Northwestern University Feinberg School of Medicine

Northwestern University Prosthetics-Orthotics Center

Development of a Low-Cost Dilatancy-Based System for Orthotic Fabrication (FO, AFO, KO, KAFO, TLSO)

Principal Investigator: Yeongchi Wu, MD,

Co-Investigators: Steven A. Gard, PhD; John Michael, MEd, CPO/L

Research Orthotist: Christopher Robinson, MS, MBA, ATC, CPO/L, FAAOP

Research Assistant: Larissa (Conner) Sletto, CO

Consultant: Hector Casanova, CP/L

Funded by: National Institute on Disability and Rehabilitation Research (NIDRR) Field Initiated Grant Number H133G110266

Status: Completed

Dilatancy casting of orthoses

Videos about Dilatancy Fabrication
See video in .avi format: Close-up of Dilatancy-formed Negative Polystyrene Mold
See video in .avi format: Realignment of a Positive Sand Model

Purpose

The purpose of this proposed development project is to create a dilatancy (vacuum-based) system that will enable low-cost and rapid fabrication of orthoses. Previously, we developed a dilatancy casting system (i.e., CIR Casting System) for prosthetic socket fabrication with funding from the NIDRR RERC on Improved Technology Access for Landmine Survivors (1998-2008). This system has been adapted for fabricating more than 3,000 prostheses in India and Thailand.

The project goal is to design and evaluate an orthotic dilatancy casting system for capturing the impression of a body part in order to fabricate a custom orthosis biomechanically individualized for the person with disability. This system would replace the conventional method of taking impressions using plaster bandages. The primary target population will be trained orthotists who provide services to individuals with disabilities.

The objectives of this project are to develop and evaluate orthotic dilatancy technologies during a three year project in four stages:

1) Design and Laboratory Testing Phase: Develop equipment and procedures; and conduct laboratory testing on positive plaster models.2) Clinical Evaluation Phase: Conduct clinical evaluations of new orthotic fabrication system on research subjects.3) Review and Demonstration Phase: Demonstrate new orthotic dilatancy fabrication systems to practicing orthotists and orthotics students to acquire feedback and suggestions for further refinement.4) Knowledge Translation Phase: Prepare detailed technical manuals for each validated orthotic dilatancy fabrication system for knowledge translation and hold workshops to train orthotists.

The orthotic dilatancy fabrication system will be developed in different stages, initially establishing procedures for smaller, simpler orthosis designs and progressing to those that are larger and more complex in the functions they provide. Efforts will be focused on five different types of orthoses that are commonly prescribed and fitted by orthotists: Foot Orthosis, Ankle-Foot Orthosis, Knee Orthosis, Knee-Ankle-Foot Orthosis, and Spinal Orthosis.

Like the previous prosthetic dilatancy casting system that we developed, it is expected that the orthotic dilatancy system will result in significant reductions in time, cost and waste materials produced compared with conventional means. As an alternative to both plaster-based and CAD-CAM-based approaches, we believe that orthotic dilatancy methods will be attractive within both resource-limited and health-care-cost-containment environments worldwide.

The project is consistent with NIDRR's Long Range Plan for the development of new knowledge and methods that can be translated through education and training conferences, courses or workshops to integrate development and practice to serve individuals with disabilities.

Related Presentations and Publications

Robinson C, Wu Y, Michael J. (2012) Development of a Low-Cost Dilatancy-Based System for Orthotic Fabrication: A Preliminary Report. AOPA National Assembly, September 9, Boston, MA.

Wu Y, Robinson C, Casanova H, Michael J, Gard S. (2012) The Low-Cost Dilatancy System for Orthotics. The Midwest Chapter of the Academy 2012 Fall Education Symposium, September 26, Lake Geneva, WI.

Wu Y, Robinson C, Casanova H, Michael J, Gard S. (2013) Development of a Low-Cost Dilatancy-Based Casting System for Fabrication of Ankle-Foot Orthoses: A Preliminary Report (Free Paper). The 14th World Congress of the International Society of Prosthetics and Orthotics (ISPO), February 4-7, Hyderabad, India.

Wu Y, Robinson C, Casanova H, Michael J, Conner L, Gard S. (2013) Demonstration of Dilatancy Casting for Transtibial Socket and Foot Orthosis: A Reverse Innovation of Appropriate Prosthetic/Orthotic Technologies. The Midwest Chapter of the Academy 2013 Annual Meeting and Scientific Symposium, June 1, Lake Geneva, WI.

Wu Y and Robinson C. (2013) Evolution of the Dilatancy Plaster-less P&O Technologies. Concurrent Education, the American Orthotic & Prosthetic Association (AOPA) World Congress, September 18-21, Orlando, FL.

Conner L and Robinson C. (2013) Dilatancy-Based Impression Technique for Foot Orthoses. Concurrent Education, the American Orthotic & Prosthetic Association (AOPA) World Congress, September 18-21, Orlando, FL.

Anderson R. (2014) NUPOC Scientists Bringing New Technology to Developing World. Feinberg School of Medicine, News Center, February 12. http://www.feinberg.northwestern.edu/news/2014/02/NUPOC_dilatancy.html.

Conner L, Robinson C, Wu Y. (2014) "Development of a Low-Cost Dilatancy-Based System for Orthotic Fabrication" (poster). The 10th Annual Lewis Landsberg Research Day, April 3, Northwestern University, Chicago, IL.

Wu Y with Walker R. (2014) A Priori of O&P Casting Technology. The Annual Georgia State O&P Meeting, April 3-5, Atlanta GA.

Wu Y with Peterson E. (2014) Plasterless Casting Techniques for O&P Applications (90-minute Workshop). The Annual Georgia State O&P Meeting, April 3-5, Atlanta GA.

Wu Y, Conner L, Robinson C. (2014) Dilatancy-Based Foot Orthosis Impression and Fabrication System (3-hour Course): Orthotists, Prosthetists, Pedorthists, Assistants and Technicians (2.75 Continuing Education credit available), May 17, NUPOC, Chicago, IL.

Wu Y, Conner L, Robinson C. (2014) Dilatancy-Based Foot Orthosis Impression and Fabrication System (3-hour demonstration-participation seminar): Class of MPO 2015 graduate students, October 25, NUPOC, Chicago, IL. 

Sletto L, Wu Y, Robinson C. (2016) Dilatancy-based impression and fabrication technique for custom foot orthoses. Prosthetics Orthotics International, 40(3):409-413. doi:10.1177/0309364615574162.

Wu Y, Sletto L, Robinson C, Casanova H, Michael J, Gard S. (2015) Innovative Dilatancy Prosthetic-Orthotic Technologies for Low-Income Countries. (poster). The 11th Annual Lewis Landsberg Research Day, April 3, Northwestern University, Chicago, IL.

Robinson C, Wu Y, et al. (2016) Dilatancy System for Orthotic Fabrication. 42nd American Academy of Orthotists and Prosthetists Annual Meeting & Scientific Symposium, March 9-11, Orlando, FL. 

Wu Y, Robinson C, Casanova H, Michael J, Gard S. (2017) Knowledge Translation of Dilatancy Socket Fabrication. (poster) 43rd American Academy of Orthotists and Prosthetists Annual Meeting & Scientific Symposium, March 1-4, Chicago, IL.