Low back pain may be caused by disturbed pain regulation: a cross-sectional study in low back pain patients using tender point examination.

BACKGROUND

Widespread pain has negative influence on outcome in low back pain (LBP) patients. Tender point (TP) examination is a standardized examination method to estimate diffuse tenderness.

AIMS

To assess diffuse tenderness by means of a standardized TP examination and to analyse for associations between the number of TPs and spinal structural changes as well as psycho-social factors.

METHODS

Patients sick-listed 3-16 weeks due to LBP with or without sciatica completed a questionnaire and went through a clinical low back examination and TP examination. Of 326 patients 111 had verified nerve root affection and 215 had non-specific LBP with or without radiating pain. Disc height reductions were estimated on lateral X-rays.

RESULTS

Multivariate logistic regression analysis showed that more than 8 TPs were strongly negatively associated with disc degeneration (Odds Ratio (OR) 0.58 (0.40-84), 95% Confidence Interval (CI): 0.39-0.84, p=0.004) and verified nerve root affection (OR 0.15 (0.04-0.54), p=0.004) and were positively associated with number of years since first episode of LBP (OR 1.05, CI: 1.01-1.09, p=0.009). Furthermore, more than 8 TPs were positively associated with widespread pain, female sex and bodily distress. With all patients included, bodily distress and the number of tender points were positively associated with the intensity of LBP, but disc degeneration was only positively associated with LBP in patients with less than 6 TPs.

CONCLUSIONS

The pain in patients with diffuse tenderness was rarely related to disc degeneration or nerve root affection, rather it may be caused by disturbed pain regulation.