ADDITIVE MANUFACTURING feature
AT THE SPEED OF LIGHT —
ADDITIVE MANUFACTURING OF CUSTOM
MEDICAL IMPLANTS
Stephen Rouse
Stephen Rouse, Doctor of Dental Surgery and Director of 3D Medical
Applications Center, part of the Department of Radiology at the Walter
Reed Medical Centre, Washington, D.C., US
T
ime has always been one of the greatest enemies of Mankind. As soon as
we are born, we start to die. There is a lot of truth in the old statement, and
most of the history of medicine is wrapped up in the attempt to prolong our
lives. Ancient and current history is full of examples of timely or rapid
intervention in the course of a disease or injury that saved or prolonged many
lives. From the discovery of bacteria and other micro-organisms that cause
disease, to X-rays and other technologies that help us to diagnose and treat
disease, the recent history of medicine is laced with advances in technology.
Since the advent of implantable devices, we have faced the necessity of
modifying the patient to fit the needed implant selected from a catalogue of
available products. For many, this is a reasonable, and indeed, the only decision
that can be made.
The development of equipment for Additive Manufacturing (AM) — aka: Rapid
Prototyping — has been a big boon to those in the medical community who
utilise it, resulting in better prepared surgical teams, reduced operating time with
its concomitant reduction in blood loss and anesthesia, better outcomes, and
reduced morbidity or risk of additional complications. With the advent of the
newest AM technologies, especially those that allow direct manufacture of
implantable metal components or devices, we are able to create patient specific
implants, fixation devices, and other devices or instruments, including those
needed for post trauma care.
MAIN IMAGE: Electron beam melt pool
Dental copings for porcelain fused to metal crowns or bridges in bio-compatible prior to surgical fixation. This delay ranges from 7–14 days post-injury. Our aim
cobalt chrome alloys have been successfully manufactured and used for several was to receive the relevant data from the surgeon, including Computed
years using this AM technology. (Methner, 2007) Unlike most areas of medicine, Tomography (CT) scans and the needed prescription, and have a custom implant
dental fillings, crowns, fixed bridges and removable partial dentures are all patient or fixation device designed, built, sterilised and delivered within the 7–14 day
specific. Most dental implants are an off-the-shelf purchase from established window. This allows the surgeon to plan the surgery between the reduction of
manufacturers, but there is still a need for sub-periosteal custom implants, as swelling and the onset of healing.
well as other intra-oral implants designed to replace bony structures missing due
to trauma or disease. These must be custom manufactured and in most cases are The heaviest requirement for stereolithographic biomodelling is for massive
not suitable for casting or milling applications. orthopaedic trauma. Next in line are those patients with severe craniofacial
injuries, followed by traumatic brain injuries with craniectomies. In most of the
The choice of the exact technology to use for patient specific custom devices orthopaedic and craniofacial injuries, our responsibility ends with pre- and post-
should be directly related to the application or product. For our purposes, we surgical models. Standard, off-the-shelf fixation plates are used in the surgical
wanted the ability to manufacture and deliver within a timeframe that was specific repair of these wounds. Unlike the orthopaedic and facial fractures, there are very
and limited, which means that build speed and consistency were critical. Severe few options for off-the-shelf implants for craniectomy repair, or cranioplasty. For
orthopaedic trauma is normally stabilised and the swelling allowed to diminish small openings, the standard sheet of titanium mesh works quite well, as does
tct 17/6 47
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64