Even the most excellent cannula needle, if used improperly, can also lead to disastrous consequences. Therefore, for surgeons, mastering the correct selection principles and operational skills is of vital importance. This article will, from the perspective of clinical practice, analyze the key points of using cannula needles and the common misunderstandings.

I. How to Select the Appropriate Catheter Needle?

Select the diameter based on the type of surgery:

5mm cannula: Suitable for most basic instruments such as forceps, scissors, and electrocautery hooks.

10-12mm cannula: Used for surgeries requiring larger instruments, such as linear cutting staplers and specimen retrieval bags.

15mm and above: For hand-assisted laparoscopy or special large instruments, carefully assess the risk of incision hernia.

Select the length based on the patient's body type:

Standard length (10-15cm): Suitable for the majority of adults.

Extended length (15-20cm): For obese patients or deep operations (such as pelvic surgery).

Short length (5-8cm): For children or superficial arthroscopic surgeries.

Select the tip type based on the puncture site:

Pyramid-shaped tip: Uniform puncture force, suitable for the first puncture (the first cannula).

Blade-shaped tip: Sharp cutting edge, suitable for secondary punctures with existing incisions, but be cautious to avoid injuring internal organs.

Blunt/expandable type: Used for channel expansion after pre-puncture, with the highest safety.

Select the protection level based on safety requirements:

Routine surgery: Can choose the spring protection cover type.

High-risk patients (such as those with a history of abdominal surgery or intestinal adhesions): Strongly recommend optical visual cannula or blunt expansion technique.

II. Standardized Operating Procedures (Taking Laparoscopy as an Example)

• Preoperative preparation: Ensure that the pneumoperitoneum machine, light source, and camera system are functioning properly. Check the integrity of all components of the cannula needle, especially the sealing valve, to ensure it is flexible.
• Incision selection: Usually, the umbilicus or the surrounding area of the umbilicus is chosen as the first puncture point. The incision size should be slightly smaller than the outer diameter of the cannula needle to form a tight seal.
• Establishing pneumoperitoneum: First, inflate with a Veress needle, and when the pressure reaches 12-15 mmHg, proceed with the puncture. Alternatively, an open method (Hasson method) can be used to directly cut through the peritoneum and insert the cannula needle under direct vision.
• Puncture technique:
• Grasp the handle of the cannula needle, apply force with the wrist rather than the arm.
• The puncture direction should be towards the pelvis or the target area, avoiding major blood vessels such as the aorta and iliac arteries.
• Feel two "air loss sensations": the first is after penetrating the sheath of the rectus abdominis muscle, and the second is after penetrating the peritoneum.
• Once the peritoneum is broken, immediately stop advancing, withdraw the puncture core, and hearing the sound of gas escaping indicates success.
• Fixation and sealing: Tighten the fixing nut on the outer cannula or inflate the airbag to prevent slippage. Connect the pneumoperitoneum tube and check for any leaks.

III. Common Misunderstandings and Prevention Measures

• Misconception 1: Excessive force. Excessive force during puncture may cause a sudden rupture and injury to the posterior organs. The correct approach is to apply force at a constant speed and within control.
• Misconception 2: Ignoring the angle. The cannula needle should be perpendicular to or slightly inclined to the abdominal wall. Excessive inclination will increase the puncture distance and the risk of injury.
• Misconception 3: Reusing disposable products. Many plastic cannula needles are for single use. Repeated disinfection will reduce the material strength and air tightness, increasing the risk of fracture and infection.
• Misconception 4: Not checking the sealing valve. A failed sealing valve will make it difficult to maintain pneumoperitoneum and affect the surgical field. Before each use, manually press the valve to test its rebound.
• Misconception 5: Improper tube removal. At the end of the surgery, the cannula needle should be slowly removed under direct vision, and the puncture point should be checked for active bleeding. For incisions larger than 10mm, the fascial layer should be sutured to prevent incision hernia.

IV. Identification and Management of Complications

• Bleeding at the puncture site: This is mostly caused by abdominal wall vessel injury. It can be stopped by applying pressure or suturing. In severe cases, conversion to open surgery is necessary.
• Internal organ injury: Such as intestinal perforation or bladder perforation. Once discovered, it should be immediately repaired, and antibiotics should be considered for infection prevention.
• Incisional hernia: This is common in patients with puncture sites larger than 10mm that have not been sutured with fascia. It presents as a reducible mass several months after the operation and requires surgical repair.

Summary

The correct use of the cannula needle is the first step towards the success of minimally invasive surgery. Doctors not only need to be familiar with the characteristics of different products, but also must master the standardized operation procedures and remain vigilant about potential risks. Only by combining the "human factor" with the "advantages of the equipment" can the core value of the cannula needle in minimally invasive surgery be truly exerted, bringing the patients the least trauma and the best prognosis.