Efficacy of zoledronic acid following PLIF in patients with osteoporosis

Study Type: Therapy
OE Level of Evidence: 2
Journal Level of Evidence: N/A
79 patients with osteoporosis scheduled for instrumented posterior lumbar interbody fusion due to single-level degenerative spondylolisthesis were randomized to be postoperatively administered either zoledronic acid or saline. The purpose of this study was to compare groups based on fusion status, the incidence of a subsequent vertebral compression fracture, clinical outcome, serum biomarkers of bone metabolism, and femoral neck bone mineral density over the first year after surgery. Results demonstrated a Please login to view the rest of this report. Please login to view the rest of this report.
Funding: Non-Industry funded
Sponsor: Fundamental Research Funds for the Central Universities; Science and Technology Plan of Hunan Province; National Institutes of Health
Conflicts: None disclosed
Why was this study needed now?
Instrumented spinal fusion surgery is often utilized in cases of spinal degeneration and trauma. These procedures can be complicated by osteoporosis, which may put patients at a greater risk of complication. Anti-osteoporosis drugs, such as bisphosphonates, are often prescribed for patients with osteoporosis, though their acceptability in cases of spinal fusion surgery has been questioned, with previous research evaluating alendronate demonstrating inconsistent results. Zoledronic acid may provide different results as compared to alendronate, however, few trials have evaluated the potential benefits of this drug for spinal fusion patients with osteoporosis. A randomized controlled trial was needed to determine the impact of zoledronic acid in this patient population.
What was the principal research question?
In patients with osteoporosis undergoing instrumented single-level posterior lumbar interbody fusion, does administration of zoledronic acid lead to significant improvement in the rate of solid fusion, disability, and biomarkers of bone turnover and formation when compared to saline administration, assessed over a 1-year follow-up?
Population: 79 patients with symptomatic single-level degenerative spondylolisthesis (low back pain/leg pain for longer than 3 months duration) and scheduled for instrumented posterior lumbar interbody fusion (PLIF). Additional eligibility criteria included a diagnosis of osteoporosis (bone mineral density T-score <-2.5 at the lumbar spine or femoral neck). PLIF procedures were standardized across groups and instrumented with pedicle screws and rods. In addition, all patients received 1000mg calcium and 800IU vitamin D daily postoperatively.
Intervention: Zoledronic acid group: Following surgery, patients received intravenous infusion of 5mg of zoledronic acid. (n=39 randomized; 33 analyzed at 1 year) (Mean age: 65+/-8)
Comparison: Control group: Following surgery, patients received intravenous infusion of saline. (n=40 randomized; 36 analyzed at 1 year) (Mean age: 63+/-7)
Outcomes: Coronal and sagittal computed tomography (CT) scans were used to assessed fusion status and graded as A (bone bridging with both superior and inferior vertebral levels), B (bone bridging with either superior or inferior vertebral levels) or C (incomplete bone bridging). Flexion-extension radiographs were obtained to assess angular motion of the fused segment. Solid fusion was defined as <5deg angular motion and the presence of grade A or B fusion. Magnetic resonance imaging (MRI) was also performed to assess the development of any subsequent vertebral compression fracture. Clinical outcome evaluation was performed using the Oswestry Disability Index (ODI). Bone resorption was assessed using serum carboxy terminal cross-linked telopeptide of type I collagen (Beta-CTX) levels, and bone formation with serum amino-terminal propeptide of type I procollagen (P1NP) levels. Dual energy x-ray absorptiometry (DXA) was used to assessed bone mineral density of the femoral neck.
Methods: RCT; prospective
Time: Follow-up scheduled at 3, 6, 9, and 12 months post-operatively.
What were the important findings?
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How will this affect the care of my patients?
The authors responsible for this critical appraisal and ACE Report indicate no potential conflicts of interest relating to the content in the original publication.