Shockwave lithotripsy for kidney stones as a first-line therapy in children younger than 2 years

A systematic review of nomograms used in urolithiasis practice to predict clinical outcomes in paediatric patients

INTRODUCTION

Nomograms, used to predict the risk and success of treatment of urinary tract stones, are being used in paediatric clinical practice. However, no studies have determined the best prediction model. This study aimed to identify the most robust nomogram(s) for predicting clinically relevant outcomes in urinary stone disease in paediatric patients.

METHODS

The EMBASE, MEDLINE, Cochrane Systematic Reviews, and Cochrane Central Register of Controlled Trials via Ovid were searched for publications on May 13, 2021. No study design and publication year limitations were applied. The risk of bias in the included studies was determined using PROBAST.

RESULTS

The review included fourteen studies, involving 3888 paediatric patients. We identified seven prognostic stone nomograms (Dogan, Onal, CMUN, SKS, Guy's stone score, S.T.O.N.E and CROES) that were validated for use in paediatric patients. Both Dogan and Onal scores were developed and internally and externally validated in different studies with similar AUC scores between 0.6 and 0.7. For PCNL practice, two nomograms were developed and internally validated (CMUN, SKS) but not externally validated. The Guy's stone score was found to have the lowest overall accuracy in predicting stone-free rates in the externally validated nomograms studies. Nine of the fourteen studies included were judged as having a high risk of bias in their overall judgement.

CONCLUSION

The systematic review findings should be interpreted with caution given the heterogeneity of included studies. There is no difference between the use of the Dogan or Onal score for predicting outcomes associated with ESWL. For predicting outcomes of PCNL, CROES had the greatest supportive evidence, whilst the SKS or CMUN scores lack external validation and require further evaluation to assess their utility in predicting PCNL outcomes.

Extracorporeal shock wave lithotripsy in Indian children: Predictors of outcome and validation of pre-treatment nomograms

BACKGROUND

Although multiple variables have been shown to affect outcomes in pediatric lithotripsy (ESWL), there is no consensus on the same. Nomograms combine multiple variables and provide an objective prediction of outcomes. Two nomograms have been previously described and validated in two studies from the same geographical area. External validation in multiple settings is needed, as a nomogram's performance may vary with time, geographical area and clinical scenario.

OBJECTIVES

This study aimed to identify variables influencing pediatric ESWL outcomes, validate published nomograms and describe the clinical and metabolic profile of Indian children treated with ESWL.

DESIGN

This retrospective cohort study included all children who underwent ESWL from 2002 to 2019 at a single centre. ESWL was performed under general anaesthesia. Mid and lower ureteric calculi were treated in prone and the rest in supine position. 1500-2000 shocks were delivered at a voltage of 12-16 kV. Data pertaining to patient characteristics, metabolic evaluation, imaging, ESWL details and post-procedure outcomes were obtained from the hospital information system and these variables, along with Onal and Doğan scores, were correlated with stone clearance. Cut-offs for Onal and Doğan scores were determined using receiver operator characteristic (ROC) curve analysis and compared with area under the curve (AUC). Complications, ancillary procedures and metabolic abnormalities were recorded.

RESULTS

A total of 66 children (76 renal units) were included. Mean age was 5.5 years (Range 6 months-14 years) and median stone size, 12 mm (IQR 9, 15.25). Average treatment sessions were 1.8 ± 0.99. Median shocks in the stone-free group and those who failed treatment were 1750 (IQR 1500, 3000) and 3250 (IQR 1750, 4750) respectively. The remaining variables are depicted in Table 1. The stone free rate was 63.2%. Fragments <4 mm were seen in 19 (25%). Efficacy Quotient was 40. The AUC for Doğan nomogram (cut-off <199.5) was 0.761 while that for Onal nomogram (cut-off <2.5) was 0.762 and 0.771 after one and three shocks respectively. On multivariate analysis, age, multiple calculi, Onal and Doğan scores were predictive of clearance. Doğan score had higher specificity. Complications were seen in 16 (21%) and ancillary procedures needed in 7 (9.2%). Metabolic abnormalities were seen in 84.8%, the commonest being hyperoxaluria. Mixed stones were most frequent.

CONCLUSIONS

Lithotripsy in children is safe and effective. Older age, presence of multiple calculi, higher Onal and Doğan scores are predictive of treatment failure.

Comparison of extracorporeal shockwave lithotripsy and retrograde intrarenal surgery in the treatment of renal pelvic and proximal ureteral stones ≤2 cm in children

Introduction:

We aimed to compare extracorporeal shockwave lithotripsy (ESWL) and retrograde intrarenal surgery (RIRS) in pediatric patients with ≤2 cm renal pelvis and proximal ureteral stones.

Methods:

Medical records of 165 pediatric patients who underwent shockwave lithotripsy (SWL) or RIRS for upper urinary system stones up to 2 cm between January 2014 and December 2018 were retrospectively reviewed. After exclusions, the remaining 130 patients included 73 in the SWL group and 57 in the RIRS group. The groups were compared for demographic features, stone characteristics, operative data, success, and complications.

Results:

The mean stone volume was 308 ± 85 (54–800) and 336 ± 96 (60–720) mm³ in SWL and RIRS groups, respectively (P = 0.46). There were no significant differences in success rates (60% vs. 70%, SWL and RIRS), auxiliary treatment rates (16.4% vs. 14%), and complication rates (26% vs. 24.5%). The number of active procedural sessions and number of anesthesia sessions was higher in the RIRS group (P < 0.001 and P < 0.001, respectively), while the procedural time and anesthesia time were higher in the SWL group (P < 0.001 and P < 0.001, respectively). Stone size was found to be an independent success predictive factor for both the treatment modalities.

Conclusions:

Both SWL and RIRS have similar success, complication, and auxiliary treatment rates. RIRS was superior in terms of total procedure and anesthesia durations, while SWL was superior in terms of numbers of anesthesia sessions and active procedure sessions. As both have similar success rates, the more minimally invasive SWL should be chosen for pediatric upper urinary system stones of less than 2 cm size.