THC - Transhepatic Cholangiogram and Biliary Stent.

COMMENTS?

 

 

Indications to do the test: 
The usual reason to do the THC is usually obstructive jaundice with failed or unsuccessful ERCP procedure. The patient may have an elevated serum bilirubin level and look jaundiced (yellow skin) because of the build up of bile pigments in the skin. The Patient should have an abdominal CAT scan and Abdominal ultrasound and extensive medical work-up before the THC procedure is done. The THC procedure should be ordered by a specialist such as a gastero-enterologist or general surgeon. Underlying biliary obstruction secondary to mechanical cause such as impacted stone, stricture, tumor is usually the preliminary diagnosis.

Pre-Medication and Precautions:

As with all interventional procedures, BUN, Creatinine and Coagulation profile lab studies are done before hand. Many of these patients will have abnormal coagulation because of the underlying liver disease. (The Liver is responsible for manufacturing some of the clotting factors). In the event the coagulation is defective, this can be repaired with infusion of Fresh Frozen Plasma (FFP) which contains replacement coagulation proteins. If there is more time, then the patient may be given vitamin K injections over a few days to repair the coagulation factors.

The BUN and Creatinine values give information about renal function. Since iodinated contrast material is injected into the vascular system during this procedure, it is important for the patient to have good renal function to avoid renal impairment from the iv contrast material.

Also, patients are usually pre-treated with IV antibiotics because of risk of biliary sepsis (infection).

PROCEDURE:

Patient is heavily sedated with narcotics during the procedure. Under flouroscopic observation, using sterile technique and local anesthesia with xylocaine, the interventional radiologist advances a thin caliber hollow needle into the Liver substance. A small amount of radio-iodine contrast is injected manually under flouroscopic visualization until the biliary tree is demonstrated. A small wire is then advanced through the needle into the biliary tree and a catheter advanced over the wire. Once the catheter is in place, more contrast can be injected to obtain diagnostic xray pictures of the biliary tree and the cause of the obstruction can be studied. Depending on the cause and site of obstruction, a biliary sent can then be advanced into the biliary tree which will relieve the obstruction. The obstructed bile will then either drain externally into a collection bag, or if internal stenting was successful, the bile will drain internally into the GI tract as usual.

Risks and Possible Complication:

Bleeding from liver puncture site. Bile leakage from puncture site and bile peritonitis. Infection, cholangitis, abscess, renal failure.

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Transhepatic drainage tube relieves obstructed bile tree:
 

Ultrasound below shows dilated bile ducts from obstruction
Ultrasound shows stone in the common bile duct	ERCP placed biliary stent

 
ERCP endoscopic biliary cholangio pancreatography performed by a skilled gasteroenterologist is preferrable to the transhepatic procedure and is usually attempted prior to ERCP. It is preferable because of less risk of sepsis and bleeding with the ERCP procedure.

ERCP - film after removal of the endoscope
showing normal bile ducts in the liver