A British surgeon has used the latest 3D-printing techniques to create a new pelvis for a man who had lost half his original one to cancer.
The patient is now able to walk with the aid of a stick after the transplant of the first pelvis of its kind.
Craig Gerrand, a consultant orthopaedic surgeon at Newcastle upon Tyne Hospitals NHS Trust, used the procedure on a patient in his 60s who had to have half his pelvis removed to stop the spread of bone cancer.
Scans allowed his team to measure exactly how much bone would be removed. A replacement to fill the gap was then created on a 3D printer by laying down successive layers of titanium powder fused together by laser. The titanium pelvis was coated with a mineral into which the remaining bone could grow and a standard hip replacement was fitted into the new socket.
The patient suffered from a rare bone cancer called chondrosarcoma.
“The cancer affected virtually the whole right side of the pelvis [the ring of bones that connect the base of the spine to the thigh],” says Mr Gerrand. “Since this cancer does not respond to drugs or radiotherapy, the only option to stop it spreading was to remove half of the pelvis.”
Standard implants, made by hand, do not always fit well – and in this case, so much bone needed removing that nothing would be left to which such an implant could be attached, he says. But without a reconstruction, the patient’s leg would be left “hanging”, unattached to the spine, and shorter than the other.
Which was why the surgeon offered him an extraordinary reconstructive innovation: to 3D-print half a pelvis, designed to fit precisely into the space left by surgery. There were, of course, risks – of such an implant failing to fit, or fracturing. “The patient was fully informed of these and decided to go ahead.”
Meticulous planning was needed if the operation was to have a chance of success. The first step was to fuse CT and MRI scans of the pelvis to calculate precisely how much bone would be removed, and the dimensions of the space that would be left behind. The data were used by a British company Stanmore Implants, to 3D-print a bespoke model of a half-pelvis, with exactly the same shape and dimensions as the bone lost by the patient. The 3D process, also called additive layer manufacturing, involves gradually building a three-dimensional shape by laying down successive, fine layers of titanium powder, fused together by laser.