Trocart

A trocar (or trochar) is a medical or veterinary device used in minimally invasive surgery, typically made up of an awl (which may be a metal or plastic with a pointed or tapered tip), a cannula (essentially a rigid hollow tube) and often a seal, and some trocars also include a valve mechanism to allow for insufflation. Trocars are designed for placement through the chest and abdominal walls during thoracoscopic and laparoscopic surgery, and each trocar functions as a portal for the subsequent insertion of other endoscopic instruments such as grasper, scissors, stapler, electrocautery, suction tip, etc. — hence the more commonly used colloquial jargon "port". Trocars also allow passive evacuation of excess gas or fluid from organs within the body. 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, younger brother of Pierre Corneille. Originally, doctors used trocars to relieve pressure build-up of fluids (edema) or gases (bloating). 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's invention of the Southey tube. Trocars are used in medicine to access and drain collections of fluid such as in a patient with hydrothorax or ascites. In modern times, surgical trocars are used to perform laparoscopic 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.