RE: Scanners for Orthotic Fabrication (David E.
Gurvis, DPM)
From: Larry Huppin, DPM
I recently completed an evaluation and review of
9 digital imagers, including 5 optical scanners,
that is to be published in a upcoming orthotics
industry trade journal. Eight critical criteria
were found that scanners must meet in order to
produce a functional foot orthosis that provides
for optimum clinical outcomes:
Allows for standard neutral suspension cast
technique. Only this position allows proper
positioning of the foot, including the ability
to plantarflex the first ray. Note that it is
critical that the foot be non-bearing.
Pressure on the plantar surface, whether the
foot is semi-weight-bearing in a foam box or
pressing against the glass plate of an optical
scanner, will lead to excessive varus captured
in the cast/scan.
Allows the foot to be held with no contact on
the scanning unit. Pressure on the foot from
the scanning unit deforms the plantar arch shape
and has great potential to dorsiflex the first
ray. An orthosis made from an image where the
first ray is plantarflexed will act to prevent
first ray plantar-flexion and lead to functional
hallux limitus.
Captures plantar surface contours with plaster-
like accuracy. Studies on orthotic therapy for
metatarsalgia, hallux limitus, tarsal tunnel
syndrome and plantar fasciitis indicate that
total contact with the arch provides better
clinical outcomes. In order to conform close
to the arch, the image must accurately capture
the arch.
Captures the posterior heel to allow frontal
plane (forefoot to rearfoot) balancing. The
ability to balance the forefoot to the rearfoot
offers better potential clinical outcomes in
most of the primary pathologies commonly treated
with functional foot orthoses. Balancing
requires that the image of the posterior heel,
along with the plantar foot be captured in the
image. Unfortunately, this critical aspect of
the image is being ignored in many of the
imagers currently being marketed.
Cost and time effective.
High degree of reliability.
Effective support and service infrastructure.
Allows choice of multiple labs.
Only two scanners currently on the market fit
all of these criteria. These are the Sharp Shape
(Sharp Shape, Cupertino, CA) and Veriscan (
EnvisicVPS, St Louis, MO) units. Both scanners
provide images that fit all criteria and are as
good as plaster. I have used the Sharp Shape
scanner for virtually all orthotic casting over
the past 12 months and have been extremely
satisfied with the function of the unit,
software, orthotic outcomes and support from the
company.
These are both both small companies, however,
and I have concern that they may not have the
support infrastructure to reliably service
customers when they have many units being
utilized. My advice is wait at least a few
months before purchasing a unit - technology is
changing rapidly.
I do work as medical director for an orthotic
lab but I have no financial connection to any
company producing scanners.
Larry Huppin, DPM, Seattle, WA,
lhuppin@gmail.com
