This is how amazing iShear works

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Why measure TSF?

In clinics worldwide sliding has always been reported as a major problem in wheelchair seating. [1] Shear forces will increase as the ischial tuberosities are slowly moving forward due to a posterior tilted pelvis. [2] The occurrence of TSF may indicate that a person sitting in a wheelchair will slide over time. The higher the TSF, the more likely this is. Measuring magnitudes of TSF when setting up or adjusting a wheelchair can help minimize the risk of sliding.

A solution to a clinical challenge

Sliding often occurs hours or days after a wheelchair setup and often requires a follow up visit to re-adjust the seating system. It was always difficult to quantify and measure sliding or shear forces, which made it hard to compare different wheelchair set-ups or document different seating interventions. This is why sliding and shear have been a real clinical challenge… up to now. Now there is iShear.

Comparing wheelchair set-ups and seating interventions

iShear allows you to monitor and record the impact that a certain wheelchair set-up has on the quantity of TSF. You can easily monitor and compare the occurring TSF while adjusting or selecting a back support system, back recline angles, seat angles, tilt in space, foot supports, different seat surfaces, secondary positioning systems, seating accessories… etc. etc.

Monitoring over time

iShear makes it possible to monitor and record the TSF in a wheelchair set-up and it can be set to continue to do this for hours after the initial set-up. Observing the client without the necessity of being present during the session. This allows you to observe the client without the necessity of being present during the session.

Educating clients and caregivers

iShear can be used as an instrument to help educate clients and caregivers about the correct use and set-up of the wheelchair. Help them understand the effect of the use of recline and tilt, of changing foot support angles or changing the seat depth. You can show the client in detail the consequences of an incorrect transfer. iShear helps you to justify adjustments to the seating system or to the wheelchair set-up. iShear can be easily used together with a pressure mapping system.

Research total shear force in the seat plane

iShear may help assessing the risks of amounts of TSF in relation to skin integrity.
Several studies show that when shear stress is applied to skin tissue it reduces or even blocks blood flow in the tissue layers, potentially leading to soft tissue breakdown. With high levels of shear stress, only half the amount of pressure is required to cause blood vessel occlusion as when little shear stress is present [3]. So shear is an important factor in the development of pressure ulcers, but has been hard or rather impossible to quantify. As iShear can measure total shear force in the seat plane, it is a great tool to help research the effect of shear.

Wound development and shear

Alongside pressure redistribution, patient repositioning, patient mobilization and microclimate management, strategies to reduce shear stress form an important part of reducing a patients’ overall risk of pressure ulcer development.

Shear reduction guidelines are included in the recent guidelines produced by the NPUAP and EPUAP [4]. Up to now it was impossible to quantify shear. iShear can help you to do just that.


1. R. Aissaoui, M. Lacoste, and J. Dansereau, “Analysis of sliding and pressure distribution during a repositioning of persons in a simulator chair,” IEEE Transactions on Neural Systems and Rehabilitation Engineering, vol. 9, pp. 215- 223, 2001
2. Kemegaya, T., (2016). Influence of sacral sitting in a wheelchair on the distribution of contact pressure on the buttocks and back and shear force on the ischial region. J Phys Ther Sci, 2016; 28(10): 2830-2833
3. International review. Pressure ulcer prevention: pressure, shear, friction and microclimate in context. A consensus document. London: Wounds International, 2010.
4. National Pressure Ulcer Advisory Panel, European Pressure Ulcer Advisory Panel and Pan Pacific Pressure Injury Alliance. Prevention and Treatment of Pressure Ulcers: Quick Reference Guide. Emily Haesler (Ed.). Cambridge Media: Osborne Park, Australia; 2014.