Design. Two hundred twenty-three consecutive adults with acute low back pai
n with or without referred spinal symptoms were treated conservatively and
followed prospectively for 1 year.
Objectives. To investigate the predictive value of centralization phenomeno
n (CP) with psychosocial variables previously identified as important risk
factors for patients with acute onset of nonserious or nonspecific low back
pain who subsequently develop chronic pain or disability.
Summary of Background Data. Psychosocial factors have been shown to be pred
ictors of chronic disability, but measures from physical examination rarely
predict chronic behavior. The authors of the present study investigated wh
ether dynamic assessment of changes in clinical measures during treatment c
ould be used to classify patients and predict occurrence of chronic pain or
disability.
Methods. Patients with acute symptoms and no history of surgery were treate
d by five physical therapists trained in McKenzie evaluation/treatment meth
ods. Seventy-three percent were receiving workers' compensation benefits. A
t initial evaluation and discharge, 23 independent variables were assessed
representing psychosocial, clinical, and demographic factors. Pain location
changes to repeated trunk movements were assessed at every visit. Patients
were placed in two groups: 1) those with pain that did not centralize and
2) those who completely centralized or demonstrated partial reduction of pa
in location with time. Treatment was individualized and based on McKenzie m
ethods. Patients were contacted at 12 months after discharge, and dependent
variables of pain intensity, return to work status, sick leave at work, ac
tivity interference at home, and continued use of health care were assessed
.
Results. Nine independent variables influenced pain symptoms or disability.
Pain pattern classification (non-centralization) and leg pain at intake we
re the strongest predictive variables of chronicity.
Conclusion. Dynamic assessment of change in anatomic pain location during t
reatment and leg pain at intake were predictors of developing chronic pain
and disability.