The effect of experimental low back pain on lumbar muscle activity in people with a history of clinical low back pain - a muscle functional MRI study.

J Neurophysiol. 2015 Dec 16;:jn.00192.2015

Authors: Danneels L, Cagnie B, D'hooge R, De Deene Y, Crombez G, Vanderstraeten G, Parlevliet T, Van Oosterwijck J

Abstract
In people with a history of low back pain (LBP), structural and functional alterations have been observed at several peripheral and central levels of the sensorimotor pathway. These existing alterations might interact with the way the sensorimotor system responds to pain. We examined this assumption by evaluating the lumbar motor responses to experimental nociceptive input of 15 participants during remission of unilateral recurrent LBP. Quantitative T2-images (muscle functional MRI) were taken bilaterally of multifidus, erector spinae and psoas at several segmental levels (L3 upper, L4 upper and lower endplate) and during several conditions: 1) at rest, 2) upon trunk-extension exercise without pain, and 3) upon trunk-extension exercise with experimental induced pain at the clinical pain-side (1.5ml intramuscular hypertonic saline injections in erector spinae). Following experimental pain induction, muscle activity levels similarly reduced for all 3 muscles, on both painful and non-painful sides, and at multiple segmental levels (p=0.038). Pain intensity and localization from experimental LBP were similar as during recalled clinical LBP episodes. In conclusion, unilateral and unisegmental experimental LBP exerts a generalized and widespread decrease in lumbar muscle activity during remission of recurrent LBP. This muscle response, is consistent with previous observed patterns in healthy people subjected to the same experimental pain paradigm. It is striking that similar inhibitory patterns in response to pain could be observed, despite the presence of pre-existing alterations in the lumbar musculature during remission of recurrent LBP. These results suggest that motor output can modify along the course of recurrent LBP.

PMID: 26683064 [PubMed - as supplied by publisher]