3D printing has become a highly versatile and progressively cost-effective technology, permeating a variety of fields, including healthcare. A 3D printer is made up of the printing machine itself, the software that contains the design and instructions for printing and finally, the ink.
Uganda: A spark from an oil lamp set fire to Veronica's sleeping mat on the ground when she was six months old; she sustained burns over much of her body and lost one arm. With her family unable to care for her, Veronica was taken in by The Giving Circle, which gave her a home at one of its orphanages. A volunteer for e-NABLE said that they made three different sized prosthetic arms because Veronica will grow and they wanted to make sure she would have a prosthetic that was a perfect fit. Lourds Lane, Founder of The SuperYou FUNdation was also involved. She said: “Meet our little superhero, Veronica. When I met her, she was a bit shy, at least with me. But when I sat with her and the other orphans at the Koi Koi House, as part of the work of my non-profit, all the children, especially Veronica, began to show their true colours. Using art and music, I began to teach the children how to find their inner superhero selves.” Veronica chose to name her inner superhero ‘Super Healer’ (image courtesy e-NABLE)
The ink used is arguably the most important part of a 3D printer as it becomes the object that is to be created and, as such, is the element that provides the great versatility of these machines. The ink can be molten glass that fashions glass art, steel, titanium, nylon, photopolymers, plastic and even food. 3D printers used in healthcare, often called bioprinters, can use a different kind of ink consisting of organic materials whose composition varies depending on the desired end product.
In the medical field, 3D printers have expanded fields of research, which ideally would result in the printing of organs for transplant, eliminating the need for a donor. Organs are incredibly complex systems however, and the ability to create a functioning heart, liver or lung is still far away.
Creating prostheses or devices that perfectly match the patient’s needs on site and in a short period of time however, is a goal that is near realisation. Prostheses have been created cheaply and quickly using 3D printers, although it is not yet standard practice. While prostheses are a solution for those who have lost their limbs, the ultimate goal would be to prevent the loss of limbs as much as possible. Some amputations are necessary when there is grievous injury to the limb, including down to the bone, and while bones are generally very regenerative tissues, major bone loss is very difficult to treat.
Trauma to the limbs that results in bone or limb loss can be a result of stepping on a mine, IEDs, vehicular accidents and shotgun injuries. Current treatments for such patients comes down to amputation and bone grafts if the injury is less severe. Amputation is considered only when it is clear a limb cannot be saved or its presence is risking the life of the patient.
Patients who can heal with a bone graft must cope with the associated risks. Autografts are considered optimal because the source graft comes from the patient him or herself. This however, means that the patient must undergo two surgeries; one to harvest the autograft, which then needs to be shaped, and one to insert it into place at the injury site and these processes involve doubled risk of infection and pain.
The other option is an allograft, which can be taken from a matching donor or created synthetically. Donor allografts are difficult to obtain and a lot of money and effort must be expended to do so, whereas synthetic grafts might be rejected and don’t have the same adaptability and bioactivity as bone.
Cross-section of a 3-D printed adult human femur from a Northwestern University Engineering research team led by Ramille N Shah (photo: Northwestern University)
3D printing presents an alternative to bone grafts. Previous research involved creating the bones themselves using hydroxyapatite and other minerals. However, this was not without difficulty owing to the secondary function of bones wherein they produce blood cells in the marrow – a difficult process to reproduce. Instead, new techniques are focusing on creating a scaffold composed of bone powder and polycaprolactone and layering it in stem cells and growth hormones.
The growth hormones are meant to promote differentiation of the stem cells and, once implanted, these will continue to grow and create bone using the scaffold as a foundation and the host’s system to revascularise the growing tissue and cause it to harden. These scaffolds are biodegradable and as time passes and tissue growth is stimulated, the scaffold will break down to leave behind only the regenerated bone tissue.
The rapid creation of perfectly tailored scaffolds that will support the injury and stimulate healing and regeneration of the bone would provide a fast, relatively inexpensive and, if effective, a lifelong solution for injuries with major damage to bone. In this way, 3D printing could enable swift construction of products tailored to the specific individual’s injury and needs on site.
For those who are born with limb reduction defects or people who have had a prior amputation, 3D-printing provides an exciting and affordable solution.
The ability to create 3D-printable prosthetics is changing the way physicians and patients approach prosthetics. In recent years physicians and engineers have been able to develop wearable, comfortable, and customised prosthetics for a wide range of people. From young children to adults, 3D printing makes it easy and fast for physicians to provide functional alternatives to those who have experienced limb loss owing to injury or birth defect. These prosthetics are also less expensive and quicker to make than traditional options, costing patients around $50 and can be available within a day compared to commercially available prosthetics, which start around $5,000.
Groups of engineers, designers, physicians, amputees and the public have come together in many places to make 3D printable prosthetics a reality. One group, e-NABLE, is a dedicated network of individuals from around the world who are working towards making these printable prosthetics available to people in need. Using the latest technology these printable prosthetics are highly customisable and ‘patient-specific’, fitted to each individual based on features of their unique anatomy (FDA). A spokesperson for the global network of volunteers told CRJ: “While these devices have just a simple basic grasp and can not lift much weight, it seems that one of the most treasured function - is a self confidence boost in the recipient who gets it. There is something to be said for how it makes them feel versus function alone. There are many who opt for trying an e-NABLE device over their traditional claw and hook devices, simply because it makes them feel like they blend in more.”
Researchers at MIT’s Lincoln Laboratory's Technology Office Innovation Laboratory (TOIL) have been working to improve the comfort and functionality of these prosthetics. Using Magnetic Resonance imaging (MRI) and quantitative measurements of residual limbs a group at MIT created a 3D printed socket that allows for optimal comfort. In order to improve functionality, designers have added nonelectoral temperature and tactile feedback to aid finger motion. A tactile component would greatly improve patient experience by allowing them to feel pressure through flexible tubing, running from the fingertips of the prosthetic to the forearm of the patient.
In addition to patient specificity, 3D printed prosthetics are a favourable alternative to conventional prosthetics in children. Since children tend to outgrow a prosthetic limb about once a year, families will save money replacing a 3D printed prosthetic rather than a conventional one. The stretchable and expandable features of these new prosthetics also make them a great option of young children or adolescents.
Currently only external hand prosthetics are available and recognized by the FDA; but the future of 3D printing of more prosthetics, including arm, foot, and leg look promising. Investigators are also looking into the application of 3D printing in manufacturing living organs such as liver, heart, or lungs, but this research is still very new.
3D Printing may also have found a large market in the domain of surgery as a training tool for surgical residents and practicing physicians. When preparing for a procedure, many surgeons will mentally rehearse their strategy. Although surgery is significantly skill-based, surgeons will often be confronted with novel procedures that they are not comfortably familiar with. In such instances, they have to rely on the intuitional knowledge they have cultivated from performing procedures in the past and in observing other surgeries.
Dr Peter Weinstock, an Intensive Care Unit physician at Boston Children's Hospital, points out the incredible reality that there is no physical run-through of a surgery prior to ‘game time’. Yet, similar high-stakes industries ranging from nuclear power to airline run through simulations that help workers prepare for worst-case scenarios. According to Dr Weinstock, it is time that surgeons and surgical teams also have the opportunity to refine their skills by practising in a realistic context of their trade.
According to a report by Kahol et al, surgeons can improve their performance via a “preoperative warm-up.” Participants in this study were asked to warm-up using a 15 to 20 minute surgical simulation using a FLS Training Box. After the standardised exercises had been repeated following the warm up, a 33 per cent reduction in errors was demonstrated. The time of performance was also shortened, while gesture proficiency, smoothness of hand and tool movement all increased.
3D printing can be an ideal training tool that replaces the simulation in this context. It provides surgeons the opportunity to perform a designated operation as many times as they’d like on a lifelike model of their actual patient, prior to entering the operating room. Dr Weinstock speaks fondly of collaboration between Hollywood and medicine, that has allowed them to reproduce patients so as to improve relevant training techniques for surgeons and ultimately enhance their performance.
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- 3D Printing Bones
- Hyperelastic “bone”: A highly versatile, growth factor–free, osteo regenerative, scalable, and surgically friendly biomaterial
- The Search for Better Bone Replacement: 3-D Printed Bone with Just the Right Mix of Ingredients
- Three-Dimensional Printing of Bone Extracellular Matrix for Craniofacial Regeneration
- Biocompatibility of ceramic scaffolds for bone replacement made by 3D printing
- Hydroxyapatite scaffolds for bone tissue engineering made by 3D printing
- 3D-Printed Bones Could Replace Bone Donations in Treating Landmine Victims
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- A Brief Preop Warm-Up May Improve Surgical Skills
- TedTalk by Peter Weinstock