Researchers in Texas have developed a growing rod material that could potentially improve the success rate of childhood scoliosis treatment.
The super-elastic adaptive alloy can significantly reduce the complications from corrective surgeries, Texas A&M University said.
Children with early-onset scoliosis (a spine deformity that is present before 10 years of age) often need to have frequent surgical procedures to correct the curve in their spine. Surgeons implant metallic growing rods in the spine and expand them in bi-annual surgeries to keep up with the child´s growth. But as the body moves, the screws attaching the rods to the bone can become loose, increasing the chances of further surgery to keep the rod in place.
Dr. Ji Ma, Texas A&M Engineering Experiment Station assistant research scientist, and Dr. Ibrahim Karaman, Chevron Professor I and head of the Department of Materials Science and Engineering at Texas A&M University, have engineered a titanium shape memory alloy which they say is five times more flexible than any currently available growing rod implants.
According to the university, the new implant has stress-dependent elastic properties that adjust depending on the stress applied by the growing spine and allow natural movement of the body.
“By modifying these properties to fit the biomechanical environment of the bone, it is now possible to create a device that satisfies the seemingly conflicting requirements of rigidity and flexibility required in growing rods,” Dr. Ma said.
The adaptive alloy allows growing rods to bend at the ends and stay stiff in the middle, giving the necessary support to the spine. With reduced friction and stress, the patient´s natural movements stay flexible.
“This is not something you can do with all materials,” Dr. Ma added. “We preserve the strength and add flexibility to the implants without compromising the mechanical properties.”