Patient Selection and Stents
The study was approved by our institutional review board. We retrospectively reviewed the medical records and images of 69 patients who underwent bilateral metallic stent placement using SBS or SIS techniques for the treatment of unresectable malignant hilar biliary obstructions between July 2012 and April 2019 in our department. The inclusion criteria of this study were as follows: 1. diagnosis of malignant unresectable biliary hilar obstruction based on laboratory and imaging or pathological findings; 2. no previous biliary drainage prior to admission; and 3. regular follow up. Four patients were excluded, including three who were lost to follow up and one who received external drainage in another hospital. Of the remaining 65 patients who met the inclusion criteria, 38 patients underwent stent placement using the SBS technique (SBS group) and the other 27 patients underwent stent implantation with the SIS technique (SIS group).
Two types of uncovered self-expandable metallic stents (E-Luminexx (Bard Peripheral Vascular, Tempe, AZ), Microtech (Microtech, Nanjing, China)) with diameters of 8 mm and lengths of 60 mm-100 mm were used in this study.
Prior to the procedure, the biliary hilar strictures were assessed on contrast-enhanced computed tomography (CT) and/or magnetic resonance cholangiopancreatography (MRCP). To relieve pain during the procedure, intravenous sedation with oxycodone was applied.
The procedures were carried out under fluoroscopy with or without ultrasonic guidance. After successfully puncturing the right intrahepatic bile duct with a 22G Chiba needle (Cook, Bloomington, IN), a NEFF set was inserted into the bile duct. The outer cannula of the NEFF set was kept for cholangiography to evaluate the stricture site. Then, a 0.035-inch guidewire was advanced and the outer cannula of the NEFF set was exchanged with a 5F Headhunter or Cobra catheter (Cook, Bloomington, IN) to navigate through the obstruction. After passing through the stricture and subsequently measuring its length, a 6F or 8F sheath (Terumo, Tokyo, Japan) was inserted and the guidewire was kept inside with its tip in the distal duodenum. Then, the left bile duct was punctured and the same steps were then performed on the right side. Two bare SEMSs were advanced over the two guidewires on each side and deployed in the centers of the bilateral strictures. Each end of the stent should be 1.5 to 2 cm longer than the biliary stricture. The stents were placed across the sphincter of Oddi when the lower part of the common bile duct was involved. If the stricture was only at the hilum, the stents were merely placed intrabiliary to reduce the reflux of duodenal contents and decreases the risk of cholangitis. After stenting, repeat cholangiography was performed to verify stent patency and the two puncture paths were occluded through the sheaths using gelfoam pledgets (Fig. 1).
The puncture technique was the same as that mentioned above. After successful stenting on one side, a 0.035-inch guidewire and a 5F Headhunter or Cobra catheter (Cook, Bloomington, IN) were inserted on the other side into the duodenum through the mesh of the contralateral stent at the biliary hilum. A 6F or 8F long sheath was inserted over the guidewire to dilate the mesh. Then, an uncovered SEMS was advanced and deployed across the stricture. Cholangiography was repeated to evaluate the bilateral stent patency and the two puncture paths were occluded with gelfoam pledgets (Fig. 2).
After the procedure, the patients were regularly followed up to June 2019 or until the death of the patients. The follow-up visits consisted of outpatient and telephone interviews. Outpatient interviews were performed one month after stent placement. Telephone consultations were performed at two weeks and then every three months after stenting. If obstructive jaundice recurred which was confirmed by an elevated bilirubin level and dilated bile ducts on CT, the patient was encouraged to receive stent revision or external drainage.
Technical and Clinical Assessment
Technical success was defined as successful deployment of the bilateral stents in the appropriate positions and good contrast flow through the stents into the duodenum.
The clinical outcome was evaluated in the following aspects, including the improvement of jaundice at 1 week and 1 month after the procedure, complications, stent patency period, and overall survival. A significant improvement of jaundice was defined as a decrease in serum bilirubin level of more than 20% at 1 week and more than 75% at 1 month after stent placement compared with the preoperative baseline (9, 10). The complications were divided into major and minor complications according to the reporting standards of the Society of Interventional Radiology (11). Major complications were defined as those requiring major therapy, an unplanned increase in level of care or prolonged hospitalization (> 48 h) or those causing permanent adverse sequelae or death. Other complications were regarded as minor. The stent patency period was defined as the time interval between the initial stent placement and recurrence of jaundice, the last follow-up or death of the patient without evidence of jaundice. If a patient died without recurrent jaundice, the stent patency period was considered to be the same as the duration of survival. Survival was calculated from the time of the initial stent placement to death from any cause or the last follow-up visit. Data on stent patency and survival were censored for patients who were alive at the time of writing this manuscript.
The independent t-test was used to compare continuous variables. The chi-squared test or Fisher’s exact test was used to compare categorical variables, depending on the scale level. Survival curves were calculated by the Kaplan–Meier method and compared by the log-rank test. A two-tailed P-value lower than 0.05 was considered statistically significant. All analyses were carried out using SPSS version 15.0 software (SPSS, Chicago, Illinois, USA).