Urinary Catheters - Silicone versus Latex

Urinary Catheters - Silicone versus Latex

By Razia Sanwari

Urinary catheters are available in a large variety of sizes, materials and types. Selection of the kind of catheter to be used by the patient has to be made keeping in mind several factors such as medical need, expected period of use (whether short-term or long-term), personal choice and what are the risks involved in terms of infection.

You may buy the type of catheter as per its usage but the catheter material is essential and a lot of thought must be put into it because the wrong material type could be the cause of a number of health issues, such as urethral inflammation, allergies, phlebitis, encrustation, infection and deflation.

This concern has led to much laboratory study on the subject of the right type of material.

The Right Type

Catheter biocompatibility is important and will depend on the physical property of the instrument, its chemical nature as also whether the body’s reaction to the apparatus will impact its utility. Some materials are more biocompatible than others but there is no such thing as an ideal catheter.

Catheters are essentially available in three types of materials – silicone, latex rubber and polyvinyl chloride or PVC. The most commonly used are silicone and latex.

What is Silicone

Silicones are a group of inert, synthetic polymers with a chemical structure based on chains of alternate silicon and oxygen atoms. These compounds, which are rubber-like, have a variety of forms and uses.

What is Latex

The natural, milky-white, thick colloidal suspension containing hydrocarbon polymer is known as latex rubber. It is mostly obtained from the sap of the Para rubber tree called Hevea brasiliensis.

Silicone or Latex

Though there are a variety of silicone and latex catheters in the market, the preference of material has come under a lot of debate. There have been many discussions and several clinical studies conducted to understand the pros and cons of using a silicone catheter versus a latex one. And after all the research, experts have come to the conclusion that silicone may be the material of choice in demanding applications, particularly urinary catheterisation and especially if it is for long-term use.

The properties of silicone make it stand out versus a latex catheter. Silicone is typically resistant to chemical attack and insensitive to temperature changes. Characteristics include chemical and thermal stability, low surface tension and hydrophobicity. Silicone is one of the most thoroughly tested groups of biomaterials and recognized for its inherent biocompatibility and bio-durability.

Latex catheters, on the other hand, are found to be more prone to infection and hypersensitivity reactions. In comparison with silicone, latex catheters are believed to cause more injuries and increase irritation of the urinary mucosa. With silicone catheters, research says, there are less chances of incidence of trigonitis, meatitis and urethritis.

Encrustation and calcifications are seen to be significantly low in silicone catheters as compared to latex ones. Silicone ones also do not require catheter change as frequently as latex does.

Foley Catheters

Originally, Foley catheters were made of latex rubber but though cheap and flexible, latex is no longer preferred. Today, silicone-coated latex Foley catheters are used but, again, only for short-term. This is because the silicone layer on top tends to get damaged and the underlying latex is exposed, carrying the risks of allergies if exposed to the urothelium.

Without coating, latex rubber catheters are currently out of favour because they carry an increased chance of allergy risk plus provide discomfort due to the high surface friction. Additionally, latex tubing is more thickly and rapidly encrusted by mineral deposits. Some tests have also come up with the view that latex catheters may be more toxic than silicone ones.

In case of Foley catheters, silicone Foley catheters remain the preferred choice for long-term indwelling use though they may be a bit more expensive. They have a longer life and are more rigid in nature which is considered an advantage.