Micro-ureteroscopy for the treatment of distal ureteral calculi in children

Microureteroscopy in the treatment of upper urinary tract stones in pediatric patients younger than 3 years of age

The aim of this study is to evaluate the usefulness of microureteroscopy (m-URS) in the treatment of renal and ureteral stones in children younger than 3 years of age. A retrospective analysis of pediatric patients aged < 3 years with upper urinary tract calculi who underwent lithotripsy was performed. The children were divided into the m-URS group (4.85 F, n = 41) and the ureteroscopy (URS) group (4.5/6.5 F, n = 42) according to the type of ureteroscope used. The mean age of the patients was 23.5 ± 10.7 months in the m-URS group and 20.6 ± 7.1 months in the URS group (P = 0.212). The success rate of one-stage surgery was 80.5% (33/41) for m-URS and 38.1% (16/42) for URS (P < 0.001). The success rates of m-URS were 60.0%, 69.2%, and 91.3% for stones located in the renal pelvis/calix, upper ureter, and mid-lower ureter, respectively. Eight children in the m-URS group and 26 children in the URS group underwent the second-stage ureteroscopic surgery. The mean operation time was 50 (30-60) min in the m-URS group and 40 (34-60) min in the URS group (P = 0.287). The complication rates were 4.9% and 7.1% in the m-URS and URS groups, respectively (P = 1.000). The stone-free rate at 1 month after lithotripsy was 87.8% in the m-URS group and 83.3% in the URS group (P = 0.563). The mean anesthesia session was 2.1 in the m-URS group and 2.5 in the URS group (P = 0.002). M-URS can effectively reduce the number of anesthesia sessions and is considered an alternative treatment for upper urinary tract calculi in selected pediatric patients younger than 3 years of age.

Comparison and Evaluation of Outcomes of Ureteroscopy and Stone Laser Fragmentation in Extremes of Age Groups (≤10 Years and ≥80 Years of Age): A Retrospective Comparative Analysis of over 15 Years from 2 Tertiary European Centres

AIM

To assess and compare the outcomes associated with ureteroscopy and laser fragmentation (URSL) for extremes of age group (≤10 and ≥80 years).

METHODS

Retrospective consecutive data were collected from two European centres for all paediatric patients ≤10 undergoing URSL over a 15-year period (group 1). It was compared to consecutive data for all patients ≥80 years (group 2). Data were collected for patient demographics, stone characteristics, operative details, and clinical outcomes.

RESULTS

A total of 168 patients had 201 URSL procedures during this time (74 and 94 patients in groups 1 and 2 respectively). The mean age and stone sizes were 6.1 years and 85 years, and 9.7 mm and 13 mm for groups 1 and 2 respectively. While the SFR was slightly higher in group 2 (92.5% versus 87.8%, p = 0.301), post-operative stent rate was also significantly higher in the geriatric population (75.9% versus 41.2%, p = 0.0001). There was also no significant difference in pre-operative stenting (p = 0.886), ureteric access sheath use (UAS) (p = 0.220) and post-operative complications. Group 1 had an intervention rate of 1.3/patient as compared to 1.1/patient in group 2. The overall complications were 7.2% and 15.3% in groups 1 and 2 respectively (0.069), with 1 Clavien IV complication related to post-operative sepsis and brief ICU admission in group 2.

CONCLUSION

The paediatric population had a marginally higher incidence of repeat procedure, but the overall SFR and complications were similar, and post-operative stent insertion rates were much better compared to geriatric patients. URSL is a safe procedure in the extremes of age groups with no difference in the overall outcomes between the two groups.

Cystatin C in Evaluating Renal Function in Ureteral Calculi Hydronephrosis in Adults

BACKGROUND

Serum cystatin C (CysC) is still becoming used as a marker of renal function but is far from being commonly used worldwide. The purpose of this study was to characterize the ureteral calculi patients with hydronephrosis-caused CysC changes in renal function.

METHODS

To better reflect the changes of renal function, we constructed models of ureteral obstruction in rats to mimic the hydronephrosis caused by human ureteral calculi. Moreover, our study included 200 patients diagnosed with ureteral calculi in our hospital between June 2017 and 2018. We compared the estimated glomerular filtration rate using different equations based on CysC and/or serum creatinine (SCr).

RESULTS

We found that the expression of CysC and SCr increased with the prolonged obstruction time by enzyme linked immunosorbent assay. Moreover, quantitative real-time polymerase chain reaction, Western blot and immunohistochemistry further demonstrated that the expression of CysC increases with the degree of hydronephrosis. Among 200 patients with ureteral calculi, 40 (20.0%) had no hydronephrosis, 110 (55.0%) had mild hydronephrosis, 32 (16.0%) had moderate hydronephrosis and 18 (9.0%) had severe hydronephrosis. As the degree of hydronephrosis increased, the expression of neutrophil percentage, CysC, blood urea nitrogen, SCr and serum uric acid also increased. Multivariate analyses demonstrated that only CysC was an independent risk factor for hydronephrosis (p = 0.003). In addition, CysC and the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) CysC equation showed the highest veracity in renal function estimation of patients with hydronephrosis caused by ureteral calculus.

CONCLUSION

For patients with hydronephrosis caused by ureteral calculi, CysC better reflects the changes in renal function, and the CKD-EPI CysC equation has the highest accuracy.

The Efficacy of Ultra-thin Semi-rigid Ureteroscopy with Holmium Laser Lithotripsy in Pediatric Ureteral Stones: A Single-center Experience

Introduction

The aim of this study was to present our results regarding the feasibility and possible complications of 4.5 Fr semi-rigid ureterorenoscopy (URS) treatments in pediatric patients.

Methods

The files and computer records of a total of 33 pediatric patients (20 males and 13 females), who underwent URS procedures for ureteral stones > 5 mm between January 2013 and June 2017, were retrospectively reviewed. A 4.5 Fr semi-rigid ureteroscope (Ultrathin 4.5/6.5 Fr Ureterorenoscope; Richard Wolf GmbH, Knittlingen, Germany) was used for the URS procedures. For the stone-free rate evaluations, abdominopelvic ultrasound or direct radiography scans were performed one week after the surgery, and low-dose non-contrast computed tomography (CT) was performed during the first month.

Results

The mean age of the patients was 9.8 ± 2.8 (range 4-16) years old, and the mean ureteral stone size was 8.9 ± 1.4 (range 6-13) mm. The mean surgical duration was 45 ± 21.2 (range 30-75) minutes, and the mean hospital stay length was 1.2 (range 1-4) days. Minor complications occurred in five (15.1%) of the patients. The success rates for the first week and first month were 90.9% and 96.9%, respectively.

Conclusion

The endoscopic management of pediatric ureteral stones using a 4.5 Fr ureteroscope seems to be a safe and feasible treatment option with high success and low complication rates.

Micro-ureteroscopy vs. ureteroscopy: effects of miniaturization on renal vascularization and intrapelvic pressure

PURPOSE

Ureteroscopy (URS) is related to complications, as fever or postoperative urinary sepsis, due to high intrapelvic pressure (IPP) during the procedure. Micro-ureteroscopy (m-URS) aims to reduce morbidity by miniaturizing the instrument. The objective of this study is to compare IPP and changes in renal haemodynamics, while performing m-URS vs. conventional URS.

METHODS

A porcine model involving 14 female pigs was used in this experimental study. Two surgeons performed 7 URS (8/9.8 Fr), for 45 min, and 7 m-URS (4.85 Fr), for 60 min, representing a total of 28 procedures in 14 animals. A catheter pressure transducer measured IPP every 5 min. Haemodynamic parameters were evaluated by Doppler ultrasound. The volume of irrigation fluid employed in each procedure was also measured.

RESULTS

The range of average pressures was 5.08-14.1 mmHg in the m-URS group and 6.08-20.64 mmHg in the URS (NS). 30 mmHg of IPP were not reached in 90% of renal units examined with m-URS, as compared to 65% of renal units in the URS group. Mean peak diastolic velocity decreased from 15.93 to 15.22 cm/s (NS) in the URS group and from 19.26 to 12.87 cm/s in the m-URS group (p < 0.01). Mean resistive index increased in both groups (p < 0.01). Irrigation fluid volume used was 485 mL in the m-URS group and 1475 mL in the URS group (p < 0.001).

CONCLUSIONS

m-URS requires less saline irrigation volumes than the conventional ureteroscopy and increases renal IPP to a lesser extent.

Outcomes of ureteroscopy miniaturization on tissue damage and tissue hypoxia in a pig model

Miniaturization of ureteroscopy materials is intended to decrease tissue damage. However, tissue hypoxia and the gross and microscopic effects on tissue have not been adequately assessed. We compared the gross and microscopic effects of micro-ureteroscopy (m-URS) and conventional ureteroscopy (URS) on the urinary tract. We employed 14 pigs of the Large White race. URS was performed in one of the ureters with an 8/9.8 F ureteroscope, while a 4.85 F m-URS sheath was used in the contralateral ureter. Gross assessment of ureteral wall damage and ureteral orifice damage was performed. For microscopic assessment hematoxylin-eosin staining and immunohistochemistry for detection of tissue hypoxia were conducted. Regarding the macroscopic assessment of ureteral damage, substantial and significant differences were recorded using URS (C = 0.8), but not with m-URS. Microscopic assessment after staining with hematoxylin-eosin revealed greater epithelial desquamation in the URS group (p < 0.05). Pimonidazole staining revealed greater hypoxia in the epithelial cells than in the remainder of the ureteral layers. We conclude that m-URS causes less damage to the ureteral orifice than URS. Histopathological findings show m-URS reduces ureteral epithelial damage compared with conventional ureteroscopy. Both URS and m-URS cause cellular hypoxia.

Ureteroscopy for Stone Disease in Paediatric Population is Safe and Effective in Medium-Volume and High-Volume Centres: Evidence from a Systematic Review

Purpose of Review

The incidence of urinary stone disease among the paediatric population is increasing. Whilst there has been a rise in the number of original studies published on ureteroscopy (URS) in children, critical review still remains under-reported.

Recent Findings

A Cochrane style systematic review was performed to identify all original articles on URS (minimum of 25 cases) for stone disease in paediatric patients between Jan. 1996 and Dec. 2016. Based on the number of reported cases, centres were divided into medium (25–49 cases) and high (≥ 50 cases) volume studies.

Thirty-four studies (2758 children) satisfied our search criteria and were included in this review. The mean stone size was 8.6 mm with an overall stone-free rate (SFR) of 90.4% (range 58–100). Medium-volume centres reported a mean SFR of 94.1% (range 87.5–100), whilst high-volume centres reported a mean SFR of 88.1% (range 58–98.5). Mean number of sessions to achieve stone-free status in medium-volume and high-volume groups was 1.1 and 1.2 procedures/patient respectively. The overall complication rate was 11.1% (327/2994). Breakdown by Clavien grade was as follows: Clavien I 69% and Clavien II/III 31%. There were no Clavien IV/V complications, and no mortality was recorded across any of the studies. The overall failure to access rate was 2.5% (76/2944).

Medium-volume and high-volume studies had overall complication rates of 6.9% (37/530) and 12.1% (287/2222) respectively, but there was no significant difference in major or minor complications between these two groups.

Summary

Ureteroscopy is a safe and effective treatment for paediatric stone disease. Medium-volume centres can achieve equally high SFRs and safety profiles as high-volume centres. Despite the rarity of paediatric stone disease, our findings might increase the uptake of paediatric URS procedures.