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Groundbreaking Research Uncovers New Insights for Reducing Deadly Pressure Ulcers in Wheelchair Patients

Study shows air cell cushions are 10,000 times better than standard foam for preventing deep tissue injury 

ST. LOUIS, December 10, 2014 ROHO, Inc., a leader in wheelchair seating solutions since 1973, today announces research findings that recognize adjustable air cell cushions as medically superior for reducing deep-tissue injuries and skin breakdown1, which can lead to deadly pressure ulcers and costs the American healthcare system billions of dollars per year.2

The study, conducted by Dr. Amit Gefen of Tel Aviv University, provides new clinical data to guide recommendations for the best cushions to protect people who use wheelchairs for mobility. The new study is the first to offer a comparison between two commonly used wheelchair cushion technologies – foam-based (representing the largest number of cushions in use) and ROHO’s air-cell technology.

The Issue: 

Pressure ulcers are a serious public health issue: fast to develop, extremely expensive, hard to heal and potentially fatal. In the U.S., nearly 60,000 patients die each year from complications linked to hospital-acquired pressure ulcers3 – almost twice as many deaths as from motor vehicle accidents.4 The cost to treat one single full-thickness pressure ulcer is about $70,000.2

As deadly and costly as pressure ulcers can be, they remain a daily concern for the 3.6 million Americans who use wheelchairs for mobility.5 But Gefen’s groundbreaking research is changing that.

Dr. Gefen and other leading researchers around the globe found that cell deformation was the cause of deep-tissue injury (DTI), starting deep and invisible – from the inside out. Prior research pointed toward skin breakdown and constricted blood flow as a leading cause. This study was the first to apply this knowledge to a direct comparison between different types of wheelchair cushions.

“Our study revealed an important insight about the best ways to minimize these deformations – and therefore DTIs – in wheelchair users,” said Gefen. “Adjustable air cell cushions were far superior over foam and could be the key to helping avoid pressure ulcers. The findings are significant not only because of the size of the wheelchair users’ population, but also because of the healthcare system’s cost in treating pressure ulcers – more than $11 billion annually in the U.S. alone.2

Study Methods and Results: 

The study used seated MRIs and “finite element” computer modeling to unlock a new picture of the damage that causes deep- tissue injuries.

  • Gefen’s team compared the ROHO® QUADTRO SELECT® HIGH PROFILE® cushion and two flat, foam-based cushions with varying stiffness properties (7 kPa and 10 kPa) for individuals with a spinal cord injury (SCI).
  • The study used an MRI slice from a 21-year-old SCI patient to develop an anatomically-realistic model of the patient’s left buttock.
  • For all three cushions, immersion was calculated as the percentage of skin surface in full contact with the cushion. Higher figures represent more surface area for load transfer, and potentially lower internal tissue loads.
  • The different mechanical stresses – compressive, tensile, shear and effective stress – were calculated.
  • Measures were recorded for each individual model, in the muscle, fat, and skin tissues under the ischial tuberosities during sitting, to determine the risks for the specific internal conditions.
  • For ROHO’s air cell cushion, immersion was consistently in the 91-93 percent range; for the foam cushions, the range was 58-65 percent.

Results demonstrated significant evidence that skin breakdown risk is much lower for ROHO adjustable air cell cushions compared to non-adjustable foam cushions. In fact, the study revealed that air cell cushions are 10,000 times better than foam in reducing tissue damage that can cause death.

Moreover, bone flattening led to higher peak stresses on muscle tissue in the foam cushions, but lower stresses for the air cell cushion. Likewise, muscle atrophy substantially increased fat and skin stresses on foams, but substantially decreased them on the air cell cushion. Both of these sets of results demonstrate that as the patient’s condition advanced, the air cell cushion decreased the risk even further in comparison to a foam support.

“The Gefen study proved what ROHO has believed for 40 years: Air cell cushions that ROHO pioneered prevent deformation through immersion and envelopment,” said Tom Borcherding, president of ROHO. “ROHO is committed to leading the industry in developing the science to improve the lives of people that use wheelchairs for mobility, and we drive U.S. and international standards that our competitors do not. This new and groundbreaking work is already providing the evidence for a critically needed change in direction, toward prescribing better and safer sitting solutions. ”

About ROHO ROHO, Inc. is a leading global wheelchair cushion manufacturer. Specializing in seating solutions with shape fitting technology® since 1973, ROHO manufactures and distributes a variety of standard and custom-size wheelchair cushions and accessories, back systems, and support surfaces. Made in the United States for over 40 years, ROHO provides outstanding manufacturing controls for proven and consistent quality. For more information, please contact customer service at 800-851-3449.


1   Ayelet Levy, Kara Kopplin, Amit Grefen. An air-cell-based cushion for pressure ulcer protection remarkably reduces tissue stresses in the seated buttocks with respect to foams: Finite element studies. Journal of Tissue Viability (2014) 23, 13-23.

2   Duncan KD. Preventing pressure ulcers: the goal is zero. Jt Comm J Qual Patient Saf 2007;33(10):605e10.

3   Lyder, C. (2003). “Pressure Ulcer Prevention and Management.” Journal of American Medical Association 289: 223-226.

4   National Highway Traffic Safety Administration (2012, January 1). Retrieved September 11, 2014, from

5.  U.S. Census Bureau, Americans with Disabilities 2010.

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