Micro Extrusion Contribute To Improvements In Medical Device Production, Patient Satisfaction

(Abstracted from an article by Bob Donohue, Navtar, a Tekni-Plex Company as published in published in medicalplasticsnews.com )

• Because of new technological developments, the definition of what constitutes microextrusion medical tubing has shifted.

• What was once called a microextrusion—typically a .015 inner diameter (ID) x .055 outer diameter (OD)—is now considered a standard extrusion. What used to be outlier dimensions are now considered common. In the past, these micro tubes were produced out of glass or, in the case of fluoropolymers, involved a secondary stretching operation to achieve the desired ID and OD.

• However, advances in plastic extrusion technology have changed the game. With minimally-invasive surgery becoming the wave of the future, microextrusion is allowing device manufacturers to provide products that otherwise would be difficult to achieve or expensive. The latest microextrusion tubing can now help OEMs develop complex devices that can provide therapies and treatments not previously possible for hard-toaccess extremities.

• Today’s new microextrusion definition is an ID size in the 35 microns (or .0014 inch) range, with very thin walls and extremely tight tolerances to meet the needs of newer invasive applications.

• Now that extrusion technology (both process and equipment) has caught up with the needs of the medical device industry, the latest microextrusion tubing can now be made in a one-step process from less expensive materials. The latest die designs, pressure transducers and high-end, inline, closed-loop controls, are a few of the many breakthroughs that have contributed to the development of thermoplastic microextrusion tubing.

• It is also important to point out that multilayer microextrusions in catheter applications is another main driver behind these developments. Being able to use microextrusion technology in combination with coextrusion technology adds many new options for OEMs. This can allow for a highly lubricious inner surface (for device insertion), along with steerable characteristics, by modifying the outer shell of the catheter. This technology allows for the use of radio opaque indicators to be incorporated into the design without affecting performance.

Precision provides significant performance, production impact

The ability to consistently manufacture microextrusion tubing in tight tolerances impacts both device production, as well as patient satisfaction. Catheters, for example, are typically tipformed and punched. When there are wide tolerance variances, the consumer experience will not be consistent each time he or she needs to catheterise themselves. One catheter tip may be painful upon insertion, while the next one might not be. Lack of consistency can result in consumer discomfort and stress in not knowing what the next usage experience will bring. When microextrusions are able to hold tight tolerances, then catheters are consistent and so is the consumer experience.

There are other applications, such as those where precise delivery is required, where tight tolerances also can have a positive impact. A good example to look at is a tube used for wound therapy. In this application, medication needs to be precisely administered to the wound area. Traditionally, liquid has been pushed through the tube to see how much volume was coming out. The tube would then be cut to get to the approximate correct volume. This less-thanprecise way of delivering medication was the workaround used to compensate for an ID that was not in tight tolerance. Conversely, when the tube consistently delivers tight tolerances through out its production run, then you are able to eliminate the delivery guesswork. It also benefits the device manufacturer by enabling higher throughput.

Potential applications

Potential applications for the latest microextrusion tubing are extensive and include both implantable devices and minimallyinvasive procedures. Possibilities include:

Heart leads. Connecting a pacemaker to the heart muscles.

Neurological. Treatments for stroke patients where micro stents need to be inserted into the vascular system to open capillaries to eliminate blockage.

Vascular. Below the knee procedures such as arterial drills to assist in blood flow below the knee that has been compromised by diabetes.

Catheters. Traditionally, heart catheterisation procedures use the femoral artery in the leg to access the body. Microextrusions would enable smaller devices to enter the brachial artery and aid in expanding smaller vessels that have potential blockage. With the capability to get into the smaller veins, as well as the larger ones, more of the heart is accessible.

In vitro fertilization. The new microextrusion technology can assist with a critical step of the in vitro fertilization process that enables the nucleus of the egg to be harvested more precisely.

Infant/paediatric care. The effectiveness of miniature devices, such as microcatheters that are engineered for the youngest among us, can also benefit from microextrusion tubing. Additional opportunities exist for treatments in the following areas: chemotherapy, auditory, ophthalmic, wound care, spinal therapies and others where smaller diameters and tight tolerances are necessary to achieve product objectives.

(https://www.medicalplasticsnews.com/medical-plasticsindustry-insights/how-microextrusion-medical-tubing-is-leadingto-new-procedur/, 22 AUGUST 2017 )