Did you mean: stent, Mark Stent, Charles Stent, Star Trek: Enterprise, Peter Stent, Stent (surname)
Dictionary:
stent (stĕnt)  |
[After Charles R. Stent (1845–1901), English dentist.]
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| Oncology Encyclopedia: Stenting |
Key Terms: Endoscope, Esophagus.
Definition
Stenting is a procedure in which a cylindrical structure (stent) is placed into a hollow tubular organ to provide artificial support and maintain the patency of the opening. Although it is most often used for cardiovascular functioning, it is also utilized to manage obstructions in cancer patients.
Purpose
Stents are used in cancer patients to relieve obstructions due to:
Tumors most likely to cause obstruction requiring stent placement include esophageal cancer, bronchogenic carcinoma, pancreatic cancer, cancers of the bile duct, and occasionally colorectal carcinomas.
Precautions
Every patient should be viewed individually with special consideration given to the patient's present status. Generally, surgical procedures are for the correction of a problem; but in many cancer cases, relief of symptoms is the only therapeutic option. Since it is extremely difficult to remove or reposition these stents after they are placed, the degree of relief to be offered by its insertion should be significant. The physician and the patient should discuss all alternatives and come to a mutual decision.
Description
Endoscopic retrograde cholangiopancreatography (ERCP) is the name of the procedure utilized to place most stents for pancreatic and biliary tumors. The ERCP is a flexible endoscope, which can be directed and moved around the many bends in the upper gastrointestinal tract. The newer video endoscopes have a tiny, optically sensitive computer chip at the end which transmits electronic signals up the scope to a computer that displays an image on a large video screen. The scope has an open channel that permits other instruments to be passed through it to perform biopsies, inject solutions, or place stents. Since ERCP uses x-ray films, the procedure takes place in an x-ray area. Initially the throat is anesthetized with a spray solution and the patient is also usually mildly sedated. The endoscope is inserted into the upper esophagus and a thin tube is inserted through it to the main bile duct entering the intestinal area. Dye is injected into the bile duct and/or the pancreatic duct and x-ray films are taken. The patient usually lies on the left side and then turns onto the stomach to allow complete visualization of the ducts. The patient is able to breathe easily throughout the exam and rarely gags. Any gallstones found may be removed or if the duct has become narrowed, an incision can be made using electrocautery (electrical heat) to relieve the blockage. It is also possible to widen narrowed ducts by placing stents in these areas to keep them open. The patient is taken to recovery following the procedure, which takes 20–40 minutes.
Other endoscopes are used to place stents elsewhere in the body. For example, an esophagoscope is used to place stents in cases of esophageal cancer, a broncho-scope is used for procedures involving endobronchial obstructions, and a colonoscope is used in cases of colorectal obstructions.
Preparation
The patient is instructed not to eat or drink anything for eight hours prior to the procedure. Some physicians may request that no asprin be taken for a certain time period prior to the procedure to prevent excessive bleeding.
Aftercare
The patient may go home after the procedure or may spend one or two nights in the hospital. Antibiotics may be given especially if there has been long-standing biliary obstruction. Dietary restrictions are common after esophageal and colorectal stenting.
Risks
The most serious risk associated with the placement of a stent is the risk of perforation. If a tear is made, leakage with life-threatening infection may occur. Migration or recurrent obstruction may necessitate repeat stenting if possible. Occasionally bleeding may occur.
Normal Results
Relief of the obstruction with resumption of the ability to eat, breathe, normally clear fluids from the liver or pancreas, or allow normal passage of stool is the desired result of this procedure.
Questions to Ask the Doctor
Abnormal Results
A sudden change in the degree of pain and/or fever that persists as well as any unusual changes should be communicated immediately to a physician.
Resources
Books
Dolmath, Bart L., and Ulrich Blum, editors. Stent-Grafts: Current Clinical Practice. New York: Thieme, 2000.
Other
American Cancer Society, P.O. Box 102454, Atlanta, GA 30368-2454.
American Society of Clinical Oncology. 1900 Duke Street, Suite 200, Alexandria, VA 22314. Phone: 703-299-0150.
National Digestive Diseases Information Clearinghouse. ERCP (Endoscopic Retrograde Cholangiopancreatography).
—Linda K. Bennington, C.N.S., M.S.N.
| Dental Dictionary: stent |
1. a device used to hold a skin graft placed to maintain a body orifice, cavity, or space. An acrylic resin appliance used as a positioning guide or support. 2. an appliance that maintains tissue (for example, to maintain a skin transplant in a predetermined position).
| Veterinary Dictionary: stent |
A mold for keeping a skin graft in place, made of Stent's mass or some acrylic or dental compound; by extension, a device or mold of a suitable material used to hold a skin graft in place or to provide support for tubular structures that are being anastomosed. Also used in vascular and bile duct surgery, and repair of laryngeal, tracheal, nasal trauma and stenosis.
| Wikipedia: Stent |
In medicine, a stent is a man-made 'tube' inserted into a natural passage/conduit in the body to prevent, or counteract, a disease-induced, localized flow constriction. The term may also refer to a tube used to temporarily hold such a natural conduit open to allow access for surgery.
Contents |
The origin of the word stent remains unsettled. The verb stenting was used for centuries for the process of stiffening garments (a usage long obsolete, per the Oxford English Dictionary) and some believe this to be the origin. 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 dentist Charles Stent (1807–1885), which Esser employed to craft a form for facial reconstruction. The full account is described in the Journal of the History of Dentistry.[1] According to the author, from the use of Stent's compound as support for facial tissues grew the eventual use of stent to open various bodily structures. Worth noting though is that the first "stents" used in medical practice were initially called "Wallstents".
The most widely known stent use is in the coronary arteries with a bare-metal stent, a drug-eluting stent or occasionally a covered stent.
Coronary stents are placed during a percutaneous coronary intervention procedure, also known as an angioplasty.
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. Indwelling times of 12 months or longer are indicated to hold ureters open, which are compressed by tumors in the neighbourhood of the ureter or by tumors of the ureter itself. In many cases these tumors are inoperable and the stents are used to ensure drainage of urine through the ureter. If drainage is compromised for longer periods, the kidney can be damaged. The main complications with ureteral stents are dislocation, infection and blockage by encrustation. Recently stents with coatings (e.g. heparin) were approved to reduce infection, encrustation and therefore stent exchanges.
A urethral or Prostatic stent might be needed if a man is unable to urinate. Often this situation occurs when an enlarged prostate pushes against the urethra, blocking the flow of urine. The placement of a stent can open the obstruction, avoiding the collapse of the urethra.
Stents are used in a variety of vessels aside from the coronary arteries.
Stents may be used as a component of peripheral artery angioplasty.
A stent graft is a tubular device, which is composed of special fabric supported by a rigid structure, usually metal. The rigid structure is called a stent. An average stent on its own has no covering, and therefore is usually just a metal mesh. Although there are many types of stent, these stents are used mainly for vascular intervention.
The device is used primarily in endovascular surgery. Stent grafts are used to support weak points in arteries, such a point commonly known as an aneurysm. Stent grafts are most commonly used in the repair of an abdominal aortic aneurysm, in a procedure called an EVAR. The theory behind the procedure is that once in place inside the aorta, the stent graft acts as a false lumen for blood travel through, instead of into the aneurysm sack.
Executive function has been demonstrated to decline in patients who undergo coronary artery bypass as well as individuals who receive vascular stents. The mechanism of action for cognitive decline in bypass surgery is believed to be due to the release of tiny emboli into the blood stream that subsequently travel into the brain resulting in small strokes or ischemia. While the same degree of decline in executive function or 'IQ' occurs in vascular stenting of the coronary arteries, the mechanism of action remains unknown. This decline from pre-procedure baseline has been observed soon after surgery and as far out as six years post surgery. While the decline is minimal, it is measurable, consistent and appears to be permanent. Lifestyle modifications to treat elevated cholesterol, diabetes and hypertension offer the safest course of action in treating non-life threatening coronary artery disease.
“Novel stent design for Percutaneous aortic valve replacement” - G.V.P Kumar & L.Mathew, IFMBE Proceedings,Springerlink,4th Kuala Lumpur International Conference on Biomedical Engineering 25-28 June 2008, Pages 446-448.
“Design for Percutaneous Aortic Valve Stent” – Gideon PraveenKumar & Dr.Lazar Mathew, International Conference on Biotechnology Proceedings, VIT University, Feb 8th 2008, Pages 139-140
“New Stent Design for Percutaneous Aortic Valve Replacement” - Gideon Praveen Kumar & Lazar Mathew International Journal of Cardiovascular Revascularization Medicine , (2009) , volume 10 , issue 2 , Pages 121 – 124
“Effects of Stent Design Parameters on the Aortic Endothelium " - Gideon Praveen Kumar & Lazar Mathew IFMBE Series, !3th International Conference on Biomedical Engineering, Singapore, 3 – 6 December 2008, volume 23, Pages 1539 – 1542
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Did you mean: stent, Mark Stent, Charles Stent, Star Trek: Enterprise, Peter Stent, Stent (surname)
 | Ureteral Stenting: Normal results |
| Coronary Stenting |
| Coronary Stenting: Precautions |
Copyrights:
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 | Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2007. Published by Houghton Mifflin Company. All rights reserved. Read more |
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| Oncology Encyclopedia. Gale Encyclopedia of Cancer. Copyright © 2006 by The Gale Group, Inc. All rights reserved. Read more |
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| Dental Dictionary. Mosby's Dental Dictionary. Copyright © 2004 by Elsevier, Inc. All rights reserved. Read more |
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| Veterinary Dictionary. Saunders Comprehensive Veterinary Dictionary 3rd Edition. Copyright © 2007 by D.C. Blood, V.P. Studdert and C.C. Gay, Elsevier. All rights reserved. Read more |
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| Wikipedia. This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Stent". Read more |
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