Medical Applications

of Additive Manufacturing

Prof. Antti MäkitieHelsinki University Hospital and University of Helsinki

FIRPA Seminar

6.4.2011

Additive Manufacturing (AM)

within the medical paradigm

Additive Manufacturing (AM)

within the medical paradigm

AM is used as part of the manufacturing process

Integration of anatomical data into the product

Adaptation of design to suit an individual

Mass customization

Helps to make products fit and work better

Added value

Do the AM technologies differ?

Cost

Range of materials

Speed

Versatility

Ease of use

Layer thickness

Accuracy

Process chain and planning

Maintenance requirements and service

Why is AM so useful for

medical applications?

Used to represent specific patient data

Integrates well with CT/MRI

Layer-wise format

Can produce tactile models for surgeons

Improves spatial awareness

Can fabricate complex geometry

Integrates engineering and medicine

Problems with AM Speed

Not always fast enough. Ok for tissue engineering

Cost

Overhead costs for single components high

Helpful if increase in surgical efficiency can be justified

Accuracy

Initial requirements for accuracy were low (this is now changing)

Materials

Issues with contamination

Need to develop more biocompatible materials

Ease of use

Make technology safe, clean and easy to use

Additive Manufacturing (AM)

within the medical paradigm

Why should we classify?

Class-specific and case-specific

characteristics and requirements

Preoperative models

Medical aids, supportive

guides and prostheses

Tools, instruments

& parts for medical

devices

Inert implants

Biomanufacturing

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nen

Preoperative models

Medical aids, supportive

guides and prostheses

Tools, instruments

& parts for medical

devices

Inert implants

Biomanufacturing

Models for preoperative

planning,education and

training

The earliest medical application of AM

Planning or simulating a surgical procedure

Educating students, patients and family

Enhances spatial awareness

Permits viewing from any angle

Reduces ambiguity

Used in various stages of complex surgery

Treatment plans

Informed consent

Communication within the teams

Design template for prosthetics

Medical aids, supportive guides, splints & prostheses

Improvements in CT More precise imaging

More precise models

To provide patient-specific fit

Specific emphasis on prostheses AM’d piece placed external to body

Integrate medical data with engineering data

Integrate surgical simulation

Development of new medical products Drill-guides, orthopedic appliances and braces

Personalized splints

External prostheses

Tools, instruments & parts for

medical devices

To enable or improve the efficacy of a medical procedure

Patient-specific dimensions and shapes may be incorporated

Invasive but not implantable, sterilizable

Contact with body fluids, mucous membranes, tissues

No immediate toxicity or allergic reactions

No shedding of particles

E.g. surgical instruments, orthodontic appliances

Directly or indirectly Additive Manufactured (AM’d)

implant

Biocompatibility, strict material requirements

Long-term, durability, mechanical properties,

surface properties

Implant will not change its characteristics in vivo

May attract cell adhesion on surface but mainly

stays inactive

Includes dental app’s: crowns & bridges

Inert Implants

Orbital implant

Anatomical accuracy

Implantable material

Light but durable structure

Sterilization may not change

material properties

Polished, smooth surfaces

to prevent tear damage

Minimal heat conductivity

AM and Tissue Engineering

Direct manufacture of replacement organs

Both hard and soft tissue constructs “organ manufacturing”

Conventional method is to use a scaffold

Geometry and functionality

Material should be biocompatible and preferably bioresorbable or biodegradable, cell growth conductive

The scaffold should also encourage cellular regeneration both in vitro and in vivo

Polymers, ceramics and composites, porous structures

Shape of AM’d piece personalized to match tissue defect, optimal morphologies depend on cell type

Acknowledgements

Jari Salo, Jan Lindahl, HUS

Risto Kontio, Karri Mesimäki, Christian Lindqvist, HUS

Tuomas Klockars, HUS

Jyri Hukki, HUS

Risto Renkonen, HY

Anders Westermark, Karolinska Institutet

Yongnian Yan, Xiaohong Wang, Tsinghua University

Tekes, Planmeca, DeskArtes, EOS Finland, Hoffmanco

Consulting

Acknowledgements

Jukka Tuomi

Kaija-Stiina Paloheimo

Markku Paloheimo

Mika Salmi

Roy Björkstrand

Lotta Vihtonen

Eero Huotilainen

Juho Vehviläinen

Jouni Partanen

Xiaohong Wang

Yongnian Yan

Application Types of materials

Skeletal system:

Joint replacement (hip, knee) Titanium, Ti-Al-V alloy, stainless steel, polyethylene

Bone plate for fracture fixation Stainless steel, cobalt-chromium alloy

Bone cement Poly(methyl methacrylate)

Bone defect repair Hydroxylapatite

Oral implants Titanium, calcium phosphate

Cardiovascular system:

Blood vessel prosthesis Dacron, Teflon, polyurethane

Heart valve Reprocessed tissue, stainless steel, carbon

Catheter Silicone rubber, Teflon, polyurethane

Organs:

Artificial heart Polyurethane

Skin repair template Silicone-collagen composite

Artifical kidney (hemodialyzer) Cellulose, polyacrylonitrile

Senses:

Intraocular lens Poly (methyl methacrylate), silicone rubber, hydrogel

Cochlear replacement Platinum electrodes

Class Purpose Relation of AM'd piece to patient

Primary description Requirements Other

Preoperative models

Plan or simulate surgical procedure; Educate students, patients and family, train surgeons

No patient contact Based on patient geometry but magnification or miniaturization possible;

Anatomical accuracy requirements depend on case

Transportability, storability, behavior in process, haptic response requirements depend on case

Medical aids, supportive guides, splints & prostheses

Enhance healing from trauma, anomaly or defect

External to body –non invasive

May be combined to standard devices to provide patient-specific fit; Long term and postoperative supports, (motion) guides and fixators

Non-allergic if in contact with skin, mechanical and surface requiements depend on case

Includes external prostheses and prosthetic sockets, personalized splints, drill-guiding microtables, orthopedic appliances and braces

Tools, instruments & parts for medical devices

Enable or improve the efficacy of a medical or surgical procedure

Contact with body fluids, mucous membranes, tissues or organs for a limited time: Invasive but not implantable,

Patient-specific dimensions and shapes may be incorporated;

Sterilizable; No immediate toxicity or allergic reactions, no shedding of particles; mechanical and surface requirements depend on case

Includes drill guides, specialty surgical instruments, orthodontic appliances

Inert implants Tissue replacement Wholly or partly implanted, long term contact with body fluids, tissues or organs

Biocompatible; will not change its characteristics (much) in vivo

May attract cell adhesion on surface but mainly stays inactive; durability, mechanical properties, surface properties depend on case

Strict material requirements, long approval processes; Includes dental applications: crowns & bridges

Biomanufacturing

Biologically active tissue replacement; “organ manufacturing”

Incorporated into body

Shape personalized to match tissue defect, porous structures, optimal morphology depends on cell type and application site

Porous structures; Scaffolds must be cell growth conductive, inductive, resorbable, controlled

Polymers, ceramics and composites; Freeform culture media in vitro; Additive manufacturing + tissue engineering;