Gallstone disease is one of the most common benign diseases, and laparoscopic cholecystectomy (LC) and laparoscopic common bile duct exploration (LCBDE) have become the standard surgical procedure for it.[1] Various clips (Hem-o-lok clips in our department) are used to control vessels and the cystic duct, which is a safer and more efficient way when compared with conventional surgery. However, there is still a high possibility of complications, and the common complications include bile duct injury, bile leakage, infection, gastrointestinal injury, bleeding,[2] deep venous thrombosis of the lower extremity, air embolism, subcutaneous emphysema, etc. In addition, rare complications such as postcholecystectomy clip migration (PCCM), bile duct dysfunction, and bilirubin metabolism disorders have also been reported.[3] The first case of PCCM was reported in 1978 by Walker,[4] which resulted in the formation of CBD stone. Similar cases had been reported afterwards. However, rare clip migration after LCBDE whose clips dropping into CBD or forming T-tube sinus had been reported. Thus, we report six patients whose clips are found dropping into CBD (clip-stone) (3/6) or forming T-tube sinus (T clip-sinus) (3/6) after LCBDE or LC in our department to explore the reasons of it and find a more effective and safe way ligating cystic duct and gallbladder vessels. And also we review the literature from 1997 to 2017 to introduce the characteristics and treatment outcomes of these cases. (We did not search the articles earlier than 1997 considering the technology gap between these two epochs).

The first three patients underwent LCBDE due to the gallbladder and CBD stones, and we found clips forming T-tube sinus. Patient one, female, 31-year-old, the diameter of the CBD of whom is about 1.2 cm and there are a lot of stones like fine sediments within it, was indwelled with 22#T. Cholangioscope was conducted after 4 months, and we saw a small stone whose diameter was about 8 mm. Much to our surprise, we found the clips had formed a part of the sinus. We removed the stone with the reticular basket. Reviewing the pre-operative computed tomography (CT), we could see a part of sinus was consisted of by Hem-o-lok clips [Figure 1]. During these 4 months, the patient did not have cholangioscope, she was still symptom-free.

Patient two, female, 60-year-old, the diameter of the CBD of whom is about 1.1 cm, and there are a lot of small stones within it, was indwelled with 20#T. Cholangioscope was carried out after 3 months, and we saw a small stone whose diameter was around 4 mm. We also found the clips had formed a part of the sinus. Accordingly, we removed the stone with the reticular basket. Reviewing pre-operative CT, we could see a part of sinus was made up of the Hem-o-lok clips. During the whole disease process, the patient was as well symptom-free.

Patient three, female, 83-year-old, the diameter of the CBD is about 1.0 cm, and there is about 1.2 cm stone within it, was indwelled with 20#T. Cholangioscope was implemented after 6 months and we saw two small stones whose diameter was both about 3 mm. We as well found the clips had formed a part of sinus. We removed the stones with the reticular basket. Reviewing the pre-operative CT, we could see a part of sinus was consisted of by the Hem-o-lok clips. During these 6 months, the patient was symptom-free.

Patient four, this 61-year-old woman presented with repeated episodes of jaundice and upper right quadrant abdominal pain with a history of LC for chronic cholecystitis. Laboratory indices were as follows: WBC 16300/mL and total bilirubin 2.7 mg/dL. Abdominal ultrasound indicated the diameter of the CBD of is 1.1 cm, and there is a about 2.8 cm stone within it. Roux-en-Y was performed, and a clip-stone (8 mm × 22 mm) was found in CBD.

Moreover, the following two patients underwent LCBDE due to the gallbladder and CBD stones, and we found clips dropping into CBD. Patient five, female, 72-year-old, the diameter of the CBD of whom is about 1.3 cm and there are a lot of stones ranging from 0.8 cm to 1.2 cm within it, was indwelled with 22#T. Cholangioscope was conducted after 4 months and we saw two small stones. We removed the stones with the reticular basket, and we also pulled out her T tube. However, she felt pain in her right upper quadrant as before after 1½ years. Her CT scan showed a stone about 1.3 cm in CBD. We then performed exploratory laparotomy, bile duct exploration and J tube drainage because her abdominal pain aggravated and she even appeared chills and fever. We cut the stone and saw a Hem-o-lok clip inside [Figure 2 and Video 1]. The J tube was removed under endoscope after 2 weeks, and she discharged without pain or fever.

Patient six, female, 64-year-old, the diameter of the CBD of whom is about 1.5 cm, and there are two large stones (one about 1.2 cm and the other about 1.4 cm), was indwelled with 24#T. However, she appeared symptoms including fever, jaundice, skin itching and so on after 2 months. We performed T-tube cholangiography and we found that the CBD was thickened and the thickest diameter reached 1.4 cm while the lower end of the CBD became thinner and narrowed. The digital subtraction angiography of the biliary tract revealed the narrowing of the CBD and a clip drops into CBD [Figure 3 and Video 2]. As a result, percutaneous transhepatic biliary drainage and stent implantation was performed to relieve her symptoms.

LCBDE is a relatively safe way to deal with stones in CBD. Overall, PCCM is rare. However, it is possible that the true incidence of PCCM with resultant biliary complications is underestimated.[58] In this paper, clips had migrated into the CBD or formed the T-tube sinus. Common symptoms varied from abdominal pain, obstructive jaundice to fever[58] while rare complications included acute pancreatitis, embolism of the clip and so on.[142739] The etiology of clips migrating into the CBD or forming T-tube sinus remains unclear. As for clip migration, some authors held that the clips were applied improperly so that the cystic duct remained patent due to ineffective clipping resulting in biloma with bile leakage.[233259] However, others deemed that it is inevitable in that even well-placed clips may migrate due to localised inflammatory.[23] In a nutshell, there are many factors that contribute to the migration process and the aforementioned factors include inaccurate clip placements with resultant bile duct injuries, local suppurative inflammatory processes, bile leak with resultant biloma formation, local infective processes as well as the number of clips.[37] Moreover, we found the clips near the T tube and they did not drop into CBD at first while they migrated to CBD once the T tube was removed. As for T-tube sinus, there was no related literature involved about the formation process. We speculated that the distance between the T-tube and the clips might be the main cause. A short distance between them allowed the clips to gradually from the fibrous tissue of T-tube sinus and it is because both of them are foreign matters simultaneously wrapped by fibrous capsule so that we could see the clip inside sinus through choledochoscope. The angle between the two, chronic inflammation and mechanical compression from the surrounding tissues may also prompt the clips to approach the T tube.

The diagnosis primarily relied on some non-invasive examinations, such as ultrasound, CT scan, MRCP and T-tube radiography.[45] Imaging will be required to distinguish between post-cholecystectomy primary CBD stones from PCCM-related biliary complications. Simple abdominal radiography may show abnormal positions of the metal clips.[58] In our cases, diagnosis was based on the abdominal CT scan and was further confirmed by choledochoscope. And with the development of endoscopic technology, ERCP (for clip-stone) and choledochoscope (for T clip-sinus) gradually become the preferential way to deal with clip migration because they are faster, more economic with fewer traumas and complications.[1060] Performing an adequate EST is necessary and important as it may facilitate spontaneous passage to excrete stones even if the initial ERCP extraction had failed. Surgeries will be operated to handle the difficult clip-stones or acute, serious patients.[2358] Based on our past experience, bile duct exploration and J tube (a kind of ureteral catheter) drainage (primary suture the CBD) is better than T-tube drainage when tackling a single clip-stone and avoiding the migration again. After 2 weeks, we could remove the J tube with an endoscope to prevent the patients from long-term pains in the T tube.

To prevent surgical clip migration, some put forward that the blind application of clips must be forbidden and it is better to use the minimum number of clips: (1) avoid blind application of clips to control bleeding; (2) limit the length of the residual cystic duct at 0.5 cm–1.0 cm; (3) keep clips away from T-tube as much as possible.[182358] Others deemed that absorbable clips could be used and they emphasised that synthetic, absorbable sutures or other suture materials should be used for biliary surgery to reduce inflammatory reaction.[173761]

PCCM is a rare but severe complication of LCBDE. A pre-operative understanding of bile duct anatomy, the use of the minimum number of clips and the harmonic scalpel[62] during the surgeries is necessary. Considering clip-stone or clip-sinus in the differential diagnosis of patients with biliary colics or cholangitis after LCBDE even years after surgery, the detailed medical history, and pre-operative examination are inevitable, especially for these patients who had undergone LCBDE. Moreover, we are bound to have a better understanding of the disease as time goes on.