Today, we would like to give you a short insight into the world of 3D printed bones. Bones, mostly in the form of a skeleton, have become a piece of art since the hype on Mexican art, especially the Day of the Dead (día de Muertos), spread all over the world. But what are you associating with the word bones? Immediately 3D printing? When I read the word first, it reminded me of the American TV show Bones, where the forensic anthropologist Temperance Brennan (called Bones) is reading clues from victims’ bones. Actually, 3D printing has been starting to support forensic departments since a while ago. With the great progress in tissue printing, 3D printed bones are getting more important in the field of medicine, here primarily in the field of implants, cancer and fractures. Interested to read more? Come on!
Forensics and Bioarchaeology
Bones seem to be very robust and hard to destroy, but they are more than this: they can tell forensic anthropologists stories about the life of their owners and in most cases about the cause of death and the murder weapon. But the stories bones tell can be destroyed easily. Forensic anthropologists are becoming more and more interested in 3D scanning and printing, as the scanners and 3D printers which are on the market now are finally affordable and accurate enough to be used in labs. The printed bones can be presented to the police and can be introduced to a jury as a physical evidence now. A few weeks ago a 3D printed bone was used in a homicide case in the UK without compromising the case. But how did it work before?
In former days, photographs were presented to the police and the court to give proof to a theory. Today, authorities start to hand over 3D printed bones to court or jury, as, on the one hand, bones are three-dimensional objects and photographs simply do not accurately capture the evidence at hand, and on the other hand, the presentation of human remains might be shocking for some individuals, which could lead to prejudicing the jury. Additionally, the forensic expert David Errickson points out in his article (Forensic Radiology and Imaging) that “handing bones in courtroom environments could cause bone degradation, which could damage the very forensic evidence of interest.”
How does it work today?
- the fragment is digitally scanned (WMG X-rayed pieces of bone from a range of angles, collating thousands of images that allows detectives, forensic experts to examine the evidence in remarkable depth.)
- with the help of a software bone parts can be easily combined, e.g. found in different places
- afterwards potential murder weapons will be 3D scanned
- the bones and the murder weapon will be compared
- the bones will be printed in 3D to show in court
3D printing is not only in forensics a new thing, it is getting a big thing in medicine, too. Tissue printing is the key word that seems to revolutionize regenerative medicine. As tissue printing is quite complex, we will dedicate another blog article just on this technique. Here, we give you representative examples of how 3D printing has improved medicine in the field of cancer care, implants, and orthopedics.
In former days, bone models were rarely made for patients’ cases because they were very expensive and it took weeks to complete them. In contrast, 3D printed models cost around $150, they are printed within a week and can be shipped worldwide to prepare complex surgeries. More and more hospitals start to use 3D printed bones not only for the preparation of the surgery, but as illustrative models for surgeons in training and the patient itself.
3D printing of bone substitute implants was first announced in 2012 when an 83-year-old lady got the first 3D printed jaw implant in Belgium. The women needed a replacement due to a seriously infected jaw bone. The replacement was printed with the SLM (Selective Laser Melting) technology and titanium powder. (On metal printing read more here).
Bone replacements are often needed in orthopedics or cancer care, as the disease has destroyed bones. Here, either 3D printed bone substitute implants, e.g. made of calcium phosphate, and bioactive glasses, or a cortex cast, which will support the healing of a fracture, for example, can be a solution. The University of Nottingham (Prof. Kevin Shakeshaff) is working among others (MIT, Harvard) in the field of custom made body parts and bones. They see customized implants for bone replacement as an outstanding help for surgeons to remodel, for example, maxillofacial (face, jaw) or craniofacial defects (face and skull). The technique is not the tricky thing, it’s the material. The researcher can use common 3D printing techniques, but have to find a special material composition that needs to have bio resorption properties (such as β-tricalcium phosphate (TCP) or bioactive glass). More research is needed here.
The Bone ‘Makers‘
Have you ever thought about growing your own bones? Possibly not, if you hadn’t been in a situation where you would actually need a bone implant. “Growing” bones is of course not as easy as, let’s say, growing carrots. Bones are not just sowed and afterwards harvested. There are approximately 900,000 bone-related surgeries per year and patients get either cadaver bones, artificial substitutions or bones cut out of their own body. To “grow” people’s own bones is a disruptive technology and can change the treatment of bone diseases.
There are some startups and universities worldwide, which are really curious in making bones grow. Among them is a promising New York-based startup called EpiBone, which focuses on bone reconstruction and makes bones grow from people’s own stem cells. EpiBone are working on head and face bones but potentially can engineer all kinds of bone, ligament and cartilage. This kind of bone can be described as a renewable source, which fits the body’s individual anatomical shape perfectly and can grow with the body. The company announced that it will start testing its bones in human trials hopefully within the next 3 years. This would be a great relief for everybody, who is in need of a bone implant due to a defect repair, a simplified surgical procedure, an improved bone formation and regeneration. This method of bone printing will shorten recovery times, without the complications of foreign body implantation.
EpiBone uses a bioreactor platform technology for engineering custom-designed autogenetic bone grafts. The researchers have been working on this platform for 20 years and gained experience with tissue engineering in the orthopedic field. Research has shown that bioreactor cultivation of human stem cells in a bone producing scaffold supports cell survival, differentiation, maturation and deposition of bone matrix.
But how does bone printing with your own stem cells actually work?
The bioreactor can be compared to a fish tank, which keeps the scaffold moist and tells the stem cells to head for bone cells. The process can be divided into the following steps:
- first, data from CT scans is needed
- from the data, anatomically-shaped scaffolds are fabricated
- the scaffold is seeded with stem cells derived from the patient’s own tissue
- placement of the seeded scaffold in the bioreactor system for pre-conditioning and maturation of the bone.
- bone ready for implantation
It takes 5 weeks from the CT scan to the final bone.
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