In the world of minimally invasive surgery (MIS), the trocar needle is the "keyhole" that opens body cavities and establishes surgical channels. It consists of a sharp puncture core (obturator) and a hollow outer sheath (cannula). Its core mission is to create a precise path for endoscopes and surgical instruments to reach the surgical target with minimal trauma. From the ancient drainage tool to the key entry point of modern intelligent surgical platforms, the evolution history of the trocar needle is a history of continuous breakthroughs centered around the core goals of safety, precision, efficiency, and minimally invasive.

Historical Trace: From Discharge Tools to the Foundation of Minimally Invasive Surgery

The concept of the cannula has a long history. As early as the 1st century AD, the Roman physician Aulus Cornelius Celsus described a similar tool in his works. Its name "Trocar" comes from the French word "trois-carré" (three-sided), vividly depicting the characteristics of the early triangular-shaped puncture core. For a long time, it was mainly used for draining fluid from body cavities (such as ascites, pleural effusion). The dawn of modern minimally invasive surgery first appeared in 1901, when German doctor Georg Kelling used the cannula and cystoscope to examine the abdominal cavity of dogs, which can be regarded as the prototype of laparoscopy. However, the real turning point occurred in the 1970s and 1980s, with the development of imaging technology and cold light sources, laparoscopic surgery became widespread, and the cannula evolved from a simple puncture tool into a complex and precise channel system, becoming an indispensable part of minimally invasive surgery.

The Evolution of Design Types: From "Cutting" to "Blunt Separation" and Then to "Visualization"

Percutaneous cannulation is one of the more risky steps in laparoscopic surgery, especially the placement of the first cannula, which is often a "blind insertion." To enhance safety, the design of its tip has undergone a fundamental change:

   Cutting Trocar: This is a traditional design that uses sharp blades or pyramid-shaped tips to directly cut the tissue. Although the puncture is direct, there is a risk of damaging the large blood vessels or organs behind the peritoneum.

   Bladeless/Dilating Trocar: This is the current mainstream of safe design. Its tip is conical and bladeless, and it uses continuous rotational pressure to non-cuttingly separate the muscle and fascial fibers instead of cutting. This design significantly reduces the risk of "slippage" during puncture that leads to internal organ injury, and the resulting fascial defect is smaller, helping to reduce the incidence of postoperative incisional hernia.

   Optical Trocar: This represents the most important safety innovation in recent years. Its puncture core is made of optical-grade transparent material (such as polycarbonate) and integrates a miniature endoscope. During the puncture process, doctors can observe the separation of each layer of the abdominal wall tissue (skin, subcutaneous fat, muscle, peritoneum) in real time, achieving true "direct vision" puncture, which greatly improves the success rate and safety of the first puncture.

One-off and Reusable Game

In the early days of laparoscopic surgery, reusable sterilizable metal trocars were commonly used. Although durable, they had problems such as complex cleaning and disinfection procedures, the risk of cross-infection, and the bluntening of the tip and aging of the seals after repeated use, which led to air leakage during pneumoperitoneum. Nowadays, disposable trocars have become the absolute mainstream in the global market. They ensure "one use per person, one disposal," completely eliminating the risk of cross-infection, and guaranteeing the sharpness of the puncture core and the integrity of the sealing components each time it is used, providing standardized and predictable performance for the surgery. This transformation has also profoundly influenced manufacturers such as Manners Technology, driving them to establish large-scale, high-standard sterile consumable production lines.

The Refinement of Specifications and Functions

To meet the diverse surgical requirements, the cannula needles have developed a wide range of product offerings:

   Diameter: The range covers from 3mm and 5mm (for precise operations or pediatric surgeries) to 10mm and 12mm (for placing laparoscopes or larger instruments), and even up to 15mm or more (for specimen removal). The specifications are comprehensive.

   Function integration: Modern cannulas are not just one channel. They integrate anti-leak valves (to maintain pneumoperitoneum pressure during the insertion and removal of instruments), air intake interfaces (for connecting pneumoperitoneum machines), and sometimes even suction/rinsing channels. Some innovative products even integrate fascia closure devices with the cannula design, allowing for direct suturing of the puncture hole at the end of the surgery, simplifying the process.

   Variable diameter design: To solve the inconvenience of having to replace the cannula when changing different diameter instruments during the operation, variable diameter cannulas (such as Xpan Trocar) have emerged. They allow the use of different instruments ranging from 3mm to 12mm through a single puncture hole, reducing abdominal wall trauma and the number of incisions, and also simplifying the equipment prepared in the operating room.

From the "blind insertion" relying on touch and experience, to the safe channels established under direct vision; from simple metal tubes to intelligent portals integrating sealing, flushing, and suturing functions - the evolution history of the cannula needle is a microcosm of the concept of minimally invasive surgery. International giants such as Johnson & Johnson/Ethicon, Medtronic, and B. Braun, as well as Chinese enterprises like Manners Technology that have specialized in precision manufacturing, are continuously driving this key instrument towards a safer, more convenient, and more intelligent future.