The engineers are using machines to test implants for both the lower back, or lumbar region of the spine, and the cervical spine, or the neck region. Implants are attached to spines from cadavers, and then the spines are tested in the Purdue Spine Simulator, a hydraulic machine that recreates the spine's natural movements and shows how the implants stand up to everyday activities.

One of the machines designed by the Purdue engineers is used specifically to test implants for the cervical spine.

"There is much more movement in the cervical spine than in the lumbar portion, so what we are primarily testing with this machine is how well implants will stand up to wear over a period of about ten years," said Shreekant Gayakar, a graduate student in mechanical engineering. "We are replicating the range of motions seen in the human neck."

The machine tests ball-and-socket-like implants such as the ones inserted during surgeries to replace damaged parts in the cervical spine.

"In order for implants to be approved by the Food and Drug Administration, it has to be shown that they can last ten million cycles, or ten million movements, which translates into about ten years of living," Hillberry said. "Our goal is to complete ten million cycles over a four-month period."

"Future designs may ultimately be used in conjunction with total disk replacements, allowing the restoration of function at any vertebral level in the spine, much like total hip and total knee replacement currently achieve, "said Jorge Ochoa, vice president of research and development.

"These implants are tricky to insert because major arteries are located along the spine," Hillberry said. "If an implant is not designed to fit precisely into a particular person's spine, the spine can actually eject it during surgery, causing the artificial part to sever a major blood vessel that runs along the spine.

MEDICA.de; Source: Purdue University