Polymers are serving critical roles for the medical field, from single use instruments to life-preserving in vivo devices. These instruments and devices are made from a variety of plastics and high performance polymers, including:
- Polyetheretherketone, or PEEK
- Polyethylene, or PE
- Polypropylene, or PP
- Polystyrene, or PS
- Polytetrafluoroethylene, or PTFE
- Polyethylene terephthalate, or PET
There are others, but the above polymers are most widely used in plastic instruments and devices. Among them, PEEK is a primary biomaterial, which means it can be used in or around the human body without causing harm to the patient.
If all polymers and their medical applications are considered, there are at least hundreds of uses for medical plastics. Polymers are useful for a variety of medical applications, from repairing blood vessels to replacing heart valves. They can also be used to anchor a bone plate or keep a suture in place. High performance polymers like PEEK are particularly notable, as their excellent physical properties ensure they can fit into many applications.
What are PEEK’s applications in medicine?
PEEK exhibits excellent biocompatibility, verified through extensive testing. It can be used in implantable devices and implanted permanently, without toxicity to the patient. Given PEEK’s comprehensive biocompatibility, it has found use in several fields of medicine, including:
- Spinal fusion – PEEK was introduced to medicine first as an interbody fusion cage, intended for use in spinal fusion operations. That was 20 years ago, and PEEK is now the frontline choice for interbody fusion cages, replacing titanium in many instances.
In fact, PEEK’s success in spinal fusion procedures has pushed medical engineering firms to develop better PEEK spinal implants. This new generation of interbody fusion cages attract bone-in growth better than previous cages, allowing for better integration between the implant and native bone.
Spinal fusion can be used to treat several debilitating conditions, like degenerative disc disease, spinal stenosis, scoliosis, spondylolisthesis or tumors. PEEK can be used to give these patients relief from pain and loss of motion and can be used when there is serious trauma to the spine.
- Trauma fixation – PEEK’s impressive fatigue and pull-out resistance and resilience make it an ideal choice for trauma fixation components, like anchors and screws. PEEK bone plates are also being considered, due to PEEK’s impressive flexibility and its ability to maintain its shape. Trauma fixation devices and components must be able to withstand repeated tensile stress, and PEEK stands out in this regard.
- Orthopedics – PEEK is found in many orthopedic screw systems and suture anchors. Beyond that, PEEK can be used in knee and hip replacements, as it is an ideal weight-bearing material. PEEK’s fatigue strength and ideal modulus also factor in as both are important traits to have in a stress-bearing device.
Acetabular cups produced from PEEK exhibit strong wear resistance, according to the Journal of Engineering in Medicine. A study published in the journal determined that such acetabular cups only wear at a rate of 1mm3 every 1 million cycles. In short, PEEK is a long lasting, tough material for tough orthopedic applications.
- Cardiovascular – In addition to its remarkable strength, durability and flexibility, PEEK’s extensive processability and hydrolysis resistance are also considerable. This means the polymer is a perfect fit for the cardiovascular environment, and its uses in heart and pulmonary medicine are expanding quickly.
PEEK can be converted via extrusion, which can be used to make uniform, long strands of medical tubing. PEEK tubing is prized for its low coefficient of friction, so it can be pushed and steered through the cardiovascular network without causing damage to artery walls.
PEEK tubing can be used to deliver other cardiovascular devices, like a replacement valve or used in implantable defibrillator components. PEEK is also used as an anchor in a few cardiovascular surgeries, including the less invasive ventricular enhancement procedure, or LIVE.
- Dental – PEEK’s potential in dentistry is also impressive, and it is used in partial dentures and in implants. It makes sense for partial dentures because PEEK can be optically matched to the patient’s dental tissues, so they look identical to the patient’s teeth and gums. It is unlikely that anyone would notice anything made from PEEK in anyone’s mouth.
In addition to PEEK’s superior aesthetics, PEEK doesn’t affect the patient’s taste, it won’t trap heat and it’s lightweight, making for a more comfortable fit.
PEEK’s strong resilience and favorable modulus make it a frontline choice for dental implants. It integrates well into bone, which is a deciding factor for an effective dental implant, and it is flexible enough to handle biting and chewing forces well.
Medical plastics are one of the most encouraging areas of biomedical research, and their role in the industry will only expand as technology improves. In many ways, the future is already here for high performance polymers like PEEK. With more than 20 years of success in spinal fusion, orthopedic, arthroscopic, cardiovascular, dental and trauma fixation applications, PEEK is the biomaterial of choice for many.