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 patients 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 plus lignocaine in patients with mechanical back pain of more than 6 months' duration. All patient assessments were performed blind by an experienced physiotherapist. 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 standard protocol. Demographic and clinical data, the short-form McGill Pain Questionnaire, the modified Somatic Pain Questionnaire, the Zung Depression Inventory, Oswestry Disability Scale and the modified Schober method of measuring 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-outs over the study period. There were no statistically significant differences in patient characteristics between the placebo and treatment groups at baseline 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. Patient selection and combination with other treatment modalities may be factors in determining treatment success.