What Is A Disposable Trocar Set? A Complete Analysis Of Structure And Working Principles

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In the field of minimally invasive surgery, the "Disposable Laparoscopic Trocar Set" (commonly known as a disposable trocar or port set) is an indispensable gateway instrument in every laparoscopic procedure. Its core mission is to establish a sealed, stable, and reusable working channel through the abdominal wall, allowing laparoscopic cameras, graspers, ultrasonic scalpels, staplers, and other surgical instruments to move in and out freely. Simultaneously, through the sealing valve, it maintains an artificial pneumoperitoneum (typically at a CO₂ pressure of 12–15 mmHg), providing the surgeon with a clear and expansive operational field of view.

A standard disposable trocar set typically consists of three core components: the obturator (puncture cone/core), the cannula (sheath tube), and the seal cap assembly (sealing system). The obturator tip comes in sharp bladed, blunt conical, or bladeless dilating types, used for initially penetrating the various layers of the abdominal wall tissue. The cannula remains inside the body as the instrument channel; its outer wall is often equipped with spiral anti-slip textures or barbs to enhance abdominal wall fixation and prevent intraoperative slippage. The seal cap assembly contains a gas-tight valve (duckbill/flapper valve) and a silicone dynamic sealing ring, allowing instruments of different diameters to be inserted and withdrawn without compromising the pneumoperitoneum. Some high-end sets also integrate an insufflation tap, which can directly connect to the insufflator to introduce or release CO₂, and can passively vent excess gas or fluid.

In terms of materials, high-quality disposable trocar sets typically use medical-grade 304/316L stainless steel for the cannula inner core or reinforcing rings, while shells and sealing components are made from medical-grade polycarbonate (PC), ABS resin, nylon, and liquid silicone, all offering excellent biocompatibility. The inner surface of the cannula undergoes electropolishing to achieve a mirror-like smoothness (Ra < 0.4 μm), greatly reducing friction resistance during instrument insertion and withdrawal. The transparent tip of the obturator often uses high-transmittance engineering plastics such as Makrolon 2458 or Lexan HP1, which are bubble-free and sink-mark-free, supporting visual puncture functionality.

Clinically, the most commonly used diameters are 5 mm (observation ports and fine instrument ports), 10/11 mm (main camera channel), and 12 mm (large staplers or specimen retrieval), with 15 mm used in a few complex procedures. Lengths mostly range between 75–150 mm and must be selected based on the patient's abdominal wall thickness (BMI). Tolerance control is strict, reaching ±0.01 mm, ensuring compatibility with various imported and domestic laparoscopic instruments.

Compared to traditional reusable metal trocars, disposable trocar sets are sterilized with ethylene oxide (EO) at the factory and are ready to use upon opening the package. This completely eliminates the hidden risk of cross-infection caused by inadequate cleaning. Moreover, each puncture tip maintains consistent sharpness, and the sealing rings retain their elasticity as if brand new, effectively reducing accidental organ damage caused by excessive force applied to a dull tip. Consequently, domestic and international Class II and III medical device registrations have incorporated disposable laparoscopic trocars into the regulatory framework of the YY/T 1710-2020 standard system.

For procurement personnel, medical students, or distributors who are new to minimally invasive surgical instruments, understanding the "trinity" structure of the disposable trocar set-the obturator is responsible for entering, the cannula stays to keep the door open, and the sealing valve maintains pressure-is the prerequisite for further mastering its clinical selection and application. Subsequent articles will provide in-depth interpretations from multiple perspectives, including clinical layout, selection comparisons, manufacturing processes, infection control value, economic analysis, and future trends.