Divertículos caliciales en niños: hallazgos radiológicos y formas de presentación / Calyceal diverticula in children: imaging findings and presentations

El divertículo calicial (DC) es una eventración quística intraparenquimatosa tapizada por epitelio celular transitorio con una estrecha conexión infundibular con los cálices o pelvis del sistema colector renal, por lo que el término más exacto es divertículo pielocalicial. Muy raro en la edad pediátrica, puede ser sintomático y requerir tratamiento. Está infradiagnosticado por confundirse con quistes renales simples por ecografía; su diagnóstico se confirma con tomografía computarizada (TC) o resonancia magnética (RM) en fase excretora, para determinar su seguimiento y manejo. Nuestro objetivo es mostrar las diferentes formas de presentación de los DC en la edad pediátrica, haciendo hincapié en los criterios ecográficos que permiten una aproximación diagnóstica y en los hallazgos definitivos en TC y RM. También discutimos el diagnóstico diferencial con otras lesiones quísticas renales y su tratamiento

A calyceal diverticulum consists of a cystic eventration in the renal parenchyma that is lined with transitional cell epithelium with a narrow infundibular connection with the calyces or pelvis of the renal collector system; thus, the term pyelocalyceal diverticulum would be more accurate. Very rare in pediatric patients, calyceal diverticula can be symptomatic and require treatment. Calyceal diverticula are underdiagnosed because they can be mistaken for simple renal cysts on ultrasonography. To determine the approach to their follow-up and management, the diagnosis must be confirmed by excretory-phase computed tomography (CT) or magnetic resonance imaging (MRI). This article aims to show the different ways that calyceal diverticula can present in pediatric patients; it emphasizes the ultrasonographic findings that enable the lesion to be suspected and the definitive findings that confirm the diagnosis on CT and MRI. It also discusses the differential diagnosis with other cystic kidney lesions and their treatment

Caliceal Fluid Temperature During High-Power Holmium Laser Lithotripsy in an In Vivo Porcine Model.

INTRODUCTION: With increasing use of high-power laser settings for lithotripsy, the potential exists to induce thermal tissue damage. In vitro studies have demonstrated that temperature elevation sufficient to cause thermal tissue damage can occur with certain laser and irrigation settings. The objective of this pilot study was to measure caliceal fluid temperature during high-power laser lithotripsy in an in vivo porcine model. METHODS: Four female pigs (30-35 kg) were placed under general anesthesia and positioned supine. Retrograde ureteroscopy with entry into upper or middle calices was performed. Thermocouples were placed into the calix by open exposure and puncture of the kidney or retrograde alongside the ureteroscope. A 242 µm laser fiber was positioned in the center of the calix and activated (0.5 J, 80 Hz, 40 W) for 60 seconds with high, medium, or no irrigation delivered in each trial. Finite element simulations of laser-induced heating in a renal calix were also performed. RESULTS: Peak temperatures of 84.8°C, 63.9°C, and 43.6°C were recorded for no, medium, and high irrigation, respectively. Mean time to reach threshold of thermal injury (t43 of 120 minutes) was 12.7 and 17.8 seconds for no and medium irrigation. Thermal damage thresholds were not reached in high-irrigation trials. Numerical simulations revealed similar results with peak spatial average fluid temperatures of >100°C, 58.5°C, and 37.5°C during 60 seconds of laser activation for 0.1, 15, and 40 mL/minute irrigation, respectively. CONCLUSIONS: High-power holmium laser settings (40 W) can induce potentially injurious temperatures in the porcine in vivo model, particularly with slower irrigation rates. Characterization of thermal dose across a broader range of laser parameter settings is underway to map out the thermal safety envelope.

The best calyceal tract approach for treating renal stones with percutaneous nephrolithotomy.

OBJECTIVE: To compare the perioperative outcomes of percutaneous nephrolithotomy (PCNL) performed via the upper middle, and lower calyces. MATERIAL AND METHOD: The authors retrospectively reviewed 92 renal units in 92 patients who required PCNL at our institution between 2006 and 2010. Patients with partial and full staghorn stones with total stone size > or = 2 cm were included in the present study. Patients were excluded if they had multiple small stones or a single stone < 2 cm. The present study analyzed 92 renal units in 92 patients. The authors divided the patients into three groups (groups 1, 2, and 3) based on the surgical approach, which was the upper middle, and lower calyceal approaches. PCNL was performed using a standard ultrasonic lithotriptor with a rigid nephroscope, and holmium: YAG laser lithotripsy was carried out with a flexible nephroscope, with simultaneous nitinol tipless basket extraction of fragments. Procedures were repeated until the patients were rendered stone-free (confirmed visually or by nephrostogram). Estimated blood loss, length of hospital stay, operative time, and the number of procedures (to achieve stone-free status) were analyzed and compared among the groups, and complications were reported. RESULTS: The present study showed that the length of hospital stay, estimated blood loss, number of procedures, and operative time were not significantly different between the three groups. In Group 1, four patients had complications and included two patients with mid-ureteral stone, and one patient each with renal pelvic perforation and urinary tract infection with sepsis. One patient from Group 2 contracted a urinary tract infection. In Group 3, five patients exhibited complications and included one with mid-ureteral stone, two with renal hemorrhage, and two with urinary tract infection. CONCLUSION: The estimated blood loss, duration of hospital stay, operative time, number of procedures (to achieve stone-free status), and complications did not statistically differ between the three groups. Moreover very few complications occurred in the different surgical approaches. Therefore, PCNL via all the three approaches were deemed safe and effective.

La ureterocalicostomía: ¿una cirugía olvidada? / Ureterocalicostomy: a forgotten surgical technique?

Introducción: la ureterocalicostomía es una técnica quirúrgica que tiene escasas indicaciones y que los urólogos utilizan muy raramente en la actualidad. Material y método: se presenta una paciente con un proceso cicatricial de retracción piélica derecha, que condicionaba uropatía obstructiva sobre los sistemas caliciales superior y medio, y que excluía el sistema calicial inferior. Se llevó a cabo exploración quirúrgica y se efectuó ureterocalicostomía con resultado exitoso. A muy largo plazo la paciente se encuentra curada y con normofuncionalismo renal. Resultados: se presentan los detalles técnicos de dicha cirugía y se revisan, desde una perspectiva actual, las indicaciones de esta técnica y los condicionantes necesarios para obtener un buen resultado. Conclusión: la ureterocalicostomía es una técnica casi olvidada por el urólogo actual, que mantiene vigentes aún algunas indicaciones y premisas. Por ello, debe conocerse y tenerse presente en el arsenal quirúrgico del urólogo dedicado a la cirugía reconstructiva (AU)

Introduction: ureterocalicostomy is a surgical technique that is rarely indicated and that urologists currently apply very occasionally. Materials and method: a patient with a right pyelical retraction cicatricial process, which resulted in obstructive uropathy of the upper and mid caliceal system, excluding the lower caliceal system is presented. We performed a surgical exploration and ureterocalicostomy with successful result. In the very long term, the patient is cured and has normal kidney functionalism. Results: we present the technical results of the surgery and, from a present-day perspective, we review the indications of this technique and the determining factors required to obtain good results. Conclusion: ureterocalicostomy is a technique that present-day urologists have almost forgotten, which still maintains some indications and premises effective. For this reason, urologists dedicated to reconstructive surgery must know this technique and include it in their surgical arsenal (AU)

Post transplant ureteric stenosis causing allograft hydronephrosis and calyceal rupture: salvage side to side ureteroneocystostomy.

A 26-year-old lady with end stage renal disease who received a cadaveric renal transplant, presented with ureteral stenosis as well as calyceal rupture due to hydronephrosis that was unresponsive to balloon dilation and the allograft was salvaged by a side to side ureteroneocystostomy. The symptoms and renal function improved and patency of the side to side uretroneocystostomy was confirmed post operatively and also at seventeen month follow-up. It may be reasonable to treat post-transplant ureteral stenosis resistant to balloon dilation with this technique. However, long-term follow-up is required to evaluate the efficacy of this treatment.

Evaluation of UPJ obstruction before and after pyeloplasty using MR urography.

This article builds on the previous article in this symposium and shows how MR urography contributes to the postoperative evaluation of children with UPJ obstruction. By analyzing the postoperative results, we derived new insights into their preoperative evaluation. With MR urography we combine simultaneous physiological and anatomic evaluation that enables us to identify changes in renal pathophysiology that occur in association with impaired drainage and obstruction. We studied 35 children before and after pyeloplasty. The pyeloplasty was considered successful in 30 and unsuccessful in 5. Both anatomic and functional criteria were used. The anatomic parameters included the degree of hydronephrosis, the appearance of the renal parenchyma, the quality of the nephrogram and the presence of crossing vessels. The functional criteria included the renal transit time, the calyceal transit time, the volumetric differential function, the Patlak differential function, the difference between the volumetric and Patlak differential function and the Patlak number per milliliter of renal tissue. No single parameter was sufficient to fully characterize UPJ obstruction, but by synthesizing all the information we were able to subdivide UPJ obstruction into compensated, decompensated and uropathic kidneys. Decompensated systems had the most significant improvement following successful pyeloplasty. Compensated systems showed little improvement in renal function, and uropathic kidneys were associated with a poor prognosis. It is clear that not all UPJ obstructions are the same, and it seems logical that treatment should be individually tailored rather than using a standard approach for all cases. Because MR urography can identify pathophysiological differences in children with UPJ obstruction that are occult to renal scintigraphy, it has an important potential role in identifying those who will benefit most from pyeloplasty and those who are probably best observed.

MR urography evaluation of obstructive uropathy.

Hydronephrosis and the evaluation of obstructive uropathy are the most common indications for MR urography in our practice. Typically our patients fall into one of two groups: infants with antenatal hydronephrosis and older children who present with abdominal pain, hematuria or urinary tract infection. Obstruction in children is usually chronic and partial. Intermittent episodes of increased pressure occur when the urine production exceeds the capacity for drainage. MR urography uses a fluid and diuretic challenge to assess the hydronephrotic kidney. High-quality anatomic images provide a morphologic assessment of the hydronephrotic system. Although it is relatively straightforward to determine if a system is not obstructed on the basis of the renal transit time (RTT), no single parameter is adequate to fully characterize obstruction. By evaluating the changes in signal intensity in the renal parenchyma following contrast administration, the hydronephrotic systems are classified as compensated or decompensated. Delayed RTT and the presence of urine-contrast levels indicate stasis. Calyceal transit time and the difference between the volumetric and the Patlak differential renal function (vDRF-pDRF) are measures of the physiologic changes within the kidney. Additionally, MR urography provides prognostic information by assessing the quality of the renal parenchyma and identifying uropathy preoperatively. MR urography combines both anatomic and functional information in a single test and is capable of providing a comprehensive evaluation of obstructive uropathy that could ultimately help select those patients most likely to benefit from surgical intervention.

Pre-percutaneous nephrolithotomy opacification for caliceal diverticular calculi.

Caliceal diverticula harbor calculi in as many as 50% of cases. Such stones rarely pass spontaneously. Various stone-removal techniques have been used, with percutaneous techniques generally having the best results. In patients with nonradiopaque stones or in whom the diverticulum does not opacify when contrast is instilled retrograde or by intravenous urogram, contrast can be instilled directly into the cavity with CT or ultrasound guidance. Three such cases are described, with good results.

Duplex systems.

Duplex kidneys occur in 0.8% of the general population, many of whom are asymptomatic. Children with duplex kidneys may be prone to urinary tract infections because of vesico-ureteric reflux or obstruction. Surgical management is usually required once symptoms occur. Increasing numbers of duplex kidneys are now prenatally diagnosed by ultrasound, resulting in the development of early postnatal strategies to try and reduce morbidity.

The nitric oxide pathway in pig isolated calyceal smooth muscle.

In pig and humans, whose kidneys have a multi-calyceal collecting system, the initiation of ureteral peristalsis takes place in the renal calyces. In the pig and human ureter, recent evidence suggests that nitric oxide (NO) is an inhibitory mediator that may be involved in the regulation of peristalsis. This study was designed to assess whether the NO synthase/NO/cyclic GMP pathway modulates the motility of pig isolated calyceal smooth muscle. Immunohistochemistry revealed a moderate overall innervation of the smooth muscle layer, and no neuronal or inducible NO synthase (NOS) immunoreactivities. Endothelial NOS immunoreactivities were observed in the urothelium and vascular endothelium, and numerous cyclic GMP-immunoreactive (-IR) calyceal smooth muscle cells were found. As measured by monitoring the conversion of L-arginine to L-citrulline, Ca(2+)-dependent NOS activity was moderate. Assessment of functional effects was performed in tissue baths and showed that NO and SIN-1 decreased spontaneous and induced contractions of isolated preparations in a concentration-dependent manner. In strips exposed to NO, there was a 10-fold increase of the cyclic GMP levels compared with control preparations (P < 0.01). It is concluded that a non-neuronal NOS/NO/cyclic GMP pathway is present in pig calyces, where it may influence motility. The demonstration of cyclic GMP-IR smooth muscle cells suggests that NO acts directly on these cells. This NOS/NO/cyclic GMP pathway may be a target for drugs inhibiting peristalsis of mammalian upper urinary tract. Neurourol. Urodynam. 18:673-685, 1999.

Unicalyceal kidney associated with ureteral anomalies.

A unicalyceal kidney is a very rare anomaly of the urinary system. We report 4 cases of unicalyceal kidneys in infants. All cases were associated with ureteral anomalies: megaureter on the involved side, and/or ectopic ureter with vesicoureteral reflux or renal agenesis on the contralateral side. In order to preserve renal function we recommend surgical treatment for patients with unicalyceal kidney when they have ureteral anomalies.

[Megapolycalicosis. A case report]. / Megapolicalicosi. Descrizione di un caso.

Megapolycalicosis is defined as a congenital dilatation of calices without evidence of obstruction. In absence of complications such as infection and stones, megapolycalicosis would not have a particular clinical relevance if not for the possible misinterpretation as hydronephrosis. A case of megapolycalicosis is presented.

Effect of furosemide and intravenous normal saline fluid load upon the renal resistive index in nonobstructed kidneys in children.

Recent literature has shown that relative to baseline the renal resistive index remains unchanged in nonobstructed kidneys and increases in obstructed kidneys after administration of furosemide. To our knowledge the effect upon the renal resistive index of furosemide administered in conjunction with intravenous normal saline fluid load has not been reported. We evaluated the renal resistive index in 13 nonobstructed kidneys in 8 children 6 to 18 years old before and after furosemide and intravenous normal saline fluid load. The mean resistive index decreased from baseline (mean decrease was 0.06 +/- 0.06 standard deviation), with the observation of a resistive index decrease significant to p < 0.005). It appears likely that the combination of an intravenous normal saline fluid load and furosemide caused the resistive index decrease, since a decrease was not observed with furosemide alone; however, these results cannot exclude the possibility that the resistive index decrease was due to the intravenous normal saline fluid load alone. Nonetheless, these data are important since they may provide the foundation for the development of a pharmacologically challenged Doppler sonographic examination using furosemide and intravenous normal saline fluid load to evaluate better potentially obstructed kidneys.

Does the Whitaker test add to antegrade pyelography in the investigation of collecting system dilatation in renal allografts?

Significant pelvicalyceal dilatation in renal allografts is currently investigated by antegrade pyelography. However, the clinical significance of a radiologically demonstrated narrowing of the ureter is unclear. Over a 21-month period 26 of 155 renal allografts with pelvicalyceal dilatation were investigated by antegrade pyelography. In eight allografts no ureteric stenosis could be identified. Two grafts were shown to have ureteric necrosis and required surgical intervention and 16 of the other grafts appeared to have a ureteric stenosis. 15 of the 16 allografts with radiological ureteric stenosis underwent a concurrent pressure flow study to assess the functional relevance of the ureteric narrowing. As shown by a pressure rise of > 7 mmHg at a perfusion rate of 10 ml min-1, 11 of the 15 grafts were functionally obstructed and were treated by a nephrostomy catheter followed by antegrade insertion of a ureteric stent. The four grafts with a negative pressure flow study were subsequently shown on biopsy to have rejection. The diagnosis of allograft rejection was also confirmed by biopsy in seven of the eight allografts without a radiological ureteric stenosis. The last of the eight allografts was found to be cyclosporin toxic. Pelvicalyceal dilatation of renal allografts is appropriately investigated by antegrade pyelography in combination with a pressure flow study which identifies those grafts with mechanical obstruction.

[Tumor of the urinary tract and renal lithiasis. Apropos of 4 cases]. / Tumeur de la voie excrétrice et lithiase rénale. A propos de 4 cas.

The authors present four observation of renal lithiasis associated with a tumor of the upper urinary tract. The rarity of this association and the facility to only consider lithiasis often conceal the tumor. They define the "high risk lithiasis" for which CT-scan is mandatory. Tumor of the urinary tract has to be treated and the prognosis becomes less favorable.

The impact of total unilateral ureteral obstruction on intrarenal angiotensin II production in the polycalyceal pig kidney.

Nine pigs with unilateral complete ureteral obstruction were investigated for 15 hours. Obstruction of the ureter resulted in a maximum intrapelvic pressure of 60 cmH2O within the first hour after obstruction, and a gradual decline to 40 cmH2O during the next 15 hours. In 6 pigs both renal veins were catheterized together with the abdominal aorta allowing measurement of the hormonal difference over the kidney. Plasma angiotensin II, plasma vasopressin and plasma atrial natriuretic peptide concentrations were determined. Arterial concentration of plasma angiotensin II gradually increased from 38.7 pg/ml to 252.3 pg/ml. The highest concentrations of angiotensin II were found from the ipsilateral renal vein. From 1 hour after obstruction and onward there was a negative extraction ratio of angiotensin II from the ipsilateral kidney indicating enhanced intrarenal generation of angiotensin II. No difference in vasopressin was found among the sample sites, but a significant reduction in vasopressin from 15.2 pg/ml to 4.9 pg/ml was found from the ipsilateral renal vein during the 15 hours of unilateral ureteral obstruction. Arterial atrial natriuretic peptide concentrations were higher than renal venous levels at all times. Glomerular filtration was immediately reduced to 58%. It is suggested that an increased ipsilateral generation of intrarenal angiotensin II is at least partly responsible for some of the changes in kidney function during acute obstruction.

[Fornix rupture--a review of pathophysiology and clinical aspects]. / Fornix-Ruptur--Uberprüfung der Pathophysiologie und der Klinik.

Rupture of the fornix renalis, a special form of obstructive nephropathy that receives too little attention as a separate entity, is reintegrated into urological thinking, with a fuller description of the pathophysiology, morphology and clinical course than has previously been given. Overloading (iatrogenic mainly) of the lymphatic and venous system of the kidney caused by excessive pressure is usually implicated, affecting the renal parenchyma, the renal sinus and Gerota's fascia. Rupture of the calyceal fornix renalis functions partly as a self-help mechanism. Measurement of the urovascular diversions of urine caused by obstruction is not yet possible. Clinical observation and experimental reproduction give predominantly corresponding results. Schematics make the text easier to understand. Recent ureteroscopic techniques are introduced to bring the topic up to date.

Lower pole divergence of kidney: a new surgical technique to prevent recurrent renal calculus.

Gravity and natural position of the kidney have emerged as important factors in the nucleation, growth and postoperative recurrences of renal stones. A new operation technique is described to alter the position of the kidney, hence countering all obstacles to urinary flow. Recurrence of stones after the new operation (8.1%) were compared with controls (15.0%). Recurrence rates revealed from history data at two years (15-28%) and life-time recurrences deduced therefrom (25-80% or more) were used for comparison. Postnephropexy figures were 5.97% and 10-25% respectively. It strengthened our belief that to check inevitable postoperative recurrences, this new operation should be applied whenever open surgery is performed for nephrolithiasis.

[Pacemakers of the upper urinary tract using power spectral analysis of spontaneous activity]. / Untersuchung der Schrittmacher der oberen Harnwege mit Hilfe von Leistungsdichte-Spektren der Spontanaktivität.

Spontaneous activity of isolated smooth muscle strips of the upper urinary tract has been analysed by time series analysis. Frequency components of spontaneous contractions of the human urinary tract have been determined quantitatively by means of power spectral analysis. This method allows to characterise exact frequency components of rhythmicity in various parts of the urinary tract and accordingly helps to localise the site of various pacemakers. The results indicate tentatively the existence of two different pacemakers located in the wall of calix and pelvis. Furthermore, it is assumed that these pacemakers complement each other both cooperatively and by additive functioning, as though in shifts (reverberation), to stimulate urine transport through the pyeloureter.