Persons with recurrent low back pain exhibit a rigid postural control strategy

Abstract

Persons with recurrent low back pain (LBP) have been observed to have altered proprioceptive postural control. These patients seem to adopt a body and trunk stiffening strategy and rely more on ankle proprioception to control their posture during quiet upright standing. The aim of this study is to determine the effect of changing postural condition (stable and unstable support surface) on postural stability and proprioceptive postural control strategy in persons with recurrent LBP. Postural sway characteristics of 21 persons with recurrent LBP and 24 healthy individuals were evaluated in upright posture with or without standing on "foam" for the conditions as follows: (1) control (no vibration); (2) vibration of the triceps surae muscles; (3) paraspinal muscle vibration; (4) vibration of the tibialis anterior muscles. Vision was occluded in all conditions except for one control trial. All trials lasted 60 s. Vibration (60 Hz, 0.5 mm), as a potent stimulus for muscle spindles, was initiated 15 s after the start of the trial for a duration of 15 s. Persons with recurrent LBP showed significantly different postural control strategies favoring ankle muscle proprioceptive control (ratio closer to 1) instead of paraspinal muscle proprioceptive control (ratio closer to 0) for both standing without foam (ratio ankle muscle/paraspinal muscle control = 0.83) (P < 0.0001) and on foam (ratio ankle muscle/paraspinal muscle control = 0.87; P < 0.0001) compared to healthy individuals (0.67 and 0.46, respectively). It is concluded that young persons with recurrent LBP seem to use the same proprioceptive postural control strategy even in conditions when this ankle strategy is not the most appropriate such as standing on an unstable support surface. The adopted proprioceptive postural control strategy might be effective in simple conditions, however, when used in all postural conditions this could be a mechanism to undue spinal loading, pain and recurrences.

A kinematic analysis of relative stability of the lower extremities between subjects with and without chronic low back pain

“…Although the knowledge surrounding proprioception is relatively limited because it is such a complex function, several studies have found that proprioceptive deficits in individuals with LBP might contribute to a lack of stability [8,33,34]. Another explanation for decreased balance performance in LBP subjects might be altered muscle function.…”

Proprioceptive use and sit-to-stand-to-sit after lumbar microdiscectomy: The effect of surgical approach and early physiotherapy

“…1): transmuscular surgery + physiotherapy (n = 6), transmuscular surgery + usual care (n = 6), paramedian surgery + physiotherapy (n = 6), and paramedian surgery + usual care (n = 7). These groups were clustered by a mixed group design because power analysis (Brumagne et al, 2008;Claeys et al, 2011Claeys et al, , 2012Claeys et al, , 2015Janssens et al, 2015) revealed a sample size of 11 participants to provide adequate power (0.80 with a two-tailed alpha level of 0.05) to detect a clinically relevant difference in center of pressure displacement on unstable support surface (our primary outcome measure with smallest effect size). First, they were randomly allocated (blinded by computer algorithm) for surgical approach into a transmuscular group (n = 12; 7 women/5 men) and paramedian group (n = 13; 7 women/6 men).…”

“…The amount of this center of pressure displacement represents the extent to which an individual makes use of the proprioceptive signals of the vibrated muscles to maintain the upright posture. Muscle vibrators (Maxon motors, Switzerland) were applied bilaterally over the triceps surae ('ankle') muscles and lumbar paraspinal ('back') muscles, as studied previously (Brumagne et al, 2008;Claeys et al, 2011Claeys et al, , 2012Claeys et al, , 2015Janssens et al, 2015). Participants were instructed to stand barefoot on the force plate, with their arms relaxed along the body and occluded vision.…”

“…'Abs ankle' is the absolute value of the mean center of pressure displacement during ankle muscle vibration and 'Abs back' during back muscle vibration. An RPW score equal to 1 corresponds to 100% reliance on ankle muscle proprioception, whereas a score equal to 0 corresponds to 100% reliance on back muscle proprioception (Brumagne et al, 2008;Claeys et al, 2011Claeys et al, , 2012Claeys et al, , 2015Janssens et al, 2015).…”

“…A possible mechanism for this is reduced lumbosacral proprioception. When lumbosacral proprioceptive signals lose reliability due to LBP, individuals are likely to rely dominantly on ankle proprioceptive signals, irrespective of the postural demands (Brumagne et al, 2008;Claeys et al, 2011Claeys et al, , 2015. Consensus on the effect of lumbar surgery on postural control is lacking.…”