This is the fourth slide lecture in a series of eight lectures thatare intended to provide an overview of the wheelchair mobilityand seating evaluation process. The lecture series contains:

•Seating Biomechanics

•Wheelchair Seat Cushions

•Pressure Mapping

•Wheelchair Backs

•Manual Wheelchair Propulsion Biomechanics

•Rehabilitation Technology Suppliers & Clinicians

•Service Delivery

•Strategies for Effective Documentation

Wheelchair Back Supports

Mark R. Schmeler, MS, OTR/L, ATPMary Ellen Buning, MS, OTR, ATP

Center for Assistive Technology, UPMC Health SystemDepartment of Rehabilitation Science & Technology

University of Pittsburgh

1

Schmeler, MR & Buning, MEOctober 1999

Abstract and Presenter Bio-sketch

• Mark Schmeler is the Director of ClinicalServices at the Center for Assistive Technology.He has many years of front-line clinicalexperience in seating and mobility withindividuals with complex seating needs.

• Mary Ellen Buning is a research associate in theRehabilitation Science and TechnologyDepartment with interest in AT education,service delivery and functional outcomes thatresult from AT devices and services.

Schmeler, MR & Buning, MEOctober 1999

Presentation Outline

• This lecture will cover:– The spine and trunk– Spinal deformities– Types of back supports &

their characteristics

The back support in a wheelchair can have a significant effecton a number of different things. Think of the spine as a stackof blocks that needs some external support. Sitting is thehuman posture that is least helpful to good back mobility andmaintenance of functional flexibility.

There is always some risk for deformity especially when thereare any neurological or orthopedic problems

Think holistically… or with “systems” type thinking. If thetrunk needs support then cushions that support the pelvisneed to be considered along with support of the trunk.

Schmeler, MR & Buning, MEOctober 1999

Spine & Trunk

• Stack of blocks• Primary and secondary

curves• Mobility of the spine

The primary curves are more mobile. These are the curves atthe neck and the lumbar (lower back) spine. These curves arewhere the spine gets the greatest mobility.

Schmeler, MR & Buning, MEOctober 1999

Spinal Deformities

• kyphosis• scoliosis• lordosis• kyphoscoliosis

Khyphosis occurs when there is an exaggeration of the curvesof the thoracic (chest) and cervical (neck) spines

Lordosis occurs when there is an exaggeration of the curve atthe lumbar spine.

Scoliosis occurs when there is an atypical lateral or sidewayscurve introduced to the spine. Instead of arising straight fromthe pelvis, the spines cures laterally. These lateral changesare usually related to greater tone on one side of the body orthe trunk than the other.

Kyphoscoliosis is also known as rotoscoliosis. This deformityoccurs when kyphosis combines with a scoliosis to create adeformity in 2 planes.

Schmeler, MR & Buning, MEOctober 1999

Severe Kyphoscoliosis

Kyphoscoliosis is a combination of deformity in both lateraland anterior/posterior planes.

This person is sitting on the edge of a mat. The pelvis is tippedsharply backward. The spine is curving laterally out to thisperson’s left and the right shoulder blade is forward of the leftone.

Schmeler, MR & Buning, MEOctober 1999

Severe Lordosis

This person is sitting on the edge of a mat. The pelvis is tippedsharply forward. A deep curve in the lumbar spine is creatinga deep crease in the lower back. The fold in the skin willcontribute to heat and moisture problems.

This is an example of lordosis that could have been bettermanaged with the right cushion and pelvic positioning.

Schmeler, MR & Buning, MEOctober 1999

Characteristics of Back Supports

• Seat back vary by:– height– shape– stiffness

These 3 variables in back supports are the most basiccharacteristics. Not a lot of science has gone into backsupports until just recently.

Schmeler, MR & Buning, MEOctober 1999

Low Back

• Allows forsupport in lumbarregion

• Preferred byactive users

• User needs goodtrunk strength forlong termsuccess.

A low back on a wheelchair allows increased mobility in thespine i.e., rotation of the upper spine paired with good supportin the lumbar region.

This kind of back offers less stability (easier rearward tipping)and less support for the upper spine

Most active wheelchair users would not trade their increasedmobility for increased stability.

Schmeler, MR & Buning, MEOctober 1999

High Back

• Providesadditionalsupportthroughout spine

• Trade off =limited orreduced mobility

Back supports on a typical wheelchair are too high and theyare not adjustable. This hinders use of the arms and upperbody for mobility. In this case ability to push wheelchair islimited.

Stability is important for users with higher level injuries but allflexibility and mobility is lost. Choosing the right heightthrough customization or proper measurement gives themaximum amounts of stability with no loss of mobility.

Schmeler, MR & Buning, MEOctober 1999

Flat Back

• Does notaccommodateshape of thespine

• Does allow forsome mobility

If the seating goal is to give a client increased freedom ofmovement then this type of back is good. Lateral pads can beattached to this type of back which can be helpful for a clientwho needs extra support.

This type of wheelchair back is often used for children’swheelchairs.

Schmeler, MR & Buning, MEOctober 1999

Generically Contoured Back

• Accommodatesshape of the back

• Effectiveness issensitive to fit

• Deeper contourprovides greaterlateral support.

This type of back gives additional lateral support but helps theuser retain the ability to move within its supporting shape.

Lumbar support is not built into these kinds of backs.Permanent lumbar support turns out not to be that much of apart of adult seating. Most adults sit with a flat back. Having alumbar roll feels good at first but becomes painful. Therefore,it is good to have it adjustable.

It is an asset when you can add it or take it away such as ispossible with an an air bladder. Automotive seating is nowexperimenting with this type of adjustability in car seats.

Schmeler, MR & Buning, MEOctober 1999

Rigid Shell Back

• Provides goodstability

• Generally notadjustable

• Effectiveness issensitive to fit

The shape of a rigid shell back is NOT going to match theshape of the individual’s spine. The assumption is made withthis wheelchair back that the individual has a straight spine,i.e., no scoliosis.

People with spinal abnormality should not be placed in thiskind of back. A rigid shell back will force the torso posture offin another abnormal direction.

Schmeler, MR & Buning, MEOctober 1999

Soft Contouring

• Less stable• Contours to

shape of spine• Adjustable• Effective if

adjustedproperly

This type of seating is very useful in working with fixeddeformities. It can be used to accommodate kyphosis orposterior pelvic tilt.

This wheelchair technology is adjustable and recyclable so itcan be very useful in a long-term care facility. In this type offacility a fleet of wheelchairs should be able to adaptable forthe seating needs of many different kinds of seating needs forthe changing residents of the facility. However, staff needclinical expertise since it is important for the wheelchair backto be set up correctly for each client.

Schmeler, MR & Buning, MEOctober 1999

Custom Contoured

• Very specific to aparticular deformity

• Labor intensive• Dependent on skill

of fitter• Dependent on

accuracy oftechnology

The drawback of custom contour seating is that it takes a lotof time to fabricate and finish. The quality of the end productdepends on a clinicians skill in molding and shaping the back.

When working with clients with severe disability the shape ofthe spine can be accommodated while also giving pressurerelief.

New contour seating companies offer a means to create themwith CAD-CAM (computer aided design/computer aidedmanufacturing) so that the turn around is very quick.

This type of seat back don’t work with TSLO or body jackets.For clients with these external orthotics it is better to use aflat-type back and let the orthotic do its job.

Schmeler, MR & Buning, MEOctober 1999

Otto Bock Adjustable back

• Gives more involved usersadditional trunk support.

• Variable contour createdby using different cellvolumes.

• Heat moldable plasticlaterals can be modified toincrease support.

Schmeler, MR & Buning, MEOctober 1999

Scapular Cut Outs

• Provides the supportof high back with cutouts at the scapula.–Allows for increased

shoulder ROM–Aids propulsion as

well as ADLs.

Some clients need alternatives to standard wheelchair backs.Adjustability at the scapula (shoulder blades) allows maximumsupport with increased range of motion (ROM) for upperextremities.

Schmeler, MR & Buning, MEOctober 1999

Review Questions

• What does a wheelchair back contributeto comfort and function when seated ina wheelchair?

• When do you accommodate or adapt awheelchair back for a spinal deformity?

• Versus… when do you correct a spinaldeformity?

Schmeler, MR & Buning, MEOctober 1999

Recommended Reading

• Products and Services section of WheelchairNetat:http://www.wheelchairnet.org/ProdServ/Products/cushion.html

• RehabCentral- a WWW resource for clinicians onseating and mobility issues at:http://www.rehabcentral.com/

• Proceedings of the International SeatingSymposium & the RESNA Conference at:http://www.wheelchairnet.org/WCU/Departments/biblio.html