Pelvic Neuroblastoma of the Pediatric Prostate

Neuroblastoma accounts for a significant portion of childhood tumors and can present in a variety of ways. Pelvic neuroblastoma has been reported but few cases exist of neuroblastoma invading or originating from the bladder or prostate. We present a 4-year-old patient with pelvic neuroblastoma arising from the prostate and describe the medical and surgical management of this challenging case. While pelvic neuroblastoma may have an improved prognosis, this case demonstrates the challenging surgical decisions that accompany these patients to maintain quality of life while balancing oncologic efficacy of treatment.

Survey of COVID-19 impact on pediatric urology services

INTRODUCTION

To better understand how the COVID-19 pandemic has forced rapid operational changes in the global healthcare industry, changes implemented on an individual, institutional basis must be considered. There currently is not adequate literature about the overall impact COVID-19 has had on pediatric urology services worldwide. We believe that they have dramatically decreased during the COVID-19 crisis, but have adapted to accommodate changes. We hypothesize that patient care was widely variant due to inadequate standardized recommendations or crisis planning.

MATERIALS AND METHODS

A web-based survey was deployed to 377 pediatric urologists globally via email to analyze COVID-19's impact on various types of pediatric urology practices. Key categories included impacts on elective services, telemedicine use, finances, and recovery operations. A total of 114 responses were collected between April 29th - May 22nd, 2020.

RESULTS

The widespread cancellation of elective surgical procedures caused significant disturbances in the field. There was a uniform, significant increase (75%) in telemedicine use across practices. The pandemic has created many changes in care provision for physicians, institutions, and patients themselves. Furthermore, the sudden economic burden on healthcare facilities could lead to cost-cutting measures, creating further strain within institutions. Though telemedicine has its limitations, it is a very viable option when traditional services are unavailable.

CONCLUSIONS

Immediate steps should be taken to ensure that the recovery phases of pediatric urology practices are as efficient as possible. Institutions should develop task forces to develop critical workflow processes in the event of health crises, while still maintaining patient-centered care. This will be essential in maximizing appropriate care allocation.

Trends in Urologic Indications for Pediatric Renal Transplantation Over a 27-Year-period United Network for Organ Sharing (UNOS) Database

OBJECTIVE

To elucidate the trends in urologic causes for renal transplant in the pediatric population using a national database. Little is known about the specific pediatric urologic conditions and resultant trends that precede renal transplantation.

MATERIAL AND METHODS

We reviewed the United Network for Organ Sharing (UNOS) database for pediatric patients (<18 years old) who underwent renal transplantation from January 1988 to September 2015. We included those patients who received a renal transplant because of a urologic condition.

RESULTS

Over 27 years, 7291 of 20,213 children (36%) underwent renal transplant secondary to a urologic condition. The 2 most common indications were hypoplasia/dysplasia/dysgenesis/agenesis (HDDA, 35.1%) and congenital obstructive uropathy (COU, 25.7%). The incidence of COU has increased from 18% to 30%, and the incidence of Wilms tumor has remained relatively consistent at 1.8% per year. In addition, 68% of all urologic renal transplants were performed in men compared with women. However, a higher percentage of women required transplantation because of Wilms tumor (3.1% vs 1.2%) and chronic pyelonephritis (17.6% vs 7.9%). Overall, the majority of patients (61.5%) who underwent renal transplantation were white, 18.8% Hispanic, and 15.3% black.

CONCLUSION

HDDA and COU consistently have been the most common urologic indications for renal transplantation. Both are the leading causes in men, whereas HDDA and chronic pyelonephritis are predominant in women. Higher rate of renal transplant during the ages of 11-17 years is suggestive of increased burden on poorly functioning kidneys during times of adolescent growth.

Bowel preparation prior to reconstructive urologic surgery in pediatric myelomeningocele patients

INTRODUCTION

Mechanical bowel preparation (MBP) has historically been the standard of care for patients undergoing reconstructive urologic surgery, including urinary diversion. To date, several studies have examined the role of mechanical bowel preparation in postoperative outcomes in pediatric patients undergoing augmentation cystoplasty. However, these patient populations have been heterogeneous in nature, with no studies dedicated to examining the role of MBP prior to reconstructive urologic surgery in pediatric patients with myelomenginoceles. Thus, our objective was to retrospectively assess perioperative measures and postoperative complications after reconstructive urologic surgery with or without mechanical bowel preparation in pediatric myelomeningocele patients.

MATERIALS AND METHODS

From 2008 to 2013, 80 patients with myelomeningocele underwent reconstructive urologic surgery involving the use of bowel. Seventy patients underwent a preoperative MBP while 10 did not. Perioperative measures and postoperative complications for these two cohorts were assessed.

RESULTS

Eighty patients with myelomeningocele were identified; 70 patients underwent MBP while 10 patients did not. There were no statistically significant differences in demographics or operative time. There were no statistically significant differences in postoperative outcomes including time to first bowel movement and time to tolerating diet. There was also no significant difference in overall complication rate; patients with MBP had 31/70 (44%) complications while 2/10 (20%) of those without MBP had complications (p = 0.18).

CONCLUSION

There was no significant difference in perioperative measures and postoperative complications for patients who did not receive a mechanical bowel preparation. Our findings indicate that it is safe and warranted to perform a prospective, randomized study to better characterize the risks and benefits of preoperative bowel preparation for patients with myelomeningocele.

Combination of Extracorporeal Shockwave Lithotripsy and Ureteroscopy for Large Staghorn Calculi in a Pediatric Patient: Case Report

Background: Extracorporeal shockwave lithotripsy (SWL) is a procedure commonly performed to treat nephrolithiasis, with promising results in pediatric patients. However, increasing renal calculi size is directly related to worsening stone-free rates. There are few reports in the literature of >2-cm staghorn calculi that expound on the exact mechanism of treatment in the pediatric population. Case Presentation: We present a case report of a 3-year-old boy who presented with a large 3-cm staghorn calculi effectively treated with one session of SWL followed by a planned staged ureteroscopy for definitive treatment. Conclusion: Despite the numerous studies limiting the use of SWL to treat stones <2 cm, if used in softer composition stones, coupled with the larger focal volume involved with smaller patients, SWL when used in combination with adjunctive ureteroscopy is a safe and effective treatment option.

Optimal Length of Follow-up for the Detection of Unsuccessful Pediatric Pyeloplasty: A Single-Center Experience

OBJECTIVES

To assess the optimal length of follow-up for patients undergoing both open and minimally invasive pyeloplasties to ensure prompt detection of a recurrent obstruction. There are no standard guidelines on ideal follow-up and imaging post-pediatric pyeloplasty currently.

METHODS

A retrospective chart review identified 264 patients (<18 years old) who underwent pyeloplasty for ureteropelvic junction obstruction between April 2002 and December 2014. Ultrasound was obtained every 3-4 months for the first year following pyeloplasty and thereafter at discretion of treating physician. Patient characteristics including symptoms and imaging were reviewed.

RESULTS

Of the 264 patients, 72% were male with mean age of 51 months and follow-up of 26.8 months. Approximately 73% followed up to 3 years. Fourteen patients (5.3%) had a recurrent obstruction. Among the failures, 85% were diagnosed and underwent successful redo pyeloplasty within 3 years. Six infants had a recurrence (43% of all unsuccessful surgeries) and were diagnosed within 3 years of the initial surgery. Patients undergoing a minimally invasive procedure were less likely to be followed for more than 3 years compared to an open procedure (p < 0.001). Patients with severe hydronephrosis preoperatively were followed longer (p = 0.031). Age at surgery and type of surgical approach (p < 0.01) were significant predictors of length of follow-up in a negative binomial regression.

CONCLUSION

Based on the results, a minimum of 3 years of follow-up is necessary to detect the majority of recurrent obstructions. Those patients who have higher than average lengths of follow-up tend to be younger and/or underwent an open surgical approach.

The use of intraoperative cell salvage in urologic oncology

Intraoperative cell salvage (IOCS) has been used in urologic surgery for over 20 years to manage intraoperative blood loss and effectively minimize the need for allogenic blood transfusion. Concerns about viability of transfused erythrocytes and potential dissemination of malignant cells have been addressed in the urologic literature. We present a comprehensive review of the use of IOCS in urologic oncologic surgery. IOCS has been shown to preserve the integrity of erythrocytes during processing and effectively provides cell filtration to mitigate the risk of tumor dissemination. Its use is associated with reduction in the overall need for allogenic blood transfusion, which clinically reduces the risk of hypersensitivity reactions and disease transmission, and may have important implications on overall oncologic outcomes. In the context of a variety of urologic malignancies, including prostate, urothelial, and renal cancer, the use of IOCS appears to be safe, without risk of tumor spread leading to metastatic disease or differences in cancer-specific and overall survival. IOCS has been shown to be an effective intraoperative blood management strategy that appears safe for use in urologic oncology surgery. The ability to reduce the need for additional allogenic blood transfusion may have significant impact on immune-mediated oncologic outcomes.

Predicting Spontaneous Stone Passage in Prepubertal Children: A Single Institution Cohort

INTRODUCTION

No method currently exists for predicting which young child with a renal or ureteral stone will require surgery as opposed to pass the stone. Our goals were to analyze practice patterns at a major pediatric center and to identify factors that predicted spontaneous stone passage.

METHOD

A retrospective review of all prepubertal patients (≤ 11 years) presenting to our institution from January 2005 to July 2014 with symptomatic nephrolithiasis was performed. Demographic data and stone details were reviewed, including anatomic location, size, and outcomes. Spontaneous stone passage was determined by parental report and/or stone absence on imaging obtained within 6 months after initial diagnosis.

RESULTS

A total of 119 eligible patients were identified, with an average age of 88.7 months (4-143). Forty eight (40.3%) patients spontaneously passed their stone and the remaining 59.7% required endoscopic intervention. Overall, 79.0% had symptomatic presentation (flank pain, hematuria) and 39.5% of patients were obstructing stones. Symptomatic presentation was more common with ureteral (86.5%) than with renal (66.7%) stones, but was not associated with increased passage of stones in general (p-value 0.1765). Of the 48 patients who spontaneously passed stones, 11 (24.4%) were renal stones compared with 37 (50.0%) ureteral stones. The average size of spontaneously passed stones was 3.5 mm (2-8) for renal and 3.4 mm (1-7) for ureteral stones. Based on logistic regression, the single most important predictor of stone passage was stone size (p-value <0.001). The odds of passage were 3.1 times higher for ureteral stones compared with renal stones (p = 0.0070) when not controlling for size.

CONCLUSION

In prepubertal patients, ureteral stones with an average size of 3.5 mm or less are more likely to pass spontaneously. Based on this information, watchful waiting is a reasonable option in clinically stable nonseptic patients with renal/ureteral stones of this size.

Contemporary Series of Robotic-Assisted Distal Ureteral Reconstruction Utilizing Side Docking Position

Purpose:

The robot-assisted approach to distal ureteral reconstruction is increasingly utilized. Traditionally, the robot is docked between the legs in lithotomy position resulting in limited bladder access for stent placement. We examined the use of side docking of the daVinci robot® to perform distal ureteral reconstruction.

Materials and Methods:

A retrospective review of distal ureteral reconstruction (ureteral reimplantation and uretero-ureterostomy) executed robotically was performed at a single institution by a single surgeon. The daVinci robotic® Si surgical platform was positioned at the right side of the patient facing towards the head of the patient, i.e. side docking.

Results:

A total of 14 cases were identified from 2011–2013. Nine patients underwent ureteral reimplantation for ureteral injury, two for vesicoureteral reflux, one for ureteral stricture, and one for megaureter. One patient had an uretero-ureterostomy for a distal stricture. Three patients required a Boari flap due to extensive ureteral injury. Mean operative time was 286 minutes (189–364), mean estimated blood loss was 40cc (10–200), and mean length of stay was 2.3 days (1–4). Follow-up renal ultrasound was available for review in 10/14 patients and revealed no long-term complications in any patient. Mean follow-up was 20.7 months (0.1–59.3).

Conclusion:

Robot-assisted laparoscopic distal ureteral reconstruction is safe and effective. Side docking of the robot allows ready access to the perineum and acceptable placement of the robot to successfully complete ureteral repair.

Evolving Mechanisms of Injury and Management of Pediatric Blunt Renal Trauma--20 Years of Experience

OBJECTIVE

To review 20 years of a prospectively maintained trauma database to identify changing trends in mechanisms of renal injury, demographics, and management outcomes.

MATERIALS AND METHODS

Following the approval from the institutional review board, a prospectively maintained trauma database was reviewed for renal trauma patient demographics, management, and mechanisms of injury. Data were reviewed first for the entire cohort and then incrementally to identify mechanisms of injury associated with increasing frequency or grade of injury.

RESULTS

A total of 228 graded renal injuries were identified from 1993 to 2013. The majority of renal injuries occurred in males (77.2%) >6 years of age (85.1%). Low grade (I-III) injuries were more common (70.6%). The most frequent mechanisms of injury identified were falls, recreational motor vehicle (RMV) accidents, bike accidents, motor vehicle collisions, and sports accidents, in descending order of frequency. RMV-related injuries have become frequent with time despite recommendations against use in the pediatric age population. Surgical intervention was rarely necessary. Over the 20 year study period, 5 nephrectomies (1.4%) were required, whereas 10 endoscopic interventions or percutaneous drainage procedures were needed (2.4%).

CONCLUSION

The majority of blunt pediatric renal injuries are low grade and can be managed nonoperatively. Nephrectomy is rarely required but is indicated for hemodynamic instability refractory to resuscitation. Pediatric blunt renal trauma secondary to RMV use is increasing despite recommendations against their use in the pediatric population.

Outcomes of Ureteroscopic Management of Pediatric Urolithiasis: A Comparative Analysis of Prepubertal and Adolescent Patients

OBJECTIVE

To compare the outcomes of ureteroscopic intervention in terms of both the stone-free rate and complications in both prepubertal and adolescent patients. Although safety of pediatric ureteroscopic intervention is well established, a comparative outcome of prepubertal and adolescent patients is lacking.

MATERIALS AND METHODS

Pediatric patients who underwent ureteroscopic treatment of a renal or ureteral stone at our institution from July 2005 to August 2014 were retrospectively identified. Patients were classified by age either as prepubertal (≤11 years) or adolescent (>11 years) for purposes of comparison. Demographic and intraoperative variables as well as 30-day postoperative complication rates were compared between groups. Data were analyzed using χ(2) and Fisher's exact tests as appropriate.

RESULTS

A total of 104 patients were identified, of whom 64 (62%) were prepubertal and 40 (38%) were adolescent. Ureteroscopic failure occurred in a minority of patients (5% vs 4.7%, P > .9). Complication rates including ureteral perforation (0% vs 1.6%, P > .9), postoperative urinary tract infection (2.5% vs 4.7%, P > .9), hematuria with clot passage (0% vs 7.8%, P = .15), and persistent flank pain (15% vs 17%, P = .85) were not significantly different between adolescent and prepubertal patients, respectively.

CONCLUSION

In spite of small size and small body habitus, the ureteroscopic management of pediatric urolithiasis can be performed successfully in both the prepubertal and adolescent patients with acceptable and equivalent morbidity as well as successful clearance of stone.

Tracking of radiation exposure in pediatric stone patients: The time is now

BACKGROUND

Despite the increasing incidence of pediatric nephrolithiasis, there is little data quantifying the radiation exposure associated with treatment of this disease. In this study, pediatric patients with nephrolithiasis who were managed at a single institution were identified, and the average fluoroscopy time and estimated radiation exposure associated with their procedures were reported.

METHODS

Stone procedures performed on pediatric patients between 2005 and 2012 were retrospectively identified. Procedures were classified as primary ureteroscopy (URS), stent placement prior to ureteroscopy (SURS), percutaneous nephrolithotomy (PCNL), and bilateral ureteroscopy (BLURS). Patient demographic information, stone size, stone location, number of radiographic images, and fluoroscopy times were analyzed.

RESULTS

A total of 152 stone procedures were included in the final analysis (92 URS, 38 SURS, eight BLURS and 14 PCNL). Mean patient age at time of stone treatment was 15.94 ± 4.1 years. Median fluoroscopy times were 1.6 (IQR 0.8-2.4), 2.1 (IQR 1.6-3.0), 2.5 (IQR 2.0-2.9), and 11.7 (IQR 5.0-18.5) minutes for URS, SURS, BLURS and PCNL, respectively. There was a moderate correlation between stone size and fluoroscopy time (r = 0.33). When compared with ureteroscopic procedures, PCNL was associated with a significantly higher fluoroscopy time (11.7 vs 2.1 min, P < 0.001). The estimated median effective dose was 3 mSv for ureteroscopic procedures and 16.8 mSv for PCNL. In addition to radiation exposure during treatment, patients in this cohort were exposed to an average of one (IQR1-3) CT scan and three (IQR 1-8) abdominal X-rays. No new malignancies were identified during the limited follow-up period.

CONCLUSIONS

Radiation exposure during treatment of pediatric stone disease is not trivial, and is significantly greater when PCNL is performed. Given the recommended maximum effective dose of 50 mSv in any one year, urologists should closely monitor the amount of fluoroscopy used, and consider the potential for radiation exposure when choosing the operative approach. Prospective studies are currently underway to elucidate precise dose measurements and localize sites of radiation exposure in children during stone treatment.

Resonance metallic stents do not effectively relieve extrinsic ureteral compression in pediatric patients

BACKGROUND AND PURPOSE

Use of metallic stents (Resonance) has been reported in the literature to be effective in relieving extrinsic obstruction in adults. Successful patency rates have been reported to be around 83.3%. The use of Resonance stents in children has not been reported. We present our experience with these stents in addressing extrinsic ureteral obstruction in the pediatric population.

PATIENTS AND METHODS

We identified two patients who underwent placement of Resonance stents for extrinsic compression at the Children's Hospital of the University of Pittsburgh Medical Center. The first patient is a 12-year-old girl with a solitary left kidney who had a diagnosis of pelvic rhabdomyosarcoma; she was treated with surgery followed by adjuvant chemoradiation. Two years post-treatment, worsening renal function secondary to ureteral strictures developed. The second patient is a 14-year-old girl with a history of Gardner syndrome. Recurrent desmoid tumors developed in her pelvis and retroperitoneum that led to right ureteral obstruction, necessitating a nephrostomy tube.

RESULTS

Both patients underwent successful technical placement of a Resonance stent. The time to failure for patient 1 was 3 months and for patient 2, 3 weeks. The first patient presented to the emergency department 3 months poststent in renal failure with a creatinine level of 13.7 mg/dL. This necessitated nephrostomy tube placement and hemodialysis. Ultimately, she needed an ileal ureter to preserve renal function. She is off hemodialysis and has a creatinine level of 2.2 mg/dL.The second patient, recurrent episodes of pyelonephritis, worsening hydronephrosis, and flank pain developed with just the Resonance stent in place. It was elected to remove the Resonance stent and replace the nephrostomy tube. She needed extensive ureterolysis, a right subtotal ureterectomy with a right to left ureteroureterostomy.

CONCLUSION

We did not find the use of these stents to be effective in children. The time to failure was significantly shorter in children than those reported in the literature for adults.

Advances in the surgical pediatric urologic armamentarium

The surgical armamentarium of the pediatric urologist has changed greatly in the past 2 decades on account of new technology and careful adaptation of minimally invasive techniques in children. Conventional laparoscopy, robotic-assisted laparoscopy, laparoendoscopic single-site surgery, and endourologic surgery have, to varying degrees, provided new approaches to urologic surgery in the pediatric population. This article reviews the technology and adaptations behind these recent advances as well as their current applications in management of urologic disease in children.

Pediatric laparoscopic and robot-assisted laparoscopic surgery: technical considerations

Laparoscopy has become an effective modality for the treatment of many pediatric urologic conditions that need both extirpative and reconstructive techniques. Laparoscopic procedures for urologic diseases in children, such as pyeloplasty, orchiopexy, nephrectomy, and bladder augmentation, have proven to be safe and effective with outcomes comparable to those of open techniques. Given the steep learning curve and technical difficulty of laparoscopic surgery, robot-assisted laparoscopic surgery (RAS) is increasingly being adopted in pediatric patients worldwide. Anything that can be performed laparoscopically in adults can be extended into pediatric practice with minor technical refinements. We review the role of laparoscopic and RAS in pediatric urology and provide technical considerations necessary to perform minimally invasive surgery successfully.

Incidentally discovered capillary hemangioma of the prostate

We present the case of a 69-year-old male with incidentally discovered capillary hemangiomas at radical prostatectomy. Hemangiomas of genitourinary origin are extremely rare, typically benign vascular tumors. This finding represents the first reported hemangioma within a radical prostatectomy specimen.

The evolution of the endourologic management of pediatric stone disease

In the 1980s, the advent of shock wave lithotripsy (SWL) revolutionized pediatric stone management and is currently the procedure of choice in treating most upper tract calculi <1.5 cm in children. However, with miniaturization of instruments and refinement of surgical technique the management of pediatric stone disease has undergone a dramatic evolution over the past twenty years. In a growing number of centers, ureteroscopy (URS) is now being performed in cases that previously would have been treated with SWL or percutaneous nephrolithotomy (PCNL). PCNL has replaced open surgical techniques for the treatment of large stone burdens >2 cm with efficacy and complication rates similar to the adult population. Recent results of retrospective reviews of large single institution series demonstrate stone free and complication rates with URS comparable to PCNL and SWL but concerns remain with these techniques regarding renal development and damage to the pediatric urinary tract. Randomized controlled trials comparing the efficacy of SWL and URS for upper tract stone burden are needed to reach consensus regarding the most effective primary treatment modality in children. This report provides a comprehensive review of the literature evaluating the indications, techniques, complications, and efficacy of endourologic stone management in children.

Real-time tomographic reflection in facilitating percutaneous access to the renal collecting system

BACKGROUND AND PURPOSE

Real-time tomographic reflection is a novel technique that uses a geometrically fixed arrangement of a conventional ultrasound transducer, a transducer-incorporated monitor, and a half-silvered mirror. This device, dubbed the Sonic Flashlight, generates a virtual anatomically scaled image, obviating the need for a separate monitor. It may therefore facilitate invasive procedures, such as percutaneous access to the kidney. This proof-of-concept study assesses the feasibility of this technique for renal imaging and concomitant needle puncture guidance.

MATERIALS AND METHODS

In a swine model with induced hydronephrosis, the Sonic Flashlight was used to visualize and guide needle access to the renal pelvis. Passage of a 7-inch, 18-gauge spinal needle was performed. Entry into the collecting system was confirmed by the aspiration of urine.

RESULTS

The anechoic renal pelvis and hyperechoic needle tip could be seen with the Sonic Flashlight device. Successful access to the collecting system was obtained twice without dificulty. The sonographic image, appearing to emanate from the tip of the transducer, makes visualization and manipulation more intuitive. Furthermore, by placing the operator's eyes and hands in the same field as the sonogram, image-guided procedures are potentially easier to learn.

CONCLUSION

The relatively shallow depth of penetration of the current device limits its clinical usefulness. A new Sonic Flashlight with a greater depth of penetration is in development.

Management of urine leak after laparoscopic cyst decortication with retrograde endoscopic fibrin glue application and ureteral stent placement

Urine leakage is an uncommon complication after renal cyst decortication that typically resolves with adequate drainage. With prolonged large volume urine leakage from a perinephric drain, however, consideration for open surgical repair must be taken into account. We present the successful management of persistent urine leakage after laparoscopic cyst decortication with endoscopic retrograde fibrin glue injection and ureteral stent placement.

Contemporary surgical management of pediatric urolithiasis

With miniaturization of instruments and refinement of surgical technique, the management of pediatric stone disease has undergone a dramatic evolution. While shock wave lithotripsy (SWL) is still commonly used to treat upper tract calculi, the use of ureteroscopy (URS) has dramatically increased and is now the procedure of choice for upper tract stone burdens less than 1.5cm at centers with significant experience. Percutaneous nephrolithotomy (PCNL) has replaced open surgical techniques for the treatment of large stone burdens greater than 2cm, with efficacy and complication rates similar to the adult population. Large institutional series demonstrate comparable stone-free and complication rates with SWL, URS, and PCNL, but concerns remain with these techniques regarding renal development and damage to the pediatric urinary tract. Randomized controlled trials comparing the efficacy of SWL and URS for upper tract stone burdens are needed to reach consensus regarding the most effective primary treatment modality in children.

Evolution of laparoscopy in pediatric urology

The use of laparoscopy has evolved over the last 30 years, particularly in the last decade, from merely extirpative or diagnostic procedures to intricate reconstructive procedures on the major genitourinary organs. The development of laparoscopy as a method of treating urological problems has progressed more slowly in children compared with adults; perhaps due to the availability of miniaturized technology, the steep learning curve and the high success of traditional open surgery. This article seeks to provide a comprehensive review of the evolution of laparoscopy from its inception to its present-day applications in the field of pediatric urology, including the current indications and results of various laparoscopic procedures.

Needle steering system using duty-cycled rotation for percutaneous kidney access

The authors present ongoing work on the use of a variable curvature flexible needle steering system to gain percutaneous access to the kidney for medical interventions. A nonlinear control law is introduced which drives the needle to track a predetermined planar path using a steering approach based on duty-cycled rotation during insertion. Renal access is performed in simulation and tested in vitro in a tissue phantom to validate the proposed control method.

Endourological management of pediatric stone disease: present status

PURPOSE

The incidence of nephrolithiasis in the pediatric population has been steadily increasing. The miniaturization of endoscopic instruments and improvement in imaging modalities have facilitated safe and effective endourological treatment in this patient population. We reviewed the current status of pediatric stone disease management.

MATERIALS AND METHODS

A comprehensive literature review was performed using MEDLINE/PubMed to evaluate the indications, techniques, complications and efficacy of endourological stone management in children.

RESULTS

In the 1980s shock wave lithotripsy revolutionized stone management in children, becoming the procedure of choice for treating upper tract calculi less than 1.5 cm. Percutaneous nephrolithotomy has replaced open surgical techniques for the treatment of stone burdens greater than 1.5 cm with efficacy and complication rates mirroring those in the adult population. However, at an increasing number of centers ureteroscopy is now being performed in cases that previously would have been treated with shock wave lithotripsy or percutaneous nephrolithotomy. Results from recent retrospective series demonstrate that stone-free rates and complication rates with ureteroscopy are comparable to percutaneous nephrolithotomy and shock wave lithotripsy. Although concerns remain with all endoscopic techniques in children regarding damage to the urinary tract and renal development, neither short-term nor long-term adverse effects have been consistently reported.

CONCLUSIONS

Shock wave lithotripsy, percutaneous nephrolithotomy and ureteroscopy are highly effective endourological techniques to treat stone disease in the pediatric population. A lack of prospective randomized trials comparing treatment modalities coupled with a vast disparity in the access to resources worldwide continues to individualize rather than standardize stone treatment in children.

Totally bloodless percutaneous renal surgery

INTRODUCTION

We evaluated the feasibility of intraoperative transarterial balloon occlusion of renal artery as a novel technique to reduce blood loss in high-risk patients undergoing complex percutaneous renal surgery (PRS).

METHODS

Four patients (staghorn calculi: n=2, renal pelvis TCC: n=1, ureteropelvic junction obstruction: n=1) underwent transfemoral arteriography prior to PRS. The renal artery was identified and an occluding balloon was inflated in the main renal artery. The kidney was intermittently allowed to perfuse with heparinized saline. Percutaneous renal access was obtained under fluoroscopic guidance by the urologist. Multiple tracts were established as needed to perform the procedure. The arterial occluding balloon was taken down at the completion of PRS and renal angiography repeated through the established angiographic catheter to identify any vascular injury.

RESULTS

Subjective improved visualization was attributed to decreased bleeding. Blood loss was less than 500 cc. Post-PRS intraoperative angiography revealed no active bleeding vessels requiring embolization. Two of the four patients presented with delayed renal hemorrhage over 10 days later requiring angiography and selective embolization with cessation of bleeding. All vascular abnormalities identified on repeat angiogram were not present on immediate post-PRS angiography.

CONCLUSIONS

Intraoperative balloon occlusion of renal artery is feasible and safe in patients undergoing complex PRS. Vascular control improves intraoperative endoscopic visibility while reducing intraoperative blood loss in patients at high risk for bleeding. However, these patients can still be at risk for delayed hemorrhage as iatrogenic vascular abnormalities, which can cause bleeding, can take time to develop and not be evident immediately post PRS.