Vertebroplasty offers mild pain relief, but no functional improvements

While vertebroplasty provided moderate pain relief to patients suffering from osteoporotic vertebral compression fractures, the treatment offers no improvement to functional disability, according to a study published online May 21 in Radiology.

The findings represent the one-year outcomes of the Investigational Vertebroplasty Safety and Efficacy Trial (INVEST), which aimed to assess the treatment method—which involves the injection of polymethylmethacrylate into the fractured vertebral body—since it has become part of routine therapy, explained Bryan A. Comstock, MS, of the University of Washington in Seattle, and colleagues.

INVEST is a blinded, randomized, controlled trial conducted at 11 sites in the U.S., U.K. and Australia. A total of 131 participants were assigned to undergo vertebroplasty (68 patients) or a control procedure (63 patients), with the option to cross over to the alternate procedure after one month.

In an intention-to-treat (ITT) analysis, where outcomes were analyzed according to randomized group, Comstock and colleagues reported no difference between groups in regards to functional disability at one year, though vertebroplasty patients reported significantly less pain.

An as-treated (AT) analysis, which analyzed data according to the treatment actually received over the course of the study, neither functional disability or pain outcomes at one year varied significantly between the groups, according to the authors.

Crossover between treatments mainly occurred between one and three months after randomization, with 60 percent of control subjects crossing over to vertebroplasty. This complicated the interpretation of the ITT analyses, according to Comstock and colleagues. “Specifically, if vertebroplasty is in fact more effective than the control procedure, then one would expect to observe a diluted treatment effect, or no difference, in ITT analyses. However, subjects in the control group who subsequently crossed over and underwent vertebroplasty clearly did not experience similar outcomes to those initially randomized to vertebroplasty.”

In the AT analysis, functional disability improved from baseline to three months, and the authors speculated some combination of the placebo effect and natural history may have resulted in improvements through three months.

The authors noted one limitation of the study was that it was not adequately powered to identify subgroups of patients for whom vertebroplasty may be more beneficial.

“With a modest benefit toward pain and no benefit toward functional disability at one year, the role of vertebroplasty in the treatment of painful vertebral compression fractures warrants further study; future blinded, randomized, controlled trials may help identify subgroups of patients for whom the procedure is both safe and effective,” concluded Comstock and colleagues.

For more discussion on the effectiveness of vertebroplasty, click here.