Web edition: March 11, 2013
Print edition: April 20, 2013; Vol.183 #8 (p. 12)
Surgeons have replaced 75 percent of a man’s skull with a custom-designed polymer cranium constructed with a 3-D printer. The surgery took place on March 4 and is the first U.S. case following the FDA’s approval of the implants last month. The patient’s reason for needing such extensive replacement surgery has not been revealed.
Similar surgeries may follow in other cases where sections of the skull are removed because the brain has swollen during a surgery or after an accident, says Scott DeFelice, president of Connecticut-based Oxford Performance Materials, the company that created the prosthetic.
Technicians used CT scans to get images of the part of the skull that needed replacing. Then, with computer software and input from surgeons, engineers designed the replacement part. A machine that uses lasers to fuse granules of material built the prosthetic layer by layer out of a special plastic called PEKK. While inert like titanium, PEKK is riddled on its surface with pocks and ridges that promote bone cell growth, DeFelice says.
Such implants have value as a brain-protecting material, says Jeremy Mao, a biomedical engineer and codirector of Columbia University’s center for craniofacial regeneration. But doctors will need to keep an eye out for long-term problems; The skull isn’t just a box for the brain but a complicated piece of anatomy linked to connective and soft tissues.