How are medical plastics a true alternative to metal medical components?
Improved material engineering has resulted in improved polymers, and modern high-performance polymers are doing things that were once thought impossible for plastic. The term “plastic” doesn’t adequately explain what high-performance polymers are. Just as there is a performance gap between certain metals, like titanium and mercury, there are also performance differences between PEEK or Torlon, and polystyrene.
High-performance medical plastics provide an impressive set of physical properties, and those in the medical field have taken notice. The ongoing debate in many medical disciplines is whether metal or high-performance plastics are the best choice for fabricating medical components. The debate isn’t settled, but polymers have some decisive advantages here. As such, they are replacing metal in many applications.
Why are medical plastics an attractive option for medical professionals?
High-performance polymers are quickly gaining traction in multiple medical disciplines, including orthopedics, dentistry, cardiovascular and arthroscopy, among others. Additional uses for high-performance medical polymers are being developed all the time, so the material will find its way into more medical devices as time goes on. But what is driving this shift from metal to plastic?
- Cost – Hospitals are constantly battling the spread of infection. This is true even at world class facilities, as Houston Methodist, in 2009, experienced an infection outbreak that harmed seven people before it was contained. The cause of the infection was narrowed down to one of two instruments, including a metal cannula that was not properly cleaned before use. Instances like these are driving hospitals to consider single-use, disposable instruments instead. Single-use instruments curb the chances of infection, so medical facilities are transitioning to them when possible. But single-use instruments can drive costs up, as they have to be replaced after each use. This is where the polymer advantage is felt, as mass producing plastic instruments is usually less expensive than producing an identical number of metal instruments. In many cases, the cost difference is significant, as single-use metal instruments aren’t practical. In some situations, high-performance polymers may provide a more cost-effective option without sacrificing the durability and material stability that metal is known for. This cost advantage goes well beyond single-use instruments, too. Using injection molding, millions of identical plastic components can be produced at a fraction of the cost of metal fabrication. This allows for the economic production of frequently needed components.
- Comfort – Plastics, including high-performance polymers, are much lighter than their metal counterparts. In some cases, this can be a difference of 80 percent. The lightweight nature of plastics has beneficial implications for both medical professionals and their patients. When used in medical devices, the lower weight allows for additional comfort. This is particularly noticeable in dental and orthopedic applications, where frequent manipulation of joints or surfaces containing the plastic components is necessary. As many dental and orthopedic patients are older or lack mobility, this weight reduction is a significant benefit. For medical professionals, lighter surgical instruments can make a difference during a procedure. It may not sound like a small difference in weight would mean much during a single procedure, but consider that some surgeries last several hours. During this time, frequent lifting and manipulation of metal instruments will produce fatigue. Plastic instruments are less likely to do so. Further, plastic components can easily be fabricated into ergonomic designs. A good example of this is an instrument used for applying torque. These instruments are frequently needed in orthopedic surgeries, where they are used to access areas prior to inserting screws or implants. Once made from stainless steel, now they are almost always fabricated from plastic. This is because a plastic torque-applying tool is easier to handle and easier to grip, both of which reduce strain on the user.
- Versatility – Metal is durable and resilient, but it is a challenge to form into complex shapes and scale up or down. High-performance medical plastics can be designed into nearly any shape imaginable, without any loss of performance. Once a mold is created, large production runs of extremely complex components can be created at reasonable costs. Improving fabrication methods have opened up many opportunities for medical plastics, and they have replaced metal in many instances, mostly to reduce cost and weight. For example, plastic is now used in many electronic medical devices, primarily as housing. Because plastics can be easily fabricated to any size, they can be readily adapted for most electronic medical instrumentation. Though this approach will save money and reduce weight, high-performance plastics also offer excellent impact resistance, thermal resistance and design features like rounded edges for easier cleaning. Polymers can also be molded with color, so hospitals can color code their instruments as they see fit.
Medical plastics are at the forefront of material engineering in the medical field. They are constantly being improved upon, but are already a perfectly viable alternative to metal in many cases.