Operative note 11 Core Core/advanced
Flexible ureteroscopy for kidney stones
What it does: bendy scope up into the kidney. Laser the stone.
- GA with a tube. Breath holds = still kidney.
- Cystoscopy. Wire up the ureter under screening. Stop there: curl seen in the renal pelvis on the screen before anything follows it. That wire stays as the safety wire. Here: semirigid scope up beside it, second (working) wire through the scope into the renal pelvis under direct vision. Scope out over it.
- Empty the bladder. Stops scope coiling.
- Suction access sheath 10-14Ch over the wire under screening, dilator in. Length by sex: about 35 cm female, about 45 to 46 cm male (owner's typical values). Suction tubing on, suction off until the tip is in the kidney. Never force it: resistance = downsize, or stent and come back.
- Tip stopped at the renal pelvis on the image intensifier, not through the PUJ. Dilator and working wire out. Flexible scope up inside the sheath. Suction on once the tip is in the kidney.
- Saline only. In the kidney: water off.
- Map every calyx first: upper, middle, lower. Sure of the map? Straight to the stone. Not sure? Contrast 50:50 with saline outlines the pelvis and every calyx. Full-strength contrast hides small stones.
- Stone in the lower pole: open the basket beside it, around it, close it on the stone. Carry it to the renal pelvis or upper pole, release it, laser it there.
- Fibre stuck with the tip fully flexed in the lower pole? Never force it: pushing only straightens the tip off the target. Ease the flexion, back to the pelvis, fibre out of the channel, then flex again.
- Ho:YAG, owner's typical ranges: dusting 0.2 to 0.5 J at 20 to 40 Hz (about 4 to 20 W); fragmentation 0.8 to 1.2 J at 6 to 12 Hz (about 5 to 14 W); pop-dusting 0.3 to 0.5 J at 30 to 50 Hz (about 10 to 25 W). Dust first. Paint the stone.
- Tiny fragments: pop-dust them. Fibre held still above them in a confined calyx.
- Clearance: thumb on the suction port, sheath brought over the scope until the fragments are in view, scope withdrawn slowly to the marker with the suction running. The suction takes the fragments.
- TRAPPED BASKET (exam favourite): STOP. Never pull. Pulling tears the ureter off. Take the basket handle apart. Slide the scope off the basket wire. New wire past the stone, over the safety wire. Scope back alongside. Laser the stone. Still stuck? Stent 24 h. Dilates. Retry.
- 2026 update: No change in principle.
- 2026 update: Suction access sheath sequence, sheath lengths by sex and typical laser ranges added by the owner on 27 September 2026.
From the UroRef Operative Quick Guide.