Over the last five years, there has been significant growth in the adaption of 3D printing in hospitals. This is a result of a more clarifying regulatory landscape, more governmental supports, and new public and private initiatives. Notable relevant public initiatives are led by RSNA SIG group, Mayo Clinic, ASME/SME, FDA, America Makes, ARMI. Notable private initiatives are led by JNJ/Depuy Synthes, GE, HP, Stryker, Medtronics, Lima Corporate, Materialise, Formlabs. The concerted efforts from the private and public sectors resulted in a rapid increase in hospital-based 3D printing labs all over the world. This is further supported by consistently increasing publications on Pubmed. [Figure 1, Source: Pubmed] Within a hospital setting, current major applications remain to be pre-surgical planning, which will comprise the bulk of our discussion.
However, lately, there are two defining directions in the field: point-of-care 3D printing and mass-produced 3D printed implants in the 3D printing healthcare sector, which makes 3D printed personalized implants a possibility for hospital-based 3D printing services. We will incorporate these into our discussion.
Why this Guide?
Despite the progress, the field remains new, and the most popular questions remain to include the following:
- How do we set up a 3D printing center in a hospital?
- How can this make economic sense for a hospital?
- Should we have a 3D printing center in the hospital (in-house) or should we outsource such service?
These are exactly the same questions five years ago when I co-authored a book focusing on a systematic thinking process to address these questions by evaluating components of operational management with Michelle Gabriel. However, selling a book is not going to accelerate adaption, instead, I decided to publish this updated online version of 3DHEALS Guide in five digestible parts, focusing and adding new information from field experts from all over the world to provide a foundation to any early adapters.
This is not a show and tells of various fancy technologies and artful displays, but a fundamental thinking exercise to help people through their initial steps of setting up 3D printing service in hospitals. I hope to use simple languages understood by business, engineering, and healthcare professionals collectively to bridge the gaps in communication. If you find this guide useful, feel free to share it to your fellow makers/innovators. This guide will stay indefinitely free.
This guide is an ongoing project for 3DHEALS and will be updated regularly. We are also working on a page dedicated to all the contributing individuals and organizations for current and future updates, please stay tuned.
The target audience of this guide is wide, including providers, hospital administrators, organizational leaders, entrepreneurs, legal experts, additive manufacturing industrial partners, and investors, among others. Given our broad networks, we hope to maintain the latest wisdom with the help of 3DHEALS partners and community managers.
What’s in this Guide?
This guide will first give a technical overview of 3D printing. Then, we will focus on major operational management issues for hospital implementation of this technology including sample cost analysis and interactive online tools. The book will include clinical examples illustrating the process from idea to implementation, referencing major published data/papers as well as our interviews with early adopters and industrial leaders.
Speficially, the guide is broken down into the following components:
- Introduction: What is operational management?
- Technical Background
- Strategic Issues
- Tactical Issues
- Financial Issues (To be published)
- Financial Worksheet (To be published)
- Acknowledgments (To be published)
Introduction: What is Operational Management?
So what is Operational Management?
Here is a simplified explanation for those who are unfamiliar:
Operations management is the administration of business practices to create the highest level of efficiency possible within an organization. It is concerned with converting materials and labor into goods and services as efficiently as possible to maximize the profit of an organization [Ref]. In this guide, the goal is to maximize such efficiency in the context of 3D printing in hospitals.
In this guide, the issues related to operational management are categorized into three (Table I) [Ref]:
Strategic issues answer the questions “what” and “why”.
Strategic thinking, planning, and actions are rooted in the following company’s abilities:
- Ability to understand the environment they operate within.
- Ability to recognize developing industrial patterns and trends.
- Ability to anticipate potential issues.
- Ability to predict outcomes and impact of planned initiatives.
- Ability to develop sound fallback plans to mitigate the risk of a miscalculation.
Strategic planning in particular deals with the mission and purpose of the organization, its value proposition, i.e., what value it delivers to the customer, as well as the company’s future direction and growth.
That is, are we focusing on the right thing?
Tactical issues answer the question “how”.
Tactical consideration refers to how the company plans to get the job done or achieve a particular strategic objective. Tactical planning considers the resources available (time, money, people) along with the risks or challenges that may be encountered. Based on tactical consideration, the company determines the most efficient way to use resources to achieve strategic goals with quality results.
That is, are we doing things right?
Financial issues answer the question of “how much”. In healthcare areana, it includes a discussion of “reimbursements“.
Doing business in healthcare is not a straightforward “profit-and-loss” spreadsheet. The reimbursement pathway of emerging technology is tortuous, and the pricing strategy of devices and services is even more opaque to most.
2. Technical Background:
- 3D Printing Techniques and Materials
- Typical 3D printing workflow
- Values and limitations of 3D printing
- 3D Printing for pre-surgical planning
- 3D Printing for Implants
A. 3D Printing Techniques and Materials
3D printing techniques have grown since the first stereolithography (SLA) systems were created in 1986. The nomenclature surrounding the printing techniques has suffered from a lack of standardization. Recently, the American Society for Testing Materials (ASTM) designated seven 3D printing processes, each of which is represented by one or more commercial technologies. [Ref] The following table lists the processes, the technologies, the printing resolution of these technologies, and the medical applications that can be produced by each process (Table II).
Each process uses specific materials with specific properties that relate to medical applications, which are summarized in Table III.
With this general information as a starting point, users should be able to determine what methods and materials could be used for their specific needs.
Currently, 3D printers are either high-end or high-performance machines for industrial applications or very low-end and low-capability machines for hobbyists. New mid-priced, good-quality printers have started to emerge. Predictions are that these will be used by small- to mid-sized businesses that will grow the market in 2016. [Ref]
The emergence of these new printers has been driven by the expiration of key early patents for the different technologies, including SLA in 2009 and Fused Deposition Modeling (FDM) in 2011. [Ref] The most recent is Selective Laser Sintering (SLS), whose patents expired in 2014. [Ref]
B. Typical 3D Printing Workflow
A typical 3D printing workflow includes the following steps:
- Image acquisition
- File manipulation (i.e. segmentation, DICOM to STL file conversion, File optimization for 3D Printing)
- 3D Print
- Post-processing and polishing
- Validation and quality control
There are quite a few publications with more comprehensive and detailed discussions on the technical aspects of how to optimize each step. [Ref, Ref, Ref] This section serves as a summary of the process and to familiarize the audience with typical healthcare 3D printing terminologies:
a. Image acquisition
Many surgical patients today will have a cross-sectional imaging exam prior to surgery. Cross-sectional imaging exams in general include Computed Tomography (CT), Magnetic Resonance Imaging (MRI), ultrasound (US), and Digital Rotational Angiography (DRA). However, if the surgical team anticipates using 3D printing for surgical planning, suitable imaging protocol becomes the first critical step. [Ref, Ref] For adult patients, the optimal axial slice thickness depends largely on the anatomic structure of interest, and should be around 1 mm to 2 mm. For pediatric patients, the slice thickness could be thinner, in the sub-millimetre range.
Similar to 3D surface rendering, while it is still possible to construct a 3D object using slice thickness greater than 2 mm, a lot of anatomical information will be missing, and the clinicians need to be aware of the degree of inaccuracy in the final print. If vascular structures are of concern, intravenous contrast is needed with adequate bolus timing like any other vascular imaging study.
In general, the goal of imaging acquisition is to obtain images with enough structural contrast for later segmentation. Other important factors to consider include kernel selection, CT dosage, and MRI sequence. If 3D printing is considered as part of surgical planning, consulting a radiologist before image acquisition is important to achieve the optimal results. In addition to protocol, other adverse factors impeding a successful acquisition will need to be considered including motion artifacts, metallic or bony streak artifacts, sub optimal contrast opacification, and unusual body shape and size. [Ref]
b. File Manipulation
DICOM and WG-17
DICOM®, also known as Digital Imaging and Communications in Medicine, is the international standard for medical images and related information. It defines the formats for medical images that can be exchanged with the data and quality necessary for clinical use. DICOM® is recognized by the International Organization for Standardization as the ISO 12052 standard.[Ref]
Almost all the acquired radiological images, such as MRI, CT, Xrays and etc, follow DICOM® standard. Lately, the standard extends into ophthalmology and dentistry. It is important because DICOM® images are the source data for any 3D technologies, ranging from 3D printing to augmented and virtual reality. [Ref]
DICOM® is first published in 1993. In 1998, WG-7 3D (“Working Group 17”) was established to focus on a variety of 3D technologies using DICOM images as source data. [Ref]
During segmentation, a particular region of clinical interest is outlined/selected on each image based on pixel information to construct a three-dimensional object. This region of interest (ROI) can be a complex anatomical structure or particular pathology that needs to be surgically treated. This process can be both semi-automated and manually performed. Often, practitioners use a combination of both to achieve a final satisfactory 3D object. This is the most time consuming and laborious step, and lately, many startups and researchers are using artificial intelligence to optimize this step.
DICOM to STL file conversion
While medical images are stored as DICOM, most 3D printers only recognize certain file formats, most commonly, stereolithography (SLS) or Standard Tessellation Language (STL) files. It is the most accepted standard file format that interfaces between 3D software and 3D printers.
Traditionally, medical image Picture Archiving and Communications Systems (PACS) do not have the capability to perform the conversion to 3D printer file formats. However, there are many third-party software solutions to convert 2D images to 3D structures.
For example, the Mac-based DICOM viewer Osirix ( Geneva, Switzerland) is a widely used solution. Blender and 3D Slicer are well accepted free open-source tools. In terms of paid solution, Materialise Mimics and 3D Systems have FDA cleared solutions that received 510K clearance for 3D printing anatomical models.
In addition, more and more major PACS vendors such as GE and Siemens are updating their systems to include this functionality in their future versions. Soon, it will be a standard package when purchasing a scanner.
File optimization for final print (Mesh correction)
Along with the common 3D printable files such as STL, there is associated surface geometry in the form of connected triangles. This geometric information is also known as a “mesh”. The mesh must be mathematically continuous (“manifold”) to be ready for physical 3D printing. (3) This involves meticulous mesh correction steps to fix these geometric “errors” without losing significant anatomic accuracy. With a few exceptions (e.g. inkjet technology), a mesh with discontinuity (“holes”) cannot be printed.
c. 3D Printing
This step will construct the physical object based on the corrected mesh. This could be a single-step or multi-step process depending on the size and complexity of the digital design. Lately, researchers are working on further automation of the 3D printing process using machine learning and artificial intelligence.
After the object is printed, it is often necessary to remove the residual material or supporting structures. Post-print polishing, coloring, reconstruction, or material hardening (infiltration) may also be necessary depending on the use of the print. [Ref] Two notable startups that provide post-processing technologies are DLyte and Post-Processing Technologies.
Errors can occur during each of the previously described steps. Accumulative errors can be significant. There are a few suggested existing validation/quality control processes, but in general, this is an area of active investigation and improvement. First, the practitioner, preferably a radiologist or specialty imaging expert can compare the final mesh with the initial imaging study before the file is printed. Second, the surgeons can obtain intra-operative measurements and compare those to the 3D printed object. Third, practitioners can re-image the 3D printed object and compare the images with the patient’s images for differences. Others have also developed phantoms to validate the accuracy from digital design to physical print [Ref].
C. Values and Limitations of 3D Printing in Hospitals
Traditional manufacturing methods, like the drill press, lathe, or milling machine, need to be operated by the maker. The work piece needs to be aligned, measured, and machined by the user, which introduces human error into the making of the part. In contrast, 3D printing is a hands-off manufacturing process; just by pressing a button, whatever you design will be made.
Benefits of 3D Printing
The benefits of using 3D printing over traditional manufacturing make it suitable for situations requiring:
- Rapid prototyping
- Mass customization (e.g. Invisalign)
- Decentralized manufacturing enabling a more flexible supply chain and potentially further a decentralized healthcare delivery system.
- Lowering distribution and inventory costs (Post of care 3D printing)
- Complex geometries that
- Cannot be manufactured by any other method.
- Have improved material property (e.g. strength, elasticity, transparency).
- Can be manufactured more cost-effectively with 3D printing.
Limitations of 3D Printing
3D printing also has some current limitations that may not lend it to some applications:
3D printers can take hours rather than minutes to complete a piece and thus do not lend themselves to mass production for certain applications, especially in emergent surgical cases. Lately, faster and newer printers are now on the market, but pricing and material limitations create barriers. A majority of hospitals and clinics still rely on extrusion-based 3D printers using thermoplastics as bread and butter starting hardware.
The limited selection of 3D printing material, especially those deemed suitable for medical use (i.e. biocompatible, sterilizable, of good strength, multi-color, and affordable), hinders broader application.
3. Size Limitation
The size of the objects intended for printing also limits applications, as printers capable of making larger prints are more expensive and there are fewer options available. In addition, larger prints may take a significant amount of time to print, which would not be acceptable for clinical cases with time constraints.
4. Mechanical Properties
Final printed object mechanical properties can be inconsistent due to different printing orientation.
D. 3D Printing for Pre-Surgical Planning
Currently, the three main pre-surgical applications using 3D Printing include:
- Pre-surgical planning, including strategy development through improved ability to simulate and manipulate models.
- Creating anatomical models with haptic feedback. [Ref]
- Improving communications among multidisciplinary clinical care providers and between clinicians and patients.
These cases can be categorized into the following areas:
- Surgical strategy development: e.g. surgical approach, device selection, surgical tool selection [Ref, Ref, Ref, Ref, Ref, Ref, Ref, Ref]
- Surgical guides [Ref, Ref]
- Patient/patient family education [Ref]
- Education or training tool [Ref, Ref]
For each case, provider must ask ,”Does 3D printing add value in addition to conventional imaging and existing virtual planning tools?”
For the medical community to fully embrace a new technology, supporting evidence based on rigorous scientific methodologies is required. Recent examples of adoption of emerging technologies in healthcare include functional MRI, computational simulation, robotic-assisted surgeries. For each of these technologies, collection of clinical evidence was necessary not just for patients and clinicians, but also for the payers to fund their use.
In the past several years several major academic institutions such as the Mayo Clinic, Cleveland Clinic, Boston Children’s Hospital, and Stanford Healthcare have taken the lead. Collectively, these academic centers made significant advancements in exploring 3D Printing through clinical trials with larger patient populations.
Popular software and hardware companies like Materialise, Formlabs, Ultimaker, Stratasys, and HP have worked together in creating a workflow for point-of-care 3D printed anatomical models (Mimics InPrint Certification Program).
Most trials, publications, and advancements have occurred in the fields of orthopedics, pediatric surgery, and maxillofacial reconstruction surgery. We will explore the topic of “clinical trials” more extensively in part two of this Guide.
These studies serve not only as meaningful metrics of clinical outcomes, but also inspire future study design and technique with establishing tangible workflows.
Throughout this guide, we will provide real-life examples based on the academic publications and direct expert interviews. We are also embedding clinical examples with our Instagram posts. since this is a dynamic ever-changing field where creativities thrive.
E. 3D Printed Implants
As I have mentioned earlier, to have sustainable solution for both healthcare and the 3D printing industries, there are two emerging initiatives:
1. Production friendly solution
2. Point of Care delivery.
Finding the perfect applications that are in alignment with these directions will make financial sense for both sector.
A 3D printed implant, especially those manufactured at or close to a hospital, seems to fulfill both criteria. In the last few years, entrepreneurial and research activities are mainly in metal and PEEK based 3D printed implants. This trend is also in alignment with recently published data by FDA researchers in terms of FDA-cleared 3D printed medical devices.
For example, in 2019, Lima Corporate, a metal 3D printing orthopedics implant manufacturer, and Hospital for Special Surgery, an orthopedics specialty hospital created a facility close by the hospital, so that on-demand complex implants can be produced at the point of care.
Similarly, in 2019, Stryker teamed up with multiple organizations in Australia for a project called “Just in time implants”, where on-demand patient-specific implants can be produced for the patient after bone tumor resection.
In a different model, hospitals or healthcare providers act as device manufacturers and create facilities within the premise of the hospitals or clinics. For example, startups such as Kumovis and Apium both provide point of care 3D printers that can manufacture PEEK implants. The role of hospitals as a manufacturer is somewhat intimidating without a clear regulatory landscape.
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About the Author:
Jenny Chen, MD, is currently the Founder and CEO of 3DHEALS, a company focusing on education and industrial research in the space of bioprinting, regenerative medicine, healthcare applications using 3D printing. Dr. Chen holds degrees in both medicine and radiology from the David Geffen School of Medicine at UCLA and completed fellowship training in neuroradiology at Harvard Medical School. She currently serves as Adjunct Clinical Faculty in neuroradiology at Stanford University Medical Center. With a focus on emerging healthcare technology, Jenny invests in relevant startups and also serves as a startup mentor. Her investment focus is companies pitching through Pitch3D. She believes a more decentralized and personalized healthcare delivery system will be in our future.
3DHEALS Guides (Collective) – This is where we dive deep into subjects that you will find helpful for your projects and career.
3DHEALS From Academia (Collective) – This section features recent, relevant, close to commercialization academic publications in the space of healthcare 3D printing, 3D bioprinting, and related emerging technologies.