This incredible ‘spongy’ implant repairs spinal injuries

16 Mar 2016

Spinal surgeons are soon to welcome a new, dramatic tool into their armoury, with a spongy polymer that fills the space around damaged (or removed) vertebrae to encourage regrowth.

While investigating metastatic spinal tumors, researchers from the Mayo Clinic have invented a strange, dehydrated sponge that could dramatically improve patients’ recovery.

Modern techniques to treat spinal tumors involve the removal of chunks of spinal bone and often the adjacent intervertebral discs, too. Filling this space is a tricky task both physically and economically.

From the front or from the rear

Traditionally, surgeons would go in through the chest cavity, building a metal cage or bone graft in place to allow regrowth. The better option is an incision from behind, but that leaves surgeons only enough room to insert titanium implants. These are expensive. Titanium is expensive.

Looking at this problem, PhD student Lichun Lu and a team of researchers looked at a way of installing a small device that could grow with the human body, eventually landing on a dehydrated spongy structure built to absorb nutrients in the body, growing to fill the space where bone has been removed.

Acting as a bone graft, it’s essentially a biodegradable (dissolvable) structure or scaffold, which when in place allows bone to grow in and around it after surgery.

Time against us

The researchers created a hollow hydrophilic cage that could then be filled with stabilising materials, as well as therapeutics.

“When we designed this expandable tube, we wanted to be able to control the size of the graft so it would fit into the exact space left behind after removing the tumour,” Lu said. An added complication was that the researchers also needed to manage the speed with which the cage expands. If it was too quick it would leave surgeons very little time to put it in place.

“By modulating the molecular weight and charge of the polymer, we are able to tune the material’s properties,” he said, with clinical trials planned in the next few years.

Everybody is at it

Elsewhere, Australian researchers recently installed the first-ever 3D-printed prosthetic during spinal surgery. We’ve even seen 3D-printing pens used to repair knee injuries.

So with the power of this decade’s primary innovator (3D printing) and hundreds of years of problem-solving medical practice combining, spinal injuries – or bone ailments on the whole – are amid a revolution.

That, mini human brains for drug testing and the dawn of bioengineered hearts means immortality might only be a few dozen discoveries away!

Lu and his associates research will be presented at a meeting of the American Chemical Society.

Main spinal injury image via Shutterstock

Gordon Hunt was a journalist with Silicon Republic