I am working with a transtibial patient who has a well fitting check socket and uses a hand pump and likes it. I am installing an Airpuck. If you follow the instructions, you end up with a void betweent the distal residual limb and the Airpuck, which they suggest you fill by squirting silicon into it. An alternative I am trying is to fill the well-fitting check socket with plaster. then fabricate a Pelite end pad over the positive model. Then create a flat surface on the distal end pad to accept the Airpuck dummy. Then fabricate the definitive socket over the dummy with the end pad in place. This preserves the fit of the test socket and transfers it to the dinfinitive socket with the Airpuck installed. Any thoughts on this alternative?

Another component option for sub-atmospheric systems is the Symmetry System from Symmetry Prosthetics. I spoke to Ryan Colby, Director of Operations, to find out what it does, how it works, and what is different about it from other systems.  Here's the scoop: The system, launched in February of 2010, is a socket, a liner, and a pump.  The unique and proprietary components are the pump and the liner. There are two pump options. a passive pump and an electric rechargable active pump.  The electric pump charge lasts about a week and has a maximum vacuum level of 18 mmHg. The liner is composed of a 6mm thick silicon liner with a 3mm skirt that acts as a seal.  A sock can be used as a wick and tucks under the seal, allowing some adjustability by varying sock thickness. No external sleeve is needed and no portion of the liner is rolled over the brim of the socket.  This increases the durability and eliminates the issue of tears casued by the brim of the socket on an external sleeve. Ryan pointed out that the Symmetry liner, unlike other liners with sealing rings, has an adjustable height of the sealing ring. You can put the sealing ring near the top, rather than near the disal end, of the residual limb. He said the tranfemoral system works best with sub-ischial socket designs. For more information, or You Tube links, contact Ryan Colbey at Symmetry Prosthetics.

I received a number of comments on my last posting. The gist of them was that categorizing and naming prosthetic developments is not about reimbursement or coding, and should not be done with that as the motivating factor. Rather, it should be done for the purpose of scientific accuracy or clinical application.  I wholeheartedly agree. It is tantamount to "the tail wagging the dog". 

But the reality is that if the clinicians or researchers don't come up with an accurate and practical nomenclature, the bean counters will do it. They have a different agenda and a loud voice. 

The challenge, of course, is that, in an emerging technology, things are developing so fast that one can't rush into incorporating names. They can quickly be replaced in the next moment. So we come up with working names and that works. Well I leave it for all of us to discuss and comment on.

What's in a word? Suspension, Elevated Vacuum? Suction Socket? Subatmospheric Suspension? Active Suction? Pump?

All of these are just words, but if they are confusing, they can also be misleading. The issue that was brought to my attention is that they mislead case managers who are struggling to wrap thier heads around all of this newfangled stuff.

In truth there is a continuum in socket designs from a socket with socks as the interface, to suction socket, to elevated vacuum socket with a fixed amount of vacuum (hand pump), to an elevated vacuum socket in which the pump regularly adjusts and restores the vacuum (e.g. Harmony, Limb Logic, Edison).

Also we know that elevated vacuum is more than just a suspension method. It stabilizes residual limb volume, reduces perspiration, and adds improved linkage, reducing movement and control. It was suggested to me that we abandon the term "elevated vacuum suspension" as misleading and instead use the words, "elevated vacuum limb volume magangment system"

The other suggestion is to call a system with a hand pump "passive elevated vacuum" and a system with a more dynamic pump "active elevated vacuum".

The thought is that we now have many different suction socket variations, each with different features and benefits, different precription criteria, different cost and complexities and they, perhaps, warrant different reimbursements. One concern is that lumping different technologies, each with a different cost basis, under the same name will encourage insurers to simply set reimbursements at the the level of the cheapest system. And then there goes the proper payment for the more costly active pumps.  How about we look at the words we are using a little more carefully so we don't shoot ourselves in the foot?

Many transfemoral amputees use subatmospheric suspension using a hand pump rather than an automatic pumping system such as the Harmony or electirc pump. Stan Patterson recommends a distal air chamber as a vacuum accumulator when using a hand pump. The Smart Pump is a component designed by Clint Accinni, which is a modular distal air chamber. According to Clint it is super easy to install and eliminates the difficult and time consuming fabrication of an air chamber. Once the prosthesis is complete with the Airpuck, it can be easily converted to a "Smartpuck" electronic pumping system if necessary or desired. The Smartpuck has the same dimensions and uses the same fabrication dummy and attachemnt system as the Airpuck. Build height for either component is 1 3/4 inches. By the way, Clint says the Samrtpuck does alot more than just pump air. It collects lots of data which can be used for assessment and outcomes. All of the Smartpuck functions are controlled through a mobile phone app. For more information Contact Clint Accinni.

I spoke to David Boone for half an hour about the Edison Vacuum System.  He explained the ins and outs of it and there ae plenty!  For a start, this pump has "adaptive control".  That means the transtibial amputee is intimately linked to the prosthesis with high vacuum when walking.  But when he wants to sit, the vacuum eases up. Same thing when he wants to just stand still and chill.  Then if he starts moving around, the vacuum goes back up for better suspension and control.  Add to that the ability for the prosthetist to fine tune the level of vacuum for each activiity. There is also enough on-board memory to store the whole previous week of data.  The system is super quiet and has a battery that lasts several days in between charges. I found it interesting when David commented that he foresees that transfemoral and upper limb amputees might be able to use the Edison puimp with no gel liner; just with socks orf maybe even directly against the skin.  He said this could be possible because the level of vacuum can be lowered to avoid hickies. David emphasized that the many features of the Edison are not added just to load up the system with extras but, rather, that they are there to"meet the unmet needs of the amputees". 

The above review and comments are based on my interview with the manufacturer and do not represent my endorsement or recommendation of the product.  I encourage comments to this blogpost by users with experience with the product.  If you have a component, material or technique related to elevated vacuum and would be like to be interviewed for a review, please let me know by e-mailing me through this blog.

I just realized that since last October, when my e-mail address changed,  I have not been recieving your e-mails you sent me via the blog. Therefore you never got my responses.  We are geting it fixed. Thanks for your patience. Stay with me.

People often ask me about various new components and materials available for subatmospheric socket technology (elevated vacuum). I have been looking at different options for reviewing and reporting on these components as they become available. I considered a version of Consumer Reports in which products are tested by peers and then the results are reported but at this time the logisitcs in doing this accurately and fairly are too difficult.

The process I have chosen is to focus on a conponent for each blog entry and interview the person behind the product, regarding the product's function, features, application, and precription critieria.I will then summarize the interfview and report on it.

Anyone who has a product related to subatmospheric socket technology (elevated vacuum) and wishes to be interviewed can contact me. 

Let me know your thoughts on this idea. And, look for component information in future blog entries.

 The patent pending ColorTouch socket technology finally gives the prosthetist a socket that indicates precisely where high pressure areas are in the socket. The pressure indication is dynamic and indicates the pressure as it is applied. When the clear test socket is adjusted and the pressure is relieved, the socket can be rechecked to assure that pressure has been relieved. This is a great tool and technique for fitting the many patients who cannot report exactly where the pain is coming from. Also for those cases where it is difficult to know where to relieve the socket. I will post images soon. ColorTouch is in beta testing and has not been released yet.

The current issues of Academy Today was put out by the Sub Atmospheric Technology Group of the Lower Limb Society of AAOP. It is a review of the principles and methods as related to transtibial fittings. It is instructional and also answers many of the questions regarding the topic and even offers CEUs if you take the quiz. It is a MUST READ!!