Application of intraoperative structured light scanning to enable post-operative evaluation of digital and 3D-printed penile models.

BACKGROUND: Penile phenotype in hypospadias is currently assessed visually or manually (e.g., ruler, goniometer) for clinical, education, and research applications. However, these methods lack precision and accuracy across raters and cannot be reevaluated retrospectively following a surgical repair. The project aim was to evaluate the precision and reliability of penile dimensions obtained from digital and three dimensional (3D) printed models created from intraoperative (OR) structured light scans (SLS) during primary pediatric penile procedures. METHODS: Boys ages 1 month to 6 years underwent first- or single-stage penile surgery at a single institution were enrolled in this prospective study (IRB #20-000143). For each patient, immediately following placement of a stay suture under consistent manual tension, intra-operative dimension measurements with a ruler were obtained. A digital 3D model was created prior to penile repositioning using an Artec Space Spider scanner and Artec Studio 13 software. Following the case, two different raters completed 10 digital measurements of each generated model in Autodesk Fusion 360. These digital models were subsequently 3D printed and two different raters completed 10 manual dimension measurements of each 3D printed model using a ruler. A one-way random effects intraclass correlation coefficient (ICC) evaluated measures of agreement between and within raters, respectively. Analyses were conducted in R version 4.2. RESULTS: Six scans were obtained (hypospadias: 4, circumcision: 2). Intra-rater assessments showed excellent precision across repeated digital measurements; manual measurements of 3D printed models had excellent reliability for glans width and penile length but poor to good reliability for glans height. Inter-rater reliability was good to excellent for glans width (0.77-0.95) and good for penile length (0.71-0.88). However, there was poor inter-rater reliability for glans height (0-0.14). Following training regarding glans height location, there was an improvement in precision and repeatability of manual and digital measurements. CONCLUSION: Digital measurement of OR-derived 3D models resulted in excellent repeatability for each rater and improved between-rater reliability over manual measurement of 3D printed models alone, ensuring that images can be compared by various surgeons both now and in the future. SLS is promising as a novel modality to digitally generate 3D models, thereby informing phenotypic analysis for research and education. Further development of digital measurement methods to ensure consistency between raters for quantitative assessment of additional parameters and assessment of the technology within the pre-operative environment for surgical planning is planned.

Identifying variability in surgical practices and instrumentation for hypospadias repair across the Western Pediatric Urology Consortium (WPUC) network.

BACKGROUND: Although hypospadias outcomes studies typically report a level or type of repair performed, these studies often lack applicability to each surgical practice due to technical variability that is not fully delineated. An example is the tubularized incised plate (TIP) urethroplasty procedure, for which modifications have been associated with significantly decreased complication rates in single center series. However, many studies fail to report specificity in techniques utilized, thereby limiting comparison between series. OBJECTIVE: With the goal of developing a surgical atlas of hypospadias repair techniques, this study examined 1) current techniques used by surgeons in our network for recording operative notes and 2) operative technical details by surgeon for two common procedures, tubularized incised plate (TIP) distal and proximal hypospadias repairs across a multi-institutional surgical network. STUDY DESIGN: A two-part study was completed. First, a survey was distributed to the network to assess surgeon volume and methods of recording hypospadias repair operative notes. Subsequently, an operative template or a representative de-identified operative note describing a TIP and/or proximal repair with urethroplasty was obtained from participating surgeons. Each was analyzed by at least two individuals for natural language that signified specified portions of the procedure. Procedural details from each note were tabulated and confirmed with each surgeon, clarifying that the recorded findings reflected their current practice techniques and instrumentation. RESULTS: Twenty-five surgeons from 12 institutions completed the survey. The number of primary distal hypospadias repairs performed per surgeon in the past year ranged from 1-10 to >50, with 40% performing 1-20. Primary proximal hypospadias repairs performed in the past year ranged from 1-30, with 60% performing 1-10. 96% of surgeons maintain operative notes within an electronic health record. Of these, 66.7% edited a template as their primary method of note entry; 76.5% of these surgeons reported that the template captures their operative techniques very or moderately well. Operative notes or templates from 16 surgeons at 10 institutions were analyzed. In 7 proximal and 14 distal repairs, parameters for chordee correction, urethroplasty suture selection and technique, tissue utilized, and catheter selection varied widely across surgeons. CONCLUSION: Wide variability in technical surgical details of categorically similar hypospadias repairs was demonstrated across a large surgical network. Surgeon-specific modifications of commonly described procedures are common, and further evaluation of short- and long-term outcomes accounting for these technical variations is needed to determine their relative influence.

Novel Bacterial Topoisomerase Inhibitor Gepotidacin Demonstrates Absence of Fluoroquinolone-Like Arthropathy in Juvenile Rats.

Fluoroquinolone use in children is limited due to its potential toxicity and negative effects on skeletal development, but the actual effects/risks of fluoroquinolones on bone growth and the mechanisms behind fluoroquinolone-driven arthropathy remain unknown. Gepotidacin is a novel, bactericidal, first-in-class triazaacenaphthylene antibiotic with a unique mechanism of action that is not anticipated to have the same risks to bone growth as those of fluoroquinolones. Gepotidacin is in phase III clinical development for uncomplicated urinary tract infections (ClinicalTrials.gov identifiers NCT04020341 and NCT04187144) and urogenital gonorrhea (ClinicalTrials.gov identifier NCT04010539) in adults and adolescents ≥12 years of age. To inform arthropathy and other potential toxicity risks of gepotidacin in pediatric studies, this nonclinical study assessed oral gepotidacin toxicity in juvenile rats from postnatal day (PND) 4 to PND 32/35 (approximately equivalent to human ages from newborn to 11 years), using both in-life assessments (tolerability, toxicity, and toxicokinetics) and terminal assessments (necropsy with macroscopic and microscopic skeletal femoral head and/or stifle joint examinations). Gepotidacin doses of ≤300 mg/kg of body weight/day were well tolerated from PND 4 to PND 21, and higher doses of ≤1,250 mg/kg/day were well tolerated from PND 22 when the dose levels were escalated to maintain systemic exposure levels up to PND 35, with no observed treatment-related clinical signs, effects on mean body weight gain, or macroscopic findings on articular surfaces. A dose of 1,000 mg/kg/day was not tolerated during the dosing period from PND 4 to 21, with effects on body weight gain, fecal consistency, and body condition. Microscopic effects on articular surfaces were evaluated after 32 days of gepotidacin treatment at the highest tolerated dose. After 32 days of treatment with the highest tolerated gepotidacin dose of 300/1,250 mg/kg/day (systemic concentrations [area under the curve {AUC} values] of 93.7 µg · h/mL [males] and 121 µg · h/mL [females]), no skeletal effects on articular surfaces of the femoral head or stifle joint were observed. The absence of treatment-related clinical signs and arthropathy in juvenile rats provides evidence to support the potential future use of gepotidacin in children.

US research needs related to fatigue, sleep, and working hours among oil and gas extraction workers.

BACKGROUND: During 2003-2013, 1189 US oil and gas extraction (OGE) workers died while working, resulting in an average annual workplace fatality rate seven times that for all US workers. OGE work commonly involves long hours, shiftwork, irregular schedules, and long commutes, but effects of these factors on fatigue, occupational injury, and illness in OGE are largely unknown. METHODS: A scoping review of relevant OGE research during 2000-2019 was completed and supplemented by input from a NIOSH-sponsored Forum. RESULTS: Seventy-eight papers were identified; 76% reported only offshore research. Five themes for research needs emerged: build knowledge about the impacts of fatigue; explore interactions between on- and off-the-job risk factors; identify and evaluate interventions; assess effectiveness of technology; and increase the diffusion of fatigue risk management information. CONCLUSIONS: Further collaboration between researchers and OGE operators and contractors can lead to action-oriented recommendations to mitigate the effects of fatigue, inadequate sleep, and shiftwork.

Perceived Impact of Urologic Surgery Training Program Modifications due to COVID-19 in the United States.

OBJECTIVE: To assess urology residency program modifications in the context of COVID-19, and perceptions of the impact on urology trainees. METHODS: A cross-sectional survey of program leadership and residents at accredited US urology residencies was administered between April 28, 2020 to March 11, 2020. Total cohort responses are reported, and subanalyses were preformed comparing responses between those in in high vs low COVID-19 geographic regions, and between program leaders vs residents. RESULTS: Program leaders from 43% of programs and residents from 18% of programs responded. Respondents reported decreased surgical volume (83%-100% varying by subspecialty), increased use of telehealth (99%), a transition to virtual educational platforms (95%) and decreased size of inpatient resident teams (90%). Most residents are participating in care of COVID-19 patients (83%) and 20% endorsed that urology residents have been re-deployed. Seventy nine percent of respondents perceive a negative impact of recent events on urology surgery training and anxiety regarding competency upon completion of residency training was more pronounced among respondents in high COVID-19 regions. CONCLUSION: Major modifications to urology training programs were implemented in response to COVID-19. Attention must be paid to the downstream effects of the training disruption on urology residents.

Use of the Psychomotor Vigilance Test in Fitness for Work Assessments.

OBJECTIVE: The objective of the pilot program was to evaluate the utility of the psychomotor vigilance test (PVT) in aiding clinicians in making fitness for work determinations. METHODS: A 10-minute PVT was incorporated into fitness for work examinations by occupational health staff at two integrated refining/petrochemical plants. Based on all evidence from the clinical examination, including PVT results, clinicians made their fitness for work determination. RESULTS: Employees who were determined to be fit for work had significantly fewer PVT errors than did employees determined to be unfit for work or fit for work with limitations, with t(98) = -14.71, P < 0.001. CONCLUSIONS: The pilot assessed a new application of the PVT as an adjunct to occupational health evaluations focused on determining fitness for work. Results demonstrated that the PVT can be a valuable tool for this purpose.

Variations in payment patterns for surgical care in the centers for Medicare and Medicaid Services.

BACKGROUND: We investigated provider and regional variation in payments made to surgeons by the Centers for Medicare & Medicaid Services (CMS) by indexing payments to unique beneficiaries treated and examined the proportion of charges that resulted in payments. Understanding variation in care within CMS may prove actionable by identifying modifiable, and potentially unwarranted, variations. METHODS: We analyzed the Medicare Part B Provider Utilization and Payment Data released by CMS for 2012. We included Medicare B participants in the fee-for-service program. We calculated for each provider the ratio of number of services provided to individual beneficiaries, and the ratio of total submitted charges to total Medicare payments. We also categorized each provider into deciles of total Medicare payments, and calculated the means per decile of total Medicare payment for surgeons and urologists. To determine any associations with ratio of services to beneficiaries, we conducted multivariate linear regressions. RESULTS: The 20th, 40th, 60th, and 80th percentiles for the services-per-beneficiary ratios are 1.6, 2.2, 3.1, and 5.0, respectively (n = 83,376). Greater-earning surgeons offered more services per beneficiary, with a precipitous increase from the lowest decile to the highest. Charges were consistently greater than payments by a factor of 3. In our multivariate analysis of services per beneficiary ratio, female providers had lower ratios (P < .01), and we noted significant regional variation in the ratio of services per unique beneficiary (P < .001 for each of the 10 Standard Federal Regions). CONCLUSION: We found significant variation in patterns of payments for surgical care in CMS.

Engaging Physician Learners Through a Web-Based Platform: Individualized End-of-Life Education.

BACKGROUND: Web-based modules provide a convenient and low-cost education platform, yet should be carefully designed to ensure that learners are actively engaged. In order to improve attitudes and knowledge in end-of-life (EOL) care, we developed a web-based educational module that employed hyperlinks to allow users access to auxiliary resources: clinical guidelines and seminal research papers. METHODS: Participants took pre-test evaluations of attitudes and knowledge regarding EOL care prior to accessing the educational module, and a post-test evaluation following the module intervention. We recorded the type of hyperlinks (guideline or paper) accessed by learners, and stratified participants into groups based on link type accessed (none, either, or both). We used demographic and educational data to develop a multivariate mixed-effects regression analysis to develop adjusted predictions of attitudes and knowledge. RESULTS: 114 individuals participated. The majority had some professional exposure to EOL care (prior instruction 62%; EOL referral 53%; EOL discussion 56%), though most had no family (68%) or personal experience (51%). On bivariate analysis, non-partnered (p = .04), medical student training level (p = .03), prior palliative care referral (p = .02), having a family member (p = .02) and personal experience of EOL care (p < .01) were all associated with linking to auxiliary resources via hyperlinks. When adjusting for confounders, ß coefficient estimates and least squares estimation demonstrated that participants clicking on both hyperlink types were more likely to score higher on all knowledge and attitude items, and demonstrate increased score improvements. CONCLUSION: Auxiliary resources accessible by hyperlink are an effective adjunct to web-based learning in end-of-life care.

A Scalable Web-Based Module for Improving Surgical and Medical Practitioner Knowledge and Attitudes about Palliative and End-of-Life Care.

BACKGROUND: We built a web-based, interactive, self-directed learning module about end-of-life care. OBJECTIVE: The study objective was to develop an online module about end-of-life care targeted at surgeons, and to assess the effect of the module on attitudes towards and knowledge about end-of-life care. METHODS: Informed by a panel of experts in supportive care and educational assessment, we developed an instrument that required approximately 15 minutes to complete. The module targets surgeons, but is applicable to other practitioners as well. We recruited general surgeons, surgical subspecialists, and medical practitioners and subspecialists from UCLA and the GLA-VA (N=114). We compared pre- and post-intervention scores for attitude and knowledge, then used ANOVA to compare the pre- and postmodule means for each level of the covariate. We performed bivariable analyses to assess the association of subject characteristic and change in score over time. We ran separate analyses to assess baseline and change scores based on the covariates we had selected a priori. RESULTS: Subjects improved meaningfully in all five domains of attitude and in each of the six knowledge items. Individuals younger than 30 years of age had the greatest change in attitudes about addressing pain, addressing end-of-life goals, and being actively involved as death approached; they also had the most marked improvement in total knowledge score. Having a family member die of cancer within the last five years or a personal experience with palliative care or hospice were associated with higher change scores. CONCLUSIONS: A web-based education module improved surgical and medical provider attitudes and knowledge about end-of-life care.

Building a medical neighborhood in the safety net: an innovative technology improves hematuria workups.

OBJECTIVE: To analyze whether ereferral is associated with decreased time to completion of hematuria workup. METHODS: We included 100 individuals referred to Olive View-UCLA Medical Center for urologic consultation for hematuria. Half were referred before implementation of ereferral, and half were referred after the system was implemented. We performed bivariate analysis to assess correlations of baseline subject sociodemographic and clinical characteristics with ereferral status. We also created a multivariate linear regression model for log days to completion of hematuria workup, with ereferral as the main predictor and subject sociodemographic and clinical characteristics as covariates. RESULTS: Excluding cases with an infectious cause, the mean number of days from urinalysis documenting hematuria to completed hematuria workup was 404 days before ereferral and 192 days after implementation of ereferral (median 239 vs 170; 2-sample median P = .0013). Upper tract imaging was obtained at a median of 76 days after initial positive urinalysis in the absence of infection, 122 days before ereferral, and 41 days after implementation of ereferral (2-sample median P = .1114). In all cases, lower tract evaluation was completed after upper tract imaging. Our multivariable model evaluating factors associated with time to hematuria workup demonstrated that ereferral use was independently associated with shorter time to hematuria workup (P = .006). CONCLUSION: Electronic consultations can significantly shorten the time to work-up of hematuria in the safety net.

Embryo-fetal developmental toxicity study design for pharmaceuticals.

Assessment of potential developmental and reproductive toxicity of human pharmaceuticals is currently guided by the International Conference on Harmonization (ICH) S5(R2) document (available at http://www.ich.org). The studies that assess developmental hazard are generally conducted in rodents and rabbits. Based on the authors' collective experience, adequate designs (including range-finding studies) and the presentation of data for these studies are described in detail. In addition, the suggested initiation and then total duration of these studies in relation to clinical studies that enroll women of childbearing potential are described. Optional parameters that may be included in the studies are discussed, as are study designs that combine assessments of fertility and developmental toxicity. New methods that may replace or enhance current procedures are outlined. The details described herein will assist all laboratories performing these studies, individuals who need to plan for the studies, and regulatory agencies that ultimately review these studies.

The nonclinical fertility study design for pharmaceuticals.

Assessment of potential developmental and reproductive toxicity of human pharmaceuticals is currently guided by the ICH S5(R2) document, "Detection of Toxicity to Reproduction for Medicinal Products and Toxicity to Male Fertility." Studies that assess a candidate drug's effect on fertility are generally conducted in rats. The evolution of, and ultimate harmonization of, fertility study designs are reviewed, and specific elements of an acceptable design, as well as the recommendations for presentation of data, are described in detail. Additionally, the timing of nonclinical fertility studies in relation to clinical studies that enroll men and women of reproductive potential is reviewed. Possible strategies for combining fertility assessment with other study designs are also presented. This article provides testing laboratories, sponsors, and regulatory agencies with a comparison of current methods and designs, with the aim of providing a common understanding of the critical design features.

Selective use of voiding cystourethrography in children undergoing renal transplant evaluation.

PURPOSE: Voiding cystourethrography is a routine component in evaluating children awaiting renal transplantation. We examined whether this assessment is necessary in children with renal failure due to dysplasia/aplasia/hypoplasia syndrome and unknown etiology, which account for up to 25% of those with renal failure requiring renal replacement therapies. MATERIALS AND METHODS: We performed an institutional review board approved, retrospective review of 191 children undergoing transplantation between 2002 and 2007. We reviewed clinical factors associated with positive findings on voiding cystourethrogram. We also reviewed cystography results in children with chronic kidney disease due to renal dysplasia and unknown etiology. RESULTS: We identified 113 boys and 78 girls who underwent renal transplantation during the study period. Pre-transplant voiding cystourethrography was documented in 108 children (57%). Predictors of positive pre-transplant results included history of hydronephrosis, urinary tract infections and renal failure due to urological causes. No pre-transplant cystogram was positive in children with renal failure due to dysplasia or unknown etiology. CONCLUSIONS: We recommend selective use of voiding cystourethrography to evaluate children awaiting renal transplantation. We continue to support performing this test in children with renal failure due to urological causes and those with a history of urinary tract infection, hydronephrosis or voiding dysfunction. In the absence of these findings children with renal failure due to renal dysplasia/aplasia/hypoplasia syndrome or unknown etiology need not undergo pre-transplant voiding cystourethrography.

Developmental toxicity of artesunate in the rat: comparison to other artemisinins, comparison of embryotoxicity and kinetics by oral and intravenous routes, and relationship to maternal reticulocyte count.

BACKGROUND: The antimalarial, artesunate, is teratogenic and embryolethal in rats, with peak sensitivity on Days 10 and 11 postcoitum (pc). METHODS: We compared the developmental toxicity of structurally related artemisinins, dihdyroartemisinin (DHA), artemether (ARTM), and arteether (ARTE) to that of artesunate after oral administration to rats on Day 10 pc. In separate studies, embryolethality was characterized after single intravenous (IV) administration of artesunate on Day 11 pc, and toxicokinetic parameters following oral and IV administration were compared. Lastly, to determine whether maternal hematologic effects occurred at doses that affect embryonic erythroblasts, artesunate was orally administered on Day 11 pc at a dose that caused 100% embryolethality. RESULTS: All artemisinins caused the same pattern of embryolethality and fetal cardiovascular and skeletal abnormalities as previously shown for artesunate. In the IV study, marked postimplantation loss occurred at 1.5 and 3 mg/kg artesunate, but not at 0.75 mg/kg. Among the toxicokinetic parameters evaluated, only the DHA AUC(0-t) was similar at embryolethal oral and IV doses of artesunate. An embryolethal dose of artesunate caused a 15% decrease in maternal reticulocyte counts and no other hematologic effects. CONCLUSIONS: Several structurally related artemisinins cause similar developmental toxicity, suggesting an artemisinin class effect. Equally embryotoxic oral and IV treatments of one artemisinin compound (artesunate) produced similar systemic exposure to the artesunate metabolite, DHA, suggesting that DHA may be the proximate developmental toxicant. Embryolethal doses of artesunate only caused minor changes in maternal reticulocyte counts indicating that adult hematology parameters are not as sensitive as embryonic erythroblasts.

Laparoscopic heminephrectomy for upper-pole moiety in children using a 3-mm laparoscope and instruments.

PURPOSE: We report three cases of laparoscopic heminephrectomy in infants using a 3-mm laparoscope and instruments. To our knowledge, this is the first pediatric heminephrectomy series reported in the literature that utilized these small instruments. PATIENTS AND METHODS: Three pediatric patients underwent laparoscopic heminephrectomy for an upper-pole moiety in a duplicated collecting system with 3-mm laparoscopic ports and a 3-mm Storz 30 degrees laparoscope. RESULTS: All three cases were completed laparoscopically with total times of 120, 135, and 160 minutes. There were no intraoperative complications, and there was minimal blood loss. The optics of the laparoscope provided visibility and illumination similar to those available with larger-diameter laparoscopes. Two patients were discharged approximately 1 day postoperatively. The third patient required intravenous antibiotics to treat a urinary-tract infection and was discharged home 4 days postoperatively. All three patients had recovered fully by 2 weeks. CONCLUSION: The 3-mm laparoscope provides excellent visibility and illumination for performing heminephrectomy in the pediatric population. In addition, the 3-mm instruments provide excellent tissue handling, similar to that of the 5-mm tools.

Myelomeningocele information on the internet is accessible and of variable quality, and requires a high reading level.

PURPOSE: We assessed the accessibility, readability and quality of myelomeningocele information on the Internet. MATERIALS AND METHODS: We entered the term "spina bifida" into the Google, Yahoo! and Microsoft Network search engines, and stored the first 100 links from each Web site. A total of 164 unique Web sites remained for analysis, of which 159 were classified as relevant. Relevant Web sites were considered to have relevant content if more than 50% of the text was directly relevant to the disease, and to have relevant educational content if more than 50% of the text was aimed at relaying educational information. Readability was assessed using the Flesch-Kincaid Grade Level scale. The quality of the 159 Web sites with relevant content was assessed using American Public Health Association Criteria for Assessing Health Information on the Internet. Six criteria were assessed, namely credibility, content, links, design, interactivity and caveats. Web sites were analyzed by 2 separate medical doctors, with each reviewer blinded to the findings of the other. A weighted kappa statistic was used to calculate interrater reliability. RESULTS: Of 159 relevant sites 146 (91.8%) had relevant content and 122 (76.7%) had relevant educational content. The average Flesch-Kincaid reading level was 10.9 (range 6 to 12). Quality was assessed on a 3-point scale, with 1 denoting poor quality, 2 fair and 3 good. Average scores were 1.92 for credibility, 1.88 for content, 2.29 for links, 2.53 for design, 1.99 for interactivity and 2.90 for caveats. The weighted kappa statistic for interrater reliability was 0.83. CONCLUSIONS: Myelomeningocele information on the Internet is relatively accessible, requires a high reading level for comprehension and is of variable quality.

Outcomes of bladder neck closure for intractable urinary incontinence in patients with neurogenic bladders.

OBJECTIVE: Recent reports of outcomes of bladder neck closure for neurogenic urinary incontinence reveal poor initial continence and high vesicourethral fistula rates. We evaluated a large series of patients who underwent complete transection and closure of the bladder neck with modified abdominal stoma creation. MATERIALS AND METHODS: The medical records of 52 consecutive patients (23 males and 29 females) undergoing bladder neck closure by a single surgeon between July 1996 and January 2003 were reviewed. Mean follow up was 20 months (range 2-68 months) and mean age was 13.9 years (range 1.5-58 years). Forty-two patients (81%) underwent concomitant bladder augmentation. Catheterizable stomas included 46 appendicovesicostomies (88%) and six Monti tubes (12%). Of the 52 patients, 22 were confined to wheelchairs (42%), and the majority of patients had spinal cord pathology (40/52, 77%). Mean preoperative vesical leak point pressure was 25 cm/H(2)O (range 4-69 cm/H(2)O). RESULTS: Complete postoperative urinary continence was achieved in 44 patients (88%) after one procedure. Of the six patients who were incontinent (12%), one had a vesicourethral fistula (2%) and five had incontinence at the urinary diversion stoma (10%). Twelve of 50 patients had urinary stomal stenosis (24%), with six requiring urgent evaluation (12%) and six requiring surgical revision (12%). Postoperative urinary continence was unknown in two patients due to inadequate follow-up data. CONCLUSIONS: Our findings suggest that bladder neck closure is a safe and effective method of achieving urinary continence in children with neurogenic voiding dysfunction. While there are risks of stomal stenosis and fistula formation, modifications in surgical technique may reduce them to acceptable levels.

Measurement of bladder compliance can be standardized by a dimensionless number: theoretical perspective.

OBJECTIVES: To: (i) calculate traditional compliance (CTrad) for a normal bladder by DeltaV/DeltaPdet, where DeltaV is the mean volumetric capacity and DeltaPdet is the detrusor pressure rise; (ii) assess its usefulness; (iii) identify the variables that are necessary for correctly assessing bladder compliance; and (iv) using these variables, report a method that, because it includes the effect of patient age, sex and size, correctly assesses compliance for management strategies. METHODS: We obtained the mean volumetric capacity of a normal bladder (V(cap,NL)) and the mean detrusor pressure rise (P(cap,NL)) on filling a normal bladder to its volumetric capacity from our and other published work; (ii) calculated CTrad for a normal bladder; (ii) showed that the variables necessary for assessing compliance correctly are DeltaV, DeltaPdet, V(cap,NL), and P(cap,NL); and (iii) showed that the relationship among these is the dimensionless number, NWahl(-1), calculated as (DeltaV/V(cap,NL))/(DeltaPdet/P(cap,NL)). This value for individuals with a normal bladder was calculated, tabulated and graphed. RESULTS: Because a normal individual's bladder capacity increases with age while the detrusor pressure increase does not, CTrad increases with age and therefore cannot be used for assessing compliance. Published data substantiate our result that CTrad for an individual with a normal bladder varies from 6.3 at 0.5 years old to 90 mL/cmH2O at 18 years old. NWahl(-1) correctly assesses bladder compliance because it is the same for all normal cases; consequently NWahl(-1) is more practical for clinical use. CONCLUSIONS: Bladder compliance is standardized using DeltaV, DeltaPdet, V(cap,NL), and P(cap,NL) to give NWahl(-1), and bladder compliance is usefully reported using this value.