T Tube is a draining tube placed in the common bile duct after Common Bile Duct (CBD) exploration with supra-duodenal choledochotomy. It provides external drainage of bile into a controlled route while the healing process of choledochotomy is maturing and the original pathology is resolving. T tub is named to reflect the shape of the tube used for the CBD drainage. It is not be confused with the Tracheal tube or Tympanoplasty tube.

Other options of managing CBD exploration are stenting, or primary closure in selected patients have been used[1][2]. The idea and procedure was introduced and used for decades by surgeons around the world. It was the standard of care for CBD exploration until a couple of decades ago[3][4][5]. 

The CBD is the continuation of the hepatic duct after the cystic duct joins it[6]. The CBD then runs medially and inferiorly until it reaches the second part of the duodenum[7]. T tube is usually inserted at the choledochotomy site. It is part of the closure of the choledochotomy. The chosen site of choledochotomy is the common bile duct segment between the cystic duct junction and the duodenal lateral border. This is the accessible site of surgery. Upon T tube placement and closure of the choledochotomy, the tube is passed in the shortest distance to the anterior abdominal wall, then through the abdominal to the skin surface in the right upper quadrant.

Indications of T Tube can be summarized in one concept that is to stent and drain the common bile duct after choledochotomy[8]. The most common reason for performing choledochotomy is extraction of biliary stones[1]. Choledochotomy, stone extraction and T Tube placement was common procedure for intractable stones before the ERCP era. Since ERCP became available and expertise were developed, it became the common and less aggressive approach to CBD stones extractions[9][3]. The number of choledochotomies became much less common and not familiar procedure to many surgeons trained and practiced after 2000.

Another less common reason is repairing limited injury of the CBD over a T tube. Simple closure of the CBD injury without stenting and draining is associated with a high rate of stricture and or leak. T tube placement may also be used for CBD drainage when ERCP and PTC fail to clear the CBD intraluminal non-malignant obstruction. This is a rare indication, but it is an option to relieve the obstruction and prevent further complications.

A common misconception is using the word T tube interchangeably with different tubes such as Cholecystostomy tube and PTC drain. The Cholecystostomy tube is a tube that is inserted by interventional radiology method through the abdominal wall into the gallbladder, and serves as a drain to an inflamed gallbladder in patients with acute cholecystitis who are otherwise at high risk to undergo formal cholecystectomy. On the other hand, Percutaneous Transhepatic Cholangiogram (PTC) is a drain that is inserted through the abdominal wall into a major hepatic duct, also by interventional radiology method, and serves as an external drain for bile in patients with bile duct obstruction until the underlying pathology is treated.

The special part of the equipment is the T tube itself. As the name refers, it is a special tube in the shape of T with a shorter transverse part (20 cm) that stays inside the CBD (after trimming) and a long longitudinal part (60 cm) that extends from the middle of the transverse part to an end that connects with a drainage bag. This portion extends from the CBD to outside the abdominal cavity when applied. It comes with different circumference sizes (10, 12, 14, 16, 18 Fr). T tube can be made of different materials like latex, silicone, red rubber and polyvinyl chloride (PVC)[10]. PVC is very inert causing the least tissue reaction with lack of tissue tract formation making it the least favorable material for T tube placement purposes. Silicon has many favorable physical properties, but it can disintegrate with poor handling making it not a practical option for long-term placement. Latex has the desired properties to be the most commonly used. Red rubber is an alternative if latex can not be used or is not available[10].