Implant To Correct Curvature Of The Spine

Scientists are developing a new implant to correct an abnormal curvature of the spine that affects up to four children in every thousand.

Unlike existing corrective techniques the device could be fitted to relatively young kids and "grows" with the patient.
It uses a hydraulic piston to apply a force between two points along the spine - gradually mending the bend, reports New Scientist.

The condition is called scoliosis where the spine veers to the side and becomes twisted often pulling the rib cage with it so the shoulder blade sticks out.
It gets worse with age and is more common in girls who account for eight out of 10 cases. There's also a genetic link with 25 per cent of sufferers having a relative with spinal curvature.
The traditional treatment for scoliosis is a back brace or in more extreme cases surgery to graft sections of bone or metal rods onto the spine to help straighten it.
But this "spinal fusion" surgery usually cannot be done until a child is almost fully grown - by which time the symptoms are already advanced.

The technique has other drawbacks as it restricts movement and can cause surrounding muscles and ligaments to waste away. Dr Jose Alvarez Canal, a mechanical engineer who has been working on the new implant at NADAR Computerized Medical Systems in Langreo, Spain, said: "Vertebral fusion drastically weakens the strength of the skeleton."
He says controllable machines are needed that progressively manipulate the spine over time.

The new implant - developed in collaboration with spine experts from France - reduces the force of the hydraulic piston as the child grows. To correct this doctors need to top up the pressure.

The NADAR device is designed to allow some free movement of the spine - some of which it harnesses to pump hydraulic fluid from a low-pressure reserve within the device into a high-pressure reservoir. When adjustment is needed the doctors use wireless telemetry to open a valve that releases fluid from the reservoir into the piston. The device, described in the journal Mechatronics, is removed completely once the spine is straight reducing the risk of complications. Dr Canal says tests on sheep have been very promising, but it will be at least three years before it's ready to be tried in humans.