Introduction:
An endoluminal stent is placed in the gastrointestinal tract due to a block created by an abnormal growth in the intestines. It is performed as an alternative to surgical removal of the cancerous or non-cancerous lesions in the intestine where surgery is challenging. In addition, it helps relieve the symptoms like difficulty in swallowing (dysphagia) and pain caused by the tumor. The stent is placed with a fluoroscopic or endoscopically guided method.
What Are Gastrointestinal Malignancies?
Gastrointestinal malignancies are abnormal cancerous growths in the gastrointestinal tract. The lesion tends to spread to other organs or structures. A few gastrointestinal tract malignancies are listed below:
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Esophageal Cancer: Cancerous growth in the esophagus or the food pipe. The esophagus is a long tube-like structure that passes food from the mouth to the stomach.
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Gastric Cancer: Gastric cancer is a cancerous lesion growth in the stomach.
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Colorectal Cancer: An abnormal cancerous tissue growth in the colon and the rectum. The colon and the rectum are parts of the large intestine.
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Pancreatic Cancer: A cancerous tissue growth in the pancreas. The pancreas is an organ in the abdomen region that plays a vital role in digestion and regulates blood sugar levels.
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Liver Cancer: Liver cancer is an abnormal cancerous growth in the liver.
How Does Endoluminal Stenting Help in Managing Gastrointestinal Malignancies?
A cancerous lesion causes a series of symptoms like pain and difficulty in swallowing or eating. It is because it creates a block such that the food cannot pass through the esophagus. The stent placed in the esophagus opens the food to travel down to the stomach. It creates an opening in the obstructed structure caused by the tumor.
What Is Endoluminal Stenting?
Endoluminal stenting is the placement of an artificial tube that is small enough to get placed into a lumen (a passage within a tubular structure or a tubular organ) in narrow structures in the gastrointestinal tract like the esophagus, small intestine, and large intestine. This process is called endoprosthesis. Initially, the stents are made of hard plastics. These stents sometimes result in perforation and are stiff or semi-rigid, which needs additional expansion.
However, metal stents made of stainless steel, nitinol (nickel-titanium naval ordnance laboratories), and self-expandable metal stents (SEMS) resembling a mesh were developed later.
What Are the Types of Endoluminal Stents?
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Laser Cut: The laser-cut tube is nitinol which is a mesh type that has a better positioning in a short and narrow passage like the biliary tree (a system of vessels that transfers digestive enzymes from the liver, gallbladder, and pancreas to the small intestine), bronchial tree (a respiratory functional segment that supplies air from the upper airways to the lungs), and coronary vessel (a blood vessel in the heart).
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Handwoven, Wire-Braided, or Knitted Stent: These types of stents are more flexible than laser-cut stents and have less kinking (bends and create a seal while bent) effect.
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Semi-rigid, Plastic Plastic Stent: It is semi-rigid, made of polyethylene, and used for biliary tree and pancreas obstruction. They are not used in gastrointestinal tract obstructions.
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Self-Expandable Metal Stent (SEMS): They are made of stainless steel or nitinol (nickel-titanium Naval ordnance laboratories). They are available as fully covered with a synthetic polyethylene or silicone covering, partially covered, or uncovered. They look like a funnel with flares at both ends and seal the area.
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Biodegradable: These stents are made of degradable materials like pollsters, polycarbonates, and bacterial-derived polymers. They are commonly used in coronary arteries (blood vessels supplying the heart) and benign gastrointestinal lesions.
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Drug-Eluting Stents: These are commonly used in heart diseases and malignant gastrointestinal tract tumors to prevent their ingrowth and outgrowth. They have advantageous properties like delivering the drug directly to the diseased tissue.
How Is Endoluminal Stent Placed?
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The site where the stent is to be placed needs evaluation.
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The tumor size and the narrowed portion of the structure must be reviewed before placing the stent.
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The stent is placed with the help of an endoscope and a fluoroscope.
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An endoscope is a flimsy, adjustable tube that has a camera and a light attached to one end of the tube.
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The endoscope is inserted into the mouth to access the site in the upper gastrointestinal tract. Suppose the defective area is in the lower gastrointestinal tract, like the colon or the rectum. In that case, the endoscope is inserted through the anus (the external opening through which the stools are passed out of the body). This procedure is called endoscopy.
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This procedure is also guided by a fluoroscope, where an X-ray beam is continuously projected. The images are seen live with this procedure as guidance, and the endoluminal stent is placed.
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After placing the endoscope, the stent is released with a thin and portable wire-guided method into the obstructed organ.
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The narrowed portion in the obstructed region needs dilation after inserting the guided wire.
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The narrowed part due to the lesion is dilated.
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The endoscope and the fluoroscope are also removed. A fluoroscope is not always used, but in some cases, it is used as a guide.
What Are the Indications for Endoluminal Stenting in Gastrointestinal Malignancies?
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When surgery cannot be done considering the patient's safety.
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In blockages of structures like the bile duct, colon, esophagus, or small intestine.
What Are the Complications of Endoluminal Stenting in Gastrointestinal Malignancies?
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Migration: The stent, after some time, might migrate or move away from its position. In order to avoid this, the stent should have a flare at the proximal end, the other end of the stent that is placed on the healthy part of the intestinal tract.
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Perforation: Placing a rigid and short stent in an angulated part like the colon can cause perforations due to continuous compression of the tissue. A long and more compressible stent can be placed to avoid this complication.
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Stent Occlusion: Stent occlusion or blockage can occur due to tumor overgrowth, bacterial growth, or debris build-up. It can be avoided by using huge caliber stents and large sizes that cause significant dilation.
Conclusion:
Endoluminal stents in gastrointestinal malignancies are performed when surgery is impossible and can create complications. This procedure is commonly used for malignancies in the esophagus, colorectal region, biliary tree, and pancreas. The stent placed should be compressible and long to avoid perforations. The procedure is performed with a wire guide using endoscopy and fluoroscopy. This procedure is minimally invasive and needs less hospital time. In addition, placing flared stent-like self-elastic metal stents (SEMS) and nitinol (nickel-titanium naval ordnance) creates dilation in the narrowed structures. Thus, it avoids complications and improves the patient's lifespan.
