An integral part of wheelchair seating

Detachable back systems replace the existing back and vary according to needs. There are three types: rigid, modular and combination. Back systems may be fitted to an active wheelchair, power wheelchair or posture wheelchair.

The main benefits of back support systems are to provide postural support and stability, improved balance (encouraging optimal positioning) whilst preventingand accommodating spinal deformities. Other benefits include better pressure distribution, increased comfort and increased sitting tolerance.

Back systems are most commonly prescribed for neuro-muscular conditions such as spinal cord injury, cerebral palsy, head injury and progressive neurological conditions. Back systems are prescribed where there is a high risk of postural deformity, for instance:

  • Progressive neuro-muscularconditions i.e. muscular dystrophy, multiple sclerosis, motor neurone disease etc.
  • Asymmetry of the trunk or pelvic musculature i.e. incomplete spinal cord injury or asymmetrical postures - primarily as a result of fluctuating or high tone.
  • Children with various neuro-muscular disabilities, especially during and after a period of rapid growth related to puberty.

A back system allows normal spinal curves to bemaintained by accommodating a person's thoracic kyphosis and stabilizing the pelvis at the level of the sacro-iliac joints (the level of the dimples) of the back. It is essential that the size, length, shape and style of the lateral supports be correct. The degree of recline depends on the amount of thoracic accommodation needed (the person's posture) and on their postural control.

A closer look at products - Rigid back systems

Rigidback systems are essentially shells that are custom prescribed according to client needs in terms of height, width, shape, depth of contouring, lateral support and degree of recline requirements.

The rigid backs discussed have numerous size configurations including height and width of back and style or shape of back, as well as a variety of "shell"depths. Lateral supports may be integral or removable / detachable.

Rigid backs are rigidly constructed, to offer good postural support and to allow for firm pelvic and spinal positioning. Various materials are used in the manufacture of the backs. Carbon fibre backs are very lightweight, mild steel and aluminium backs are heavier. The lighter back support systems are made from various composites, but are not necessarily more expensive.

Points to consider when selecting a rigid back:

The range of sizes and shapes (shoulder height, upper thoracic, mid thoracic andpelvic or tall, standard, short) available;

Depth of shell;

  • The type and shape of the laterals i.e. whether integral lateral support or lowerintegral pelvic supports; or additional detachable lateral supports (especially where there is a degree of asymmetry);
  • Degree of recline or angle to support the posture in the required alignment. Greater recline i.e. from 6 degrees up to 15 degrees is required for intermediate andadvanced seating;

Degree to which customization can be done to stabilize the pelvis;

Degree to which customization can accommodate or correct spinal scoliosis (with or without rib hump) and other postural deformities i.e. moulding into or building onto the foam back is possible on mostrigid backs.

As you can see - there are many variables to consider. It is strongly recommendthat you consult an experienced seating therapist or specialist whenconsidering a rigid back.

The prescription of a rigid back system should be part of a problem-solving process, in which your seating specialist applies the basic principles of seating and considers the ergonomics of the wheelchair in order to optimizeyour seating i.e. tilt-in-space; backrest to seat angle and the biomechanics needed to optimize your posture and function. When your seating specialist setsup your rigid back the same principles are followed.

Common mistakes made when prescribing and fitting rigid backs :

  • Rigid backs prescribed and ordered tendto be too tall (long);
  • Rigid backs fitted too high (no pelvicstabilization) or too low (if the back prescribed is too tall);
  • Often the service provider neglects to check that the total width of the user's body plus the thickness of the lateral supports does not exceed the width of the users current chair or chair to be prescribed;
  • Laterals not optimized for the individual; and
  • Cheaper backs often selected, which does not have minimum adjustment options to allow for normal biomechanical alignment.

Elsje Scheffler, Physiotherapist and Rehabilitation Consultant

Comparison of various rigid back systems and their features

The table below compares the most commonly available rigid backs, all of which allow for seat depthadjustment and have options to fit a headrest. Other backs such as the Recaro backs and other flat,upholstered backs with or without-laterals e.g. on the Kids Positionerwheelchair or the ROHO Retroback system are available in one size only with limited options for customisation. They are not contoured and offer little adjustment for accommodating the spinal curvatures, but they may offer comfort for certain users.

Modular Back Systems

Modularback systems have components which can be interchanged or adjusted and usually have highly adjustable laterals. Modular backs are not always a good choice for moderate scoliosis with rib hump and other prominent or deep deformities, as moulding is not always optimal.

Modularbacks include the Shonaquip Monty, Jay Modular and the Jay Focus Point back. In this table the features of the Shonaquip Monty and the Jay Focus point backs are listed.

Combination Backs

Combination backs have features of both rigid and strap-type back supports, usually with tension-adjustable straps and padded, adjustable lateral supports.

The clinical applications are:

to accommodate prominent or "deeper" scoliosis and kyphoscoliosis with prominent rib humps, thoracic kyphosis and other deformities.
to accommodate fixed deformities of the spine, where moulding in a rigid back orstandard buggy would not be sufficient.

An example of a combination back is the Shonaquip Gibby back. This is atension-adjustable back with padded adjustable lateral supports, available instandard sizes but often custom-made. Offers up to 15 degrees of backrest recline, which is required with more advanced seating i.e. accommodating a profound thoracic kyphosis or kyphoscoliosis.

I wish to thank the various suppliers for theirassistance with information and consent to use their photographs. I also wish to thank the clinicians who responded to the survey and who agreed to share their opinions and tips.

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