Revolutionary bone reconstruction

Posted on 19 April 2022

The ‘Eiffel Tower’ custom 3D-printed truss cage reconstruction is a quick and efficient means of bone reconstruction with multiple benefits.

Bone loss is usually caused by trauma or infection. “In our country, road traffic accidents followed by gunshot injuries are the most common forms of trauma that cause bone loss,” says Dr Franz Birkholtz, an orthopaedic surgeon at the Institute of Orthopaedics and Rheumatology at Mediclinic Winelands Orthopaedic Hospital, who also practises at Mediclinic Midstream Hospital in Pretoria “This can result in a bone infection that needs to be cut out in order to clear, or bone tumours that are resected. In these cases, a big bone defect can necessitate reconstruction.”

When patients have tibial (shin) bone loss, reconstructing the bone can be a difficult and lengthy process.  Often, the bone is regrown with the help of an external fixator – a scaffold that can be worn on the outside of one’s hand, arm, foot, or leg to help keep bones in place so they can heal and grow.

Although this device is effective, it also takes a very long time to work – just one centimetre of bone takes roughly two months to regrow, Dr Birkholtz explains. He adds that in severe cases, reconstruction is sometimes not possible, which could possibly lead to amputation – always a last resort.

The custom 3D-printed truss cage reconstruction is a viable alternative. While Dr Birkholtz did not invent the procedure, he’s dubbed it the Eiffel Tower due to the shape of the cage. “It’s exciting because it gives us another salvage option which we can use in very difficult bone reconstruction cases,” he says. “This option that could also potentially reduce the group of those requiring amputation.”

So just how does the Eiffel Tower procedure work? “We conduct a CT scan of the injured limb and look at the shape of the bone that’s missing,” explains Dr Birkholtz. “We model that in three dimensions and in consultation with a biomedical engineer, and through the use of a 3D printer, we create a titanium truss cage that looks like the Eiffel Tower. The cage is then fixed to the surrounding bone and tissue. It’s basically a structure that takes over some of the function of the bone but because we pack the structure full of bone graft, it incorporates into the bone as well, becoming a permanent fixture and replacing that segment of bone that is missing.”

It’s a single procedure that solves a very complex problem in a single operation. “Other reconstructive options entail multiple procedures, operations and often long recovery time,” says Dr Birkholtz. “With this procedure, it takes six to eight weeks to hold weight again – with reasonable functionality in up to three months.”

Younger patients, non-smokers, and those with a healthy lifestyle who need to return to active life as soon as possible would get the most benefit out of the Eiffel Tower procedure, he adds. It has only been performed around a hundred times worldwide and a handful of times in South Africa over the last year and a half. Dr Birkholtz performed it for the first time in February 2022 on patient Zintle Dastile, after a car accident in September 2021 left her with two broken feet.

“My left side was more badly damaged than the right and I was left in an external fixator for six months,” Zintle says. The road to wellness would have been far longer had she not had the procedure. “If you go up to seven or eight centimetres, which is roughly how long Zintle’s damage was, you’re talking about more than a year during which she would have to have an external fixation cage around her leg,” explains Dr Birkholtz.

Zintle was thrilled when she heard that with the Eiffel Tower procedure, recovery time is significantly reduced. “That’s what has been most beneficial; it will allow me to really just get back to my life,” she says. “After the operation, I didn’t experience a lot of pain and best of all, I’m now able to bear weight on the left foot for the first time since the accident.” Zintle has weekly physiotherapy sessions and will need a different procedure for her right foot, but for now she’s grateful to be well on her way to recovery.

Published in Innovation