Development and validation of a novel fetal vesico-amniotic shunt, the vortex shunt.

Fetal lower urinary tract obstruction (LUTO) is a severe malformation associated with an up to 80% mortality risk as well as significant renal and pulmonary morbidity in survivors. Fetal vesico-amniotic shunts (VAS) bypass the bladder obstruction, improve amniotic fluid volume and enhance in-utero pulmonary development. VAS has been shown to reduce respiratory morbidity and mortality in the neonatal period without proven benefit on long-term renal and bladder function. Clinically available shunts are associated with an up to 80% dislodgement rate, leading to repeat invasive procedures which increase fetal and maternal risks. We developed a novel "Vortex" shunt, which incorporates enhanced fixation to reduce dislodgement, a one-way valve to optimize in-utero bladder function, and enhanced sonographic echogenicity that optimizes the accurate deployment. Following the validation of these characteristics in initial benchtop experiments we have moved to feasibility studies in the fetal lamb model. We hope that the Vortex shunt may ultimately facilitate shunt deployment, reduce dislodgement risk, improve neonatal morbidity and mortality, and decrease the significant healthcare expenditures associated with long-term morbidity in LUTO survivors. In this manuscript, we review the natural history of LUTO, the risks and benefits of clinically available fetal shunts, and our development and early validation experiments.

Does prophylactic antibiotics post pediatric pyeloplasty reduce the incidence of febrile UTIs?

PURPOSE: The use of postoperative prophylactic antibiotics in pediatric upper urinary tract reconstruction remains controversial. In this study, we examined whether low dose antibiotics administered following pediatric pyeloplasty reduce the incidence of febrile urinary tract infections at our institution. As a secondary outcome, in those patients with infection, additional analysis was performed to better quantify which patient population benefits the most from low dose prophylactic antibiotics. METHODS: Institutional review board approval (IRB) was obtained. All methods were carried out in accordance with relevant guidelines and regulations. A retrospective study was performed in patients who underwent pyeloplasty (2011-2017) at our institution. Surgical approach (laparoscopic versus robotic assisted versus open, with or without internal JJ ureteral stent) were based on surgeon preference. Patients of 8 fellowship trained pediatric urologists were included in the study period. Patients with prior history of urologic interventions or other congenital genitourinary tract abnormalities were excluded. Demographics (age, gender, ethnicity, insurance status), prior history of culture proven urinary tract infection, surgical details (administration of perioperative antibiotics), and postoperative outcomes including; 1) re-admission 30 days post-surgery, 2) any urine cultures collected due to suspected urinary tract infection. RESULTS: A total of 209 patients (149 boys, 60 girls) met our inclusion criteria with 55/209 (26%) receiving postoperative prophylactic antibiotics. The average age was 6 years (range: 2 months-18 years). Indwelling ureteral stent was used in 176 (84%) patients. Eleven patients (5%) had a culture-proven urinary tract infection within 30-days postoperatively. No significant differences were seen in postoperative complications or incidence of urinary tract infection when comparing surgical approaches, +/- ureteral stent, or the use of antibiotics. Secondary analysis noted statistically significant increase in post-operative urinary tract infection in younger children (2.8 v. 6.2 years, p = 0.02), those patients who had a positive preoperative urine culture (8/11, p = 0.01) and those with public health insurance (p = 0.038). CONCLUSION: The incidence of postoperative urinary tract infection following pyeloplasty in our cohort was relatively low. There was a higher incidence of urinary tract infection in patients less than 3 years old. The use of antibiotics in patients post pyeloplasty did not appear to affect the incidence of post-operative urinary tract infection, however, they may have a role in children who have not yet potty trained and in patients with positive preoperative urine culture.

A magnetic hydrogel for the efficient retrieval of kidney stone fragments during ureteroscopy.

Only 60-75% of conventional kidney stone surgeries achieve complete stone-free status. Up to 30% of patients with residual fragments <2 mm in size experience subsequent stone-related complications. Here we demonstrate a stone retrieval technology in which fragments are rendered magnetizable with a magnetic hydrogel so that they can be easily retrieved with a simple magnetic tool. The magnetic hydrogel facilitates robust in vitro capture of stone fragments of clinically relevant sizes and compositions. The hydrogel components exhibit no cytotoxicity in cell culture and only superficial effects on ex vivo human urothelium and in vivo mouse bladders. Furthermore, the hydrogel demonstrates antimicrobial activity against common uropathogens on par with that of common antibiotics. By enabling the efficient retrieval of kidney stone fragments, our method can lead to improved stone-free rates and patient outcomes.

Factors of transurethral incision effectiveness for ureteroceles in pediatric patients: A 28-year, single-institution retrospective review.

BACKGROUND: As a congenital anomaly, ureteroceles occur in 1 in 4000 children, and are usually diagnosed prenatally. However, there remains a lack of definite consensus on the optimal management of congenital ureteroceles. OBJECTIVE: We evaluated factors associated with success of primary transurethral incision (TUI) in ureterocele pediatric patients. METHODS: Demographic and clinical information for 120 pediatric patients who were diagnosed with congenital ureterocele between 1993 and 2021 at our institution were obtained through retrospective chart review. Data were analyzed using Fisher's exact tests, t-tests, and logistic regression with a significance threshold of p < 0.05. The primary outcome of ureterocele management was TUI effectiveness, defined by no need for further surgical intervention. RESULTS: Of the 120 patients (39 boys, 81 girls) with ureteroceles, 75 patients (22 boys, 53 girls) met our inclusion criteria of undergoing initial TUI ureterocele. Initial TUI was effective in 51/75 patients (68.0%). We analyzed possible correlative factors for TUI efficacy. Simplex system was a significant predictor of primary TUI efficacy (85% effective in simplex systems, 62% in duplex systems). Prior urinary tract infection, prenatal diagnosis, and electrocautery technique were all associated with an increased risk of needing additional surgeries after primary TUI. DISCUSSION: The most significant predictors of effective primary TUI were simplex system and the absence of preoperative vesicoureteral reflux. Prenatal diagnosis, preoperative febrile urinary tract infection, higher preoperative hydronephrosis grade, and the use of electrocautery were all associated with decreased primary TUI efficacy. Study limitations include that it was a retrospective chart review, and cohort size was limited by incomplete urology follow-up and operative records. CONCLUSIONS: Initial TUI was an effective procedure for the majority of our pediatric ureterocele patients, a higher success rate compared to other cohorts. Patients with a simplex system were more likely to have an effective first TUI than patients with duplex systems, as were patients without preoperative reflux. Although not statistically significant, our data suggest prior UTI, prenatal diagnosis, higher preoperative hydronephrosis grade, and the use of electrocautery may be associated with having additional surgeries.

Optimizing Orthopaedic Trauma Implant Pricing Through a Data-Driven and Surgeon-Integrated Approach.

OBJECTIVE: To determine whether market-based pricing could be coupled with surgeon integration into negotiation strategies to achieve lower pricing levels for orthopaedic trauma implants. A secondary aim was to identify specific types of implants that may offer larger opportunities for cost savings. METHODS: Market pricing levels were reviewed from 2 industry implant databases. This information was used by surgeons and supply chain management at our institution to select appropriate target pricing levels (25th percentile) for commonly used orthopaedic trauma implants. Target price values were provided to the existing 12 vendors used by our institution with a clear expectation that vendors meet these thresholds. RESULTS: Benchmark modeling projected a potential savings of 20.0% over our prior annual spend on trauma implants. After 2 rounds of negotiation, savings amounted to 23.0% of prior annual spend. Total savings exceeded 1,000,000 USD with 11 of 12 vendors (91.7%) offering net savings. Total percent savings were highest for external fixators, drill bits, and K-wires. Plates and screws comprised the greatest proportion of our prior annual spend and achieved similar savings. CONCLUSION: A surgeon and supply chain coordinated effort led to major cost savings without a need for consolidation of vendors. LEVEL OF EVIDENCE: Economic Level IV. See Instructions for Authors for a complete description of levels of evidence.

A Stepwise Replicable Approach to Negotiating Value-driven Supply Chain Contracts for Orthobiologics.

INTRODUCTION: Orthobiologics are increasingly used to augment healing of tissues. Despite growing demand for orthobiologic products, many health systems do not enjoy substantial savings expected with high-volume purchases. The primary goal of this study was to evaluate an institutional program designed to (1) prioritize high-value orthobiologics and (2) incentivize vendor participation in value-driven contractual programs. METHODS: A three-step approach was used to reduce costs through optimization of orthobiologics supply chain. First, surgeons with orthobiologics expertise were engaged in key supply chain purchasing decisions. Second, eight orthobiologics formulary categories were defined. Capitated pricing expectations were established for each product category. Capitated pricing expectations were established for each product using institutional invoice data and market pricing data. In comparison with similar institutions, products offered by multiple vendors were priced at a lower benchmark (10th percentile of market price) than more rare products priced at the 25th percentile of the market price. Pricing expectations were transparent to vendors. Third, a competitive bidding process required vendors to submit pricing proposals for products. Clinicians and supply chain leaders jointly awarded contracts to vendors that met pricing expectations. RESULTS: Compared with our projected estimate of $423,946 savings using capitated product prices, our actual annual savings was $542,216. Seventy-nine percent of savings came from allograft products. Although the number of total vendors decreased from 14 to 11, each of the nine returning vendors received a larger, three-year institutional contract. Average pricing decreased across seven of the eight formulary categories. DISCUSSION: This study demonstrates a three-step replicable approach to increase institutional savings for orthobiologic products, engaging clinician experts, and strengthening relationships with select vendors. Vendor consolidation permits a symbiotic win-win relationship: Health systems achieve increased value by reducing unnecessary complexity of multiple contracts, and vendors obtain larger contracts with increased market share. LEVEL OF EVIDENCE: Level IV study.

Sociodemographic factors associated with Wilms tumor treatment and survival: a population-based study.

INTRODUCTION: Though Wilms tumor (WT) is one of the most common malignancies in children, there is a paucity of epidemiologic studies exploring sociodemographic disparities in treatment and survival. Here, we leveraged a national cancer registry to examine sociodemographic factors associated with receipt of adjuvant therapy, either chemotherapy or radiation, as well as overall survival among pediatric patients with WT. MATERIALS AND METHODS: Within the Surveillance Epidemiology and End Results database (2000-2016), we identified 2043 patients (≤ 20 years of age) with unilateral WT. Multivariable logistic regression and Cox proportional hazard models were constructed to examine the association of sociodemographic factors with, respectively, adjuvant chemotherapy/radiotherapy and overall survival (OS). RESULTS: Patients in the lowest SES quintile (OR 0.56, 95% CI 0.33-0.93, p = 0.03) were less likely to receive chemotherapy as compared to those in the highest SES quintile, though this association did not persist in sensitivity analyses including only patients at least 2 years of age and patients with regional/distant disease. In addition, female patients were more likely to receive chemotherapy (OR 1.46, 95% CI 1.08-1.97, p = 0.02) than male patients. Age, race, year of diagnosis, insurance status, and tumor laterality were not associated with receipt of chemotherapy. No sociodemographic variables were associated with receipt of radiotherapy. Lastly, as compared to Non-Hispanic-White patients, Hispanic patients had worse OS (HR 1.59, 95% CI 1.08-2.35, p = 0.02); no other sociodemographic variables were associated with OS. CONCLUSIONS: This study suggests multilevel sociodemographic disparities involving ethnicity and SES in WT treatment and survival.

Cost comparison of intra-detrusor injection of botulinum toxin versus augmentation cystoplasty for refractory neurogenic detrusor overactivity in children.

INTRODUCTION: Treatment options for refractory neurogenic detrusor overactivity (NDO) in children include botulinum toxin type A (BTX-A) and augmentation cystoplasty (AC). Although BTX-A is accepted in contemporary pediatric urologic practice, cost and long-term outcomes data for BTX-A are limited relative to the gold standard, AC. The purpose of this study was to compare the projected 10-year costs of AC versus BTX-A. METHODS: We performed a cost analysis from the payer perspective by computationally modeling treatment sequences by a Markov model. In the model, we used probabilities derived from published sources, and costs obtained at a tertiary medical center. The base case was a pediatric patient with refractory NDO. In the model, we assumed biannual BTX-A treatments. Treatment costs over 10 years were compared between immediate AC versus bridging therapy with BTX-A. Using the computational model, we simulated 100,000 instances of 10-year treatment cost for each of the two treatment modalities. The costs for the two treatment approaches were then compared using t-test and Wilcoxon test. RESULTS: The projected median and mean 10-year cost of immediately AC were $51,798.72 (95% CI [$51,798.72, $327,483.80]) and $123,473.4 (SD: $98,085.23) respectfully, while the projected median and mean 10-year cost of bridging therapy with BTX-A prior to proceeding to AC as needed were $74,552.46 (95% CI [$53,188.56, $309,913.07]) and $124,858.80 (SD: $84,495.35) (p < 0.001). CONCLUSIONS: For a typical index pediatric patient with NDO, bridging therapy with intravesical BTX-A is associated with an increased cost compared to immediate AC over a ten-year period.

Development and in-vitro characterization of a novel fetal vesicoamniotic shunt - The Vortex shunt.

OBJECTIVES: To develop and test a novel vesicoamniotic shunt (VAS) to treat fetal lower urinary tract obstruction (LUTO), decrease dislodgement and optimize shunt deployment in-vitro. METHODS: Vesicoamniotic shunt design objectives included: (1) robust and atraumatic fixation elements, (2) kink resistant conduit to adjust to fetal movement and growth, (3) one-way pressure valve to facilitate bladder cycling, and (4) echogenic deployment visualization aids. The force to dislodge the novel Vortex shunt was compared with existing commercially available shunts in a bench-top porcine bladder model. Sonographic echogenicity was evaluated with ultrasound-guided deployment, and the shunt valve pressure measured. RESULTS: A prototype novel Vortex shunt was developed using braided nitinol "umbrella-type" ends with a kink-resistant stem incorporating an internal one-way valve. The peak force required to dislodge the Vortex shunt was significantly higher than commercially available shunts (p < 0.01). Shunt deployment in the bench-top model was easily confirmed with ultrasound guidance and the brisk decompression of the inflated porcine bladder thereafter. In-vitro valve gauge pressure testing mirrored bladder pressures in human LUTO cases. CONCLUSION: In-vitro testing shows that the Vortex shunt may improve deployment, sonographic visualization, kink resistance, and dynamic size adjustment. Validation in preclinical animal models are warranted and currently underway.

The Value of Surgical Data-Impact on the Future of the Surgical Field.

The combination of computing power, connectivity, and big data has been touted as the future of innovation in many fields, including medicine. There has been a groundswell of companies developing tools for improving patient care utilizing healthcare data, but procedural specialties, like surgery, have lagged behind in benefitting from data-based innovations, given the lack of data that is well structured. While many companies are attempting to innovate in the surgical field, some have encountered difficulties around collecting surgical data, given its complex nature. As there is no standardized way in which to interact with healthcare systems to purchase these data, the authors attempt to characterize the various ways in which surgical data are collected and shared. By surveying and conducting interviews with various surgical technology companies, at least 3 different methods to collect surgical data were identified. From this information, the authors conclude that an attempt to outline best practices should be undertaken that benefits all stakeholders.

Telehealth Adoption Across Neurosurgical Subspecialties at a Single Academic Institution During the COVID-19 Pandemic.

OBJECTIVE: The COVID-19 pandemic has dramatically changed health care, forcing providers to adopt and implement telehealth technology to provide continuous care for their patients. Amid this rapid transition from in-person to remote visits, differences in telehealth utilization have arisen among neurosurgical subspecialties. In this study, we analyze the impact of telehealth on neurosurgical healthcare delivery during the COVID-19 pandemic at our institution and highlight differences in telehealth utilization across different neurosurgical subspecialties. METHODS: To quantify differences in telehealth utilization, we analyzed all outpatient neurosurgery visits at a single academic institution. Internal surveys were administered to neurosurgeons and to patients to determine both physician and patient satisfaction with telehealth visits. Patient Likelihood-to-Recommend Press-Ganey scores were also evaluated. RESULTS: There was a decrease in outpatient visits during the COVID-19 pandemic in all neurosurgical subspecialties. Telehealth adoption was higher in spine, tumor, and interventional pain than in functional, peripheral nerve, or vascular neurosurgery. Neurosurgeons agreed that telehealth was an efficient (92%) and effective (85%) methodology; however, they noted it was more difficult to evaluate and bond with patients. The majority of patients were satisfied with their video visits and would recommend video visits over in-person visits. CONCLUSIONS: During the COVID-19 pandemic, neurosurgical subspecialties varied in adoption of telehealth, which may be due to the specific nature of each subspecialty and their necessity to perform in-person evaluations. Telehealth visits will likely continue after the pandemic as they can improve clinical efficiency; overall, both patients and physicians are satisfied with health care delivery over video.

Deep learning enabled prediction of 5-year survival in pediatric genitourinary rhabdomyosarcoma.

BACKGROUND: Genitourinary rhabdomyosarcoma (GU-RMS) is a rare, pediatric malignancy originating from embryonic mesenchyme. Current approaches to prognostication rely upon conventional statistical methods such as Cox proportional hazards (CPH) models and have suboptimal predictive ability. Given the success of deep learning approaches in other specialties, we sought to develop and compare deep learning models with CPH models for the prediction of 5-year survival in pediatric GU-RMS patients. METHODS: Patients less than 20 years of age with GU-RMS were identified within the Surveillance, Epidemiology, and End Results (SEER) database (1998-2011). Deep neural networks (DNN) were trained and tested on an 80/20 split of the dataset in a 5-fold cross-validated fashion. Multivariable CPH models were developed in parallel. The primary outcomes were 5-year overall survival (OS) and disease-specific survival (DSS). Variables used for prediction were age, sex, race, primary site, histology, degree of tumor extension, tumor size, receipt of surgery, and receipt of radiation. Receiver operating characteristic curve analysis was conducted, and DNN models were tested for calibration. RESULTS: 277 patients were included. The area under the curve (AUC) for the DNN models was 0.93 for OS and 0.91 for DSS. AUC for the CPH models was 0.82 for OS and 0.84 for DSS. The DNN models were well-calibrated: OS model (slope = 1.02, intercept = -0.06) and DSS model (slope = 0.79, intercept = 0.21). CONCLUSIONS: A deep learning-based model demonstrated excellent performance, superior to that of CPH models, in the prediction of pediatric GU-RMS survival. Deep learning approaches may enable improved prognostication for patients with rare cancers.

Preoperative Bladder Bowel Dysfunction Is the Most Important Predictive Factor for Postoperative Urinary Retention After Robot-Assisted Laparoscopic Ureteral Reimplantation via An Extravesical Approach: A Multi-Center Study.

Introduction: Postoperative acute urinary retention (pAUR) is a known occurrence after robot-assisted laparoscopic ureteral reimplantation via an extravesical approach (RALUR-EV). We hypothesized that the risk factor of pAUR after RALUR-EV might be similar to that of pAUR after open reimplantation. We aimed at performing a retrospective multi-institutional study to evaluate the risk factors for pAUR after RALUR-EV. Materials and Methods: Perioperative data collected from two tertiary referral hospitals included demographics and perioperative variables such as bladder bowel dysfunction (BBD) status, vesicoureteral reflux (VUR) grade, and laterality. pAUR was defined as the need for urethral catheter replacement after removal of the initial postoperative catheter. Univariate and multivariate analyses were performed to identify risk factors for pAUR. Results: A total of 117 patients with 174 renal units from the 2 hospitals were enrolled in this study. The median age at the time of surgery was 5 (0.3-19) years. Bilateral RALUR-EV was performed in 57 (48.7%) cases. pAUR rate was 3.4% in all patients and 7.0% in 57 patients with bilateral VUR. All four cases of pAUR occurred after bilateral surgery. Univariate analysis showed age (p = 0.037), weight (p = 0.039), height (p = 0.040), and bilaterality (p = 0.037) as risk factors of pAUR. In a multivariate analysis, BBD was the only significant risk factor of pAUR (p = 0.037). Conclusion: Urinary retention after RALUR-EV occurred less frequently when compared with the previously reported open surgery series. pAUR was seen only in bilateral cases in our series. Preoperative history of BBD, but not male gender or length of surgical time, was the only risk factor of pAUR after RALUR-EV.

Robinow syndrome: Genital analysis, genetic heterogeneity, and associated psychological impact.

Robinow syndrome (RS) is a rare, pleiotropic genetic disorder. While it has been reported that males with Robinow syndrome may have genitourinary atypicalities, these have not been systematically studied. We hypothesized that the underlying gene involved plays a role in the clinical variability of associated genital findings and that the phenotypic appearance of the genitalia in RS may have a psychological impact. Urologic-specific examination consisted of detailed examination and a questionnaire to investigate the psychological impact of the genital phenotype. Nine males agreed to a full evaluation. Average age was 19.9 years, penile length was 32.5 mm, stretched length 53 mm, and width 24.4 mm. Penile transposition occurred in all 9 male who allowed full examination. Undescended testicles were noted in 4/10, testicular atrophy in 5/9, buried penis in 7/9, hypospadias in 5/8, and a large penopubic gap (space between dorsum of penis base and pubic bone) in 5/6. In this cohort, 78% answered our semi-quantitative pilot questionnaire that identified diminished sexuality, sexual function, and self-perception. In conclusion, RS has unique, hallmark genital findings including penile transposition, buried penis, undescended testes, and large penopubic gaps. Genital phenotype in males was not shown to correlate with the specific gene involved for each patient. Surgical approaches and other interventions should be studied to address the findings of decreased sexuality and self-perception. It is the authors' opinion that intervention to provide the appearance of penile lengthening be postponed until puberty to allow for maximal natural phallic growth.

Anterior urethral valves - A rare but challenging congenital pathology.

BACKGROUND: Anterior urethral valves (AUV) and associated anterior urethral diverticula (AUD) are a rare cause of congenital lower urinary tract obstruction. They occur 25-30 times less frequently than posterior urethral valves (PUV) and historically tend to have a less aggressive presentation and outcome. However, due to the low incidence, little is known about management and long-term prognosis. OBJECTIVE: We aim to evaluate the outcomes after AUV valve ablation and compare this group to a previously studied PUV cohort. STUDY DESIGN: In this IRB-approved study, we retrospectively identified all patients from 2002 to 2017 undergoing valve ablation using CPT code 52400. Charts were manually reviewed to identify AUV patients, their presenting symptoms, timing of diagnosis, pre and postnatal imaging findings, age at presentation and valve ablation, creatinine, recurrences, additional surgeries and follow-up. The AUV group was then compared to a previously studied PUV cohort of 104 patients from our institution. RESULTS: Nine AUV patients were identified. Only four (44%) patients were diagnosed prenatally. Three (33%) patients were diagnosed neonatally, one for weak stream/dribbling and two for febrile UTIs. The remaining two patients were diagnosed at ages 3 and 4 due to dysuria and penile swelling with micturition. Patients presenting later in life had no evidence of renal dysfunction or VUR. All patients underwent primary TUR-AUV (1 laser, 4 cold knife, 4 cautery), but 55% had residual valves and/or diverticula identified on routine postoperative imaging in two patients and due to development of clinic symptoms in three patients. All five patients with recurrences underwent repeat endoscopic evaluation, and thereafter two patients required urethral reconstruction. In contrast, only 15% (16/104) of PUV patients required re-TUR (p = 0.01). At an average follow-up time of 4.24 years (range 0.6-11.4 years), 44% of patients had no evidence of CKD, and two patients (22%) had progressed to CKD of at least stage IIIA, compared to 21.4% in the PUV cohort at a mean follow-up of 2.3 years. DISCUSSION: The overall incidence of AUV is low, making it difficult to characterize these patients definitively. However, despite a milder phenotype and later presentation in most AUV patients, they do require more aggressive surgical treatment for complete resolution of the AUV. Furthermore, the long-term renal outcomes appear more severe than previously reported. CONCLUSIONS: The poorer outcomes of AUV patients both with respect to recurrence and long-term CKD indicate that close urologic follow-up is essential in this group.

Quantifying the forces needed for ureteral stent removal: Initial evaluation of magnetic stent removal devices on benchtop and porcine models.

BACKGROUND: Indwelling ureteral stents are commonly used in pediatric surgeries for kidney stones and urinary tract obstruction, but often require instrumentation or anesthesia for removal. We evaluated the use of novel magnet devices to remove indwelling ureteral stents with a distally attached magnetic bead. Since the forces required for stent removal are unknown, we aimed to characterize and quantify the forces required for stent removal for future prototype testing. METHODS: A custom 3-D urinary tract model was used for benchtop testing, and 6 female porcine subjects were used for in vivo testing after obtaining institutional approval. A modified porcine urethral model that patterned the human female urethral anatomy with approximately 4.5 cm urethral length was used. A HF-10 digital force gauge measured the force required to remove stents with varying properties (stent size, presence of curl, and size of distal magnetic bead). These force measurements were compared to the quantified magnetic forces generated by external magnets and catheter tip magnets. Furthermore, the magnetic retrieval devices were tested with various magnetic beads on both benchtop and porcine models. RESULTS: The required force for removal of a 5 Fr x 14 cm double J stent was significantly higher in the benchtop model compared to the porcine model (4.7N v. 0.8N, p < 0.001). Forces of at least 1N were required from the external magnets to move the stent and bead across a 4-5 cm distance from the bladder neck to the urethral meatus. External magnets at a distance of 4-5 cm produced insufficient forces for removal, and thus they failed to remove the magnetic bead and stent from the bladder. The catheter-based retrieval device showed better success with a variety of different magnet pairs on the retrieval device and stent. Furthermore, the addition of saline to the bladder allowed for better retrieval rates of the smallest beads, even by the smallest magnetic tip catheters. CONCLUSIONS: The forces required for ureteral stent removal are <1N in the porcine model, and improved benchtop models that emulate such parameters will facilitate future stent removal device testing. Given this threshold, external magnets did not generate sufficient force for stent removal at the required distance of 4-5 cm, whereas catheter tip magnetic retrieval overcomes the minimum distance limitation and showed successful retrieval. While these results are encouraging, further studies will define the optimal combination of catheter magnetic tip size and stent magnetic bead size.

Does de novo hydronephrosis after pediatric robot-assisted laparoscopic ureteral re-implantation behave similarly to open re-implantation?

BACKGROUND: While open ureteral re-implantation surgery is the gold standard for surgical correction of vesicoureteral reflux (VUR), robot-assisted laparoscopic ureteral re-implantation via an extravesical approach (RALUR-EV) has become a minimally invasive alternative. Previous studies have shown that transient hydronephrosis after open re-implantation can occur in up to 28% of patients. However, previous studies have also shown that de novo hydronephrosis after open re-implantation is not predictive of final differential renal function. OBJECTIVE: A retrospective review was performed to characterize the natural history of postoperative hydronephrosis after RALUR-EV for primary VUR in pediatric patients. STUDY DESIGN: A retrospective chart review of a single-surgeon series was performed for pediatric patients who underwent RALUR-EV for primary VUR. The severity of de novo hydronephrosis was assessed using the Society for Fetal Urology (SFU) grading system via renal ultrasound at the 1-month postoperative follow-up. Renal ultrasound was performed at least every six months. Radiographic success was defined as complete resolution of VUR on the voiding cystourethrogram at the 4-month mark. Patient demographics, surgery duration, length of hospital stay, pre-operative and postoperative VUR grades, and follow-up time periods were collected. Patients with other associated urinary pathology and patients lost to follow-up were excluded from the study. RESULTS: A total of 87 patients (121 kidney units) with primary VUR who underwent RALUR-EV met the inclusion criteria. SFU grade 1-3 hydronephrosis was noted in 30.3% (36/119) of kidney units at the 1-month mark, but 83.9% (26/31) cases with hydronephrosis completely resolved in a median time of 7.9 months (range: 3.4-21.0 months), and all four cases with unresolved hydronephrosis were downgraded to SFU grade 1 without the need for intervention. DISCUSSION: A radiographic success rate of 96% was demonstrated in this cohort, which is comparable with that of historical open re-implantation series. A similar rate of de novo hydronephrosis was also noted in this cohort when compared with that of previous open re-implantation series, but de novo hydronephrosis after RALUR-EV had a similar or more rapid resolution rate than that previously reported after open intravesical and extravesical re-implantation series. CONCLUSION: De novo hydronephrosis after RALUR-EV behaves similarly to de novo hydronephrosis after open ureteral re-implantation, where de novo hydronephrosis is present in up to 30% of pediatric patients who underwent RALUR-EV. The hydronephrosis self-resolves without the need for intervention in the overwhelming majority of cases and resolves at a median time of 7.9 months after surgery.

The Future of Robotic Surgery in Pediatric Urology: Upcoming Technology and Evolution Within the Field.

Since the introduction of the Da Vinci Surgical System (Intuitive Surgical, Inc., Sunnyvale, CA) in 1999, the market for robot assisted laparoscopic surgery has grown with urology. The initial surgical advantage seen in adults was for robotic prostatectomy, and over time this expanded to the pediatric population with robotic pyeloplasty. The introduction of three-dimensional visualization, tremor elimination, a 4th arm, and 7-degree range of motion allowed a significant operator advantage over laparoscopy, especially for anastomotic suturing. After starting with pyeloplasty, the use of robotic technology with pediatric urology has expanded to include ureteral reimplantation and even more complex reconstructive procedures, such as enterocystoplasty, appendicovesicostomy, and bladder neck reconstruction. However, limitations of the Da Vinci Surgical Systems still exist despite its continued technological advances over multiple generations in the past 20 years. Due to the smaller pediatric market, less focus appears to have been placed on the development of the smaller 5 mm instruments. As pediatric urology continues to utilize robotic technology for minimally invasive surgery, there is hope that additional pediatric-friendly instruments and components will be developed, either by Intuitive Surgical or one of the new robotic platforms in development that are working to address many of the shortcomings of current systems. These new robotic platforms include improved haptic feedback systems, flexible scopes, easier maneuverability, and even adaptive machine learning concepts to bring robotic assisted laparoscopic surgery to the next level. In this report, we review the present and upcoming technological advances of the current Da Vinci surgical systems as well as various new robotic platforms, each offering a unique set of technological advantages. As technology progresses, the understanding of and access to these new robotic platforms will help guide pediatric urologists into the next forefront of minimally invasive surgery.