Impact of bilateral ureteral reimplantation at the time of complete primary repair of bladder exstrophy on reflux rates, renogram abnormalities and bladder capacity.

INTRODUCTION: Bilateral ureteral reimplantation at the time of the complete primary repair of bladder exstrophy (BUR-CPRE) has been proposed and has demonstrated favorable outcomes in the past. However, the potential benefits, including prevention of vesicoureteral reflux (VUR) and renal scarring must be tempered with any risks of reimplantation, persistent VUR, and the potential for overtreatment. We aimed to determine the impact of BUR-CPRE on reflux rates, renogram findings and bladder capacity. METHODS: An IRB approved registry of children treated for bladder exstrophy epispadias complex (BEEC) during a long-term international collaboration hosted in a region with high prevalence of BEEC was queried. Children undergoing primary CPRE for bladder exstrophy (BE) were identified. Surgical procedure and outcome measures nuclear medicine dimercaptosuccinic acid (DMSA) scintigraphy scans, voiding cystourethrogram (VCUG), and urodynamic study (UDS) were assessed for presence and degree of VUR, renogram abnormalities, and bladder capacity. RESULTS: A total cohort of 147 patients with BEEC was queried; 52 children (37 males, 71%) underwent primary CPRE for BE between 2009 and 2019 at median age of 1.1 years (IQR 0.6-1.9 years) with median follow up 4.4 years (IQR 2.4-6.4 years). BUR-CPRE was performed in 22/52 (42%). After BUR-CPRE, children were less likely to have VUR (any VUR present in 9 of 20 with imaging (45%) compared to 23 of 26 with imaging (82%) in the CPRE alone group (p = 0.007)). VUR in the BUR-CPRE group tended to be unilateral and lower grade in comparison to the CPRE alone group. DMSA abnormalities were less common in the BUR-CPRE group (4/19 (21%) vs.12/27 (44%)), although the difference did not reach statistical significance (p = 0.1). At 4 years follow-up, the BUR-CPRE group had a larger bladder capacity (p = 0.016). DISCUSSION: After BUR-CPRE, children had a lower rate of VUR, and when present, VUR was more often unilateral and lower grade compared to the CPRE alone group. Fewer numbers of children in the BUR-CPRE group depicted DMSA abnormalities. No children developed obstruction after BUR-CPRE and none have undergone repeat reimplantation. We documented a larger bladder capacity at the time of maximum follow-up available (4 years)-but further data are needed to confirm this observation. CONCLUSION: BUR-CPRE decreases the incidence and severity of VUR after CPRE, but the clinical significance of this remains unclear. We are encouraged by these initial results, but since BUR-CPRE does not uniformly eliminate VUR, we continue to proceed carefully in the well selected patient.

Yield of modern genetic evaluation for patients with proximal hypospadias and descended gonads.

INTRODUCTION AND BACKGROUND: Although the pediatric urologic community has embraced a multidisciplinary genetic and endocrine evaluation for newborns with ambiguous genitalia, this approach has been reserved for the most severe cases of undervirilized 46,XY individuals despite growing evidence that genetic differences are found even in patients whose only genitourinary anomaly appears to be proximal hypospadias. Identifying these genetic differences is vital for counseling patients as they move through puberty to parenthood as well as parents on future pregnancies. OBJECTIVE: The primary objective was to evaluate genetic diagnosis in patients with proximal hypospadias. The authors hypothesized the more sensitive genetic evaluation available in the modern era will reveal a high rate of patients with proximal hypospadias and descended testicles who are found to have a genetic difference, supporting a thorough genetic evaluation in these patients. STUDY DESIGN: A retrospective review was performed of all patients who underwent surgical correction for proximal hypospadias at a single institution from January 1, 2010, to December 31, 2016. Those with midshaft hypospadias were excluded as were patients whose primary surgery was performed at an outside institution. Patient characteristics, including demographics, clinical presentation, genetic evaluation, and referral to a multidisciplinary difference of sex development (DSD) clinic, were collected. The chi-squared test and t-test were used for analysis. RESULTS: There were 112 patients with proximal hypospadias who met the inclusion criteria. Of these, 91 had bilaterally descended testicles, whereas 21 had one or more undescended testicles. Thirty-three percent of patients with isolated proximal hypospadias received genetic testing of some kind, with 24% seen in the multidisciplinary DSD clinic. Four patients had an associated genetic syndrome identified, and 5 had a genetic difference of unknown clinical significance. Overall, 10% of patients with proximal hypospadias and descended testicles had an identifiable genetic difference vs 33% with associated cryptorchidism. Of these, one patient with proximal hypospadias and descended testicles had a genetic difference of known clinical significance that was likely to have been missed in the absence of an evaluation by a geneticist. DISCUSSION AND CONCLUSION: There was a high rate of identifiable genetic differences in patients whose only genitourinary abnormality was proximal hypospadias, especially with the 1% risk of a likely missed diagnosis. These findings support the discussion of a genetic evaluation for all patients with proximal hypospadias, regardless of the testicular location.

A Societies for Pediatric Urology survey of opioid prescribing practices after ambulatory pediatric urology procedures.

INTRODUCTION: Opioid dependence and abuse has been declared a national public health emergency, and overprescribing of opioids after surgery has been identified as a driving factor. To date, opioid prescribing after pediatric urology ambulatory surgery has not been well-described. OBJECTIVE: The study's objective was to assess pediatric urologists' practices in prescribing opioids for routine ambulatory procedures. STUDY DESIGN: A 23-question survey was created, including eight case vignettes describing routine procedures (orchiopexy, hydrocele repair, circumcision) across three age groups (8 months, 3 years, 13 years). Multiple choice questions asked about typical opioid type and duration for each case. Respondent attitudes and practice types were also evaluated. The survey was administered through the Societies for Pediatric Urology. RESULTS: Of the 102 respondents, 48% reported prescribing postoperative opioids for all cases described (Figure 1). Fourteen percent reported prescribing no opioids for all cases. Longer prescription duration was associated with older age (p = 0.003). Acetaminophen-hydrocodone was prescribed most commonly, while a few respondents reported prescribing acetaminophen-codeine. North Central and Southeastern respondents were more likely to prescribe opioids for all cases described (p = 0.003). The majority of respondents work in academic settings and had >10 years in practice. Only 16% believe that their patients take the majority of opioids prescribed, while only 35% provide education to their patients on proper disposal. DISCUSSION: There is significant variability in reported opioid prescribing practices after ambulatory procedures amongst pediatric urologists. Only 16% of respondents believe that patients take the majority of opioids prescribed, and only 14% reported never prescribing opioids for these procedures. There is an opportunity for guidelines and standardization of care for postoperative analgesia in this patient population. Given that overprescribing can lead to abuse and misuse, further work needs to be done to establish postoperative analgesia needs and to educate providers and families on proper prescribing and disposal. CONCLUSION: Pediatric urologists report prescribing opioids frequently after routine ambulatory procedures in infants, children, and adolescents despite believing that patients do not take the majority of the prescribed medication.

Using social media for patient-reported outcomes: A study of genital appearance and sexual function in adult bladder exstrophy patients.

INTRODUCTION: There have been few prior studies on patient-centered outcomes of adults with bladder exstrophy; those performed have been single institution reviews. In collaboration with the Association for the Bladder Exstrophy Communities (ABeC) - an international support network for patients and families living with bladder exstrophy - an anonymous social media survey was performed of patient-reported genital appearance and erectile function. OBJECTIVE: The study evaluated the Penile Perception Score (PPS) and the International Index of Erectile Function (IIEF-15) in adult men with bladder exstrophy. It was hypothesized that scores would be significantly lower than prior reported scores for men without the condition. STUDY DESIGN: After review by an anonymous patient advocate volunteer, the ABeC performed an anonymous online survey using social media. RESULTS: Adult men with bladder exstrophy reported PPS, and satisfaction with penile length and axis that were lower than prior published controls (n = 54, P < 0.05). Orgasmic function, sexual desire, and overall satisfaction were also lower (n = 46, P < 0.05). There was no difference in erectile function or intercourse satisfaction compared to controls. There was an association between PPS and erectile function, intercourse satisfaction, and overall satisfaction (P < 0.05) (Summary Fig.). Respondents identified urinary issues, genital appearance, and sexual function as the three main domains that warranted further research. CONCLUSION: This study found that PPS and IIEF-15 were low in adult men with bladder exstrophy, and worse perception of genital appearance was associated with worse sexual satisfaction. Social media is a novel tool for patient-centered outcomes research, and continued collaboration with patients and patient advocate groups is vital.

Early versus delayed closure of bladder exstrophy: A National Surgical Quality Improvement Program Pediatric analysis.

INTRODUCTION: Delayed closure of bladder exstrophy has become more popular; however, there is limited the evidence of its success. Existing literature focuses on intermediate and long-term outcomes, and short-term postoperative outcomes are limited by the small number of cases and varying follow-up methods. OBJECTIVE: The objectives of the current study were to: 1) compare 30-day complications after early and delayed closure of bladder exstrophy, and 2) evaluate practice patterns of bladder exstrophy closure. STUDY DESIGN: The National Surgical Quality Improvement Program Pediatric (NSQIPP) database from 2012 to 2015 was reviewed for all cases of bladder exstrophy closure. Early closure was defined as surgery at age 0-3 days, and delayed closure was defined as age 4-120 days at time of surgery. Demographic, clinical, and peri-operative characteristics were collected, as were postoperative complications, readmissions, and re-operations up to 30 days. Descriptive statistics were performed, and multivariate linear and logistic regression analyses were performed for salient complications. RESULTS: Of 128 patients undergoing bladder exstrophy closure, 62 were included for analysis, with 44 (71%) undergoing delayed closure. Mean anesthesia and operative times were greater in the delayed closure group, and were associated with more concurrent procedures, including inguinal hernia repairs and osteotomies. The delayed closure group had a higher proportion of 30-day complications, due to a high rate of blood transfusion (57% vs 11%). Wound dehiscence occurred in 6/44 (14%) delayed closures, as compared with 0/18 (0%) early closures. When compared with prior published reports of national data from 1999 to 2010, delayed closure was performed more frequently in this cohort (71% vs 27%). DISCUSSION: The NSQIPP provides standardized reporting of peri-operative characteristics and 30-day complications, allowing a comparison of early to delayed closure of bladder exstrophy across multiple institutions. Assessing short-term risks in conjunction with long-term follow-up is crucial for determining optimal management of this rare but complex condition. CONCLUSION: Delayed closure of bladder exstrophy is performed frequently, yet it carries a high rate of 30-day complications worthy of further investigation. This can be useful in counseling patients and families, and to understand practice patterns across the country.

A critical appraisal of continence in bladder exstrophy: Long-term outcomes of the complete primary repair.

INTRODUCTION: Long-term continence outcomes for patients with bladder exstrophy are lacking in the literature. The complete primary repair of exstrophy (CPRE) is a widely adopted approach that seeks to normalize anatomy at the initial repair, thereby allowing early bladder filling and cycling. Previous reports of continence following CPRE, however, are limited by variable follow-up duration and continence definitions. OBJECTIVE: To assess continence and factors associated with a positive outcome in a cohort of patients following CPRE with long-term follow-up. STUDY DESIGN: A retrospective chart review was conducted of all patients with primary bladder closure using CPRE at the present institution for classic bladder exstrophy from 1990 to 2010. Patients <6 years of age or with an incomplete continence assessment at last follow-up were excluded. Continence was defined as voiding volitionally with dry intervals of ≥3 h, which was consistent with other high-volume series in the literature. RESULTS: Twenty-nine of the 52 patients (56%) were eligible for inclusion. Twelve patients were continent at last follow-up, including seven boys and five girls. Mean follow-up for the entire cohort was 148 months. The Summary table displays comparisons between continent and incontinent patients. Of patients achieving continence, 42% did not require further continence operations, while 17% required only one additional continence operation. DISCUSSION: Long-term CPRE continence rates were lower than previously reported, but comparable to other series in the literature. Of those achieving continence, 59% will do so with zero or one additional operation. Sex and osteotomy status were not associated with continence outcomes, although age at follow-up was a predictor of continence, favoring older patients in the present series. The study was limited by lack of standardized, patient-reported continence outcomes and by the retrospective nature of the review. However, the data add to the literature of long-term continence outcomes and are important for counseling families both at initial repair and follow-up. CONCLUSIONS: Complete primary repair of exstrophy can achieve continence without additional operations in a subset of patients. Some patients, however, may not achieve continence until adolescence, underscoring the need for long-term urologic follow-up in patients with bladder exstrophy.

22 week assessment of bladder acellular matrix as a bladder augmentation material in a porcine model.

Previous studies on the reconstruction of porcine bladder using bladder acellular matrix allograft (BAMA) have indicated positive preliminary results with respect to graft shrinkage and cellular repopulation. The current study was conducted to investigate the feasibility of using BAMA in a similar model of bladder reconstruction out to longer time frames (22 weeks). At predetermined time points, the macroscopic, histological and mechanical properties of explanted native and BAMA tissues were evaluated and compared. Macroscopically, contracture of the BAMA was observed. The peripheral regions of the grafts experienced extensive cellular repopulation. Towards the centre however, all grafts were consistently devoid of organized smooth muscle bundles and a well-developed urothelium. An alteration in both the amount and organization of collagen was also observed within this region. Significant differences (p < 0.05) in the rupture strain and the elastic modulus of the BAMA compared to native bladder tissue appear to correlate with macroscopic graft contracture as well as the fibroproliferative tissue response of the matrix.

A population based analysis of continence outcomes and bladder exstrophy.

PURPOSE: Whereas the literature on bladder exstrophy is replete with outcomes of specific continence surgical procedures in highly select patients, there are no data on the outcomes related to continence for a complete exstrophy population, which is more comprehensive with respect to a variety of surgical procedures performed to achieve continence. To provide urologists and patients with an overview of potential continence outcomes devoid of any selection bias, we report on a comprehensive exstrophy population, focusing on the various procedures required for urinary continence. MATERIALS AND METHODS: We reviewed the charts of all patients with bladder and cloacal exstrophy who underwent a staged repair to achieve urinary continence at a single institution between 1988 and 1998. Urinary continence was then correlated to the types of surgical procedures, and subgroup analysis for predictors of urinary continence was performed. The type of bladder neck reconstruction allowed subgrouping cases into group 1-bladder neck reconstruction only, group 2-bladder neck reconstruction with augmentation and/or appendicovesicostomy and group 3-bladder neck closure. RESULTS: Of the 43 patients identified 26 were male, 4 had cloacal exstrophy and 3 had complex exstrophy variants with ectopic hindgut and spina bifida. Groups 1 to 3 comprised 9, 15 and 19 patients with urinary continence rates of 56%, 67% and 100%, respectively. The age at which patients became continent was delayed in groups 2 and 3 (8.2 and 8.7 years, respectively) compared to group 1 (4.8). Of all the potential variants measured gender was the strongest predictor of continence with 94% of females versus 69% of males achieving it. Of the males those with (57%) compared to those without (83%) a history of bladder neck stenosis or paraexstrophy flaps had worse continence. Repeat bladder neck reconstruction was only successful in 23% of patients. CONCLUSIONS: All patients can be rendered continent but many may achieve this successful outcome by other procedures following initial bladder neck reconstruction. When managing failed bladder neck reconstruction, the type of surgical repair chosen may need to address the need for enhanced bladder storage and the issue of potential bladder augmentation. The advances made in the treatment of the epispadiac urethra may now facilitate clean intermittent catheterization. Earlier recognition of the need for adjunctive storage procedures in addition to bladder neck reconstruction may facilitate the timing of providing enhanced continence, independence and self-esteem, and do so with fewer operative procedures. We speculate that the current complete urethral and bladder repair in newborns will add further to the storage functions of the native bladder tissues and improve the potential of achieving more effective bladder outlet control.

Pediatric genitourinary tumors.

Each year advances are made in the evaluation and management of genitourinary tumors in children. There is increased understanding of molecular and genetic processes in tumorigenesis. In addition, knowledge concerning the current treatment modalities is increasing, thus allowing us to tailor treatments in order to decrease long-term complications. In this article, we review this past year's literature regarding pediatric genitourinary tumors with emphasis on Wilms tumor, rhabdomyosarcoma, and testicular tumors.

Outcomes of primary valve ablation versus urinary tract diversion in patients with posterior urethral valves.

OBJECTIVES: Although valve ablation is the treatment of choice for patients with posterior urethral valves, debate continues as to the role of urinary diversion. We sought to retrospectively compare the clinical and radiologic outcomes between valve ablation and urinary diversion for patients with posterior urethral valves. METHODS: We retrospectively reviewed the records of 50 consecutive patients with posterior urethral valves since January 1995. On the basis of the initial renal function and radiologic findings, patients were divided into three groups: group 1, normal renal function and radiologically normal upper tracts; group 2, normal renal function with hydronephrosis and/or reflux; and group 3, azotemia with hydronephrosis or reflux. RESULTS: All 22 patients in group 1 were treated with valve ablation. After a mean follow-up of 32 months, these children had normal renal function and no evidence of upper tract deterioration. All 13 patients in group 2 were also treated with valve ablation. The radiologic abnormalities (hydronephrosis, reflux) resolved in 50% of cases, with an average follow-up of 28 months. Of the 15 patients in group 3, 7 underwent valve ablation and 8 underwent urinary diversion. Urinary diversion was performed in patients with renal deterioration and severe hydronephrosis and/or high-grade reflux. Renal function returned to normal in all patients who underwent valve ablation except one; renal function returned to normal in only 3 of 8 patients who underwent urinary diversion. Radiologically, the severity of the hydronephrosis and reflux was downgraded in patients who underwent valve ablation but not in the diverted group. CONCLUSIONS: Valve ablation is the mainstay of treatment for patients with posterior urethral valves. Prenatal and postnatal factors, such as renal dysplasia and urinary tract infection, respectively, rather than the posterior valve treatment dictate the long-term renal and radiologic outcomes.

Regeneration of functional bladder substitutes using large segment acellular matrix allografts in a porcine model.

PURPOSE: We previously reported on the short-term (4 weeks) morphometric analysis of a large bladder acellular matrix allograft used as a bladder bioprosthesis (average size 24 cm.2). We demonstrated cellular repopulation through the entire thickness of the graft. We now present the long-term (12 weeks) morphometric results of graft regenerated porcine bladders using segments measuring an average of 40 cm.2. MATERIALS AND METHODS: Bladders harvested from pigs were subjected to detergent and enzymatic extractions to render them acellular. Partial cystectomy was performed in 21 pigs and the defect was repaired with a bladder acellular matrix allograft (average size 40.52 cm.2). Of the animals 8 were sacrificed at 1, 2 and 4 weeks and 13 were sacrificed at 8 and 12 weeks. To evaluate cellular repopulation and matrix reorganization the native bladder and graft were analyzed using standard histological and immunofluorescent techniques. To evaluate for calcium deposits in the grafts a radiological evaluation of the graft was performed after explantation. RESULTS: All animals survived the surgical procedure and there were no significant urinary leaks. No stones were noted in any of the bladders. At 1 week there was a diffuse infiltration with acute inflammatory cells. At 2 weeks the luminal surface of the graft was lined with a single layer of urothelium, and there was stromal infiltration with unorganized smooth muscle cells and angiogenesis. At 4 weeks the urothelium was multilayered with organizing groups of smooth muscle cells and angiogenesis. At 8 and 12 weeks there was repopulation throughout the bladder acellular matrix allograft implant with all native cellular components participating. CONCLUSIONS: We present evidence that large patch bladder acellular matrix allograft implantation is technically feasible and may prove to be a viable surgical alternative to bladder augmentation with intestinal segments. Its advantages may include the potential for complete and functional regeneration of a bladder substitute.

The dysfunctional voiding scoring system: quantitative standardization of dysfunctional voiding symptoms in children.

PURPOSE: Academic research on pediatric nonneurogenic voiding dysfunction has long been hampered by the lack of a standardized reporting system for voiding symptoms. We evaluated the performance of a newly devised, objective instrument to quantify or grade the severity of abnormal voiding behaviors of children. MATERIALS AND METHODS: There were 10 voiding dysfunction parameters that were assigned scores of 0 to 3 according to prevalence, and possible total scores ranged from 0 to 30. The Dysfunctional Voiding Symptom Score was completed by 2 groups of patients. Group 1 consisted of patients 3 to 10 years old presenting to the pediatric urology clinic with a history of diurnal urinary incontinence, urinary tract infections or abnormal voiding habits. Group 2 consisted of an age matched cohort with no history of urological complaints presenting to hospital clinics outside of urology. Patients diagnosed with organic or anatomical disease, such as posterior urethral valves or meningomyelocele, were excluded from our analysis. RESULTS: Group 1 consisted of 104 patients (female-to-male ratio 4:1) with a median symptom score of 14 and group 2 consisted of 54 patients (female-to-male ratio 1.3:1) with a median score of 4. The dysfunctional voiding odds ratio was 2.93 for females compared to that of males. Using receiver operating characteristics the optimum cutoff score was 6.026 (sensitivity 92.77% and specificity 87.09%) for females and 9.02 (sensitivity of 80.95% and specificity of 91. 30%) for males. In addition, we found certain questions to be more reflective than others of dysfunctional voiding symptoms in our population. CONCLUSIONS: The Dysfunctional Voiding Symptom Score appears to provide accurate and objective, that is, numerical, grading of voiding behaviors of children. Comparative research studies of dysfunctional voiding diagnosis and response to therapy as well as objective measurements of treatment efficacy and outcomes analysis should be aided greatly by this system.

Lessons learned from laser tissue soldering and fibrin glue pyeloplasty in an in vivo porcine model.

PURPOSE: We compared sutured pyeloplasty to 2 newer techniques of tissue anastomosis, including laser soldered pyeloplasty using a diode laser with 50% albumin solder mixed with indocyanine green and fibrin glue. MATERIALS AND METHODS: We performed 53 pyeloplasties in 50 pigs using suture, laser or fibrin glue. In the immediate group anastomotic leak pressure was measured immediately postoperatively, and then animals were euthanized. At 1, 3 and 4 weeks postoperatively a pressure flow study at 10 cc per minute in cm. H2O was performed, and tissue was sent for histological and collagen content analysis. RESULTS: In the immediate studies laser soldering achieved a significantly higher mean anastomotic leak pressure (50.5 +/- 15.1 cm. H2O) than sutured (17.3 +/- 5.4) or fibrin glued (3.5 +/- 1.5) repairs. In the 1, 2 and 4-week studies animals in the sutured pyeloplasty group had no complications, and all pressure flow studies except 1 were normal. However, in the laser soldered groups we observed 8 urinomas in 19 animals, and most occurred during the first part of our study. This complication was prevented by stopping urine flow at the anastomotic site at laser irradiation and by improving application of the solder. Of the 11 animals in which pressure flow studies were performed only 2 were obstructed. Of the 7 chronic fibrin glue group 4 animals had urinomas and 2 had unobstructed pressure flow studies. Histological studies and immunohistochemical staining for collagen showed no differences in collagen distribution among the 3 procedures. CONCLUSIONS: Laser soldering and fibrin glue pyeloplasties are not superior in the long-term compared to sutured pyeloplasty. Fibrin glue in our animal model had the highest failure rate. Further improvements in the technical aspect of laser tissue welding need to be made to benefit from its theoretical advantages in minimally invasive surgery.

Are postoperative studies justified after extravescial ureteral reimplantation?

PURPOSE: We evaluated the usefulness of postoperative imaging studies after extravesical ureteroneocystostomy and identified patient subsets in which these studies are necessary. MATERIALS AND METHODS: Records of 438 patients who had undergone extravesical ureteroneocystostomy from 1991 to 1997 were reviewed retrospectively. Study inclusion criterion was primary reflux with at least 1 year of postoperative followup. Grades I to III reflux were defined as low, and grades IV and V were defined as high. All patients were on prophylactic antibiotics. Evaluation included ultrasound and a voiding cystourethrogram 3 months postoperatively, and if reflux persisted the studies were repeated at 12 months. RESULTS: A total of 438 patients (723 renal units) underwent extravesical ureteral reimplantation. At 3 months the procedure was successful in 93.2% of ureters (91.3% patients), and at 12 months the success rate increased to 97.9% of ureters (95.4% patients). There were 49 renal units in 38 cases that were refluxing at 3 months, 11 of which were contralateral. At 12 months reflux resolved spontaneously in 20 of 38 ipsilateral and 8 of 11 contralateral ureters. Of the remaining 18 ipsilateral units reflux was high grade preoperatively in 12 and persisted postoperatively in 4. There was a statistically significant difference in the success rate at 1 year between high (94%) versus low (99%) grade reflux (p = 0.007). Age and preoperative bladder function did not significantly affect the success rates but males had a lower success rate. Hydronephrosis was noted in 7.2% of ureters at 6 weeks and in only 0.005% at 12 months. CONCLUSIONS: Extravesical reimplantation is successful in treating vesicoureteral reflux. Postoperative voiding cystourethrogram should be reserved for high grade reflux. Limiting these studies will help reduce patient discomfort and the cost of treatment.

Pediatric genitourinary tumors.

Advances in our knowledge of pediatric genitourinary tumors are being made at both the basic science and clinical levels. The molecular mechanisms underlying these pediatric malignancies are being uncovered and will aid in uncovering novel treatments. Because of the high success rate in treating these tumors, treatment options are being modified to decrease both short- and long-term morbidity, while maintaining the improved survival.

Acellular bladder matrix allografts in the regeneration of functional bladders: evaluation of large-segment (> 24 cm) substitution in a porcine model.

OBJECTIVES: To evaluate the use of a large-segment (> 24 cm2) bladder substitution with porcine bladder acellular matrix allograft (BAMA) in a large animal model. Materials and methods Bladders were harvested from pigs at the time of necropsy and subjected to detergent and enzymatic extractions to render them acellular. The BAMA produced had the surgical handling and suture-retaining properties of normal bladder tissue. Six pigs had BAMA segments implanted under general anaesthesia, through a low midline abdominal incision and after partial cystectomy. The defect was repaired with a BAMA patch (mean size 43.88 cm2, range 12-72), with no urinary diversion. Two animals each were then killed at 9, 16 and 30 days and the bladders explanted. The native bladder and BAMA patch were analysed morphometrically to evaluate cellular re-population and matrix re-organization. RESULTS: All animals survived surgery; there were no urinary leaks and no stones detected in any of the bladders. At 9 days there was a diffuse infiltration with acute inflammatory cells, but no areas of necrosis. There were isolated areas of smooth muscle cell (SMC) infiltration of the BAMA. At 16 days the luminal surface was lined with a single layer of urothelium, there was stromal infiltration with disorganized SMC and angiogenesis, with mature vessels in the BAMA patch. At 30 days the urothelium was multilayered with organizing groups of SMCs and angiogenesis. The highest cell density was at the periphery of the repopulated BAMA patch, decreasing towards the centre. CONCLUSIONS: The implantation of large patches of BAMA is technically feasible and may prove to be a viable surgical alternative to bladder augmentation with intestinal segments. The advantages of BAMA include the potential for complete and functional regeneration of a bladder substitute. This model provides a tool with which to obtain a better understanding of the cellular and molecular aspects of matrix re-population.

The use of magnetic resonance imaging in the diagnosis and followup of pediatric pelvic rhabdomyosarcoma.

PURPOSE: Previous radiological descriptions of pelvic rhabdomyosarcoma emphasized ultrasonography and computerized tomography (CT). Few reports are available on the use of magnetic resonance imaging (MRI) for diagnosing and following pelvic rhabdomyosarcoma. We retrospectively compared MRI to CT for diagnosing and following children with pelvic rhabdomyosarcoma. MATERIALS AND METHODS: We treated 4 boys and 3 girls for pelvic rhabdomyosarcoma. Initial and followup evaluations included pelvic CT and MRI at intervals determined by treatment and disease status. We retrospectively reviewed the clinical charts and imaging studies of these patients. The initial radiological report was evaluated and then 1 radiologist reviewed all studies. Attention was directed toward identifying lesions revealed by CT or MRI but not by the other modality. RESULTS: MRI detected all lesions shown by CT. On the other hand, MRI detected residual disease in 1 case that was not demonstrated by CT. In 2 other patients MRI was superior to CT for delineating the local extent of disease, especially urethral involvement. CONCLUSIONS: Compared with CT, MRI improves the detection of residual pelvic rhabdomyosarcoma. Tissue planes are well delineated, allowing more accurate assessment of tumor invasion into adjacent structures. MRI is the imaging modality of choice for following pediatric patients with pelvic rhabdomyosarcoma.

Initial experience with endoscopic holmium laser lithotripsy for pediatric urolithiasis.

PURPOSE: Due to the unavailability of suitable pediatric instruments children have not benefited from advances in endoscopic lithotripsy. This limitation may be overcome by the holmium: YAG laser. We evaluated the indications for, and efficacy and complications of holmium:YAG laser lithotripsy. MATERIALS AND METHODS: We retrospectively reviewed all cases of laser lithotripsy. Access to the calculus was antegrade or retrograde. A solid state holmium:YAG laser was used. RESULTS: Eight patients 4 to 14 years old underwent laser lithotripsy during the study period. Average calculous surface area was 357.13 mm.2 (range 14 to 1,645). Five patients required 1 procedure to render them stone-free, while the remaining 3 required multiple procedures. No complications were associated with laser lithotripsy. CONCLUSIONS: The ability of the holmium:YAG laser to pulverize urinary calculi makes it an alternative choice for lithotripsy. In our series all patients are stone-free with stable renal function. The advantages of the holmium:YAG laser are that it may be precisely applied via small fibers, and it pulverizes calculi with minimal scattering of energy and retropulsion of the calculus, decreasing trauma to tissues at the perioperative site. There is also a lower risk of residual fragments, which is associated with a lower incidence of calculous regrowth. Holmium: YAG laser is safe and effective for treating pediatric urolithiasis.