Gregory E. Tasian

Diagnostic Performance of Ultrasound in Nonpalpable Cryptorchidism: A Systematic Review and Meta-analysis

CONTEXT: Ultrasound is frequently obtained during the presurgical evaluation of boys with nonpalpable undescended testes, but its clinical utility is uncertain. OBJECTIVE: To determine the diagnostic performance of ultrasound in localizing nonpalpable testes in pediatric patients. METHODS: English-language articles were identified by searching Medline, Embase, and the Cochrane Library. We included studies of subjects younger than 18 years who had preoperative ultrasound evaluation for nonpalpable testes and whose testis position was determined by surgery. Data on testis location determined by ultrasound and surgery were extracted by 2 independent reviewers, from which ultrasound performance characteristics (true-positives, false-positives, false-negatives, and true-negatives) were derived. Meta-analysis of 12 studies (591 testes) was performed by using a random-effects regression model; composite estimates of sensitivity, specificity, and likelihood ratios were calculated. RESULTS: Ultrasound has a sensitivity of 45% (95% confidence interval [CI]: 29–61) and a specificity of 78% (95% CI: 43–94). The positive and negative likelihood ratios are 1.48 (95% CI: 0.54–4.03) and 0.79 (95% CI: 0.46–1.35), respectively. A positive ultrasound result increases and negative ultrasound result decreases the probability that a nonpalpable testis is located within the abdomen from 55% to 64% and 49%, respectively. Significant heterogeneity limited the precision of these estimates, which was attributable to variability in the reporting of selection criteria, ultrasound methodology, and differences in the proportion of intraabdominal testes. CONCLUSIONS: Ultrasound does not reliably localize nonpalpable testes and does not rule out an intraabdominal testis. Eliminating the use of ultrasound will not change management of nonpalpable cryptorchidism but will decrease health care expenditures.

Age at Orchiopexy and Testis Palpability Predict Germ and Leydig Cell Loss: Clinical Predictors of Adverse Histological Features of Cryptorchidism

PURPOSE We determined the relationship between clinical variables and testicular histopathological changes associated with decreased fertility potential in children with cryptorchidism. MATERIALS AND METHODS Testis biopsies of 274 children who underwent orchiopexy and concurrent testicular biopsy between 1991 and 2001 were analyzed for germ and Leydig cell loss, and testicular fibrosis. Multivariable logistic regression was used to determine if age at orchiopexy (analyzed as continuous and ordinal variables), preoperative testis palpability, unilateral vs bilateral disease and/or side of undescended testis was predictive of these pathological outcomes. RESULTS Age at orchiopexy was associated with germ and Leydig cell depletion. Each month of testis undescent was associated with development of moderate/severe germ cell depletion (OR 1.02 for each month of age, p <0.005) and Leydig cell loss (OR 1.01 for each month of age, p <0.02). Nonpalpable testes were associated with severe germ cell depletion. Children with palpable testes had lower odds of germ cell depletion than those with nonpalpable testes (OR 0.46, p <0.005). This finding corresponds to a significant 2% risk per month of severe germ cell loss and 1% risk per month of Leydig cell depletion for each month a testis remains undescended, and a 50% greater risk of germ cell depletion in nonpalpable relative to palpable cryptorchid testes. CONCLUSIONS Testes that remain undescended are associated with progressive loss of germ and Leydig cells, and nonpalpable testes predict severe germ cell loss.

Caucasian male infants and boys with hypospadias exhibit reduced anogenital distance

BACKGROUND Animal models of endocrine dysfunction have associated male genital defects with reduced anogenital distance (AGD). Human studies have correlated shorter AGD with exposure to putative endocrine disruptors in the environment but have not examined AGD in hypospadiac boys. We measured AGD in boys with hypospadias and those with normal genitals. METHODS Data were collected prospectively on boys undergoing urologic procedures at the University of California San Francisco and the Childrens Hospital of Oakland, CA, USA. Data included age, race, height, weight, BMI, urologic diagnoses and AGD. To minimize any potential effects of race on observed AGD, we examined only Caucasian boys. Differences between boys with hypospadias and those with normal genitals were examined through two-tailed Students t-tests. RESULTS One hundred and nineteen Caucasian boys ranging in age from 4 to 86 months underwent AGD measurement, of which 42 and 77 were boys with normal genitals and hypospadias, respectively. The mean (±SD) AGD of boys with hypospadias was 67 ± 1.2 versus 73 ± 1 mm for boys with normal genitals (P = 0.002). In these age-unmatched patient groups, there were also differences in age, height and weight (P = 0.0001, 0.0002 and 0.0004, respectively). After age matching (all <2 years of age), boys with hypospadias (n= 26) still featured a shorter AGD than boys with normal genitals (n= 26; 62 ± 2 versus 68 ± 2 mm respectively, P = 0.033) but the differences in age, height and weight were no longer significant. CONCLUSIONS In humans, hypospadias may indeed be associated with reduced AGD. Additional studies are needed to corroborate these preliminary findings and to determine their etiology.

Diagnostic Imaging in Cryptorchidism: Utility, Indications, and Effectiveness

BACKGROUND Cryptorchidism (undescended testis) is the most common genitourinary anomaly in male infants. METHODS We reviewed the available literature on the diagnostic performance of ultrasound, computed tomography, and magnetic resonance imaging (MRI) in localizing undescended testes. RESULTS Ultrasound is the most heavily used imaging modality to evaluate undescended testes. Ultrasound has variable ability to detect palpable testes and has an estimated sensitivity and specificity of 45% and 78%, respectively, to accurately localize nonpalpable testes. Given the poor ability to localize nonpalpable testes, ultrasound has no role in the routine evaluation of boys with cryptorchidism. Magnetic resonance imaging has greater sensitivity and specificity but is expensive, not universally available, and often requires sedation for effective studies of pediatric patients. Diagnostic laparoscopy has nearly 100% sensitivity and specificity for localizing nonpalpable testes and allows for concurrent surgical correction. CONCLUSIONS Although diagnostic imaging does not have a role in the routine evaluation of boys with cryptorchidism, there are clinical scenarios in which imaging is necessary. Children with ambiguous genitalia or hypospadias and undescended testes should have ultrasound evaluation to detect the presence of müllerian structures.

Annual Incidence of Nephrolithiasis among Children and Adults in South Carolina from 1997 to 2012

BACKGROUND AND OBJECTIVES The prevalence of nephrolithiasis in the United States has increased substantially, but recent changes in incidence with respect to age, sex, and race are not well characterized. This study examined temporal trends in the annual incidence and cumulative risk of nephrolithiasis among children and adults living in South Carolina over a 16-year period. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS We performed a population-based, repeated cross-sectional study using the US Census and South Carolina Medical Encounter data, which capture all emergency department visits, surgeries, and admissions in the state. The annual incidence of nephrolithiasis in South Carolina from 1997 to 2012 was estimated, and linear mixed models were used to estimate incidence rate ratios for age, sex, and racial groups. The cumulative risk of nephrolithiasis during childhood and over the lifetime was estimated for males and females in 1997 and 2012. RESULTS Among an at-risk population of 4,625,364 people, 152,925 unique patients received emergency, inpatient, or surgical care for nephrolithiasis. Between 1997 and 2012, the mean annual incidence of nephrolithiasis increased 1% annually from 206 to 239 per 100,000 persons. Among age groups, the greatest increase was observed among 15-19 year olds, in whom incidence increased 26% per 5 years (incidence rate ratio, 1.26; 95% confidence interval, 1.22 to 1.29). Adjusting for age and race, incidence increased 15% per 5 years among females (incidence rate ratio, 1.15; 95% confidence interval, 1.14 to 1.16) but remained stable for males. The incidence among blacks increased 15% more per 5 years compared with whites (incidence rate ratio, 1.15; 95% confidence interval, 1.14 to 1.17). These changes in incidence resulted in doubling of the risk of nephrolithiasis during childhood and a 45% increase in the lifetime risk of nephrolithiasis for women over the study period. CONCLUSIONS The incidence of kidney stones has increased among young patients, particularly women, and blacks.

Learning Curve of Robotic Assisted Pyeloplasty for Pediatric Urology Fellows

PURPOSE Little is known about the learning curve of robotic surgery for surgeons in training. We hypothesized that pediatric urology fellows could attain proficiency in robotic pyeloplasty, defined as operative time equivalent to that of an experienced robotic surgeon, within the 2-year time frame of fellowship. MATERIALS AND METHODS From 2006 to 2010 we performed a prospective cohort study of pediatric robotic pyeloplasty done by 4 pediatric urology fellows and 1 pediatric urology attending surgeon. We recorded operative times and surgical outcomes of the total of 20 consecutive robotic pyeloplasties performed by the 4 pediatric urology fellows (80 cases) and a random sample of 20 performed by the attending surgeon. Multivariate linear regression was used to determine the change in operative time for each case done by fellows and estimate the number of cases needed for fellows to achieve the median operative time of the attending pediatric urologist. RESULTS Fellow operative time decreased at a constant average rate of 3.7 minutes per case (95% CI 3.0-4.3). Fellows were projected to achieve the median operative time of the attending surgeon after 37 cases. No operative complications or failed pyeloplasties occurred. CONCLUSIONS The operative time for robotic pyeloplasty performed by fellows consistently decreased with cumulative surgical experience. These data can be used to help establish benchmarks of robotic pyeloplasty for pediatric urology, assuming appropriate exposure to robotics and adequate case volume.

Risk of Fracture in Urolithiasis: A Population-Based Cohort Study Using the Health Improvement Network

BACKGROUND AND OBJECTIVES Studies have shown decreased bone mineral density in individuals with urolithiasis, but their burden of fracture remains unclear. This study sought to determine whether urolithiasis is associated with increased fracture risk across the lifespan and to delineate sex effects. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS A population-based retrospective cohort study using The Health Improvement Network was performed. The median calendar year for the start of the observation period was 2004 (1994-2012). This study identified 51,785 participants with ≥1 of 87 diagnostic codes for urolithiasis and 517,267 randomly selected age-, sex-, and practice-matched participants. Cox regression was used to estimate the hazard ratio (HR) for first fracture. Fractures identified using diagnostic codes were classified by anatomic site. RESULTS Median age was 53 years, and 67% of participants were men, confirming their greater urolithiasis burden. Median time from urolithiasis diagnosis to fracture was 10 years. The HR for fracture associated with urolithiasis differed by sex and age (P for interactions, P≤0.003). In men, the adjusted HR was greatest in adolescence (1.55; 95% confidence interval [95% CI], 1.07 to 2.25) with an overall HR of 1.10 (95% CI, 1.05 to 1.16). Urolithiasis was associated with higher fracture risk in women aged 30-79 years (HR, 1.17-1.52), and was highest in women aged 30-39 years (HR, 1.52; 95% CI, 1.23 to 1.87). Peak background fracture rates were highest in boys aged 10-19 years and in women aged 70-79 years. The incidence per 10,000 person-years in participants with versus without urolithiasis was 392 versus 258 in male participants aged 10-19 years, and 263 versus 218 in women aged 70-79 years. Distribution of fracture site within sex did not differ between participants with versus without urolithiasis. CONCLUSIONS Urolithiasis was associated with higher incident fracture risk. The significantly higher risk at times of peak background fracture incidence in adolescent boys and elderly women has profound public health implications.

Pubic Hair Grooming Injuries Presenting to U.S. Emergency Departments

OBJECTIVE To describe the demographics and mechanism of genitourinary (GU) injuries related to pubic hair grooming in patients who present to U.S. emergency departments (EDs). MATERIALS AND METHODS The National Electronic Injury Surveillance System contains prospectively collected data from patients who present to EDs with consumer product-related injuries. The National Electronic Injury Surveillance System is a stratified probability sample, validated to provide national estimates of all patients who present to U.S. EDs with an injury. We reviewed the National Electronic Injury Surveillance System to identify incidents of GU injury related to pubic hair grooming for 2002-2010. The variables reviewed included age, race, gender, injury type, location (organ) of injury, hospital disposition, and grooming product. RESULTS From 2002 to 2010, an observed 335 actual ED visits for GU injury related to grooming products provided an estimated 11,704 incidents (95% confidence interval 8430-15,004). The number of incidents increased fivefold during that period, amounting to an estimated increase of 247 incidents annually (95% confidence interval 110-384, P = .001). Of the cohort, 56.7% were women. The mean age was 30.8 years (95% confidence interval 28.8-32.9). Shaving razors were implicated in 83% of the injuries. Laceration was the most common type of injury (36.6%). The most common site of injury was the external female genitalia (36.0%). Most injuries (97.3%) were treated within the ED, with subsequent patient discharge. CONCLUSION Most GU injuries that result from the use of grooming products are minor and involve the use of razors. The demographics of patients with GU injuries from grooming products largely paralleled observations about cultural grooming trends in the United States.

Evaluation of Renal Function After Major Renal Injury: Correlation With the American Association for the Surgery of Trauma Injury Scale

PURPOSE In this study we evaluated the effect of major kidney injury on renal function. MATERIALS AND METHODS A retrospective cross-sectional analysis was conducted of all patients who sustained renal trauma between 1977 and 2008 at San Francisco General Hospital, and underwent post-injury dimercapto-succinic acid renal scan (67). Decrease in renal function was defined as the absolute percentage difference between the affected and unaffected kidney on dimercapto-succinic acid scan. Univariate (Spearman rank correlation) and multivariate (linear regression) analyses of the American Association for the Surgery of Trauma renal injury grade, patient age, mechanism of injury (blunt vs penetrating), side of injury, treatment used (nonoperative vs surgery), shock, gender, presence of gross hematuria, serum creatinine on hospital admission, postoperative complications and associated injuries were performed. RESULTS Of the 67 renal injuries 23 (34%) were managed nonoperatively. There were 43 (64%) injuries due to penetrating trauma and 24 (36%) due to blunt injury. Mean decrease in renal function for grade III, IV and V injuries was 15%, 30% and 65%, respectively. Univariate analysis demonstrated a significant association between decrease in renal function and injury grade (rho 0.43, p <0.005). There was no difference in the decrease in kidney function between parenchymal and vascular causes for grade IV and V injuries. Although the right kidney demonstrated a greater decrease in function (rho 0.26, p = 0.033) on univariate analysis, multivariate analysis showed that only American Association for the Surgery of Trauma injury grade correlated with decreased function (correlation coefficient 14.3, 95% CI 4.7-24.8, p <0.005). CONCLUSIONS Decrease in kidney function is directly correlated with American Association for the Surgery of Trauma renal injury grade.

Tamsulosin and Spontaneous Passage of Ureteral Stones in Children: A Multi-Institutional Cohort Study

PURPOSE Tamsulosin is associated with increased passage of ureteral stones in adults but its effectiveness in children is uncertain. We determined the association between tamsulosin and the spontaneous passage of ureteral stones in children. MATERIALS AND METHODS We performed a multi-institutional retrospective cohort study of patients 18 years or younger who presented between 2007 and 2012 with ureteral stones up to 10 mm and who were treated with tamsulosin or oral analgesics alone. The outcome was spontaneous stone passage, defined as radiographic clearance and/or patient report of passage. Subjects prescribed tamsulosin were matched with subjects prescribed analgesics alone, using nearest neighbor propensity score matching to adjust for treatment selection. Conditional logistic regression models were used to estimate the association between tamsulosin and spontaneous passage of ureteral stones, adjusting for stone size and location. RESULTS Of 449 children with ureteral stones 334 were eligible for inclusion, and complete data were available for 274 patients from 4 institutions (99 receiving tamsulosin, 175 receiving analgesics alone). Following case matching, there were no differences in age, gender, weight, height, stone size or stone location between the 99 subjects prescribed tamsulosin and the 99 propensity score matched subjects prescribed analgesics alone. In the tamsulosin cohort 55% of ureteral stones passed, compared to 44% in the analgesics alone cohort (p=0.03). In multivariate analysis adjusting for stone size and location tamsulosin was associated with spontaneous passage of ureteral stones (OR 3.31, 95% CI 1.49-7.34). CONCLUSIONS The odds of spontaneous passage of ureteral stones were greater in children prescribed tamsulosin vs analgesics alone.