Basic Operation Procedures And Standardized Protocols For Using Trocar Needles in Laparoscopic Surgery

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The use of trocar needles is the first step in establishing body cavity access for laparoscopic minimally invasive surgery, and it is also one of the most critical and highest-risk stages. Proper use of trocar needles not only ensures successful pneumoperitoneum establishment but also directly determines whether the patient sustains major vascular or hollow viscus injuries.

Preoperative Preparation and Incision Selection:​ Before using the trocar needle, confirm that the patient is under general anesthesia with endotracheal intubation, and adjust the position according to the type of surgery (e.g., supine or reverse Trendelenburg with left tilt for cholecystectomy). After routine disinfection and draping, select the umbilical region or the supra-/infra-umbilical edge as the first puncture site-here the abdominal wall is thinnest, vessels are sparse, and postoperative scarring is well concealed. Use an No. 11 scalpel or a specially designed small round knife to make a skin incision of 3–10 mm along the skin lines (depending on the trocar diameter: 5 mm for a 5 mm trocar, 10 mm for a 10 mm trocar). An incision that is too small creates excessive resistance during insertion, while one that is too large easily causes air leakage or trocar dislodgement.

Pneumoperitoneum Establishment and Closed Technique Puncture:​ In most cases, a Veress needle is first used to establish CO₂ pneumoperitoneum (pressure 12–15 mmHg). After confirming adequate pneumoperitoneum, trocar insertion begins. The surgeon holds the trocar base in the right hand, with the index or middle finger extended forward along the obturator to press against the front end, limiting the insertion depth-this is the core technique to prevent uncontrolled deep penetration and visceral injury after the trocar breaks through the peritoneum. The left hand uses towel clamps to lift the abdominal wall on both sides of the incision, stretching the fascial layer to increase the distance between the anterior and posterior walls. The trocar is held at a 90° angle perpendicular to the abdominal wall (slightly tilted toward the pelvis for obese patients). Using a combination of wrist rotation and downward pressure, advance steadily, feeling the changing tissue resistance throughout.

Perceiving the "Loss of Resistance" and Verification:​ When the trocar tip penetrates the anterior rectus sheath, there is a first "give" or loss of resistance. Continuing forward, a second, more obvious loss of resistance occurs when penetrating the peritoneum, often accompanied by gas escaping from the side port of the cannula or effortless saline infusion without backflow, indicating entry into the abdominal cavity. Immediately stop advancing, withdraw the obturator, and insert the laparoscopic camera to confirm the position-visual confirmation of omentum, intestines, or the liver surface under direct vision verifies successful puncture. Then connect the insufflation tubing to maintain intra-abdominal pressure.

Use of Auxiliary Ports:​ After confirming no adhesions at the first port, make small incisions at planned sites (McBurney's point, reverse McBurney's point, left mid-clavicular subcostal, etc.) under direct laparoscopic guidance, and rotate the auxiliary trocars into place, avoiding vessels and organs under constant camera monitoring. Ensure the spacing between operating ports exceeds 5 cm to prevent "instrument crowding."

Postoperative Removal:​ At the end of surgery, first evacuate the CO₂ from the abdominal cavity. Press the contralateral abdominal wall over the puncture site to help expel residual gas, then rotate and withdraw the trocar. Puncture sites ≥10 mm must have the fascial layer sutured to prevent incisional hernia; 5 mm sites generally only require skin suturing or adhesive bandage coverage.

Standardized use of trocar needles requires the surgeon to be familiar with abdominal wall anatomical layers and master the four essentials: "lift the abdomen-rotate and advance-perceive the breakthrough-limit depth for protection." This is a fundamental required course for minimally invasive surgeons.