Ultralight & Manual Wheelchair Case Studies
"The First Chair I Sit Into Rather than on Top Of"
Even decades post injury, efficient self propulsion was not a major everyday concern for Steve Kearley, 43, an ultralightweight wheelchair user. A three-time Paralympian in quad rugby, Steve still plays on a local team, so strength and stamina issues weren’t necessarily at the top of his list of concerns as he sought out his next wheelchair.
To find the best possible seating & mobility system, Steve worked with Brandon Edmondson, OTR/ATP, director of clinical sales for Permobil and TiLite, and Jim Black, TiLite sales management. And they identified a number of factors to consider:
- Steve works for a urological supplies company and is in and out of his sedan multiple times a day — so wheelchair weight is “of utmost importance.”
- Steve has had just one pressure ulcer, resolved via surgery four years ago. The ulcer was on an ischial tuberosity (IT) and started “with an abrasion from a bad transfer.”
- Brandon noted, “Steve has a natural tendency to slide into posterior pelvic tilt and a lumbar kyphosis, especially when self-propelling. Although his current chair was functional, it required him to constantly reposition due to sliding forward in the system. “He also required 3.5" of seat slope for adequate stability, and the seat-to-back angle this created made it impossible to provide any lowback support. The aggressive seat slope also encouraged his posterior pelvic tilt; however, without it he was at constant risk of forward instability. Steve also has atrophy in his lower extremities, and even with a properly fitted rear seat width, his lower-extremity positioning was a concern. He found himself having to stop and readjust his legs on the footplate after negotiating bumps and terrain. He also was looking for help with the front stability of the entire system. His previous chair would pitch forward when negotiating steep declines, and weight was suddenly transferred to the front casters.”
- While propulsion wasn’t the first issue the team addressed, Brandon added they wanted to be sure “rear wheel placement is optimal and he has a friction handrim [so] his push efficiency is effective. We aimed to make it as efficient as possible, considering he is now 25 years post, and any reduction of repetitive strain is vital.”
Creating the Solution
Steve and the team ultimately chose a TiLite TR with Ergo seat and seat taper modifications.
“We chose the TR over an openframe design like his last chair due to weight and wanting to maximize the push efficiency of the frame,” Brandon says. “The triangulation provides rigidity that cannot be matched in an open-frame design.”
From there, the team drilled down to the details that would make Steve’s chair uniquely and efficiently his own. “We used a CAD drawing created off the order form to make some changes to his specs while monitoring the effect on some key measurements,” Brandon says. “For example, Jim Black has been teaching about frame depth and its benefits for a few years now. We wanted to extend [Steve’s] frame depth several inches past his seat depth (sling depth) in order to give Steve the front stability he was looking for. The CAD allowed us to see exactly how much frame depth we could add without affecting his functional footprint (back of rear wheel to front of frame).
“We moved his rear-wheel center of gravity forward a bit and were able to make his seat depth 15" and his frame depth 17.5" without growing his functional footprint. We wanted to stay at or below 31", as we knew this worked in all his environments. We also tapered his seat to match his body measurements and help him maintain his lower-extremity positioning throughout the day.”
To address postural issues, Brandon said, “The biggest thing we did for Steve is an Ergo seat. The Ergo seat provides stability without sitting the pelvis on a posterior seat slope. If you look at the pictures, Steve was able to drop straight down into the system and sits with a more neutral pelvis. His femur runs perfectly flat rather than on a slope now, which has helped his posture. We actually kept his front and rear seat height measurements the same, but because he can fully slide back into the system, his center of gravity is lower. He gets better back support and is not sliding out of the system and having to reposition. Although his previous chair had a 15" rear seat height, he was actually sitting closer to 16" because his closed back angle wouldn’t allow him to get all the way into the system.”
A Brand-New Outcome
Did all that fine-tuning pay off?
Steve has been using the TR for several months, and Brandon reports, “He stated, ‘This is the first chair I have ever felt like I sit into rather than on top of.’ He has reported better efficiency with propulsion, as his casters are further forward and therefore unweighted. He also reports significantly better balance and front stability in the chair due to the Ergo seat and lowering of his center of gravity combined with the frame depth addition.
“He also reports less lower-extremity repositioning throughout the day due to the frame matching his body. One unexpected outcome was a reduction in pressure on his ITs. We show more proximal loading in the thigh area due to the shape of the Ergo bend — and while we can’t expect this for every client, it was definitely an added bonus. Steve is a living example of what we call TiFit — building and thinking of the chair like a wheeled prosthetic.”
As for what he and Jim learned from creating this new system for Steve, Brandon says, “Although it is sometimes easier to duplicate past specifications, we were able to make some changes with Steve’s blessing and create a better outcome.”
This article originally appeared in the February 2015 issue of Mobility Management.