Biliary calculi is seen on cholangiogram done on T-tube that was previously inserted into CBD. This procedure is contraindicated if T-tube is too small (less than 12 French in size), tortous T tube in tissues, [[acute pancreatitis]], and when there is another drain that is connected to the T-tube tract.<ref name="Chapman 2018"/>
Either high osmolar contrast medium or low osmolar contrast medium can be used (with concentration of 150 mg/ml). Low density contrast medium is used to prevent obscuring of the calculus. [[ProphylacticAntibiotic antiobioticprophylaxis]] and pre-medication is given one hour before the procedure. Painkillers is given during the procedure. The subject lie down in supine position on the table. PTHC is performed if biliary drainage catheter is not in-situ. The drainage catheter is then removed over the guidewire and sheath is inserted into the ducts (7 to 8 French size). Contrast is then injected through the sheath to identify any stones or strictures. If a stricture is identified, put in biliary manipulation catheter with guidewire measuring 0.035 inches and commence balloon dilatation (with balloon sizes of 8, 10, and 12 mm). Using the balloon catheter, the stones are pushed into the duodenum. If the stones are difficult to push, Dormier basket is used to push them into the duodenum. The basket is removed and guidewire is inserted back into the sheath. The sheath is then removed and biliary drainage catheter is inserted back through the guidewire. Contrast is then injected intermittently through the drainage catheter to follow-up on the position of the stones.<ref name="Chapman 2018"/>
After the procedure, pulse and blood pressure are monitored half-hourly for six hours. The subject put on bed rest for a total of four to six hours.<ref name="Chapman 2018"/>
