T-Tube

Anatomy and Physiology

The biliary system has the highest potential anatomical variations tracts in the body. Several classification systems have been introduced to categorize the biliary system and the anatomical variations, including Couinaud, Huang et al., Karakas et al., Choi et al., Champetier et al., and Ohkubo. [8] According to the Couinaud classification system, the most common biliary system anatomical category is type A, found in 57.8% of the general population. It would be described as following: CBD is the continuation of the common hepatic duct after the cystic duct joins it. [9] The CBD then runs medially and inferiorly until it reaches the second part of the duodenum[10]. 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

Indications of T Tube can be summarized in one concept that is to stent and drain the common bile duct after choledochotomy[11]. The most common reason for performing choledochotomy is the extraction of biliary stones[2]. Choledochotomy, stone extraction, and T Tube placement was common procedure for intractable stones before the ERCP era. Since ERCP became available and expertise was developed, it became the common and less aggressive approach to CBD stones extractions[12][4]. The number of choledochotomies became much less common and unfamiliar 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 can 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 inserted through the abdominal wall into a major hepatic duct, also by interventional radiology method. It is an external drain for bile in patients with bile duct obstruction until the underlying pathology is treated.

Equipment

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 tubes can be made of different materials like latex, silicone, red rubber, and polyvinyl chloride (PVC)[13]. PVC is very inert, causing the least tissue reaction with a 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 [13]. 

Preparation

Several factors, including hypoalbuminemia, might predict the post-operative complications with T tube implementation, e.g., T-tube sinus duodenal fistula. Therefore, improving patients' status pre-operatively would prevent the occurrence of mentioned morbidities. [7]

Technique or Treatment

In patients diagnosed with both cholelithiasis and choledocholithiasis, CBD clearance accompanied by a synchronized or consequent cholecystectomy is recommended. Two well-established safe approaches are step-wise ERCP and consequent surgery, or synchronized open or laparoscopic approaches to the CBD exploration, clearance, and cholecystectomy. Current studies have not determined significant differences among the mentioned approaches. In patients who are decided to be managed with laparoscopic cholecystectomy, the presence of choledocholithiasis and the successful removal either with cystic duct approach or with a direct choledochotomy should be documented with contrast cholangiogram intraoperatively. Both mentioned approaches demand a set of specialized instrumentation, and in case of lacking the demanding equipment, a consequent ERCP would be scheduled. Following a direct choledochotomy, the size of the CBD should be evaluated. While primary repair might be considered as acceptable management in the large CBDs, the smaller sized choledochal duct should be repaired over an appropriate size T-tube. The T-tube size ranges from 10 to 18 Fr. However, the T-tube length might be customized according to the specific length of the CBD to be implemented. The CBD condition should be checked weeks following the T-tube placement, and in unsuccessful endoscopic choledocholithiasis removal, probably due to the impacted stones, transduodenal sphincterotomy might be recommended. In complete unsuccessful cases of choledocholithiasis disimpaction, a surgical bypass method, including choledochoduodenostomy or Roux-en-Y choledochojejunostomy, would be preferred. 

Placing a T tube in the CBD following a choledochotomy is technically complex. [14]. It should be done precisely to avoid any further complications. [15] The technical concept is to implement the transverse end of the T tube inside the choledochal lumen. Initially, the transverse segment is trimmed to a shorter length of 2 to 4 cm to minimize the risk of the leak and also would be cut longitudinally to make a cutting surface with a semi-circular pattern. An additional wedge cut at the confluence point of the transverse and longitudinal segments is made. [16]

Choledochotomy site closure around the tube exit should be done cautiously to avoid any tension. A 3-0 or 4-0 absorbable suture would be used to close the site. Non-absorbable suture would potentially serve as a nidus for a couple of complications, including stone formation and infection. The closure would be continued longitudinally along with the incision and CBD. Choledochotomy direction should be designed longitudinally in the anterior aspect of the duct to avoid any vascular damage. Consequently, the T-tube would be flushed to double-check both the complete tube patency and to exclude any leakage. T-tube fixation and the abdominal wall course should be selected in the shortest pattern. [17]

Complications

Complications of T tube placement can be due to the procedure technique, the nature of the disease, or patients' reasons. T tube placement demands high skills. Optimal techniques may reduce complications. Leak around the tube, tight closure of the choledochotomy, the inclusion of the T tube in the suturing is possible technique complications.

Bile leak is the most common complication with T tube placement and the following period. This could be immediate, delayed, or after removal.

In almost 1.5% of patients with retained intrahepatic stones who had been managed with percutaneous choldocoscopy and T-tube drainage, T tube sinus tract duodenal fistula might occur. [7]

Clinical Significance

The clinical use of T tubes has been significantly decreased in the last two decades due to the availability of less invasive alternatives for removing CBD stones. Because placement and removal of T tube are technically demanding and the complication rate and complexity are high, it should not be routinely performed. Less aggressive alternatives should be considered first.

Enhancing Healthcare Team Outcomes

CBD exploration can be managed with other non-T tube options. CBD stenting or primary closure can be used in selected patients. Stenting may provide a better length of stay and hospitalization cost when appropriately and selectively used[2]. It is very important clinicians, and nurses work together to manage and maintain T-tubes.