Ureteroscopic lithotripsy (URSL)

Ureteroscopic lithotripsy (URSL) for ureteric calculi

1. Operative Chat Ureteroscopic Lithotripsy URSL Dr. Abhishek Pandey

2. Pre-Treatment Assessment Stone Factors – Location – Proximal-Mid vs Distal Stone Burden – 97% success for ≤1cm; 93% success for >1cm Stone Composition – success not affected Anatomical Factors – Megaureter – Endoureterotomy in <3cm segment → URSL Duplicated Collecting System – RGP → URSL Ureteral Stricture / Stenosis – Dilatation / Endoureterotomy

3. Patient Factors – UTI – negative culture obtained before procedure Renal Function – symptomatic upper tract stones + ≤15% spilt function consider nephrectomy Solitary Kidney – treat asymptomatic stones Morbid Obesity – URSL success & safety independent of BMI Spine deformity / Limb contracture – Flexible URS Coagulopathy – URS + Ho:YAG lithotripsy → Rx of choice Duration of obstructing ureteral stone – treat if persistent for 4w

4. Patient & Equipment positioning Lithotomy position with liberal padding Flexible URS feasible in supine / lateral decubitus positions Table should be radiolucent Fluoroscopy – Fixed all-in-one table / Portable C-arm unit Two irrigation bags – 1 ↓ gravity & 1 in pressure bag\ Laser console as close to surgeon as possible Surgeon can sit / stand

5. Guidewires Guide to access / dilation / stent placement. Diameter – 0.018-0.038 inch – most common 0.038inch Length – 80-260 cm – most common 145cm Distal tip – Straight / Angled / J-tipped ; floppy for 1-3cm Nitinol core wire – kink-resistant & stiffer Glide wires – Hydrophilic coated wires instead of PTFE Hybrid guidewires – hydrophilic tip & PTFE shaft

6. Ureteral Catheters Length usually 70cm with markings at every 5cm. Straight tip catheters – 5 or 6 Fr

7. Dilation devices Passive dilation – pre- stenting for ≥ 7days before URSL Active dilation – Dilating catheters – hydrophilic coated polyurethane tapered catheters Balloon dilator – filled with diluted radiocontrast

8. Ureteral Access Sheath Placed over guidewire under fluoroscopic guidance Facilitate flexible URS Useful for repeated entries – stone fragment retrieval Decrease renal perfusion pressure Increase irrigation flow → improve vision Inner dilator & outer sheath

9. Ureteroscopes Semirigid Ureteroscope Larger working channels Less prone to damage Length – Short (females) or Long (males) Tip diameter ≤7Fr Eye-piece – in-line / off-set (straight working channel in off-set) Working channel – single / double Easy to reach till ureter cross iliac vessels

10. Flexible ureteroscopes Types – Fiberoptic – Fiberoptic bundles carry light & image Digital – “Chip on tip” – digital image, ↑ tip diameter Deflection mechanism – plane of deflection marked by reticle – scope rotated to align the plane of deflection with the intended target Intuitive or counter-intuitive deflection with respect to the lever Deflection ≥180° achieved

11. Intracorporeal Lithotriptors Pneumatic – requires semirigid URS with a straight working channel (offset eye-piece) – retropulsion EHL – Flexible but more damaging Ho:YAG laser – Intraluminal lithotripsy energy of choice – dusting of stone by photothermal effect

12. Stone retrieval devices Three-pronged stone grasping forceps – safest Stone baskets – Helical baskets / Flat-wire baskets Surgeon should be able to see the endoscope, stone & ureter during extraction Nitinol alloy baskets – memory, maintain shape, resist kinking

13. Retropulsion prevention devices prevent migration of distal ureter stones ( semirigid URS) into proximal ureter (flexible URS)

14. Ureteral stents - Drainage Double-J (DJ) stents Routine stenting has no beneficial effect on stone-free rates or ureteral stricture rates Quality of life better in non- stented patients Indwelling-time <14days → fewer adverse effects Placing stent for 1-2 weeks after initial unsuccessful URSL leads to higher success rate of secondary URSL

15. URSL Procedure Rigid cystoscopy to identify ureteral orifice 5Fr open ended catheter over guidewire → Perform RGP Place a safety guidewire up to kidney ↓ fluoroscopic guidance If a glidewire is used, replace with stiffer wire If pus encountered – send culture, abandon & place a stent Drain the bladder before commencing URS Intermittent / continuous bladder drainage during procedure

16. Access in narrow ureteral orifice Railroad technique – second guidewire passed to tent open the narrow ureteral orifice ↓ fluoroscopic guidance → ureteroscope advanced between the wires

17. Dilation – if access unsuccessful after rail-road technique Do NOT dilate over the stone → ureteral trauma, stone extrusion If unsuccessful dilation → 2° URSL after ≥1w stenting

18. Lower Ureteral stones Semirigid Ureteroscope Ureteral occluding devices used to prevent retropulsion of calculi into proximal ureter → deployed above the stone under vision → URS repassed alongside it Lithotripsy – Dusting – Ho:YAG laser Fragmentation → complete basket extraction under direct vision without using undue force

19. Laser lithotripsy – activate when tip in contact with stone Soft stones – start at 0.2 J & 50 Hz → Dusting Hard stones – start at 0.6 J & 6 Hz → gradual fragmentation, minimising retropulsion Inspect ureter after lithotripsy – verify stone clearance Identify ureteral injury RGP at the end of procedure Stent may be placed with / without tether

20. Upper Ureteral stones Semirigid often not practical in males For flexible URS → place 2 guidewires – safety & working Pass flexible URS over working wire ↓ fluoroscopic guidance Ureteral access sheaths used for high proximal stones → passed over guidewire ↓ fluoroscopic guidance Access sheath should NOT be forced Or passed over the stone; risk of ureteral trauma & stone extrusion If access sheath not passable → proceed without it / stent

21. Complications Perforation – 0-4% case Splitting after balloon dilation Forceful placement of ureteral access sheath Placing dilator / access sheath over stone Forceful pulling of basket devices Direct injury by lithotrites – highest with EHL Pressurized irrigation – perforation / calyceal rupture Abandon the procedure & place a stent over safety guidewire

22. Stricture – 3-6% Impacted stones Ureteral perforation – 6% stricture rates Prior ureteral surgery Pelvic radiation 0.4-4% are asymptomatic Recommendation for all patients to undergo postoperative imaging after ureteroscopic instrumentation

23. Stone extrusion – 2% Submucosal stone – laser excision → ureteral stent Complete extrusion / lost stone – in ureteral perforation → abandon & place stent (do NOT attempt to retrieve the stone) Avulsion – 0.06-0.5% Forceful manipulation of large / impacted stone Avulsion at scope withdrawal (scabbard effect)

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