When An Elastomer Goes Flat… The Story of J and the Flattened Elastomers

Jill Sparacio, OTR/L, ATP/SMS, ABDA

Clearly, Something Was Different

Some basic items need to be routinely checked when using dynamic wheelchair components. Usually the idea of routine “maintenance” worries me, however what I found can be easily checked.

This is the story of J and the flattened elastomers. J is a young man with an incredibly strong extensor tone pattern that usually initiates in his hips. He uses a Seating Dynamics Dynamic Rocker Back to absorb these forces. He resides in a long term care facility and has multiple caregivers who have known him for many years.

I was receiving complaints from his caregivers that he “just doesn’t look right in his wheelchair anymore”. When passing him, I also noticed that he was no longer sitting on his seat. Instead, his feet were firmly planted on his footplates, with hips extended and his buttocks lifted off of the seat. His arching/extension pattern had returned. At times, the staff were unable to get his feet on his footplates due to this extension. Others commented that he sat much better if his feet were left hanging off the front edge of his footplates. Observation revealed a more exaggerated, compromised posture with his hips far forward on his seat.

Bottom line, something was different.

Diagnosing The Problem

First, I double checked to make sure that the Dynamic Rocker Back hardware was not “locked out. ” Once I found those to be open, I realized that there was no longer any tension in the dynamic mechanism. The rear canes were opened as far as the elastomer would allow, however no resistance was present to return J to an upright position. The back canes could be manually pushed back into alignment, but would not remain in that position.

Investigation revealed that the elastomers were compressed and asymmetrical, rendering them useless.

The height difference between the flattened elastomers and a new set was 3/8” (see Figure 1). In measuring the impact of these compressed elastomers, changes in the seat to back angle were noticed.

Originally, the desired seat to back angle was 100 degrees. With the flattened elastomers, the seat to back angle was a constant 108 degrees (see Figures 2 and 3 below). Eight degrees were more than enough to alter J’s desired seat to back angle and elicit his extension pattern.

In order to remedy this problem, the elastomers needed to be replaced.

Fixing The Problem and Positive Changes for J – In Only 20 Minutes!

Although I work with several excellent suppliers, I didn’t want to wait for a scheduled wheelchair clinic to complete this repair for J. After locating some extra elastomers along with detailed instructions for replacement, I proceeded to take the old elastomers out to determine if these were the problem. Once removed, I found them to be very distorted in both height and shape (see Figure 1). Once the new elastomers were installed, the desired 100 degree seat to back angle was restored.

All in all, it took about 20 minutes (using the easy to follow directions).

I changed the Clear elastomers (which provide a Medium level of resistance) with Green elastomers (which provide an Extra Firm level of resistance). J was still able to move the dynamic back and the firmer elastomers should withstand the forces J exerts even better than the Clear elastomers.

When J extended, the movement that resulted from the compression of the elastomers (absorbing and diffusing the force) and the subsequent rebound was again effective at decreasing his extensor pattern.

Once his tone was not met with firm resistance, it naturally dissipated, allowing his hips to return to flexion.

The Moral of the Flattened Elastomer

So what did I learn from this? Check the elastomers!

The 20 minutes it took to change out the elastomers were well worth the positive changes that resulted in J’s posture.

Figure 2: Old, clear elastomer

Figure 3: New, green elastomer

Notice the height difference of the exposed elastomer; the shorter height of the old elastomer resulted in a more open seat to back angle. Due to the compressed size, the old elastomer has no ability to “rebound” or return the back canes to the desired position.

*Please be familiar with how the Dynamic Rocker Back mechanism works prior to disassembling! It is always best to rely on qualified suppliers to perform this work.

Click here for Elastomer Replacement Instructions

Achieving Head Alignment through Movement

Vince is a young adult with the diagnosis of cerebral palsy. He had significant muscle tone throughout his body and frequently extends in his current wheelchair seating system. We were anxious to explore dynamic seating options to diffuse some of this extensor tone. However, Vince had very little hip flexion or extension beyond his current seated position and, as a result, he could not benefit from a dynamic back which allows movement past this point. He had no knee extension past 90 degrees and his range limitations prevented him using even the telescoping feature of a dynamic footrest. We were unsure if we could provide any dynamic intervention when Vince broke yet another head support.

The Dynamic Head Support Solution

We decided to try a dynamic head support hardware. With the addition of this dynamic component, we found that Vince’s head was in an aligned position most of the time, rather than his typical hyper-extended position. He experienced less force through the cervical area, as well, which we hoped would protect his neck from injury and increase his comfort. His overall extensor tone and posturing improved when force was diffused at his neck. Finally, Vince has yet to break his head support hardware since “going dynamic”!

Using Combination Dynamic Seating Components

If Vince had adequate range of motion, we would have also recommended a Dynamic Rocker Back and Dynamic Footrests due to his extreme tone. In combination with Dynamic Head Support Hardware, this would have provided a very effective solution. Due to range limitations, Vince could only use the Dynamic Head Support Hardware. Even this lone dynamic component diffused forces, reduced overall tone and posturing, and improved head position.


Seating Dynamics Exhibited Dynamic Wheelchair Components at the Numotion NuFair, in Maryland

Michelle L. Lange, OTR/L, ABDA, ATP/SMS

On St. Patrick’s Day, we had the opportunity to participate in the Salisbury, MD Numotion NuFair. Approximately 45 therapists from the surrounding areas attended 3 CEU courses and the extensive exhibits.

Michelle Lange presented on Dynamic Seating and Seating Dynamics exhibited. The attendees were great and enjoyed learning more about this practice area!

Questions during the session had to do with wheelchair durability, funding, and shear forces. Look for upcoming Blogs on those topics and check out a past blog on molded seating and shear forces. Continue reading

Don’t Let This Workshop Go to Your Head! Wheelchair Headrests And Proper Head Positioning

Michelle L. Lange, OTR/L, ABDA, ATP/SMS

This is our third and last blog summing up a wonderful 2017 International Seating Symposium in Nashville. I had the privilege of presenting a workshop on the topic of “Positioning the Head.” A great group gathered in the ballroom in search of answers for those clients who persist with less than desirable head positions despite our best efforts.

Now, I tend to throw chocolate in my sessions, and I have a pretty good arm, but I could only throw about a third of the length of this room, so I encouraged folks to move up for chocolate – and to see the screen! Continue reading

Why I like ISS!

Greg Peek

President and Principal Designer, Seating Dynamics

Having attended all but five of the International Seating Symposiums since 1987, I can say that it has always been the greatest place on earth to learn about wheelchair seating, simple as that. The opportunity that I have had as a designer to meet and listen to people about the problems that they face on a daily basis is unbeatable. Those of you who know me undoubtedly know that I love a challenge and when someone explains a problem that has no solution, I don’t see it as a problem, but as an opportunity. Often I say, “I can fix that”!
Continue reading

The International Seating Symposium – a Dynamic Time!

Greg Peek, President, Seating Dynamics

Michelle L. Lange, OTR/L, ABDA, ATP/SMS

The Seating Dynamics van made the trek from Denver to Nashville in time to exhibit at the International Seating Symposium or ISS. Over 2000 people attended this event from all over the world! ISS offers great educational courses, an enormous exhibit hall, and wonderful networking. A good time was had by all! Continue reading

Dynamic Head Supports – the importance of design in meeting client goals

Michelle L. Lange, OTR/L, ABDA, ATP/SMS

In our last blog, we discussed clinical indicators and contra-indicators to allowing movement into neck extension using a dynamic head support. Dynamic movement in this area can protect the head support hardware from damage, limit client injury, and reduce overall extensor tone. How does design facilitate these goals? Continue reading

3 Reasons to Allow the Neck to Extend

Michelle L. Lange, OTR/L, ABDA, ATP/SMS

In previous blogs, we have discussed clinical indicators for providing dynamic movement at the hips and knees. Another location dynamic movement can be provided is at the neck through Dynamic head support mounting hardware. Most dynamic options allow movement into neck extension and then facilitate return to an upright and aligned posture. So when is a dynamic head support clinically indicated?  Continue reading

Preserving Joint Integrity through Dynamic Seating

Michelle L. Lange, OTR/L, ABDA, ATP/SMS

Daniel is a teenage boy with the diagnoses of cerebral palsy and seizures. He has significantly high muscle tone and has had varied success with tone management over the years. If his feet are not strapped to the footplates, he extends at his knees and his feet are then hanging far in front of the footplates. This increases the turning radius of the wheelchair, places his lower legs at risk of injury, and leads to a loss of position of his pelvis. As a result, his feet have been strapped into shoeholders for most of his life. This positioning has kept his feet on the footplates, but has created other issues. Continue reading