1. Surgical Treatment of Renal and Ureteral Stones Herb Wiser

2. Treatment Modalities ESWL (extracorporeal shock wave lithotripsy) Ureteroscopy PCNL (percutaneous nephrolithotomy) Open or laparoscopic surgery – Ureterolithotomy – Anatrophic nephrolithtomy

3. ESWL “Bath tub” treatment Shock waves to break stones Non-invasive Results worse for Bigger stones Stones located in the lower pole of the kidney Hard stones

6. Electrohydrolic (Spark gap) Electromagnetic Piezoelectric Energy Sources and Configurations

7. Mechanism of Action – Electrohydraulic Power source at F 1 Generated in water medium Contained in a ellipsoid shield Waves (energy) concentrated at F 2

9. Prognostic factors for ESWL success Wang LJ et al. Eur Urol 2005 900 (35%) Size 12 (26%) Non-Lower pole (70%) vs Lower pole (46%) Pareek G et al. Urology 2005 24/29 pts (83%) with SSD <10cm were stone free 6/35 pts (17%) with SSD >10cm were stone free

10. Success Rates ESWL Renal - 55-75% (lowest for lower pole stones) Proximal Ureter – <1cm – 90% – >1cm – 70% Mid/Distal Ureter – <1cm – 85% – >1cm – 75%

11. Contraindications to ESWL Pregnancy Coagulopathy UTI Intrarenal vascular calcifications Renal artery aneurysm or AAA

12. Complications of ESWL Retroperitoneal Hematoma – >25% incidence on imaging – <0.5% clinically significant

13. Complications of ESWL

14. Pain from stone fragment passage – 25-50% of pts Steinstrasse – ~5% of pts http://radiologyinthai.blogspot.co m/2010_12_01_archive.html

15. Complications of ESWL ? Long term effects of ESWL – DM and HTN – Retrospective studies show increased incidence of DM and HTN in stone formers – Is this because a stone formers have worse dietary habits? – Prospective trials show no increase in DM/HTN, but follow up is limited (a few years)

16. Ureteroscopy Placing small scope into ureter or kidney Flexible or rigid scopes Remove the stone (‘basket’, ‘loop’, ‘snare’) Break the stone - Laser May leave a stent (surgeon’s discretion)

17. Uretero scopes

18. Flexible Ureteroscopy Grasso M. Arch Esp Urol 2008. http://www.windsorurology.co.uk/

19. Image Quality

20. Laser Lithotripsy

22. Stone Basketing

23. Ureteroscope Considerations Flexible Scope outer sizes 8.5-10 Fr – Working channel 3.5Fr Semirigid Scope @ tip 7-9 Fr proximally 6-13.5 Fr one is 4.5/6.5 Fr – Working channel up to 3-6 Fr

24. Laser Lithotripsy Holmium:YAG laser is most common type for laser lithotripsy – Erbium:YAG and Thulium lasers under development, potentially superior to Ho:YAG, not widespread – Very limited depth of penetration (0.4mm) Limits tissue damage – Highly effective at lithotripsy

25. Success Rates Ureteroscopy – Old Data Renal - ~70-80% (lowest for lower pole stones) – Stone clearance decreases with increasing stone size Proximal Ureter - ~80% Mid Ureter – 80-90% Distal Ureter - ~95%

26. Complications of URS Ureteral Perforation – ~5% – Treatment is stenting (~6 weeks) – Can result in stricture in the long term (1% of all URS) Ureteral Stricture – Could be due to stone or URS Ureteral Avulsion – Rare but really, really bad

27. Stents Polymer tubes from kidney to bladder Keep the ureter open Dilates the ureter Patient removal vs surgeon removal Symptoms – Bladder spasms – Flank pain – hematuria

31. Stents People generally HATE them, but they are a necessary evil.

32. Percutaneous Approach Big stones (>2cm) Stones likely to be struvite Difficult anatomy (calyceal diverticulum, etc) ESWL failures

33. PCNL

35. http://www.actasurologicas.info

40. Lithotripsy for PCNL Ultrasonic Lithotriptor Pneumatic Lithotriptor Laser (Ho:YAG)

41. Ultrasonic Lithotriptor Electric current stimulates piezoelectric crystal Crystals expand and contract Creates vibrations at ~25,000 Hz Transmitted to tip of probe “Drills” the stone Strictly mechanical energy No heat, cavitation or shock waves Suctions fragments through the center of the wand

43. Pneumatic Lithotripsy Like a jackhammer Depression of foot pedal forces compressed air to handpiece Metal projectile is propelled Repetitive mechanical pounding Mechanical energy transferred to tip Fragmentation by compression forces

45. Success Rates PCNL Renal stones (even staghorns) – 80-90% Proximal ureteral stones – 85% Stone clearance rates are affected by renal anatomy and adequacy of access

46. Access for PCNL In the US – 80-90% by IR – 10-20% by urology – When IR involved, can be just for initial PCN tube or they may also dilate the tract and place the final PCN tube, highly variable

50. Contraindications to PCNL UTI Coagulopathy No safe access possible

51. Complications of PCNL Bleeding – Kidney is very vascular – each one gets 10% of cardiac output

53. Complications of PCNL Sepsis – highest risk is with infection stones (struvite) Pneumo/Hydrothorax – Highest risk with upper pole puncture Up to 10% of upper pole punctures in some studies Colon/Spleen injury – Very rare

54. Laparoscopy / Open Rarely necessary in 2009 Can use for extreme cases where compliance is a concern Higher morbidity, worse cosmesis, longer recovery

55. Questions?