7-10. Wheelchair Assessment, Design, Justification, and Managment

Objectives

• Identify proper wheelchair (WC) fit for a patient based on diagnosis & functional level.
• Demonstrate how to take WC measurements accurately.
• Prescribe an appropriate WC considering patient needs and available resources.
• Distinguish types of manual WCs, power‐mobility bases & controls, common accessories, and cushion technologies.
• Draft Letters of Medical Necessity (LMN) that fully justify every component of a WC order.
• Teach WC safety, car transfers, mobility techniques on varied surfaces, identification of architectural barriers, and basic maintenance.

Standard Manual Wheelchair Sizes (Factory Defaults)

• Adult: \text{Seat Depth }=16''\;|\;\text{Seat Width }=18''\;|\;\text{Seat Height }=20''
• Narrow Adult: 16''\times16''\times20''
• Slim Adult: 16''\times14''\times20''
• Tall Adult: 17''\times18''\times20''
• Hemi-height: variable depth/width, \text{Seat Height}\approx17.5''
• Problem: “Patients are not all standard sizes with standard problems!”—customization is the rule, not the exception.

Rationale & Process of Wheelchair Assessment

• Identify immediate physical & functional needs.
• Anticipate future needs (disease progression, anticipated recovery, growth, weight change, living situation, etc.).
• Select/justify WC & all components to meet both present and future demands.

Major Physical Factors That Affect Fit

1. Motor Function
   ‣ Strength, selective control, endurance, ability to perform pressure relief.

2. Neurological Status
   ‣ Sensation, tone/ spasticity, pathologic reflexes.

3. Postural Control
   ‣ Head, trunk, UE, LE alignment & stability.

4. Cardiorespiratory Status
   ‣ Aerobic endurance, supplemental O_2, ventilator mounts, LE edema.

5. Perception/Cognition
   ‣ Safety judgment, visual fields, memory, apraxia, neglect, body awareness, ability to follow commands.

6. Skin Integrity
   ‣ Open wounds, history/risk of breakdown, intact/altered sensation, motivation & technique for pressure relief, sitting tolerance.

7. Deformities / Anthropometry
   ‣ Contractures, skeletal asymmetries, bariatric body habitus, amputations, incontinence considerations.

Functional Needs

• Transfers
• Home/community accessibility (door widths, thresholds, carpeting, ramps, vehicle type, etc.)
• Previous long-term WC use (avoid drastic changes without trialing).
• Patient goals (desired vs necessary tasks—self-propulsion, sports, vocational demands).
• Transportation method (private car, van lift, public transit, airline travel).
• Funding source—who pays? (Medicare, Medicaid, private insurance, workers comp, self-pay, charity).

Prognosis‐Related Questions

• Will condition improve, deteriorate, fluctuate fast/slow? Device must meet widest expected spectrum.

Measurement & Documentation Tools

• Recommended forms (all downloadable from course Canvas):
‣ RIC Adult Seating Eval
‣ CSHCN Pediatric Seating Eval
‣ Medicaid WC Evaluation Form

Key Linear Measurements (CSHCN Numbering)

1. Top of head → buttocks

2. Top of shoulder → buttocks

3. Axilla → buttocks

4. Elbow (flexed 90^\circ) → buttocks

5. Posterior buttocks → popliteal fossa ("seat depth raw")

6. Foot length

7. Head width

8. Bi-acromial (shoulder) width

9. Axilla–axilla width

10. Hip (trochanter) width
    11–12. Bilateral popliteal → heel lengths (account for leg length discrepancies)

Translating Measurements → Chair Dimensions

Seat Depth

• Rule: \text{Finished Depth} = (\text{Buttocks→Popliteal}) -2\text{ to }3'' so calves are free & pressure is off popliteal fossa.
• Too long → posterior pelvic tilt / sacral sitting; too short → ↓thigh support & ↑pressure on ischial tuberosities.

Seat Width

• Rule: measure widest hips/ thighs in sitting; add \approx2'' (more only if orthotics/prosthetics/clothing layers needed).
• Too wide → poor UE reach on rims, scoliosis; too narrow → skin breakdown, abductor spasticity, shear.

Seat Height

• Standard \approx20''; Hemi \approx17–19'' (allows foot propulsion). Select for function: transfers, reach, foot-propel.

Back Height

• Measure seat surface → inferior angle of scapula; subtract/ add per posture goals & cushion thickness.
‣ Low back (sports chairs) promotes UE mobility/trunk function.
‣ High back required for poor trunk control, power tilt/recline.

Seat-to-Footplate (Footrest) Length

• Measure heel → posterior thigh; subtract cushion thickness; leaves \geq2'' ground clearance.
• Error → edema, nerve compression, decreased stability.

Armrest Height

• Measure elbow in 90^\circ flexion → seat + cushion; add \approx1'' if additional support desired.
• Improper height = shoulder elevation or trunk lean.

Manual Wheelchair Frames

Folding vs Fixed

• Folding: easier transport & storage, heavier, more joints = more failure points.
• Fixed (rigid): lighter, stiffer ride, more efficient propulsion, harder to fit into cars.

Weight Categories & Typical Users

• Companion / travel chair: small rear wheels, caregiver propelled.
• Standard weight (35–50\text{ lb}): durable, low cost, limited adjustability (aka “Wal-Mart loaners”).
• Lightweight (<35\text{ lb}): adjustable axles, more leg rest options.
• Ultra-lightweight (\le13\text{ lb}): highly customizable, price premium, primary mobility users.

Specialty Manual Frames

• Hemi-height: adjustable axle height, 17–19'' seat; not only for CVA—good for any foot-propeller.
• Amputee: axle moved posteriorly to redistribute \Delta COM, often has anti-tippers.
• Reclining: hydraulic back recline; prevents syncope, manages hypotension, but watch shearing.
• Tilt-in-space: seat + back tilt as one unit; superior pressure relief, maintains hip angle, ↓shear.
• Bariatric: reinforced frame, wider seat, higher weight capacity—trade-off = heavier, fewer accessories.

Wheel Components

• Large Wheels: standard spokes (lighter, require truing) vs. mag (maintenance-free, heavier).
• Tires: solid (flat-free, harsh) vs pneumatic (smooth, needs air) vs solid inserts.
• Push rims: bare metal/plastic, vinyl coat, "Quad knobs", roller-blade style.
• Wheel locks: anterior push-to-lock vs posterior pull; scissor locks tuck under seat; add extensions for one-hand users.

Seating & Support Components

Armrests

• Configurations: full-length vs desk-length; fixed, removable, swing-away; height-adjustable for weak trunk.
• Trade-offs: fixed aids sliding-board transfers but blocks under-table clearance.

Leg & Foot Supports

• Footrests: support feet only; optional heel loops.
• Legrests (ELRs): support foot + calf; usually swing-away, removable, padded; elevate for edema or orthopedic precautions.

Anti-tippers & Stabilizers

• Attached to frame to prevent tipping—standard on tilt/recline; vital for amputees.

Lateral Supports, Trays, Troughs

• Provide trunk or UE alignment, mount on armrest receivers, often custom.

Power Wheelchair Mobility Bases

• Front-wheel drive: open front, moderate turning radius, stable on inclines.
• Mid-wheel drive: tightest turning radius, high maneuverability indoors, poor on uneven terrain.
• Rear-wheel drive: widest turning radius, best traction outdoors, may tip backward on steep ramps.

Control Interfaces

• Joysticks (standard & mini), sip-and-puff, head array, chin, foot, switch arrays; vendor can customize.
• Emerging options: scooters, all-terrain chairs, standing chairs, iBOT gyroscopic base, power-assist add-ons.

Cushions & Pressure Management

Purpose
• Redistribute pressure, maintain posture, aid balance, adjust seat height, permit prolonged sitting.

Types & Pros/Cons
• Foam: inexpensive, customizable contours, poor for wound management.
• Gel: heavier, moves with pt, good pressure distribution if high-end (e.g., Jay); can hinder sliding transfers.
• Air: excellent micro-pressure relief (Roho), lightweight; high maintenance (air pressure checks), unstable for tone.
• Honeycomb (Supracor Stimulite): breathable, washable, moderate pressure relief, patient-preferred for comfort.
• Hybrid (Jay Fusion, Roho Hybrid Elite): combine foam + gel or foam + air—balance stability and pressure relief.

Safety Restraints & Positioning Belts

• Velcro, automotive‐style latches, alarms.
• Purposes: safety, tone management, posture during transport.

Wheelchair Prescription Workflow (Clinic Algorithm)

1. Decide propulsion: manual vs power.

2. MANUAL pathway
   ‣ Select frame (standard/light/ultra/specialty), wheel/tire/caster type, locks, arm/leg rest style, cushion, accessories.

3. POWER pathway
   ‣ Choose mobility base, control interface, arm/leg rest style, cushion, accessories.

4. Justify each choice relative to physical & functional findings, prognosis, payor requirements.

Letter of Medical Necessity (LMN) – 11-Point Checklist

1. Confirm item is benefit-eligible.

2. Quote insurer’s definition of “medical necessity.”

3. Audience-appropriate language; avoid jargon.

4. Identify author & credentials.

5. Describe patient diagnosis, deficits, prognosis.

6. Provide detailed equipment description (model #, options).

7. Argue cost-effectiveness vs alternatives.

8. Medical necessity of EACH component (seat width, cushion, anti-tippers, etc.).

9. Personalize impact—how equipment changes daily life. ‣ Rule 9A: “Add guilt”—pre-thank insurer for supporting independence.

10. Attach written prescription.

11. Include photos/brochures for clarity.

Wheelchair Safety & Transfers

• ALWAYS lock wheels before transfers.
• Remove/swing footrests; secure armrests.
• Use seat belt when needed.
• Car transfers: position chair, transfer occupant, fold & load WC (link to demonstration video provided in class).
• Environmental variables: car height, door width, pt. & caregiver strength/flexibility, WC dimensions.

Mobility Techniques & Architectural Barriers

• Propulsion strategies: bilateral UE, unilateral UE/LE (hemi), foot propulsion.
• Skill practice: wheelies, curbs, ramps, uneven surfaces (gravel, grass, carpet), doorways, stairs (emergency only, with 2 helpers).
• Alternative solutions: home elevators, ramps.

Wheelchair Maintenance (Monthly Unless Otherwise Indicated)

• Tighten bolts/nuts.
• Lubricate moving joints & wheel bearings.
• Clean frame, wheels, cushions, upholstery.
• Inspect pneumatic tire pressure & tread.
• Adjust & test wheel locks.

Ethical & Practical Implications

• Over- or under-prescribing leads to injury, social isolation, and wasted healthcare dollars.
• Proper WC fit = enhanced independence, pressure injury prevention, cardiovascular health, psychosocial participation.
• Clinician must balance patient desires, functional realities, prognosis, and funding constraints while advocating ethically.

Key Numerical Rules of Thumb (Quick Reference)

• \text{Seat Depth}=\text{Buttocks→Popliteal}-2{\text{ to }}3''
• \text{Seat Width}=\text{Hip Width}+2'' (≥ if orthotics)
• \text{Seat Height}_{\text{std}}\approx20''; \text{Hemi}\approx17–19''
• \text{Back Height}=\text{Seat}\to\text{Inferior Scapula Angle} (± for cushion & stability)
• \text{Footrest Clearance}\ge2'' off ground after cushion calibrated.