Paramount to proper visualization of intraabdominal structures is the ability to safely introduce gas into the peritoneal cavity (pneumoperitoneum). Techniques available to accomplish this objective can generally be divided into closed and open categories. Specific choice depends on surgeon experience and preference as well as careful patient selection. The primary tools used to create pneumoperitoneum by the closed technique are the Veress needle and optical viewing trocar. The alternative “open” technique uses the Hasson trocar or hand port to provide initial access.
The Veress needle allows for rapid access into the peritoneal cavity through an incision the diameter of the needle. Its two-stage mechanism features an outer barrel with a beveled point designed to penetrate tissue (Figure 1A). The inner cannula is a spring-loaded obturator that retracts during the passage through tissue, exposing the cutting outer barrel. Once the inner cannula passes into the peritoneal cavity, the sudden decrease in resistance allows the inner cannula to spring forward, shielding the outer barrel (Figure 1B). At this point insufflation gas can be passed through the needle into the peritoneal cavity.
An optical viewing trocar is a second, less frequently used tool for creation of pneumoperitoneum by closed technique. In this technique a camera is positioned inside of a pyramidal or bladed trocar, allowing visualization of the layers of the abdominal wall as they are traversed by direct force (Figure 2). A thorough understanding of the anatomy of the abdominal wall is critical for safe application of this technique.
Significant risk of damage to underlying structures is inherent with the closed techniques. In patients who have had multiple or extensive abdominal operations, the Veress needle or optical trocar should be used with extreme caution. In these circumstances, trocar insertion through a surgically created defect in the abdominal wall is often the best technique. The “open” technique for the attainment of pneumoperitoneum will not prevent the aforementioned injuries but will, it is hoped, allow early recognition.
The Hasson trocar is a blunt instrument that can be passed directly through a 10-mm fascial defect and held in position by sutures anchored to the fascia (Figure 3). Alternatively, a skin incision and fascial defect approximately the size of the surgeon’s hand can be created to allow the insertion of a mechanical valve type apparatus creating a “hand port” (Figure 4). Position and use of the hand port are largely dependent on the surgical procedure, surgeon facility with totally laparoscopic dissection, and size of the specimen to be removed.