A stent is a tube that is inserted into a duct or tubular structure in the body, such as an artery, to hold it open. The procedure is called stenting. Stents can help prevent or counteract localized flow constriction and also allow access for surgery. According to RadiologyInfo.org, stenting is much less invasive than large surgical interventions, which makes it a relatively low-risk and low-cost procedure. It typically requires only local anesthesia and a small cut in the skin that does not need stitching.
Types of Stents
Vascular stents are inserted into the arteries and veins; ureteral stents into the ureter--the tube that drains urine from the kidneys into the bladder--and biliary stents into the bile ducts. Less common are tracheobronchial stents for blocked large airways, and also gastrointestinal stents, which are used to treat obstructions of different parts of the gastrointestinal tract, according to the 2003 text "Holland-Frei Cancer Medicine." Most stents are made of metal or plastic mash. Specialized stents for larger arteries--stent grafts--are made of fabric that covers a metal stent. Drug-eluting stents are coated with drugs that slowly release into the artery to prevent further blockage.
Vascular Stenting
Vascular stenting can help open clogged or narrowed arteries and veins and improve the blood flow, or treat conditions caused by the buildup of cholesterol and other fatty acids on the artery walls. The surgery is performed with angioplasty, in which a tiny balloon is temporarily inserted and inflated, opening the narrowed artery, after which a stent is left in place permanently. Stenting can help in the treatment of atherosclerosis, high blood pressure, strokes and other diseases caused by narrowing of the arteries, including coronary artery disease. Specialized endovascular stent grafts can seal an aneurysm--a weak spot in artery that can rupture--making the artery stronger and allowing the blood to pass through.
Ureteral Stenting
A ureter may become obstructed due to many conditions, including kidney stones, tumors, blood clots, or infection. According to the online Encyclopedia of Surgery, a stent can help restore the flow of urine to the bladder, and may remain in the ureter for days to weeks, or on a longer term basis, for weeks or months.
Biliary Stenting
Biliary stenting is used to treat obstructions in the bile ducts--tubes that transport bile, a liquid the liver produces for fat digestion. Conditions that can cause these obstructions include pancreatic cancer, other cancers, and also injury to the bile ducts, inflammation of the pancreas, or gallstones.
Risks and Complications
Stenting, as any other procedure where the skin is penetrated, carries a risk of infection. There is also a risk of stents moving from the desired location. RadiologyInfo.org notes. Vascular stenting can injure a blood vessel, and lead to bleeding and rarely to stroke, heart attack, and sudden cardiac death. However, the risk of death is less than 1 percent, according to "Holland-Frei Cancer Medicine," while the risk of any other serious complication is less than four per 1,000. Complications associated with ureteral stenting include coiling of the stent within the ureter, or penetration of adjacent organs, such as the bowels, gallbladder or lungs. Serious complications occur in 4 percent of patients, according to the Encyclopedia of Surgery, and the rate of serious complications with billiary stenting is 5 to 11 percent.
