[AMP-L] Vacuum Assisted Suspension Systems

[Wayne Renardson]

>From OANDP-L wilth permission of Mr. Ted Trower, CPO


The original question was:

I'd like to ask that anyone with experience with more than one of the
vacuum assisted suspension systems share their impressions of the 
advantages and disadvantages of the various systems.  I'd be 
especially interested in your impressions regarding the durability of
the units.


Responses follow:
========================================

I'm anxious to see your results.  We have had good results with the 
Harmony system, bad results with the Otto bock E pulse and good 
results with Limb-Logic.  
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I have only used the suspension sleeves from Alps with the built in 
expulsion valves.  Works well, some patient find very easy, simple, 
good alternative to even pin system.  

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I've used the Harmony red units, the HD, the Otto Bock e-Pulse, and 
the Jim Smith Evac.

Jim Smith's system, from my experience has been the least reliable 
and least durable. Problems often seemed to arise for no reason 
reflecting on the manufacturer's quality control which hasn't been 
very impressive.

The Harmony pump systems have come a long way from that of the red 
units first designed by TEC. The new HD and P2 appear to be favorably
more durable requiring fewer repairs to both the valve and suction 
assemblies as well as to the shock system now that it has been 
replaced with the urethane rod design over the air shock. My only 
complaint is the new urethane shock system isn't as adjustable in 
relation to vacuum draw as the air shock was. Some of my patients 
have complained that it draws too much vacuum even when set with the
least amount of travel.

The e-Pulse however has been a great system to work with. The four 
vacuum adjustments are easy to navigate and the design itself is very
intuitive incorporating an on-board diagnostic alert system. Otto 
Bock has done a pretty good job with the unit however there are some
minute issues with the system. The pre-filters tend to leak after 
awhile unless they're very well protected. In a temporary prosthesis
it is something to consider if you're having problem maintaining 
vacuum. The e-Pulse is relatively quiet which I can't really say for
the Evac. I feel that the next generation of e-Pulse will be welcomed
although for the time being the first design works great. The only 
other drawback is the lack of shock absorption designed into the 
system. Adding a modular shock is easy enough but for a longer BKA 
I've found that using a good shock absorbing foot makes the entire 
system that much nicer. I've used the Renegade with the e-Pulse and 
have had great results. Lastly, as far as finishing both the Evac and
e-Pulse present some challenges in comparison to the Harmony inline 
systems but it can be done.
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I have fit several of the E-Vac units and have heard the same thing 
from all of the patients. They love it when it is working. There have 
been some durability problems with the E-Vac systems except that Jim 
Smith Global is more than willing to repair or replace the units when 
they go bad.  

I am impressed with the Limb Logic from OWW. It seems like it is more 
durable. The downfall of both systems is finding a sleeve that is 
more puncture proof. I have worn both and the suspension is 
unbeatable when It's working.  
-----------

Epulse: advantage- adds no build height, user adjustable. 
Disadvantage- hard to mount or carry in pocket.  Filter leaks
occasionally.

Limb logic: advantage- solid piece (no tubes).  Disadvantage- adds 
build height.  Leaks if socket not fabricated correctly.

----------
I assume you are referring to powered vacuum assisted systems.

We have found the OWW unit to work quite well although they need to 
make improvements to the port options, allowing additional attachment 
configurations, which I understand is being resolved. It has proven 
to work very well in two very difficult fitting cases to maintain a 
very stable socket environment and has withstood heavy body weight in 
one case. The four hole attachment screws will bind if you are not 
very careful during fabrication.  

The Otto Bock unit is a piece of !@%#!$#@ and from my understanding 
is not being sold while it is redesigned....  

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I have used the smith global EVAC, the Otto Bock Epulse and the OWW 
Limblogic.  First I will say that the patients I have on them for the 
most part really love them and will gladly put up with some of the 
inconviences associated with them.  I used the EVAC for several 
months with very good success.  They are pretty easy to maintain and 
Smith Global will send out a loaner when there are problems.  I had 
very little success with the e-pulse by Otto Bock.  They seemed to 
malfunction more then EVAC.  The limblogic is the pump I am using the 
most now.  It is very nice in that it is integrated into the system, 
and you don't have to Velcro it to the side of the pylon.  

I will say however I was having trouble with it leaking until I 
actually followed their instructions to the T.  Once I did that it 
has worked very well.  The only downside to it is I have had a couple 
of patients that bent some of the prongs on the charger so I am 
getting a new charger for them.  

Also the exhaust tube port is useless because I can not get it to 
stay plugged in, but that is no big deal in my opinion and the 
benefits far outweigh any on the negatives.  Hope this helps I will 
gladly answer any questions you may have.  

----------------

I have used the Harmony quite a bit but find it finicky.  Patient 
selection is a very important part of this system.  I have delivered 
six over the past few years and two of the units had to have over 
$300 in repairs.  When the system is working it is great.  

I recently used a Limb Logic pump.  This is much easier to use but 
had to send it back within four weeks for repair.  I do not think it 
offers as good of suspension as the Harmony.  It is, however much 
easier to use and fabricate.  

=====
As always many thanks to all who took the time to reply and share 
their experience.


Ted A. Trower C.P.O., FAAOP
A-S-C Orthotics & Prosthetics
Jackson, Michigan, USA

<www.amputee.com>