3D printing has the potential to profoundly impact medicine through rapid prototyping techniques. The document discusses using 3D printing to create accurate, life-sized anatomical models from patient medical imaging data for use in surgical planning, rehearsal, and education. This improves surgical efficiency and outcomes by better representing complex patient anatomy. While promising, challenges remain regarding material properties, validation, sterilization and other factors for medical use of 3D printed models.

1. Body + Bits = Build
3D Printing for Surgical Innovation;
Rapid Prototyping for Personalized
Medicine
Nigel M. Parsad
Art of Science
November 13th, 2014

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Will 3D Printing Change the World?
• “…may have as profound an impact on the world
as the coming of the factory did.” The Economist (2011)

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Maybe?
• “3D printing is a strange meme that is being
misrepresented in the press by people who
don’t actually use it.”
Neil Gershenfeld, MIT Center for Bits and Atoms (2013)
• “…the 3D printer could create a new nimble
industrial era of individualised, localised
goods escaped from the grip of huge
manufacturing companies with vast capital
investments and cumbersome making and
delivery processes.”
BBC Business (2013)
• A Non-Industrial Revolution?

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Rapid Prototyping
• Rapid prototyping (RP) is a design and
fabrication process where 3D objects are
“drawn” using software (CAD) and “built’”
using digital manufacturing (CAM)
• 3D printing (3DP) is an example of additive
layer digital fabrication
• Contrast this to digital subtractive
fabrication such as CNC milling
• Unlocks creativity & innovation & Promotes
a patient-centric focus for medical modeling

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Rapid Prototyping: Bioprinting
• Goal is to restore, maintain, improve and/or
replace tissue or whole organs
• 3DP of living (stem) cells in scaffolding
support structure as opposed to non-
organics, i.e., metals, rubber, polypropylene,
and plastic resins
• extensively interdisciplinary field involving
researchers versed in tissue engineering,
material science, CAD/CAM etc.
• 3D Bioprinters are still in the research
domain (Organvo claims to be first)

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(My) Rapid Prototyping: Surgery
• Anatomical regions of interest (ROI) are
segmented from conventional 2D medical
imaging (CT/MRI), not designed using CAD
• Every 2D medical image has a DICOM header
containing spatial metadata for each pixel
as well as the spatial relationship between
and order of images in a scan dataset
• Volumetric reconstruction, visualization
and ROI segmentation of voxel data from
pixel data is often desirable before 3DP

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Problem: Anatomy is Challenging!
• Human anatomy demonstrates complex 3D
spatial relationships with unique variability
between patients
• With conventional 2D medical imaging and
generalized medical illustration (Gray’s
Anatomy), crucial depth cues are lost
• Cognitively compensating for this lost
spatial dimension may increase operating
time…a potentially bad metric for patient
outcomes

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Solution: 3D Visualization & FabLab
• We Locally design and manufacture
anatomically accurate models from
standard medical imaging. This is a
significant surgical innovation
• engineer and validate end-to-end rapid
prototyping workflows utilizing image
segmentation techniques, 3DP hardware
and 3D stereoscopic visualization
• clinical use cases include anatomical
models for surgical rehearsal, simulation,
education and intra-operative use

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Proof of concept 1: Mandibular
Transplant
• Plastic surgery requested the segmentation
and fabrication of an anatomically correct,
life-sized model of a patient’s mandible
derived from the patient’s CT data
• The mandible model was used for surgical
rehearsal and compared to actual patient
anatomy during facial reconstruction
surgery

10. RP Workflow: CT Scan to Print
Volumetric+reconstruc.on++
Segmenta.on+++++++CAD+model+
3D+Fabrica.on+using+Objet+
Connex+350+++post@processing+
1.+ 2.+
Compare.+Iterate+if+necessary+3.+ 20#30%%minutes%saved%in%Surgery%%4.+

11. Rapid Prototyping for Personalized
Medicine

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Proof of concept 2: Patella
Dysfunction
• Orthopedic Surgery requested an accurate,
life-sized anatomical model of a patient’s
left knee derived from CT imaging
• Surgical team rehearsed the orthopedic
procedure on the 3D print prior to surgery
• The tools and techniques used in rehearsal
were duplicated in the operating room

13. Proof of concept 2: cont’d.

14. Proof of concept 3: Spinal Scoliosis

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RP Algorithms of Note
Vanek, J., Galicia, J. A. G., Benes, B., Měch, R., Carr, N., Stava, O. and Miller, G. S. (2014),
PackMerger: A 3D Print Volume Optimizer. Computer Graphics Forum, 33: 322–332.
Rypl D. and Bittnar Z., (2006), Generation of Computational Surface Meshes of STL
Models. Journal of Computational and Applied Mathematics, 192: 148-151.
G-code (RS-274) numerical Control (NC) Programming Language translates planar
intersections with polygonal meshes to create CNC tool paths (often proprietary)
(1). Any GPU volume Rendering + OpenGL/OGSL Paper in the last decade…
(2). GPU Gems 3
(3). A good medical physics textbook
(1). The Visualization Toolkit (VTK)
(2). Insight Segmentation and Registration Toolkit (ITK)
Optimization of Object Orientation, Material Percentage, Slicing, Mesh Size (# of
Triangles)…

16. Entropy of 3D Fabrication
Information
Content
Computational
Complexity
BITS2BODY
Anatomy (3D Object)
Medical Imaging (2D Slices)
Virtual Anatomy (3D Object)
3D Print
(2D Slices)
3D Mesh
(3D Object)
Heat Death
of the
Universe
Whiteboard Scribble 00
Time (∆t)

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Conclusion
• Introduce advanced 3D visualization and
fabrication paradigms for the the accurate
modeling of patient specific anatomy, i.e.,
rapid prototyping for personalized medicine
• Increases effectiveness of surgical
planning and application by improving
operative efficiency and cognitive
awareness, i.e., measure twice, cut once
• Potential time reduction in the OR
• Potential for better patient outcomes

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Future Considerations for Medicine
Pre-Printing
• Material Chemistry
• Physical Properties
• Recyclability
• Reproducibility
• Process Validation
Post-Printing
• Removing/Minimizing
Excess Material
• Sterilization
Effectiveness on
Complex Shapes
• Biocompatibility
• Verification of
Design Envelope
Printing
• Production Cost/Time
Effectiveness
• Commercial Software/
Hardware Robustness
and Pricing
• Commercial Software/
Hardware Availability
• Fabrication Quality
Control & Standard
Practices

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Thank You!
Bits2Body.com
web email
Bits2Body@gmail.com