Viva · IR system
Lymphatic Interventions Viva Questions
Oral-exam style questions and answers on lymphatic interventions for MD, DNB and super-specialty practical examinations. Each answer links back to the playbook or Library entry it was written from.
- What is the anatomical lesion treated during embolization for chyluria?
- The target is an abnormal communication between refluxing renal hilar or retroperitoneal lymphatics and the urinary collecting system, termed a renal-lymphatic, pyelolymphatic or uro-lymphatic fistula.
- How do you confirm that milky urine is truly chyluria?
- Demonstration of urinary chylomicrons is confirmatory, and urinary triglycerides provide a practical biochemical test. Phosphaturia, pyuria and lipiduria are important mimics.
- What are the two principal access strategies for fistula embolization?
- The fistula may be treated by direct interstitial puncture of an opacified lumbar lymphatic channel or node, or by selective retrograde catheterization through the thoracic duct.
- Why may a balloon be placed in the thoracic duct during interstitial embolization?
- Temporary balloon occlusion reduces reflux of NBCA into the thoracic duct and systemic venous circulation while directing the embolic toward the renal-lymphatic fistula.
- What is the correct embolization endpoint?
- The fistulous renal-directed lymphatic branch should be occluded with no further collecting-system opacification and without significant embolic migration into the thoracic duct, systemic veins or urinary tract.
- Should the thoracic duct itself be routinely embolized for chyluria?
- No. The preferred target is the renal-lymphatic fistula. A patent thoracic duct should be preserved, while a demonstrated central obstruction may require individualized balloon angioplasty or stenting rather than empirical duct embolization.
- Why can chyluria recur after technically successful treatment?
- Recurrence may result from incomplete target penetration, recruitment of collateral renal lymphatics or persistent or recurrent thoracic duct outflow obstruction.
- When is sclerotherapy performed for a lymphocele?
- It is principally used for a **recurrent or persistent lymphocele** after aspiration or catheter drainage.
- Which sclerosants are commonly used in our practice?
- Sodium tetradecyl sulfate, marketed as Setrol, and polidocanol are detergent sclerosants that may be used according to an institutional protocol.
- What is done before instilling the sclerosant?
- The lymphocele is completely aspirated and an unsafe communication with bowel, urinary tract or vessels must be excluded.
- What is the difference between thoracic duct embolization and thoracic duct disruption?
- TDE requires catheterization of the thoracic duct or causative channel followed by controlled occlusion, usually with coils and NBCA. TDD is a salvage technique after failed cannulation and uses repeated needle puncture of the cisterna chyli or major retroperitoneal lymphatics to interrupt flow.
- Why are coils used before glue in conventional TDE?
- Coils provide a scaffold, slow lymph flow and reduce the risk of cranial glue migration. Glue then occludes the duct and small tributaries that coils alone may not seal.
- Where should the duct be embolized relative to a traumatic leak?
- The target duct is occluded upstream in the direction of lymph flow, which means **caudal to the leak**. The embolic construct should cover relevant collateral inflow without reaching the venous termination.
- What is the usual access set for antegrade TDE?
- A long **21 G** Chiba-type needle is used to puncture the cisterna chyli or lumbar lymphatic, followed by a **0.018-inch** wire and a **2.4–3 Fr** microcatheter.
- Why can TDE fail in nontraumatic chylothorax?
- Nontraumatic effusion may result from duct obstruction, diffuse lymphatic disease or abnormal reflux rather than a single focal leak. A normal-appearing duct or untargeted flow disorder therefore predicts poorer response to indiscriminate duct occlusion.
- What are the important delayed complications of thoracic duct occlusion?
- Chronic diarrhea, lower-extremity edema and abdominal swelling or chylous ascites have been reported. The evidence is retrospective and causality is not certain, but these outcomes should be discussed during consent.