Authors: Ian Holmes, M.D., gastroenterologist, Providence Portland Medical Center and The Oregon Clinic – Gastroenterology East
Ajay Singhvi, M.D., gastroenterologist, Providence Portland Medical Center and The Oregon Clinic – Gastroenterology East
Endoscopic ultrasound (EUS) initially was developed as a diagnostic tool in the 1980s. In 2012, the field of therapeutic EUS expanded significantly due to the introduction of lumen apposing metal stent (LAMS) technology. This stent technology continues to be a game changer for many patients and the gastroenterologists who provide care for them.
LAMS are unique dumbbell-shaped metal stents that are deployed under EUS guidance. They enable gastroenterologists with training in interventional endoscopy to connect two lumens and create new routes for drainage, bypasses and more. Additionally, newer electrocautery-enhanced (or “hot”) devices have transformed LAMS deployment into a single-step process, simplifying these new procedures and increasing the margin of safety.
Advances in treating pancreatitis
LAMS have caused a paradigm shift in managing necrotizing pancreatitis. Walled-off pancreatic necrosis can form around four weeks after an episode of necrotizing pancreatitis, and superinfection of these necrotic cavities can be life-threatening.
In the past, infections in this type of pancreatitis required surgical necrosectomy and/or percutaneous drains with interventional radiology, both of which carry high risks of cutaneous fistula formation. Internal drainage into the stomach or duodenum was possible with endoscopy, but endoscopic drainage was associated with significant risks, due in part to the lack of ultrasound guidance to assess for vasculature and the need for multiple steps to achieve drainage of collections. Additionally, these procedures were limited by small caliber plastic stents, which often did not lead to adequate drainage and had issues with getting clogged.
Now endoscopists can use EUS to identify a safe window to access the cavity, and the 15 mm to 20 mm lumen of the LAMS can drain necrotic material rapidly. The LAMS is even wide enough for the scope to pass through, so endoscopic necrosectomy can be performed at a later date if needed. Some patients even can have this done on an outpatient basis. This technique also can be combined with percutaneous drainage to speed up resolution of the cavity. This paradigm change in the management of necrotic collections has significantly reduced the need for surgery in many situations.
Advances in treating cholecystitis and gastric bypass
Many other applications of LAMS have emerged in the last few years. In carefully selected patients with cholecystitis who are not candidates for surgery, a LAMS can be placed from the duodenum or stomach into the gallbladder to create durable drainage.
Gastric bypass patients with Roux-en-Y anatomy with biliary or pancreatic pathology can have their excluded stomach reconnected with a LAMS to enable endoscopic retrograde cholangiopancreatography (ERCP), a procedure that combines upper GI endoscopy and X-rays to treat problems of the bile and pancreatic ducts. This technique has decreased the need for double balloon-assisted ERCP, which has a low success rate, or surgically-assisted ERCP, which requires a surgical gastrostomy and often requires prolonged recovery. Endoscopic gastrojejunostomies can be done in select patients with gastric outlet obstructions using LAMS as well.
The applications for successful use of LAMS are numerous. Even more encouraging, in the pipeline are newer, smaller LAMS that may enable safer biliary drainage for patients who cannot achieve biliary drainage with traditional ERCP.
Not all patients are candidates for these new techniques, however. Current LAMS are 1 cm long, so the target lumen needs to be at least that close for the stent to deploy safely. This means that ascites or peritoneal metastases may prevent some patients from benefitting from LAMS.
Seeking additional opinions
Alternative methods should always be discussed, and multidisciplinary conversations between primary care, gastroenterology, surgery, interventional radiology and oncology are needed. Providers who have patients with any of the above conditions are encouraged to contact The Oregon Clinic Gastroenterology to find out if your patient could benefit from therapeutic EUS techniques.
For more information or to refer patients, contact:
The Oregon Clinic Gastroenterology East
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