A trocar (or trochar) is a

medical Medicine is the science and practice of caring for a patient, managing the diagnosis, prognosis, prevention, treatment, palliation of their injury or disease, and promoting their health. Medicine encompasses a variety of health care practic ...

veterinary Veterinary medicine is the branch of medicine that deals with the prevention, management, diagnosis, and treatment of disease, disorder, and injury in animals. Along with this, it deals with animal rearing, husbandry, breeding, research on nutri ...

device that is made up of an awl (which may be a metal or plastic sharpened or non-bladed tip), a

cannula A cannula (; Latin meaning 'little reed'; plural or ) is a tube that can be inserted into the body, often for the delivery or removal of fluid or for the gathering of samples. In simple terms, a cannula can surround the inner or outer surfaces ...

(essentially a hollow tube), and a seal. Trocars are placed through the abdomen during

laparoscopic surgery Laparoscopy () is an operation performed in the abdomen or pelvis using small incisions (usually 0.5–1.5 cm) with the aid of a camera. The laparoscope aids diagnosis or therapeutic interventions with a few small cuts in the abdomen.Medl ...

. The trocar functions as a portal for the subsequent placement of other instruments, such as graspers, scissors, staplers, etc. Trocars also allow the escape of gas or fluid from organs within the body.

Etymology

The word ''trocar'', less commonly ''trochar'', comes from French ''trocart'', ''trois-quarts'' (three-fourths), from ''trois'' 'three' and ''carre'' 'side, face of an instrument', first recorded in the ''Dictionnaire des Arts et des Sciences'', 1694, by

Thomas Corneille Thomas Corneille (20 August 1625 – 8 December 1709) was a French lexicographer and dramatist. Biography Born in Rouen some nineteen years after his brother Pierre, the "great Corneille", Thomas's skill as a poet seems to have shown itself e ...

, younger brother of

Pierre Corneille Pierre Corneille (; 6 June 1606 – 1 October 1684) was a French tragedian. He is generally considered one of the three great seventeenth-century French dramatists, along with Molière and Racine. As a young man, he earned the valuable patronag ...

History

Originally, doctors used trocars to relieve pressure build-up of fluids (

edema Edema, also spelled oedema, and also known as fluid retention, dropsy, hydropsy and swelling, is the build-up of fluid in the body's Tissue (biology), tissue. Most commonly, the legs or arms are affected. Symptoms may include skin which feels t ...

) or gases (

bloating Abdominal bloating (or simply bloating) is a short-term disease that affects the gastrointestinal tract. Bloating is generally characterized by an excess buildup of gas, air or fluids in the stomach. A person may have feelings of tightness, press ...

). 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 (15 September 1835 – 8 November 1899) was an English physician and inventor of ''Southey's cannula'' or ''tube'', a type of trocar used for draining oedema of the limbs.

Applications

Medical/surgical use

Trocars are used in medicine to access and drain collections of fluid such as in a patient with

hydrothorax Hydrothorax is a type of pleural effusion in which transudate accumulates in the pleural cavity. This condition is most likely to develop secondary to congestive heart failure, following an increase in hydrostatic pressure within the lungs. More ...

ascites Ascites is the abnormal build-up of fluid in the abdomen. Technically, it is more than 25 ml of fluid in the peritoneal cavity, although volumes greater than one liter may occur. Symptoms may include increased abdominal size, increased weight, ab ...

. In modern times, surgical trocars are used to perform

laparoscopic Laparoscopy () is an operation performed in the abdomen or pelvis using small incisions (usually 0.5–1.5 cm) with the aid of a camera. The laparoscope aids diagnosis or therapeutic interventions with a few small cuts in the abdomen.Medlin ...

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, 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. Trocar insertion can lead to a perforating puncture wound of an underlying organ resulting in a

medical complication A complication in medicine, or medical complication, is an unfavorable result of a disease, health condition, or treatment. Complications may adversely affect the prognosis, or outcome, of a disease. Complications generally involve a worsening in ...

. Thus, for instance, a laparoscopic intra-abdominal trocar insertion can lead to bowel injury leading to peritonitis or injury to large blood vessels with hemorrhage.

Embalming

Trocars are also used near the end of the

embalming Embalming is the art and science of preserving human remains by treating them (in its modern form with chemicals) to forestall decomposition. This is usually done to make the deceased suitable for public or private viewing as part of the funeral ...

process to provide drainage of bodily fluids and organs after the vascular replacement of blood with embalming chemicals. Rather than a round tube being inserted, the three-sided knife of the classic trocar would split the outer skin into three "wings" which was then easily sutured closed in a less obtrusive way, a trocar button can be used in place of a suture. It is attached to a suction hose, usually attached to a

water aspirator A vacuum ejector, or simply ejector is a type of vacuum pump, which produces vacuum by means of the Venturi effect. In an ejector, a working fluid (liquid or gaseous) flows through a jet nozzle into a tube that first narrows and then expands in ...

, but an electric aspirator can also be used. 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 (anatomical) left and two inches up from the navel. After the

thoracic The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the crea ...

abdominal The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the torso. ...

, and

pelvic The pelvis (plural pelves or pelvises) is the lower part of the trunk, between the abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also called bony pelvis, or pelvic skeleton). The ...

cavities have been aspirated, the embalmer injects cavity fluid into the thoracic, abdominal and pelvic cavities, usually, using a smaller trocar attached via a hose 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, there is a small thumb hole attached to the fluid injector to control the flow of liquid. The embalmer moves the trocar in the same manner used when aspirating the cavities in order to fully and evenly distribute the chemical, it is recommended to use 1 bottle of cavity fluid for the thoracic cavity and 1 for the abdominal cavity. 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 widely used by veterinarians not only for draining hydrothorax, ascites, or for introducing instruments in laparoscopic surgery, but for acute animal-specific conditions as well. In cases of

ruminal tympany Ruminal tympany, also known as ruminal bloat, is a disease of ruminant animals, characterized by an excessive volume of gas in the rumen. Ruminal tympany may be primary, known as frothy bloat, or secondary, known as free-gas bloat. In the rumen, fo ...

in cattle, a wide-bore trocar may be passed through the skin into the

rumen The rumen, also known as a paunch, is the largest stomach compartment in ruminants and the larger part of the reticulorumen, which is the first chamber in the alimentary canal of ruminant animals. The rumen's microbial favoring environment al ...

to release trapped gas. In dogs, a similar procedure is often performed for patients presenting with

gastric dilatation volvulus Gastric dilatation volvulus (GDV), also known as gastric dilation, twisted stomach, or gastric torsion, is a medical condition that affects dogs in which the stomach becomes overstretched and rotated by excessive gas content. The word bloat is o ...

in which a wide-bore trocar is passed through the skin into the stomach to immediately decompress the stomach. Depending on the severity of clinical signs on presentation, this is often performed after pain management has been administered but prior to

general anaesthesia General anaesthesia (UK) or general anesthesia (US) is a medically induced loss of consciousness that renders the patient unarousable even with painful stimuli. This effect is achieved by administering either intravenous or inhalational general ...

. Definitive surgical treatment involves anatomical repositioning of the stomach and spleen followed by a right-sided

gastropexy Gastropexy is a surgical operation in which the stomach is sutured to the abdominal wall or the diaphragm. Gastropexys in which the stomach is sutured to the diaphragm are sometimes performed as a treatment of GERD to prevent the stomach from m ...

. Depending on the severity, partial

gastrectomy A gastrectomy is a partial or total surgical removal of the stomach. Indications Gastrectomies are performed to treat stomach cancer and perforations of the stomach wall. In severe duodenal ulcers it may be necessary to remove the lower portio ...

and/or

splenectomy A splenectomy is the surgical procedure that partially or completely removes the spleen. The spleen is an important organ in regard to immunological function due to its ability to efficiently destroy encapsulated bacteria. Therefore, removal of ...

may be indicated if the relevant tissues have necrosed due to ischemia caused by torsion/avulsion of the supplying vasculature.

In popular culture

In the movie ''Far from the Madding Crowd'' (1967) Gabriel Oak, played by Alan Bates, uses a trocar to aspirate abdominal gasses from Bathsheba Everdene's herd of sheep who had strayed into a field of

clover Clover or trefoil are common names for plants of the genus ''Trifolium'' (from Latin ''tres'' 'three' + ''folium'' 'leaf'), consisting of about 300 species of flowering plants in the legume or pea family Fabaceae originating in Europe. The genus ...

and were bloated. In the movie ''

True Lies ''True Lies'' is a 1994 American spy action comedy film written and directed by James Cameron. It stars Arnold Schwarzenegger, Jamie Lee Curtis, Tom Arnold, Art Malik, Tia Carrere, Bill Paxton, Eliza Dushku, Grant Heslov and Charlton Heston. ...

'',

Arnold Schwarzenegger Arnold Alois Schwarzenegger (born July 30, 1947) is an Austrian and American actor, film producer, businessman, retired professional bodybuilder and politician who served as the 38th governor of California between 2003 and 2011. ''Time'' ...

's character, having picked the lock on his handcuffs, uses a Patterson trocar to kill his guard prior to breaking the neck of his torturer.

Citations

General and cited references

* Janet Amundson Romich. ''An illustrated guide to veterinary medical terminology, Volume 1'' * {{Authority control Medical equipment Surgical instruments