In medicine, a stent is a tube or other device placed in the body to create a passage between two hollow spaces. There are a wide variety of stents used for different purposes, from expandable coronary, vascular and billiary stents, to simple plastic stents used allow the flow of urine between kidney and bladder. Stent is also used as a verb to describe the placement of such a stent, particularly when a disease such as atherosclerosis has pathologically narrowed a body structure such as an artery.
Vascular stents are commonly placed as part of peripheral artery angioplasty. Common sites treated with peripheral artery stents include the carotid, iliac, and femoral arteries. Because of the external compression and mechanical forces subjected to these locations, flexible stent materials such as nitinol are used in a majority of peripheral stent placements.
Ureteral stents are used to ensure the patency of a ureter, which may be compromised, for example, by a kidney stone. This method is sometimes used as a temporary measure to prevent damage to a blocked kidney until a procedure to remove the stone can be performed.
Example of a uretal stent used to alleviate hydronephrosis of the kidney
In 2007 the New England Journal of Medicine published the results of a trial called COURAGE. The trial gave recommendations about the practice of stenting in PCI, a heart intervention. This study was recognized as strong evidence for the need for a field-wide change in practice.
Medical societies recommend that surgeons not perform stenting in the usual surgery of otherwise healthy individuals during percutaneous coronary intervention. A report by the Chicago Tribune also noted that the use of cardiac coronary artery stents was too high in cases where the patient was in at least stable condition and the coronary artery stent(s) was implanted on an elective basis—many times more than one is implanted in the same procedure, even in the same vessel. However, the report was careful to note that they are indisputably still a viable therapy that often produces satisfactory results for those with acute coronary artery disease, such as relief of an arterial occlusion that has caused a heart attack (myocardial infarction), or where there is a danger of a piece of the blockage detaching and traveling (a thrombosis) to occlude a vessel in the cardiopulmonary system or the brain.
The origin of the word "stent" remains unsettled. The verb form "stenting" was used for centuries to describe the process of stiffening garments (a usage long obsolete, per the Oxford English Dictionary) and some believe this to be the origin. According to the Merriam Webster Third New International Dictionary, the noun evolved from the Middle English verb stenten, shortened from extenten, meaning to stretch, which in turn came from Latin extentus, past participle of extendere, to stretch out. Others attribute the noun "stent" to Jan F. Esser, a Dutch plastic surgeon who in 1916 used the word to describe a dental impression compound invented in 1856 by the English dentistCharles Stent (1807–1885), whom Esser employed to craft a form for facial reconstruction. The full account is described in the Journal of the History of Dentistry. According to the author, from the use of Stent's compound as a support for facial tissues evolved the use of a stent to hold open various bodily structures. The first (self expanding) "stents" used in medical practice in 1986 by Ulrich Sigwart in Lausanne were initially called "Wallstents". Julio Palmaz et al. created a balloon expandable stent that is currently used.
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