Ureteroscopy and Laser Lithotripsy

Ureteroscopy with laser lithotripsy is the workhorse of modern stone surgery. Modern flexible ureteroscopes and high-power lasers give access to the entire upper urinary tract and can reliably fragment any stone composition. Stone-free rates and re-treatment depend on stone burden, location, anatomy, and the specific technique chosen.

Indications

• Ureteric stones that have not passed spontaneously or after a trial of medical expulsive therapy.
• Renal stones up to approximately 2 cm; selected larger stones with staged procedures or as part of an ECIRS approach combined with PCNL.
• Failed SWL.
• Anticoagulation or bleeding diathesis where SWL is contraindicated and PCNL carries higher risk.
• Diagnostic ureteroscopy for upper-tract urothelial carcinoma — separate technical considerations apply for biopsy and ablation.

Contraindications

Absolute

• Untreated, active urinary tract infection — defer until cleared.
• Uncorrected coagulopathy.

Relative

• Hostile distal anatomy precluding safe ureteric access (severe stricture, prior reconstruction).
• Pregnancy — ureteroscopy can be performed if necessary, but defer elective intervention.
• Very large stone burden where PCNL would be a more efficient single-stage solution.

Preoperative Workup

• Imaging — non-contrast CT KUB to define stone size, density (Hounsfield units), location, and anatomical considerations (lower pole, calyceal diverticulum).
• Urinalysis and culture — mandatory before any elective stone surgery. Treat positive culture before proceeding.
• Bloods — renal function, CBC, coagulation. Group and screen for large stone burden or anticipated difficulty.
• Antibiotic prophylaxis — a single perioperative dose for all cases (AUA: a fluoroquinolone, or a 1st/2nd-generation cephalosporin ± an aminoglycoside, or a 3rd-generation cephalosporin), tailored to local resistance patterns and the patient's recent culture history.
• Pre-stenting — not routine for elective ureteroscopy. Indicated when previous access was difficult, in pregnancy, or when there is significant obstruction with infection.
• Consent — discuss stone-free rate expectations, the possibility of staged procedures, stent placement and stent symptoms, ureteric injury and stricture, infection and sepsis, and conversion to alternative procedures.
• Anticoagulation — uniquely among stone procedures, patients can remain on aspirin, clopidogrel, or warfarin for ureteroscopy (shown to be safe) — the main reason URS/RIRS is favoured in the anticoagulated patient.
• Anaesthesia — general anaesthesia with neuromuscular paralysis is preferred for renal endoscopy: it minimises respiratory variation and lets the anaesthetist hold respiration for stone fragmentation. A laryngeal mask (spontaneous breathing) introduces uncontrolled respiratory motion that moves the stone and interferes with visualisation — general or regional anaesthesia is the better choice.
• Plan for staging — if the ureteroscope cannot be advanced to the stone, leave a stent and stage a second procedure in 10–14 days; if the ureter will not accept the scope, a stent for passive dilation with reattempt after ≥ 1 week succeeds in most.

Positioning

• Lithotomy position, with stirrups supporting the legs and buttocks at the edge of the operating table.
• Pad pressure points carefully — peroneal nerve and the lateral aspect of the lower leg.
• The C-arm fluoroscopy unit must be able to image from the kidney to the bladder; check movement and field before draping.
• Skin preparation should expose the perineum and lower abdomen for fluoroscopy.

Surgical Steps

Indications, contraindications, work-up, and positioning (above) are shared. Initial access is broadly similar, but the fragmentation strategy, patient tilt, and safe laser power differ by stone location. Throughout every pathway keep a safety wire, irrigate with warm normal saline at continuous controlled pressure (< 200 mm H₂O), and drain the bladder before starting (intermittently thereafter).

Renal Stone (Retrograde Intrarenal Surgery)

1. Cystoscopy and retrograde study. Confirm anatomy, locate the affected ureteric orifice, and perform a retrograde pyelogram — a roadmap of the collecting system and stone.
2. Place a safety guidewire to the renal pelvis under fluoroscopy — do not proceed without one. A floppy hydrophilic wire is standard (curved/straight/PTFE tips help past an impacted stone or a J-hooked ureter; backing a 5-Fr catheter up to the stone can let a wire pass). Never force a wire (it perforates or tracks submucosally), and swap a glidewire for a stiffer wire once access is achieved. Purulence → stent, send a culture, and defer.
3. Place a ureteric access sheath — a 12 × 14-Fr for most cases (an 11 × 13-Fr for smaller flexible scopes; larger sheaths only in prestented ureters). It improves vision, lowers intrarenal pressure, allows repassage, and raises stone-free rates. Never advance the sheath over the stone, keep the safety wire through or outside it, and use an Amplatz super-stiff wire if it buckles.
4. Reach and inspect the kidney. Advance the flexible ureteroscope through the sheath, traverse the UPJ gently, and systematically inspect every calyx (modern scopes reach the lower pole) to locate the stone.
5. Reposition a lower-pole stone into the upper pole with a basket — this straightens the scope (protecting it) and makes fragmentation and clearance easier.
6. Tilt the patient head-down (Trendelenburg) so fragments settle into the now-dependent upper pole and do not wash down the ureter.
7. Laser lithotripsy. Use Ho:YAG or thulium fibre laser (Ho:YAG remains the efficacious, safe default; a 200-µm fibre preserves deflection and irrigation). Start a soft stone at ~0.2 J / 50 Hz (painting/dusting) and a hard stone at the lowest setting (~0.6 J / 6 Hz), titrating up:
   • Dusting: long pulse, low energy (~0.2–0.5 J), high frequency (30–80 Hz). Dusts the stone into small fragments that pass spontaneously — better for larger renal stones.
   • Fragmentation: higher energy (0.8–1.5 J), lower frequency (6–10 Hz). Breaks the stone into basketable pieces — better for ureteric and harder stones.
   • Pop-dusting / pop-corn: medium energy at high frequency with the fibre held in the centre of the calyx — useful for residual calyceal fragments.
   • Avoid EHL as first-line — electrohydraulic lithotripsy carries the highest perforation risk, whereas the holmium laser is safe ~0.5 mm from the urothelium. Fragment to smaller than the safety-wire diameter (0.035 inch) for spontaneous passage.
8. Maintain good irrigation and drainage, and keep total laser power ≤ 20–25 W in the kidney.
9. Clear and finish — see Finishing and Stenting below.

Proximal Ureteric Stone (above the iliac vessels)

Access mirrors the renal pathway, with these differences:

1. Scope. Semirigid ureteroscopy is often impractical above the iliac vessels in men (the acute pelvic-bone angle), so use a flexible scope over the working wire — place two wires at the start (a safety wire plus a working wire, via a dual-lumen catheter, an 8/10 dilator set, or the rigid scope). In women a semirigid scope often still reaches. If the stone may have migrated distally, clear the distal ureter first.
2. Access sheath eases a high proximal stone (better irrigation, lower pressure, easy repassage) — never over the stone; a small red-rubber catheter (8–12 Fr) alongside the scope keeps the bladder drained.
3. Laser as in the renal pathway — start at the lowest setting (~0.6 J / 6 Hz) and titrate up — but in the ureter keep the power ≤ 12–15 W and the frequency ≤ 15 Hz — this preserves control and limits thermal ureteral-wall injury.
4. Clear and finish — see Finishing and Stenting below.

Distal Ureteric Stone (below the iliac vessels)

1. Semirigid ureteroscopy (maximal irrigation, visualisation, and the largest working channel) alongside the safety wire.
2. Narrow orifice → "train-track" it open with a second wire through the scope; if the ureter still resists, dilate — never over the stone (trauma or extrusion).
3. Prevent retropulsion. Deploy a stone-entrapment / anti-retropulsion device above the stone, and tilt the patient head-up (reverse Trendelenburg) so gravity keeps the stone distal and it will not retropulse up the ureter.
4. Laser — start at the lowest setting (~0.6 J / 6 Hz) and titrate up; hard distal stones do well with fragmentation (0.8–1.5 J / 6–10 Hz); as anywhere in the ureter, keep power ≤ 12–15 W and frequency ≤ 15 Hz.
5. Clear and finish — see Finishing and Stenting below.

Finishing and Stenting (all pathways)

• Basket the leading fragment first, one at a time, always under direct vision — never blind-basket (ureteral-avulsion risk); release and re-fragment a piece that is too large, and send one fragment for composition analysis.
• Re-inspect the collecting system for residual stone, and withdraw the scope and access sheath under direct vision down the whole ureter to check for injury; a completion retrograde pyelogram confirms an intact system.
• Stent decision — place a JJ stent for difficult or traumatic access, ureteric oedema or visible injury, a solitary kidney, obstructing residual fragments, or a planned staged procedure; avoid routine stenting after uncomplicated URS. Placement: over a wire under direct cystoscopic vision, or under fluoroscopy alone (malposition risk unless a tether is left; converting the tether from a loop to a single suture reduces dislodgement) — confirm a good curl in both the kidney and bladder.

Key Anatomical Landmarks

• Three classical ureteric narrowings, where stones impact: the UPJ, the crossing of the iliac vessels, and the UVJ. Each can also be the site of injury during instrumentation.
• Intramural ureter — the section from the UVJ to the bladder lumen. Dilate gently if entry is difficult; do not force the scope through.
• Renal pelvis and calyces — minor calyces drain into infundibula, then major calyces (upper, middle, lower), into the renal pelvis. Lower-pole anatomy (infundibulopelvic angle, infundibular length, infundibular width) drives the difficulty of accessing and clearing lower-pole stones.
• Brödel's avascular line — relevant for percutaneous access; less directly for ureteroscopy, but ureteroscopists working in collaboration with PCNL should know it.
• Ureteric blood supply — arises from multiple sources (renal artery, gonadal, aorta, internal iliac, vesical). The most ischaemia-vulnerable segment is the mid-ureter; over-distension by an oversized access sheath is the classic ureteroscopic ischaemic injury.

Complications

Intraoperative

• Ureteric perforation — small perforations usually heal with stent drainage (leave the stent ~4 weeks; severe injury with extravasation also needs a percutaneous nephrostomy, urinoma drainage, and antibiotics). A stone extruded completely outside the collecting system is best left in place — retrieval worsens the injury. Ureteric avulsion is a surgical emergency — place a percutaneous nephrostomy and plan delayed reconstruction.
• Bleeding — typically self-limited and managed expectantly.
• Lost stone fragments retropulsed into the renal pelvis or upper calyces.

Early postoperative

• Sepsis — particularly with infected stones; the most feared complication. Even a brief, technically clean URS in an infected system can precipitate severe sepsis.
• Renal colic from residual fragments or stent-related obstruction.
• Stent symptoms — dysuria, frequency, urgency, flank pain on voiding.
• Steinstrasse — column of stone fragments obstructing the ureter, more common after high-volume dusting.

Late

• Ureteric stricture — uncommon (around 1–3%), more common after impacted, submucosal, or perforated stones (manage a submucosal stone with laser excision and a stent). It can follow even an uncomplicated URS, and 0.4–4% are asymptomatic — image after instrumentation to exclude silent obstruction.
• Recurrent stones — driven by the underlying metabolic state, not the procedure.

Postoperative Care

• Most patients are discharged the same day or the following morning after uncomplicated URS.
• Hydration and simple analgesia; antimuscarinics for stent-related bladder symptoms.
• Discharge advice: drink generously, expect intermittent haematuria for up to a week, return for fever, severe pain, or inability to void.
• Stent removal is typically arranged for 1–2 weeks postoperatively. Stents left longer than 4–6 weeks risk encrustation, particularly with infected urine or recurrent stone disease.
• Stent duration by case — a routine intraoperative stent can come out in 5–7 days (office cystoscopy, or by the patient if a string is left); leave it 2–4 weeks after a ureteral injury or balloon dilation. Prescribe an α-blocker while a stent is in place (7–14 days) to ease stent pain and help residual fragments pass.
• Imaging follow-up at 4–12 weeks with KUB and ultrasound, or low-dose CT for higher-density residual fragments.
• Stone analysis for every stone fragment retrieved — composition guides metabolic prevention.

Tips & Pitfalls

• Safety wire from the start. It is the cheapest insurance policy in stone surgery. Do not progress without it.
• Treat infection before treating stone. A "quick" URS in infected urine can become a septic disaster.
• Match the sheath to the ureter, not the surgeon's preference. Oversized sheaths cause ureteric injury that may not be obvious intraoperatively.
• Set the laser to the stone, not the other way around. Dust for large soft stones, fragment for hard ureteric stones, and adjust as you go.
• Pre-stenting is not a routine prerequisite. A passive ureteric dilation argument does not outweigh the morbidity of stent symptoms in most patients.
• Re-inspect the upper tract at the end. Two minutes of careful look-around saves the patient a steinstrasse or missed urothelial lesion.
• Displace a lower-pole stone before lasering. Relocating it to the renal pelvis or an upper-pole calyx with a basket straightens the scope and helps residual fragments clear.
• Protect the flexible scope. Pass the laser fibre only through a straight scope, don't lase in maximal deflection, reposition a lower-pole stone before firing, and avoid high-power settings while deflected — a durability protocol roughly doubled the number of uses before damage in one series. Small-caliber digital (chip-on-tip) scopes give far better optics but are fragile and costly to repair; single-use scopes are an alternative.
• Document fluoroscopy time and operative time. Both correlate with outcomes and complications and are part of any quality registry.
• Send a stone fragment for analysis — this changes downstream metabolic prevention more than any number of 24-hour urine collections.
• For uncomplicated URS, do not routinely stent. Stent only on indication; the literature is consistent on this.