RESPONSES: Neoprene vs Silicone Gel Liner and Heat Insulation

RESPONSES: Neoprene vs Silicone Gel Liner and Heat Insulation

Dear O&P List Serve Members:
 
Many thanks to those who responded to my OANDP-L post with the helpful input
and information you provided. My original post and the responses are copied
below.
 
In summary, it appears there is not sufficient documented evidence, opinion
or experience to support the benefit of Neoprene or Silicone as the more
appropriate heat insulator to protect one's residual limb in cold temperatures.
 
The mere fact that any cover over one's residual limb would help to protect
it from cold temperatures, even including a heavy ply Cool Max type
prosthetic sock, which I did not mention in my post as a consideration.
 
Regardless, my plan at this point is to first utilize the least costly
approach, and possibly the best, by using a Cool Max type prosthetic sock before
attempting the more expensive silicone gel liner or neoprene approach, should
it not prove to be adequate.
 
Thank all of you again for your input and if find or receive anything more
of significance, I will pass that along to the Listserv.
 
John N. Billock, CPO/L, FAAOP

  
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 From: JNBillock
To: <Email Address Redacted>
Sent: 2/4/2009 2:13:09 P.M. Eastern Standard Time
Subj: Neoprene vs Silicone Gel Liner and Heat Insulation


Dear O&P List Members:
 
I am inquiring to see if anyone has had any first hand experience using a
silicone gel liner for thermal protection of an individuals residual limb in
cold temperatures vs possibly a custom neoprene liner?
 
My question is relative to providing an individual with a transradial upper
limb amputation a means of achieving thermal protection when not wearing
their prosthesis outdoors in cold temperatures.
 
Neoprene obviously has been used in wet suits for thermal protection in cold
water diving and other water sports, such as surfing, for years.
 
Regardless, silicone gel liners are more readily available for use on a
transradial residual limb. Additionally, the thermal protection characteristics
of silicone have become more popular for thermal protection use, such as hot
pad or even a silicone glove for handling stove pans or baking utensils in
the kitchen and even as a baking pan.
 
I have Google Searched potential information regarding this and have not
found any documentation that might verify my opinion that silicone... or any
gel liner for that matter... might work just as well as the tried and true
neoprene wet suit garments.
 
I suspect our use in prosthetics is the only application where a silicone
garment (residual limb gel liner) is being used over the human body; however,
in our case it is primarily being used as an ideal material for tissue
trauma protection from pressure and shear forces, rather than for thermal
protection.
 
I have absolutely know experience with the use of a wet suit. I am hoping
someone out there in the world of prosthetics has had first hand experience
with the above described situation, either in their practice experience or
possibly as an amputee with cold water diving experience, who possibly has
possibly used a gel liner for this purpose.
 
Thank you in advance for any input!!
 
John N. Billock, CPO/L, FAAOP
Warren, Ohio USA

  
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I'm a cold water diver but haven't used a gel liner on my residual limb
while diving. I had my suit customized so that my amp side sleeve is cut shorter
and sewed shut. It stays pretty warm even in water temps to 42 degrees. That's
 an interesting idea though, let me know how it plays out....
 
  
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Neoprene will not keep you warm in the water without the thin film of water
that leaks into your wet suit and makes a seal. Silicone may be better.
 
  
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Wet suits are just that, wet. It is the layer of water held next to the skin
that forms the insulating barrier not the neoprene. Silicone is just as
prone to absorbing heat as it cold.
 
  
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 The wet suit is actually allowing a thin layer of water inside of the suit.
 Then body heat warms the waterand thereby keeps heat in. The wet suit is
much thinner than a dry suit and does not allow as good protection as the dry
suit. Obviously, the dry suit does not allow water inside. That does not
answer your question, but it does give you a place to start. A thin silicone
probably will act somewhat like a wet suit, but by virtue of the 1.5 to 3 mm
thickness, it probably will not insulate as well as 6mm neoprene, which is
what most wet suits are made of.
 
  
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Glen Klute at the University of Washington has done work on residual limb
temperatures in amputees wearing different liners. He has shown that the
residual limb skin temperature tends to stay high once raised because of normal
activity when wearing silicone based liners. This would indicate that the
silicone liners prevents heat from being dissipated by the limb.
A wet suit works by heating the water trapped between the body and the
neoprene suit.
 
Note: I have contacted Dr. Klut directly for any further input he might
offer. JNB
 
  
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I believe that the neoprene would work better. If not used while wearing a
prosthesis, then one could sew it without an issue. I used neoprene stump
knee pads to wrestle with in high school, and besides the padding protection,
they provided heat.
I believe in O&P, the suspension sleeve example would show the heat
difference. A neoprene sleeve creates more heat and issues than the newer style
silicon type.
 
  
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Neoprene only works by trapping a thin layer of water next to the skin to be
warmed by the body. It isn't that great of a dry insulator because it
doesn't have much loft (think down sleeping bag)... I suspect that silicone would
provide greater resistance to heat transfer than the neoprene. Staying warm
= staying dry and having ample airspace between the skin and outside
environment. A custom glove would probably fare better than a tight, liner-like
device as it can trap more air and thus more warmth. Good luck!
 
  
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I don't know about the silicone/neoprene comparison, but I heard something
interesting yesterday. A client of mine goes pheasant hunting each year in
South Dakota. He has terrible feet and ankles, largely fused, and is a scrub RN.
So, when he hunts, he is primarily a blocker and does limited walking.
Anyway, he told me about these Milar sleeves that he purchases at Cabella's. The
way he described it, they zip over his shoes and legs, like chaps I guess. He
says that his feet stay warm with these applied. Since he doesn't walk much
when hunting, I thought this was significant. You might take a look at this.
 
  
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I used to dive a fair amount. I'm not sure I can answer you question but
can offer some experience on how neoprene works for diving. Basically, a layer
of water enters the wet suit. Your body then warms the water and the
neoprene serves as an insulator and holds the warm water next to your body. I used
to quarry dive in 50 degree water. This is kind of gross, but we would
drink a lot of coffee before diving and pee into our wet suit as soon as we
entered the water. This way, our body did not have to warm the water, it was
already warm. As nasty as this sounds, it is (or was) common practice for cold
water diving with a wet suit---not a dry suit. You probably didn't expect a
response like this, did you.
 
  
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