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Surgical Treatment of Renal and Ureteral Stones PowerPoint Presentation
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Surgical Treatment of Renal and Ureteral Stones

Surgical Treatment of Renal and Ureteral Stones

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Surgical Treatment of Renal and Ureteral Stones

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  1. Surgical Treatment of Renal and Ureteral Stones Herb Wiser

  2. Treatment Modalities • ESWL (extracorporeal shock wave lithotripsy) • Ureteroscopy • PCNL (percutaneousnephrolithotomy) • Open or laparoscopic surgery • Ureterolithotomy • Anatrophicnephrolithtomy

  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

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

  5. Mechanism of Action – Electrohydraulic • Power source at F1 • Generated in water medium • Contained in a ellipsoid shield • Waves (energy) concentrated at F2

  6. Prognostic factors for ESWL success Wang LJ et al. EurUrol 2005 • <900 HU (72% success) vs >900 (35%) • Size <12mm (78%) vs >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

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

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

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

  10. Complications of ESWL

  11. Complications of ESWL • Pain from stone fragment passage • 25-50% of pts • Steinstrasse • ~5% of pts http://radiologyinthai.blogspot.com/2010_12_01_archive.html

  12. 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)

  13. 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)

  14. Ureteroscopes

  15. Flexible Ureteroscopy http://www.windsorurology.co.uk/ Grasso M. Arch EspUrol 2008.

  16. Image Quality

  17. Laser Lithotripsy

  18. Laser Lithotripsy

  19. Stone Basketing

  20. 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

  21. 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

  22. 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%

  23. 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

  24. 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

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

  26. Percutaneous Approach • Big stones (>2cm) • Stones likely to be struvite • Difficult anatomy (calycealdiverticulum, etc) • ESWL failures

  27. PCNL

  28. http://www.actasurologicas.info

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

  30. 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

  31. 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

  32. 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

  33. 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

  34. Contraindications to PCNL • UTI • Coagulopathy • No safe access possible