British and Russian surgeons rebuilding faces of children involved in accidents have used a new honeycombed polymeric implant. The material bonds with the bone without causing adverse reactions. The made-to-measure implants are light, tough, flexible and cheap, providing an excellent alternative to traditional titanium. They are easier to adjust and re-shape and give much more flexibility. These implants allow carrying out many more operations than before.

When a child is assessed for an operation at the St. Vladimir Children’s Hospital, Moscow, scientists use X-rays and tomography images to create a three-dimensional plastic cast of the damaged area. These solid biomodels, built by a high-tech process called laser stereolithography allow surgeons to plan operations with great precision before they even lift a scalpel. Having assessed how much bone needs to be removed, the scientists in Troitsk use stereolithography to make the individual PolyHap implants. The technique, which can be completed in a matter of hours, can be used to make the most intricate shapes that are then sent to the hospital. The outline of the implant is initially “drawn” by a laser beam, which leaves a very fine coating of polymer. This process is repeated hundreds of times until the model is complete.

Although the PolyHap implants have produced good results there is a possibility the implants might have to be replaced as the child grows and the bones develop. In order to make these ‘vanishing’ implants, a new Surface Selective Laser Sintering technique is being developed. This involves using a laser beam to melt just the polymer surface, leaving the bioactive inner section intact – a crucial factor in creating a biodegradable implant.

(The ‘PolyHap’ implants have been developed by teams led by Professor Steve Howdle in Nottingham and Dr. Vladimir Popov from the Institute of Laser and Information Technology in Troitsk, near Moscow, whose work is described in the current issue of Advanced Materials)