Three Major Innovation Opportunities for Biomedical Textiles

Biomedical textiles are gaining significant momentum for use in medical devices to facilitate less invasive surgical procedures. Textiles made from synthetic and metallic biomaterials offer a surprising combination of versatility and strength. They can be strong enough to hold joints and bones together, yet delicate enough to be used in sensitive tissues.

The advancement of textiles has historically been somewhat limited by an outdated business model and reluctance by textile developers to move outside their comfort zone when it comes to addressing complex textile challenges. They have instead favored established, high-volume textile production. Today, that is changing. Textile developers are working with their medical device OEM customers to redefine a space ripe for innovation. The right combination of creativity, infrastructure, capabilities, and experience is leading to better products that expand the boundaries of what’s possible.

The nearly limitless combination of patterns and advanced geometries that can be created by today’s engineers through a blend of material selection and software programming allows characteristics such as porosity, flexibility, thickness, and stability to be completely controlled and customized. Implantable fabrics are also inherently chemically inert, corrosion-proof, and offer favorable wear resistance. This has created exciting opportunities to use textiles unlike ever before. As a result, textile applications now span across many applications, but three where they have the potential to especially add innovation in the year ahead and beyond are orthopedics, cardiovascular, and robotic surgery.

Cardiovascular
As textile structures have become more innovative, with complex and fully customizable geometries and implantable fabrics that are no longer limited to traditional applications and can actually support and promote the healing and even the regeneration of damaged cardiovascular tissue. Textiles formed via knitting, braiding, or weaving of medical-grade fibers are now used to create biocompatible heart valve fabric, aortic arch reinforcement, stent graft covering, carotid artery repair fabric, tissue grafts, and more.

Today’s textiles have the flexibility and shape transformation capabilities to be engineered for insertion through a small catheter and to expand within the vessels, allowing for minimally invasive delivery methods without sacrificing any mechanical integrity. This is particularly beneficial for patients with small vessels, and for repairs in the three branches of the aortic arch, which has long been challenging. Even in thoracic surgery, where pressures are significantly higher than in abdominal areas, textiles have proven very successful due to the development of high-performance medical grade yarns and dense fabric constructions. The goal continues to be to make smaller, lower profile devices to facilitate less invasive procedures.

Warp knitting is especially ideal for creating textile products for vascular applications such as mitral heart valve replacement because it can produce very thin, dense textile structures that prevent blood leakage around the valve. Porosity can be tailored to recruit the desired cell by size, creating specialized regions of tissue regeneration. Densities can be rapidly changed so you can transition from dense to porous within a single fabric. For cardiovascular fabrics, this means blood leakage can be prevented inside the valve while native tissue ingrowth is encouraged outside. Knits are very compliant, thus allowing the implant to stretch and move with the body and ultimately reducing patient discomfort and restoring natural mobility.

An area poised to see increasing growth and innovation is transcatheter aortic valve replacement (TAVR). With a typical heart valve replacement, a patient is put on a bypass machine while the surgeon works to excise the old valve, put the new valve in, and suture the patient up while hoping for the best outcome. Medically fragile patients struggle to survive the intense nature of a bypass, and survival rates among these populations are low. Textiles can be incorporated in TAVR products to prevent abrasion and encourage tissue growth. For example, a braided sleeve can go over a stent so, in a failure mode, the stent will rub against the textile material rather than the patient’s tissue. Additionally, textiles can help develop a thrombus on the surface so blood doesn’t pass through, playing an integral role in the clotting cascade.

Orthopedics
Medical device OEMs in the orthopedic space are using biomedical textiles to offer minimally invasive approaches for applications from soft tissue repair (e.g., tendons and ligament tears) to hard tissue repair (e.g., spinal stabilization). Because biomedical textiles are inherently compressible and flexible, they are excellent for less invasive delivery applications that benefit from shape transformation. This may be an application where a device is inserted through a small hole and then expands in the body. Also, their compatibility with biologic structures and ability to be tailored to the needs of the procedure means patients may benefit from simpler procedures, faster healing times, and less risk of complications or rejection.

Braided textiles with a low profile and high tensile strength have long been deployed in orthopedic applications to allow a surgeon to secure soft and bony tissue. More recent technology advancements allow for greater customization of braided textile properties (such as variable density) to facilitate a simpler and more durable surgical repair. Woven and knitted biomedical textile structures have also become increasingly sought after as foundations for orthopedic implants and anchor points for attaching soft tissue—largely due to their strength, compliance, and inherent capabilities for promoting tissue ingrowth. These textile structures can distribute load over a larger surface area and be engineered to mimic the behavior of the ruptured tendons and ligaments they are replacing.

For tissue engineering applications, composite scaffolds can be created using hybrids of osteoinductive biologic and synthetic materials that are well-suited for spinal fusion and long bone fractures. These biomedical textile composites have a high level of stability and localized containment not possible with other common scaffold materials such as sponges, foams, and porous metals.

Surgical Robotics
Robotic platforms have the potential to bring greater precision and less invasive approaches to a huge variety of applications across general surgery, urology, orthopedics, gynecology, cardiovascular, and more. Robotic surgery opens the possibilities for greater geometrical precision—which is especially beneficial for anatomical areas that are difficult for a human surgeon to access—and may result in shorter hospitalizations. From catheter insertion to cardiac ablation, by working alongside human surgeons in the OR, robots can help improve the result for the patient. As the surgical robotics industry continues to evolve and become more advanced, close collaboration between textile developers and medical device OEMs will result in greater innovation and the potential for better patient outcomes.

Textiles are proving to be a viable and advantageous alternative to traditional metal in robotic devices, thanks in large part to their ability to be thinner, lower profile, cost-effective, and to support better articulation. Incorporation of textiles into surgical robotics systems such as robotic arms enables greater flexibility and smoother movements. For a wide range of surgical applications requiring gripping, cutting, or suturing, textiles can give the hand on a robotic device more degrees of freedom and improved orientation. Textiles are now commonly being used as tethers for actuators, and even as replacements for stainless steel wire in robotic-assisted laparoscopic staplers. Contrary to some misconceptions, transitioning from metal to textile components in robotic devices does not mean sacrificing strength—in fact, in some cases, textiles using modern high-performance fibers can be even stronger than metals, while also having the flexibility to conform to twists, bends, and grooves in a device.

Braided textiles usually prove to be ideal for balancing the size and strength requirements in robotic surgery platforms. Braids can bear significant weight, and the cylindrical shape makes them well-suited to wind through cannulas, a transcatheter delivery system, or to conform to twists and turns. Textile characteristics can be customized in different zones of a single braid—for example, enabling a high degree of flexibility at the distal end of a braid while being stable in the middle for maximum load bearing. Highly skilled hand fabrication capabilities can even create different splices, loops, and end terminations that can be used with other braids or terminations within a robotic device.

Conclusion
The dynamic between textile engineers and medical device OEMs is shifting to enable greater innovation and a move away from accepting the status quo. Teams that combine engineers and specialists with expertise that ranges across textiles and medical device development bring a better understanding to how the finished product will need to perform in the real world, which greatly benefits the overall outcome of the project. Closer collaboration, rapid and iterative prototyping, and a willingness to explore more exciting and intricate design options is taking biomedical textiles to a new level.

Today, designs can be highly complex and textile manufacturing can contain many processes, including but not limited to yarn twisting, yarn plying, bobbin winding, braid or fabric manufacturing, rewinding, scouring, heat setting, cutting, hand fabrication, packaging, labeling, and quality inspection—all of which may be customized for a specific product and which must meet the guidelines of ISO 13485.

Done right, textile properties can be isolated to localized regions of fabrics thanks to modern textile forming equipment. Raw material properties and bio textile geometry can be blended to yield properties and performance characteristics previously unimagined. This significantly reduces the risk of rejection by the body, while helping restore and preserve the patient’s targeted body function.

Not only do textiles have optimal mechanical properties, but by using the right fibers and orientations they can elicit excellent responses to the clotting cascade, which can be beneficial in many clinical applications. They also offer conformability important in the areas of carotid patches, heart sacs, and soft tissue repair. Because they are highly biocompatible, fabrics can help restore more of the body’s natural anatomy and even promote accelerated tissue growth around an implant. Textiles can also preserve motion, making them ideal for products such as spinal stabilization devices.

As a result, biomedical textiles are now increasingly used in vascular grafts, heart valves, annuloplasty rings, catheter-based delivery systems, neurovascular products, orthopedic sutures, orthopedic implants, pledgets, small joint repair, tissue scaffolds, spinal stabilization products, scoliosis treatment, cerclage cables, and a range of robotic surgery products. Looking at 2021 and beyond, the possible applications of biomedical textiles will continue to grow and support less invasive surgical procedures.