Background: Up to 25 percent of adults older than 50 years will have at least one vertebral fracture in their lifetime. Although many spontaneously heal, some will cause chronic pain and disability that do not respond to conservative therapy. Vertebroplasty with injection of polymethyl methacrylate (PMMA) into the vertebral body has become a widely used treatment for vertebral fractures. This is based on data from observational and unblinded studies that suggested patients receive immediate and sustained pain reduction after the procedure. However, data from high-quality randomized controlled trials (RCTs) have been lacking.
The Study: Buchbinder and colleagues conducted a randomized, double-blind, placebo-controlled trial assessing the effectiveness of vertebroplasty in alleviating pain and improving physical functioning in patients with painful osteoporotic vertebral fractures. Participants had developed back pain within the previous 12 months and had one or two recent vertebral fractures. Exclusion criteria included spinal cancer, neurologic complications, destruction of the posterior vertebral wall, bony fragments impinging on the spinal cord, previous vertebroplasty, more than two recent vertebral fractures, and osteoporotic vertebral collapse of more than 90 percent.
Participants were randomly assigned to undergo vertebroplasty including PMMA injection into the fractured vertebral body via a 13-gauge needle, or a sham procedure in which an identical needle was inserted but no PMMA injection occurred. The interventional radiologist was made aware of the participants' assigned intervention immediately before the procedure, but had no other role in the trial. Participants were evaluated at one week, and one, three, and six months after the procedure for pain and quality of life indicators.
Results: Seventy-eight participants were randomized between the vertebroplasty and control groups. Both groups had similar decreases in pain over time, with approximately 50 percent of each group stopping opiate therapy at six months. No significant differences were noted in overall pain or quality of life, with the exception of total quality of life at one week, which favored the placebo group. These results were consistent regardless of symptom duration, sex, or whether participants had previous vertebral fractures.
Conclusion: Vertebroplasty for the treatment of painful osteoporotic spinal fractures showed no benefit compared with a sham procedure, initially or in the six months after treatment.
editor's note: The use of vertebroplasty for treating painful spinal fractures—including guidelines recommending its use1—has been based on observational studies that reported immediate and prolonged pain improvement after the procedure. This is one of two RCTs that have been published on the subject: the other is the INVEST trial, which reached the same conclusion that vertebroplasty is no better than a sham procedure.2 These findings reinforce the importance of using RCTs whenever possible to assess treatment effectiveness.
Uncontrolled and poorly controlled studies can overestimate treatment benefit, especially when an invasive procedure may raise expectations. Alternatively, both the treatment and control groups used a short-acting analgesic to infiltrate the periosteum during the procedure, raising the possibility that the analgesic, and not PMMA, could be responsible for the previously reported benefit of vertebroplasty. Future study on this aspect is needed.—k.t.m.