https://en.wikipedia.org/wiki/Veress_needle

A "secured" piercing tool, but even the safety mechanism can fail at times. The Veress needle was originally designed for safety – the spring-loaded blunt core is its "insurance." However, every instrument has its usage boundaries. Understanding the mechanism of action and potential failure modes of the Veress needle in terms of safety is a mandatory course for every laparoscopic surgeon.

Safety Mechanism: How Do the Springs Protect the Patients?

As mentioned earlier, the core safety feature of the Veress needle lies in the spring-driven blunt core. This design ensures that the needle tip remains sharp only when passing through the abdominal wall and automatically becomes blunt once it enters the abdominal cavity. This mechanism effectively reduces the risk of direct cutting of the intestinal tract and major blood vessels by the needle tip. Additionally, the side hole design of the Veress needle is also crucial: the gas flows out through the side hole rather than from the tip. Even if the needle tip is pressed against the peritoneum or intestinal wall, the gas can still diffuse smoothly.

What is the Veress Needle Used For? - It is Not Only for Puncturing, but Also a Risk Assessment Tool.

Experienced doctors will use the "feel" of the Veress needle to make an initial assessment of the situation within the abdominal cavity. For instance, if there is an abnormal resistance or a lack of clear "double click sensation" during the puncture process, it may indicate that the needle tip has entered the pre-peritoneal space or encountered adhesions. At this point, the doctor will stop inflating, reposition the needle, or switch to the open method. From this perspective, the Veress needle is not only a puncture tool but also a diagnostic probing tool, helping the doctor identify abnormalities before inflation.

Common Complications and Their Prevention

Despite the presence of the spring protection, the Veress needle may still cause complications, which mainly include:

• Vascular injury: The most common type is injury to the inferior epigastric artery or major vessels in the retroperitoneum. Preventive measures include choosing the appropriate puncture site (such as the midline of the umbilicus, Palmer point), controlling the puncture angle and depth.
• Intestinal perforation: This occurs more frequently in patients with adhesions. The key to prevention lies in preoperative imaging assessment of the medical history, and in cases where necessary, directly choosing the open method.
• Preperitoneal pneumoperitoneum: In this case, the needle tip does not enter the abdominal cavity but is inflated in the preperitoneal space, making subsequent operations difficult. The preventive method is to strictly follow the drop test and initial low-pressure inflation observation.
• Gas embolism: This is extremely rare but fatal. Preventive measures include ensuring that the needle tip is not within the blood vessel (negative aspiration test), and using low-flow initial inflation.

• Verification Test: The Final Gate of the Safety Chain

• No matter how confident the doctor is, he must conduct three confirmation tests before starting to inflate:
• Suction test: No blood, no intestinal contents, and no urine were drawn back.
• Drop test: The normal saline droplet at the tip of the needle was inhaled, confirming negative pressure.
• Initial inflation pressure monitoring: The pressure should be lower than 8 mmHg; otherwise, it indicates an improper position.

Summary: What is the Veress Needle Used For?

It is a self-locking puncture tool, but this lock needs to be operated and maintained correctly to be effective. Understanding its safety principle, mastering the confirmation test, and being vigilant about any complication signals are necessary to enable the Veress needle to truly fulfill its core function of "safely establishing pneumoperitoneum."