A prosthetic mesh implant that allows bone, blood vessels and collagen to grow around it like plants on a garden trellis promises to improve recovery time and minimise infection rates for patients needing a bone replacement.
The porous microscaffolding structure, which was designed by Sandia National Laboratories and the University of Illinois, is stronger than bone and can be used in areas of the body such as the skull and spine.
Sandia prosthetic devices are built using hydroxyapatite, a ceramic material with the same mineral content as bone. ‘This means it is not rejected by the body,’ said Sandia scientist Joe Cesarano, whose team developed the implant technique.
The implants can be manufactured to fit a damaged area prior to surgery. Using CAT-scan images of the area, surgeons and technicians recreate an image of the missing bone.
A prosthetic replacement is then made using a process called Robocasting, patented by Sandia and originally used to fashion ceramic defence components that could not be made by moulding or machining.
Robocasting deposits slivers of liquefied ceramic paste, 500 microns thick, across each other, creating a lattice to form shapes dictated by a controlling computer. The final design even includes a groove for nerves to grow in.
Using prosthetic implants to replace diseased bone results in a much shorter surgery time than the standard process of grafting-in bone. Bone for grafting is cut from other areas of the patient’s body (to reduce the risk of infection), usually from the pelvis, before being sawn and drilled into the correct shape in the operating room.
This process takes up to an hour, increasing the patient’s intake of anaesthetic and the risk of complications. Afterwards patients must endure the pain of a healing pelvis as well as the pain of the healing area the bone has been grafted into, and both areas run the risk of becoming infected.