UrOops3D, danger-zone atlas
Operative animation, URSL

Ureteroscopy + laser lithotripsy

Retrograde from the bladder to an impacted ureteric stone: a safety wire first, a second wire through the semirigid scope, the ureter tented on both and the scope railroaded up.

Holmium or thulium dusting, never large fragments; clearance by gravity with a basket only if needed; a JJ stent only when the ureter needs one. The wall is thinnest where the stone has sat longest, and that is where it tears.

Core tier FRCS endourology, stone disease Interactive 3D

Operative visualisation

Schematic scene preview: Ureteroscopy + laser
Preparing the 3D anatomy…

UrOops3D · UroRef · © Nity G

The scopes and the two wires

Semirigid ureteroscopes, working channels and the two wires Two semirigid scopes drawn to relative scale: a fine scope with a 6 French tip and a shaft to 7.5 French, and a standard scope with an 8 French tip and a shaft to 10 French. Cross-sections show one 3.6 French working channel, or two channels of about 2.4 and 3.4 French. The teal safety wire is placed first up the centre and stays; the white working wire runs through the scope channel and guides the scope. Four steps: bladder view and safety wire; second wire through the scope; tent on both wires and railroad to the stone; dust gently, clear by gravity, basket if needed. Semirigid scopes Fine: tip 6 Fr, shaft to 7.5 Fr Standard: tip 8 Fr, shaft to 10 Fr Working length about 33 cm (women), 43 to 45 cm (men) Working channel One 3.6 Fr channel or two, about 2.4 and 3.4 Fr Wire first, then the fibre or the basket Safety wire: centre, placed first, stays Working wire: in the channel, guides it 1Bladder view,safety wire up 2Second wirethrough the scope 3Tent on both,railroad to stone 4Dust gently,gravity, basket if needed
Semirigid scope
tip 6 to 8 Fr, shaft 7.5 to 10 Fr
Working length
about 33 cm (women), 43 to 45 cm (men)
Working channel
one 3.6 Fr, or two of about 2.4 and 3.4 Fr
Wires
0.035 or 0.038 inch
Laser fibre
200 to 365 micron
Rigid cystoscope
17 to 22 Fr
Owner-confirmed typical sizes for teaching: check them against the scopes on your own tray. Drawings are to relative scale within each panel, not between panels.

How to use this module. Watch the two wires: the teal safety wire goes up first, the white working wire through the scope. The card under the animation gives the scope, channel and wire sizes.

Click me next Section 2 of 8 Anatomy The structures this operation works between, and the one it must not cross.

The structures in the scene

URSL: how the structures relateRetrograde up the ureter from the bladder to the renal pelvis. Bladder and VUJ: the distal coil sits here Distal coil of the stent; safety wire first. Bladder and VUJ: narrowings where stones lodge and the scope catches Pelvic brim, iliac vessels. Pelvic brim, iliac vessels: tented on both wires, railroaded up Semirigid scope over the working wire. Pelvic brim, iliac vessels: lodged at a narrowing Impacted stone. Impacted stone: easiest place to perforate or avulse Oedematous, friable wall (danger). Impacted stone: dragging a basketed stone up avulses it Proximal ureter, thinnest wall (danger). Proximal ureter, thinnest wall: the PUJ is the narrowest proximal point Renal pelvis and PUJ.Distal: bladderProximal: kidneyBladder and VUJDistal coil ofthe stent; safetywire firstPelvic brim, iliac vesselsSemirigid scopeover the workingwireImpacted stone!Oedematous,friable wall!Proximal ureter, thinnestwallRenal pelvis and PUJthe distal coilsits herenarrowings where stones lodgeand the scope catchestented on bothwires, railroadeduplodged at a narrowingeasiest place toperforate or avulsedragging a basketed stone upavulses itthe PUJ is the narrowestproximal pointTargetDangerLandmarkContext
Retrograde up the ureter from the bladder to the renal pelvis. Schematic, not to scale; relationships only.
  • The ureteric wall is only millimetres thick and thinnest where the stone has been impacted.
  • The whole case is a negotiation between clearing the stone and respecting that wall.
  • ›Renal pelvis & PUJ - the funnel the wire reaches first; the PUJ is the narrowest proximal point.
  • ›Ureter - three physiological narrowings - PUJ, pelvic brim (iliac vessels), VUJ - where stones lodge and the scope catches.
  • ›Impacted stone - sits in oedematous, friable mucosa; the longer it has been there, the more hostile the wall.
  • ›Bladder & VUJ - the retrograde starting point; the distal coil of the stent sits here.
  • ›Two wires - the safety wire in the centre, placed first, never moves; the working wire runs through the scope and only guides it.
Click me next Section 3 of 8 Steps The operation in order, with the landmark that guards each move.

Operative steps

  1. Bladder view: cystoscopy and the safety wire A septic or obstructed system is drained first and the stone left for another day; the urine is known to be sterile or the infection treated before any scope goes up. Cystoscopy is performed and the bladder surveyed: the trigone, both orifices, the left one the target. A 0.035 inch safety wire is advanced up the orifice under fluoroscopy, its course read against each narrowing, until it curls in the renal pelvis. It is the centre wire, placed first, and it stays for the whole case, so that whatever happens to the scope, the stone or the wall, access to the upper tract is never lost. Its position is confirmed on screening before the cystoscope comes out.
  2. Second wire through the semirigid scope, tent and railroad The semirigid ureteroscope goes in with a second, working wire already through its channel and is brought to the orifice beside the safety wire. The working wire is advanced up the ureter through the scope; it exists only to guide the scope and is withdrawn once the stone is seen. With both wires held gently taut the ureter tents and straightens, and the scope is railroaded over the working wire with every level of the lumen entered under direct vision. The physiological narrowings each announce themselves as a catch and are crossed by withdrawing slightly, realigning and advancing, not by pushing. A tight orifice yields to rotating the scope through 180 degrees; a sheath rarely helps in the ureter. Never advance against resistance: that is how the wall tears.
    where it bites: never advance against resistance - that is how the wall tears.
  3. Laser: dust it, never chunk it The working wire is pulled once the stone is in view and the safety wire kept. The holmium or thulium fibre is passed down the working channel and advanced a short distance beyond the scope before firing, its tip kept visibly on the stone and off the mucosa and well clear of the lens. Irrigation is kept to a trickle so the stone is not flushed back to the kidney. The stone is dusted at low energy, face by face, painted rather than cracked. Never fragment in the ureter into large pieces: they scatter, they do not pass, and they invite the pull that avulses. Firing on the wall rather than the stone perforates within seconds.
    where it bites: firing on the wall, not the stone, perforates within seconds.
  4. Clearance: gravity first, basket if needed Dust and fine fragments are left to clear downwards by gravity and the trickle of irrigation. A fragment too big to clear on its own is taken with a nitinol basket opened beyond the scope, one piece at a time, and drawn back only after the test before any pull: the engaged piece comes to the scope tip without the basket bowing or the wall dimpling. One representative fragment goes for analysis. A fragment that resists is released and lasered smaller, never pulled. Pulling an over-large fragment in a basket is the classic route to avulsion, and it happens at the thin proximal wall where nothing can be repaired from below.
    where it bites: pulling an over-large fragment in a basket is the classic route to avulsion.
  5. Exit + selective JJ stent The scope is withdrawn under vision with the whole length of the ureter inspected on the way out for a tear, a flap or extravasation. An uncomplicated ureteroscopy needs no routine stent; one is placed over the safety wire under screening for wall injury, oedema, residual fragments, bleeding, infection, a solitary kidney or uncertain drainage. Its length is matched to the patient and the treated segment so neither coil sits under tension, the wire is withdrawn under screening as the proximal coil forms, and the position is confirmed by the distal coil seen in the bladder and the proximal coil on the screen rather than assumed. Every stent leaves theatre with a removal date written in the note and the stent register, because a forgotten stent is the complication that follows the operation home.
Click me next Section 4 of 8 Danger zones Where this operation bites, and why it bites there.
Critical relationship

Danger zones

The spatial relationships the animation is built to make automatic. Before you read each one, ask yourself: at this point in the operation, what is about to go wrong, and what is my first move? The save for each sits in the Complications tab.

  • RiskImpacted segment - oedematous, friable, and the easiest place to perforate or avulse.
  • RiskProximal ureter on withdrawal - the wall is thinnest proximally; avulsion classically happens dragging a basketed stone up through the proximal segment.
  • RiskFibre tip off-target - a few millimetres of mucosa is all that separates the lumen from extravasation.
Practise it Take me into the scene Opens the animation at a danger moment and asks you to predict the mechanism and your first move before it reveals.
Click me next Section 5 of 8 Complications The save for each one: the first move, the escalation trigger, the op-note line.

Complications and immediate saves

Trigger each of these live in the Animation tab, then read the save: the first move, the escalation trigger, and the line that goes in the op note.

Perforation / extravasation

  • irrigant tracks beyond the wall; stop, stent, image.
  • Most settle with drainage.
The save
  1. Stop. Stop advancing the scope and stop lasing the instant you suspect it. first move
  2. Keep the safety wire across the injury - do not lose access to the upper tract.
  3. A gentle retrograde contrast run confirms it: irrigant or contrast tracking beyond the lumen.
  4. Place a JJ stent across the segment over the wire; most small perforations settle with drainage alone.
  5. A large defect, free extravasation, or a wire you cannot keep across → senior help; consider nephrostomy and abandon. escalation trigger
  6. Op note: site of perforation, safety wire retained, stent size placed, planned imaging and follow-up. document

Ureteric avulsion

  • full-thickness loss of a segment - the worst URS complication; retain access and call for help early.
The save
  1. Stop all traction immediately - do not pull the scope or basket any further. first move
  2. Retain access on the safety wire; it is your only bridge to the upper tract.
  3. Call for senior / consultant help now - this is not one to manage solo. escalation trigger
  4. Temporise and protect the kidney: nephrostomy with or without a stent to drain.
  5. Definitive repair is segment-dependent: distal loss → re-implantation (psoas hitch / Boari flap); long or proximal loss → ileal ureter, autotransplantation, or nephrectomy in extremis.
  6. Op note: segment and length lost, access retained, temporising drainage, referral to a reconstructive centre. document

Impacted stone + oedema

  • friable mucosa around a chronic stone; dust gently or stent and return rather than force.
The save
  1. Stop forcing - never push the scope against resistance through an impacted segment. first move
  2. Read the field: oedematous, friable mucosa is a perforation and avulsion waiting to happen.
  3. If vision and access are safe, dust at low energy in situ; do not basket an impacted stone.
  4. If you cannot proceed safely, place a JJ stent and stage the case 1–2 weeks later through a passively dilated ureter. escalation trigger
  5. Op note: impaction and oedema, what was and was not done, stent placed, staged plan. document
Click me next Section 6 of 8 Troubleshooting When the case turns: the problem, then the next move.

Intra-operative troubleshooting

When the case turns: the problem, then the next move.

  • ActionScope will not pass - do not force; place a stent and return in 1–2 weeks to a passively dilated ureter.
  • ActionPoor vision from dust - pause lasing, increase irrigation flow, reposition the fibre tip onto the stone.
  • ActionStone migrates proximally - use an anti-retropulsion device or lower energy / higher frequency dusting settings.
  • ActionBasket impacted on a fragment - do not pull; release or laser the fragment within the basket before disengaging.
  • ActionFragment too large to pass - do not basket it out through the ureter; laser it smaller in situ until it will clear by gravity, then basket only what is left.
  • ActionSafety and working wire confused - the safety wire is the one beside the scope that never moves; the working wire is the one that comes out of the scope tip and is withdrawn at the stone.
Click me next Section 7 of 8 FRCS viva Say it out loud, then mark yourself against the model answer.

FRCS viva questions

The examiner stems this scene prepares you for. Try to answer out loud first, then reveal, and learn the discriminator, the detail that turns a pass into a strong pass.

QA guidewire will not pass an impacted mid-ureteric stone. What are your options?reveal answer
  • I would not force the wire.
  • First I would confirm position with a retrograde study and try a hydrophilic or angled guidewire under screening, with gentle torque past the stone.
  • If it will not pass, I would not proceed with rigid instrumentation against resistance.
  • My safest option is to place a JJ stent alongside the stone if I can pass a wire past it, or, if not, to obtain access for drainage and return in one to two weeks to a passively dilated ureter - which makes both wire passage and stone clearance far easier and safer.
  • If the patient is septic or obstructed, decompression (stent or nephrostomy) takes priority over stone treatment.
Strong pass

Stent, then return to a passively dilated ureter

  • Staged Stent and come back to a passively dilated ureter
  • Obstructed Obstructed or septic: decompress before you clear stone
Examiner note
Naming the staged approach - stent and return to a passively dilated ureter - and putting decompression before stone clearance in an obstructed or septic patient.
QYou see extravasation of irrigant on fluoroscopy. What has happened and what do you do?reveal answer
  • There is a ureteric perforation and irrigant is tracking beyond the lumen.
  • I would stop advancing and stop lasing immediately, and keep my safety wire across the injury so I never lose access.
  • I would confirm with a gentle retrograde contrast run, then place a JJ stent across the segment over the wire; the great majority of small perforations settle with stent drainage.
  • I would limit further irrigation.
  • If there is a large defect, free extravasation, or I cannot keep a wire across, I would stop, call for senior help, consider a nephrostomy, and abandon the procedure.
  • I would document the site, the retained access, the stent, and arrange follow-up imaging before stent removal.
Strong pass

Say all three

  • Retaining the safety wire as the first priority
  • Distinguishing the small perforation (stent, settles) from the one that needs senior help
  • Nephrostomy and abandonment
Examiner note
Retaining the safety wire as the first priority, and distinguishing the small perforation (stent, settles) from the one that needs senior help, nephrostomy and abandonment.
QHow do you counsel a patient on the risk of ureteric avulsion before URS?reveal answer
  • I would explain that ureteroscopy is generally safe but carries a small risk of injury to the ureter, the most serious being avulsion - a full-thickness tear that is rare (well under 1%) but important because it usually needs further, sometimes major, reconstructive surgery such as re-implantation or replacing the ureter, and occasionally removal of the kidney.
  • I would set it in context: I take specific steps to avoid it - a safety wire, working under vision, never forcing the scope, and dusting rather than dragging large fragments.
  • I would cover the commoner risks too (infection, bleeding, stent symptoms, the need for a second procedure) and document consent.
Strong pass

Say both

  • Quoting that avulsion is rare (<1%) but consequential
  • Naming the specific intra-operative habits that prevent it rather than just listing the risk
Examiner note
Quoting that avulsion is rare (<1%) but consequential, and naming the specific intra-operative habits that prevent it rather than just listing the risk.
QDusting versus fragmentation - justify your choice for a 1 cm proximal ureteric stone.reveal answer
  • For a 1 cm proximal ureteric stone I would favour dusting with a high-frequency, low-energy holmium or a thulium fibre laser.
  • A proximal stone is at risk of retropulsion into the kidney, and low pulse energy with anti-retropulsion settings keeps the stone in place while reducing it to passable dust, avoiding the traction on a thin proximal wall that risks avulsion.
  • Fragmentation with active basket retrieval gives a stone for analysis and a clear ureter, but pulling fragments through the proximal segment is exactly the manoeuvre that avulses.
  • So I would dust, retrieve a single representative fragment for analysis if it is safe, and stent.
  • My choice is driven by stone position, retropulsion risk, and protecting the proximal wall.
Strong pass

Linking the choice to stone position and retropulsion / avulsion risk - not just reciting "dusting is faster" - and still securing a fragment for analysis.

Click me next Section 8 of 8 Evidence The guidance each of these answers is built on.

Evidence and guidance

Two minutes

Close the lap: recall it before you leave.

Say it aloud, then reveal. Reading is not remembering.

  1. 01 The relationship Say the critical spatial relationship out loud, then reveal. reveal
    Memory frame

    Millimetres of wall, thinnest where the stone is impacted

    • Wall Only millimetres thick
    • Impaction The thinnest point
    • The case Clear the stone, respect the wall
    Why?
    The ureteric wall is only millimetres thick and thinnest where the stone has been impacted. The whole case is a negotiation between clearing the stone and respecting that wall.
  2. 02 The first move Perforation / extravasation. Your first move? reveal
    First move

    Stop: stop advancing, stop lasing

    The instant you suspect it.

    More detail
    Stop. Stop advancing the scope and stop lasing the instant you suspect it.
  3. 03 The escalation trigger Perforation / extravasation. What makes you call for help? reveal
    Escalate when

    A large defect, free extravasation, or a wire you cannot keep across

    • Senior help
    • Consider nephrostomy
    • Abandon
    More detail
    A large defect, free extravasation, or a wire you cannot keep across → senior help; consider nephrostomy and abandon.
  4. 04 The discriminator What turns a pass into a strong pass? reveal
    Strong pass

    Stent, then return to a passively dilated ureter

    • Staged Stent and come back to a passively dilated ureter
    • Obstructed Obstructed or septic: decompress before you clear stone
    Examiner note
    Naming the staged approach - stent and return to a passively dilated ureter - and putting decompression before stone clearance in an obstructed or septic patient.
  5. 05 The pitfall Where does this operation bite first? reveal
    Pitfall

    The impacted segment: oedematous and friable

    The easiest place to perforate or avulse.

    Why?
    Impacted segment: oedematous, friable, and the easiest place to perforate or avulse.

Revision practice with self-marked answers, not an assessment of clinical competence. Kept in this browser only; it does not sync between devices.