Forward viewing liner echoendoscopy for therapeutic interventions

Abstract

Therapeutic endoscopic ultrasonography (EUS) procedures using the forward-viewing convex EUS (FV-EUS) have been reviewed based on the articles reported to date. The earliest reported procedure is the drainage of pancreatic pseudocysts using FV-EUS. However, the study on drainage of pancreatic pseudocysts focused on showing that drainage is possible with FV-EUS rather than leveraging its features. Subsequently, studies describing the characteristics of FV-EUS have been reported. By using FV-EUS in EUS-guided choledochoduodenostomy, double punctures in the gastrointestinal tract can be avoided. In postoperative modified anatomical cases, using the endoscopic function of FV-EUS, procedures such as bile duct drainage from anastomosis, pancreatic duct drainage from the afferent limb, and abscess drainage from the digestive tract have been reported. When a perpendicular puncture to the gastrointestinal tract is required or when there is a need to insert the endoscope deep into the gastrointestinal tract, FV-EUS is considered among the options.

Keywords: Endoscopic ultrasonography-guided biliary drainage; Endosonography; Forward-viewing endoscopic ultrasonography; Interventional endoscopic ultrasonography; Therapeutic endoscopic ultrasonography.

Fig. 1.

Difference between forward-viewing convex endoscopic ultrasonography (FV-EUS) and oblique-viewing convex EUS (OV-EUS). The difference in puncture angles between FV-EUS and OV-EUS is shown. FV-EUS allows for a vertical puncture relative to the digestive tract, whereas OV-EUS is punctured at an angle to the digestive tract.

Fig. 2.

Endoscopic ultrasonography (EUS)-guided choledochoduodenostomy. The image shows the extrahepatic bile duct being punctured using forward-viewing convex EUS. A vertical puncture relative to the digestive tract is possible, avoiding double punctures of the digestive tract.

Fig. 3.

Endoscopic ultrasonography (EUS)-guided hepaticogastrostomy. The image depicts B2 being punctured with forward-viewing convex EUS (FV-EUS) and the fistula expanded using a drill dilator. Using FV-EUS makes puncturing B2 easier and safer.

Fig. 4.

Endoscopic ultrasonography-guided hepaticojejunostomy. A case of bile duct-jejunum anastomosis stenosis after a pancreaticoduodenectomy. From the afferent limb, anastomosis is punctured to place a stent.

Fig. 5.

Endoscopic ultrasonography-guided pancreaticojejunostomy. A case of pancreatic duct-jejunum anastomosis stenosis after a pancreaticoduodenectomy. By puncturing from the anastomosis side, the risk of pancreatic juice leakage and other complications is reduced.

Fig. 6.

Endoscopic ultrasonography (EUS)-abscess drainage from the afferent limb. For draining areas such as liver abscesses on the dorsal side of the liver and intraperitoneal abscesses where percutaneous drainage is difficult, drainage using forward-viewing convex EUS is effective.