The natural course of spinal pain is heterogeneous but mainly characterised by ongoing or recurrent patterns. Although evidence reporting neuromuscular changes in people experiencing ongoing symptoms has been extensively investigated, adaptations in individuals with recurrent spinal pain have received less attention. This is the first systematic review that aimed to investigate whether changes in neuromuscular function are present in people experiencing recurrent spinal pain (neck and low back pain) during a period of remission.
A systematic review and data synthesis was conducted according to a published registered protocol (PROSPERO CRD42019141527). MEDLINE, EMBASE, CINAHL, ZETOC, grey literature sources, and key journals were searched from inception to September 2019. Observational studies investigating neuromuscular functions (muscle activity, spine kinematics, muscle properties, sensorimotor control, and neuromuscular performance) in people with recurrent spinal pain were included. Two independent reviewers completed eligibility screening, data extraction, and risk of bias assessment (Newcastle-Ottawa Scale). Data synthesis was conducted per outcome domain. Where clinical and statistically homogeneity existed, quantitative synthesis was performed. The overall strength of evidence was rated using the Grading of Recommendations, Assessment, Development and Evaluation guidelines (GRADE).
Results: 25 studies were included from 7464 identified records (n=489 participants with recurrent spinal pain). Only one study investigated people with recurrent neck pain (n=30). Overall, findings were supported by “very low” quality of evidence. Results from five studies assessing the recruitment of Transversus Abdominis (TrA) with ultrasound were synthesized quantitatively. No differences were found (P=0.33). However, the high statistical heterogeneity (I2 > 50%) was addressed with a sub-group analysis considering the training received before the assessment. People with recurrent low back pain and in the subgroup without pre-training showed an impaired recruitment of the TrA compared to healthy participants (P=0.001). Other findings regarding motor output identified greater co-contraction, redistribution of muscle activity, and impaired recruitment of deeper muscles in people with recurrent low back pain. Limited range of motion of the lumbar spine and greater perceived effort during an endurance task were identified as well. The paucity of evidence on other outcome domains (muscle properties, sensorimotor control, strength) didn’t allow us to draw meaningful conclusion and the literature investigating people with recurrent neck pain was extremely scarce.
Conclusion(s): Although the amount of evidence is limited and affected by a very low quality, findings support the existence of motor behaviour changes and limited range of motion in people with recurrent low back pain during a period of remission. However, these neuromuscular adaptations are heterogeneous across subjects but appear to have the common goal to provide protection of the painful region.
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No specific costs.
These findings highlight that new strategies triggered by pain (e.g. redistributed activity, co-activation) can remain after symptom resolution and lead potentially to negative long-term consequences, such as new painful episodes. Therefore, resolution of symptoms following treatment may not be sufficient, and motor control changes should be equally considered to ensure secondary prevention.
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No specific funding was received for this project.