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MEDICAL & HEALTHCARE
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Rapid Prototyping or RP has many applications in the healthcare, medical, and research areas. Healthcare organizations worldwide increasingly rely on 3D anatomical models for pre-operative planning, specialist consultation, implant fit and design, patient counseling and medical education. Utilizing specially developed software, CT and MRI data are optimized for output in high-definition on 3D printers that produce full-color models in only hours. Below are a few examples of applications and how they help in developing solutions to real world problems.
Medical Devices and Tools
3D printing gives medical device makers a cost-efficient way to perfect the design of highly specialized tools and instruments before they're cut from stainless steel or other materials. Manufacturers use Rapid Prototyping to improve the ergonomics of instruments and collect real world data from surgeons and health professionals to assist during the development phase of instruments. Printed models are easy to finish and tough enough for functional testing in clinical situations. Rapid prototyping is used to aid in the conception and design of larger equipment and machines. They are popular with medical device engineers because a 3D model can approximate the injection-molded plastic of final products.
Beyond medical devices, 3D printing can be used to model human parts. CAD models based on CT scan data can be output through a 3D printer. The result is accurate 3D models of internal organs that guide surgeons through complex procedures.
Journal of Craniofacial Surgery
Use of Three-Dimensional Medical Modeling Methods for Precise Planning of Orthognathic Surgery
Medical Applications of 3D Prototyping
3DP, SLA and SLS technologies enable doctors & surgeons to rapidly create 3D models to gain better case information in order to reduce operating time, enhance patient - physician communication and improve operative outcomes. For the first time, doctors, nurses, and technicians who have no previous experience with 3D modeling or 3D printing can create 3D anatomical models from MRI and CT scan images quickly and easily.
Clear communication between physicians and patients is a critical factor in successful surgical procedures. Clear communication enables patients to make well informed decisions about their own medical treatment. 3D solid models are invaluable as a tool in improving the doctor – patient relationship.
Applications include pre-surgical planning, implant pre-contouring, custom implants, practitioner communication, presentation tools, student/resident education, and prosthesis design.
Pre-surgical planning
The ability to use 3D models for planning of surgical procedures reduces O.R. times, eliminates spurious costs, and enhances patient outcomes by minimizing incision sizes, reducing time to recovery and allowing for rehearsal of procedures.
There are several advantages to using RP in surgery. Using computer tomography (CT) scans, models can be built of a patient's bones. The models can be used to practice complex procedures, greatly reducing the time in the operating room. Not only can they be used to practice surgeries, but to aid in visualization. Surgeons and their teams will be able to see the actual location, size and shape of the problem area. This will aid in communication between the surgical team, and the physician and patient. In the case of extremely long operations, the surgical team can use the physical models to plan the surgery so that the desired outcome is more ensured. Surgeons can view the expected outcome and decisions can be made for the patient's short and long term treatment. Bio-modeling allows surgeons or surgical teams to prepare for non-traditional techniques and/or surgical procedures. This can be especially beneficial in surgeries where there are anatomical abnormalities involved.
Implant pre-contouring & custom implant manufacture
3D solid models facilitate the fabrication of custom implants rapidly and cost effectively for the ultimate in patient performance. Using RP to make implants is an alternative to standard implants. Some of the time and effort efficiencies that be realized include:
- Screw selection & location
- Screw trajectory
- Instrument selection
- Technique rehearsal
Precise implant fitting is absolutely crucial for the patient’s long term well-being.
Models can also be used for pre-surgical implant fabrication, where the model serves as a master from which the implant can be copied. This will allow for an accurate implant fit rather than the use of standard implant sizes. It is difficult to use CT images or x-rays as guides for the preparation prior to surgery of implants.
The conventional method for inserting an implant is to grind a standard implant before surgery, and during surgery to customize the implant for the individual. (#1) A patient may be left on the operation table for hours and is put at risk for surgical complications. With the aid of RP, surgical implants have become more accurate and surgery time has been significantly reduced. Implants are automatically made to fit, thus less time is wasted trying to do this during surgery.
(#1. Ramos and Stemper. A Medical Applications of Rapid Prototyping.@ Undergraduate Research Experience in Solid Free Form Fabrication. Milwaukee School of Engineering. 1997.)
Inter physician communication
3DP models enable better communication between physicians and surgical teams. This is particularly useful in multi-disciplinary cases. Surgical teams and specialists can coordinate healthcare efforts better by properly planning treatment and surgical strategies through the manipulation of 3D prototype models and the discussion of methods in which treatment can be coordinated.
Doctor-patient presentation tool
For most patients, the language of the healthcare professional may be difficult to understand. Having no medical background patients can’t read an X-Ray or MRI image and understand its implications. 3D models enhance the physician’s ability to communicate with patients; allowing them to more easily convey their diagnosis, thus raising confidence in the surgeon’s abilities and the likelihood of a successful outcome.
Medical student/resident education
3D models prove very useful in communicating with students and residents. Complex 2D images can be converted into easy to understand 3D models that can be held and easily manipulated for a more complete understanding of the anatomy.
Teaching aids and simulators
RP models can be used to make models of a given part of the body, a defect or other medical condition. These models can be molded and used by researchers or in classrooms. Better illustration of anatomy is achieved with these models and allows viewing of internal structure. Models can be distributed in kits to schools and museums for educational and display purposes. Medical students can use 3D models for anatomical studies and to practice surgical procedures without causing discomfort to an actual patient.
One other potential for these RP models is the use in teaching simulators. The models would give accurate representations of human anatomy. Simulators could provide a model of the ribs and sternum for proper location of heart sound or placement of ECG leads. Models of the trachea and esophagus could be used in a teaching simulator for the placement of tubes, such as a feeding tube or placing a vent. These simulators could be used in training of nurses and doctors or any other medical related field. By incorporating RP technology in training simulators, more accurate representation of the actual task can be obtained.
3D surface scanning and custom prosthesis design
Using 3D surface scanning technology a custom prosthesis can be fabricated from 3D models. The process begins with a 3D scan of the surface to which the prosthesis is to be applied. A rapid prototype is produced incorporating a patient's specific alignment characteristics. This rapid prototype is used as a pattern for making the prosthesis.
By using RP technology, the number of times that a prosthetic has to be refitted is decreased, thus cutting down on the overall cost. The creation of leg prosthesis in the traditional method starts off with a plaster wrap to the residual limb to make a plaster casting. This casting is later filled with plaster to make a positive pattern for molding the prosthetic socket. However, there are problems in using this standard method. Bony prominences must be accommodated by the prosthesis, and weight-bearing segments of the socket need structural reinforcement. With the aid of RP, the prosthesis uses an internally developed CAD system and a proprietary interactive CAD program to develop a biomechanically correct geometry that improves the fit, comfort, and stability.
Mechanical Bone Replicas
Rapid prototyping can be used to replicate mechanical characteristics and material variations in bone. A composite structure built with a lattice structure of SLA can create two distinct regions with properties similar to cortical and trabecular bone. Normal, pathological, and surgically altered anatomical bone can be illustrated. Non-homogenous variations within a region can also be modeled. Mechanically correct bone replicas can be used to test bone strength under given conditions. Additionally, an event could be recreated and the fractures, stresses, and other related changes on the bone can be observed or measured.
Anthropology
Anthropologists have discovered that RP can be very beneficial in the replication of bones and other artifacts. RP allows for the replication of artifacts so that molding, measuring and dissecting of the remains can be done without causing harm to the original finding. In cases where there may only be one or two specimens existing, it allows the original model to be safely locked away without hindering research done on the specimen. By taking CT scans of the object, it is easy to accurately recreate an artifact on RP machines. The CT scans are converted into STL files for building. An STL file is surface representation of an object made up of triangles and is compatible with RP machines. The models that are built can also be used to show changes with evolution.
Forensics
Homicide Investigation teams use rapid prototyping to reconstruct crime scenes. RP models help provide answers to some questions. Replication using RP is accurate enough that effects of wounds may be seen. Accurate predictions of the forces, implements and other key events in the crime can be determined using these models. There are cases where this has been especially helpful because the victim is still living and forensic teams cannot access the actual skull with fractures or injuries from the event. RP allows the production of bones, such as the skull, so actual physical models can be used in court.
In murder or wrongful death cases, models of the victim’s injuries are used to prosecute the perpetrator. These models would help recreate the scene in the courtroom as well as shine some light on what really happened.
Case Examples
Maxillo-Facial Surgery Mandible Reconstruction
Pre-contoured mandible plate Reduced time in the O.R. by 45 minutes.
Dr. Fernando Urrutia, Plastic Surgeon, Clinica Olinda, Mexico City, Mexico
Orthopaedic Surgery – Acetabula Reconstruction
Pre-contouring acetabula fixation plates
Can reduce O.R. time by as much as 2 hours
Incisions can be reduced from over 12” to as little as 4” in some cases.
Dr. George Brown, Chief, Division of Spine Surgery, University of New Mexico Health Science Center, Albuquerque, NM, USA
Custom Implant Manufacture
Silicone septum implant was constructed and fit to the 3D model saving 1 hour of O.R. time
Dr. Fernando Urrutia, Plastic Surgeon, Clinica Olinda, Mexico City, Mexico
Molecular Modeling
Research institutions and pharmaceutical companies involved in drug research and development, and Educational Institutions teaching the function and interaction of proteins and drugs on the molecular level, have a clear need for molecular models in real physical space.
Complex Geometry: Visualization and understanding
Visualization and understanding of the geometry of and interaction between complex molecules is extremely difficult using 3D visualization or renderings. According to Art Olsen at the Scripps Institute, “Chemistry is about shape and geometry. To physically interact in real space with molecules provides complete information and new insights. Leading researchers that have been working with a protein or molecule for ten years will immediately learn something new when they hold the molecule in their hand.”
The 3DP Model Solution
Full Color Models - 3DP (Three Dimensional Printing) is the only technology that can create full color models directly from digital data, representing electrical charge or atomic compositions in full color.
Real Space Interaction - At PROTOFACTURING we can quickly and inexpensively produce dozens of iterations of molecules that can then be physically manipulated to help understand their interaction. The ease and cost-effectiveness of our service makes it possible to use 3D physical models as a routine working medium.
Hybridized Models for Process Visualization and Training – 3DP models and other elements can be combined to provide a more complete picture of the behavior of the molecule being studied. A hands-on understanding is critical to an efficient learning process.
All the models above were produced with RP-Rasmol. RP-Rasmol is the tool used to translate a PDB file into an STL or PLY (color) file that is compatible with the 3DP printing process.
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