Constant elevation in renal pelvic pressure induces an increase in urinary N-acetyl-beta-D-glucosaminidase in a nonobstructive porcine model

Elevated hydrostatic pressure disturbs expression of growth factors in human renal epithelial cells

Obstructive uropathy is a common kidney disease caused by elevated hydrostatic pressure (HP), but relevant molecular and cellular mechanisms have not yet been well understood. In this study, we ex vivo investigated the effects of elevated HP on human renal epithelial cells (HREpCs). Primary HREpCs were subjected to 100 cmH2O HP for 8 or 48 h. Then, the cells were cultured without HP stimulation for another 24 h or 72 h. Cell morphology showed almost no change after 8h HP treatment, but exhibited reversible elongation after 48h HP treatment. HP treatment for 8 h increased the expression of TGFB1 and VEGFA but decreased the expression of CSF2 and TGFB2. On the other hand, HP treatment for 48 h downregulated the expression of CSF2, TGFB2, PDGFB, VEGFA, and VEGFB, while upregulated the expression of TGFB3. Interestingly, all changes induced by 48 h HP treatment were detected more severe compared to 8 h HP treatment. In conclusion, elongated ex vivo HP loading to renal epithelial cells induces reversible changes on cell morphology and disturbs the expression of several growth factors, which provides novel mechanistic insight on elevated HP-caused kidney injury such as obstructive uropathy.

Intrarenal pressure detection during flexible ureteroscopy with fiber optic pressure sensor system in porcine model

To validate the feasibility of a fiber-optic pressure sensor-based pressure measurement device for monitoring intrarenal pressure and to analyze the effects of ureteral acess sheath (UAS) type, surgical location, perfusion flow rate, and measurement location on intrarenal pressure (IRP). The measurement deviations and response times to transient pressure changes were compared between a fiber-optic pressure sensing device and a urodynamic device IRP in an in vitro porcine kidney and in a water tank. Finally, pressure measurements were performed in anesthetized female pigs using fiber-optic pressure sensing device with different UAS, different perfusion flow rates, and different surgical positions at different renal calyces and ureteropelvic junctions (UPJ). According to our operation, the result is fiber optic pressure sensing devices are highly accurate and sensitive. Under the same conditions, IRP varied among different renal calyces and UPJ (P < 0.05). IRP was lowest at 50 ml/min and highest at 150 ml/min (P < 0.05). Surgical position had a significant effect on IRP (P < 0.05). 12/14 Fr UAS had a lower IRP than 11/13 Fr UAS. Therefore fiber optic pressure sensing devices are more advantageous for IRP measurements. In ureteroscopy, the type of ureteral sheath, the surgical position, the perfusion flow rate, and the location of the measurement all affect the intrarenal pressure value.

Evaluation of the effect of 9.5/11.5-fr ureteral access sheath use on acute kidney injury with the myo-inositol oxygenase biomarker in patients undergoing retrograde intrarenal surgery: a prospective, randomized, and controlled study

INTRODUCTION

We aimed to investigate whether a low intrarenal pressure provided by ureteral access sheath (UAS) use had a positive effect on the prevention of acute kidney injury through the evaluation of the myo-inositol oxygenase (MIOX).

MATERIAL AND METHODS

The patients were divided into two groups according to whether a 9.5/11.5-Fr UAS was used during retrograde intrarenal surgery (RIRS): UAS group and non-UAS group. RIRS was performed under gravity irrigation and manual pumping was not used. For the measurement of MIOX, 5 cc blood samples were taken from the patients preoperatively and four hours postoperatively.

RESULTS

Operation time and hospital stay were significantly longer in the UAS group. The mean preoperative and postoperative MIOX values were 0.77 ± 0.36 ng/ml and 0.74 ± 0.38 ng/ml, respectively, in the UAS group, and 0.74 ± 0.31 ng/ml and 0.83 ± 0.40 ng/ml, respectively, in the non-UAS group. The mean MIOX change was -0.29 ± 0.36 in the UAS group and 0.08 ± 0.44 in the non-UAS group, indicating no significant difference between the groups.

CONCLUSION

Even if UAS is not used, significant acute kidney injury is not observed under gravity irrigation and therefore, if we avoid manual pumping, the intrarenal pressure remains low, thus potentially rendering the use of 9,5/11,5-Fr UAS unnecessary.

Intrarenal Pressure Measured Using a Novel Flexible Ureteroscope with Pressure Sensing Capabilities: A Study of the Effects of Ureteral Access Sheath, Irrigation, and Working Channel Accessories

Introduction: Intrarenal pressure is emerging as an important monitoring parameter during flexible ureteroscopy (fURS). We measure how intraoperative conditions affect intrarenal pressure using a novel pressure sensing ureteroscope. Methods: The LithoVue Elite (LVE) single-use digital flexible ureteroscope (Boston Scientific) is the first commercial ureteroscope that senses pressure at its tip. LVE was used in a porcine model to measure intrarenal pressure with and without a ureteral access sheath (UAS) with various sizes and placement locations, irrigation methods, and working channel accessories. LVE pressure accuracy was measured in a bench model. This abstract shows the least-square means from multiway analysis of variances used for analysis. Results: Intrarenal pressures were the highest without a UAS (64 mm Hg), followed by the 11/13 UAS (51 mm Hg) and the 12/14 and 13/15, which were not statistically different (39-40 mm Hg). The pressures were highest with UASs placed at the ureteropelvic junction (61 mm Hg), and lowest if placed in the renal pelvis (24 mm Hg). Irrigation methods showed the highest pressures with syringe (57 mm Hg), while irrigation bags (pressurized at 150-300 mm Hg) produced 43 to 46 mm Hg and 25 mm Hg when applied with 80 cm of gravity. Placing a 200 μm laser fiber reduced pressures from 44 to 41 mm Hg. Finally, the bench model showed that LVE was 96% accurate up to 300 mm Hg. Conclusion: Intrarenal pressure significantly varied based on UAS sizes, placement, and irrigation methods. Accordingly, fURS with LVE is poised to be an invaluable tool for clinical decision-making and future studies of intrarenal pressure.

The effect of irrigation rate on intrarenal pressure in an ex vivo porcine kidney model-preliminary study with different flexible ureteroscopes and ureteral access sheaths

INTRODUCTION

Ureteral access sheath (UAS) and irrigation are used in flexible ureteroscopy (fURS). Both conventional UAS (cUAS) and vacuum-assisted UAS (vaUAS) are currently available. Irrigation increases the intrarenal pressure (IRP). Our objectives were to study the effects of various irrigation rates on IRP using different sizes of fURS in different sizes and functions of UAS.

MATERIALS AND METHODS

Ten freshly harvested porcine kidneys served as the study subjects. 11/13F and 12/14F cUAS and vaUAS with 2.8 mm and 3.2 mm fURS were experimented on in various scope/sheath combinations. 6F pressure monitor catheters were placed into upper, middle, and lower calyces. IRPs were recorded under different irrigation rates in cUAS and vaUAS, with either 150 or 300 mmHg aspiration pressures, and with air vent either open or closed.

RESULTS

12/14F cUAS with 2.8 mm fURS could maintain IRPs below 35 mmHg with irrigation rates up to 200 cc/min. With 3.2 mm fURS, the rate dropped to 110-120 cc/min. With 12/14F vaUAS and vent closed, the IRP remained less than 5 mmHg at 200 cc/min irrigation for both fURS. For 11/13F cUAS, the < 35 mmHg threshold for 2.8 mm fURS was 80-90 cc/min; for 3.2 mm fURS, it was 30-40 cc/min. For 11/13F vaUAS with vent closed, IRPs remained < 5 mmHg at 200 cc/min irrigation for both scopes.

CONCLUSION

Both 12F cUAS and vaUAS can be used safely with 2.8 mm fURS up to 200 cc/min irrigation. With either a smaller sheath or a larger scope, vaUAS with vent closed can maintain IRP in a safe range up 200 cc/min irrigation. vaUAS with vent open performed marginally better than cUAS.

Comparison of intrarenal pressure between convention and vacuum-assisted ureteral access sheath using an ex vivo porcine kidney model

OBJECTIVE

This study aimed to prove the vacuum-assisted ureteral access sheath (vaUAS) is more effective in maintaining a lower IRP than conventional ureteral access sheath (cUAS).

MATERIALS

The model consisted of 12 freshly harvested adult porcine kidneys.

METHODS

Either a 12/14F cUAS or vaUAS was alternately inserted into the ureter to one cm below the renal pelvis. Upper, middle, and lower calyces were punctured, and 6F pressure monitor catheters were introduced. IRP with cUAS was monitored using various irrigation rates. IRP with vaUAS was monitored with the same irrigation rates; various aspiration pressures; and vent fully closed, 50% closed, and fully open.

RESULTS

cUAS with irrigation rate of 50 cc/min resulted in IRP < 30 mmHg. 50 to 100 cc/min should be used with caution. When irrigation rate exceeded 100 cc/min, IRP rose to ≥ 30 mmHg in most instances. With vent closed, vaUAS with vacuum pressure ≥ 150 mmHg and irrigation rate of 50 cc, 100 cc, and 150 cc/min generally resulted in IRPs < 5 mmHg. With vent half closed, vaUAS with vacuum pressure ≥ 300 mmHg and irrigation rate of ≤ 100 cc/min avoided IRP > 30 mmHg. vaUAS with vent open showed limited advantages over cUAS.

CONCLUSION

vaUAS maintains lower IRP than cUAS under same parameters. Both vaUAS and cUAS can be used when irrigation is ≤ 50 cc/min vaUAS showed clear advantages over cUAS in maintaining lower pressure when irrigation rate is ≥ 100 cc/min.

Comparison of intrarenal pressure between convention and vacuum-assisted ureteral access sheath using an ex vivo porcine kidney model

OBJECTIVE

This study aimed to prove the vacuum-assisted ureteral access sheath (vaUAS) is more effective in maintaining a lower IRP than conventional ureteral access sheath (cUAS).

MATERIALS

The model consisted of 12 freshly harvested adult porcine kidneys.

METHODS

Either a 12/14F cUAS or vaUAS was alternately inserted into the ureter to one cm below the renal pelvis. Upper, middle, and lower calyces were punctured, and 6F pressure monitor catheters were introduced. IRP with cUAS was monitored using various irrigation rates. IRP with vaUAS was monitored with the same irrigation rates; various aspiration pressures; and vent fully closed, 50% closed, and fully open.

RESULTS

cUAS with irrigation rate of 50 cc/min resulted in IRP < 30 mmHg. 50 to 100 cc/min should be used with caution. When irrigation rate exceeded 100 cc/min, IRP rose to ≥ 30 mmHg in most instances. With vent closed, vaUAS with vacuum pressure ≥ 150 mmHg and irrigation rate of 50 cc, 100 cc, and 150 cc/min generally resulted in IRPs < 5 mmHg. With vent half closed, vaUAS with vacuum pressure ≥ 300 mmHg and irrigation rate of ≤ 100 cc/min avoided IRP > 30 mmHg. vaUAS with vent open showed limited advantages over cUAS.

CONCLUSION

vaUAS maintains lower IRP than cUAS under same parameters. Both vaUAS and cUAS can be used when irrigation is ≤ 50 cc/min vaUAS showed clear advantages over cUAS in maintaining lower pressure when irrigation rate is ≥ 100 cc/min.

Counter-Irrigation as a Novel Technique versus the Standard Technique in Percutaneous Nephrolithotomy: A Prospective Randomized Trial

OBJECTIVE

This study aimed to evaluate the efficacy of our counter-irrigation technique versus the standard technique in percutaneous nephrolithotomy (PCNL) by assessment of the stone-free rate after the procedures and its safety in terms of comparing the intraoperative time, Hb deficit, blood transfusion, length of hospital stay, auxiliary procedures, and perioperative complications with that of the standard one.

METHODS

This prospective randomized trial was conducted on patients with renal stone 2-3 cm in diameter without contraindications to PCNL. The patients were randomized into group A in which the counter-irrigation technique has been performed and group B who were managed by the standard technique. The preoperative characteristics including demographic data and stone parameters were compared between both groups. The primary outcome was the stone-free rate assessed by noncontrast spiral CT after 3 months. The secondary outcome included intraoperative time, Hb deficit, blood transfusion, hospital stay, auxiliary procedure required, and rate of complications.

RESULTS

Forty-eight patients were included in this study. Overall, no significant difference was observed between both groups regarding preoperative characteristics, Hb deficit, and complication rate. Operative time was significantly shorter in group B (p = 0.001). None of our patients required blood transfusion. The stone-free rates at 3 months were significantly better in group A (95% for group A and 70% for group B, p = 0.04).

CONCLUSIONS

Our results indicate that our counter-irrigation technique has lower stone migration with subsequent significantly better stone-free rate versus the standard technique. We can recommend this technique as a potentially valid option for cases with large stone burden when the access to the upper calyx is feasible to minimize significant residual fragments.

Can Urinary KIM-1 and NGAL Predict Management Endoscopic Surgery in Acute Unilateral Obstructive Stone Disease? Results from a Prospective Cohort Study

INTRODUCTION

Kidney injury molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) are the leading novel biomarkers used efficiently in acute kidney injury (AKI). The levels of these biomarkers increase especially in the early period of nephrotoxic and ischemic renal damage. In this study, we aimed to investigate the clinical importance of NGAL and KIM-1 biomarkers used in the effective evaluation of kidney functions in patients with acute unilateral obstructive stone disease (AUOSD) in the management of endoscopic surgery.

MATERIALS AND METHODS

We prospectively included patients who underwent endoscopic surgery due to AUOSD between January 2018 and December 2019. Urine KIM-1 and NGAL values of the patients were measured preoperative period, postoperative 4th h, and postoperative 7th day. The patients were evaluated according to the location and size of the stone, the degree of renal hydronephrosis, the duration of the operation, complications, and JJ stent placement.

RESULTS

The study enrolled 50 patients. Urinary KIM-1/Cr and urinary NGAL/Cr ratios were higher in postoperative 4th h than in others (p < 0.001). Also, we found that urinary KIM-1/Cr and urinary NGAL/Cr ratios with Grade 2 and higher hydronephrosis were statistically higher than Grade 0-1 hydronephrosis (p < 0.001 and p: 0.042, respectively). Additionally, a preoperative urinary KIM-1 value of 1.24 ng/mL had a sensitivity of 78% and a specificity of 63% to predict the presence of hydronephrosis. When urine KIM-1 and NGAL results were compared with surgery time, stone size and location, serum creatinine (sCr) value, and Post-Ureteroscopic Lesion Scale grade, the difference was not statistically significant. Postoperative 7th day NGAL/Cr and KIM-1/Cr ratios were statistically higher in those with JJ stents placed (p: 0.03 and p: 0.004, respectively).

CONCLUSION

KIM-1 and NGAL can be used in our assessment of renal function in patients with AUOSD, even if sCr is normal. Also, these biomarkers can predict the presence of hydronephrosis. It can be helpful in determining the time of surgical treatment, as well as providing information in the follow-up of patients with JJ stents after treatment.

Controversies associated with ureteral access sheath placement during ureteroscopy

The use of ureteral access sheaths (UAS) is common practice during routine flexible ureteroscopy procedures. However, debates and concerns continue amongst endourologists on routine UAS placement. UAS placement allows for multiple passages of the ureteroscope, decreases intrarenal pressure, and may improve stone-free rates. However, concerns for the UAS's effectiveness in these claimed benefits and complications related to UAS placement has been documented and investigated by many. In this review, we will discuss the controversies surrounding the placement of UAS during ureteroscopy.

Evaluation of the Impact of Ureteroscope, Access Sheath, and Irrigation System Selection on Intrarenal Pressures in a Porcine Kidney Model

Introduction: Elevated intrarenal pressure (IRP) during flexible ureterorenoscopy (FURS) is a predictor of postoperative complications. The aim of this study is to evaluate IRP during FURS in a porcine kidney model to determine the safest combination of irrigation device, ureteral access sheath (UAS), and ureteroscope. Methods: Urinary tracts were harvested from Landrace pigs slaughtered for the food chain. Two flexible ureteroscopes, 8.7F and 9.5F, were evaluated. Irrigation systems evaluated included the following: TraxerFlow™ (Rocamed, France), SAPS™ single action pumping system (Boston Scientific), Pathfinder Plus™ (Utah Medical), and a manual "bag squeeze." This experiment was conducted with no UAS, followed by an 11/13F UAS and then a 12/14F UAS. IRPs were measured in the prepared porcine kidney during all possible combinations of scope, UAS, and irrigation system. Results: Pressures were significantly reduced when using 12/14F UAS compared with 11/13F UAS (16.45 ± 5.3 cmH₂O vs 32.73 ± 35.66 cmH₂O, p = 0.006), and when using 11/13F UAS compared with no UAS (32.73 ± 35.66 cmH₂O vs 49.5 ± 29.36 cmH₂O, p = 0.02). Pressures were significantly reduced with the 8.7F scope compared with the 9.5F scope (24.1 ± 21.24 cmH₂O vs 41.68 ± 34.5 cmH₂O, p = 0.001). SAPS generates significantly greater IRP than TraxerFlow, Pathfinder Plus, and a "bag squeeze" (p < 0.05). The most dangerous combination was using the SAPS, no UAS, and larger ureteroscope leading to an IRP of 100.6 ± 16.1 cmH₂O. The safest combination was using Pathfinder Plus with a 12/14F UAS and smaller ureteroscope giving an IRP of 11.6 ± 3.65 cmH₂O. Conclusion: IRPs are reduced by selecting larger UAS and a small ureteroscope. The SAPS generates significantly higher IRPs than other irrigation systems. To maintain safe IRPs during FURS, urologists should use large UAS, narrow ureteroscopes, and be cautious in the selection of an irrigation device.

Correlation of Operative Time with Outcomes of Ureteroscopy and Stone Treatment: a Systematic Review of Literature

PURPOSE OF REVIEW

To present the latest evidence related to the impact of increased operative times in retrograde intrarenal surgery and identify possible important factors that can facilitate ureteroscopy procedures.

RECENT FINDINGS

Ureteroscopy constitutes the mainstay treatment of renal stones and is characterized by a huge variation in techniques and instrumentation. It has been suggested that increased operative times can mitigate the outcomes of the procedures by increasing complication rates. Nevertheless, little is known about the time limits, above which complications are likely to occur. Furthermore, complication rates in different procedure durations have not yet been assessed. Prolonged operative times are linked to increased complication rates in ureteroscopy. Stone complexity, patient risk factors, surgeon experience, bilateral surgery, and instrumentation constitute important factors that can hamper or facilitate a procedure and should be taken into account beforehand. Keeping procedural times below 90 min can dissuade potential predicaments and achieve improved stone-free rates.

Pressure matters: intrarenal pressures during normal and pathological conditions, and impact of increased values to renal physiology

PURPOSE

To perform a review on the latest evidence related to normal and pathological intrarenal pressures (IRPs), complications of incremented values, and IRP ranges during endourology.

METHODS

A literature search was performed using PubMed, restricted to original English-written articles, including animal, artificial model, and human studies. Different keywords were: percutaneous nephrolithotomy, PCNL, ureteroscopy, URS, RIRS, irrigation flow, irrigation pressure, intrarenal pressure, intrapelvic pressure and renal pelvic pressure.

RESULTS

Normal IRPs range from zero to a few cm H₂O. Pyelovenous backflow may occur at pressure range of 13.6-27.2 cm H₂O. During upper tract endourology, complications such as pyelorenal backflow, sepsis, and renal damage are directly related to increased IRPs. Duration of increased IRPs and concomitant obstruction are independent predictors of complication development.

CONCLUSIONS

IRP increase remains a neglected predictor of upper tract endourology complications and its intraoperative monitoring should be taken into consideration. Further research is necessary, to quantify pressures generated during upper tract endourology, and introduce means of controlling them.

Renal Pelvic Pressure in Percutaneous Nephrolithotomy: The Effect of Multiple Tracts

INTRODUCTION

During percutaneous nephrolithotomy (PCNL), elevated renal pelvic pressures (RPPs) may spread infection through pyelovenous backflow whereas decreased pressures can hinder observation and increase bleeding. The purpose of this study was to evaluate the effects of multiple access tracts and different sized endoscopic equipment on RPP in a porcine model.

MATERIALS AND METHODS

RPP was measured in one- vs two-tract access, rigid vs flexible nephroscopy, and suction vs no suction. Twenty trials were performed for each condition. An independent samples Mann-Whitney U-test was used to compare parameters, with p < 0.05 considered significant.

RESULTS

With one tract, rigid nephroscopy resulted in higher mean pressures (31.35 mm Hg) than flexible nephroscopy (11.1 mm Hg; p < 0.001). The RPP was higher with rigid nephroscopy in one tract (31.35 mm Hg) than when two tracts were present (9.35 mm Hg; p < 0.001). In contrast, there was no difference in pressure during the use of a flexible nephroscope in one (11.1 mm Hg) vs two tracts (10.7 mm Hg; p = 0.63). Use of suction with the rigid nephroscope resulted in significantly lower pressures with one (-1.3 mm Hg) than with two tracts (1.8 mm Hg; p = 0.004).

CONCLUSION

In PCNL, RPP is significantly affected by an additional tract during rigid nephroscopy and suctioning but not when using a flexible nephroscope. Understanding the effects of multiple tracts and equipment type on RPP may improve the safety of PCNL.

Investigating the flow dynamics in the obstructed and stented ureter by means of a biomimetic artificial model

Double-J stenting is the most common clinical method employed to restore the upper urinary tract drainage, in the presence of a ureteric obstruction. After implant, stents provide an immediate pain relief by decreasing the pressure in the renal pelvis (P). However, their long-term usage can cause infections and encrustations, due to bacterial colonization and crystal deposition on the stent surface, respectively. The performance of double-J stents - and in general of all ureteric stents - is thought to depend significantly on urine flow field within the stented ureter. However very little fundamental research about the role played by fluid dynamic parameters on stent functionality has been conducted so far. These parameters are often difficult to assess in-vivo, requiring the implementation of laborious and expensive experimental protocols. The aim of the present work was therefore to develop an artificial model of the ureter (i.e. ureter model, UM) to mimic the fluid dynamic environment in a stented ureter. The UM was designed to reflect the geometry of pig ureters, and to investigate the values of fluid dynamic viscosity (μ), volumetric flow rate (Q) and severity of ureteric obstruction (OB%) which may cause critical pressures in the renal pelvis. The distributed obstruction derived by the sole stent insertion was also quantified. In addition, flow visualisation experiments and computational simulations were performed in order to further characterise the flow field in the UM. Unique characteristics of the flow dynamics in the obstructed and stented ureter have been revealed with using the developed UM.

An artificial model for studying fluid dynamics in the obstructed and stented ureter

Fluid dynamics in the obstructed and stented ureter represents a non-trivial subject of investigation since, after stent placement, the urine can flow either through the stent lumen or in the extra-luminal space located between the stent wall and the ureteric inner wall. Fluid dynamic investigations can help understanding the phenomena behind stent failure (e.g. stent occlusions due to bacterial colonization and encrustations), which may cause kidney damage due to the associated high pressures generated in the renal pelvis. In this work a microfluidic-based transparent device (ureter model, UM) has been developed to simulate the fluid dynamic environment in a stented ureter. UM geometry has been designed from measurements on pig ureters. Pressure in the renal pelvis compartment has been measured against three variables: fluid viscosity (μ), volumetric flow rate (Q) and level of obstruction (OB%). The measurements allowed a quantification of the critical combination of μ, Q and OB% values which may lead to critical pressure levels in the kidney. Moreover, an example showing the possibility of applying particle image velocimetry (PIV) technology to the developed microfluidic device is provided.

MICROFILAMENTS ARE INVOLVED IN RENAL CELL RESPONSES TO SUSTAINED HYDROSTATIC PRESSURE

PURPOSE

Increased pressures within renal interstitial fluid, as associated with a number of renal pathologies, could affect cell function and gene expression. The long-term objective of this research is to elucidate kidney cell responses to pathological hydrostatic pressures.

MATERIALS AND METHODS

In vitro studies were performed in 2 kidney cell lines (cortical tubular and medullary) to determine changes in cell numbers and cytoskeletal (specifically microfilament, microtubule and intermediate filament) arrangement following exposure to pathological (60 cm H2O) pressures. A novel pressure system was used to apply pressure to renal cells for up to 7 days. Cell counts and fluorescent staining were performed to determine alterations in response to pressure.

RESULTS

Exposure to pressures of 60 cm H2O resulted in increased renal cell numbers and rearrangement in individual microfilament structures after 7 days.

CONCLUSIONS

These results prove that hydrostatic pressure alters the function of renal cells. In the future such knowledge of renal cell responses to pressure along with an understanding of the mechanisms involved will aid in the design of novel, targeted drug therapies for treating kidney pathologies.

Antenatally detected, unilateral dilatation of the renal pelvis: a critical review. 2. postnatal non-operative treatment--long-term hazards, urgent research

BACKGROUND

Even after two decades, there is still much discussion about the postnatal treatment of antenatally detected, isolated pelvic dilatation (consistent with pyelo-ureteral junction obstruction). A recent review concluded that non-operative expectancy seemed safe - even after 17 years in certain cases. However, the final outcome, i.e. when these children have reached old age, is remote.

OBJECTIVE

This review takes stock of conceivable long-term hazards and evaluates prognosticating tools, and offers a basis for protocols for future randomized controlled trials. Long-term hazards: Symptoms in this context are generally considered ominous. In the antenatally detected cases, i.e. primarily asymptomatic, symptoms have been reported but they were not necessarily combined with renal damage. Hydronephroses, so mild, that they are written off, may deteriorate later on (indeed insidiously), although probably seldom. Urgent research: A predictor of outcome is eagerly pursued but hard to obtain, due to the difficulty in defining true obstruction in compliant systems such as the urinary one. Ordinary diagnostics offer no help, but there are promising innovations: constant pressure/flow assessment (flow necessary to keep a preset intrapelvic pressure), NAG/creatinine in pelvic urine, and TGFbeta-1 in voided urine. Renal microstructure, sometimes severely damaged early (which disagrees with the good results with expectancies) could possibly herald future deterioration.

CONCLUSION

Adverse developments should be meticulously documented and published swiftly, so policy can be changed if necessary, before it is too late. Cognizance of their existence, not necessarily frequency and statistics, is then first order. Efforts to design prognosticating tools has also high priority.