 |
A Call to Improve Advanced Science Content: Part II
By Edward S. Neumann, PhD, PE, CP Editor's Note: "The capabilities of any technical profession are
highly dependent on the quality of the science underlying it." With
this thought in mind, Edward S. Neumann, PhD, issued a call to
expand and improve the advanced science content of O&P
curricula in an article published in the July issue of The O&P
EDGE. In this issue he provides an in-depth examination of four of
the seven areas in which he feels upgrading and expansion are
needed. A discussion of the last three areas, along with Dr.
Neumann's recommendations and conclusions, will be published in the
September issue.
 Biomechanical Tissue Factors
Biomechanical tissue factors of importance include the
engineering properties of tissues, their composition, strength,
requirements for nourishment, and most important, how they respond
to load.
In my opinion, the development of classroom materials on tissue
properties and behavioral characteristics is one of the most urgent
needs in prosthetics education. The O&P practitioner purposely
applies external loads of a magnitude great enough to potentially
cause discomfort and necrosis to areas of the body that were not
designed to carry such loads. All practitioners should have
knowledge of the basic biomechanical concepts associated with, and
scientific work that has been conducted on, tissue loading and its
consequences.
With the proliferation of socket liners, materials, and
suspension technologies available in today's market, the
practitioner's ability to ask suppliers the right questions and to
develop informed judgments depends upon a basic understanding of
tissue biomechanics and physiology. Socket fit challenges created
by redundant tissue, edema, shrinkage, scar tissue, skin grafts,
and invagination should be analyzed from a biomechanical
perspective utilizing tissue property concepts. The relevance of
the concepts of shear force and the coefficients of friction
associated with different materials should be presented.
Candidate sources of content include: the classic book by S. W.
Levy, on Skin Problems of the Amputee; the series of articles by L.
Bennett on the effects of shear stress and the more recent work by
J. E. Sanders on this topic; the tissue properties and
finite-element modeling studies conducted by D. Childress, B
Silver-Thorne, S. G. Zacharia, W. M. Vannah, A. F. T. Mak and Y. P.
Zheng; and the classic studies on friction blisters undertaken for
the military. The biomechanical parameters, experimental
methodologies, and findings that appear in these studies, as well
as their limitations, should be distilled and presented to the
student.
The science of osteo-periosteal bone bridge techniques would
also fall within this category. Knowledge of tissue biomechanics
will become essential if prosthetic limb osseointegration
techniques are introduced in the United States. Radiography, the
most recent addition to the National Commission on Orthotic and
Prosthetic Education (NCOPE) requirements, might fit in the tissue
biomechanics category as well.
Theoretical models of socket pressure distributions for the
family of lower extremity prostheses were developed by C. W.
Radcliffe, and every student should be familiar with them because
they indicate locations within the socket where tissue tolerances
are most likely to be exceeded. Although a lack of reliable and
inexpensive socket pressure measurement systems for many years
limited research into socket biomechanics, a number of studies were
undertaken and published. Usually these studies examined tissue
properties. Recent advances in the state-of-the-art socket pressure
measurement may facilitate new studies that could expand upon the
earlier theoretical work and make pressure measurement a useful
everyday tool for the clinic. The tissue biomechanics category
offers considerable potential for advanced science courses.
Biomechanical Gait Factors
Biomechanical gait factors concern the effect of pathology and
component design characteristics on the kinematics and kinetics of
gait. Most curricula currently contain information on the analysis
of gait derived from research conducted by V. T. Inman, J. Perry,
and others during the last five decades. However, a significant
number of scientific studies have been conducted more recently
using sophisticated human motion analysis systems to examine the
effects of different prosthetic and orthotic component designs on
gait. These studies have been published in both the O&P
journals and medical and rehabilitation journals. Collectively,
these articles describe the state-of-the-art in gait measurement
and assessment in the context of O&P science and form a
universe of relevant concepts, research hypotheses, and conclusions
from which a subset could be extracted to serve as the basis for
educational materials.
A thorough review of these studies that points out the
differences among them with respect to variables controlled for,
variables researched, and findings, could lead to improved research
hypotheses and perhaps ultimately to better clinical tools for
assessing patient needs and characterizing the components being
marketed. Gait-related biomechanical factors also involve the
challenges created by level of amputation and limb length.
Physiologic Factors
Physiologic factors are related to the constraints created by
underlying pathologies, which may be the reason for amputation and
may also limit the activity levels of individuals via circulatory,
metabolic, or respiratory insufficiencies.
Some pathologies and the treatments for them create fitting
challenges by causing major volume fluctuations in the residual
limb, changes in blood chemistry, or a lack of sensation.
Components which require higher energy expenditures can conflict
with the physiologic limitations of patients who have circulatory
or respiratory disorders. A number of articles have been published
in the rehabilitation literature on the comparative energy costs of
different component designs, as well as the comparative energy
costs of different levels of amputation.
Students should be aware of the energy cost implications of both
amputation level and component selection, because they can
influence outcomes among geriatric patients as well as highly
active individuals. The published articles are a good source of
information on the relevant concepts from exercise physiology, the
variables involved and their relationships, and the magnitude of
the impact that can be expected from alternative component
designs.
Psychophysical Factors
Psychophysical factors involve the neurophysiologic mechanisms
by which sensations are produced and evaluated to form judgments of
discomfort.
Important subjective phenomena include sensations of pressure,
tightness, heaviness, temperature, moisture, and pain. Knowledge of
the neurophysiology underlying pain and pressure sensation can help
the clinician to better interpret the discomfort symptoms of
patients, and should therefore be viewed as essential to clinical
practice.
Although psychophysical phenomena have been overlooked in
O&P research, the patient is very much aware of their
importance. Ergonomic science has established that psychophysical
phenomena underlie many of the judgments individuals form with
respect to the maximum amount of applied force and level of
exertion they can tolerate; frequently these subjective judgments
do not agree with tolerance levels predicted purely by
biomechanical or physiologic models. O&P science should
introduce the student to the basic concepts and measurement methods
of psychophysics, and indicate its relevance to clinical
practice.
Edward S. Neumann, PhD, PE, CP, professor of Civil and
Environmental Engineering at the University of Nevada, Las Vegas
(UNLV), is currently involved in efforts to establish a degree
program in biomedical engineering at UNLV. He is developing and
teaching courses in prosthetic systems, assistive technology, and
ergonomics. 
 |
OSU-Okmulgee Announces O&P Technician Program
- October 2006
Feature
|
|
|
The Orientation of a Homing Pigeon
- October 2006
Feature
|
|
|
Northwestern Survey Identifies Research Priorities
- October 2006
Feature
|
|
|
Exciting Vision for Practitioners in the Future
- October 2006
Feature
|
|
|
O&P Ascends Professional Summit
- October 2006
Feature
|
|
|
Is O&P Education Doing Its Job?
- September 2006
These words sum up the paradigm shift sweeping through US healthcare, including the educational field. Orthotics and prosthetics too is running with the tide, and is in fact, ahead of the wave, according to Robin Seabrook, executive director of the National Commission on Orthotic and Prosthetic Education (NCOPE)
|
|
|
Advancing O&P Education: How Are We Doing?
- February 2004
In talking with educational experts and O&P professionals closest to the subject, one can't help realizing that there is "buzz," enthusiasm, anticipation, positive energy--and above all, there is real PROMISE in the record of what's been happening recently and what's going forward already in 2004 with regard to O&P education.
Feature
|
|
|
Distance Learning: A New Era In Orthotic/Prosthetic Education
- June 2003
Education Outlook
|
|
Table Of Contents - August 2002
|
|
