gel liners and preparatory prostheses
Ed Neumann
Description
Collection
Title:
gel liners and preparatory prostheses
Creator:
Ed Neumann
Date:
10/10/2003
Text:
Thanks to all who responded. My question concerned preference for and
experience with the use of gel liners versus traditional PTB/Pelite systems
for preparatory prostheses. I did not receive as many responses as I had
hoped for, but I also have held discussions with prosthetists I know and
have incorporated some of their thoughts in the following.
It would appear that the gel liners are easier to fit, and in the hands of
the less-experienced prosthetist, have fewer fitting problems. Meanwhile,
prosthetists who had to cut their teeth on the older techniques of Pelite
and socks, and were able to master them, have a great deal of confidence in
the older methods. One could hypothesize that the attractiveness of the
older methods to prosthetists who prefer traditional methods may lie partly
in the investment of effort required to gain the skills necessary to use
them successfully, combined with the challenge they present.
Often, one of the main concerns I have heard expressed with use of gel
liners for preparatory prostheses is that the cost incurred when the
patient quickly shrinks out of the liner, and the fact that by the time the
patient is into 12 or 15 ply of socks (a point to which both traditional
PTB and gel liner techniques appear to converge with preparatory
prostheses), and at least one change of gel liner thickness to accommodate
volume changes, the possible benefits derived from the gel liner fall short
of the extra costs charged to insurers (if insurers will pay for gel liners
at all). However, some responders rebut this argument.
A key issue should be whether the older or newer methods are better for the
patient. A selling point for learning the older methods well is that they
could possibly make one a better fitter, because they force one to think
about the dynamic interplay of tissue thickness and pressure created by
hard socket walls during gait, and the likely problem locations inside a
socket. This benefits the patient, and probably many of the prosthetists
who mastered the older methods but switched to the gel liners continue to
modify casts in some semblance of the PTB style. As far as the benefits of
gel to the patient, there is plenty of anecdotal evidence that they help
simplify and avoid fit problems (particularly in the hands of the less
experienced prosthetist), but relatively few research studies. The paper
cited below by Christoper Lake and Terry Supan (JPO, Vol 9, No. 3, Summer,
1997, pp. 97-106) provides a rationale for using gel liners for preparatory
prostheses, and makes a number of good points in their favor. However,
another research study by Kim Coleman, (ICAP2 and abstracts T06-2 and W05-5
at the Glasgow ISPO) based one type of gel liner and controls suggests that
gel liners may become less comfortable during the course of the day, and
patients may actually prefer to do less walking as a result. The fact that
articles are still appearing on how to cast and fit gel liners (Tech Tips
by Paul Singh, O&P Business News, Sept. 15, 2003, p. 58) suggests that
achieving a good fit with them may not be as intuitive as one would think
(e.g. just envelop the limb in a thick layer of prosthetic fat to absorb
impact and shear).
A follow-up question concerning modifications was sent to those who
responded, and their answers are presented following the initial responses.
Individual prosthetists appear to develop their own principles of cast
modification to accommodate the fitting problem peculiarities of each brand
of liner. A worthwhile research project might be to examine what these
modifications consist of for the commonly used brands of liners, to
determine where commonalities exist, where divergences occur, and what
problem the prosthetist is trying to solve or avoid by making the
modification (i.e. what fitting goal is sought).
In the context of preparatory prostheses, which was the focus of the
initial question, a good research question might be how best to adjust the
socket/gel liner system as limb volume shrinks so that a good fit can be
maintained. Volume loss is not uniform, but proportional to tissue type
and thickness. Adding socks pushes the limb up out of the socket, so fit
can change for the worse where bone lies close to the skin (e.g. around the
tibial plateau, patella tendon, condyles, etc.). Decreasing socket volume
via pads changes the geometry of the socket, can be difficult to do
correctly (it is an art form), and may hasten liner deterioration.
Reforming the socket by heating it and changing the geometry also requires
skill, and frequently is accompanied by some unwanted changes in socket
geometry since it is difficult to control the amount of strain generated in
regions adjacent to the primary site of modification. A simple (i.e. does
not utilize water, reservoirs, and valves), low-cost, gel-age technology
for accommodating volume changes in preparatory prostheses which would be
superior to socks, pads, or heating could benefit prosthetics.
Responses begin below.
INITIAL RESPONSES
______________________________
I use silicone liners whenever funding is available for them, regardless of
how long after the amputation the fitting is taking place (assuming wound
closure and healing has taken place.) In my experience, the adjustment
process is no more complicated by the use of a silicone liner. High risk
patients (diabetics, particularly) are much safer in a silicone liner. The
only eligible patients I don't use a silicone liner on are those who are
unable to don the liner, have significant RL issue (skin problems, unusual
shape), are non-compliant, or those who reject it for whatever reason. This
all applies to both AKs and BKs.
________________________________
The survey that Chris Lake did as a resident at SIU found that patients had
significantly more problems when they transitioned from non gel to gel
prostheses. Although it is several years old and the liners have changed
you may want to reread his article published in the JPO. Based on that
research our practice changed to use gel liners in the first prosthesis. If
you fit the limb on the snug side initially, changing to a smaller size is
the exception. At most they go down only one size and usually when they are
ready for the permanent prosthesis when they need a new liner anyway.
________________________________
My solution is to rarely fit preparatory prostheses. Fifteen years of using
3S suspension variations has produced results, though rarely quantified,
that overwhelmingly preclude the use of traditional designs in most cases.
I fit initial definitive prostheses and replace the socket at the
appropriate time(s). There is something to be said for quality and the
added advantage of starting the patient's gait training with the foot they
will end up using. Also, most of the suspension components of recent years
have been developed for the diabetic and disvascular populations. Of
course, there are always exceptions.
_________________________________
I am one of those who would not willingly go back to the old conventionals.
In fact, I have written an article to this effect in OP World last year. I
believe the interim (preparatory) is dead. All of my patients have been
vascular/diabetic, and 85% have been geriatric.
__________________________________
[I have used] many liners on temporaries. Best luck with
Alpha's. Pin/locking not reimbursable with Medicare here. Much success
with cushion gel liners and sleeves-especially with diabetics. Gel softens
the scar and protects the distal tibia as shrinkage
occurs. Pain is significantly decreased; enables them to perform higher
levels of activity faster without assistive devices. No dressings except I
cut a Jim Smith 1-ply sock and cover the distal 1/3 for drainage. It acts
as a prevention for maceration. Liner keeps it in place nicely. I will
place locking liners on Medicare temporaries if there is an inability to
adequately pull the sleeve all the way up. I start with 3mm if they are
large and bulbous. As shrinkage occurs, instead of replacing the socket, I
can go to 6mm for considerably less money than a socket replacement. If it
is a smaller patient, have had success with starting with 6mm. Shrinkage
occurs(12-15 ply) I use the same 6mm for the permanent. Significant
re-shaping of the liner is possible by heating and molding to the patient's
smaller cast model. I use CAD-CAM so I can reduce the old model with recent
measurements. Locking liners are SO MUCH more preferred than the sleeves,
I give them a choice for their permanent. Must be aware of the
disadvantages of long-term locking liner use on some patients. Watch for
fibular head migration around the 4-5 year mark. Successes did not occur
until we experimented with every lock on the planet it seems. Chose the
Bulldog/PDI style and eliminated negative pressure issues in swing phase
and NOISE. My AK's strictly have only had success with OSSUR liners due to
elongation problems. Reinforced matrix is superior-using same locks for
them. Majority
of our patient population is diabetic/vascular related fittings.
_______________________________________
To answer your question, I use the silicone liners and pin systems on the
new bk amputees here. I was forced to do the old style of prosthetics by a
previous employer, and they were disasters. Even after having the patient
in that kind of leg for 12 months, and then switching them to the liner
system, they would then shrink again. Then you had to do another socket
change for the volume loss, again. It was very inconvenient for the patient
and really frustrating for them. So I am back to the method of making the
kind of leg that they are going to use from the beginning. They usually get
about 6 months or so with the liner/socket on the first leg. Then after the
6 or 8 months when they are into 15 ply or more (depending on the patient
of course) then I will make them another leg and get the smaller liner, new
socket, etc.
The old method is like giving a tricycle to someone for drivers education,
and then all of the sudden jumping them into a big cadillac 6 months after
they have used the tricycle. Why not give them a nice comfortable leg from
the beginning.
I really don't ever plan on making an old pelite kind of leg here at my
office. They are not comfortable and the hygiene with them is horrible.
_____________________________
We start our new amputees out with a Pelite liner and sleeve suspension.
Once the stump is more mature we may move to a pin system. Have found
problems when going to a pin system on a new amputee. We have been going to
pin suspension for AKs when well healed.
MODIFICATION FOLLOW-UP QUESTION
I use the Icecast casting system (vacuum pressure) and use primarily Ossur
liners. I have found that the Alpha liners from OWW do not last as long,
and I am much more limited in socket design. The Alpha liner must be fit
in a socket with little to no buildup on boney prominences. The Ossur
liners allow some buildup to be used. I like having that option. So the
basic design is Total Surface Bearing, but I use a patellar bar, posterior
brim, anterior distal tibial buildup, and a fibular head buildup if necessary.
I use the Northwestern (NURIC) socket design for AKs, and am getting more
aggressive with the modification below the ischium and along the
lateral/posterior wall (like the Hanger Comfort Flex socket.) When using
the gel liner I use essentially the same modifications, and just
accommodate the added circumference within the socket.
________________________________
For BKs and AKs I generally let the liners produce the tension variables
(so I make the mold over the liner.) For BKs I use modification techniques
for total surface bearing except when using TEC urethane liners. With Tec
systems more weight can be tolerated
distally. For AKs I use an ischial containment brim modification and trim
the liner uniformly at the ischial level. Interestingly, even when
replacing the sockets due to volume reduction, in many cases the same size
liner can still be used- so new liners do not always have to be provided
with socket changes.
_________________________________
For TTs, I usually do an Icecast type impression with a 4% reduction in non
bony areas. If the distal end is greater that the tibial tubrical level I
modify the amount of reduction. Unfortunately that one is based on
experience and not any set rule.
Edward S. Neumann, PhD, PE, CP
Professor of Civil and Environmental Engineering
Box 454015
University of Nevada, Las Vegas
Las Vegas, NV 89154-4015
PH: 702 895 1072
FAX 702 895 3936
experience with the use of gel liners versus traditional PTB/Pelite systems
for preparatory prostheses. I did not receive as many responses as I had
hoped for, but I also have held discussions with prosthetists I know and
have incorporated some of their thoughts in the following.
It would appear that the gel liners are easier to fit, and in the hands of
the less-experienced prosthetist, have fewer fitting problems. Meanwhile,
prosthetists who had to cut their teeth on the older techniques of Pelite
and socks, and were able to master them, have a great deal of confidence in
the older methods. One could hypothesize that the attractiveness of the
older methods to prosthetists who prefer traditional methods may lie partly
in the investment of effort required to gain the skills necessary to use
them successfully, combined with the challenge they present.
Often, one of the main concerns I have heard expressed with use of gel
liners for preparatory prostheses is that the cost incurred when the
patient quickly shrinks out of the liner, and the fact that by the time the
patient is into 12 or 15 ply of socks (a point to which both traditional
PTB and gel liner techniques appear to converge with preparatory
prostheses), and at least one change of gel liner thickness to accommodate
volume changes, the possible benefits derived from the gel liner fall short
of the extra costs charged to insurers (if insurers will pay for gel liners
at all). However, some responders rebut this argument.
A key issue should be whether the older or newer methods are better for the
patient. A selling point for learning the older methods well is that they
could possibly make one a better fitter, because they force one to think
about the dynamic interplay of tissue thickness and pressure created by
hard socket walls during gait, and the likely problem locations inside a
socket. This benefits the patient, and probably many of the prosthetists
who mastered the older methods but switched to the gel liners continue to
modify casts in some semblance of the PTB style. As far as the benefits of
gel to the patient, there is plenty of anecdotal evidence that they help
simplify and avoid fit problems (particularly in the hands of the less
experienced prosthetist), but relatively few research studies. The paper
cited below by Christoper Lake and Terry Supan (JPO, Vol 9, No. 3, Summer,
1997, pp. 97-106) provides a rationale for using gel liners for preparatory
prostheses, and makes a number of good points in their favor. However,
another research study by Kim Coleman, (ICAP2 and abstracts T06-2 and W05-5
at the Glasgow ISPO) based one type of gel liner and controls suggests that
gel liners may become less comfortable during the course of the day, and
patients may actually prefer to do less walking as a result. The fact that
articles are still appearing on how to cast and fit gel liners (Tech Tips
by Paul Singh, O&P Business News, Sept. 15, 2003, p. 58) suggests that
achieving a good fit with them may not be as intuitive as one would think
(e.g. just envelop the limb in a thick layer of prosthetic fat to absorb
impact and shear).
A follow-up question concerning modifications was sent to those who
responded, and their answers are presented following the initial responses.
Individual prosthetists appear to develop their own principles of cast
modification to accommodate the fitting problem peculiarities of each brand
of liner. A worthwhile research project might be to examine what these
modifications consist of for the commonly used brands of liners, to
determine where commonalities exist, where divergences occur, and what
problem the prosthetist is trying to solve or avoid by making the
modification (i.e. what fitting goal is sought).
In the context of preparatory prostheses, which was the focus of the
initial question, a good research question might be how best to adjust the
socket/gel liner system as limb volume shrinks so that a good fit can be
maintained. Volume loss is not uniform, but proportional to tissue type
and thickness. Adding socks pushes the limb up out of the socket, so fit
can change for the worse where bone lies close to the skin (e.g. around the
tibial plateau, patella tendon, condyles, etc.). Decreasing socket volume
via pads changes the geometry of the socket, can be difficult to do
correctly (it is an art form), and may hasten liner deterioration.
Reforming the socket by heating it and changing the geometry also requires
skill, and frequently is accompanied by some unwanted changes in socket
geometry since it is difficult to control the amount of strain generated in
regions adjacent to the primary site of modification. A simple (i.e. does
not utilize water, reservoirs, and valves), low-cost, gel-age technology
for accommodating volume changes in preparatory prostheses which would be
superior to socks, pads, or heating could benefit prosthetics.
Responses begin below.
INITIAL RESPONSES
______________________________
I use silicone liners whenever funding is available for them, regardless of
how long after the amputation the fitting is taking place (assuming wound
closure and healing has taken place.) In my experience, the adjustment
process is no more complicated by the use of a silicone liner. High risk
patients (diabetics, particularly) are much safer in a silicone liner. The
only eligible patients I don't use a silicone liner on are those who are
unable to don the liner, have significant RL issue (skin problems, unusual
shape), are non-compliant, or those who reject it for whatever reason. This
all applies to both AKs and BKs.
________________________________
The survey that Chris Lake did as a resident at SIU found that patients had
significantly more problems when they transitioned from non gel to gel
prostheses. Although it is several years old and the liners have changed
you may want to reread his article published in the JPO. Based on that
research our practice changed to use gel liners in the first prosthesis. If
you fit the limb on the snug side initially, changing to a smaller size is
the exception. At most they go down only one size and usually when they are
ready for the permanent prosthesis when they need a new liner anyway.
________________________________
My solution is to rarely fit preparatory prostheses. Fifteen years of using
3S suspension variations has produced results, though rarely quantified,
that overwhelmingly preclude the use of traditional designs in most cases.
I fit initial definitive prostheses and replace the socket at the
appropriate time(s). There is something to be said for quality and the
added advantage of starting the patient's gait training with the foot they
will end up using. Also, most of the suspension components of recent years
have been developed for the diabetic and disvascular populations. Of
course, there are always exceptions.
_________________________________
I am one of those who would not willingly go back to the old conventionals.
In fact, I have written an article to this effect in OP World last year. I
believe the interim (preparatory) is dead. All of my patients have been
vascular/diabetic, and 85% have been geriatric.
__________________________________
[I have used] many liners on temporaries. Best luck with
Alpha's. Pin/locking not reimbursable with Medicare here. Much success
with cushion gel liners and sleeves-especially with diabetics. Gel softens
the scar and protects the distal tibia as shrinkage
occurs. Pain is significantly decreased; enables them to perform higher
levels of activity faster without assistive devices. No dressings except I
cut a Jim Smith 1-ply sock and cover the distal 1/3 for drainage. It acts
as a prevention for maceration. Liner keeps it in place nicely. I will
place locking liners on Medicare temporaries if there is an inability to
adequately pull the sleeve all the way up. I start with 3mm if they are
large and bulbous. As shrinkage occurs, instead of replacing the socket, I
can go to 6mm for considerably less money than a socket replacement. If it
is a smaller patient, have had success with starting with 6mm. Shrinkage
occurs(12-15 ply) I use the same 6mm for the permanent. Significant
re-shaping of the liner is possible by heating and molding to the patient's
smaller cast model. I use CAD-CAM so I can reduce the old model with recent
measurements. Locking liners are SO MUCH more preferred than the sleeves,
I give them a choice for their permanent. Must be aware of the
disadvantages of long-term locking liner use on some patients. Watch for
fibular head migration around the 4-5 year mark. Successes did not occur
until we experimented with every lock on the planet it seems. Chose the
Bulldog/PDI style and eliminated negative pressure issues in swing phase
and NOISE. My AK's strictly have only had success with OSSUR liners due to
elongation problems. Reinforced matrix is superior-using same locks for
them. Majority
of our patient population is diabetic/vascular related fittings.
_______________________________________
To answer your question, I use the silicone liners and pin systems on the
new bk amputees here. I was forced to do the old style of prosthetics by a
previous employer, and they were disasters. Even after having the patient
in that kind of leg for 12 months, and then switching them to the liner
system, they would then shrink again. Then you had to do another socket
change for the volume loss, again. It was very inconvenient for the patient
and really frustrating for them. So I am back to the method of making the
kind of leg that they are going to use from the beginning. They usually get
about 6 months or so with the liner/socket on the first leg. Then after the
6 or 8 months when they are into 15 ply or more (depending on the patient
of course) then I will make them another leg and get the smaller liner, new
socket, etc.
The old method is like giving a tricycle to someone for drivers education,
and then all of the sudden jumping them into a big cadillac 6 months after
they have used the tricycle. Why not give them a nice comfortable leg from
the beginning.
I really don't ever plan on making an old pelite kind of leg here at my
office. They are not comfortable and the hygiene with them is horrible.
_____________________________
We start our new amputees out with a Pelite liner and sleeve suspension.
Once the stump is more mature we may move to a pin system. Have found
problems when going to a pin system on a new amputee. We have been going to
pin suspension for AKs when well healed.
MODIFICATION FOLLOW-UP QUESTION
I use the Icecast casting system (vacuum pressure) and use primarily Ossur
liners. I have found that the Alpha liners from OWW do not last as long,
and I am much more limited in socket design. The Alpha liner must be fit
in a socket with little to no buildup on boney prominences. The Ossur
liners allow some buildup to be used. I like having that option. So the
basic design is Total Surface Bearing, but I use a patellar bar, posterior
brim, anterior distal tibial buildup, and a fibular head buildup if necessary.
I use the Northwestern (NURIC) socket design for AKs, and am getting more
aggressive with the modification below the ischium and along the
lateral/posterior wall (like the Hanger Comfort Flex socket.) When using
the gel liner I use essentially the same modifications, and just
accommodate the added circumference within the socket.
________________________________
For BKs and AKs I generally let the liners produce the tension variables
(so I make the mold over the liner.) For BKs I use modification techniques
for total surface bearing except when using TEC urethane liners. With Tec
systems more weight can be tolerated
distally. For AKs I use an ischial containment brim modification and trim
the liner uniformly at the ischial level. Interestingly, even when
replacing the sockets due to volume reduction, in many cases the same size
liner can still be used- so new liners do not always have to be provided
with socket changes.
_________________________________
For TTs, I usually do an Icecast type impression with a 4% reduction in non
bony areas. If the distal end is greater that the tibial tubrical level I
modify the amount of reduction. Unfortunately that one is based on
experience and not any set rule.
Edward S. Neumann, PhD, PE, CP
Professor of Civil and Environmental Engineering
Box 454015
University of Nevada, Las Vegas
Las Vegas, NV 89154-4015
PH: 702 895 1072
FAX 702 895 3936
Citation
Ed Neumann, “gel liners and preparatory prostheses,” Digital Resource Foundation for Orthotics and Prosthetics, accessed November 24, 2024, https://library.drfop.org/items/show/221904.
