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1. Pediatric stone disease Daniel Tamirat MD,PSR 5 8/14/2022 1

2. Outline Introduction Evaluation Management Follow-up 8/14/2022 2

3. Introduction Children account for only 2%–3% of all patients with calculous disease Change in epidemiology (lower to upper tract stones, increasing incidence) M vs F ( occurrence, site ) mean age at presentation is 6.9 years for girls and 5.2 years for boys Etiology Metabolic, anatomic, dietary, genetic rate of recurrence of stones is as high as 40%–70% 8/14/2022 3

4. Stone classification Evolving treatment options and techniques 8/14/2022 4

5. CLINICAL PRESENTATION dependent on a number of factors: Size of the stone Location of the stone Degree of obstruction to the flow of urine Presence of infection Presence or absence of a normal contralateral renal unit Age 8/14/2022 5

6. Evaluation Hx Prematurity- supplemental vitamin D,, medications, Concurrent illnesses, Recurrent skeletal fractures, Nutritional habits, Family history of nephrolithiasis, gout, or bowel disease, gastrointestinal disorders P/Ex failure to thrive Hypertension as an indicator of underlying renal parenchymal injury characteristic bony deformities of rickets evidence of UTI 8/14/2022 6

7. Pathophysiology major factors are supersaturation of lithogenic ions and crystallization of compounds in the urine Formation of stones is influenced by urinary volume, pH, and the presence of urinary ions or compounds that function as promoters or inhibitors of lithogenesis central event in calculus formation is supersaturation 8/14/2022 7

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9. Evaluation cont. Workup Laboratory Metabolic workup (all) Blood and 24hr urine( Cr,Na,Ca,Oxalate,Citrate,uric acid). Standard reference range? Random spot urine sample (Uca/ Ucr ) Limitations? Imaging. Requirement? Spiral unenhanced CT (Collimation, sensitivity, radiation safety/dose, indications) US (sensitivity, safety, acute attach-miss) KUB (radiopaque stones) C arm fluoroscopy (Dx, Mgt, Concern) 8/14/2022 9

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11. Management Goal Stone free/extraction Prevent recurrence Mgt Conservative (When, Medical expulsive therapy) Intervention (endourology/Laparoscopic/robotic/Open) Indication Symptom, complication, failed conservative management 8/14/2022 11

12. Management of upper tract calculi Pediatric considerations Goal of rx (Stone free, prevent recurrence) Options ( ESWL, Ureteroscope, PCNL, Combined) Concern ( safety and complications SWL, ureteroscope) ?International consensus on the most effective/preferred treatment option for upper tract stones Residual fragments (adverse effect on outcome) 8/14/2022 12

13. Antibiotic use Urine should be sterile before any upper tract procedures Urine culture ( +ve/-ve), preop prophylactic abcs, Postop abcs ?prolonged use) 8/14/2022 13

14. Shock wave lithotripsy 8/14/2022 14

15. Shock wave lithotripsy cont. Indication Uncomplicated renal and upper tract stones size less than 1.5cm Size cutoff? GA/sedation Number of shockwaves and KV differ SWL Lower pole stones (success rate 50-60%, retreatment 40%, anatomic factors) Staghorn calculi (stone free rate 82%, higher than adults) Stone composition (Cystine, calcium oxalate, brush, matrix) 8/14/2022 15

16. Shock wave lithotripsy cont. Limitations/concerns Stone free rate ff single session monotherapy (44%) req re treatment ?Risk of HTN, DM ?Long term renal, gonadal, or pancreatic impairment ?Renal scarring and functional impairment 8/14/2022 16

17. Ureteroscopic management of upper tract calculi 8/14/2022 17

18. Ureteroscopic management of upper tract calculi Similar low complication rate as SWL and enhanced stone free rate Single session stone free rate (94%) Indications Historical (distal stones below iliac crest, failed SWL) Prev not considered for primary rx of upper tract stones Small ureteral caliber Safe; entire pediatric urinary tract 8/14/2022 18

19. Ureteroscopy cont. Relative contraindications Staghorn stone in recurrent stone formers Failed endoscopic management Anatomy (retrograde access or stone passage) Limitations and complications unrecognized ureteral injury, including mucosal flaps and tears, perforation, false passage, and partial to complete avulsion Mitigating damage Stent before/after the procedure…Debated 8/14/2022 19

20. Percutaneous nephrolithotomy/PCNL 8/14/2022 20

21. Percutaneous nephrolithotomy/PCNL Safety and efficacy in children Use of adult size equipment in children 68-100% stone free rate (Monotherapy/sandwich therapy with SWL) Relative indications Upper tract stone above 1.5cm Lower pole stone above 1cm Retrograde access/urinary drainage impair anatomy Stone composition (cystine and struviate ) 8/14/2022 21

22. PCNL cont. Intracorporal lithotripsy Four energy sources Electrohydrolic Pneumatic/ballistic Ultrasonic Holmium-YAG laser 8/14/2022 22

23. Planning for PCNL in children Film Stone amenable for percutaneous procedure Nephrocalcinosis (image, endoscopy, management) Image 8/14/2022 23

24. PCNL cont. Staghorn calculi Cause: infection First line treatment: PCNL Risks associated with percutaneous procedures Bleeding, hemo /hydro/ urothorax , adjacent structure injury, incomplete stone removal, sepsis Outcome Monotherapy, sandwich therapy Endoscopic surveillance during the initial procedure 8/14/2022 24

25. Laparoscopic and robotic assisted pyelolithotomy Efficacy, safety and feasibility in children Technically demanding Indication Failed endoscopic management Concomitant PUJO Renal anatomy precludes endoscopic/percutaneous intervention 8/14/2022 25

26. Silent obstruction and other considerations Adults Reduced renal function, no further deterioration after stone removal (Adults) No evidence in children Relative indication for surgical intervention 8/14/2022 26

27. Stone free status following definitive rx Adverse effect of residual stones Definition; no consensus 8/14/2022 27

28. Follow-up US: hydronephrosis sens 85% and specificity 97% KUB: residual fragments IVP? Timing With in 3 mo after surgery With in 6 weeks after surgery Surveillance CT Not routine Based on age, anatomy, stone burden, and underlying metabolic d/o 8/14/2022 28

29. Conclusion Pediatric stone disease treatment is evolving Effect on developing kidney: Safety concern Prospective studies: preferred endourologic approach 8/14/2022 29

30. The cornerstones for preventing stone recurrence as the child enters adulthood are the ability to render the patient stone free elucidate and treat metabolic abnormalities control urinary infection, and correct anatomic anomalies. 8/14/2022 30

31. Reference 8/14/2022 31