Non-deformity Spinal Bracing: What is the evidence?

The topic of non-deformity spinal bracing, or back supports is controversial. While there are clinicians who insist that the use of a back support or brace results in "weakening of the muscles" or creating a "dependency" on an external support, other clinicians recognize that placing a support on patients often helps them return to full function sooner and avoid the well-documented harmful effects of prolonged immobilization and inactivity. Although there is no hard scientific evidence of the clinical effectiveness of back supports and braces as a group, retrospective studies have documented improvements in symptoms in 30-80% of patients suffering with low back pain.

Spinal braces or supports are classified into one of three distinct categories - corrective, supportive, or immobilizing. Corrective braces are used in the treatment of disorders such as idiopathic scoliosis and kyphosis and will not be discussed in this report. A review of the effects, myths, and indication for spinal braces that provide both support and immobilization is presented.

Effects of Back Supports on the Lumbar Spine

  • Lumbar SpineBack Supports Physically Restrict Motion or Movement
    The effect of spinal bracing on the movement of the spine has been studied extensively. Norton and Brown showed that lumbar flexion/extension was reduced, but not eliminated. In many cases, motion of the spine was increased towards the upper and lower margins of the braces tested. Wasserman and McNamee contended that fixation of the pelvis was essential to achieving restricted lumbar motion. Attempts, however, to immobilize the pelvis in order to restrict lumbar motion have been shown to be impractical. Therefore, while movement restriction in the thoracolumbar region may be achieved to some degree, external motion limitation in the lumbosacral region may not be possible.
     
  • Back Supports Physically Restrict Motion or Movement
    The effect of spinal bracing on the movement of the spine has been studied extensively. Norton and Brown showed that lumbar flexion/extension was reduced, but not eliminated. In many cases, motion of the spine was increased towards the upper and lower margins of the braces tested. Wasserman and McNamee contended that fixation of the pelvis was essential to achieving restricted lumbar motion. Attempts, however, to immobilize the pelvis in order to restrict lumbar motion have been shown to be impractical. Therefore, while movement restriction in the thoracolumbar region may be achieved to some degree, external motion limitation in the lumbosacral region may not be possible.
     
  • Back Supports Help the Wearer Achieve Proper Posture
    One of the greatest benefits of a properly designed back support is the proprioceptive feedback that the support provides. When one is wearing a back support there is an increased awareness of the position of the pelvis and lumbar spine. This constantly reminds individuals of their body positions, making it easier to avoid undesirable postures.
     
  • Back Supports Increase Intra-Abdominal Pressure to Decrease the Weight-Bearing Load on the Spine
    Morris, Lucas and Bresler showed generalized contraction of the trunk muscles, including the intercostals, the abdominals, and the diaphragm occurs when lifting heavy weights. The upward push on the diaphragm caused by increased intra-abdominal pressure reduced the force on the spine. The study indicated that a back support raised intra-abdominal pressure while sitting and standing by 25%, but showed that abdominal muscles didn't work as hard when a subject was wearing a back support during heavy lifting. This study suggests that the greatest benefit of a back support might be derived from the relatively constant unloading of the spine during normal activities, rather than during heavy lifting. Nachemson and Morris studied the effects of a back support on intradiscal pressure and concluded that there was a 15-28% decrease in the total load on the disc studied. In another study, Nachemson, Schultz, and Anderson found inconsistent changes in spinal loading in patients wearing a lumbar brace. They did find that lumbar compression forces were reduced by about 1/3 in a task involving trunk flexion. The implication is that while a support may effectively unload the spine during certain activities, the same unloading effect can be naturally achieved through the proper contraction of the abdominal musculature. Since almost all back disorders are the result of cumulative trauma from prolonged sitting or standing, one would conclude that this unloading is of great benefit. Even when individuals are active, they will not be contracting the abdominal muscles constantly. Therefore, a back support can assist the abdominal muscles in their supportive function.
     
  • Back Supports Stabilize the Pelvis and Lower Spine
    By increasing the intra-abdominal pressure, a back support acts much like the stays and support rings of a barrel. If the support rings are tightened and/or strengthened, a stabilizing effect is achieved. When one tightens or contracts the abdominal, trunk, and pelvic muscles, the spine is stabilized. A properly designed lumbar support, capable of increasing intra-abdominal pressure, acts the same way.
Updated on: 03/22/16
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Back Support Myths and Indications for Spinal Bracing
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Back Support Myths and Indications for Spinal Bracing

Learn about back support myths and indications for spinal bracing.
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