Learning from the learning curve: factors associated with successful endoscopic correction of vesicoureteral reflux using dextranomer/hyaluronic acid copolymer.

Purpose: Conflicting reports exist regarding the parameters guiding successful correction of vesicoureteral reflux using dextranomer/hyaluronic acid copolymer. We performed logistic regression analysis to evaluate the effect of injected volume while adjusting for other factors potentially associated with success following dextranomer/hyaluronic acid copolymer injection.

Materials And Methods: Between July 2003 and June 2006, 126 consecutive patients (34 boys and 92 girls) with a mean +/- SD age of 6.

Risk factors for recurrent ureteropelvic junction obstruction after open pyeloplasty in a large pediatric cohort.

Purpose: Recurrent ureteropelvic junction obstruction after open pyeloplasty is a serious complication for which treatment remains challenging. We identified risk factors for persistent obstruction.

Materials And Methods: We retrospectively reviewed the charts of 401 children who underwent open dismembered pyeloplasty between 1997 and 2005.

Outcome analysis and cost comparison between externalized pyeloureteral and standard stents in 470 consecutive open pyeloplasties.

Purpose: Despite the widespread use of ureteral stents for pyeloplasty by pediatric urologists there is ongoing controversy regarding the most advantageous type of transanastomotic drainage. We compared patients who underwent placement of an externalized pyeloureteral Salle intraoperative pyeloplasty stent (Cook Urological, Spencer, Indiana) to those who had a standard Double-J ureteral stent placed to assess the benefits, drawbacks and costs of each modality during open pyeloplasty.

Materials And Methods: Our study sample comprised 470 age matched children who underwent primary open pyeloplasty in an 11-year period.

Does mechanical stimulation have any role in urinary bladder tissue engineering?

Introduction: Tissue engineering of the urinary bladder currently relies on biocompatible scaffolds that deliver biological and physical functionality with negligible risks of immunogenic or tumorigenic potential. Recent research suggests that autologous cells that are propagated in culture and seeded on scaffolds prior to implantation improve clinical outcomes. For example, normal urinary bladder development in utero requires regular filling and emptying, and current research suggests that bladders constructed in vitro may also benefit from regular mechanical stimulation.

Effect of donor pneumoperitoneum on early allograft perfusion following renal transplantation in pediatric patients: an intraoperative Doppler ultrasound study.

Decreased perfusion and trauma during laparoscopic harvesting are proposed causative factors for DGF and rejection in children following renal transplantation with laparoscopic donor nephrectomy (LDN) allograft. We performed a retrospective review of 11 children who underwent LDN transplant and 11 preceding patients who underwent ODN transplant. Intraoperative DUS findings, creatinine values and clearance, time to nadir creatinine and AR episodes were compared.

Interactions of constipation, dysfunctional elimination syndrome, and vesicoureteral reflux.

Vesicoureteral reflux (VUR) is simply described as incompetence of the unidirectional valve at the ureterovesical junction (UVJ), leading to backflow of urine to the kidney. Today, it is clear that VUR is not only related to the UVJ function but also to a combination of processes including immunity, bladder and pelvic floor function, dysfunctional voiding, and constipation. Although our surgical aims directed towards improving the valve coaptation at the UVJ, we understand today the importance of the diagnosis and treatment of constipation and dysfunctional voiding adjunctively.

Single-institutional study on role of ureteroscopy and retrograde intrarenal surgery in treatment of pediatric renal calculi.

Objectives: Ureteroscopy (URS) is accepted as a primary modality to treat ureteral calculi in children and extracorporeal shock wave lithotripsy and percutaneous nephrolithotomy continue to be the primary option for renal stones. We report our experience with the use of URS in managing pediatric upper tract calculi and evaluate the results in relation to stone location, size, and the use of URS as a primary or secondary treatment modality.

Methods: A retrospective chart review was performed for all children who underwent URS for renal stones from 1999 to 2004.

Potential complications with the prescrotal approach for the palpable undescended testis? A comparison of single prescrotal incision to the traditional inguinal approach.

Purpose: Prescrotal orchiopexy is emerging as an alternative surgical approach to undescended testicles. We compare operative times, success rates and complications of single incision prescrotal orchiopexy and the traditional inguinal approach.

Materials And Methods: During a 3-year period all patients who underwent prescrotal orchiopexy were retrospectively reviewed and compared to age matched controls operated on via the traditional inguinal approach.

The impact of constipation on the urinary tract system.

The rate of constipation and bowel disorders is underestimated in children and adolescence who suffer from functional urinary tract disorders like enuresis and incontinence. The alimentary and the urinary systems act with a close anatomical and functional relation, malfunctioning of either system will affect the other. Children and adolescents with urinary dysfunctional symptoms have a higher rate of bowel disorders, including constipation and soiling, and vice versa.

Porcine bladder acellular matrix (ACM): protein expression, mechanical properties.

Experimentally, porcine bladder acellular matrix (ACM) that mimics extracellular matrix has excellent potential as a bladder substitute. Herein we investigated the spatial localization and expression of different key cellular and extracellular proteins in the ACM; furthermore, we evaluated the inherent mechanical properties of the resultant ACM prior to implantation. Using a proprietary decellularization method, the DNA contents in both ACM and normal bladder were measured; in addition we used immunohistochemistry and western blots to quantify and localize the different cellular and extracellular components, and finally the mechanical testing was performed using a uniaxial mechanical testing machine.

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.

Insertion of an internal-external nephroureteral stent during pediatric laparoscopic pyeloplasty: description of the technique.

Objectives: We present a technique for inserting an internal-external nephroureteral antegrade stent during a laparoscopic pyeloplasty.

Methods: We describe the step-by-step technique for external-internal stent insertion during transperitoneal laparoscopic pyeloplasty: (1) Before completion of the ueretopelvic junction anastomosis, a 14-gauge angiocatheter is inserted and the external-internal stent is advanced under direct vision downward into the ureter. (2) A percutaneous access to the intrarenal collecting system is then performed by using another 14-gauge angiocatheter.

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.

Failed pyeloplasty in children: comparative analysis of retrograde endopyelotomy versus redo pyeloplasty.

Purpose: We compared retrograde endopyelotomy to redo pyeloplasty for the treatment of failed pyeloplasty in children.

Materials And Methods: Of 32 patients with recurrent ureteropelvic junction obstruction retrograde endopyelotomy was performed in 18 and redo pyeloplasty was performed in 14. Patient age, gender, side, stent placement at initial pyeloplasty, presentation of secondary ureteropelvic junction obstruction, hospital stay, complications and success rates were compared.

Minimally invasive approach for treatment of urinary and fecal incontinence in selected patients with spina bifida.

Objectives: At our institution, the use of cecostomy tubes has provided a successful method for managing severe constipation in patients with spina bifida, with good patient and caretaker satisfaction and minimal morbidity. We have developed a modified technique to allow placement of the cecostomy tube under direct vision during laparoscopic appendicovesicostomy. We present our initial experience and technique.

Comparative analysis of tubularized incised plate versus onlay island flap urethroplasty for penoscrotal hypospadias.

Purpose: Despite being the dominant technique for repair of distal hypospadias, application of the tubularized incised plate approach for penoscrotal hypospadias remains controversial. We report our experience with severe hypospadias, comparing tubularized incised plate to transverse island flap onlay urethroplasty.

Materials And Methods: We retrospectively reviewed consecutive patients with penoscrotal hypospadias presenting between 1998 and 2006.

Pediatric laparoscopic pyeloplasty in a referral center: lessons learned.

Purpose: We present our first-year experience with pediatric transperitoneal laparoscopic dismembered pyeloplasty (TLDP) in a large referral center.

Patients And Methods: A chart review was conducted in 27 consecutive children (M:F 23:4) aged 4 to 17 years (mean 9.7 years) with ureteropelvic junction obstruction who underwent TLDP (21 on the left, 6 on the right) in 2005.

Regional variability, processing methods, and biophysical properties of human fascia lata extracellular matrix.

This study aims to assess the regional variability, processing methods, mechanical, biochemical, and cellular properties of human fascia lata as a scaffold for soft tissue repair and tissue engineering applications. Ten pairs of fascia lata (donor age 18-55) were used. One fascia patch from each pair was used to assess the geometric and biomechanical variability of fresh fascia.

Pediatric laparoscopic ileal cystoplasty: complete intracorporeal surgical technique.

Introduction: Despite the widespread introduction of laparoscopy in pediatric urology, many reconstructive procedures, such as augmentation cystoplasty, are still performed in an open fashion because of the perceived intricacy and demanding nature. Because we continue to introduce advanced laparoscopic skills into the care of children, we describe our technique for complete intracorporeal laparoscopic enterocystoplasty in a pediatric patient.

Technical Considerations: The key elements of the procedure include a thorough preoperative mechanical bowel preparation; cystoscopic evaluation and placement of externalized ureteral stents; transperitoneal placement of three radially dilating trocars (one large enough to allow advancement of a laparoscopic stapler); the selection and measurement of a 20-cm ileum segment with sufficient mobility; the development of the perivesical space and lateral attachments, followed by a generous cystotomy; isolation of the bowel segment and side-to-side anastomosis using endoscopic staplers; intracorporeal irrigation of the segment followed by antimesenteric detubularization; temporary stabilization of the bowel segments using percutaneous traction sutures, allowing the avoidance of extra trocars in children with limited intraabdominal space; intracorporeal suturing of the detubularized bowel into a U-shaped configuration; fixation of the ileal patch to the bladder, followed by watertight anastomosis with running sutures; irrigation and placement of a closed suction drain in the pelvis; and cystography 4 to 6 weeks postoperatively.

Quantifying angiogenesis in VEGF-enhanced tissue-engineered bladder constructs by dynamic contrast-enhanced MRI using contrast agents of different molecular weights.

Purpose: To compare Gadomer, a macromolecular magnetic resonance (MR) contrast agent, and gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) for quantifying angiogenesis in tissue-engineered bladder constructs.

Materials And Methods: Constructs enhanced with vascular endothelial growth factor (VEGF) were grafted onto the bladder of 12 rabbits (N= 3/VEGF, VEGF = 0,10,15,20 ng/g tissue). After eight days dynamic contrast-enhanced MRI (DCE-MRI) was performed in each animal using Gadomer and Gd-DTPA, separated by a one-hour interval.

Does peak systolic velocity correlate with renal artery stenosis in a pediatric renal transplant population?

PSV of renal transplant vessels, calculated during allograft ultrasonography, has previously been shown to correlate with TRAS. Controversy exists regarding the threshold PSV value (adult range: 1.5-3.

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.

Impact of fibrin glue and urinary bladder cell spraying on the in-vivo acellular matrix cellularization: a porcine pilot study.

Purpose: Urinary bladder tissue engineering utilizing autologous cell-seeded scaffolds requires enough bladder cells to populate a large surface area which may be difficult to obtain from abnormal bladders. We evaluated whether a fibrin glue spray technique enhances cell seeded acellular matrix (ACM) repopulation in a porcine bladder model.

Materials And Methods: Porcine urothelial and smooth muscle cells cultured from open bladder biopsy were sprayed with or without fibrin glue onto porcine bladder ACM.

Update on Wilms' tumor in children.

Although rare, Wilms' tumor is the most common primary renal malignancy in children and is associated with a number of congenital anomalies and documented syndromes. Appropriate laboratory, radiologic and pathologic investigations are necessary components of the evaluation of children with suspected Wilms' tumor. This provides accurate diagnosis and subsequent staging; information which is essential to generate a multidisciplinary treatment plan utilizing surgery, chemotherapy and radiotherapy.