Pain provocation following sagittal plane repeated movements in people with chronic low back pain: Associations with pain sensitivity and psychological profiles
Authors: Rabey Martin , Smith Anne , Beales Darren , Slater Helen , O’Sullivan Peter 
Published: March 2017

Abstract

Background and aims
Provocative pain responses following standardised protocols of repeated sagittal plane spinal bending have not been reported in people with chronic low back pain (CLBP). Potential differing pain responses to movement likely reflect complex sensorimotor interactions influenced by physical, psychological and neurophysiological factors. To date, it is unknown whether provocative pain responses following repeated bending are associated with different pain sensitivity and psychological profiles. Therefore the first aim of this study was to determine whether data-driven subgroups with different, clinically-important pain responses following repeated movement exist in a large CLBP cohort, specifically using a standardised protocol of repeated sagittal plane spinal bending. The second aim was to determine if the resultant pain responses following repeated movement were associated with pain and disability, pain sensitivity and psychological factors.

Methods
Clinically-important (≥2-points, 11-point numeric rating scale) changes in pain intensity following repeated forward/backward bending were examined. Participants with different provocative pain responses to forward and backward bending were profiled on age, sex, pain sensitivity, psychological variables, pain characteristics and disability.

Results
Three groups with differing provocative pain responses following repeated movements were derived: (i) no clinically-important increased pain in either direction (n = 144, 49.0%), (ii) increased pain with repeated bending in one direction only (unidirectional, n = 112, 38.1%), (iii) increased pain with repeated bending in both directions (bidirectional, n = 38, 12.9%). After adjusting for psychological profile, age and sex, for the group with bidirectional pain provocation responses following repeated spinal bending, higher pressure and thermal pain sensitivity were demonstrated, while for the group with no increase in pain, better cognitive and affective psychological questionnaire scores were evident. However, these associations between provocative pain responses following movement and pain sensitivity and psychological profiles were weak.

Conclusions
Provocative pain responses following repeated movements in people with CLBP appear heterogeneous, and are weakly associated with pain sensitivity and psychological profiles.

Implications
To date, suboptimal outcomes in studies examining exercise interventions targeting directional, movement-based subgroups in people with CLBP may reflect limited consideration of broader multidimensional clinical profiles associated with LBP.
This article describes heterogeneous provocative pain responses following repeated spinal bending, and their associated pain sensitivity and psychological profiles, in people with CLBP. These findings may help facilitate targeted management.
For people with no increase in pain, the lack of pain provocation following repeated spinal bending, in combination with a favourable psychological profile, suggests this subgroup may have fewer barriers to functional rehabilitation. In contrast, those with pain provoked by both forward and backward bending may require specific interventions targeting increased pain sensitivity and negative psychological cognitions and affect, as these may be may be important barriers to functional rehabilitation.