Access techniques for endoscopic surgery - types of trocars, ports and cannulae - an overview.
Trocar systems with different transperitoneal access techniques are indispensable for laparoscopic surgery. The development of laparoscopic surgery has led to the establishment of two different techniques of access to the peritoneal cavity: first, there is the closed establishment of a pneumoperitoneum by direct trocar or by means of a Veress needle puncture of the abdominal cavity; this first 'blind' step of laparoscopy can be facilitated by optical control of the penetration process. The second technique is the open trocar application, first described by Hasson. Generally, trocar systems differ with respect to their reusability and there are also differences in the perforator techniques used. Particularly in single-use trocars, 'safety' perforators are applied, in which a shield protects the cutting device. Perforators can also be blunt, or vary in their cutting characteristics, with dilatation trocars at the extreme end of the scale. The risk of potential lesions to the abdominal wall and intraperitoneal organs is crucial for the evaluation of any given trocar system. When considering both cost aspects and technical details, the reusable steel trocar with a cone-shaped perforator currently appears to be the best compromise.