required upper pole access or multiple accesses (p = 0.038) American Society of Anesthesiologists >2 (p = 0.005), or postoperative nephrostomy (PCN) tube (p < 0.001) were more likely to be admitted after surgery. On multivariate analysis, only postoperative PCN was significantly associated with admission (p = 0.015). Regarding reasons for unsuccessful aPCNL, 19.5% of admissions were attributed to intraoperative complications, 7% to social causes, 12.2% to postoperative complications, 14.6% to uncontrolled pain, and 34.1% to unexpected intraoperative procedures. Conclusions: aPCNL using selection criteria is safe and effective, with postoperative PCN predicting the possible necessity for conversion to inpatient admission. Furthermore, our study provides a practical algorithm for those opting to provide aPCNL to patients.

Standardizing Perioperative Medications to Be Used in an Enhanced Recovery After Surgery Program Is Feasible in Percutaneous Nephrolithotomy Patients.

Introduction: The objective of this process improvement project was to determine the effect of enhanced recovery after surgery (ERAS) protocol for percutaneous nephrolithotomy (PCNL) patients with respect to quality of life (QOL) and pain management in the postoperative recovery period. Methods: An electronic-based medical record ERAS orders protocol for PCNL was instituted at an academic medical center in July 2020. The protocol utilized a pain control regimen designed to minimize opioid medication use postoperatively. We prospectively evaluated PCNL patients' QOL through the Wisconsin Stone Quality of Life (WISQOL) survey and Patient-Reported Outcomes Measurement System (PROMIS) at routine perioperative visits. To assess any opioid reduction benefit of the ERAS protocol, we reviewed an age-matched historical cohort n = 66 (before ERAS implementation) to serve as a comparison cohort with respect to opioid usage. Results: After an inception cohort of 95 patients, 55 ERAS patients remained available for assessment with the WISQOL and PROMIS surveys. In comparison with the non-ERAS cohort, the ERAS cohort represented larger stones, more supine positioning, higher blood loss, shorter hospital stay, and more use of access sheath. ERAS patients received a significantly lower amount of opioids compared with non-ERAS patients upon discharge narcotic usage (116.13 morphine milliequivalent [MME] vs 39.57 MME, p = 0.0001). Compared with their preoperative evaluation, the ERAS cohort had significantly improved QOL scores at 1 week, which sustained through 8 weeks postoperatively. Moreover, pain intensity and pain interference scores were improved at 8 weeks postoperatively for ERAS patients compared with their preoperative time point. Conclusions: We demonstrate that standardizing medications in early efforts toward a PCNL ERAS protocol is feasible and allows for reduced opioid use by patients while achieving early and sustained postprocedure QOL.

Flexible Ureteroscopy for Treatment of Upper Urinary Tract Calculus.

The aim of this article is to illustrate a step-by-step guide to flexible ureteroscopy (URS) for treatment of upper urinary tract calculus. Preoperative evaluation of the patient with focus on comorbidities is paramount for the type of stone procedure to be performed. In this article, the steps of operating room setup, patient positioning, gaining access to the upper urinary tract, flexible URS, laser lithotripsy, basket extraction of stone fragments, and placement of a ureteral stent are described. The importance of clearance of the ureter before flexible URS in the case of pre-existing ureteral stone is also described.

Placement of Resonance Stent for Malignant or Benign Ureteral Obstruction.

The aim of this article is to illustrate a step-by-step guide to placement of Resonance® metallic ureteral stent (Cook Medical, Bloomington, IN) for management of malignant or benign ureteral obstruction. In this article, the steps of operating room setup, patient positioning, gaining access to the upper urinary tract, and endoscopic and fluoroscopic placement of a Resonance ureteral stent are described.

In Vitro Evaluation of Stone Fragment Evacuation by Suction.

Introduction: Contemporary, flexible stone baskets are unable to extract submillimeter stone fragments at the time of ureteroscopic laser lithotripsy. In this in vitro study, the feasibility of suctioning submillimeter fragments with a standard Luer Lock syringe through the working channel of a flexible ureteroscope was assessed. Materials and Methods: Phantom stones made from industrial plaster were mechanically fragmented into ≤1 and ≤0.5-mm groups. Both stone groups were divided into five preweighed trial samples. Each stone group was then mixed in a beaker filled with normal saline. A standard 10-mL Luer Lock syringe was connected to a fiber-optic ureteroscope with a 1.2-mm working channel. The syringe was then used to suction stone fragments from the beaker. The suctioned stone fragments and the stone fragments remaining in the beaker after removing the overlying solution were separated, centrifuged with supernatant removed, and dried in an incubator set at 33°C for 1 week. Dried weights were recorded. Results: Mean total weights for ≤0.5 and ≤1.0-mm stone groups at baseline were 0.807 and 0.806 g, respectively. The mean percentages of stone fragments suctioned through the ureteroscope for ≤0.5 and ≤1.0-mm groups were 86% and 86%, respectively (p = 0.973). During suctioning, 64% of stones in the ≤0.5-mm group were trapped in either the working channel of the ureteroscope or within the Luer Lock syringe compared with 78% of stones in the ≤1-mm group (p = 0.001) requiring cessation of the procedure to clear the channel. Conclusions: It is feasible to suction submillimeter stone fragments by connecting a Luer Lock syringe to the working channel of a flexible ureteroscope. The limiting factor for removing stone fragments appears to be the small working channel of flexible ureteroscopes as trapping of fragments during suctioning is common and requires time-consuming removal of the endoscope and clearing of the channel.

A Randomized Controlled Trial of Preoperative Prophylactic Antibiotics for Percutaneous Nephrolithotomy in Moderate to High Infectious Risk Population: A Report from the EDGE Consortium.

PURPOSE: Postoperative infectious related complications are not uncommon after percutaneous nephrolithotomy. Previously, we noted that 7 days of antibiotics did not decrease sepsis rates compared to just perioperative antibiotics in a low risk percutaneous nephrolithotomy population. This study aimed to compare the same regimens in individuals at moderate to high risk for sepsis undergoing percutaneous nephrolithotomy. MATERIALS AND METHODS: Patients were prospectively randomized in this multi-institutional study to either 2 days or 7 days of preoperative antibiotics. Enrolled patients had stones requiring percutaneous nephrolithotomy and had either a positive preoperative urine culture or existing indwelling urinary drainage tube. Primary outcome was difference in sepsis rates between the groups. Secondary outcomes included rate of nonseptic bacteriuria, stone-free rate and length of stay. RESULTS: A total of 123 patients at 7 institutions were analyzed. There was no difference in sepsis rates between groups on univariate analysis. Similarly, there were no differences in nonseptic bacteriuria, stone-free rate and length of stay. On multivariate analysis, 2 days of antibiotics increased the risk of sepsis compared to 7 days of antibiotics (OR 3.1, 95% CI 1.1-8.9, p=0.031). Patients receiving antibiotics for 2 days had higher rates of staghorn calculus than the 7-day group (58% vs 32%, p=0.006) but post hoc subanalysis did not demonstrate increased sepsis in the staghorn only group. CONCLUSIONS: Giving 7 days of preoperative antibiotics vs 2 days decreases the risk of sepsis in moderate to high risk percutaneous nephrolithotomy patients. Future guidelines should consider infectious risk stratification for percutaneous nephrolithotomy antibiotic recommendations.

Quarter Century Management of Chronic Ureteropelvic Junction Obstruction in a Solitary Kidney with a Ureteral Stent.

Background: The ureteral stent provides a conduit for urinary drainage from the kidney to the bladder and is integral to contemporary urologic practice. A ureteral stent is often utilized in acute conditions to prevent or overcome obstruction; however, in nonsurgical patients, because of disease or preference, a ureteral stent may be used as a last resort for long-term management of a stricture in lieu of a nephrostomy tube. This case highlights a patient whose chronic ureteral obstruction has been managed with an indwelling ureteral stent for 25 years; remarkably, stent exchanges are currently required only every 2 years. Case Presentation: A 33-year-old man initially presented with a solitary left kidney and a ureteropelvic junction obstruction. The patient's right kidney was nonfunctioning since childhood because of a presumed ureteropelvic junction obstruction with grade IV hydronephrosis. The patient underwent two failed open repairs of the left kidney in the 1980s, resulting in a totally intrarenal, constricted renal pelvis; an endopyelotomy in 1992 also failed and required angioembolizaton of a segmental renal vessel. The patient refused any further surgical procedures and thus has been managed exclusively with a 7/14F × 28 cm endopyelotomy stent (Boston Scientific®) for 25 years; the interval between stent changes was slowly expanded until they are now being done at 2-year intervals. The patient has not developed recurrent urinary tract infections, stent colic, or stent encrustation. Conclusion: Patients who require chronic indwelling ureteral stents are rare. In this situation, with careful monitoring, the interval between stent exchanges was extended to 2 years, thereby precluding a chronic nephrostomy tube.

Electronic health record problem lists: accurate enough for risk adjustment?

OBJECTIVES: To determine whether comorbidity information derived from electronic health record (EHR) problem lists is accurate. STUDY DESIGN: Retrospective cohort study of 1596 men diagnosed with prostate cancer between 1998 and 2004 at 2 Southern California Veterans Affairs Medical Centers with long-term follow-up. METHODS: We compared EHR problem list-based comorbidity assessment with manual review of EHR free-text notes in terms of sensitivity and specificity for identification of major comorbidities and Charlson Comorbidity Index (CCI) scores. We then compared EHR-based CCI scores with free-text-based CCI scores in prediction of long-term mortality. RESULTS: EHR problem list-based comorbidity assessment had poor sensitivity for detecting major comorbidities: myocardial infarction (8%), cerebrovascular disease (32%), diabetes (46%), chronic obstructive pulmonary disease (42%), peripheral vascular disease (31%), liver disease (1%), and congestive heart failure (23%). Specificity was above 94% for all comorbidities. Free-text-based CCI scores were predictive of long-term other-cause mortality, whereas EHR problem list-based scores were not. CONCLUSIONS: Inaccuracies in EHR problem list-based comorbidity data can lead to incorrect determinations of case mix. Such data should be validated prior to application to risk adjustment.

Predictors of Complications After Percutaneous Image-Guided Renal Cryoablation for T1a Renal Cortical Neoplasms.

PURPOSE: To determine the incidence and predictors of major complications in patients undergoing percutaneous cryoablation (PCA) for small renal masses. METHODS: We performed a retrospective analysis of patients undergoing PCA from 2005 to 2012. We analyzed demographic, radiographic, and complication data. We defined complications as any deviation from the expected postoperative course. We determined predictors of complications. RESULTS: A total of 190 patients were included in the study. The mean age was 69 years, and 132 (69%) were males. The mean tumor diameter was 2.2 cm (0.8-4.0 cm). The mean number of probes utilized per procedure was 2.3. We observed 16 (8.4%) complications including 14 Clavien grade I, which includes 6 (2%) large renal/retroperitoneal hematomas, 4 (2%) pneumothoraxes, 2 (1%) urinary tract infections, and 2 (1%) atrial fibrillations. There were two (1%) Clavien grade II complications (intestinal perforations). In univariable analysis, larger tumors and more probes were associated with higher risk of complications (all ps < 0.05). In multivariable analysis, larger tumor dimension (odds ratio [OR] = 2.85; 95% confidence interval [CI] = 1.34, 6.05; p = 0.006) was independently associated with major complications. After multivariable adjustments for patient's characteristics such as age, gender, American Society of Anesthesiologists, year of surgery, and histopathology, larger tumor dimension (OR = 2.85; 95%CI = 1.34, 6.05; p = 0.006) and more cryoablation probes (OR = 1.94; 95%CI = 1.36, 2.75; p < 0.001) were independently associated with higher risk of major complications. CONCLUSIONS: In a cohort of patients undergoing PCA for T1a small renal mass, larger tumor dimension and more cryoablation probes were independently associated with higher risk of complication. Although PCA is relatively safe and the major complications are infrequent, careful patient selection is crucial.

Comparison of Pneumoperitoneum Stability Between a Valveless Trocar System and Conventional Insufflation: A Prospective Randomized Trial.

OBJECTIVE: To compare the variation in pneumoperitoneum and physiologic effects of patients undergoing laparoscopic renal surgery using the valveless trocar insufflation system (VI) vs a conventional insufflation system (CI). METHODS AND MATERIALS: We conducted a single-center, randomized controlled trial in patients undergoing renal surgery at 15 mm Hg insufflation using a VI system vs a CI system. The primary outcome measured was variation in insufflation pressure, and end-tidal CO2 at 10 and 25 minutes. RESULTS: Fifty-six patients (VI n = 28 or CI n = 28) met inclusion criteria and were randomized. There was significantly less variability in pressure readings, as measured by coefficient of variation, during VI compared to CI (7.8% vs 15.6%, P < .001). There was significantly less time spent within the range with pressure readings ≥18 mm Hg (median 0.2% vs 16.5%, P < .001) and ≤12 mm Hg (median 1.7% vs 5.6%, P = .011) during VI compared to CI. Additionally, there was significantly less time spent with pressure readings in the "unacceptable" range of ≥20 mm Hg (median 0% vs 0.08%, P < .001) and ≤10 mm Hg (median 0.09% vs 2.6%, P < .001) during the cases with VI compared to CI. End-tidal CO2 was significantly lower at 10 minutes (P = .036) after insufflation in the valveless trocar group compared to the conventional treatment group. There were no other significant differences in physiologic metrics. CONCLUSION: Compared with a CI, the VI provides a significantly more stable pneumoperitoneum during laparoscopic renal surgery and lower end-tidal CO2 at 10 minutes.

Comparison of Flow Characteristics of Novel Three-Dimensional Printed Ureteral Stents Versus Standard Ureteral Stents in a Porcine Model.

PURPOSE: We compared the flow characteristics of novel three-dimensional (3D) printed ureteral stents with four conventional double-pigtail stents in an ex vivo porcine model. MATERIALS AND METHODS: In six ex vivo porcine urinary systems with kidneys and ureters intact, we deployed a 5F occlusion catheter in an interpolar calix. We tested each system with antegrade irrigation with a 0.9% saline bag placed 35 cm above the renal pelvis. We evaluated four standard stents (6F Universa® Soft, 7F Percuflex,™ 7/10F Applied Endopyelotomy, 8.5F Filiform Double Pigtail) and compared them with a 9F 3D printed prototype stent. For each stent, we measured the total, extraluminal, and intraluminal flow rates. RESULTS: The mean total flow rates for 3D printed stents were significantly higher than the 6F, 7F, and 7/10F stents (P<0.05). No significant difference was seen in the total flow rate for the 3D printed stent and the 8.5F stent. The mean extraluminal flow rates for the 3D stents were similar to those of 7F stents, but significantly lower than 6F stents (P<0.001) and 8.5F stents (P<0.05) and higher than 7/10F stents (P<0.001). The mean intraluminal flow rates for the 3D printed stents were significantly higher than the 6F, 7F, 7/10F, and 8.5F stents (P<0.05). CONCLUSIONS: In this pilot study, 3D printed stents manifested a mean total flow rate comparable to the flow rates of contemporary stents. Continued advances in technology and material may permit functionally feasible 3D printed ureteral stents.

Redefining the Autonomic Nerve Distribution of the Bladder Using 3-Dimensional Image Reconstruction.

PURPOSE: We sought to create a 3-dimensional reconstruction of the autonomic nervous tissue innervating the bladder using male and female cadaver histopathology. MATERIALS AND METHODS: We obtained bladder tissue from a male and a female cadaver. Axial cross sections of the bladder were generated at 3 to 5 mm intervals and stained with S100 protein. We recorded the distance between autonomic nerves and bladder mucosa. We manually demarcated nerve tracings using ImageScope software (Aperio, Vista, California), which we imported into Blender™ graphics software to generate 3-dimensional reconstructions of autonomic nerve anatomy. RESULTS: Mean nerve density ranged from 0.099 to 0.602 and 0.012 to 0.383 nerves per mm2 in female and male slides, respectively. The highest concentrations of autonomic innervation were located in the posterior aspect of the bladder neck in the female specimen and in the posterior region of the prostatic urethra in the male specimen. Nerve density at all levels of the proximal urethra and bladder neck was significantly higher in posterior vs anterior regions in female specimens (0.957 vs 0.169 nerves per mm2, p<0.001) and male specimens (0.509 vs 0.206 nerves per mm2, p=0.04). CONCLUSIONS: Novel 3-dimensional reconstruction of the bladder is feasible and may help redefine our understanding of human bladder innervation. Autonomic innervation of the bladder is highly focused in the posterior aspect of the proximal urethra and bladder neck in male and female bladders.

Development and initial porcine and cadaver experience with three-dimensional printing of endoscopic and laparoscopic equipment.

INTRODUCTION: Recent advances in three-dimensional (3D) printing technology have made it possible to print surgical devices. We report our initial experience with the printing and deployment of endoscopic and laparoscopic equipment. MATERIALS AND METHODS: We created computer-aided designs for ureteral stents and laparoscopic trocars using SolidWorks. We developed three generations of stents, which were printed with an Objet500 Connex printer, and a fourth generation was printed with an EOSINT P395 printer. The trocars were printed with an Objet30 Pro printer. We deployed the printed stents and trocars in a female cadaver and in vivo porcine model. We compared the printed trocars to two standard trocars for defect area and length using a digital caliper. Paired T-tests and ANOVA were used to test for statistical difference. RESULTS: The first two generations of stents (7F and 9F) were functional failures as their diminutive inner lumen failed to allow the passage of a 0.035 guidewire. The third generation 12F stent allowed passage of a 0.035 guidewire. The 12F diameter limited its deployment, but it was introduced in a cadaver through a ureteral access sheath. The fourth-generation 9F stents were printed and deployed in a porcine model using the standard Seldinger technique. The printed trocars were functional for the maintenance of the pneumoperitoneum and instrument passage. The printed trocars had larger superficial defect areas (p<0.001) and lengths (p=0.001) compared to Karl Storz and Ethicon trocars (29.41, 18.06, and 17.22 mm(2), respectively, and 14.29, 11.39, and 12.15 mm, respectively). CONCLUSIONS: In this pilot study, 3D printing of ureteral stents and trocars is feasible, and these devices can be deployed in the porcine and cadaver models. Three-dimensional printing is rapidly advancing and may be clinically viable in the future.

Comparison of radiation dose from conventional and triple-bolus computed tomography urography protocols in the diagnosis and management of patients with renal cortical neoplasms.

OBJECTIVE: To retrospectively compare the radiation dose of triple-bolus computed tomography (TBCT) and conventional CT (CCT) urography protocols, analyze the effects of body mass index (BMI) on radiation dose in each group, and assess image quality. MATERIALS AND METHODS: We retrospectively reviewed the images of patients who underwent CCT or TBCT imaging in the management of renal cortical neoplasms. We used standard volumetric CT dose index (CTDIvol) and dose length product (DLP) to estimate radiation exposure. In addition, 2 urologists rated the quality of 20 CT images from each group using a survey with a 5-point Likert scale. The survey consisted of 10 questions relating to the ability of the scan to identify relevant renal anatomy. RESULTS: The study included 120 patients. CTDIvol and DLP were 28.7% and 40.4% lower in the TBCT protocol, respectively (both P < .001). Increased BMI was associated with a higher DLP for the CCT group compared with the TBCT group (P < .001). The effect of BMI on CTDIvol did not differ between the CCT and TBCT groups. There was no difference in the urologists' assessments of CT image quality. CONCLUSION: In patients with renal cortical neoplasms, TBCT provides comparable image quality to CCT, with lower ionizing radiation exposure without compromising image quality. Obese patients may benefit more from TBCT scans.

Paradoxical visuomotor adaptation to reversed visual input is predicted by BDNF Val66Met polymorphism.

Brain-derived neurotrophic factor (BDNF) is the most abundant neurotrophin in the brain, influencing neural development, plasticity, and repair (Chen et al., 2004; Thoenen, 1995). The BDNF gene contains a single-nucleotide polymorphism (SNP) called Val(66)Met. The Met allele interferes with intracellular BDNF-trafficking, decreases activity-dependent BDNF secretion, and consequently is often associated with a shift from plasticity to stability in neural circuits (Egan et al., 2003). We investigated the behavioral consequences of the presence of the Met allele by comparing how 40 heterozygous subjects with the Val/Met genotype and 35 homozygous subjects with the Val/Val genotype performed on visuomotor tasks (reaching and navigation) under two conditions: normal vision and completely left-right reversed vision. As expected, subjects did not differ in their short-term ability to learn the tasks with normal vision (p = 0.58). Intuitively, it would be expected that homozygous Val/Val subjects with a propensity for greater BDNF-induced activity-dependent plasticity would learn new tasks more quickly than heterozygous Val/Met subjects with decreased BDNF secretion (Gilbert, Li, & Piech, 2009). However, we found the opposite here. When short-term mechanisms of visuomotor adaptation were engaged to compensate for the misalignment of visual and somatomotor information created by the left-right reversal of vision, heterozygous Val/Met subjects learned significantly more quickly than their homozygous Val/Val counterparts (p = 0.027). Our results demonstrate the paradoxical finding that the presence of the Met allele, which is thought to promote cortical stability, here improves immediate visuomotor adaptation to left-right-reversed visual input.