3D Printing And The Future Of Lower Extremity Care

As the technology of three-dimensional printing becomes more ubiquitous, these authors note that 3D printing could be a viable adjunct for surgical planning and orthotic fabrication, and suggest that increased access to this technology may have broader implications on healthcare delivery in the future.

Three-dimensional printing has become an awe-inspiring, household term for the creation (and recreation) of amazing items, and we suspect it will play a major role in the forthcoming third Industrial Revolution. As we will have the ability to rapidly create and iterate physical objects much in the way that we have been able to create and modify computer files, the only thing that remains clear about the future of this disruptive technology is that it will drive change.

In practical terms, 3D printing is nothing more than a newer means of manufacturing. Original patents for 3D printing date back to the late 1970s and early 1980s as it was originally referred to as “rapid prototyping” or stereolithography. As with desktop paper printers of that era, 3D printing was crude and low resolution in comparison to today’s standards. However, 3D printing (or additive manufacturing as it is more properly known) largely went unnoticed until this current decade. Why is that? Supply and demand.

Rapid prototyping machines originally required a bit of technical expertise to operate and were prohibitively expensive. Prices of these machines ranged from three to ten times more expensive than the cost of a reasonable desktop paper printer. It was not until these original technology patents expired in the late 2000s that tinkerers and hardware hackers began developing inexpensive desktop-sized 3D printers. Although the reliability and overall quality of these printers were fairly poor, the use of these printers was a truly captivating experience for many technology enthusiasts of their time, and the open-sourced designs became a foundation for much of what the mainstream media has popularized.

Today, some of the more common demonstrations of 3D printing in education, art and commercial business are part of an overnight explosion that is a quarter of a century in the making. In what direction does this lead the next five to ten years of everyday manufactured goods and services?

To understand additive manufacturing, it is important to understand manufacturing in general. As you read this article, the large majority of everything surrounding you was likely manufactured by one of several processes. Casting, molding, forming and machining are the most common categorical descriptions. Everyday examples include a craft doorknob poured from a cast, injection-molded protective smartphone cases, vacuum-formed plastic bottles and machine-carved (a.k.a. subtractive manufacturing) wooden table legs. Additive manufacturing is essentially just one more member of this family.

Additive manufacturing is a process that starts with nothing and creates the final product one layer at time. Three-dimensional printing is showing great promise with exceedingly intricate manufacturing capabilities as well as custom applications. Whereas most of the previously mentioned processes have inherent limitations to complexity with corresponding cost increases, 3D printed products often do not increase in price or time when one adds more details to the printed result.

Can 3D Printing Reinvent Surgical Planning For Complex Deformities?
Three-dimensional printing has become a poster boy for Silicon Valley technological innovation and status quo disruption. As empowering as this may seem, 3D printing still has a longer and gradual transition, and has yet to achieve widespread, everyday use. However, this movement is already inspiring healthcare modalities, generating new opportunities for personalized patient care and pre-surgical education via the utilization of computer drafting and additive manufacturing (3D printing).

Complex, challenging surgical procedures have the potential to create stress on care providers and patients alike.¹ Research has shown that these stressors have the potential to adversely affect intraoperative performance and human interactions, ultimately reducing the quality of patient outcomes.² Multiple researchers have investigated methods of reducing stress and improving operating circumstances in a variety of theaters.^3-5

The reconstruction of complex deformities secondary to Charcot neuroarthropathy continues to pose challenges for diabetic limb preservation efforts. Failure to properly address this problem has the potential to reduce mobility and increase mortality.⁶ The senior authors have previously described the use of simulated perioperative surgical planning by means of computer-aided design (CAD) software as well as computer-aided manufacturing (CAM) methods via additive manufacturing.⁶ In this article, the senior authors described a novel, inexpensive 3D template printing technique that uses a normal printer to produce multiple “copies” of the foot that is slated for surgical repair. We believe one could use this technology to plan surgical repair or revision of other complex foot deformities.

Surgeons have likewise replicated this technique in orthopedic and other surgical specialties. Zein and colleagues described the use of 3D printing to simulate liver transplantation.⁷ These advantages of simulated surgical planning are further elucidated in the field of neurosurgery, where researchers have observed complex challenges and considerations.⁸ Modeling advantages to additive manufacturing and computer-assisted design are also happening in pediatric plastic surgery.⁹

While simulated perioperative surgical planning functions well as a surgical training tool and a tangible adjunct for patient education, it is likely still too costly and cumbersome for high volume workflow.

Much of these accomplishments are admittedly miniscule in comparison to the glaring potential benefits that additive manufacturing could bring to individualized regenerative medicine. Atala and his tremendous work with bioprinting of tissues and organs demonstrate some of these advantages.^10,11 While stem cells alone have limitations with growth patterns and morphogenetic tendencies, additive manufacturing may overcome many challenges to organ replacement and other pathologies such as tissue degeneration in people with arthritis.

Does 3D Printing Facilitate Increased Access, Collaboration And Innovation?
Recently, popular crowdfunding opportunities have laid the foundation for progressive market developments, increasing widespread “homebrew” endorsement for personal additive manufacturing platforms. In tandem, works to make products more available and low-cost by the “open source movement” have pioneered renovations in recently expired software, successfully “remixing” purchaser-only applications into industry-leading “free to use” programs.

Previously, the exploration and advancement of technology was the sole work of industry professionals or highly skilled enthusiasts. A relatively new phenomenon termed “hackerspaces” or “makerspaces” has brought about nationwide venues for hobbyist, educational and collaborative work, facilitating a dynamic change in the availability of resources.¹²  These movements strive to lower the barriers to education and training, revolutionizing the means by which we obtain individual skills. Direct examples of this include Makerspaces in Tucson and Atlanta. In addition, the triad of increasing machine capabilities, decreased material and technological costs as well as patent expiration in tandem with the aforementioned educational centers have led many theorists to predict an upcoming third Industrial Revolution.^13,14

The resonating effects of these penetrating sociological ideals and educational opportunities are quite intriguing. It is likely that many of these principles will produce unexpected results, circumventing the accepted limitations of education and defying established socioeconomic rules and traditional business models.¹⁵ Disruptive changes as a result of technological advancements are a common thread throughout human history.

Just as the widespread adoption of viable free software and rapid Internet connectivity disrupted the previously accepted form factor of purchasing compact discs, it is our belief that the current healthcare practices will be revolutionized by the concepts currently developing by the means of homebrew, think tank and startup technology operations. While the safety and legality of these practices have yet to resolve, the end result is no less inspirational. Never before has a consumer been so connected with a digital engineer, an evolving relationship already influencing widespread commercial segments. The advances in all 3D technologies, from 3D design, scanning and capturing, “augmented reality” and additive manufacturing, can theoretically help “open source” the world itself. In the coming decades, digital sharing and replication of everyday commodities may be as accessible as current consumer technology.

Additive manufacturing will likely not replace everyday items until the material properties of these goods can improve. Currently, additive manufactured materials do not hold up well against repetitive loading and high impact forces like many traditionally manufactured goods do. Also, there is a significant limitation on material choices. Improvements to resolution, printing methods and chemical mediums will likely overcome much of this in the next 20 to 30 years.

Will 3D Printing Redefine The Roles Of Healthcare Providers?
Orthoses and prostheses, perhaps like no other technologies in podiatric medicine and surgery, may conceptually benefit from the democratization of 3D printing. Already, many “legacy” orthotic companies advertise the use of variants of additive manufacturing in this area. The fact is, however, that this technology has been around in one form or another for a long while. Whether the near term shows benefits from 3D printed insoles over other insoles remains to be seen. The particular excitement in the area involves “homebrewed” technologies that may result in a greater number of individual clinicians (and perhaps individual patients at some point) making their own orthoses.

While this sounds heretical, we believe that it is ultimately inevitable. Whether this fundamentally changes the roles of podiatric and orthopedic surgeons, physical medicine and rehabilitation specialists or prosthetists from “prescriber” to “adviser” remains to be seen. Additionally, issues surrounding intellectual property for these technologies are no less complex than when the Napster file sharing service upended the music industry in the 1990s.

Where Do We Go From Here?
The social implications of 3D printing’s advancement will likely be very profound and yet unexpected. Although bootlegging and digital piracy are major concerns for product designers and patent holders, premium services will still likely rise to prominence among the noise. One meaningful comparison is with streaming media, whereby “free-to-play” models exist with support from advertising revenue.^16,17 Donations and the recently described “thank you economy” are showing increased gains.¹⁸ Naming one’s price and patron support of content providers are becoming prominent business models.

YouTube may be the best example of this from the authors’ perspective. From a variety of hardware machines running several different operating systems and web browsers, users are able to experience a variety of different content. Users can upload artist- and user-generated content, and advertising revenue supports the means of hosting. Users can upload, download, share, promote, comment and vote on content based on merits or relevance. This fundamental platform has been one of the centerpiece platforms of social media, next to Facebook and Twitter.

Whereas the Internet provides the digital backbone of this tight social integration, digital 3D models and blueprints will also be shared and created by collaborative social efforts. This future is both promising and somewhat startling based on recent news. Less than three months apart, popular news outlets promoted coverage of both a 3D printed handgun, “The Liberator” and a 3D printed prosthetic hand replacement for children, the “Robohand.”^15,19-20 Additive manufacturing is yet another empowering technology for the masses.

Could medical care providers and patients soon be witnessing a rapidly evolving change of interaction and delivery of service? Scientific literature as well as popular news sources have already demonstrated significant enhancements to medical treatments as a direct result of novel collaborative efforts and technology. Many of these stories emphasize the partnership between physicians, surgeons and scientists as being critical to positive outcomes. For instance, our team has worked with teams of surgeons at UCSD to rapidly prototype a human ear to surgical repair a congenital defect (microtia) by simply scanning the healthy ear and “flipping” it 180 degrees much as we would do in Photoshop before sending the template to a 3D printer.⁶

Additionally, the continued collaboration between patients and physicians further demonstrates an independence from commercial reliance. As the influence of consumer-driven technology subverts the industry-dominated creation and delivery of media, so too will the influence of patient-centered technology supersede the industry-dominated formulas for healthcare diagnostics and treatment. The ability to self-generate will continue to emphasize inexpensive personalized care, pushing traditional industry further from the frame of influence in the healthcare setting. Healthcare stands to benefit greatly from these technologies, both from large industrial and academic developments in machine design and sophistication, as well as from the consumer and hobbyist level.

Mr. Miller is a third-year podiatry student at Des Moines University and a former research intern with the Southern Arizona Limb Salvage Alliance (SALSA).
Dr. Giovinco is an Assistant Professor in the Department of Surgery at the University of Arizona. He is the Director of Education with SALSA.
Dr. Armstrong is a Professor of Surgery at the University of Arizona College of Medicine. He is the Director of SALSA.

References

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