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)

Study Subjects

Consecutive patients presenting to our clinic for consideration of vertebroplasty for painful vertebral compression fractures were screened for enrollment between April 2009 and January 2010. The trial was called “LABEL.” Institutional review board approval was obtained before the start of this Health Insurance Portability and Accountability Act−complaint study, and informed consent was obtained from all study participants. Inclusion criteria were the following: 1) age >40 years, 2) ≤4 osteoporotic fractures of <12 months' duration, 3) pain score of at least 3 of ten, 4) English-speaking participants who had access to a telephone, 5) ability to give informed consent, and 6) a normalized International Normalized Ratio. Patients were excluded if they had local infection, tumor involvement of the vertebra to be treated, diagnosis of multiple myeloma, or were women of child-bearing potential.

Patient Evaluation

LABEL was an unblinded observational cohort study of patients presenting for consideration of vertebroplasty at our Neuroradiology Clinic. Patients were evaluated for appropriateness of vertebroplasty and were counseled that the true efficacy of the cement injection has not been proven. Patients were counseled that recent data suggest that a substantial portion of patients may benefit from local anesthesia without cement injection. At the time of consent, they were told that they could ask for and obtain a vertebroplasty at any time during follow-up.

Collection of Baseline Variables

Baseline data collection included age and sex. Outcome measures collected at baseline included the modified 23-question RDQ^3–5 and a 0–10 rating of average pain during 24 hours, pain with activity, and pain at rest.

Procedural Characteristics

After screening and consent signature, patients were escorted to a fluoroscopy room. They were instructed regarding routine postprocedural concerns, including delayed allergic reaction and bleeding. All procedures were performed under strict aseptic conditions. Patients were placed prone on a fluoroscopy table. Standard fluoroscopy was used for localization of the vertebral body/bodies to be treated (levels T4-L5). A 1-inch 25-gauge needle was used to raise a wheal of 0.25% lidocaine subcutaneously. A 10-cm 25-gauge spinal needle was placed into the skin at the site of the wheal and advanced under fluoroscopic guidance to the periosteum over the pedicle. This periosteum was then infiltrated with 6–7 mL of 0.25% bupivacaine. Injections were made at each fracture level. As is typical for our vertebroplasty practice, unipediculate injections were performed at each level.

Follow-Up

Follow-up outcome measures included RDQ score, average pain during 24 hours, pain with activity, pain at rest, and patient decision to undergo vertebroplasty. Patients enrolled in LABEL were followed at prescheduled intervals similar to the INVEST: days 1, 3, and 7, two weeks, 1 month, and 3 months. Follow-up in this trial continued until 3 months or the patient underwent vertebroplasty, whichever came first. Due to early crossover to vertebroplasty, we only reported on outcome measures observed through day 3. If desired by the patient, he or she was prescheduled for vertebroplasty at the time of enrollment into the LABEL trial. These vertebroplasty procedures were typically prescheduled for 1–7 days following the initial evaluation.

INVEST Control Group Data

Only data from patients from the lead site of INVEST were included in this analysis. The study methods have been described previously.^2,6 The inclusion criteria for these patients were similar to those of LABEL and were the following: 1) The patient must be 50 years of age or older; 2) He or she should have a diagnosis of 1–4 painful osteoporotic vertebral compression fractures between vertebral levels T4 and L5; 3) inadequate pain relief with standard medical therapy; 4) a rating for pain intensity of at least 3 on a 0–10 scale; and 5) the fracture needed to be <1 year old. Exclusion criteria were evidence or suspicion of a neoplasm in the target vertebral body, retropulsion of bony fragments, concomitant hip fracture, active infection, and uncorrectable bleeding diatheses.

The INVEST control group underwent a blinded sham vertebroplasty with injection of lidocaine and bupivacaine. With the exception of the sham vertebroplasty procedures, the process of injection of local bupivacaine and lidocaine was identical to that of the LABEL study. The methods of blinding and injection of local anesthesia are described elsewhere.^2,6

Statistical Analysis

Statistical analysis was performed by using the SAS-based statistical package JMP (www.jmp.com). For determination of the significance of improvement in the RDQ score, average pain during 24 hours, average pain with rest, and average pain with activity scores at days 1 and 3 were subtracted from the respective baseline scores. A paired t test was performed with the null hypothesis being no difference in scores at days 1 and 3 compared with baseline. For comparison of outcome measures between patients enrolled in the LABEL study with patients enrolled in the control arm of the INVEST, we used 2-sample t tests on the change from baseline scores. Means are presented with their associated SDs.