Intraductal thermal injury using a heat probe and radiofrequency ablation electrode in a swine model of biliary stenosis

Feasibility of in vivo swine models using guide wire-assisted intraductal radiofrequency ablation for benign biliary stricture

Several in vivo swine models of benign biliary stenosis (BBS) have been recently reported for preclinical studies of novel endoscopic techniques and devices. The aim of this study was to evaluate the efficacy and feasibility of large animal models of BBS by using intraductal radiofrequency ablation (RFA) assisted by guide wire. Six in vivo swine models were made by using an intraductal RFA for cauterization at 10 W, 80 °C, 90 s in the common bile duct (CBD). Endoscopic retrograde cholangiopancreatography (ERCP) was performed with cholangiography and histologic evaluation was done for the common bile duct. Blood tests were examined before, after, and at the final follow-up. Guide wire assisted RFA electrode produced BBS in all (6/6, 100%) animal models without severe complications. Fluoroscopy findings at 2 weeks after intraductal RFA in every model revealed BBS in the common bile duct. In histologic evaluations, fibrosis and chronic inflammatory changes were noted. After the procedure, ALP, GGT, and CRP were elevated and decreased after an appropriate drain. A swine model of BBS is developed by inducing intraductal thermal injury using intraductal RFA assisted by guide wire. This novel technique for inducing BBS in swine is effective and feasible.

Thermal Processes in Bile Ducts During Laparoscopic Cholecystectomy with Monopolar Instruments. Experimental Study Using Real-Time Intraluminal and Surface Thermography

Introduction. A significant rate of complications during laparoscopic cholecystectomy (LC) occurs due to thermal injury caused by monopolar electrosurgery (MES) equipment. Most of them manifest weeks and months after surgery with the common bile duct (CBD) and large duodenal papilla strictures, some in the early postoperative period with bile leaks. Objective. To study thermal processes occurring in the lumen and on the surface of the bile ducts during monopolar coagulation in a porcine model of LC. Methods. The temperature of the bile ducts was measured using instrumentation consisted of biliary stent with temperature sensors, which was inserted in the porcine CBD, signal amplifier, and current sense transformer. Surface temperature was measured with a scientific grade thermal camera. Cholecystectomy was performed using a standard "critical view of safety" (CVS) approach with 5 mm monopolar laparoscopic instruments. Results. Application of MES caused significant tissue heating. Lateral thermal spread and the rate of tissue heating depended on the duration of energy application and the initial tissue temperature. In 5 out of 6 experiments, the intraluminal temperature rose up to the critical threshold, and the exposure time ranged from 54 to 560 seconds. A sensor positioned at the papilla site was heated in all the experiments but still below the cell damage inducing threshold. The analysis of thermographic charts revealed the presence of the "current channeling" effect and the pedicle effect. Conclusion. There is a possibility of a direct and delayed thermal injury to the bile ducts during LC.

Establishment of a Swine Benign Biliary Stricture Model of Endobiliary Thermal Injury With a Diathermic Sheath

BACKGROUND

A reliable large animal model of benign biliary stricture (BBS) is essential to study endoscopic management of BBS. The aim of this study was to establish a swine BBS model of endobiliary electrothermal injury with a diathermic sheath and screen out the optimal energy dose.

MATERIALS AND METHODS

Twelve swine were equally randomized into a low (20 W), a medium (30 W), and a high (40 W)-dose group. Endobiliary electrothermal injury was applied to the common bile duct using a diathermic sheath at different energy doses for 20 seconds via endoscopic retrograde cholangiopancreatography. Cholangiographic findings and liver function were evaluated weekly after thermal injury. Two animals from each group were sacrificed at 2 weeks and the other 2 sacrificed 4 weeks after thermal injury for histopathologic evaluation.

RESULTS

BBS was established successfully in 10 of the 12 animals. Two of the 4 animals in low-dose group did not produce biliary stricture at 4 weeks; in medium-dose group, BBS was induced in both animals at 2 weeks without causing severe complications; and in high-dose group, BBS was produced in 4 animals at 2 weeks, causing perforation and abdominal abscess formation in 1 animal.

CONCLUSIONS

A safe and reproducible swine model of BBS could be established successfully by applying endobiliary electrothermal injury with a diathermic sheath at 30 W for 20 seconds.

Safety Evaluation of Paclitaxel-Eluting Biliary Metal Stent with Sodium Caprate in Porcine Biliary Tract

Background/Aims

Metallic stents designed to relieve malignant biliary obstruction are susceptible to occlusive tumor ingrowth or overgrowth. In a previous report, we described metallic stents covered with paclitaxel-incorporated membrane (MSCPM-I, II) to prevent occlusion from tumor ingrowth via antitumor effect. This new generation paclitaxeleluting biliary stent is further endowed with sodium caprate (MSCPM-III) for enhanced drug delivery. The purpose of this study is to examine the safety of its drug delivery system in the porcine biliary tract.

Methods

MSCPM-III (10% [wt/vol] paclitaxel) and covered metal stents (CMSs) were endoscopically inserted in porcine bile ducts in vivo. Histologic biliary changes, levels of paclitaxel released, and various serum analytes (albumin, alkaline phosphate, aspartate transaminase, alanine transaminase, total protein, total bilirubin, and direct bilirubin) were assessed.

Results

Based on the intensity of reactive inflammation and fibrosis, changes in porcine biliary epithelium secondary to implanted MSCPM-III were deemed acceptable (i.e., safe). Histologic features in the MSCPM-III and CMS groups did not differ significantly. In a related serum analysis, paclitaxel release from MSCPM-III stents was below the limit of detection for 28 days. Biochemical analyses were also similar for the two groups, and no evidence of hepatic or renal toxicity was found in animals receiving MSCPM-III stents.

Conclusions

In a prototypic porcine trial, this newly devised metal biliary stent incorporating both paclitaxel and sodium caprate appears to be safe in the porcine bile duct.

Experience and outcomes in living donor liver procurement using the water jet scalpel

BACKGROUND

The aim of the present study was to clarify treatment outcomes of living donor liver procurement using the water jet scalpel (WJS).

METHODS

This single-center, retrospective cohort study included 40 living donors who underwent liver procurement from January 2014 to December 2018. One living donor who underwent posterior segmentectomy was excluded. Clinical data and outcomes after surgery for 20 WJS donors and 19 Cavitron Ultrasonic Surgical Aspirator (CUSA) donors were compared.

RESULTS

Preoperative and excised graft data did not differ significantly between the WJS and CUSA groups. Operation time (P = 0.025) and parenchymal transection time (P = 0.007) were significantly shorter in the WJS group. There was no difference between the groups in terms of short-term outcomes after surgery. Multivariate analysis revealed that WJS offered significant advantages over CUSA in terms of shortening parenchymal transection time (P = 0.017).

CONCLUSION

Living donor liver procurement using WJS contributes to shortening of parenchymal transection time while maintaining the same level of safety as when using CUSA.

Percutaneous endobiliary radiofrequency ablation for refractory benign hepaticojejunostomy and biliary strictures

PURPOSE

The objective of this study was to determine the safety and efficacy of percutaneous endobiliary radiofrequency ablation (ERFA) and balloon dilation for the treatment of hepaticojejunostomy (HJ) strictures resistant to surgery and/or other interventions.

MATERIALS AND METHODS

Eighteen patients who underwent percutaneous ERFA for HJ stricture were included. There were 10 men and 8 women with a mean age of 48.3±10.8 (SD) years (range: 33-69 years). The 18 patients had a total of 29 benign HJ strictures secondary to cholecystectomy (14 patients; 78.0%), Whipple procedure (3 patients; 16.6%) or blunt abdominal trauma (1 patient; 5.4%). The different end-points were technical success, clinical success, recurrence, procedure-related mortality, and morbidity.

RESULTS

Technical and clinical success rates were 100% and 83.3%, respectively. No mortality and major procedure-related complications were observed. One patient experienced minor complication (self-limited pleural effusion). Two patients did not show favorable response to ERFA whereas 10 patients had no stricture recurrence during a mean follow-up period of 7.3 months±1.0 (SD) (range: 4-10 months).

CONCLUSION

ERFA is a safe and effective treatment for benign HJ and biliary strictures. However, more studies involving more patients with a long-term follow-up period should be made to fully determine the long-term results of ERFA.

Transmural ablation of the normal porcine common bile duct with catheter-directed irreversible electroporation is feasible and does not affect duct patency

BACKGROUND AND AIMS

The aim of this study was to evaluate the feasibility and early safety of catheter-directed irreversible electroporation (IRE) of the normal common bile duct (CBD) in swine.

METHODS

IRE (2000 V, 90 pulses, 100 μs pulse) was performed in the CBD of 6 Yorkshire pigs using a catheter electrode under endoscopic guidance. Ductal patency was assessed with immediate retrograde cholangiography and contrast-enhanced CT imaging at 1 or 7 days after treatment. Animals were killed at either 1 day (n = 4, 2 ablations/animal) or 7 days (n = 2, 1 ablation/animal) after treatment. The biliary tract was extracted en bloc and the length of the ablation along the CBD mucosa was measured. The depth of ablation was quantified using cross-sections of the treated CBD wall stained with hematoxylin and eosin. Single-sample hypothesis testing was performed to verify whether the depth of ablation in the CBD was a representative outcome of IRE treatment.

RESULTS

IRE of the CBD did not result in perforation or obstruction of the organ at 1 or 7 days after treatment. The length of ablation along the CBD mucosa was 17.27 ± 5.55 mm on day 1 samples, and transmural ablation of the CBD wall was a representative outcome of the treatment (7/8 samples, P < .05). Day 1 samples demonstrated loss of epithelium, transmural necrosis, with preservation of lumen integrity. Day 7 samples demonstrated re-epithelialization, with diffuse transmural fibrosis of the CBD wall. These findings were absent from sham tissue samples.

CONCLUSIONS

Intraluminal catheter-directed IRE is feasible and safe for full-thickness ablation of the normal porcine CBD without affecting lumen patency up to 1 week after treatment.