title: The causality field (extrinsic and intrinsic factors) in industrial subacute low back pain patients.
abstract: In a prospective, randomized study, primarily designed to test the efficacy of activation on consecutive blue-collar workers sick-listed for 6 weeks due to subacute low back pain, 25% of the workers were excluded for medical reasons. In the intervention study (n = 103), only a minority of cases (6%) had 'true' subacute complaints, i.e. no prior history of low back pain. Subjective reports on general well-being, health status and work-related ergonomic factors were significantly lower or worse in patients than in reference samples. The randomized intervention study could establish a significant effect of graded activation on work return, but the effect seemed to be restricted to patients moderately disabled, i.e. one-third of the subacute low back pain patients included. A predictive four-factor model on work return increased the possibility of identifing nonresponders (chronic low back pain) more than threefold with a specificity (91%) and sensitivity (74%) comparable to that of clinical disc herniation. The history of a prolonged disablement process, cognitive factors, pain behavior and mentally straining ergonomic factors seemed to be of importance. Psychological reactions, or 'barriers to recovery', were slightly different in treatment and control groups but the type of intervention did not significantly alter the predictive model, suggesting that subsets of the study sample may benefit from other optional functional approaches. Descriptive characteristics of the study sample emphasized that subacute low back pain patients cannot be conceptualized as a homogeneous group. Four sub-groups could be identified: (a) specific medical disorders; (b) spontaneous recovery group; (c) moderately disabled back pain patients; and (d) nonresponders. The results support proposals that treatment should be tailored according to individual needs and that better case management should have priority for those belonging to the nonresponder group.
authors.affiliation: Department of Orthopaedics, Institute of Surgical Sciences, Göteborg University, Sweden.
authors.forename: C
authors.initials: C
authors.lastname: Ohlund
authors.forename: I
authors.initials: I
authors.lastname: Lindström
authors.forename: C
authors.initials: C
authors.lastname: Eek
authors.forename: B
authors.initials: B
authors.lastname: Areskoug
authors.forename: A
authors.initials: A
authors.lastname: Nachemson
mesh_terms: D000328:Adult; D015984:Causality; D006801:Humans; D017116:Low Back Pain / Q000453:epidemiology*; D008875:Middle Aged; D009784:Occupational Diseases / Q000453:epidemiology*; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D018582:Sick Leave