Retrograde Intrarenal Surgery for Renal Stones in Pediatrics: A Prospective Analysis of Feasibility and Outcomes.
Phase: NA
Conditions: Renal Stones, Pediatric Renal Stones
Sponsor: Al-Azhar University

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Al Azhar university 
Faculty of medicine 
 
Urology department      
                               
 
Retrograde Intrarenal Surgery for Renal 
Stones in Children: A prospective Analysis of 
Feasibility and Outcomes 
 
 
 
 
 
 
Al-Azhar University 
  January 2023 
 
 
 
 
 
 
 
 
 
 
 
 
 

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INTRODUCTION: 
The incidence of paediatric urolithiasis is on a rising trend globally,[1] and the 
treatment of stones in children poses a major challenge. Percutaneous 
nephrolithotomy (PCNL) and shock-wave lithotripsy (SWL) are the established 
forms of treatment for children with renal stones. despite its non-invasive and 
safe nature, coupled with high stone-free rates in children, necessity of multiple 
sessions under anesthesia and increased radiation-exposure risk constitute 
major concerns for SWL in this specific population [2]. 
 On the other hand, published data, to date, have clearly demonstrated that 
despite excellent stone-free rates obtained in a single session along with 
ongoing miniaturization process, PNL has the greatest risk of major 
complications [3], [4], [5]. For this reason, PNL is generally reserved for 
stones >20 mm and for the ones when other treatment modalities have failed or 
would probably fail due to certain reasons [3], [4]. 
The acceptability and utilisation of the mini, ultramini and the micro PCNLs is 
on the rise and the complication rate of these procedures is comparable with 
the RIRS and is significantly low. Nevertheless, the complications such as the 
risk of bleeding requiring transfusion, pleural and visceral injury, although low, 
have 
not 
been 
completely 
eliminated, 
even 
with 
the 
miniaturized 
PCNLs[6,7,8,9]. 
RIRS has become an important treatment option for kidney stones in pediatric 
patients with the development of new-generation ureteroscopy and holmium 
laser. It is an effective method in the proximal ureter, collecting duct system, 
and, especially, lower calyx calculi[10]. 
Flexible ureteroscopy (FURS) has been applied in recent years to the treatment 
of urinary stones. FURS presents overt advantages over other techniques, 

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including improved resolution and increased optical field, high stone-free rate, 
reduced risk of bleeding, limited surgical injury, good repeatability, and speedy 
recovery; in addition, further miniaturization is possible[11–13]. In children 
and infants, who have a relatively high stone recurrence rate, FURS could be 
performed repeatedly [14]. 
• Several studies were conducted on RIRS for pediatric renal stones and proved 
its safety and efficacy. However, RIRS in pediatrics has crossed many 
milestones, yet many areas need further research, and larger data are required 
to make RIRS the procedure of choice for renal stone management in children . 
 
OBJECTIVE AND HYPOTHESIS: 
 
• In this study, we will evaluate the feasibility, stone-free rate, and complication 
rate of RIRS for renal stones in a pediatric population.  
• We hypothesize that miniaturized equipment allows experienced urologists to 
deal with pediatric renal stones safely and effectively . 
 
MATERIALS AND METHODS: 
• STUDY DESIGN: A Prospective, single-arm interventional study 
• STUDY SETTING:  Urology department/ Al-Hussein and Bab El’Sharia , Al-
Azhar University Hospitals 
• STUDY PERIOD: Two years 
• STUDY POPULATION: 
All children (≤18 years), with renal stones ≤ 2 cm indicated for treatment. 
 
Exclusion criteria: 
‐ Active urinary tract infection( UTI) 
-Uncorrectable coagulation disorders. 
‐ Concomitant pathology that need intervention in the same setting. 
-Stone in a calyceal diverticulum. 

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-Abnormal renal anatomy 
-Urinary tract obstruction distal to the stone. 
 
Informed written consent will be obtained from the patient parents before 
inclusion in the study. 
Parents should be told about the goals of the surgery, likely modifications 
during surgery, common complications and their treatments, period of 
hospitalization, postoperative protocol. 
• STUDY PROCEDURE: 
◊ Preoperative evaluation: 
‐ Medical history and physical examination 
‐ Urinalysis, CBC, and serum creatinine 
‐ Plain X-ray KUB and abdominal ultrasonography 
‐ Abdominal low-dose NCCT 
‐ Contrast imaging (CT or IVU), if detailed calyceal anatomy is needed. 
‐ Routine preoperative laboratory investigations and anesthetic workup. 
‐ Informed consent (Parental consent) 
◊ RIRS procedure: 
‐ General anesthesia 
‐ Prophylactic antibiotic 
‐ Preoperative stenting (DJ), near 2 wks before RIRS. 
‐ Without ureteral access sheath 
‐ Under direct visualization and/or fluoroscopy guidance. 
‐ Disposable flexible ureteroscope 8.6 Fr / 7.5 Fr, and Ho. YAG Laser for stone 
disintegration. 
‐ PO ureteral stenting: external ureteric catheter or DJ stent. 
◊ Postoperative evaluation and follow-up: 
➢ 1st PO day: 
‐ Monitoring of general condition, vital signs, and urine colour 

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‐ CBC, abdominal USG and plain X-ray KUB 
‐ Removal of urethral catheter ± Ureteric catheter, if patient is generally stable 
with clear urine. 
‐ Patient will be discharged home on oral antibiotic and on demand analgesic. 
➢ 2nd PO week and 2nd PO month: 
‐ History and Ex., urinalysis, s. creatinine, abdominal USG and plain X-ray 
KUB or NCCT. 
• The need for another lab or imaging studies or 2 nd RIRS session and time of 
DJ removal will be decided according to the PO follow-up findings. 
• DJ will be removed after 2 weeks if (uncomplicated + Stone free). 
▪ STUDY PARAMETERS 
◊ Demographic data and preoperative 
clinical characteristics 
◊ Scope-to-stone access 
◊ Operative time 
◊ Fluoroscopy time 
◊ Postoperative ureteral stenting method 
◊ Intra- and post-operative complications 
◊ Hospitalization time 
◊ Postoperative pain (young children) 
◊ Analgesic dosage 
◊ Unscheduled hospital visits 
◊ Reintervention 
◊ Rehospitalization 
 
 
 
 
 

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Results: 
▪ Data analysis 
◊ The 1ry end points are the feasibility of the technique (as evaluated by scope  
to-stone access rate) and SFR (as evaluated by postoperative imaging studies, 
2 months after surgery). 
◊ Patients will be stratified into 3 groups  if sufficient (1) Infants and preschool 
children (upto 6 yrs); (2) Primary school children (>6 – 12 yrs); and Young 
children (>12 –18 yrs). 
◊ The feasibility and outcomes of RIRS, overall and in each group, will be 
Analyzed  using the SPSS program. 
Data Will be analyzed using Statistical Program for Social Science (SPSS) 
version 24.  Qualitative data were expressed as frequency and percentage. 
Quantitative data were expressed as mean ±SD. Mean (average): the central 
value of a discrete set of numbers, specifically the sum of values divided by the 
number of values. Standard deviation (SD): is the measure of dispersion of a 
set of values. A low SD indicates that the values tend to be close to the mean of 
the set, while a high SD indicate that the values are spread out over a wider 
range. 
The following tests will be done: 
• A one-way analysis of variance (ANOVA): when comparing  more than two 
groups. 
• Chi-square test: will be used when comparing  categorized data. 
• Probability (P-value)  
– P-value < 0.05 was considered significant. 
– P-value < 0.001 was considered as highly significant. 
– P-value > 0.05 was considered insignificant. 
 
 
 

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DISCUSSION:  
 
SUMMERY & CONCLUSION: 
 
ARABIC SUMMARY: 
 
References: 
1)Clayton DB, Pope JC. The increasing pediatric stone disease problem. Ther 
Adv Urol. 2011;3:3–12.  
2)Straub M.Gschwend J.Zorn C.Pediatric urolithiasis: the current surgical 
management.Pediatr Nephrol. 2010; 25: 1239-1244. 
3) Kumar R. Anand A. Saxena V. Seth A .Dogra P.N. Gupta N.P. Safety and 
efficacy of  PCNL  for management of staghorn  calculi in pediatric patients.J 
Pediatr Urol. 2011; 7: 248-251. 
4) Bilen C.Y. Gunay M. Ozden E. Inci K. Sarikaya S. Tekgul S. Tubeless mini 
percutaneous nephrolithotomy in infants and preschool children: a preliminary 
report.J Urol. 2010; 184: 2498-2503. 
5) Helal M. Black T. Lockhart J. Figueroa T.E. The Hickman peel-away sheath: 
alternative for pediatric percutaneous nephrolithotomy. J Endourol. 1997; 11: 
171-172. 
6)Sen H, Seckiner I, Bayrak O, Dogan K, Erturhan S. A comparison of micro-
PERC and retrograde intrarenal surgery results in pediatric patients with renal 
stones. J Pediatr Urol. 2017;13:619.e1. 
7)Ozden E, Mercimek MN. Percutaneous nephrolithotomy in pediatric age 
group: Assessment of effectiveness and complications. World J Nephrol. 
2016;5:84–9. 
8)Hong Y, Xu Q, Huang X, Zhu Z, Yang Q, An L. Ultrasound-guided minimally 
invasive percutaneous nephrolithotomy in the treatment of pediatric patients <6 

8 
 
years: A single-center 10 years' experience. Medicine (Baltimore) 
2018;97:e0174. 
9) Michel MS, Trojan L, Rassweiler JJ. Complications in percutaneous 
nephrolithotomy. Eur Urol. 2007;51:899–906. 
10)Önen A: Minimally invasive approach to pediatric urinary stones. [Article in 
English]. Journal of Pediatric Surgery. 2016, 30:15664. 
11) Almeras C, Daudon M, Ploussard G, et al. Endoscopic description of renal 
papillary abnormalities in stone disease by flexible ureteroscopy: A proposed 
classification of severity and type. World J Urol. 2016;34:1575–82. doi: 
10.1007/s00345-016-1814-6. 
12) Zhu X, Song L, Xie D, et al. Animal experimental study to test application of 
intelligent pressure control device in monitoring and control of renal pelvic 
pressure during flexible ureteroscopy. Urology. 2016;91:242.e11–5. 
13) Rassweiler J, Rassweiler MC, Klein J. New technology in ureteroscopy and 
percutaneous nephrolithotomy. Curr Opin Urol. 2016;26:95–106. doi: 
10.1097/MOU.0000000000000240. 
14)Oral I, Nalbant I, Ozturk U, et al. Our experience with percutaneous 
nephrolithotomy in pediatric renal stone disease. Turk J Urol. 2013;39:35–8. 
doi: 10.5152/tud.2013.007.