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.

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

1. Cystoscopy and retrograde study. Confirm anatomy, locate the affected ureteric orifice, perform a retrograde study to define the upper tract anatomy and confirm the stone location.
2. Place a safety guidewire up to the renal pelvis under fluoroscopic guidance. A floppy-tipped hydrophilic wire is standard for initial access; switch to a stiffer wire for sheath placement.
3. Choose the scope. Semi-rigid ureteroscopy is used for distal and mid-ureteric stones; flexible ureteroscopy is used for proximal ureteric, UPJ, and renal stones. In men a rigid scope often cannot be passed above the iliac vessels (advance a flexible scope over a guidewire), whereas in women the entire ureter is usually accessible with a rigid scope — always have a flexible scope available for a proximal stone. Use normal saline as the irrigant.
4. Place a ureteric access sheath when using a flexible scope for renal stones. The sheath improves visibility, reduces intrarenal pressure, allows multiple scope passes, shortens operating time, and improves stone-free rates. Choose the smallest sheath that allows free passage — oversized sheaths cause ureteric injury.
5. Inspect the upper tract systematically before treating the stone — particularly important when there is concern for upper-tract urothelial cancer.
6. Laser lithotripsy. Use Ho:YAG or thulium fibre laser:
   • Dusting: low energy (around 0.2–0.5 J), high frequency (30–80 Hz). Pulverises 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 stone into basketable pieces. Better for ureteric stones and harder stones.
   • Pop-dusting / pop-corn: medium energy at high frequency with the laser fibre held in the centre of the calyx — useful for residual fragments in calyces.
   • Avoid EHL as first-line ureteral lithotripsy — 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) to allow spontaneous passage.
7. Basket extraction of representative fragments for stone composition analysis, and of any larger fragments that will not dust effectively. Use a tipless nitinol basket.
8. Re-inspect the upper tract at the end to confirm the absence of significant residual stone and to assess for ureteric injury.
9. Stent decision. Place a JJ stent for:
   • Difficult or traumatic access.
   • Ureteric oedema or visible injury.
   • Solitary kidney.
   • Residual fragments that may obstruct.
   • Staged procedure planned.
   • Avoid routine stenting after uncomplicated URS — it increases morbidity without clear benefit.
10. Withdraw the scope under direct vision to identify ureteric injury. Document findings.

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.
• 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.
• 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.

Key Exam Points

• Safety wire from the start — do not progress without it.
• Treat infection before treating stone — URS in infected urine risks sepsis.
• Match the ureteral access sheath to the ureter size, not surgeon preference; oversized sheaths cause ureteric injury.
• Set the laser to the stone: dust for large soft stones, fragment for hard ureteric stones.
• Pre-stenting is not a routine prerequisite; the morbidity of stent symptoms outweighs the passive dilation benefit in most patients.
• Re-inspect the upper tract at the end — saves missed steinstrasse or urothelial lesions.
• Send a stone fragment for analysis — composition drives downstream metabolic prevention.
• For uncomplicated URS, do not routinely stent; stent only on indication.
• Stents left longer than 4–6 weeks risk encrustation, especially with infected urine or recurrent stone disease.
• Imaging follow-up at 4–12 weeks with KUB and ultrasound, or low-dose CT for higher-density residual fragments.
• Document fluoroscopy time and operative time — both correlate with outcomes and complications.