A team-based care approach that involves an interdisciplinary team of rehabilitation professionals, patients, and relevant family members or caregivers should be implemented to address issues such as assessment, prescription, training, product delivery, and functional outcomes of a wheelchair user.
Medical and Physical Assessment
The physiatrist’s role includes assessing, documenting, and sharing with the team the underlying medical conditions that require a prescription for a wheelchair. Factors to be considered include patient’s age, disease prognosis, pain, obesity, cardiopulmonary or musculoskeletal problems, genitourinary or gastrointestinal problems, alterations in mental status, overall cognitive capacity, and risk for falls. Potential risks and secondary injuries, such as pressure ulcers, postural deformities, or upper limb repetitive strain injuries, associated with the use of equipment must also be assessed and considered. Comprehensive assessment includes physical-motor assessment of strength, range of movement, coordination, balance, posture, tone, contracture, endurance, sitting posture, trunk stability, cognition, perception, and use of external orthoses. Assessment of pelvic alignment is crucial because the pelvis serves as the base of all seating supports. Pelvic obliquities and spinal deformities need to be accommodated to facilitate sitting tolerance. The individual’s preference for different seated postures, even if they do not appear to be technically correct, must be considered. Other crucial measurements include hip and knee range of movement, especially when seated.
Functional Assessment
Functional mobility assessments in the areas of self-care, reach, access to surfaces at various heights, transfer to various surfaces, and functional mobility in the user’s natural environment should be incorporated in the overall assessment as the clinical setting is often very different from the natural or home setting.
Environmental Assessment
The user’s role, interest, responsibility, and occupation in his or her environment need to be understood in the assessment and prescription process. Physical accessibilities within the home, work, school, or other areas of the community often have a major impact on the feasibility of wheelchair and seating system options. A thorough assessment and survey of the home, usability of the equipment in the occupational environment, and identification of barriers and facilitators is warranted when determining which mobility equipment options are most appropriate for the user.
Assessment Tools
Anthropometrics
Rehabilitation professionals use calipers, rigid and soft tape measures, goniometers, scales, and digital cameras for comprehensive anthropometric measurements. These measurements are then translated into specific dimensions of the wheelchair and seating system.
Propulsion Analysis
Propulsion analysis is crucial for maintaining the long-term health of an individual by minimizing the likelihood for the development of upper limb pain and injury. Assessment tools include the wheelchair propulsion test using a stopwatch; tape measure; clinical observation; the SmartWheel protocol that uses force, torque, and distance-measuring pushrims; and clinical observation.
Pressure Analysis (eSlide 14.1)
Pressure analysis is used to set up the seating system, train individuals on proper pressure-relieving techniques (through biofeedback mechanisms), compare seating systems, and document the change in sitting tolerance over time. In addition to clinical observations and impressions, a pressure mapping system is used to provide a quantitative mechanism for measuring the pressure-relieving properties so that the likelihood of developing pressure ulcers and postural deformities is minimized.
Wheelchair Skills
The wheelchair skills test provides a quantitative method for assessing the ability of an individual to use a wheelchair in all domains of mobility and activities of daily living. Wheelchair skills assessment is important in determining the appropriate type of mobility, whether a person has the physical and cognitive capacity to use a wheelchair, and for training on the proper use of the wheelchair and seating system.
Wheeled Mobility Devices
There is a wide range of wheeled mobility devices, which can be divided into manual, powered, hybrid, and scooter types. The key features, indications, contraindications for use, and the available technologies are described below and in the accompanying tables and eSlides.
Manual Wheelchairs (eSlide 14.2)
Manual wheelchairs for daily use are often categorized by their design features and costs. The standard wheelchair is designed for short-term hospital or institutional use and is not recommended as a primary mode of mobility. A “hemi” wheelchair enables lowering of the seat-to-floor height to allow people to propel their wheelchair with their feet. Lightweight wheelchairs are designed for long-term use by individuals who spend less than a couple of hours each day in a wheelchair. Pediatric wheelchairs may have adjustable frames or kits for accommodating the growth of the child. Active, full-time users with good upper limb function and endurance should use ultralight wheelchairs. Hybrid wheelchairs are available for people with impaired upper limb function or endurance or those who require frequent use of ramps or hilly terrain.
Basic Wheelchair Components and Anatomical Dimensions (eSlide 14.3)
Accurate anatomic measurement has a direct impact on the overall assessment and prescription of the wheelchair and seating support system. Maximizing the mobility of an individual while he or she is using the wheelchair and seating system is dependent on properly matching the anatomic dimensions of the person to the wheelchair dimensions. The seat should be high enough to accommodate enough space under the footrests to clear obstacles and should have enough knee clearance to fit under tables, counters and sinks, as well as have steering wheels or hand controls for those who drive. Adequate seat depth and width are needed to support the thighs and the widest part of the buttocks to prevent high sitting pressures and development of pressure ulcers behind the knees, calves, and pelvic bony prominences. The backrest should be low enough to provide adequate postural support but still allow the upper limbs to have good access to the pushrims for effective wheelchair propelling. Ideally, backrests should allow attachment of different types of back supports. Correct armrest height is important to allow good support to the upper limbs and shoulders, as well as provide good access to the pushrims.
Adjustments and Customization
The main advantage of using ultra-lightweight wheelchairs over other wheelchair types is their high degree of adjustability and customization, which results in optimization of wheelchair fit and propulsion biomechanics.
Seat and Back Angle Adjustments
Seat and back angle adjustments, separately or together, optimize the postural support and comfort for an individual. Adjusting the seat so that it slopes downward toward the rear of the wheelchair (seat dump) can assist people with limited trunk control by stabilizing their pelvis and spine, making it easier to propel the wheelchair. It can decrease extensor tone and posturing. However, excess seat dump increases pressure on the sacrum, increases the risk for skin breakdown, and makes it more difficult to transfer into and out of the wheelchair. An increased back angle or a reclined back might be needed when the person’s hips do not flex well or gravity is needed to assist with balancing the trunk.
Rear Wheel Camber (eSlide 14.4)
Camber is the angle the wheel makes from the vertical axis. Most wheelchairs generally do not have more than 8 degrees of camber.
Rear Axle Position
The placement of rear wheels relative to an individual’s upper limbs directly affects propulsion biomechanics and therefore the likelihood of upper limb pain and injury.
Horizontal and Vertical Axle Positions (eSlide 14.5)
A more forward axle position requires less muscle effort because rolling resistance is decreased when more weight is distributed over the larger rear wheels than over the smaller front casters. This position also facilitates performing a “wheelie,” negotiating obstacles, and ascending or descending curbs. Because of the effects on stability, the axle should be moved forward incrementally with input from the wheelchair user. Adding weight to the chair can also affect stability and maneuverability of the wheelchair. Therefore packages or backpacks should ideally be located underneath the seat of the wheelchair. A lower seat position can improve propulsion biomechanics by increasing hand contact with the pushrims, thereby lowering stroke frequency and increasing mechanical efficiency and stability of the wheelchair. If the seat height is too low, however, the patient has to push with the shoulders abducted, which increases the risk for shoulder impingement.
Amputee Axle
People with lower limb amputations might need to have their axles adjusted farther back than those without amputations to increase the stability of the wheelchair. This is because of the loss of the counterbalancing weight of the lower limbs. However, a rearward axle position can have serious negative effects on shoulder biomechanics.
Power Wheelchairs (eSlides 14.6 and 14.7)
Power wheelchairs provide a flexible platform for mobility when a manual wheelchair or power-assist wheelchair no longer meets the unique characteristics of an individual ( Table 14.1 ). Power wheelchairs can be grouped into four broad categories on the basis of their features and intended use. The power drive wheel location must be appropriate for the user’s lifestyle and environment. The mobility of an individual is optimized by aligning his or her needs with the characteristics of each configuration.
| Features | Indications | Disadvantages | |
|---|---|---|---|
| Basic power wheelchairs | Simple electronics Standard proportional compact joystick For indoor use: small wheelchair footprint (i.e., area connecting the four wheels) for greater maneuverability in confined spaces | For light use on indoor surfaces Appropriate for limited indoor use for individuals with a short-term disability who have good trunk control and do not need specialized seating | Limited seating options Low quality |
| Folding and transportable power wheelchairs | Designed for disassembling to facilitate transport | Typically used by individuals with reasonably good trunk and upper body control | Might not have the stability or power to negotiate obstacles outdoors |
| Combination indoor–outdoor power wheelchairs | Support simple to advanced controllers, a wide range of input devices (e.g., proportional and nonproportional), and power seating options (e.g., tilt, recline, leg rests) May incorporate drive wheel suspension to reduce road vibrations May be equipped with rehabilitation seating, which allows for the attachment of modular seating hardware (e.g., backrests, cushions, laterals, hip guides, and headrests) | For individuals with long-term disabilities Designed for use on indoor surfaces and finished surfaces (e.g., sidewalks and driveways) in the community | Bulky |
| All-terrain power wheelchairs | More powerful motors, drive wheel suspensions, large-diameter drive wheels with heavily treaded tires, or four-drive wheels for climbing obstacles and traversing rough terrains Capable of faster speeds and offer greater stability on steeper inclined surfaces | For use by people who live in communities without finished surfaces | Bulky Not suitable for indoor use |
| Power drive wheel location | |||
| Rear-wheel drive | Large drive wheels in the rear and small pivoting casters in the front Rear-wheel drive power wheelchairs steer and handle predictably and naturally track straight Most appropriate drive configuration for high-speed applications | In general, preferred by people who drive with special input devices (e.g., chin joystick and head array) or have reduced fine motor coordination because of its consistent tracking | Limited obstacle climbing by the small front casters Large turning radius |
| Mid-wheel drive | Drive wheels are located near the center of the power wheelchair Increased indoor maneuverability The most effective drive for both ascending and descending obstacles for skilled, practiced users More compact footprint and a tighter turning radius | For a more active wheelchair user who requires indoor and outdoor capability on uneven terrain | Possibility of getting “stuck” on the front or rear casters, which can suspend the drive wheel in midair with no contact to the ground |
| Front-wheel drive | Large drive wheels in the front and small pivoting casters in the rear Very stable setup for uneven terrain and hills Best capability to climb forward over small obstacles Overall, turning radius is smaller than that of rear-wheel drive but larger than that of the mid-wheel drive power base | For a more active wheelchair user who requires outdoor capability on an uneven terrain | Earlier models had a tendency for the back of the chair to wander side-to-side (“fishtailing”), especially with increased speeds |
Input Methods and Programmability (eSlide 14.8)
The most common input device is a joystick that is programmed for proportional control. If an individual cannot use a joystick, alternative controls include mechanical switches, pneumatic switches, fiber optic sensors, and proximity sensors, which are placed at the head, chin, or foot.
Wheelchair Performance (eSlide 14.9)
Wheelchairs that are less prone to failure are safer for the users. It is reported that component failures and engineering factors are responsible for 40%–60% of the injuries to power wheelchair users.
Seating Principles
Proper positioning of the pelvis and trunk provides a stable base for the upper limbs to prevent upper limb overuse and injury. Without proper base positioning, the head and neck will not be well aligned with the spine. The pelvis should be stabilized on a cushion that provides postural support as well as optimal pressure distribution. The cushion should be mounted on a hard surface that maintains its position. The seating system needs to accommodate the pelvis and trunk in positions other than neutral. Proper positioning and support of the head and neck facilitate proper breathing and swallowing and can prevent excessive strain of the head and neck stabilizer muscles. Tilt and recline systems should always be equipped with a headrest to support the head when adjusting seat orientation and back angles. Additional seating considerations are needed for patients with sensory loss, paralysis or paresis, contractures, or spasticity and high tone.
Wheelchair Seating and Cushions (eSlide 14.10)
Wheelchairs are equipped with a solid seat pan or sling seat. A solid seat pan facilitates long-term performance of the seat cushion. Wheelchair cushions consist of various materials, such as foam, air, gel, and composites. They are divided into five categories: (1) general use cushions, (2) skin protection cushions, (3) positioning cushions, (4) skin protection and positioning cushions, and (5) custom-molded cushions. Comfort, stability, and pressure relief are important factors when selecting a cushion. As a result of tissue compression and circulation impairment, paralysis, loss of pain and pressure sensation, and the inability to relieve pressure increase the likelihood of developing pressure ulcers. Components such as adductor and abductor pads, hip guides, positioning belts, and transfer handles can be added to the wheelchair or cushion for increased postural support.
Back Supports (eSlide 14.11)
Manual chairs are equipped with sling backs, and most power chairs are equipped with seat canes for the attachment of back supports. There are four categories of back supports: (1) general use backs, (2) positioning backs, (3) skin protection and positioning backs, and (4) custom-molded backs. Back supports are typically planar, contour, or custom-made and are available in different varieties, such as foam and combinations of foam plus gel or foam plus air.
Seat Functions (eSlide 14.12)
Tilt and recline functions enable pressure distribution management. Seat elevators improve the reaching capability, increase independence, and enhance social interaction.
Other Wheelchair Essentials (eSlide 14.13)
Other wheelchair essentials that support the user’s posture and comfort, ease of use, safety, and stability include armrests, headrests, laterals and harnesses, front riggers, wheels and tires, casters, wheel locks, pushrims, lever devices, and antitippers ( Table 14.2 ). The ability to effectively propel the wheelchair depends on the physical capabilities of an individual; the weight, quality, and setup of the wheelchair; and the propulsion technique. The prescription of these essential items and that of optional and additional items should be discussed with the patient so that an informed decision is made on the basis of the patient’s needs.
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