Unravelling Polymers

The Definitive Blog on Polymers by Poly Fluoro Ltd.

PTFE Amplatz Sheaths - Specialised Tubing for Medical Applications

The versatility of PTFE as a material has been explored many times. The applications of this miracle fluoroplastic range from bearings to seals to automotive components to heavy insulation. However, it is PTFE’s use in medical devices and equipment that is truly obscure and worthy of exploration.

PTFE properties for Medical Use

It is commonly known that PTFE is highly inert. This property allows PTFE to be one of the few materials that can remain in the human body for extended periods of time with no adverse effects. In addition to the inert properties of the final material, PTFE resins are, by default, FDA approved – meaning that if processed correctly, PTFE can be used in food and medical applications without too much additional documentation. Obviously, a medical device manufacturer would need to preform their own tests and validations to the material before employing it in their application, but the likelihood of PTFE failing any such tests is low. Finally, PTFE is processed at such a high temperature that, if handled properly, it is completely sterilized once fully processed.

Despite this, medical tubing usually calls for a clean room set up in order to ensure that the final products are suitable for medical use.

PTFE Amplatz Sheaths

Once such specialised application of PTFE in the medical space is the use of amplatz sheaths. These sheaths are used in medical devices to allow the smooth passage of surgical instruments into the body. The sheaths are designed to be probed into the body and form a channel through which instruments can be passed. In applications such as urology, a polyurethane pipe will pass through the sheath and a guidewire will the pass through the polyurethane pipe. This telescopic arrangement allows the medical guidewire to move into the body with precision and without causing any abrasions within the body.

In other instances, balloons can be fitted to the end of the sheath (which usually has a tapered tip), and these can be blown up once in position by passing air through the sheath.

Most notably, this product has the following properties, beyond what PTFE would normally have:

  1. Radiopacity – a filling of barium sulphate or bismuth trioxide makes the tube visible to x-rays. PTFE is naturally invisible to x-rays so the filler arrests this property and allows the sheath to be detected as it is inserted into the body

  2. Stiffness – while most PTFE tubes are flexible and come in coils, amplatz sheaths are made stiffer and straighter to suit their application. The added stiffness also makes the PTFE tube kink-resistant, meaning it is safer to use

  3. Pigments – while pigmented tubes are not uncommon, amplatz sheaths are usually taken in dark-grey or blue pigments. The addition of pigments is useful for colour coding and also contributes to the stiffness of the material

  4. Tapered end – the tubes can be either tapered by thermoforming or simply cut at an angle, allowing them to better glide into the body

The development of amplatz sheaths has allowed Poly Fluoro to become the only company in India with the capability to manufacture these items indigenously. With a fully equipped set-up for extruding high-precision PTFE tubes, we are able to customize for size, colour, and radiopacity, giving us a unique position in an ever-growing, ever-evolving medical device market within which India is poised to become a vital player.

Read More

1. Expanded PTFE (ePTFE) Tube - Applications and Advantages

2. PTFE Lip Seals - Applications, Material Choice & Advantages

3. ePTFE Membranes - Application in high-end face masks

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