The data gathered during the physical examination, seating simulation, and wheelchair testing are now analyzed to determine equipment parameters based on specific client-centered goals. Discussion ensues to determine if the client is functioning at highest potential or if additional support would help to improve function of distal body parts.16,17 Each piece of equipment provided needs to be justified; for example, justification for lateral knee supports might be the need to maintain neutral alignment of the LEs or the need to prevent excessive active hip abduction. For each component required for postural support, mounting location, method of stabilization, strength, and durability must be finalized. For example, lateral trunk supports might be needed for postural support but will interfere with a sliding board transfer. Swing-away hardware will move the support out of the way, but the specific hardware to use is dependent on the ability of the client or caregiver to access the hardware and shift it out of the way. Testing of these details is important to ensure that maximal independence is achieved with the new equipment.
A problem solving approach can guide selection of needed seating features by using a sequence of(1) identification of equipment-related clinical problems; (2) establishing objectives for equipment intervention; (3) making equipment property recommendations; and (4) identification of equipment specifications.18,19 Box 32.1 provides an example of this strategy.
Box 32.1 Example of Problem Solving Model Grid
|Clinical Problems ||Objectives for Equipment Intervention ||Equipment Property Recommendations ||Product Specifications |
|Diagnosis of cerebral palsy (CP); fluctuating muscle tone with wide excursion, ataxic tremors on active movement, poor grading of movement, and poor ability to isolate muscle groups ||Increase stability through pelvis, trunk, and lower extremities (LEs) to improve upper extremity (UE) function ||Molded surfaces that provide maximal contact and control to increase body stability Stabilizing bar for left UE to improve function in right UE ||Determine specific molding system Determine final location for stabilizing bar and type of bar to use for maximal durability |
|Range of motion (ROM) limitations: hip flexion: 0-80°; knee extension with hip flex: 0-100°, ankle dorsiflexion with knee flexed: 0-0° (no motion), able to achieve good pelvic position, mild trunk scoliosis, good UE ROM ||Accommodate ROM limitations with seat to back support angle of 100°, seat to lower leg support angle of 80°, and lower leg to foot support angle of 90° to assist in maintaining pelvis in slight anterior tilt, level and not rotated and maintain symmetrical trunk alignment ||Adjustable-angle back hardware to accommodate hip ROM limitation Swing-away footrest system with angle-adjustable footplates to accommodate knee and ankle ROM Foot stabilizers to assist with maintaining stability and posture ||Adjustable-angle backposts Adjustable-angle footplates Shoe holders with hook-and-loop or D-ring closure for independence |
|Poor posture in current manual wheelchair, sits in posterior pelvic tilt, spine is kyphotic with mild scoliosis ||Achieve and maintain slight anterior pelvic tilt, level and not rotated Accommodate for mild scoliosis and maintain symmetrical trunk alignment Increase trunk elongation ||Medial knee support, pelvic positioning strap to stabilize pelvis, molded seat and back system for optimal control, support, and postural correction ||Medial knee support separate from molded seat for transfers Push-button pelvic positioning strap 1.5 in (3.8 cm) wide with flat mount (no grommets) Molded seat and back system |
|Propels manual wheelchair slowly for short distances only with wide excursion of movement and increased energy expenditure ||Increase independence in mobility by providing power mobility. Decrease energy expenditure and decrease wide excursion of movement ||Power wheelchair system with parameters that can be adjusted for ataxic movement, decreased movement control, speed, and acceleration Power base that provides increased foot/caster clearance ||Test various power wheelchairs to determine optimal base for driving and positioning Determine if able to achieve good posture throughout the day with one set position or if needs a tilt-in-space seating system |
|Requires supervision for transfers in and out of wheelchair ||Improve independence in ability to transfer in and out of wheelchair ||Accommodate leg length and ROM at knee and ankle Keep seat as low to floor as possible but maintain caster clearance Swing-away footrest system Flat seat surface for ease in getting on and off seat Flip-down medial knee support Adjustable-height armrests ||Swing-away footrests with angle-adjustable footplates ensuring access and independence with swing-away feature Flip-down medial knee support ensuring ability to move support out of way independently Adjustable-height armrests |
|Uses keyboard for computer independence ||Maintain independence in computer keyboard access ||Swing-away joystick mount to ensure access to tables ||Swing-away joystick mount ensuring ability to independently move it out of the way. |
|Uses urinal for independence in bathroom ||Maintain independence in bathroom ||Flip-down medial knee support ||Flip-down medial knee support ensuring independence |
It can assist in guiding the thought process and ensuring that all issues are addressed. This allows thoroughness and improves the ability to articulate reasons for choosing specific wheelchair components. The process is patient centered rather than product centered and will assist in obtaining optimal equipment.
Clinical Problems, Objectives, Property Recommendations, and Product Specifications
Information needed in this area includes data obtained from history, preliminary examination, supine and seated examinations, and determination of functional abilities to preserve and functional abilities to attain.
Goals should be set related to positioning and alignment, motor control, health, function, environmental issues, and social/emotion issues. Goals can be general (e.g., improve skin integrity) but will need to become more specific (e.g., reduce pressure under left ischial tuberosity to prevent pressure sores in this area) to determine equipment properties.
Consideration is given to the different surfaces and features of the equipment. Properties are the specific details of the final product. The surface shape and flexibility, dimensions, placement, and attachment features should be included in this section. Careful consideration of properties will ensure a final product that promotes optimal independence.
The list of property recommendations will be reviewed to determine the final product. If no commercial option is available with the needed properties, determination of a method to customize is needed. The supplier should be knowledgeable and be able to assist the therapist in obtaining the most appropriate equipment to address all needs.
The benefit of using this decision making process is to help keep the process client centered rather than product driven. It promotes problem solving and improves accuracy when choosing final product components.
When using this process, the person's diagnosis assists in determining specific properties of final equipment, as well as the priority of the properties. If working with someone with an SCI with previous pressure sore problems on the buttocks, the properties of the seat cushion become important. If working with someone with progressive MS, the ability to modify the equipment over time will be important. When considering the patient's medical diagnosis, it is important to determine if the condition is stable and if not, the type of changes that are expected. If the medical condition is stable but the person is newly injured (e.g., SCI), changes to equipment may be needed over time as the person adjusts to using a wheelchair for primary mobility purposes. If working with someone who is stable and has always done things one way, it is important to provide him or her with other options and determine if poor habits can be changed.
A well-planned seating system may be able to normalize tone, decrease pathological reflex activity, improve postural symmetry, enhance ROM, maintain and/or improve skin condition, increase comfort and sitting tolerance, decrease fatigue, and improve function of the autonomic nervous system. In addition, the base of the seating system can allow for changes in orientation in space (recline and tilt). A properly prescribed mobility base will improve access to the physical environment (both manual and power-activated), whether alone or with a caregiver. It should be effective for accomplishing all home, school, work, and recreational activities and, where necessary, assist the caregiver with patient management.
When setting priorities, it is important that clinical team members do not overload the patient with their professional opinions. Clinical teams may not be fully aware of the barriers facing the individual using a wheelchair in his or her physical environment. Clinicians may observe a patient ambulating in the clinic and feel that with added practice he or she could ambulate full time. This clinician may consider recommending crutches and a simple manual wheelchair. In the patient's real environment, however, long distances may need to be traversed to independently shop, attend community activities, and function at school or work. Walking to these activities would require extraordinary effort, and propelling a standard manual wheelchair may not offer much additional assistance. A motorized scooter or wheelchair may be more effective as a supplement for environmental mobility.
The components of the system that will directly affect comfort and maintenance of posture are the seat surface, back surface, pelvic positioner, UE surface, and LE surfaces. These areas should be addressed together as the postural support system. Increased contact between the user and the support surfaces increases comfort and control and decreases pressure over bony prominences.20,21,22,23 The continuum of available support surfaces runs from firm planar surfaces (wood, firm foam) (Fig. 32.13), through deformable surfaces (knit-covered foam) (Figs. 32.14 and 32.15), and contoured surfaces (Fig. 32.16), up to and including custom-molded surfaces (Fig. 32.17).
Patients seated on planar surfaces may show increased pressure over bony prominences.
Some types of foam will contour as a response to body weight.
An option for creating contoured seats is use of varying density (firmness) of foam.
Firmer foam shapes can be placed under a more flexible foam to create a contoured cushion.
Custom-molded cushions match the patient's body contours.
Angular relationships between the surfaces at the hip and knee joints (thigh and back surfaces, thigh and leg surfaces) previously determined during seating simulation must be included in final setup of postural support surfaces. This information will allow the planned intervention to accommodate limitations in ROM, ensure proper alignment of body segments, and minimize pressure distal to the joint. Changes of orientation in space (fixed or dynamic) affect the user's comfort level, pressure over skin surfaces, fatigue, and ability to work in gravity-minimized and gravity-influenced positions. Attention to these features will help ensure the success of the seating intervention. Appendix 32.A provides an overview of features of the wheelchair postural support system.
The seat support is the surface under the buttocks and thighs. A firm seat support is critical in creating good LE alignment, good pressure distribution, and improved comfort. Many basic manual wheelchairs come with sling upholstery. Over time, this type of surface creates poor pelvic positioning (Fig. 32.18). The hips tend to slide forward and the thighs tend to shift into hip adduction and internal rotation. Sling upholstery is used to increase the ease of folding the wheelchair. However, if the system is needed for more than transportation, a firm seat support should be added to the wheelchair. A solid seat board can be placed under the cover of a seat cushion to provide the firm base of support or a special seat pan (solid seat of metal or plastic that mounts directly to the seat frame or with attaching hardware to seat frame) can be added to the wheelchair once the upholstery is removed (Fig. 32.19).
Overall poor sitting posture and asymmetries created by a sling seat.
A firm sitting surface enhances sitting posture and provides a stable base of support.
Different seat supports have different properties. Foam, air, gel, combination types, and custom-shaped cushions are used to promote improved positioning, improved stability for UE activities, improved pressure relief, and improved comfort.24 The person should test various seat cushions to determine what system is optimal.
Properties of the seat that need to be considered include the surface shape, firmness, flexibility, dimensions, placement, and attachment features. The most critical dimensions include the seat depth and seat width. If the seat depth is too long, it promotes a posterior pelvic tilt and kyphotic spine posture. If the seat width is too wide, it will make propelling the wheelchair more difficult and if too narrow, increase pressure on the hips from the armrests and footrest system.
Box 32.2 provides a list of questions that should be considered when finalizing the seat support.
Box 32.2 Questions to Consider When Finalizing the Seat Support
Does the seat provide adequate support to promote good sitting posture?
Will the pressure distribution on the seat prevent pressure sores?
Is the shape of the seat cushion appropriate for the patient's body contours?
Does the person need a custom shape to accommodate deformities and maximize support?
Is pressure relief provided if the person is unable to complete weight shifts independently using UEs or through a tilt or recline option?
Is the seat depth an appropriate length?
Is the seat width appropriate for propelling the wheelchair and for comfortable positioning?
Is the seat surface appropriate for safe transfers into and out of the wheelchair?
Are special combinations of foam, air, or gel seat cushions needed to maximize comfort and pressure relief?
The back support is the surface behind the trunk. A firm back support is critical to promote good trunk posture and, in conjunction with lateral trunk supports, contributes to maintaining midline posture. Many basic manual wheelchairs have sling upholstery and this promotes poor trunk posture. There is an increased risk of a kyphotic spine and posterior pelvic tilt. The back support height can be varied depending on the needs of the individual. A shorter back may be appropriate for a person propelling the wheelchair with a taller back needed for a person who uses the tilt-in-space feature. A shorter back is more appropriate for a person with good trunk control and the ability to maintain good alignment without using lateral trunk supports. Back height is determined based on the person's trunk control, functional abilities, and comfort.
Different back supports have different properties. Foam, air, gel, combination types, and custom-shaped cushions are used to promote improved positioning, pressure relief, and comfort. The person should test various back cushions to determine what system is optimal.
Properties of the back that need to be considered include the surface shape, firmness and flexibility, dimensions, placement, and attachment features. The most critical dimensions include the back height and back width. Box 32.3 presents questions that should be considered when finalizing the back support.
Box 32.3 Questions to Consider When Finalizing the Back Support
Is the back support in an appropriate position for upright trunk posture (seat to back support angle, orientation in space)?
Is the back support an appropriate shape to fit the patient's body contours? (If using a commercially available back support with contour it should be examined to ensure the support will fit the person. At times, the patient's hips may be too wide to fit between the fixed lateral supports of a commercial back.)
Does the patient require a custom shape to provide full contact and support?
Does the back support provide adequate control for muscle weakness and trunk asymmetries?
Is the back comfortable when used in a tilted or reclined position?
Does the back support allow performance of functional activities (propelling, reaching, transfers)?
Is pressure distribution/relief adequate for a person with a bony spine, protruding sacrum, or to prevent pressure sores?
Are special combinations of foam, air, or gel needed to maximize comfort and pressure relief?
In addition to the seat and back support, other supports might be necessary to ensure optimal positioning, pressure relief, and comfort, including lateral trunk and hip supports, lateral and medial knee supports, head and foot support, anterior chest and UE support, and pelvic support.25 When determining the need for the support, consideration should be given to surface shape, firmness and flexibility, dimensions, placement, and type of attachment.
A belt or more rigid pelvic positioner may be needed to maintain good pelvic position (prevent the hips from sliding) and/or for safety.26 The direction, angle of pull, and number of anchor points of the belt is important.27
For example, if one hip tends to pull forward consistently, it may be useful to have the belt tighten by pulling it down toward that hip. The angle of pull to the seating surface should normally be 45° to 60° (Fig. 32.20).26 Some patients respond well to belts that form a 90° angle with the sitting surface. This pull discourages patients who tend to extend in their wheelchairs as a result of increases in tone. This 90° placement also leaves the pelvis free for anterior tilting, an assist for those patients who can use this mobility for added function (Fig. 32.21). Some patients can benefit from multiple angles of pull. For these clients, a four-point belt might be most appropriate. A four-point belt provides four places to anchor the belt. The top two anchors assist in pulling the pelvis back against the back support and the bottom two anchors assist in preventing the pelvis from shifting forward and up. Other pelvic positioners are available as discussed in Seating Principle 2: Achieve and Maintain Pelvic Alignment.
The pelvic belt should cross the pelvicfemoral junction at approximately a 45° to 60° angle to the seating surface.
A belt placed over the upper thigh (at a 90° angle to the sitting surface) will free the pelvis for natural anterior tilting.
Wheelchair armrests have many important functions. They provide a support surface for arms as well as a surface for pushing up to standing and a mechanism for ischial pressure relief (sitting pushups). The armrests are also used to support trays for UE support or communication devices. The height, length, and width of the armrests are important measurements to ensure independence and comfort. If the armrests are too high, undue stress can be placed on the shoulders and if too low, slumping to reach the support frequently occurs. If the armrests are too wide, it may interfere with lifting the armrest for transfers or affect the ability to propel the wheelchair. If too narrow, the arms may slip off rendering the armrests ineffective in assisting with trunk posture.
For some individuals, the armrests will be used to mount an upper extremity support surface (UESS) such as a tray or trough. These surfaces provide several important functions. They can be used to achieve symmetrical positioning of the UEs, maintain corrected alignment of the glenohumeral joint and scapula, and serve as a work or communication surface. They also can act as an adjunct to the postural control system by supporting the weight of the upper limbs and decreasing pull on the shoulders and trunk.
Style and position are important considerations when selecting foot support systems. Placement of the foot support system will directly affect the position of the entire lower body, affecting tone and posture in the trunk, head, and arms. Adequate hip flexion will help keep the pelvis well positioned on the sitting surface. Appropriate foot support height and style are required for maintenance of this position. Foot supports that are too low will result in lower knees, placing the hips in a more open angle and encouraging forward sliding of the pelvis. Foot supports that are too high may unload the thighs, placing increased weight on the ischial tuberosities. Elevating leg rests even in their lowered position may place excessive stretch on tight hamstrings, pulling the pelvis into a posterior tilt (Fig. 32.22). Any limitation of motion imposed by the hamstrings will directly influence the choice of foot positioners. To achieve maximum comfortable hip flexion, it may be necessary to flex the knees more than 90°, requiring special intervention on the foot supports. Decisions regarding straps and foot positioners must be made early, based on available ROM, to ensure caster (front wheel) clearance on the final unit.
Sitting alignment with the hamstrings on slack and the knees flexed (left) and positioning assumed with feet resting on elevating foot rests (right) causing tension on the hamstring that pulls the pelvis into a posterior tilt.
Secondary Support Surfaces
Other supports may be needed to improve trunk alignment, LE alignment, and head position. These supports are added to the main support surfaces and include, but are not limited to, lateral trunk supports, medial and lateral knee supports, lateral thigh supports, headrest, and anterior chest supports. When determining the need for these supports, a specific goal should be identified to justify each item.
The Wheeled Mobility Base
The wheeled base forms the mobility structure for the seating system. Mobility bases include manual systems and power systems. Manual systems can be set up for independent use where the user is able to propel the wheelchair or dependent use where a caregiver moves the chair.
Dependent manual systems include strollers, pushchairs, and some manual wheelchairs. These systems typically have small wheels that are not intended for self-propulsion. They may also be set up for increased ease of folding for transportation.
Four different methods of self-propulsion are available in the independent manual mobility category. Independent manual propulsion using both hands is indicated for those with good UE function and strength and is the most common. This system is usually set up with large rear wheels. However, the large wheels can be positioned in the center of the base (mainly used with children) or in the front of the base (Fig. 32.23). Positioning the wheels in different configurations can improve the ability to reach and propel the wheelchair. This is especially critical when considering the possible implications for long-term function of the shoulder girdle.
Wheelchairs with large front wheels and small rear casters may be easier for some patients to push, but are more difficult to use outdoors. Courtesy of Sunrise Medical, Carlsbad, CA 92008.
Research indicates that patients who use manual wheelchairs, especially if they are not properly fitted to their bodies and functional level, are in danger of UE damage from repetitive strain injuries (RSIs). Repetitive strain injuries can result in damage to soft tissue (tendons, ligaments, nerves) or bony structures secondary to frequent repeated motions such as wheelchair push strokes. The damage can include inflammation, compression, and/or tears in the shoulder joint and surrounding structures, resulting in pain and decreased function.28,29
Repetitive strain injuries have been identified in the shoulders, wrists, and hands of wheelchair users. Even patients without documented RSI report increased pain in these joints with prolonged wheelchair use.30,31 Small muscles are required to produce large forces repeatedly to move the chair through space. These same muscles are typically required for a variety of activities of daily living (ADL) tasks, thus increasing the demands placed on the same muscles with the potential of causing trauma. Muscles are used in atypical positions, and become overstretched and overused. Stress on the muscles and joints increases with increased wheelchair weight, increased user weight, and environmental factors. Many symptoms are not felt until the condition is well advanced. Rotator cuff injuries and instability of the glenohumeral joint are common at the shoulder. Since a number of muscles cross the wrist and elbow, problems occurring at the wrist often create pain at the elbow. Medial epicondylitis and carpal tunnel syndrome (CTS) are common. See Box 32.4 Evidence Summary for a summary of studies addressing UE pain associated with wheelchair propulsion.
Box 32.4 Evidence Summary Studies Addressing Pain Associated with Wheelchair Propulsion
|Reference ||Purpose ||Subjects/Design ||Results ||Conclusions/Comments |
|Sie et al28 (1992) ||To document the prevalence of UE pain according to specific UE regions, and the relationship of UE pain to time since injury in Ss with SCI. ||Nonrandomized cohort study; questionnaire sent to 239 Ss > 1 year post-SCI; mean age 37.4 years. Ss interviewed for presence of UE pain (shoulders, upper arms, elbows, lower arms, wrists, and hands), screened for CTS. ||55% of Ss with tetraplegia (quadriplegia) reported pain in at least one region of UE, 40% in more than one region. 64% of Ss with paraplegia reported UE pain, 32% in more than one region. 59% of all Ss reported some UE pain, 30% reported pain requiring medication, limiting function, or causing pain with ADL. Ss with paraplegia reported less significant pain than those with tetraplegia. 41% of all Ss reported shoulder pain. ||Shoulder region was the most common painful area in Ss with tetraplegia, and second most common in Ss with paraplegia. There was a general trend indicating that UE pain increased with time past since injury, up to 20 years. There was a steady increase in frequency of CTS-related complaints with time since injury up to 19 years, in Ss with paraplegia. |
|Fullerton et al (2003)a ||To compare the onset and prevalence of shoulder pain in the athletic and nonathletic W/C user populations. ||Cohort study; 20-item questionnaire, mailed to a randomized group of 500 individuals through the Virginia SCI Registry, 257 Ss were obtained, 86% had SCI. Patients were considered athletic if (1) trained at least 3 hours/week, (2) involved in at least 3 competitions per year, (3) had a W/C modified for sports. 172 of the Ss were identified as athletes. ||48% of all Ss reported shoulder pain, 70% of these Ss sought treatment for pain, and 92% had pain with ADL. 66% of nonathletes reported pain, only 39% of athletes reported pain. Pain and athletic status were not significantly related to onset of shoulder pain. There was no significant difference between Ss with tetraplegia and Ss with paraplegia. Age had a strong effect for both pain and athletic status. Nonathletic Ss were found to be more than twice as susceptible to shoulder pain as athletes independent of age, SCI level, and number of years in W/C. ||A limitation of this study is that one question remains unanswered: Do nonathletes have more pain because they are not athletic, or are they not athletic because of shoulder pain? There is a possibility of sampling bias because many of the questionnaires were hand-distributed. |
|Curtis et al (1999)b ||To compare the prevalence and intensity of shoulder pain experienced during daily functional activities in W/C users with tetraplegia and paraplegia. ||Nonrandomized cohort study; self-report survey; 55 women and 140 men; 92 Ss with tetraplegia (mean age 32.9 years) and 103 Ss with paraplegia (mean age 34.4 years). Ss used manual wheelchair for 3 hours per week and had at least 1 year since onset of SCI. Groups were partitioned according to age, level of daily activity, and years of W/C use. ||There was no significant difference between Ss with tetraplegia and with paraplegia in terms of age, years of wheelchair use, and weekly hours of activity. Ss with paraplegia performed more transfers per week and spent more hours per week using W/C (both significant). Less than 15% of all Ss experienced shoulder pain before becoming W/C users, 78% with tetraplegia and 59% with paraplegia had felt shoulder pain since they started using the W/C. There was significantly higher prevalence of previous, bilateral, and current shoulder pain in Ss with tetraplegia than those with paraplegia. Both groups had most severe shoulder pain when pushing the W/C up an incline, pushing for more than 10 minutes, and while sleeping. ||This study documents a strong influence of shoulder pain on the performance of functional activities after SCI. Ss with tetraplegia, increased age, and duration of W/C use were associated with avoiding strenuous functional activities. |
|Veeger et al (2002)c ||To examine the mechanical load on the glenohumeral joint and on the shoulder muscles during W/C propulsion at everyday intensities. ||Nonrandomized cohort study; three experienced male W/C users, ages 22, 27, and 38. Weight 180, 176, and 209 lb (81.5, 80, and 95 kg), respectively. All participated in W/C sports on a weekly basis. Each underwent four, 4-minute W/C exercise tests at two target resistances (10 and 20 N), and target speeds (0.83 and 1.39 m.s[-1]), during which data were collected for construction of a musculoskeletal model of the UE. Anthropometric parameters of the model based on data from two cadaver studies. Individual muscle performance estimates based on this model. ||Push time shortened significantly when velocity increased, while recovery time was reduced considerably with an increase power output. The muscle that produced the largest force during the push phase was the subscapularis. Supraspinatus and infraspinatus were also highly active. Pectoralis major produced a moderate internal rotational force. Biceps produced more force than triceps during push phase. During recovery phase, the scapular part of the deltoid produced more force than all other muscles. The supraspinatus was by far the most taxed muscle when force output is considered relative to maximal force. Also highly active were the forearms (pronators and the supinating effect of the biceps). ||Peak glenohumeral contact forces varied between 800 and 1400 N. The supraspinatus and infraspinatus may be responsible for an external rotation compensatory moment for the deltoid (excessive internal rotation may cause the greater tubercle to move directly under the acromion, thus increasing probability for impingement). Despite the relatively low contact forces, the peak forces and peak stresses in the rotator cuff muscles (particularly supraspinatus) appear high. These high peak stresses might cause overuse injuries. |
|Boninger et al (2001)d ||To investigate MRI and radiographic abnormalities in individuals with paraplegia who were W/C users. ||Nonrandomized cohort study; 28 Ss with paraplegia, 19 male and 9 female (mean age 35 yr), with a traumatic SCI at the 4th thoracic level or below, occurring more than 1 year before the start of the study. Ss used manual W/C full-time for mobility. Each subject completed a standardized questionnaire, had a uniform physical examination focusing on the shoulder, and underwent imaging studies (radiographic and MRI). BMI was calculated. ||5 Ss displayed osteolysis of the distal clavicle, 11 displayed subacromial spur, and 8 displayed AC DJD. Only nine Ss had radiographs that were read as entirely normal. One subject was found to have a rotator cuff tear. Distal clavicular edema was the most common abnormality found in MRI (20 subjects), 18 Ss displayed AC DJD, CA ligament problems were common as well. Ss with a high BMI had a greater degree of abnormality. ||It is hypothesized that shoulder injuries are due to the repetitive loading that occurs during transfers and W/C propulsion. BMI alone was not related to abnormalities, which may suggest that taller subjects who weigh more have musculoskeletal systems that are better able to handle increased stresses. |
|Samuelsson et al (2004)e ||To describe the consequences of shoulder pain on activity and participation in Ss with paraplegia who use a W/C, and describe the prevalence and type of shoulder pain. ||Nonrandomized cohort study; 56 potential Ss with paraplegia due to SCI (12 women, 44 men, mean age 49 years), more than 1 year before study were screened for participation via questionnaire; 21 (37.5%) of those responding had shoulder pain. 13 of these Ss were used to delineate the type and consequence of shoulder pain. The CMS, WUSPI, KBADLI, and COPM were used to describe the impact of shoulder pain on activity. ||The highest pain intensity was found for loading a wheelchair into a car, followed by pushing up inclines outdoors and usual ADL at work and school. 54% of Ss presented with problems related to self-care activities; 23% productivity; 23% leisure activities. The most common problem was transferring in and out of a car (62%) and W/C propulsion (46%). ||Sitting posture may be related to shoulder pain in this population. W/C users with SCI tend to adopt a kyphotic posture, which causes an abnormal rotation of the scapula. This could contribute to entrapment of the greater tubercle beneath the acromion. The most defined problems related to shoulder pain were associated with W/C use. |
When prescribing wheelchairs and features for patients who are able to self-propel, consideration must be given to preventing RSI whenever possible. An important prevention strategy is careful positioning of the UE to allow the most efficient stroke during propulsion, reducing the amount of force needed per stroke and reducing the number of strokes required to move the chair. It is also critical to observe wrist alignment and make any needed recommendations to minimize trauma and the chance of impingement leading to CTS.32,33,34 Other criteria that should be considered in prescribing a self-propelled wheelchair include selecting a chair that
Has the lightest weight possible
Has a stable frame for most efficient movement
Is well manufactured, with high-quality bearings (increased ease of motion for moving parts) for less roll resistance when push forces are applied, and secure nonmoving parts
Provides optimal wheel size and type consistent with patient size and function
Provides the best possible combination for ease of propulsion and stability
Many features must be considered when determining the optimal manual wheelchair setup for a person who is able to self-propel. Many bases are available, each with small differences that can increase or decrease the person's functional skills A rigid frame is lighter weight than a folding frame but may be more difficult to transport for some individuals. The ability to adjust the front and rear seat height by changing casters, fork lengths, and rear wheel size can assist a person with balance issues. The ability to change the seat back angle and the frame angle can assist a person with postural issues.
The second method of self-propulsion is using a one-arm drive system. This is appropriate for a person who is only able to functionally use one UE. In this case, there are two rims on the side being used to propel the wheelchair. The outer rim enables the chair to turn in one direction, the inner rim to turn in the other direction, and engaging both rims enables the chair to move forward (Fig. 32.24).
A double handrim on one side allows the user to drive a one-arm drive wheelchair with one hand. Courtesy of Sunrise Medical, Carlsbad, CA 92008.
The third method of self-propulsion is using one or both feet. When using this method, care should be taken to ensure that the seat is low enough to the floor so the person continues to have good positioning and does not risk sliding out of the wheelchair.
The final method that can be used for self-propulsion is a combination of one arm and one leg. In this case, care must be taken to have the seat low enough to the floor, as well as have the rear wheel an appropriate size and position to use for functional mobility.
A power mobility system (Fig. 32.25) consists of a base or frame, a seating system, and electronics (batteries, motors, control module, and driver control).
(A) Motorized wheelchairs offer patients with poor coordination, weakness, or paralysis an opportunity to move around in their environment. This chair is also equipped with a power-operated seating system. Courtesy of Sunrise Medical, Carlsbad, CA 92008. (B) Patient seated in a motorized chair; note that this chair includes a storage space for canes behind seat back. (C) Close-up of platform flip-up footrest.
If a person is unable to mobilize a manual wheelchair and is cognitively aware of surroundings, power mobility should be considered.35,36,37,38 It should also be considered for wheelchair riders who are marginal self-propellers in manual wheelchairs. They may be able to move around indoors, and on level surfaces outdoors, but cannot move around in the community environment without unduly stressing muscles and joints, creating postural problems, and/or imposing cardiovascular strain. Long-term overuse injury of muscles and joints and the possibility of skeletal deformity must be discussed with the patient and caregiver as part of the examination process. Patients must face the possibility that injury may create problems significant enough to impede function in critical areas such as transfers and ADL.28,29,30,31,32,33,34,39,40,41,42,43
An examination of the patient's full environment must be made to determine if power mobility will be helpful and usable (see Chapter 9, Examination of the Environment). Architectural barriers such as steps might preclude the use of power mobility or require that the patient have both a power and manual system for use at different times. In addition, attention should be given to how the chair will be transported, and the level of technology tolerance of both the consumer and caregiver. For patients whose condition is changing, a long-term plan must be established to guide decision making when choosing products. When considering power mobility for individuals who may have cognitive impairments, the rule of thumb is that the driver is aware of safety for himself or herself and others. In most cases, the ability to stop and to judge when to stop is more difficult to teach than driving itself. Awareness, reliable movement, motivation, and good response time are all important factors in wheelchair use.
A variety of control options are available for powered mobility, including hand control, head array systems, sip 'n' puff breath control system, single switch systems, and scanning array systems.
The most efficient method for driving a power wheelchair is with a hand. Joystick controls are used to control the direction and speed of the wheelchair. The final placement of the joystick is important to ensure that the person can reach the control without difficulty and without putting excessive stress on the wrist, elbow, or shoulder. Access to on/off switch, mode switch, and/or speed dial must be assessed to ensure independent control and prevent accidental hitting when driving.
Some individuals are unable to use their hand to mobilize the wheelchair but have good head control. A head array system can be used for driving. A simple system consists of three switches. The switch behind the head allows the chair to move forward, the one to the left side of the head turns the chair left, and the one to the right side of the head turns the chair to the right. Hitting a combination of the switches allows the user to maneuver the chair with increased ease. A fourth switch can be used for reverse or to toggle the system so the rear pad on the head array becomes reverse. This fourth switch can also be used to change the speeds and operate other wheelchair functions. Good head control is needed to operate this type of system.
Sip 'n' Puff System/Breath Control System
The sip 'n' puff system is used with breath control. A straw is used in the mouth. A hard puff allows the chair to move forward, a hard sip for reverse, a soft puff is right, and a soft sip is left. The air control is from the mouth rather than from the lungs. Systems can be calibrated for easier or harder puffs and sips. The system can be set up in latch mode (forward is locked after a hard puff) so the person is not required to constantly be puffing into the straw to keep the chair moving forward. Once in latch mode, small puffs or sips provide steer correction. A hard sip stops the chair. When using this type of system, it is important to have good lip closure without leakage through the mouth or nose for optimal efficiency. A combination of sip 'n' puff and switches can be used for driving a wheelchair if a person has difficulty differentiating the hard and soft puffs and sips.
A variety of single switches can be set up for driving a power wheelchair. If a person is unable to use a head array or sip 'n' puff system, single switches can be set up at any area with even minimal active movement (e.g., hand, elbow, head, chin, knee, foot, and so forth) to control the wheelchair. A tray can be used with good gross movement of the UE to activate a series of switches with each one assigned a different function. The switches can be different styles, sizes, and colors to differentiate function. Four switch placements are needed to operate a wheelchair using this method.
A scanning array is available for a person who only has one switch placement site available. A light scans around a display highlighting different directions. When the light hits the direction of travel, activation of the switch moves the chair in that direction. Once the contact is removed from the switch, the scanner light continues to move around the display in a preset fashion. Although this type of system can be slow and tedious, the ability to drive independently is extremely rewarding for the motivated person.
Foot, arm, and chin control systems are available for driving a power wheelchair. A variety of switch options are available that include proximity switches, zero touch switches, and infrared switches for driving a power wheelchair. Testing of the recommended equipment is essential to ensure that the person can drive safely and efficiently both indoors and outdoors.
Four types of power wheelchair bases are available for mobility, and each system has its own set of benefits. Every person is different and many people can only drive one type of power base. Testing is needed for both new users and experienced users who may want to change the type of chair they have been driving.
This style chair can be three or four wheeled and operates with a hand control lever system (see Chapter 9, Examination of the Environment). The seat options tend to be limited in sizes and supports. Many individuals like scooters for the ability to maneuver in small places, the ability to rotate the seat for transfers, and in some cases, the ability to elevate the seat for improved reach. These can be easier to disassemble for transport but might not have the power or electronic capabilities needed for driving outdoors. Although scooters tend to be less costly, consideration of a person's disability, changing needs, and environmental issues need to discussed before moving forward with purchasing a scooter.
A rear wheel drive wheelchair has the fixed drive wheels in the rear of the chair and the casters are in the front. Individuals driving this type of base see exactly where they are going and are able to watch their feet to ensure they do not hit walls, doors, or other items. Until recently, this was the most commonly used wheel drive base. With improved technology, center wheel drive bases are now the most commonly used base system.
A center wheel drive wheelchair has the fixed drive wheels in the center of the chair and small casters both in front and in the rear of the chair. The chair turns from the center and care must be taken when turning to know what is behind and in front of the chair. Better LE positioning can be attained owing to improved caster clearance.
A front wheel drive wheelchair has the fixed drive wheels in the front of the chair and the casters are in the rear.
When turning the chair, the back end moves first and care must be taken to ensure sufficient posterior clearance. This type of chair allows closer proximity to tables or sinks. Lower extremity positioning is improved with no caster clearance issues.
Adjustable Tilt-in-Space Seating Systems
Manual and power wheelchairs can have an adjustable tilt-in-space feature. The tilt-in-space feature is a seating system with a fixed seat to back support angle, fixed seat to lower leg support angle, and fixed lower leg to foot support angle that can be adjusted to tilt rearward or upright depending on the needs of the person (Fig. 32.26). In a manual wheelchair, in most cases, a caregiver needs to change the tilt position. In a power wheelchair, the person can independently adjust the seat tilt with switch access. The tilt feature is beneficial for individuals who have fair to poor trunk control and are unable to sit up straight against gravity for the full day. The tilt provides them with a resting and repositioning position. The tilt also assists with positioning a person in the wheelchair after transfers. The tilt feature can assist in improving balance and head positioning, improving skin integrity by assisting with shifting pressure from buttocks to back, and improving comfort.44,45
(A) Tilt-in-space wheelchairs tilt through space with their angles preset. (B) Patient performing pressure-relief maneuver in tilt-in-space chair. (C) Close-up of goal-post joystick.
Adjustable Recline System and Elevating Leg Rest System
Both manual and power wheelchairs can have an adjustable backrest system and an adjustable leg rest system. This allows the person to recline in the wheelchair. This can assist with pressure relief and pressure distribution, bowel and bladder care, orthostatic hypertension, comfort, and ROM.44 Each of these features can be ordered separately. On a manual wheelchair, a caregiver must adjust the recline and leg rest features. On a power wheelchair, the person can use power recline and power elevating leg rests independently with switch access. If manual elevating leg rests are obtained, the person will be dependent for leg positioning. Care must be taken when determining the need for both these features. In most cases, elevating the leg rests does not decrease edema; the legs need to be raised above the heart to achieve this effect. Hamstring muscle tightness needs to be examined to determine if appropriate sitting posture can be maintained with the legs elevated. Too often, extending the knees causes sliding of the pelvis on the seat surface. This increases the potential of pressure sores under the buttocks and promotes poor trunk posture. If increased muscle tone is present in the LEs, knee extension may cause spasms and pull the knee into flexion, often causing the leg to slip off the elevating leg rests and potentially causing injuries. The recline feature also needs to be examined carefully to ensure that the change in back position does not increase the potential for sliding down in the wheelchair.
A power seating system may include a power seat elevator feature. This feature allows the seat to be raised or lowered to accommodate for height differences and improve reach. This can improve access to tables, sinks, cabinets, and so forth. The feature can also increase ease for transfers on and off the toilet and bed. In the raised position, it can also provide improved social interaction. The power wheelchair can be driven using this feature, but the speed of the chair is slowed for safety concerns.
A stander is a device that allows a person to come to standing who ordinarily would be unable to stand without support. The stander can be a stand-alone device with or without wheels. For a person who would like to stand throughout the day without transferring to a different device, a stander is available in a manual wheelchair and a power wheelchair. In the manual wheelchair, the system is set up to raise and lower the person using his or her own arm strength. The added stander portion increases the weight of the chair but allows changing position throughout the day as needed to stand, stretch, reach, and work. In the power system, a switch is used to activate the stander and the same benefits achieved with a manual system can be achieved in the power system.
Power assist wheels are attached to a manual wheelchair. This provides the person with an assist on each propulsion.46,47,48,49 It increases the ease of pushing a manual wheelchair both indoors and outdoors. This can assist a person who prefers to use a manual wheelchair rather than shifting to a power wheelchair.
Specific Wheelchair Frame Features
Sling Back and Sling Seat Upholstery
Sling back and seat upholstery are standard items on basic manual wheelchairs. This is convenient when a person needs to fold the wheelchair for car transportation. However, sling upholstery can promote poor sitting posture, posterior pelvic tilt, hyperextended neck, and poor LE positioning. The sling upholstery should only be used when the chair is primarily being used for transportation, if the person will only be using it for short periods of time, if the person is able to reposition himself or herself and is not at risk for developing contractures, and if the system needs to be as light as possible for mobility. Sling back upholstery is a standard item on basic power wheelchairs. Caution should be used when recommending this type of back due to the potential for poor trunk posture, increased kyphosis, and increased hyperextended neck posture. If at all possible, sling upholstery should be avoided due to potential for development of poor posture and increased health problems. Firm back and seat supports can be added to the wheelchair and removed for transportation purposes. Figure 32.27 provides an overview of the foundational components of a prescriptive wheelchair.
Foundation components of a prescriptive wheelchair.
The back angle adjustment is available on some basic manual and power wheelchairs and most tilt-in-space seating systems. The back posts can be angled and bolted in a specific position. Depending on the wheelchair manufacturer and the wheelchair style, various amounts of back angle are available. Some chairs only have 10° of adjustment while others have 30° of adjustment. This feature is beneficial for a person with limited hip flexion, as well as a person who needs a fixed rearward tilt position who does not want a tilt-in-space seating system.
Seat Frame Angle and Height
The manufacturer of manual wheelchairs sets the seat frame angle and height. Some wheelchairs are available with adjustable axle plates and adjustable forks. This provides the ability to alter the wheel size, caster size, and wheel placement to achieve a specific height and specific frame angle (Fig. 32.28). This can help a person with hamstring tightness by improving clearance for feet or assist a person with difficulty sitting upright to be tilted rearward slightly for improved posture and UE control. This can also assist a person with reaching the floor for propulsion using the feet or improve the ease for performing transfers.
Lightweight rigid frame chair with adjustable suspension system, seat back angle, wheel base, and footrest lengths. The chair has knobby tires on spoked wheels. Courtesy of Sunrise Medical, Carlsbad, CA 92008.
The footrest system is made up of hangers, extensions, and footplates. The hangers mount to the wheelchair, and the extensions provide the appropriate length for the calf and footplate support. The hangers swing out of the way for transfers. If transferring independently, practice trials using the release mechanism will ensure patient skill and safety in their operation. The footplates can be fixed or adjustable. The adjustable footplates (footplate can be moved and, depending on placement and angle, affects the foot and knee position) allow optimal positioning of the foot when tightness is present at the knees (seat to lower leg support angle) or foot (lower leg to foot support angle). This provides increased flexibility for positioning, especially if a person has changing needs.
Armrests come in desk length or full-length styles. They can be fixed height or adjustable height. There are a variety of methods to move the armrests out of the way for access to tables and for transfers. The person's functional skills will determine what system is optimal for independence.
Rear wheel options on a manual wheelchair are important to ensure independent propulsion. If wheels are too large, excess strain can be put on the shoulders. If wheels are too small, they may be difficult to reach and propel. The type of wheel is important depending on the types of terrain the person will be using. Knobby tires may assist in rough terrain. A variety of wheel rims are available. Aluminum rims can be coated, have projections, or be a smaller size depending on method used for pushing.
Caster size options are numerous. A larger caster (8 in) may interfere with foot clearance depending on positioning needs. A smaller caster may provide improved positioning of feet and greater ease turning the wheelchair. Larger casters may improve ease of traveling over potholes or grates.
Options on a power wheelchair are more limited depending on the style of the wheelchair, but the tires tend to be wider for better traction. More options are available for casters on a rear wheel drive wheelchair and some prefer a larger front caster for improved driving on uneven terrain.
Manual and power wheelchairs come in a variety of widths and depths. If providing a person with a manual wheelchair, it is important to make sure the chair is not too wide or too narrow since this will affect the ability to propel the wheelchair (Figs. 32.29 and 32.30). Testing of the various chair widths is important to ensure that the shoulders are protected from excessive strain. The seat depth is important to ensure that optimal positioning can be achieved with seating supports.
A wheelchair that is too wide will make wheel access and propulsion more difficult for the patient.
A narrower wheelchair allows easier wheel access and propulsion.
Power wheelchairs and tilt-in-space seating systems may be available with adjustable seat widths and depths. This feature allows fine-tuning adjustments and attaining optimal sitting posture over time. Often, a range is provided for the adjustable seat width. Care should be taken to choose the most optimal range. For instance, if a width of 20 in (50.8 cm) is needed, a frame may be selected that can be adjusted from 16 to 20 in (40.6 to 50.8 cm) or 20 to 24 in (50.8 to 60.9 cm). If the patient is unlikely to gain weight, the smaller size should be chosen; if the potential for weight gain is evident, the larger size should be chosen. The newer power wheelchairs tend to have more seat depth adjustability, but again, care should be taken with the base length of the chair to make sure it will not be too long for maneuvering safely indoors.