Disuse and physical deconditioning in the first year after the onset of back pain

Bone health and back pain: what do we know and where should we go?

Bone health is generally not considered in patients who present with chronic back pain. Nonetheless, bone health and back pain share common genetic and environmental correlates suggesting a co-dependence. Evidence exists for a relationship between back pain and impaired bone health. Here we present the evidence, theoretic framework and clinical relevance. Bone health and back pain are important determinants of musculoskeletal health. Back pain experienced in youth is a risk factor for future back pain, while suboptimal bone health during development increases the risk of skeletal fragility in later life. Generally, bone health is not considered in patients with chronic back pain who do not demonstrate other well-recognised bone health risk factors or associated conditions. Nonetheless, evidence suggests that back pain and impaired bone health share common environmental and genetic correlates, indicating that bone health ought to be considered in the context of back pain in otherwise healthy individuals. This review describes the likely mechanisms explaining the relationship between back pain and impaired bone health, evidence concerning the relationship and suggestions for future research. A narrative literature search was conducted using CINAHL, Medline, PubMed and Web of Science electronic databases. A history of back pain is associated with decreased bone mineral density in adults, yet this tends to be site-specific. No studies were identified examining this association in youth, yet the negative effects of childhood skeletal trauma and obesity on bone and spinal health provide indirect evidence for an association. Further research is required to clarify the impact of back pain on bone health at different lifespan stages using prospective cohort designs.

The disabling role of fluctuations in physical activity in patients with chronic low back pain

Patients with chronic low back pain (CLBP) often report a disabling decrease in their activity level due to pain. The nature of the association between disability, activity, and pain over time is however, unclear. An intriguing issue here is whether a high level of pain-related disability is associated with a low activity level or are changes in the level of activity over time pain provoking and thus more disabling? The objectives of this study were to investigate associations between disability, pain intensity, pain-related fear, and characteristics of physical activity in patients with CLBP. A total of 42 patients with CLBP were recruited from the Pain Clinic of the Maastricht University Hospital. Each pain patient carried an electronic diary for one week, in which questions about current pain intensity, and the level of physical activity were completed at 8 moments a day. Disability was scored by the Quebec Back Pain Disability Scale (QBPDS), Fear of movement by the Tampa Scale for Kinesiophobia (TSK). To explain the level of disability regression analyses were performed with disability as dependent variable and pain intensity, pain-related fear, and consecutively the level of physical activity in daily life and fluctuations in physical activity as independent variables. Results, based on 34 patients, showed that activity fluctuations (beta=0.373, p<0.05) rather than the mean activity level over time (beta=-0.052, ns) contributed significantly in explaining disability. The results are discussed in the light of current theories, previous research, and clinical implications.

Why do some patients keep hurting their back? Evidence of ongoing back muscle dysfunction during remission from recurrent back pain

Approximately thirty-four percent of people who experience acute low back pain (LBP) will have recurrent episodes. It remains unclear why some people experience recurrences and others do not, but one possible cause is a loss of normal control of the back muscles. We investigated whether the control of the short and long fibres of the deep back muscles was different in people with recurrent unilateral LBP from healthy participants. Recurrent unilateral LBP patients, who were symptom free during testing, and a group of healthy volunteers, participated. Intramuscular and surface electrodes recorded the electromyographic activity (EMG) of the short and long fibres of the lumbar multifidus and the shoulder muscle, deltoid, during a postural perturbation associated with a rapid arm movement. EMG onsets of the short and long fibres, relative to that of deltoid, were compared between groups, muscles, and sides. In association with a postural perturbation, short fibre EMG onset occurred later in participants with recurrent unilateral LBP than in healthy participants (p=0.022). The short fibres were active earlier than long fibres on both sides in the healthy participants (p<0.001) and on the non-painful side in the LBP group (p=0.045), but not on the previously painful side in the LBP group. Activity of deep back muscles is different in people with a recurrent unilateral LBP, despite the resolution of symptoms. Because deep back muscle activity is critical for normal spinal control, the current results provide the first evidence of a candidate mechanism for recurrent episodes.

Implications for Physical Activity in the Population With Low Back Pain

Low back pain is considered the most prevalent pain complaint affecting the general population, with a reported lifetime prevalence of up to 75%. It is a recognized societal problem from both a disablement and economic perspective, with costs exceeding that of coronary artery disease, respiratory infections, and diabetes. The traditional concept of low back pain having a favorable natural history paints an overly optimistic prognosis when considering recent epidemiological data. From a prognostic perspective, more than three quarters of individuals will have a recurrence of their symptoms within a year from the initial onset, and up to 40% report a permanent reduction in activity participation. Fear of movement and avoidance of physical activity participation have been associated with a less than desirable prognosis, often times leading to chronicity. Although numerous interventions with often contradictory findings have been described for the population with low back pain, a consensus of research has implicated the resumption and pursuit of appropriate physical activity as an efficacious intervention. This article reviews the current evidence pertaining to physical activity participation in the population with low back pain and provides recommendations for identifying individuals who may be at risk for chronicity resulting from fear and avoidance of activity.

A new episode of low back pain: who relies on bed rest?

Bed rest has been shown to be an ineffective treatment for non-specific low back pain (LBP). Despite this, during a new episode of pain some patients still rely on bed rest. Which patients choose bed rest is however unknown. The objectives of the present study were, firstly, to assess characteristics of patients choosing bed rest in (sub)acute pain and secondly to study whether prolonged bed rest in the (sub)acute phase of pain will result in long term disability. A prospective longitudinal cohort study included 282 patients with non-specific LBP for less than 7 weeks. Main outcome measures were duration of bed rest (in three categories) and disability. Results showed that 33% of patients with (sub)acute LBP had bed rest, but only 8% stayed in bed for more than four days. An ordinal regression analysis revealed that behavioural factors (catastrophizing (OR=1.05 per bed rest category p<0.01)) and fear of injury (OR=1.05 per category p<0.01) rather than specific pain related factors (pain history (OR=0.61 per category p=0.16) and pain intensity (OR=1.00 per category p=0.63)) were associated with bed rest. Patients with prolonged bed rest in an early phase of pain were still more disabled after one year (p<0.01). Based on these results we conclude that prolonged bed rest in the early phase of pain is associated with a higher long term disability level. In preventing low back disability, GP screening for catastrophizing and fear of injury in LBP patients who had prolonged bed rest merits consideration.