Like the human bodies they’re designed to treat, medical devices are often composed of disparate systems. Linking those systems, much like the vasculature of the human body, are systems of tubes.
Tubing provides passage for gas, fluid, electronics, and even micro-sized devices to travel seamlessly. With modern designs, tubes are often slated to play double-duty, housing multiple components through different lumens with various internal sizes and wall thicknesses.
Since tubing plays such an integral role in medical tech, designers continue to push the limits with new tubing solutions. Advances in material design, extrusion and production techniques are constantly being released, improving design and functionality across the board.
Production improvements are vital for tubing innovation. Better techniques for extruding thermoplastic elastomer tubing have improved biocompatability and processing, and new extrusion technology offers synthetic materials with low extractible content. That combination improves biocompatability, either when used in the body or with pharmaceutical products.
Other improvements include bioresorbable tubing, designed with custom degradation profiles to allow materials to perform in the body for a fixed period of time. New materials also allow for improvements in radio-opacity, anticoagulation, lubricity and biostability.
Formulations can be customized to deliver unique properties for project applications, such as UV-cured silicone materials, which cure more completely and at a higher rate than traditional platinum-cured silicone for more cost-effective production. Antimicrobial modifications can be incorporated into the material to help reduce infections.
As devices become more complex, tubing must follow, allowing for more devices, structures and other important components to travel through them. Though single-lumen tubing can be useful for a number of simple applications, multiple-lumen tubing cuts down on the number of tubes required in tight, constricting spaces for more steady operation.
Multi-lumen tubing has become more complex alongside associated medical devices. Newer multi-lumen tubing may contain various lumen sizes within a single shaft, which makes concentricity of each lumen more difficult to achieve along with the appropriate wall thickness.
In micro-catheters, wall thickness becomes even more paramount. Micro-catheter designs require thin-wall thickness that can maintain accurate pressure and flow mechanics. A balance must be maintained between wall thickness specifications that can meet pressure testing, tolerances; and manufacturing repeatability to meet requirements.
Incorporating co-polymers of silicone and polyurethane delivers long-term biological stability and flexibility along with thin-wall thickness, implant-grade long-term biostability, lubricity and hemostability. The copolymer can also be used for encapsulating electronics or sensors, or along a shaft assembly with thin-wall coating capabilities suited to microcomponents along with microcatheter shafts and delivery devices.
Whether they serve a function outside a device, inside a device or inside a patient, production and selection of tubing is a critical part of medical design.
