M. Chad Wallis

Outcome Analysis of Retroperitoneal Laparoscopic Heminephrectomy in Children

Purpose: Retroperitoneal laparoscopic heminephrectomy is a relatively new, well tolerated, minimally invasive alternative to open surgery for children with a nonfunctioning moiety in a duplex kidney. We collected data to assess outcomes in our experience with this procedure.Materials and Methods: Data were retrospectively gathered on all patients operated on for retroperitoneal laparoscopic heminephrectomy at our institution between February 2001 and November 2004. Followup ultrasound was performed in all patients, and additional imaging was done only when clinically indicated.Results: Retroperitoneal laparoscopic heminephrectomy was performed in 18 girls and 4 boys (18 upper and 5 lower pole moieties). Indications included ureterocele (12 patients), ectopic ureter (9) and vesicoureteral reflux (5). Mean age at surgery was 5 years (range 4 months to 18 years). Four patients required conversion to an open procedure due to inadequate exposure and were excluded from further review. Urine leaks developed post...

Feasibility Study of a Novel Urinary Bladder Bioreactor

We have devised a bioreactor to simulate normal urinary bladder dynamics. The design permits a cell-seeded scaffold made from a modified porcine acellular matrix to be placed between 2 closed chambers filled with culture medium and be mechanically stimulated in a physiologically relevant manner. Specifically designed software increased hydrostatic pressure from 0 to 10 cm of water in a linear fashion in 1 chamber, resulting in mechanical stretch and strain on the scaffold. Pressure was increased over 55 min (filling) and then decreased to 0 over 10 s (voiding). Commercially available small intestinal submucosa scaffolds were used to test the mechanical capabilities of the bioreactor, and pressure waveforms were generated for up to 18 h. Scaffolds were seeded with bladder smooth muscle or urothelial cells and incubated in the bioreactor, which generated pressure waveforms for 6 h. Scaffold integrity was preserved as seen through Massons trichrome staining. No obvious contamination of the system was noted. Hematoxylin and eosin staining showed presence of cells after incubation in the bioreactor, and immunohistochemistry and real-time reverse transcriptase polymerase chain reaction suggested continued cellular activity. Cellular orientation tended to be perpendicular to the applied pressure. Preliminary results suggest that our bioreactor is a suitable model for simulating normal physiological conditions of bladder cycling in an ex vivo system.

What are the Most Powerful Determinants of Endoscopic Vesicoureteral Reflux Correction? Multivariate Analysis of a Single Institution Experience During 6 Years

PURPOSE As the indications for endoscopic correction of vesicoureteral reflux continue to expand, the emergence of potential predictive variables has been noted. We used univariate and multivariate statistical analyses to find the most significant predictors of correction to improve patient selection. MATERIALS AND METHODS A consecutive series of patients treated at a single institution was reviewed. Between August 1998 and August 2004, 232 children endoscopically injected with polydimethylsiloxane were identified, representing 351 refluxing units. A total of 23 variables were subjected to statistical analysis to detect predictors of reflux correction after injection. All identified patients with complete data and followup evaluations were included irrespective of anatomical variations, previous interventions or comorbidities. RESULTS The overall success rate by patient and renal unit was 65% and 72%, respectively. In patients with a single system low grade (1-3) vesicoureteral reflux who did not previously undergo injection this success rate increased to 80%. Univariate analysis demonstrated that higher physician experience, low preoperative vesicoureteral reflux grade, absent renal scars and no previous injections were statistically significant predictors of vesicoureteral reflux correction (p <0.05). A history of febrile urinary tract infections and a duplex system did not attain significance (p = 0.069 and 0.076, respectively). On multivariate statistical evaluation only physician experience, preoperative vesicoureteral reflux grade and the number of previous injections remained significant. CONCLUSIONS Multivariate analysis of our data showed the most important determinants of vesicoureteral reflux correction after endoscopic injection. Prospective validation will allow us to generate nomograms to better select and counsel patients who would benefit from vesicoureteral reflux treatment.

Pediatric Urinary Stone Composition in the United States

PURPOSE The incidence of urolithiasis in children is increasing. However, stone composition studies in this population are limited. We sought to determine the effects of age, gender and geographical location on urinary stone composition in the United States pediatric population. MATERIALS AND METHODS We obtained composition analyses for all urinary stones submitted to a reference laboratory between 2000 and 2009. Stones were excluded if the patient was younger than 1 year or older than 18 years. Stone composition was determined by Fourier transform infrared spectroscopy. Logistic regression analysis was performed to determine associations between stone composition frequency and age, gender and geographical region. RESULTS A total of 5,245 stones were included in our analysis. Calcium was found in 89.2% of stones. The percentage of stones containing calcium oxalate increased, while magnesium ammonium phosphate and ammonium acid urate containing stones decreased with age. Calcium oxalate and magnesium ammonium phosphate containing stones were more common in females, while uric acid stones were more common in males. Additionally, significant differences in stone composition frequency were noted between males and females in specific age groups and between age groups within the same gender. Geographical distribution was not significantly associated with stone composition. CONCLUSIONS This series is the largest analysis to date of urinary stone composition in the pediatric population in the United States. Age and gender were significantly associated with stone composition, while geographical region was not significantly associated with stone composition.

250 consecutive unilateral extravesical ureteral reimplantations in an outpatient setting.

PURPOSE Unilateral extravesical ureteral reimplantation is comparable to intravesical procedures and more effective than subureteral injection to resolve vesicoureteral reflux. Initial reports showed that the procedure could be feasibly done on an outpatient basis. We present further data on a large series of consecutive, planned, outpatient unilateral extravesical ureteral reimplantations. MATERIALS AND METHODS A total of 250 consecutive patients underwent scheduled outpatient unilateral extravesical ureteral reimplantation. We retrospectively reviewed their records. Patient data were collected on reflux laterality and grade, operative time, hospital stay, complications, need for rehospitalization and resolution rate on radiography 1 month postoperatively. RESULTS A total of 209 females (84%) and 41 males (16%) underwent planned outpatient extravesical ureteral reimplantation, including on the left side in 158 (63%) and on the right side in 92 (37%). Mean reflux grade was 3.2 with grades II to V in 64 (26%), 96 (38%), 74 (30%) and 16 cases (7%), respectively. Average operative time was 63 minutes and average length of stay, defined as time from initial admission in to discharge home, was 6.2 hours (range 3 to 10 hours). Short-term and late complications occurred in 9 (3.6%) and 8 patients (3.2%), respectively. CONCLUSIONS Extravesical ureteral reimplantation for unilateral vesicoureteral reflux may be consistently done on an outpatient basis with a reasonable complication rate and a low postoperative hospital admission rate.

Design and Methodological Considerations of the Centers for Disease Control and Prevention Urologic and Renal Protocol for the Newborn and Young Child with Spina Bifida

PURPOSE Care of children with spina bifida has significantly advanced in the last half century, resulting in gains in longevity and quality of life for affected children and caregivers. Bladder dysfunction is the norm in patients with spina bifida and may result in infection, renal scarring and chronic kidney disease. However, the optimal urological management for spina bifida related bladder dysfunction is unknown. MATERIALS AND METHODS In 2012 the Centers for Disease Control and Prevention convened a working group composed of pediatric urologists, nephrologists, epidemiologists, methodologists, community advocates and Centers for Disease Control and Prevention personnel to develop a protocol to optimize urological care of children with spina bifida from the newborn period through age 5 years. RESULTS An iterative quality improvement protocol was selected. In this model participating institutions agree to prospectively treat all newborns with spina bifida using a single consensus based protocol. During the 5-year study period outcomes will be routinely assessed and the protocol adjusted as needed to optimize patient and process outcomes. Primary study outcomes include urinary tract infections, renal scarring, renal function and bladder characteristics. The protocol specifies the timing and use of testing (eg ultrasonography, urodynamics) and interventions (eg intermittent catheterization, prophylactic antibiotics, antimuscarinic medications). Starting in 2014 the Centers for Disease Control and Prevention began funding 9 study sites to implement and evaluate the protocol. CONCLUSIONS The Centers for Disease Control and Prevention Urologic and Renal Protocol for the Newborn and Young Child with Spina Bifida began accruing patients in 2015. Assessment in the first 5 years will focus on urinary tract infections, renal function, renal scarring and clinical process improvements.

Risk Assessment of Incidentally Detected Complex Renal Cysts in Children: Potential Role for a Modification of the Bosniak Classification

PURPOSE Incidentally detected complex renal cysts in children are a rare but worrisome occurrence due to the perceived potential risk of malignancy. We examined the natural history of such cysts in a cohort of children. MATERIALS AND METHODS We obtained access to a database containing all radiology reports generated at a single institution from 1996 to 2004. We used key words to limit our search, subsequently reviewing charts and images to confirm the diagnosis of a complex renal cyst and to collect clinical data. Cases were categorized according to a modification of the Bosniak classification, using ultrasound in most patients and computerized tomography or magnetic resonance imaging when available. RESULTS Complex renal cysts were identified in 39 children. Mean patient age at presentation was 7 years. Mean cyst size was 1.6 cm. A total of 18 cases diagnosed by ultrasound only were observed with serial imaging. Additional contrast enhanced computerized tomography or magnetic resonance imaging was performed in 21 of 39 patients (54%). Surgical resection was performed in 5 patients and pathological evaluation revealed benign cyst in 3 (modified Bosniak class II in 2 patients and class III in 1) and renal cell carcinoma in 2 (III in 1 and IV in 1). All other patients had modified Bosniak class II cysts, which remained essentially unchanged during a mean followup of 26.8 months (range 9 to 70). CONCLUSIONS While not validated in children, our data suggest the modified Bosniak classification appears useful as a guideline to direct the management of complex renal cysts in the pediatric population.

Retrograde Percutaneous Access for Kidney Internal Splint Stent Catheter Placement in Pediatric Laparoscopic Pyeloplasty: Avoiding Stent Removal in the Operating Room

BACKGROUND AND PURPOSE Laparoscopic pyeloplasty has become increasingly used in the pediatric population for ureteropelvic junction (UPJ) obstruction. When choosing laparoscopic pyeloplasty, it is common to leave a Double-J ureteral stent across the anastomosis. In adult practice, this stent is easily removed in the office during follow-up; however, in pediatrics, cystoscopy and stent removal necessitates a trip back to the operating room. We report a novel method for placing a Kidney Internal Splint Stent (KISS) catheter, which can then be removed in the office during follow-up. METHODS The UPJ is dismembered, spatulated, and the new lateral edges are anastomosed as usual. With the renal pelvis still open, a STING needle is passed through the epigastric midline port. The laparoscope is used to visualize an appropriate posterior calix and direct the needle through the calix and out the back of the patient. A 7F vascular dilator is then threaded over the needle in retrograde fashion and into the collecting system. A 4F or 6F KISS catheter is then threaded through the dilator and down the ureter. The dilator is removed and the surgery is then finished according to the surgeons preference. RESULTS We have placed this catheter in nine children without difficulties or intraoperative complications. Mean age was 8 years. All stents were otherwise removed at an average of 13 days in the office without difficulty. Three patients had problems with intermittently poor drainage necessitating flushing; in one of these patients, a recurrence of the UPJ obstruction developed. CONCLUSION A laparoscopic approach for KISS catheter placement is a technically feasible and advantageous technique when placing a stent for a pyeloplasty repair. This eliminates a trip back to the operating room for stent removal in the pediatric population and likely decreases bladder irritation.

Parameatal urethral cysts in prepubertal males.

PURPOSE Parameatal urethral cyst in boys is an uncommon and often poorly understood condition. We describe the largest known series of 18 prepubertal boys with parameatal cysts. MATERIALS AND METHODS We retrospectively reviewed the charts of all pediatric patients at our institution diagnosed with a penile cyst according to our office database between 1992 and 2010. Charts were reviewed to determine patient demographics, symptomatology, pathology, cyst characteristics and treatment. RESULTS We identified 18 patients during the last 18 years who were diagnosed with a parameatal cyst. Most patients (66%) were asymptomatic. All cysts were less than 1 cm in diameter. Of the patients 50% were circumcised before presentation and 78% underwent surgical excision. There have been no recurrences in patients who underwent excision. One patient had spontaneous resolution of the cyst during the first few weeks of life. Pathology results were available for 6 patients. Three specimens contained a single type of epithelium and 3 contained a combination of transitional, cuboidal and/or columnar epithelia. The transitional and cuboidal epithelia were the most common components. There was no evidence of malignancy in any of the specimens and only 1 specimen contained an inflammatory infiltrate. CONCLUSIONS Parameatal cysts are a benign, usually asymptomatic condition that may contain a variety of epithelial types. The cysts may resolve spontaneously in neonates but are also easily excised with minimal risk of recurrence.

Reliability of voiding cystourethrogram for the grading of vesicoureteral reflux

OBJECTIVE The voiding cystourethrogram (VCUG) is a commonly employed radiographic test used in the management of vesicoureteral reflux (VUR). Recently, the reliability of VCUG to accurately grade VUR has been questioned. The purpose of this study is to examine reliability of the VCUG for the grading of VUR in a setting mimicking daily practice in a busy pediatric hospital. MATERIALS AND METHODS Two-hundred consecutive VCUGs were independently graded by two pediatric urologists and two pediatric radiologists according to the International Classification of Vesicoureteral Reflux. A weighted kappa coefficient was calculated to determine inter-rater agreement and a modified McNemar test was performed to assess rater bias. Further assessment for impact on clinical and research decision-making was made for disagreement between grades II and III. RESULTS Weighted kappa values reflect strong reliability of VCUG for grading VUR between and among urologists and radiologists ranging from 0.95 to 0.97. There was statistically significant bias with radiologists reporting higher grades. Despite high kappa values, disagreement between raters was not infrequent and most common for grades II-IV. CONCLUSIONS VCUG is reliable for grading VUR, but small differences in grading between raters were detected and may play an important role in clinical decision-making and research outcomes.