Local Anesthesia with Bupivacaine and Lidocaine for Vertebral Fracture trial (LABEL): a report of outcomes and comparison with the Investigational Vertebroplasty Efficacy and Safety Trial (INVEST).

BACKGROUND AND PURPOSE INVEST is a recently published double-blind placebo controlled randomized trial that demonstrated similar improvements in pain between blinded vertebroplasty and sham-vertebroplasty groups. LABEL is a trial determining the efficacy of pain relief of an injection of lidocaine and bupivacaine at the site of painful osteoporotic vertebral compression fractures in unblinded patients. We compared outcomes from the unblinded LABEL trial with those of blinded control patients from the lead site of the INVEST, exploring the role of blinding on the benefit of local anesthesia infusion for painful vertebral compression fractures. MATERIALS AND METHODS Nineteen patients with painful osteoporotic vertebral compression fractures underwent unblinded injection of lidocaine and bupivacaine at the site of painful osteoporotic vertebral compression fractures. Patients were given the option of undergoing vertebroplasty at any time following the procedure. Primary outcome measures were change in the RDQ and pain (at rest, with activity, and average 24-hour pain) at days 1 and 3 following the injection. Day 3 change in RDQ scores and change in average 24-hour pain were compared for LABEL and INVEST control patients from the lead site (n = 16). RESULTS Among patients in the LABEL trial, we detected no significant improvement in RDQ scores, pain at rest, and average 24-hour pain at days 1 and 3, whereas pain with activity improved significantly at both time points. INVEST control patients from the lead site experienced significantly greater improvement in average pain during 24 hours at days 1 (P = .03) and 3 (P = .04) and significantly greater improvements in RDQ scores at day 3 (P = .006) than patients from LABEL. CONCLUSIONS An unblinded injection of local anesthesia is ineffective in treating pain from osteoporotic compression fractures. This suggests that factors other than local anesthesia were responsible for the observed improvement in the control group in INVEST.