reply summary- cuts in comfort liners

reply summary- cuts in comfort liners

Joan Cestaro, C.P.

4/20/2001

Dear members,

I have received a considerable number of replies from the list and realize
this is a pretty wide spread problem. It's at least nice to know that I'm
not alone! It sounds as though the problem is lack of total contact and/or
voids in the socket causing shear stresses on the liner. This in turn
causes the gel breakdown. And I certainly admit that I do not follow the
standard protocol that is recommended by the liner manufacturers (most of
them) stating reduction only with no build-ups on the positive mold. I
still relieve for the distal tib and fib head standardly, at the very least.
I do not agree that Practitioners should modify based solely on prolonging
the longevity of the liners. In my most recent case of the gel breakdown,
the lady is a 40+ year old, amputated as a child. She is as a conically
shaped as they come. So, this theory certainly makes sense for this case.
She was cast with the Icecast machine, but there may certainly be distal
voids r/t her shape.

Following is a post from a representative at Ossur who describes the problem
and the possible cure. I hope this helps all of those who responded having
this same problem. Good luck to everyone and thanks to all who responded to
my querry!

Joan Cestaro, C.P.

Ossur reply- from Mark Muller:

The slits are formed from the silicon pulling away from its self where there
is a void. This sometimes occurs in places where the socket has been built
up like distal tibia or fib head etc... What happens is when there is a void
in the socket the silicon migrates to fill that void and pulls away from its
self and separates. These slits should not be a source of breakdown on a
residual limb unless there is excessive pressure in that area.

How I solve this problem is with silicon putty in the area to fill the void.
Place a small piece of silicon putty or what ever putty you want to use with
a piece of cling film over it so it does not stick to your liner. Then have
the pt. stand or walk with the putty in place to pack it out and fill the
void. Remove the putty. Then replace the putty with pelite that you form
in the shape of the removed putty. You can use two part silicon or any
other soft product that doesn't pack out to fill the void instead of
pelite. You want to give our pt. relief but not loose your total contact
or total surface bearing interface. If it is a total contact socket with
evenly distributed pressure it should not occur. I'm not saying that you
don't have a total contact fit but those slits can happen in situations with
a void. It could also happen at the distal aspect of the liner if the
socket is pistoning during swing phase. This can occur if the socket was
not elongated during casting.

The silicon in the Comfort liner is very soft. That makes it very
comfortable but it also makes is susceptible to these stresses . You may
want to switch to a firmer silicon like in the Dermo liner. You can get the
Dermo silicon, with aloe, in the same profile as the Comfort liner. So you
can retro fit them.

Hope all is well, I'll speak to you soon.