Evaluation of role of facet joints in persistent low back pain in obesity: A controlled, prospective, comparative evaluation

Abstract

Chronic low back pain and obesity are two common medical conditions. Obesity has been associated with symptoms such as adverse fat distribution and multiple secondary disorders, including low back pain. Obesity is defined as being 30% over ideal weight, which influences normal body mechanics as well as recovery from an injury. Facet joints have been described as contributing to a significant proportion of patients suffering with persistent or chronic low back pain, variably from 15% to 45%. Since an obese patient is at a higher risk of disability compared to a patient with normal weight, obesity has been described as a confounding factor in persistent low back pain. This study included 100 patients, with 50 patients in Group I who were of normal weight and 50 patients in group II who were obese, by random allocation. Facet joints were investigated with diagnostic blocks using lidocaine 1% initially, followed by bupivacaine 0.25%. The results showed that the prevalence rate of facet joint pain in chronic low back pain in Group I or nonobese patients was 36%, in contrast to 40% in Group II, or the obese patient group, with no significant differences among the two groups. The study also showed a false-positive rate of 39% in the total sample, or 44% in Group I nonobese patients and 33% in Group II, or obese patients. It is concluded that the prevalence of lumbar facet joint mediated pain of 40% in obese patients and 36% in patients of normal weight with a false-positive rate of 33% in obese patients and 44% in nonobese patients is similar to the results of multiple previous studies concluding that facet joint mediated pain is a common occurrence in obese patients; however, the incidence of facet joint mediated pain is similar in obese patients and nonobese patients.