CAPE TOWN – 3D printing, or additive manufacturing, is considered among the most disruptive technologies of our time and offers immense possibilities for future development and is deemed to be at the forefront of the Fourth Industrial Revolution (4IR).
3D printing will effectively change the way we manufacture almost everything, whether it consists of metal, polymer, concrete or even human tissue.
The medical sector is one of the early adopters of 3D printing, and has over the years become one of the most vibrant areas for additive manufacturing. The rapid adoption rate can mainly be ascribed to the customisation and personalisation capabilities of 3D printing, as well as the continuous improvement of processes and materials to meet the high medical grade standards. 3D printing has proved itself as an invaluable tool both for medical education and in the operating theatre.
Surgical uses of 3D printing started already in the mid-1990s with anatomical modelling for bony reconstructive surgery. From this early work developed the personalised or patient-matched 3D printed orthopaedic metal implants. What makes these implants unique, is that it is printed with porous surface structures to facilitate osseointegration (the connection between living bone and the artificial implant).
In March 2014, surgeons in Swansea used 3D printed parts to rebuild the face of a motorcyclist who had been seriously injured in a road accident. Today, 3D printing technology is used to routinely manufacture stock items, such as hip and knee implants, personalised for specific patients.
Earlier this year, in a world first, South African surgeons used 3D printing to restore the hearing of a 35 year old man whose ear was severely damaged in a car crash. The surgeons reconstructed the broken bones of his middle ear by using 3D printed bones. According to Prof Tshifularo, head of the Department of Otorhinolaryngology at the University of Pretoria Steve Biko Academic Hospital, they only 3D printed the ossicles that were not functioning properly from titanium and replaced it endoscopicly. He believes that this breakthrough could provide a long-term solution in curing patients and even babies of hearing loss caused by damage, disease or infections to the inner ear. Hearing is restored immediately after the less than two hour operation.
The surgeons initiated the process by comprehensively scanning both the functioning and damaged ears of the patient before developing a personalised 3D model with the help of Computer Aided Drawing (CAD) software, whereafter some of the smallest bones in the human body was accurately printed on a 3D printer.
In China’s Shanghai Changzheng Hospital surgeons used a 3D printer to create titanium alloy bone implants for a cancer patient. The patient was suffering from a rare and particularly difficult-to-treat type of bone tumour that affected six separate bones in her spine. The six bones had to be removed to prevent the cancer from returning. The 13 hour operation was extremely challenging and risky, since it could leave the patient paralysed or dead if anything went wrong.
Over a period of three weeks, every element of the personalised bone implants were crafted with the highest degree of precision through the use of a 3D model of the affected vertebrae. The model was eventually printed using a sophisticated metal 3D printer, to ensure the implants’ dimensions were captured with perfect accuracy.
The implants were designed with a microporous structure so that they would integrate with the patient’s natural bone material. The operation was a huge success and the patient recovered fully.
As new materials are developed for medical 3D printing and the technology evolves to fulfil the sector’s stringent regulatory requirements, we expect success stories like this to become increasingly common, as more hospitals are inspired to explore 3D printing technology.
3D printing is also used in the step-by-step virtual planning of surgery and for 3D printed personalised instruments in many areas of surgery including total joint replacement and craniomaxillofacial (mouth, jaws, face and skull) reconstruction. One example of this is the bioresorbable (naturally dissolving) trachial splint developed at the University of Michigan to treat newborns with tracheobronchomalacia (flaccidity of the tracheal support cartilage leading to tracheal collapse).
In May 2018, 3D printing has been used for a kidney transplant to save a three-year-old boy. Surgeons at Guy’s and St Thomas Foundation Trust in London used 3D scanning and multi-material printing to verify that a father’s adult kidney would fit in his young son’s abdomen before the operation. It was the first hospital in the world to use 3D printed models to pre-plan the transplantation of an adult kidney into a small child. 3D printing can undoubtedly enhance the decision-making during pre-surgical planning, as well as in the operating theatre.
The 3D printing of a heart for the planning of complex operations or the education of medical students is nothing new. However, in April this year a team of Israeli researchers from Tel Aviv University revealed the world’s first 3D printed heart from biological material and the patient’s own cells. What makes this small heart unique is that it was complete with cells, blood vessels, atria and ventricles.
Cardio Vascular Disease still is the leading cause of death in South Africa after HIV/AIDS. Every hour in South Africa five people have heart attacks. Heart transplantation is often the only treatment available to patients with end-stage heart failure. But the waiting list for heart transplants is long and many patients die while waiting. The personalised Israeli 3D printed heart is made from human cells and patient-specific biological materials and may revolutionise organ replacement in the future.
Bioengineers at Rice University published in the Science of 3 May 2019 a new technique, which uses stereolithographical bioprinting to create entangled vascular networks that corresponds with the human body’s natural passageways for vital fluids such as blood and air. The researchers developed a hydrogel “lung” air-sac in which airways deliver oxygen to blood vessels. The team also managed to implant bioprinted constructs containing liver cells into mice with chronic liver injury.
This advance could make the printing of healthy, functional organs possible in future. Bioprinting is the process of layering living cells onto a gel medium or sugar matrix to create organic structures using 3D printing. Since 3D bioprinting uses bio-material from the patient it also reduces the risk of rejection of the transplanted organ. According to Prof Miller, a bioengineer from Rice University, the barrier to creating these organs is their complexity. To make these organs fully functional, they need a very complex network of vessels.
3D bioprinting and regenerative medicine (the restoring of damaged tissues and organs) should be watched closely since they could be the real game-changer for the medical world. It may seem like science fiction, but bioprinting may provide a fast and sustainable way of producing complex human tissues and organs for transplanting in a world where the waiting times for organs are long.
In the medical field, the enormous advantages of 3D printing are still being discovered. However, as knowledge of the capabilities of the technology increases, it is clear that 3D printing has the potential to transform the future of medicine. And as the field of medicine continues to evolve, the value of 3D printing technology will only continue to expand.
Professor Louis Fourie is the deputy vice-chancellor: knowledge & information technology at Cape Peninsula University of Technology.