Evaluation of influence of gender, occupational injury, and smoking on chronic low back pain of facet joint origin: a subgroup analysis.

The prevalence of persistent low back pain secondary to involvement of lumbosacral facet joints has been described in controlled studies as varying from 15% to 52% based on types of population and settings studied. Previous studies have shown variances in elderly populations, and postlumbar laminectomy patients. But no variations were observed in obese patients or patients with somatization disorder. Based on the individual results, it appears that facet joint pain may be less prevalent in patients with occupational injury and more prevalent in women and smokers. This analysis was based on a combination of the results of two previous studies with a total number of 320 patients to evaluate the influence of gender, occupational injury and smoking on prevalence of facet joint pain. Facet joints were investigated with diagnostic blocks initially using lidocaine 1%, followed by bupivacaine 0.25%, usually 2 to 4 weeks apart in these studies. The prevalence of facet joint pain in men was 38% (95% CI, 29% to 47%) compared to 43% (95% CI, 36% to 50%) in women; 43% (95% CI, 33% to 53%) in non-smokers, compared to 41% (95% CI, 30% to 52%) in heavy smokers; and 28% (95% CI, 18% to 38%) in occupational injury patients compared to 44% (95% CI, 36% to 52%) with a history of gradual onset. False-positive rates varied from 28% to 46%. In conclusion, based on the results of this evaluation, women and men, smokers and nonsmokers suffer with similar prevalence rates of facet joint pain in chronic low back pain; whereas occupational injury patients suffer with lesser prevalence (28%) compared to patients with gradual onset (44%) of low back pain.