Additive manufacturing (AM) is already a disruptive force in healthcare. 3D printing already delivers FDA-approved spinal and hip implants, along with digital models and advanced medical instruments.
In the future, AM processes may also deliver living prosthetics, blood vessels and organ tissue. The pursuit of this exciting new reality is already underway, inspiring everyone from biomedical engineers to medical professionals.
A report by IndustryARC projects a compound annual growth rate (CAGR) of 18 percent for additive manufacturing in healthcare through 2020. One of the driving forces of such growth is the growing demand for patient-specific orthopedic and maxillofacial implants.
How 3D printing is changing healthcare
From the creation of 3D models that help surgeons plan operations to the fabrication of titanium implants, 3D printing is already changing healthcare.
Digital models aid pre-surgical planning and enhance patient satisfaction. When a New York woman with an unusual type of brain aneurysm required life-saving surgery, surgeons could not opt for traditional surgical solutions due to difficult twisting of the blood vessels. Digital information acquired from scans of the patient’s brain was used to print a thermoplastic prototype of the twisted mass of blood vessels. The polymer used to print the digital model of the blood vessels mimics human tissue, enhancing pre-surgical planning. The woman afflicted with the problematic aneurysm underwent successful surgery.
In a study of 30 patients with fractured ankles, researchers reported shortened operation times and decreased intraoperative blood loss. Authors of the study asserted that “patients and family members exhibited a high degree of satisfaction regarding the use of a 3D-printed fracture prototype by the doctors to explain the details of fracture and for preoperative communication.” Researchers found that the use of pre-operative models increased accuracy, lowered risk and reduced operation times.
3D-printed medical devices
Single-use medical devices address the reality that every person is unique. In a variety of ways, additive manufacturing (AM) is an answer to healthcare’s quest for truly individualized treatment.
The cost-effective production of many medical devices presents a real challenge, because traditional manufacturing methods work well with the economies of scale, but not when there are one-off or short-run requirements. As a result, the cost of many customized or low-volume devices often rises. AM processes meet the need for high-quality medical products fabricated in small quantities, often at a lower price.
Orthopedic implants and other medical devices printed by electron beam melting (EBM) machines like the ARCAM Q10 Plus have already garnered FDA approvals. The FDA identifies 3D-printed orthopedic implants, cranial implants and surgical instruments as medical devices, which are regulated by the FDA’s Center for Devices and Radiological Health (CDRH).
Superalloy metal powders like Titanium Ti6Al4V and Arcam ASTM F75 Cobalt-chrome are melted at high temperatures by an electron gun operating in a vacuum chamber. Such systems are particularly well-suited to the production of one-of-kind implants.
Quick, clean, reproducible suturing during heart procedures improves patient outcomes while addressing the problem of needlestick injuries that impact an estimated 240,000 medical personnel every year. Suturing devices developed by Sutrue automate stitching during heart operations. An Mlab cusing machine from Concept Laser uses direct metal laser melting (DMLM) technology to fabricate parts for these suturing instruments.
Additive manufacturing is also valuable to the medical profession because it can be used to fabricate sterile, disposable instruments with complex geometries that are adapted for individual patients. The quick delivery of high-quality instruments with exacting dimensions advances patient care. On-demand fabrication of medical devices promotes cost-effective inventory reductions as well.
It is also possible to combine 3D printing and semiconductor technology to create a new generation of micro-instruments that are less invasive and more precise. The parts for such instruments could not be assembled using traditional methods. However, 3D printing allows for highly complex, single-part constructs that reduce or eliminate common assembly obstacles.
For example, one collaborative effort focuses on the development of a tiny biopsy forceps that could improve the reliability of biopsies of pancreatic cystic lesions. Improved differentiation between benign and malignant growths is an essential step in the quest to diagnose and treat pancreatic cancer.
3D-printed orthopedic implants
One might say that the speedy delivery of tailor-made, 3D-printed implants is, quite literally, “just what the doctor ordered.” The precise design of biocompatible body parts may reduce complications during the implantation process and improve overall health in the post-recovery period. Prior to the advent of 3D-printed implants, the manufacturing process was often more cumbersome and labor-intensive. Additive manufacturing direct from digital information introduces speed and accuracy into a highly efficient process.
AM offers yet another advantage. Electron beam melting using a titanium alloy allows for the fabrication of orthopedic implants with just the right amount of surface roughness for prompt and proper bone fusion. Roughened-surface titanium screws produced by EBM demonstrate enhanced osseointegration compared to traditional smooth screws.
AM’s progression from polymers to metals and now to ceramics opens up additional possibilities in the medical field. At Washington State University, researchers want to create highly detailed calcium phosphate (CaP) ceramic structures that serve as scaffolds upon which bone can grow.
When this material is used as a coating on titanium-alloy hip and knee implants, it is hoped the implants will last much longer than the typical 10-12 years. Researchers believe that coatings based on 3D-printed ceramic structures may double the lifespan of such implants. Since there are more than 200,000 load-bearing hip implants cemented into place every year, the stakes are high.
Looking to the future: 3D-printed organs
Bioprinting using living cells is a new development in 3D printing. The first patent pertaining to bioprinting was granted in 2006. Although 3D-printed synthetic organs are not yet a viable option, they may be in the future.
In 2014, researchers created the first bioprinted liver tissue. It has been successfully implanted into mice, with preclinical data revealing successful tissue engraftment and vascularization. Ultimately, 3D-printed liver tissue might be used to treat inherited metabolic defects such as those associated with cystic fibrosis. 3D printing has also come to kidney research. In 2017, a partnership between the Murdoch Children's Research Institute in Melbourne, Australia, and Organovo yielded the first bioprinted kidney tissue.
There are also advances in the 3D printing of organ models that will help physicians better plan for surgical procedures. They may also aid pharmaceutical research into drug toxicity, bypassing the traditional use of animal models in the process.
3D-printed synthetic organs show promise as well. In Switzerland, researchers have demonstrated proof of concept in testing an artificial heart produced via 3D printing. In the future, it is hoped that some of those on lengthy organ donor lists will undergo lifesaving implantation of 3D-printed organs.
3D printing biomaterials
Bioprinting employs “bio-inks” to create organ tissue, scaffolds for joint regeneration and other medically valuable materials.
There are different forms of bioprinting. For example, one technique uses a build material consisting of living cell structures combined with liquids that deliver essential oxygen and nutrients. The process is somewhat similar to traditional 2D inkjet printing, although sequential layering builds up a three-dimensional object.
Another technique fabricates structural scaffolding useful in promoting tissue and joint regeneration. The capacity of 3D printing to create micron-level detail allows for scaffolding with the required “pore interconnectivity, pore size, porosity, and mechanical properties.”
Tissue engineering that produces functioning blood vessels, bones and heart valves is yet another medical breakthrough attributed to 3D printing.
Harvard researchers want to combine living cells and 3D-printed structures to produce vascular networks capable of evenly delivering vital nutrients and fluids to human tissue. It is hoped that using bioprinting to create blood vessels will eventually be used to accelerate the healing of damaged tissue.
Researchers at the University of California - San Diego are also developing 3D-printed blood vessels that integrate with the circulatory system. A key to the research is achieving success in 3D printing structures capable of branching out like regular human blood vessels. Advances in such research may assist in solving the challenge of circulating blood in bio-printed organs.
Researchers at Cornell University are using bioprinting to combine living cells and structural scaffolding to produce living prosthetics, including heart valves.
Although non-living, prosthetic heart valves already save lives, their use is often restricted among infants and children. In cases involving younger patients, the need is significant. According to the Children’s Heart Foundation, about 1 in 100 newborns has a congenital heart defect, the most common birth defect of all.