Erle Austin was facing a major problem. A child with a life-threatening condition would soon lie on his operating table.
The child's chest would be opened, his young heart momentarily stopped for the surgery to take place that may save him -- surgery that requires incisions to access and operate on the inside of the organ.
Heart stopped, incisions made, the surgeon then has to figure out what the problem is. He has a good idea based on two-dimensional scans produced prior to surgery, but the outside of the heart prevents him from seeing the inside. "If I went in and did surgery, took off the front of the heart and did irreparable damage, the child would not survive," says Erle Austin, a heart surgeon from Kosair Children's Hospital, Kentucky.
But what if he actually had an exact replica of that child's heart before he did that surgery?
That child made a full recovery. In fact he was home within four days and with a heart stable enough that no cardiac medication was required after the procedure.
In professional terms Austin achieved this by combining X-ray computed tomography, stereolithography CAD software and additive manufacturing equipment. But in easier terms? "I'm using 3D printing to help me understand a complicated heart," explains Austin, speaking at Maker Faire in Rome.
Austin was able to produce an exact 3D-printed replica of his child patient's heart before any operation took place. A CT scan conducted with X-rays allows him to take photographs of the heart in thin "layers". These layers are loaded into computer-aided design software developed by 3D Systems (notable in part for having musician and entrepreneur Will.i.am as its chief creative officer).
Then the resulting 3D image is fed into an experimental 3D printer developed by Makerbot Industries that takes 20 hours to print the complete heart out of a flexible thermoplastic called NinjaFlex, and it does so in three parts: the front, which prints in four hours; the centre, which takes twelve; and the back, which takes a further four.
Without risking irreparable damage, he took off the front of the heart and was able to study the internal structure of the organ and plan a procedure that resulted in the four-day hometime.
. "I can go through a small incision and work through that and do all of that surgery with a minimum amount of injury to the heart
[...] The child had an excellent recovery and was home after only four days and required no heart medicine."
It's a tremendously encouraging real-life story of how 3D printing can improve the efficacy and understanding of complex medical procedures. In the future, Austin suggested, such techniques could be helpful in the training of surgeons, as well as aiding the communication between cardiologists and surgeons.
The future of bioprinting
But looking to the future, advanced research could result in the creation of hybrid structures that pair synthetic materials with functional biological cells. Working prototypes of 3D-printed ears already exist, in fact. Michael McAlpine, from Princeton University (also speaking at Maker Faire), developed a technique that allowed a 3D printer to produce working ears from real cartilage cells, silicone and silver nanoparticles (Ag-NPs). "We're printing biological and electrical cells at the same time," he said. "These are real cartilage cells that can be cultured into real cartilage tissue," he added. "This ear can actually hear." "These ears can hear in [the human range of 20Hz-20kHz], but also into the megahertz and gigahertz ranges. We printed two ears and they could hear Beethoven."
To prove this, he played a recording of a symphony -- as recorded by the ears.
While functioning 3D-printed replacement ears are not yet viable for medical use, a number of uses for 3D-printed replicas of body parts, similar to the heart produced by Austin, exist.
British 3D printing company Replica 3DM, based in Wiltshire, recently provided twelve NHS Trust hospitals with manufacturing stations built by Stratasys to create replica hips for surgeons practicing hip replacement operations. These Stratasys stations can also produce implants to fill holes in the skull, as well as models required for rehearsing spinal operations.
In June 2012, an 83-year-old woman had her lower jaw replaced in the Netherlands. The transplant operation involved fitting her with a 3D-printed replacement and she was home within four days of surgery.
Elsewhere in the dental world, dentists have used X-ray modelling techniques similar to Austin's to accurately reproduce the jaws of patients seeking dental work. TDC Implant Centre, based on Harley Street in London, is one such practice that uses 3D-printed replicas of a person's jaw to more accurately plan dental implants. Two streets away reside married dentists Andrew Dawood and Susan Tanner, who offer treatment at their Dawood & Tanner practice also aided by 3D-printed dental replicas.
According to Cambridge-based market research firm IDTechEx, the medical and dental 3D printing industry will grow to be worth £500 million globally by 2025, up from £87 million in 2014.
This article was originally published by WIRED UK
