The medical tubing and catheter markets still face significant challenges across the global supply chain, especially regarding extended lead times, but overall, a general settling is happening within the industry, with more predictability. Medical device manufacturers (MDMs) have found workarounds, alternative materials, and back-up suppliers to keep things running as best they can. These economic and regulatory challenges are spilling over into 2023, especially in the EU, where stricter regulatory processes are now in place. And, thankfully, as COVID-19 continues to wane, business volume is picking up.

“We are seeing a steady increase in demand for medical tubing, especially now that elective surgeries are ‘back on the table,’” said Matt Bills, senior vice president of extrusion technology and innovation for Spectrum Plastics Group, an Alpharetta, Ga.-based provider of development through scaled manufacturing of critical polymer-based components and devices for medical and other markets.

However, production can only go as fast as the supply chains that supply it. Proactive companies have seen the pandemic slowdown not only as an opportunity to upgrade their supply chains, but to also develop innovative new products.

“These challenges differ around the world, but they all require one thing—innovation,” said Mike Winterling, chief operating officer for USA and Europe for Junkosha USA, an Irvine, Calif.-based provider of tubing for medical devices. “Innovation is needed to not only improve patient outcomes, but to provide clinicians and other end users with technologies that make their lives easier, reduce costs, and save time. For this reason, continuous innovation must be at the heart of the healthcare sector’s requirements. Without this, unmet needs will continue to be just that—unmet.”

Although the medical extrusion industry slowed significantly during the pandemic due to hospital and elective surgery shutdowns, the development of new and innovative medical extrusions has continued to grow. “The tubes/parts developed during the pandemic are now production parts and medical extrusions today that are growing at approximately 25% on an annual basis, despite very persistent supply chain issues,” said Tim Steele, CEO and founder of Peterborough, N.H.-based Microspec Corporation, a custom extruder of medical tubing and profiles.

Innovative MDMs are eager to develop new products that take advantage of technologies such as Internet of Things (IoT), artificial intelligence (AI), and additive manufacturing (AM) as a good way to differentiate themselves from their competitors. Home care, in particular, is a hot market. With competition so fierce, being first to market is a huge advantage. To get new products to market faster, more MDMs are utilizing prototyping earlier in the design stage to innovate more quickly and shorten the production process.

“The medical tubing market always pushes the innovation envelope, requiring advancements in technology as it relates to equipment and polymer design,” said Lawrence Alpert, manager of medical extrusion technologies for Graham Engineering Company, a York, Pa.-based manufacturer of integrated extrusion systems for various industries, including medical devices. “We are seeing more developments and innovations from our partners in measurement and gauging in data capture from our processes. This data is important as it will reduce validation and process monitoring overhead through automation.”

The last two years have been a wild ride with shocking supply chain disruptions and loss of business and cutbacks, followed by sudden influxes of demand, which have been very difficult for the medical device community to handle. It was also challenging for small medtech companies that did not have the resources to compete against larger companies over the longer term, especially for critical material. However, some of these companies have developed innovative, niche, low-volume products that will likely drive long-term value over the next five to 10 years and lead to next-generation devices.

Although there has been a tremendous surge of investment by MDMs and their contract manufacturers (CMs) to respond to the supply chain situation, “it still takes a while to purchase the needed capital equipment and get it up and running,” said Barry Schnur, CEO of David Schnur Associates, a Redwood City, Calif.-based global technical sales organization supplying materials and components, including polymers and metal tubing for the medical device industry. “It’s also been challenging to get skilled engineering and manufacturing expertise to U.S. and global manufacturing facilities.”

On the technology side, MDMs are investing in newer tubing solutions, which some companies are more likely to adopt when their material choices are severely limited by supply chain issues. “For example, the market shortage of fluorinated ethylene propylene [FEP] heat-shrink tubing has made everyone more open to the idea of trying something different, either with a reflow process, outsourcing their process, or going in a different direction,” said Schnur.

The medical tubing market is currently balancing between two states, observed Adam Nadeau, technical director of filtration technologies for Saint-Gobain Life Sciences, a Solon, Ohio-based provider of fluid management solutions and components for the life sciences. “On one hand, we are dealing with raw material constraints and supply issues on a wide range of materials, causing OEMs to search for suppliers who can support legacy products,” he said. “On the other, device innovation continues and OEMs are reaching out with new and challenging tubing requirements.”

Latest Trends

The medical tubing sector is under various pressures to provide cost-effective and high-quality products over shorter timescales. Tubing in general is getting more complex with micro-sized features. Co-extruded, multi-lumen tubes, and profiles with outside diameters of less than 1 millimeter are becoming common. “The trend is moving toward smaller, multi-layer, multi-lumen geometries utilizing custom compounded polymers, including active pharmaceutical ingredients,” said Alpert.

More advanced catheters with greater functionality are in high demand. Neurovascular interventions are growing in popularity because they help clinicians deliver complex therapies more efficiently, reducing costs and boosting quality of care. Overall, the trend toward miniaturization of catheters is driven by potential uses in neurovascular treatments, including the delivery and deployment of coils and stents for stroke or aneurysm therapies. By making procedures less invasive, risk of complications is reduced for patients and recovery times are shortened.

“The move toward procedures using progressively smaller catheters and guidewires continues to increase,” said Winterling. “Smaller medical tubing solutions that can readily access hard-to-reach places are in greater demand from medical device manufacturers. Added to this is the need for sophisticated catheters that can send and receive diagnostic signals into the body or provide therapy—in other words, active catheters.”

At the high end of the tubing market, “there continues to be greater adoption of new hybrid delivery shaft technologies that involve really complex, high-performance metal drive shafts and components, such as cable tubes, unique torque tube products, or laser-cut hypotubes combined with a lubricious liner and a heat shrink polymer jacket,” said Schnur. “These newer technologies are increasingly displacing older, braid-reinforced devices in next-gen devices.”

The push for smaller, higher-performance, thinner-walled products is also driving requests for materials that have different combinations of seemingly contradictory properties: for example, more rigid but more flexible, or soft and pliable but still highly lubricious. “We see companies doing a lot of interesting things to address this, with the polymer itself, coatings and surface modification technologies, or with manufacturing processes,” said Schnur. “This is particularly applicable to structural heart devices that are delivered to more challenging valves, or neurovascular delivery systems that must navigate through smaller, more tortuous pathways.”

As MDMs continue to develop smaller, more flexible products, tubing providers are being challenged to develop automated solutions that can process thin-walled, low-durometer materials and maintain consistent quality and reliability.

“We see OEMs seeking a clean, burr-free cut and finish for both metal and plastics with minimal need for secondary processing,” said Rich Warren, chief commercial officer for Medical Manufacturing Technologies, a Charlotte, N.C.-based provider of catheter manufacturing and grinding technologies. “Process automation is also key to reducing dependency on vendors, addressing labor challenges, reducing downtime, and improving control in production lines.”

What OEMs Want

MDMs are looking for any process improvements that will speed up production and delivery. This often involves adding services, such as improved inspection, or eliminating secondary steps when possible due to greater production efficiencies or use of alternative materials. The number-one demand by MDMs is thinner walls, which means more available space (more functionality) inside the catheter compared to standard tubing of the same diameter.

“We as processors must be creative with our ability to get walls thinner for thermoplastics,” said Bills. “For example, up until a couple years ago, thin was considered 0.005-inch thickness at a 0.1-inch diameter and ultra-thin walls were 0.002 inches at the same diameter. Today, Spectrum Plastics Group has created a new classification of tubing that we refer to as sub-ultra-thin-wall-tubing, which is tubing with a 0.5% wall thickness-to-diameter ratio. In other words, the same 0.1-inch diameter can now be made with a 0.0005-inch wall thickness.”

Thinner walls and the enhanced functionality mean that catheters and guide wires must also get smaller, with improved navigability and lubricity, to take the intervention deeper into the body. This shift toward miniaturization characterizes a continual cycle of innovation for the tubing sector, especially for neurovascular therapies and below-the-knee procedures.

“Many customers are pushing the limits on the overall size of their devices,” said Winterling. “These efforts often include requests for thinner and tighter tolerance materials that still maintain the mechanical performance necessary for the integrity, trackability, and performance of the finished device.”

“Some customers are looking for customized solutions that impart additional functionality to the tubing,” added Nadeau. “This could be something as simple as embedded color striping to mitigate in-house assembly or end-user connection errors. Or it can be something like a complex profile geometry with embedded layers of a custom material formulation that is targeting a specific level of electrical dissipation.”

Regardless of the level of innovation, MDMs always want higher output stabilities and improved ability to hold tighter tolerances. In some cases, they are tasked with “lowering the shear heat and residence time, as some materials [bioresorbables, active pharmaceutical ingredients] require this to ensure stability,” said Alpert. “In addition, our customers often ask for lower volume and residence time in the extruder for their high-cost resins.”

OEMs are also looking for automated solutions that increase precision, output, and quality, while reducing operator input and time to market. Automated systems that help meet this growing demand include Medical Manufacturing Technologies’ automated process that integrates the Glebar Micro Centerless Grinding Machine with a Syneo Tube Feeder for metals and plastics. “Having a broad portfolio of technologies and our ability to integrate them allows customers to capitalize on seamless machine interactions and de-risks customer automation projects,” said Warren.

Customers are desperate for any improvements that shorten lead times, which can still be a year or longer in some cases. These shortages and inconsistencies have pushed some companies to vertically integrate tubing extrusion in-house. Catheters are especially in high demand in the surgical sector and the consequences of long lead times not only inconveniences manufacturers but also put patients at risk by creating delays for their procedures. This is a significant unmet need in the market. For example, Junkosha continues to face material shortages in polytetrafluoroethylene [PTFE] liners and FEP-based heat shrink tubing. As a result, “the company plans to increase investments in its medical component manufacturing plant over the next 18 months, with the aim of supporting the material shortfalls in these areas,” said Winterling.

Another heat-shrink advancement is the incorporation of lubricious additives into the tubing to make it smoother and more friendly to the body. Although the additives themselves are not new, the ability to provide an additional lubricous surface on Pebax or Polyolefin heat shrink tubing is a new advancement. “The recent lack of availability of traditional heat shrink tubing for reflow makes a stronger case for evaluating whether Pebax heat shrink tubing can be used as the outer jacket,” said Schnur. “Because the reflow heat shrink tubing market has been so jammed, device companies are looking at other materials as alternatives.”

Technology Advancements

Catheter manufacturers are calling on equipment manufacturers for innovations that reduce the wall thickness of the catheter liners to less than 0.00075 inches in order to add functionality, enhance trackability, and provide the ability to treat a broader range of patients. Junkosha has developed a range of medical tubing innovations, including the first ultra-small peelable heat shrink tubing [PHST]. “This tubing solution is suited for laminated jacket coating of tiny guide wires [diameters as small as 0.011 inches], leveraging the fact that PHST has a recovered interior diameter [ID] down to 0.009 inches,” said Winterling. “These miniature guide wires are perfect for procedures that target hard-to-reach locations in the brain.”

In response to customer needs, Cobalt Polymers has recently developed a new 74D version of its 2:1 and 4:1 ratio Pebax heat shrink tubing. It offers engineers more rigidity while maintaining flexibility, additional hardness and column strength, and excellent clarity, making it a great option for neurovascular, peripheral vascular, and implant delivery applications when a more robust polymer matrix is needed. “The new 74D 4:1 ratio Pebax heat shrink tubing is most comparable to thin-wall polyethylene terephthalate [PET] heat shrink tubing,” said Schnur. “It offers more hardness than other Pebax tubing, but still retains the flexibility of thermoplastic elastomers. It also offers the unique properties of Pebax, including bonding to an underlying substrate and eliminating the reflow process.”

Electrical conductors can be embedded in the walls of the tubing, or be carried through lumens inside the catheter, to provide conductive paths along alloy wires inside the tube’s wall. This type of tubing is constructed of an insulation material or multiple material types (hybrids)—reinforcement can be either coiled, braided, or linear. These advances with conductors are important groundwork for moving toward more active or “smart” catheters. In fact, for some advanced surgical procedures, having smaller, more flexible, and higher-signal capacity catheter-based devices that can send back signals in real time is absolutely essential.

Smart catheters have electrical or sensing functions that provide less-intrusive and higher-quality diagnostic imaging. However, transmitting electrical signals through narrow catheters can be complex. Solutions such as the Junkosha Multi-Channel Transmission Cable (MCT) represent a breakthrough for reducing the size of tubing-based diagnostic and/or therapeutic medical device cables.

“The MCT solution enables multiples of four signals to be brought together in one transmission line, therefore significantly increasing the respective signal capacity per unit diameter,” said Winterling. “These cables are designed to provide individually insulated microwires with optimized shielding/grounding, optimizing for key characteristics like signal transmission quality, minimizing signal loss, and reducing size. This enables new data-rich signals for therapies such as intracardiac echocardiogram, ultrasound endoscopy, and intervascular ultrasound.”

New England Tubing Technologies, a Lisbon, N.H.-based provider of medical tubing, offers a proprietary product called “eTubing” where wires are embedded into the wall of the tube—”an efficient design when device requirements consist of electrical capabilities and fluid or air flow,” said Derek Maccini, process engineer for New England Tubing Technologies. “Requested solutions vary from zip tubing in various geometric orientations—parallel, triangular, and square—to conductors placed concentrically within the tubing wall.”

Biopsy and specialty needles have always been a challenge for MDMs. These high-precision instruments require tight tolerances, customized shapes, and precise repeatability. Medical Manufacturing Technologies (MMT) has developed its Tridex SG1645, which integrates robotics and pallet changers to increase repeatability while maintaining quality for lights-out operation. The company continues to develop integrated solutions for single- and multi-lumen catheter manufacturing processes that reduce operator touch-points during production and increase throughput. These turnkey automated systems are integrated with MMT’s service and support platform, TotalCare, which keeps production running 24/7. For low-volume specialty manufacturers, MMT developed a new, simplified electrochemical grinding machine for metal tubing cutoff, which allows for manual operation while using burr-free cutting technologies.

“Our goal is to always help our customers achieve higher throughput, minimize downtime, and reduce costs by automating material processing and inspection,” said Warren.

Medical extrusion machines are basically unchanged compared to several years ago, but their controls are becoming increasingly sophisticated, making smaller sizes and complex features with super-tight tolerances possible.

“Touch screens have replaced the old control panel,” said Steele. “Integrated digital control of the entire extrusion line is becoming the norm, allowing very precise adjustments that improve quality and productivity. The latest vision systems also make measuring fast and efficient. Simply touch the spots on a touch screen image of tubes that are to be measured and step back. The machine takes over and completes the measurement in seconds.”

Technologic advancements that have been most beneficial to Graham Engineering Company are upgraded measurement systems that offer higher resolutions and faster speeds. “We can now measure parts in process such as tubes and profiles and make needed parameter changes to ensure we hit our part tolerances,” said Alpert. “These systems not only provide measurements and immediate feedback and, when used in conjunction with the line’s human-machine interface, we have complete control and historical data from each run.”

Moving Forward

As devices get smaller and more complex, the demands for tubing become more challenging. Traditional materials have reached their limits of performance for many advanced tubing applications. MDMs feel the need to go beyond just multi-layer tubing of traditional materials and create novel formulations, with new and unique materials, to meet the growing number of new or potential applications. To assist this effort, their tubing partners continue to push the edges of technology, utilizing advances in online measurement, software processing, Internet of Things, lasers, and other technologies to keep up with more complex medical device designs. As walls become thinner and IDs get smaller, these methods—often creatively combined—in the hands of experienced engineers and technicians continue to improve product consistency, quality, and manufacturing efficiencies. Materials and their properties continue to advance, with increasing numbers of formulations and variety of additives or additive combinations.

Innovation by tubing manufacturers continues to meet MDM needs. They look for ways to use technologies in unique or combined ways. For example, the main role of AM in tubing is to form certain parts (tips and connectors) or produce rapid prototype dies/tooling to test small extrusion runs. A recent breakthrough has been accomplished by Spectrum Plastics Group, which has developed a proprietary process that enables the company to 3D-print infinite lengths of tubing for initial testing. “There are so many benefits to doing this,” said Bills. “For instance, if the customer has a multi-lumen design in mind but doesn’t know if their selected geometry or durometer are correct, both time and expense can be saved by not having several multi-lumen tools created and waiting weeks or even months for the results. We have the ability to use the exact resin the customer intends to use in their design and can usually deliver within a week, or in many cases, a few days.”

So far, Spectrum Plastics Group has used its new process to 3D print fully functional tubing for prototyping and testing. It continues to refine the robustness of the final product and test the viability of using its 3D-printed tubing as a sustainable manufacturing process.

As medical device complexity increases and manufacturers strive to produce ever smaller products, tubing manufacturers are constantly pushed to develop products that are thinner, stronger, and more flexible. For example, SPG engineers continue to push the envelope in terms of performance, space, and size for their delivery systems. “We have successfully produced tubing with a diameter of 0.1 inches and a wall thickness of 0.0005 inches,” said Bills. “We accomplished this through free-air extrusion while maintaining a statistically well in control process [3.8 Cpk].”

Automation continues to improve the quality, accuracy, and efficiency of manufacturing. Time to market is shortened because errors are greatly reduced, any variances that come up can be adjusted in real time, and data analytics make validations much easier. Automated technology has been applied to the latest inline measurement systems suppling instantaneous feedback to the operator and control system. Offline measurements are now automated, improving testing time and accuracy. “What used to take 10 to 15 minutes per sample can now be accomplished in seconds,” said Alpert. “The best part is having a single point to access and/or automate data collection, as well as being able to sort product specific information on not only the part being within specification but the process as well. Servo-driven extruders, gear pumps, and downstream equipment have made equipment variation a non-factor, which means all the focus and effort can be put into the extrusion process itself and not having to fight with other variables.”

Looking to the future, as increasingly intricate procedures become viable, medical devices will get smaller and more complicated. Device manufacturers are currently using combinations of braiding, coils, laser cut tubing, and multiple durometer jacketing materials to increase flexibility where it is needed, but still maintain the mechanical performance necessary for a smooth delivery.

“These innovations drive organizations like Junkosha to not only innovate on a product level, but to also find ways to provide its solutions in an efficient and cost-effective manner that meets all of its customers’ needs,” said Winterling. “In effect, today’s innovations will be tomorrow’s essentials.”

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Mark Crawford is a full-time freelance business and marketing/communications writer based in Corrales, N.M. His clients range from startups to global manufacturing leaders. He has written for MPO and ODT magazines for more than 15 years and is the author of five books.