Here we run through just nine of the most noteworthy ways 3D printing has reinvented medical science.
1. Blood vessels
While the manufacture of artificial tissue was a significant breakthrough in medical sciences, these regenerative projects were limited by the lack of a key component: blood vessels.
In 2014, however, researchers from Harvard effectively created tissue interlaced with blood vessel-like structures by using a gelatine-based ink to 3D print hollow vessels, as small as 75 micrometers in diameters, within a mesh of printed cells.
A year later, researchers from Lawrence Livermore national Laboratory shared their groundbreaking success with 3D printing in constructing blood vessels. These vessels, which were printed using a “bio-ink” in an environment that was also made of biomaterial, were able to assemble on their own over time, ultimately forming a self-sustaining network that mimics the circulatory system in the human body.
These bio-printed vessels are especially useful for patients with vascular disease or malfunctioning blood vessels who currently depend on grafts from tissue donors.
As recently as last month, researchers from Northwestern University in Illinois developed a white ink made from a blend of hydroxyapatite, a mineral naturally found in bones, and a polymer which can be 3D-printed into bone implants.
Unlike the brittle bone grafts which are usually taken from other anatomical sites, this affordable elastic biomaterial is more flexible, can be easily moulded and will not fracture when handled during remodelling.
Once implanted, the “hyper-elastic bone” is easily infiltrated by blood vessels, integrates quickly with the surrounding tissue and gradually allows real bone tissue to regenerate due to its matrix and mineral content that strongly mimics that of natural bone.
According to the researchers, this breakthrough can help orthopaedic and reconstructive surgeons with a multitude of skeletal problems, from simple fractures to delicate spinal repairs and even reconstructive surgery requiring implants.
3. Prosthetic limbs
A large population across the globe are living with limb loss, due to various factors such as trauma or vascular diseases like diabetes or peripheral arterial disease.
While modern custom-made prosthetics have allowed these patients to regain physical function and independence in activities of daily living, they are often costly as they require careful maintenance and regular reviews for fitting.
Fortunately, 3D scanning and printing has allowed for faster construction of better quality artificial limbs compared to the traditional plaster cast method – and for a more affordable price. Using the technology, prosthetics can also be quickly repaired or remodelled which is especially useful since the human body often changes.
The use of 3D printing in customising prosthetics is increasing. With the World Health Organisation (WHO) approximating that 30 million people from low-income regions are in need of prosthetic limbs, 3D printing is hoped to be able to revolutionise the orthotics field.
4. Medical models
In January, a nine-year-old girl with a congenital heart condition in Singapore underwent a successful cardiac operation, which was less invasive, thanks to a 3D printed heart model.
Before performing the complex surgery, the surgeons constructed a “real size” 3D heart model based on the child’s MRI scans to attain a better spatial visualisation of the organ and to study the correction that needed to be performed.
The models can also be used for surgical training and to improve understanding of anatomy.
In May, surgeons from the UK used 3D printing to make a replica of a patient’s prostate to assist in the removal of a tumour. The remarkably accurate model helped surgeons perform the surgery with precision and minimised the risk of impotence and incontinence.
5. Maxillofacial reconstruction
Previously, facial reconstructive surgeries were invasive and involved autografts from patient’s own skin and bone, which were difficult to shape and implant and posed high risks of infection. In 2014, however, the FDA approved the first 3D-printed polymer facial reconstruction implant, of which are individualised to patients’ needs and are highly effective as well as economical.
The same year, a skull transplant was performed on a patient by surgeons from the Netherlands, using a 3D piece that was specifically printed to fit her. The patient, who suffered from a condition which increased the thickness of her bone structure, had increased intracranial pressure and was suffering from visual and basic motor coordination impairment.
Fortunately, the operation was a success and she regained her vision completely after the transplant.
6. Synthetic skin
While deep burns and other trauma can be treated with skin grafts harvested from other sites of the body, in instances where there are extensive wounds or in paediatric patients, there may not be enough healthy skin to harvest.
Thus, a team of researchers from the Institute of Regenerative Medicine at Wake Forest University in North Carolina are developing a system to enable printing of skin directly onto burn wounds.
First, the bio-printer scans the wound site to calculate the depth and area of the wound and ascertain the layers of skin needed to be printed on the site. The skin is then printed with “ink” that is made from different skin cells.
Their efforts, which were motivated by the large number of injuries by soldiers in Iraq and Afghanistan, can help treat patients with skin diseases or trauma such as burns that can be cause severe pain or worse, death.
7. Diagnostic tools
Health professionals encourage individuals with cancer risk factors to undergo screening, as early detection and intervention often yields better prognoses. Medical researchers have been developing a diagnostic tool which can detect even early stages of cancer using a small blood sample – using 3D printing.
According to researchers, the technology, which focuses on microRNA detection in the blood to identify cancer in patients, would be much more cost-effective and yield faster results compared to current diagnostic tools available.
While many health experts find it hard to believe that cancer can be detected at a molecular level from a blood test, researchers say that the clinical validation studies show promising results, and diagnostic tests based on microRNAs could be used not only for cancers, but also for other diseases.
8. Medical equipment
An associate engineering professor from the University of Wisconsin-Milwaukee has recently modelled an umbilical cord clamp that he constructed with 3D printing.
But this is not the first time medical equipment was printed using the 3D technology. To date, the US Food and Drug Administration (FDA) have approved over 85 3D printed medical devices, including implants, prosthetics and surgical instruments.
In 2010, humanitarian workers at Haiti were already using 3D printing to construct umbilical cord clamps on demand, proving that smart use of this innovation can be live-saving especially in low-income countries or during disasters.
9. 3D ultrasounds
While most couples who are expecting a child get to the experience the joy of seeing their babies for the first time from an ultrasound scan, parents to-be who are visually-impaired are unable to share the same experience.
Fortunately for 3D scanning and printing, these antenatal “ultrasounds” can now be printed as physical moulds. Although this may not necessarily serve as a medical breakthrough, the use of this technology can no doubt help those with visual impairments “see” their babies’ ultrasounds and experience the little things that the rest of us usually take for granted. MIMS
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