Non-vascular Intervention: Biliary, Gastrointestinal and Genitourinary
This domain tests percutaneous biliary drainage and stenting, nephrostomy and ureteric stenting, gastrostomy and abscess drainage. Expect questions on approach, catheter choice and complication avoidance.
Core rules
- Biliary drainage: use a right mid-axillary approach through the 10th or 11th intercostal space, targeting a peripheral duct; avoid the pleura. In hilar obstruction, drain one lobe that is likely to provide adequate drainage rather than attempting complete drainage.
- Nephrostomy: puncture a posterior calyx through Brodel's line under ultrasound and fluoroscopy; opacify the collecting system before puncturing; start with a small catheter and upsize if needed.
- Gastrostomy: confirm gastric apposition to the abdominal wall; avoid the colon and liver.
- Abscess drainage: use the shortest safe route; sample for microbiology; avoid traversing bowel or pleura unless unavoidable.
Worked example
A 60-year-old with hilar cholangiocarcinoma has jaundice, bilirubin 320 µmol/L and a dilated right system. Reasoning: check coagulation and platelets; perform right-sided percutaneous transhepatic biliary drainage to decompress the larger, more accessible system; drain one lobe first rather than both. Stenting is deferred until the bilirubin falls and the patient is optimised.
Traps
Puncturing too high and causing pneumothorax; failing to opacify the collecting system; using too large a catheter initially; attempting bilateral drainage in a septic, frail patient; missing a bleeding complication after biliary intervention.