One attendee reported several interesting sound bytes or bites from the seminar. He recalled that Andy from OWW said they have had good results from Alpha Liners when used with the Limb Logic on transtibial residual limbs;  as for tranfemoral, he said they don't encourage using elevated vacuum for transfemoral. He also said the more vacuum the better unless there are unusual skin issues. He likes a minimum of 14 mm Hg for good results.

Since it is my blog, I get to be the first reponder.  As for transfemoral, if people are happy with thier less complicated sytems, I agree that there is no need to change to EV, but it is sure nice to have that tool when you need more stability, better suspension, less volumetic instability, and more hip range of motion.  

Mechanical hand vacuum pumps can be used to elevate the vacuum for testing purposes in the prosthetist's office as well as by patients for applying thier prosthesis (if the socket  was designed with that in mind).

We have tried a number of pumps and by far the best is the Craftsman all metal brake bleeding pump from Sears. It is much more durable than the plastic version. Inexpensive. and easy to find at Sears. It has a good guage, and it pumps up higher than any of the other pumps. And Craftsman has a good warrantee to boot.

It is the heaviest of the hand pumps so it  may not be appropriate for patients to carry around. But if a lighter pump is preferred, I would still recommend also having the all metal pump for use in the office or at home. It is so much better.

Elevated vacuum sockets use gel liners as a skin interface. One of the first decisions required when fitting elevated vacuum is which liner?   I have my answer and, as always, I invite others to share their experiences and opinions.  

There are two saying that I keep in mind when looking for leaks in an elevated vacuum prosthesis.

2010 hold lots of promise in elevated vacuum prosthetics. But let's see... where does elevated vacuum need to go?

We lack the three C's.  We lack consensus, we lack consistency, we lack communication. 

For elevated vacuum to become an accepted technique by the schools, by ABC, and by payors, it needs all of these things. Many people are applying the term, "elevated vacuum" to a variety of different techniques and by the same token many people are applying different terminology to the same technique (elevated vacuum, sub-atmospheric suspension, sub-ischial design, negative pressure, etc) .  It reminds me of the confusion between CATCAM, ischial containment, Long's Line, and narrow ML socket design. (I defy anyone to collect 100 random non-quadrilateral transfemoral sockets from the around the US and match the socket design to the name consistantly)

But the good news is that we have the three I's. Innovation, independence, and imagination.  The seemingly fragmented and independent development is the very thing that resulted in much more innovation and novelty in the evolution of these systems. Rushing toward a single solution would have resulted in a much less interesting beast in both the CATCAM and the Elevated Vacuum examples.

With a new year at hand, we continue the hard work of establishing elevating vacuum into a mature and accepted prosthetic approach, while enjoying the fun of coming up with new ideas at every turn. 

Yet another moving target!  HAPPY NEW YEAR,

I just recieved another call asking me to clarify the recommended height of trimlines on an elevated vacuum transfemoral socket. In the phone call the prosthetist said he asked a number of prosthetists and the responses were "all over the map".

I would like to first argue that it is incorrect to use the term "sub-ischial sockets" when referring to elevated vacuum transfemoral prostheses. One main difference between elevated vacuum and most other designs is that other designs such as the quad socket have specifically designed trimlines. In the case of elevated vacuum, the height is just as critical, but it depends on the individual patient and residual limb characterists. In one case the proper height is ischial level and in another it is 1" below the ischium.Keep in mind that trimlines affect stability, support, and suspension, but also affect comfort and range of motion. Too low, and the socket will not work; too high and there is unecssary restriction and discomfort.

There is no scientific way to determine the exact location, but in my experience there is no reason to go proximal to the ischium even on the short limbs.On short limbs the proximal brim helps to maintain a good seal between the inner gel liner and the sealing sleeve which is taped to the inner vacuum cap. 

On long residual limbs, I begin at ischial level and  then check for hip joint range of motion. If there is any restriction of range of motion even in the extreme limits, I lower the trimlines. Once the socket is comfortable with full range of motion, I do not lower the trimlines any further. I then fabricate the final socket with a flexible proximal brim.

I welcome other input from "the map".

My first absolute rejection of elevated vacuum was a recent Syme patient. I know that others have worked out well, but this man could not get past the application, fitting and removal of the liner.

He is a large 70 year old gentleman with vascular insufficiency.  In designing his prosthesis,  I had to consider that, when sitting, he is not able to bend sufficiently to touch his shoe or lower half of his Syme prosthesis (therefore a window with a sleeve ovet it was out of the question). Currently he uses a system with a window which slips into a ledge distally and fastens with a strap proximally. For elevated vacuum I decided to try a custom gel liner  which is built up proximal to the malleoli so that he can slip it into a solid outer socket and seal it with a proximal sleeve. Alas, he was unable to don the liner in the normal way, by reflecting it back on itself, due to his limited range of motion. He could apply it with lotion and it was very comfortable. But then he could not remove the liner independently.  After several liner designs and several socket designs, we are abandoning elevated vacuum for him. This does not mean that I would not fit elevated vacuum to the next Syme patient I see, but it means that it is not for everyone.

New products are potential new options for patients and the hand-held vacuum pump from Evolution Liners is one of those products. It fills a critical void for those elevated vacuum patients who use the vacuum-chamber-and-hand-pump system but lack the hand strength or dexterity to pump the socket vacuum to the necessary level. (the higher the vacuum the better, but 13" to 15" Hg is the minimum acceptable) We have tried Vacuum Seal pumps and other cheap pumps available at the mall, and found that they can't deliver. The Evolution Pump pumps up to 23" Hg, uses two AA batteries, and is smaller and lighter than my I-Phone (which, to date has no app for pumping up an elevated vacuum socket) 

I have found that some patients develop skin irritaion in the liner in an elevated vacuum socket if no lubrication is used.  Others prefer no lubrication and have had no problmes for years. Some prefer lubricating only in certian areas for example over an adhered scars or near the proximal brim. A man with a Syme's.  I recently fit with a new custom silicon liner could only tolerate the liner when it was lubricated inside. When it was applied dry, he was exteremely uncomfortable as soon as the liner was applied.