Trocar
Encyclopedia
A trocar is a medical instrument with a sharply pointed end, often three-sided, that is used inside a hollow cylinder (cannula
Cannula
A cannula or canula is a tube that can be inserted into the body, often for the delivery or removal of fluid or for the gathering of data...

) to introduce this into blood vessel
Blood vessel
The blood vessels are the part of the circulatory system that transports blood throughout the body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and...

s or body cavities. Trocars are also used to introduce ports in the abdomen
Abdomen
In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...

, such as during laparoscopic surgery
Laparoscopic surgery
Laparoscopic surgery, also called minimally invasive surgery , bandaid surgery, or keyhole surgery, is a modern surgical technique in which operations in the abdomen are performed through small incisions as opposed to the larger incisions needed in laparotomy.Keyhole surgery makes use of images...

.
Sometimes the combined trocar and introduced cannula
Cannula
A cannula or canula is a tube that can be inserted into the body, often for the delivery or removal of fluid or for the gathering of data...

 are referred to as a trocar. The trocar is often passed inside a cannula, and functions as a portal for the subsequent placement of other devices, such as a chest drain, intravenous cannula, etc.

History

Originally, doctors used trocars to relieve pressure build-up of fluids (oedema) or gasses (bloat
Bloat
Bloat is a medical condition in which the stomach becomes overstretched by excessive gas content. It is also commonly referred to as torsion, gastric torsion, and gastric dilatation-volvulus when the stomach is also twisted. The word bloat is often used as a general term to cover gas distension...

). Patents for trocars appeared early in the 19th century, although their use dated back possibly thousands of years. By the middle of the 19th century, trocar-cannulas had become sophisticated, such as Reginald Southey
Reginald Southey
Reginald Southey was an English physician. Southey's cannula, or Southey's tube, is a well-known medical instrument.-Life:...

's invention of the Southey tube.

Applications

In modern times, surgical trocars are used to perform laparoscopic ('keyhole') surgery. They are deployed as a means of introduction for cameras and laparoscopic hand instruments, such as scissors, graspers, etc., to perform surgery hitherto carried out by making a large abdominal incision ('open' surgery), something that has revolutionized patient care. Today, surgical trocars are most commonly a single patient use instrument and have graduated from the 'three point' design that gave them their name, to either a flat bladed 'dilating-tip' product, or something that is entirely blade free. This latter design offers greater patient safety due to the technique used to insert them.

Trocars are also used near the end of the embalming
Embalming
Embalming, in most modern cultures, is the art and science of temporarily preserving human remains to forestall decomposition and to make them suitable for public display at a funeral. The three goals of embalming are thus sanitization, presentation and preservation of a corpse to achieve this...

 process to provide drainage of bodily fluids and organs after the vascular replacement of blood with embalming chemicals. It is attached to a suction hose (which usually is attached to a running water source and drain known as a hydroaspirator). The process of removing gas, fluids,and semi-solids from the body cavities and hollow organs using the trocar is known as aspiration. The instrument is inserted into the body two inches to the left and two inches up from the navel. After the thoracic
Thoracic cavity
The thoracic cavity is the chamber of the human body that is protected by the thoracic wall ....

, abdominal
Abdominal cavity
The abdominal cavity is the body cavity of the human body that holds the bulk of the viscera. It is located below the thoracic cavity, and above the pelvic cavity. Its dome-shaped roof is the thoracic diaphragm , and its oblique floor is the pelvic inlet...

, and pelvic
Pelvic cavity
-External links:* * *...

 cavities have been aspirated, the embalmer injects cavity fluid into the thoracic, abdominal and pelvic cavities using a smaller trocar attached via a hose which is connected to a bottle of high index cavity fluid. The bottle is held upside down in the air so as to let gravity take the cavity fluid through the trocar and into the cavities. The embalmer moves the trocar in the same manner that he or she used when aspirating the cavities in order to fully and evenly distribute the chemical.

After cavity embalming has been finished, the puncture is commonly sealed using a small, plastic object resembling a screw, called a trocar button.

Veterinary use

Trocars are also used by veterinarians and their applications include relieving of acute cases of cow bloat. A wide-bore trocar can be passed through the skin into the stomach to remove the gas, alternatively the trocars may be inserted directly into the stomach following anaesthesia in order to reduce the chances of infection.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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