A randomized, double-blind, placebo-controlled trial of sclerosing injections in patients with chronic low back pain

Objective. To determine the clinical efficacy of sclerosing injections in p atients with chronic low back pain. Methods. Randomized, double-blind, placebo-controlled trial of three, once weekly injections of dextrose-glycerine-phenol with lignocaine vs saline pl us lignocaine in patients with mechanical back pain of more than 6 months' duration. All patient assessments were performed blind by an experienced ph ysiotherapist. The injections to the ligaments of the L4-5 and L5-S1 lumbar motion segments were given by an orthopaedic physician experienced in the technique, blinded to the nature of the injection solution according to a s tandard protocol. Demographic and clinical data, the short-form McGill Pain Questionnaire, the modified Somatic Pain Questionnaire, the Zung Depressio n Inventory, Oswestry Disability Scale and the modified Schober method of m easuring spinal flexion were undertaken at 0, 1, 3 and 6 months. Results. Seventy-four patients [mean (S.D.) age 45(11)yr, female:male ratio 1:1, median pain duration >10 yr] were recruited and there were no drop-ou ts over the study period. There were no statistically significant differenc es in patient characteristics between the placebo and treatment groups at b aseline or for any measure at follow-up. Conclusions. Three, weekly sclerosant injections alone may not be effective treatment in many patients with undifferentiated chronic back pain. Patien t selection and combination with other treatment modalities may be factors in determining treatment success.