There is a lot to consider when prescribing tilt-in-space manual wheelchairs. This includes:
- the clinical reasons for selecting such a wheelchair
- the differences between various tilt wheelchairs, including the mechanism of tilt
- the implications for the differences between tilt models on pressure management, tilt performance, wheelbase, maneuverability, and potential for independent propulsion
- the degree of tilt required for pressure management versus positioning
- the frequency and duration of tilt required for pressure management.
Past Clinical Corner articles have addressed many of these considerations. Let's review the content and expand on some of the considerations in this month's Clinical Corner article.
The Evidence on Tilt, Recline and Elevating Leg Supports This 2017 Clinical Corner article cited the Rehabilitation Engineering and Assistive Technology Society of North America (RESNA) Position on the Application of Tilt, Recline and Elevating Legrests for Wheelchairs: 2015 Current State of the Literature document to outline the clinical benefits of the use of tilt, recline and elevating leg supports. It should be noted that the clinical reasons for the use of tilt, recline and elevating leg supports that are outlined in this paper apply to both manual and power wheelchairs.
This article also reviews the evidence related to the degree of tilt required for pressure management.
Weight Shifting and Pressure Management 2.0 This 2018 Clinical Corner article reviews the recommendations from clinical practice guidelines with respect to weight shifting and repositioning for pressure injury prevention (e.g., the frequency and duration of tilt required for pressure redistribution).
The Science of Manual Tilt Mechanisms In 2015, this Clinical Corner article described what is meant by displacement of centre of gravity in various degrees of tilt. The article also outlined how the mechanism of tilt in a manual tilt-in-space wheelchair affects the potential for centre of gravity displacement, and the resulting effects on the overall wheelbase and maneuverability of the wheelchair, and the effort required to move a person in and out of tilt.
While it is important to understand the mechanism of tilt, it is not the only factor to consider when comparing models of tilt-in-space wheelchairs. Another consideration is the tilt range and its effect on pressure redistribution. Various tilt ranges occur amongst the different models of tilt-in-space wheelchairs. Some models of tilt wheelchairs have a maximum of 30 degrees or less in tilt; while others have a maximum range of 45 or 55 degrees of tilt. This will have an effect on pressure redistribution. (Refer to The Evidence on Tilt, Recline and Elevating Leg Supports for information on the degree of tilt required for off-loading.)
Another factor to consider when differentiating between models of tilt-in-space wheelchairs is the need for certain features. Features, such as a dynamic back, contracture rigging, a vent tray or a one-arm drive, are not available on all models of tilt wheelchairs. The need for certain features will direct the selection away from some models of tilt-in-space wheelchairs and towards other models that have the necessary features.
Weight capacity may be another consideration. Different models of tilt-in-space wheelchairs have different weight capacities; e.g., 265 pounds, 275 pounds, or 300 pounds for standard and 400 pounds for heavy duty. One must be cognizant of the weight capacity of the wheelchair and the client's current weight. The stability of a client's weight should also be considered. If it is believed the client may gain or lose a significant amount of weight, such that the size of a needed wheelchair would be effected, it is important to consider a model of tilt-in-space chair that allows for retrofitting to re-size the wheelchair. Depending upon the model/design of the wheelchair and the manufacturer, the parts to grow/shrink a tilt-in-space wheelchair may be provided free of charge from the manufacturer within a specified period of time (e.g., within five years of original ownership of the wheelchair).
Front seat-to-floor height may be another factor that leads a clinician to select one model of tilt-in-space wheelchair over another. For example, a low seat-to-floor height may be required for independent transfers or for foot propulsion. Different models of tilt-in-space wheelchairs have different ranges in seat-to-floor height, with at least one model requiring no change to the front casters or forks to achieve different front seat heights. This is why understanding the technology available is part of best practice in seating and mobility. (For more on Best Practices in Seating and Mobility Assessments, click here for the Clinical Corner article.)
Another consideration in selecting between different models of tilt-in-space wheelchairs may be portability. For example, some pediatric models of tilt-in-space wheelchairs are foldable, which helps in terms of being able to transport the wheelchair in the trunk of a vehicle. For individuals who must remain seated in their wheelchair during transit, it is important to consider whether the wheelchair has been crash-tested for occupied transit.
This month, we have looked at tilt-in-space wheelchairs and the factors that differentiate different models. It is by understanding the differentiation that the most appropriate model can be prescribed for an individual. In addition, we have reviewed sources that outline the tilt/recline angles required for pressure redistribution and the frequency and duration of weight shifting required for off-loading.