NHS aims to be the world’s first net-zero national health service. The NHS in England is responsible for around 20 million tonnes of carbon dioxide emissions annually and spends over £50 million a year on carbon permits.
Single-use medical device plastics are used in surgery worldwide as a necessary part of safety and efficacy. Device origin is well documented in production teams and regulatory documentation but mostly unknown beyond the manufactures name on the box. This article aims to give a snapshot of where medical device plastic comes from, what happens when it is disposed of, and why it may not be as bad as you think.
High-income countries generate, on average up to 0.5 kg of hazardous waste per hospital bed per day and an operating theatre list of around 6.5kg. This is the modern journey of medical plastic to and from an operating room.
Step 1: The Plastic in its original form
Medical plastic products have become more advanced as the global market for high-quality medical devices continues to expand. Such devices have become a necessary and vital component in the modern healthcare system. Medical plastic products are available in a wide assortment of devices. From test equipment like vials and beakers to surgical instruments, catheters, and implants, plastics are used more and more for their high performance, lightweight, and lower costs. Single-use devices are safer than reusable ones (reprocessing comes with environmental impact as well).
Doctor Code: Do No Harm
Diverse medical applications, product durability, and biocompatibility are all important factors that original equipment manufacturers (OEMs) of medical plastic products must consider to meet market demands. Just as important, medical-grade plastic materials must meet regulatory requirements throughout the globe. To ensure that the plastic material is safe and effective for medical products, polymers for medical devices are generally made of thermoplastic materials.
Polypropylene is a cost-effective medical-grade plastic material and is used where steam-sterilized medical devices are necessary. In addition to resistance to steam sterilization, mechanical performance properties of polypropylene include durability for the number of cycles it can be reused. Its recyclability also makes it an attractive medical-grade plastic. Polypropylene is a lower carbon plastic than others (for example, PVC and Polyethylene) therefore being a lower impact material to use.
Step 2: Using self-retaining retractors as an example.
For illustration, this article uses a well-established and commonly used surgical retractor (Galaxy II from JUNE Medical) made out of Terlux. A plastic injection-molded single-use, self-retaining surgical retractor. Approximately 10 000 self-retaining ring retractors are used in the UK annually. Modern versions are lightweight, with the most innovative frame weighing in at only 62g.
Calculation of 1 Year Use of 1 device (production Co2) 62g per unit x 10,000 units = 620kg *3.5k (as the upper value) is 2170kg = 2.17 tonnes CO2 / year from manufacture as an upper limit (1.24 tonnes as lower) A self-retaining surgical retractor (Galaxy II) available via NHS Supply Chain
Terlux Processing: Injection Molding, Film Extrusion, Profile Extrusion, Sheet Extrusion, Blow Molding, Thermoforming
Delivery form: Pellets
Special Characteristics: Transparent, melts at 220 degrees Celsius
Delivered via boat transport to the United Kingdom in containers, Terlux is shipped to the manufacturing site in Brighton, where it is stored in controlled environments. Terlux beads (colored or clear) are then melted and/or mixed and injection molded in large machines that fill metal molds with melted Terlux into the unique shape of Galaxy II frames and cam locks.
Parts are inspected, cleaned and quality checked by trained staff, and put into a clean room for assembly. Frames are then hand assembled according to strict work instructions, and again quality checked. Clean rooms are fascinating places that look intimidating: everyone is fully covered in protective gear, and nobody talks much. Concentration levels are VERY high!
The Galaxy II retractor is then packaged into Tyvek bags and sent to Steris for sterilisation.
Step 3: During surgery
John Radcliffe in Oxford calculated their theatre waste:
Clinical waste/list = 6.15kg/list
Recycled waste/list = 1.74kg/list
Surgical retractors like Galaxy II are used in a range of procedures, and over 10 000 self-retaining ring retractors are used in the UK every year. It is a surgical instrument used to separate and manipulate the edges of a surgical incision or wound or to hold back underlying organs and tissues so that body parts underneath may be accessed.
Surgical assistants sometimes assist surgeons in the process of retraction, but the staff is more expensive, and the health and safety concerns of staff for tissue retraction are well documented.
Self-retaining retractors are lightweight, gentle on the patient’s tissue, and last for as long as they need to without getting tired or needing to shift position. They are adaptable to almost any surgery and come with a range of different hooks and accessories. Modern ring retractors have safety cam locks that cannot break off instead of screws and use new materials that are strong, yet weigh only 62g – a big benefit from an environmental perspective.
The retractor is placed above the incision, fastened with small skin hooks, and then removed once the procedure is complete. It is discarded into clinical waste together with approximately 6kg of other waste and managed as per the hospital’s waste management policy.
Benefits: reduced need for staff, improved working environment, better access to the surgical site, less crowded operation room, always sterile and available. Downside: Single-use plastic.
Step 4: The Burning
Incineration of waste has been widely practised, but inadequate incineration or the incineration of unsuitable materials results in the release of pollutants into the air and in the generation of ash residue. Incinerated materials containing or treated with chlorine can generate dioxins and furans, which are human carcinogens and have been associated with a range of adverse health effects. Incineration of heavy metals or materials with high metal content (in particular lead, mercury and cadmium) can lead to the spread of toxic metals in the environment.
However, modern incinerators operating at 850-1100 °C and are fitted with special gas-cleaning equipment and comply with the international emission standards for dioxins and furans.
Clinical waste is divided into different types, depending on the nature of the waste. For example, it is really important to separate highly-infectious, infectious and non-infectious waste.
Highly-infectious materials are treated separately in High-Temperature Energy Recovery Incineration Facilities such as Grundon.
Infectious waste is sent to an Alternative Treatment facility where it is rendered safe through a unique steam treating process.
Highly-infectious materials, sharps bins, pharmaceuticals, cytotoxic/cytostatic medicines, and anatomical waste will be sent to the High-Temperature Energy Recovery Incineration facility. Not only does this divert waste from landfill, but the steam created is used to power a steam turbine to generate electricity.
Offensive waste (also known as non-infectious waste) can be sent to special Energy from Waste facilities, ensuring zero waste to landfill and generating renewable electricity for export to the National Grid.
The output of gas from the burning of clinical waste is
Step 5: Where can surgical staff now make the biggest impact?
Waste separation in the operating theatre is hugely impactful.
Oxford University Hospitals Trust has reduced the amount of waste going to landfill or incineration by introducing recycling into the operating theatre setting. Previously all waste from clinical areas was disposed of via orange clinical waste bags. There are now recycling bins in every anesthetic room of the three largest operating suites, as well as in recovery and staff rest areas. Waste segregation has become routine for many members of staff, and approximately 22% of theatre waste is now recycled.
Decades of work to reduce single-use plastic has resulted in much leaner and less wasteful hospitals, but there is more to be done. Understanding what aspects of medical surgical devices are necessary (for example, those that cannot be safely or cost-effectively reprocessed) is a step in the right direction for environmentally aware hospital staff.
Waste incineration has improved so much in the last few years that the focus is shifting to other places in the chain to innovate for a greener alternative. In addition, with the progress made in modern manufacturing materials and processes, the better Innovation from an environmental perspective is to create products using materials that “burn better”, weigh less and produce less output to offset.
Angela Spang is a Swedish-born medical device innovator. She lives in the UK and has won numerous awards, most notably The Queens Award 2021 for Innovation for her GalaxyII surgical retractor.