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Basics of endourology: cystoscopy, ureteroscopy, PCNL and TUR
Endourology works through natural openings or a skin puncture: cystoscopy and ureteroscopy through the urethra, PCNL through a puncture in the back into a posterior calyx, and transurethral resection (TURP, TURBT) — and each procedure carries typical risks that the exam tests.
Why it matters in the exam
In the PCNL puncture the posterior calyx is entered through the tip of the papilla (the fornix) and not through the infundibulum, to avoid the interlobar arteries; the posterolateral plane of the kidney (Brödel line) is relatively poor in vessels. An access above the 12th rib, and especially above the 11th rib, raises the risk of pleural injury with effusion or pneumothorax. A colon lying behind the kidney (more common in thin bodies and on the left) may be injured. After PCNL a nephrostomy, a JJ stent or no drainage (tubeless) in a simple case can be used.
In flexible ureteroscopy a ureteral access sheath is sometimes used, which lowers intrarenal pressure and eases fragment removal, but may injure the ureteral wall. Lithotripsy is done with a holmium or thulium laser. A JJ stent causes symptoms — urgency, frequency, pain on voiding and haematuria — which an alpha-blocker relieves; a "forgotten" stent becomes encrusted with stone and may need several procedures to remove. In monopolar TURP irrigation is with non-conducting glycine, and heavy absorption causes TUR syndrome with hyponatraemia; with the bipolar technique irrigation is with saline and this risk almost disappears.
Infection prevention: before any urinary tract procedure a urine culture is needed, and bacteriuria is treated. In diagnostic office cystoscopy with sterile urine no prophylactic antibiotic is needed; in ureteroscopy and PCNL a prophylactic dose is given. Elective ureteroscopy with a sterile urine culture is classed as a "clean-contaminated" operation, because the urinary tract is entered under controlled conditions. In prolonged lithotomy position there is a risk of peroneal nerve injury (foot drop) from pressure on the fibular head and of compartment syndrome.
Key points
- PCNL — posterior calyx through the papilla.
- Above the 12th rib — pleural risk.
- JJ stent — symptoms and alpha-blocker.
- Monopolar TURP — TUR syndrome.
- Urine culture before every procedure.
Summary table
| Procedure | Typical risk | Prevention or treatment |
|---|---|---|
| PCNL | Bleeding, pleural or bowel injury | Puncture through the fornix into a posterior calyx; care above the 12th rib |
| Ureteroscopy | Ureteral injury, infection | Careful use of the access sheath, culture before the procedure |
| JJ stent | Symptoms, forgotten stent | Alpha-blocker; registry and removal date |
| Monopolar TURP | TUR syndrome with hyponatraemia | Bipolar technique with saline |
| Prolonged lithotomy | Peroneal nerve, compartment syndrome | Padding and time limits |
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Sources
- EAU Guidelines on Urolithiasis, 2025 edition — Technical aspects of ureteroscopy and PCNL
- EAU Guidelines on Urological Infections, 2025 edition — Peri-procedural antibiotic prophylaxis
- Campbell-Walsh-Wein Urology, 12th edition (2020) — Ureteroscopy and Retrograde Ureteral Access; Percutaneous Management of the Upper Urinary Tract
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.