Rebuilding the face: medicine meets engineering at the beginning of an industrial revolution
By Loz Blain
February 10, 2009
Mass-production technology has revolutionized so much of modern life that we take it for granted - but early iterations of all technologies were hand-built, relying on the skills and intuition of master craftsmen for the effectiveness of each end product. It might surprise you to learn that in the field of facial reconstructive surgery, the vast majority of work is still being done in a pre-industrial revolution fashion - and results for patients who present with horribly disfiguring facial tumors or bone injuries are as varied and inconsistent as the human hands that do the work. Dr. Ninian Peckitt, originally from the UK, has pioneered a truly revolutionary "Engineering Assisted Surgery" approach that uses advanced CT-to-CAD modeling, rapid stereolithographic prototyping, pinpoint CAD design, electron beam melting (EBM) mass-production and error-eliminating surgical procedures. The results are absolutely stunning. Patients that would normally require traumatic 20-hour operations involving complicated, imprecise and ugly bone grafts are being fitted with incredibly precise, long-lasting titanium facial inserts so effective that once surgical scars fade you'd never know they had a facial injury. Surgery is simple and can often be completed in an hour or two using techniques that eliminate human errors - and the entire procedure comes in at a fraction of the price. Peckitt's work is amazing - but if powerful lobbies in the medical fraternity have their way, it may cost him his career.
Facial injuries have severe and traumatic repercussions that can make life incredibly difficult for patients - just ask New Zealander Sophie Bell. Sophie suffered a benign tumor that started in her cheek and spread to her nose and sinuses, eventually causing breathing difficulties.
The tumor was removed, and with it her palate, cheekbone, parts of her temple and eye socket. The left side of Sophie's face was rebuilt using the standard "free flap" procedures. In a long and complicated series of operations, bone was taken from her leg, sculpted into shape and implanted into her face, then connected to the blood supply in order to keep it alive and healthy.
Thanks to the skill of the surgical team, Sophie's reconstructed face looked "magnificent" when the surgery was first completed - but the subsequent swelling, gravity and other pressures on the implanted bone have caused the left side of her face to sag, dropping her eye out of alignment, giving her double vision, and resulting in a noticeable facial deformity that scared her own kids when they first saw her, and has battered her self confidence in every area of her life.
In the next couple of months, Sophie Bell will receive a titanium implant to replace the grafted bone in her face. Surgery will be incredibly fast – estimated at around three hours - and she may well go home after only a day or two in hospital with a minimal surgical procedure and minor scarring. The implant will fit perfectly against the bone, so tight at the joins that you won't be able to get a dental probe underneath it. It will be coated with a Bone Morphogenetic Protein (BMP) that causes bone to form over the surface of it, helping the skin above the implant to receive a steady blood supply. Sophie's eye will once again be supported exactly where it should be. Her vision should return to normal in time, and her pretty face will once again be whole. She will be fitted with customized dental crowns to restore her teeth. The transformation will be incredible, the impact on Sophie's life incalculable.
Dr. Ninian Peckitt, Sophie's surgeon, can say this with justified confidence, because the operation has all been planned out using the same principles that have revolutionized so many other industries across the globe: systemization, Computer Aided Design (CAD), rapid prototyping and precision engineering. He can also say that the results will last for decades, that the surgery will be many times cheaper than Sophie's original free flap procedure - and that the inserts themselves will rapidly reduce in price as production volume increases.
Peckitt, a maxillofacial surgeon originally from the UK, has been working in New Zealand's public health system for the last 2 years. Since 1993, he has been developing, trialling and refining a set of techniques he calls "Engineering Assisted Surgery" that seek a scientific, replicable and efficient alternative to free flap operations - but the true potential of the system he has pioneered goes far beyond facial reconstructions.
Peckitt's system for dealing with a case like Sophie Bell goes along the following lines:
Firstly, a high resolution CT scan is taken of the patient's skull, giving layer-by-layer dimensional data about the bone structure, the injury, any tumors and other issues.
Then, this CT data is processed into a hugely complex set of CAD data, so that every fine detail of the skull and its current imperfections can be replicated in 3D on a design computer.
Using this CAD data, a laser is passed over a bath of resin layer by layer to build up a physical model of the skull. A special resin can be used if required that solidifies and goes translucent when the laser passes over it once, but turns red if the laser passes over it a second time - allowing tumors or irregularities to be visually highlighted. It takes around 20-24 hours for the modeled skull to rise up out of the resin bath.
A cheaper alternative to this stereolithography process, used in less complicated cases like Sophie's, is Fused Deposition Modeling, which extrudes small beads of thermoplastic material to form layers as the material hardens immediately after extrusion from the nozzle. It is slightly less accurate than stereolithography but tolerances are well within those required for surgery.
With the physical model, the CAD design and photographs of the patient's face from several angles, Dr. Peckitt can decide exactly where existing bone needs to be removed and in order to produce a symmetrical and structurally sound face.
At this point, he is able to take CAD data from the unaffected side of the patient's face, copy it and flip it over to the other side. Because facial structure is rarely perfectly symmetrical, Peckitt stretches and adapts the copied structure slightly to fit the contours of the affected side, and builds in the points where it will be attached to exposed bone where damaged or diseased bone has been removed.
Once the insert is designed, it can be produced in plastic for testing - after which it will be manufactured in titanium using another layer-by-layer process called Electron Beam Melting (EBM). EBM allows complex shapes to be constructed that normal 5-axis milling would be unable to recreate. It virtually eliminates material wastage, produces strong and high-density parts and allows a design resolution down to the width of a red blood cell. Best of all, despite the fact that each insert is an intricate custom design, EBM has low costs, comparable to casting.
Peckitt then uses the resin skull model to design a surgical jig that attaches only to specified points. The jig is designed to eliminate human error on the operating table by giving the surgeon clear lines to cut against when removing bone, and providing only one path of insertion for the implant, and a perfect fit.
Importantly, the entire procedure up to this point has been performed outside the theater. By the time Peckitt is ready to operate, the procedure has been meticulously mapped out, prototyped and rehearsed.
Once the patient's face has been opened up and the jig attached, the remainder of the surgery is amazingly quick. Within in hour or two, a surgeon can excise the necessary bits of bone, fit the implant, screw it into healthy bone and sew the patient's face back up. Minimal operating time equals vastly reduced trauma to the patient, swelling and complications. Many of Peckitt's patients have had significant parts of their faces rebuilt in this manner and have walked out as day patients with a new appearance and a new lease on life.
So far, the Engineering Assisted Surgery process has yielded outstanding results - one of Peckitt's first 'guinea pig' patients, an elderly British lady, has lived for the last 12.5 years with a full titanium palate and upper jaw. She's delighted with it; her only complaint to date has been that the rubber rings that help hold her denture in place against her titanium palate have worn out, and she needs a replacement - at a cost of about 20 cents - to keep her denture snugly fitted. Peckitt has had many such successes, a list of vastly improved lives to which Sophie Bell is delighted she'll soon be added.
The EAS method can easily be applied outside Dr. Peckitt's Maxillofacial specialty as well - the techniques could be used to create artificial hips, for example, custom tailored to the patient and impossible to dislocate. Rather than banging a standard artificial hip into the femur on a long spike with heat-setting cement, the custom titanium implants could be fused to the bone for a stronger, longer-lasting and less traumatic solution.
So here we have a medical technology that is vastly superior from a patient's point of view because it is quicker, less invasive and creates a near-perfect result in a single operation. It outlasts the current solutions (the first titanium dental implants lasted forty years - and would have lasted longer if the patient hadn't died of old age). It replaces a long, complex and 'creative' operation with a lightning-fast procedure, and the system eliminates human errors.
On top of that, the production process is accurate, efficient and relatively cheap, which means that public health boards and health insurance companies stand to cut their costs on a single facial reconstruction by up to 50%. Peckitt welcomes any scientific enquiry into the techniques and has amassed a reasonable volume of clinical data over more than a decade to prove its efficacy.
The financial and career implications of the technology have won Peckitt some significant enemies in New Zealand's medical establishment, particularly among plastic surgeons whose Clinical Centres stand to lose referrals and will suffer financially from a system that tries to remove the master craftsman from the equation and replace his creativity with proven, replicable and perfectable systems.
But Peckitt believes that in the best interests of patients, insurers and public health boards, it's time the industrial revolution came to medicine. He will move to Sydney, Australia later in 2009, where he will begin in private practice to deliver the service straight to the public. He is an Hon. Research Fellow at Massey University's Centre of Engineering Assisted Surgery in New Zealand, has presented papers to an enthusiastic reception at the Australasian Academy of Facial Plastic Surgeons in Sydney, and feels that once the technology's financial benefits are demonstrated in a series of private practice franchise-type operations across Australia, the public sector will have little choice but to follow.
Peckitt will be running a series of international workshops on Engineering Assisted Surgery throughout 2009, ending the year with an International Workshop in Wellington 7-8th December 2009 - "Mechatronics in Medicine and Health" chaired by Gurvinder Virk, Professor of Robotics at Massey University. It's not hard to see how the EAS and Robotics fields might integrate in the future, with robot surgeons able to diagnose, scan, build and fit implant solutions.
Peckitt is seeking a partnership with a business manager capable of taking the enterprise global while he concentrates on his first passion - refining the technology to deliver the best possible patient outcomes. He is an inspirational character, a visionary, a fighter and a humanitarian. We wish him every success in his Australian endeavors.
As for Sophie Bell, she'll get her old face back at the end of this month. Dr. Peckitt has scheduled her operation around a Billy Connolly performance in Lake Taupo - he jokes that she should probably go watch the "Big Yin" before the surgery so he can fix any additional laughter-related damage while he's got her there on the table. The operation and her recovery will be filmed by New Zealand's Attitude TV with plans for presentation through Discovery Channel.
Below is a video of a presentation that Dr. Peckitt gave to an enthralled audience at the Melbourne TEDx event at Monash University, Caulfield. Be warned, the presentation contains some graphic surgical images.
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