Distance Education Technology for
Prosthetic CAD/CAM Instruction
Edward D. Lemaire, MSc
ABSTRACT
A 96-hour course was created to instruct
prosthetic and orthotic clinicians on
computer-aided design/computer-aided
manufacturing (CAD/CAM) principles
and techniques. This course was presented using distance education technology to link the instruction site (Toronto,
Canada) with the student site (Ottawa,
Canada).
Through interactive computer graphics and standard telecommunications,
course participants studied the Chasidim, CANFIT-PLUS, Shapemaker
and University of Texas CAD/CAM
systems. A qualitative evaluation of
each software package was submitted
by each participant during course evaluation. This education method was endorsed by course participants and instructors as a viable technique for clinical CAD/CAM instruction.
Key words: CAD/CAM, education, telecommunications
Introduction
Computer-aided design/computer-aided
manufacturing (CAD/CAM)-a production technique-will considerably affect the field of prosthetics and orthotics
by influencing the way prostheses are
manufactured and indirectly affect present socket design procedures (1 ,2).
These technological and clinical developments have created a demand for education in this fast-paced environment.
Due to the infancy of CAD/CAM systems in prosthetics, educating clinicians presents difficulties that do not exist in other computer-oriented areas. Relatively few prosthetists have a substantial amount of clinical experience with CAD/CAM systems. This number may be even smaller with experience in teaching a variety of CAD/CAM products is considered. The shortage of qualified instructors makes it difficult to communicate specific information throughout the field.
The large distance separating prosthetic centers in Canada complicates the dissemination of information and techniques. This difficulty is augmented by the high costs of centralized education (i.e., travel, accommodations, course fees, etc.) and the amount of time required to teach new computer-related concepts.
The high cost of CAD/CAM hardware and software makes implementation of a complete course difficult in most regions; however, facility owners who plan to purchase CAD/CAM systems would benefit greatly from courses covering available software and hardware technology. Staff education would also make the transition from conventional techniques to CAD/CAM techniques much smoother.
To deal with these educational issues, George Brown College of Applied Arts and Technology (GBC) in Toronto, Ontario, developed a training program using distance education technology. This article will outline the principals behind the course, the training delivery process and the results.
Background
The CAD/CAM training program at The Rehabilitation Centre Ottawa, Ontario, Canada was developed from GBC's program. After successful introduction of prosthetic CAD/CAM systems in southern Ontario region, it became obvious a similar course was needed in eastern Ontario. In Ottawa area, institutional and private facilities were interested in installing CAD/CAM systems obtaining instruction on current technology.
Based on the previous CAD/CAM course outline, a revised curriculum of 96 hours was developed; however, various factors inhibited the application of this course:
- a lack of prosthetists who head substantial CAD/CAM experience in the Ottawa area
- 500km distance between The Rehabilitation Centre and GBC
- no prosthetic CAD/CAM hardware in the Ottawa area
To overcome these obstacles, long-distance education technology was suggested to connect prosthetists and computer experts in Toronto with course
participants in Ottawa. This system
would allow interactive visual and auditory communication between sites,
enhancing the presentation of the
course curriculum beyond present teleconferencing systems.
Once funding for this educational
project was obtained from the Ontario
Ministry of Skills Development, the
course presentation team was finalized
and class participants were identified.
Course instructors were from GBC and
the Sunnybrook Centre for Independent Living (SCIL). Course participants
consisted of O&P clinicians and technicians from the Rehabilitation Centre
and from local private prosthetic centers.
Course Outline
A 96-hour course was developed to instruct the participants in general computer use, CAD/CAM methods and
system specifics. The course was presented twice a week for 24 weeks. (The
class was split into two groups to maximize computer access time.) The
course was divided into three modules:
computer platforms, technology, and
computerized socket design and manufacturing.
Computer Platforms
Since most participants had limited or
no computer experience, Module I was
designed to teach computer basics for
IBM-compatible (MS-DOS) and Apple (Macintosh) systems. This section
covered items such as managing directories and files and running programs.
Module I concluded with a written examination on both MS-DOS and Macintosh. A 70 percent passing grade was
required before a student was allowed
to take Modules II and III. The evaluation was necessary to ensure a minimum competence level before introducing the various CAD/CAM systems.
Technology Today
The technology today module involved
an overview of prosthetic and orthotic
CAD/CAM developments, casting and
digitizing techniques, socket design using software, carving a positive mold
and mechanical socket forming.
Module II was initiated with a physical appearance by instructors. This
one-evening session involved a preliminary lecture on CAD/CAM procedures
followed by instruction in CAD/CAM
casting techniques. One subject with a
transtibial amputation was recruited
for each group of two students. The
instructors took the ensuing impressions to Toronto for digitization and
sent floppy disks containing the residual limb shapes to the teaching facility.
Digitized shapes were used throughout
Module II.
The remainder of Module II involved learning the basics of CAD
shape modification. CASDaM (ABT)
was used during this section because
the instructors had experience with this
product; the instructors considered the
software user-friendly; and carving and
socket-forming hardware were easily
available. This section concluded with
the participants creating a socket onscreen from their digitized casts. The
data files were sent to the instruction
site where the actual socket was produced. These sockets were returned to
the students by courier.
The participants finished their sockets and fit the result to the amputee
volunteers in a second, hands-on session. The instructors were present to
encourage feedback on CAD/CAM related elements of socket fit and function.
Computerized Socket Design
and Manufacture
Module III built on skills developed in
Module II by introducing other prosthetic CAD/CAM systems. Three lessons were devoted to CANFIT-PLUS,
Seattle Shapemaker and the University
of Texas System. These sessions focused on the skills required to modify a
residual limb shape and to create
standard modification tool, overlay
template. A digitizer was used during
this section to supply hands-on experience with cast digitizing and to create
socket data files for the CANFIT-PLUS software.
Through the assistance of VORUM
Research Corp., a positive model was
carved from the CANFIT-PLUS results; however, a positive was not created for the Seattle and Texas systems
Following Module III, participant,
were asked to evaluate each system
and suggest what parts of the course, if
any, they would change.
Equipment Requirements
The GTCS (Group TeleCommunications Software-IIS Technologies) system that allowed communication between sites required an IBM-compatible, 20-MHz, 80286 computer with
VGA graphics, a modem, a graphics/
digitizing tablet and an HP Laserjet II
printer to transfer visual images between sites. The printer produced hard
copies of handouts and forms. Audio
information was transferred using a
telephone with an external amplifier/
speaker. Two telephone lines were required for each session (modem and
voice).
The instructor's site had two additional devices, a document scanner and
a video camera. The video camera was
connected to the computer so single
video images could be digitized and
displayed on the screen at both sites.
This was useful for examining the results of socket modifications.
Table A
lists additional equipment
required for completion of the course.
All hardware was rented from local
sources.
Course participants used demonstration versions of all commercially available software (CANFIT-PLUS,CASDaM, Shapemaker, University of Texas).1,2,3,4 A copy of each software package was purchased and loaned to the
student site for digitizing and carving.
Communication Procedures
Efficient use of the GTCS environment
required the preparation of course
slides in advance. These slides consisted of images that were converted to
computer data files consistent with
GTCS requirements. The images were
obtained by either digitizing information on 8 1/2 x 11-inch sheets using document scanner, digitizing a video picture of an object, capturing a screen
image from an MS-DOS-based program, or preparing a slide using GEM
Draw or GTCS.5
Once the class materials were prepared, a copy of the image data files
was sent via modem to the remote location. Pre-shipping the image files was
essential to course efficiency since preshipment reduced the time required to
display the image on the computer
screen by more than 300 percent. (The
desired file could be displayed directly
from the remote computer without
waiting for the data to be transmitted
over the telephone lines.) Although
image pre-shipment is essential, the
ability to send video snapshots and pertinent documents between sites during
class time was invaluable for interactive participation.
After an image was displayed on the computer screen, instructors and students were able to interact verbally and graphically. By using paint-tools (pens,
rectangles, whiteout, erasers, typewriters, etc.), important areas of the image could be highlighted, areas not easily
described could be outlined, problem shapes could be drawn, etc. This graphical interaction is similar to methods used by football commentators to review a play. On television, the football commentator highlights key players, where they went and where they should have gone during the last play. For modifying prosthetic sockets, the
instructor uses the same principle on
the computer screen to outline an area
to be modified and draws the shape
after a general modification.
Although the GTCS system was
used for the majority of the course, the
instructors were present for hands-on
casting and fitting sessions.
ResultsCourse Evaluation
Students completed a brief questionnaire to provide feedback on course
content, instruction, length, overall
satisfaction and their ability to apply
the information. The results from this
survey are listed in Table B
.
The majority of participants were
very satisfied with this type of
educational initiative. More than 75
percent of course participants felt confident they could take the information
accumulated during the course and use
it in general practice. (Some participants commented that a two- to three-month trial period would likely be
needed).
Although all participants found the
course beneficial, the majority said the
course was too long. Further investigation showed that participants did not
need as much time to complete the lessons at the end of the course as the
instructors thought; consequently, latter portions of the course seemed
lengthy.
Initially, course length was based on
the time required for a noncomputerliterate person to learn how to use each
CAD/CAM system; however, after the
participants completed each successive
system, the time required to cover all
aspects of the software diminished
greatly. For future courses the amount
of time allocated for learning the first
CAD system should be maintained,
but the time allocation for subsequent
systems should be cut by up to 50 percent.
Course participants said the session
in which a VORUM (CANFIT-PLUS)
representative gave an on-site presentation provided considerable insight
into the CANFIT software. Future
courses could include presentations by
the software developers of each system
(on-site or over GTCS).
Participants also noted it would have
been beneficial to cast and fit patients
with each of the CAD/CAM systems
(as opposed to just the first system).
One way to offer this option would be
to digitize the same cast for each of the
CAD/CAM systems and allow the
prosthetists to fit the sockets on their
own time.
Standardization of data input between CAD products would facilitate
this process.
Product Evaluation
Upon completion of the course, participants were asked to define what they
liked and disliked about the various
systems. This evaluation is interesting
since feedback was obtained from novice and experienced computer users
who had little previous exposure to
prosthetic CAD/CAM systems. Such a
group acts as a good test for intuitive,
easy-to-use and effective software.
The results from this evaluation
were forwarded to the software developers and are summarized in Table
C
, Table D
, Table E
and Table F
. It should be noted these
are qualitative responses from the
course participants and do not constitute a specific research study with the
purpose of comparing CAD systems.
The number of responses for each section does not necessarily indicate preference.
Although the various software packages were functional, the hardware
configurations used for this course did
not always match up to the software
developers' recommended standards.
Performance enhancements should occur by following the developers' guidelines (more RAM, different graphics
card, etc.).
In response to the results in Table D
, VORUM Research Corp. (CANFIT-PLUS) made the following
comments:
- Redraw speed and shading capabilities are improved with the use of the
recommended hardware platform.
- The user can exit from the Region
Mods section in four places and from
the Other Mods sections partway
through the modification process.
- An undo feature currently works
with Regions and Overlays.
- A marker list for digitizing has
been added as a new feature for the
M + IND digitizer.
- A different rear flare can be added
by not applying the standard rear flare
and creating or modifying your own
overlay.
Conclusion
Distance education technology appears to be an ideal method for disseminating prosthetic CAD/CAM information. This technology permits prosthetists and computer specialists to
communicate with clinicians over any
distance, allows two-way communication between sites and could reduce
costs for long courses.
The participants were very satisfied
with the course, and the majority now
feel confident with this technology.
Based on this program, CAD/CAM
system purchases at the Rehabilitation
Centre can now be made with confidence and consensus.
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