People with scoliosis have a curvature of the spine which usually develops during the growth spurt associated with puberty. To encourage the spine to grow straight, researchers from the Biomechanical Engineering department have developed an implant made of ‘smart’ metal: a combination of nickel and titanium.
The implant is a rod in the shape of a healthy spinal column. When it is cooled to around 0º C, the material becomes malleable whereupon it can be surgically attached to the patient's spine. When it is then heated briefly to approximately 40 º Celsius, the rod 'remembers' its former shape, thus straightening the spine.
The current rod has the disadvantage of effectively blocking motions of the instrumented section of the spine, reducing the total bending range. The researchers are therefore working on new versions which are not only flexible but will actually grow along with the patient. It will then no longer be necessary for surgeons to wait until the patient is fully grown before operating. Patients can be treated in early puberty and will retain the ability to bend normally.
The spinal column of a healthy person (left) and that of a patient with scoliosis.
Scoliosis implants in a model of a spinal column.