Kingston Speech Valve

A speech valve made from zirconia could improve the performance of such devices for laryngectomy patients, prolonging the valve’s life by more than 15 months.

Researchers at Avoco Medical, a spinout company of Hull University, UK, say that existing speech valves made from silicone elastomers typically need to be replaced every three months. Team member Professor Michael Fagan explains that, ‘Silicone elastomers are soft, allowing the biofilm to attach to them and ingress into them. The biofilm growth is the major cause of failure’.

This has led to the invention of the Kingston Speech Valve (KSV), which is sponsored by the UK’s Department of Health.

The working parts of the KSV are composed of zirconia in order to combat the build-up of biofilm.

Fagan, explains that, ‘Since the material is highly polished and very hard, it does not allow the biofilm to attach to the material. Any material that does stick and builds up on the surface is just blown off during the use of the speech valve’.

The device also uses a silicone sleeve around the zirconia components, which acts ‘as a soft interface between the valve and the soft tissues of the throat’.

According to Fagan, the technology works from a closed position, ‘preventing solid and liquid from entering the trachea. It opens when there is sufficient air pressure, allowing air to pass from the trachea into the oesophagus and out of the mouth to create speech’.

He adds that the KSV uses ‘hard materials rather than soft ones as in existing valves, and therefore does not use a flaptype system’. The device is accompanied by a patent-pending multifunctional technology for the insertion and removal of the speech valve.

The KSV has undergone in vitro tests in the Medical Engineering Laboratory, at the University, outlines Project Engineer Dr Jean- Marie Lamvohee. ‘The results so far have shown that the speech valve meets the design specifications and is safe to be used in patients’. Pilot clinical trials are to go ahead once regulatory approval has been obtained. Partners to manufacture the device at commercial volumes have been established.

The KSV will, however, cost approximately three times the price of available products. Fagan explains, ‘Existing valves are generally manufactured from just one material using a moulding technique. The KSV is made up of several components requiring some complex manufacturing and assembly techniques’ he says. Lamvohee adds that, ‘each valve should last more than three times longer than existing valves and offers healthcare providers a significant saving in terms of the clinical time required for valve replacement’.

Dr David Farrar, Science Manager of Biomaterials at Smith & Nephew Research Centre in York, UK, says that his initial impression of zirconia’s use is that it is, ‘biocompatible and very hard wearing, which are useful attributes in this application.’

He adds that he is, ‘interested and intrigued by the group’s claims that it resists biofilm formation, as biofilm is a major challenge for biomaterials. I am not aware that any material has truly solved this problem, although the smooth surface achievable by zirconia may be an advantage’.  

Further information  

www.avocomedical.com