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The use of advanced imaging and representation of workers compensation in vertebral augmentation: a single-center comparison with the INVEST Trial.

BACKGROUND
Vertebral augmentation (VA) techniques have changed the paradigm of treatment during the past decade and involve injection of polymethylmethacrylate (PMMA) cement directly into a compressed vertebral body. During the summer of 2009, the INVEST trial was one of 2 randomized controlled studies that reported equivalence between vertebroplasty and a control procedure. 


OBJECTIVE
In this analysis, we sought to compare the subset of patients studied in the INVEST trial to a tertiary academic institution with respect to 2 variables: Workers compensation status and presence of advanced imaging prior to the procedure.


STUDY DESIGN
Retrospective review of 634 procedures.


METHODS
We performed a retrospective review of 634 vertebral augmentation procedures at our institution between June 2004 and August 2008, overlapping with the dataset of the INVEST trial. The primary comparison was whether patients received Workers compensation and/or advanced imaging prior to the procedure. The study was IRB approved, and in accordance with HIPAA guidelines.


RESULTS
There were 409 patients who underwent 634 procedures between June 2004 and August 2008. Among 634 procedures, only 3 included Workers compensation. Therefore, the majority of patients (> 99%) did not receive Workers compensation compared to the INVEST trial (11 - 13%). Similarly, in 629 out of 634 procedures (99.2%), patients underwent advanced imaging comprised of magnetic resonance imaging (MRI), computed tomography (CT) or bone scan.


LIMITATIONS
We simply looked at 2 elements of the patient demographic in a time-matched fashion and compared it to the U.S. based INVEST trial. It is possible that despite our diligent efforts to review the data set, we have inadvertently excluded some patients, the incorporation of whom might have changed the statistics.


CONCLUSION
We reviewed our time-matched database in terms of 2 variables we thought curious in the INVEST trial.  In comparison to our practice, where advanced imaging is essentially required and Workers compensation largely not seen, these aspects of the INVEST trial's population stood out.