Prospective and Multicenter Evaluation of Outcomes for Quality of Life and Activities of Daily Living for Balloon Kyphoplasty in the Treatment of Vertebral Compression Fractures: The EVOLVE Trial

Abstract

Background: Osteoporotic and neoplastic vertebral compression fractures (VCF) are common and painful, threatening quality of life and increasing risk of morbidity and mortality. Balloon kyphoplasty is a percutaneous option for treating painful cancer- and osteoporosis-related VCFs, supported by 2 randomized trials demonstrating efficacy benefits of BKP over nonsurgical care.

Objective: To investigate 12-mo disability, quality of life, and safety outcomes specifically in a Medicare-eligible population, representing characteristic patients seen in routine clinical practice.

Methods: A total of 354 patients with painful VCFs were enrolled at 24 US sites with 350 undergoing kyphoplasty. Four coprimary endpoints-Numerical Rating Scale (NRS) back pain, Oswestry Disability Index (ODI), Short Form-36 Questionnaire Physical Component Summary (SF-36v2 PCS), EuroQol-5-Domain (EQ-5D)-were evaluated for statistically significant improvement 3 mo after kyphoplasty. Data were collected at baseline, 7 d, and 1, 3, 6, and 12 mo (www.clinicaltrials.gov registration NCT01871519).

Results: At the 3-mo primary endpoint, NRS improved from 8.7 to 2.7 and ODI improved from 63.4 to 27.1; SF-36 PCS was 24.2 at baseline improving to 36.6, and EQ-5D improved from 0.383 to 0.746 (P < .001 for each). These outcomes were statistically significant at every follow-up time point. Five device-/procedure-related adverse events, intraoperative asymptomatic balloon rupture, rib pain, and aspiration pneumonia, and a new VCF 25 d postprocedure, and myocardial infarction 105 d postprocedure were reported and each resolved with proper treatment.

Conclusion: This large, prospective, clinical study demonstrates that kyphoplasty is a safe, effective, and durable procedure for treating patients with painful VCF due to osteoporosis or cancer.

FIGURE 1.

Distribution of index and prevalent fracture levels. Index levels (those identified by investigators as treatment levels) and prevalent fractures (all radiographic fractures assessed by the core laboratory) are shown; prevalent fractures were identified from standing lateral x-ray films with 344 of 350 treated patients contributing data.

FIGURE 2.

Quality of life, disability, and pain assessments at baseline and after balloon kyphoplasty. Raw mean scores and 95% confidence intervals (CIs) are shown as ‘error bars’ for balloon kyphoplasty (solid lines) for A, SF-36 PCS (scale 0-100); B, total EQ-5D scores (scale 0-1); C, back pain (scale 0-10); D, ODI (scale 0-100); E, limited activity days (scale 0-14); F, bed rest days (scale 0-14). The P-value in each panel is for all postoperative visits. Below each panel, the n for each group is shown for baseline, 3, 6, and 12 mo as well as the group average for change from baseline and 95% CI (in parentheses) for 3, 6, and 12 mo. Please note that for the coprimary endpoints in panels A–D, the 95% CI are 1-sided, reflecting the critical lower bound while the upper bound is infinity. The 95% CI reflected in panels E and F are 2-sided. The dashed line indicates the average prefracture estimation from EVOLVE patients for that parameter.

FIGURE 3.

Index vertebral body kyphotic angulation correction and height restoration. Means and 95% CIs are shown for A, kyphotic angulation of index fractures; B, index fracture anterior height as a percent; C, index fracture midvertebral height as a percent; D, index fracture posterior height as a percent. p-values for change from baseline improvement are shown for each time point. Below each panel, the n for each group is shown for baseline, 3, and 12 mo.