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

When we talk about the Veress needle, we often focus on its mechanical structure and clinical techniques, but tend to overlook a fundamental question: How should the material for manufacturing the needle be chosen? According to the data, medical stainless steel has become the mainstream due to its biocompatibility and easy sterilization properties, but this is far from the end of the story.

Currently, the majority of Veress needle tips are made of 304 or 316L austenitic stainless steel. The advantages of this material are obvious: controllable cost, mature processing, and the ability to withstand 134℃ high-temperature and high-pressure steam sterilization without deformation. However, stainless steel also has its inherent limitations. Firstly, there is a contradiction between hardness and toughness - to maintain the sharpness of the needle tip, a higher hardness is required, but this will increase brittleness and there is a risk of fracture when encountering calcified rectus sheath. Secondly, there is the issue of weight. The full-steel structure of the Veress needle feels heavy in hand, and prolonged holding can lead to fatigue in the doctor's hand.

Therefore, materials scientists began to explore alternative solutions. Titanium alloys came to the forefront. Titanium alloys have a density of only 60% that of stainless steel, yet they can provide the same or even higher strength. This enables the needle to have a larger inner diameter while maintaining the same outer diameter, thereby improving the inflation efficiency. More importantly, titanium alloys have extremely strong corrosion resistance and are non-magnetic, making them suitable for interventional operations guided by MRI. However, their high cost and processing difficulties have limited their large-scale promotion.

Another route is the application of polymer composite materials. Some experimental products attempt to use polyetheretherketone to make the main body of the needle, with only very small ceramic or stainless steel blades embedded at the tip. The PEEK material itself has excellent biocompatibility and radiation transparency, facilitating imaging positioning. At the same time, its elastic modulus is closer to human tissue, and the "impact" during puncture is more realistic, which helps doctors perceive the changes in tissue layers. However, the challenge lies in that PEEK's wear resistance is not as good as metal, and after multiple uses, burrs may appear.

It is worth noting that surface treatment technology is becoming a key means to enhance the performance of traditional stainless steel. The physical vapor deposition technology deposits a layer of diamond-like film on the needle surface, which can increase the surface hardness to a level close to that of natural diamonds, while significantly reducing the friction coefficient. The puncture resistance of the treated needle can be reduced by more than 30%, and the post-operation pain score of patients in the puncture site is significantly lower. In addition, research on antibacterial coatings is also advancing. Silver ions or chitosan coatings can kill the epidermal bacteria that may enter the abdominal cavity at the moment of puncture.

For the hospital procurement department, material selection involves a trade-off between cost and performance. Standard stainless steel needles are sufficient for 90% of standard surgeries, but for obese patients, those with severe adhesions from previous surgeries, or children and other special groups, the safety premium brought by high-performance materials is worth it. In the future, as additive manufacturing technology matures, we may see a "gradient material" needle - with an extremely hard tip, a flexible shaft, and antibacterial surface, combining all these advantages in one.