Employed to Treat Particularly Severe Osteoporatic Fractures,

¶ … employed to treat particularly severe osteoporatic fractures, and involves the injection of medical cement into the fractured vertebral structure. The paper examines the efficacy of this procedure.

The trial used to evaluate vertebroplasty was title INVEST, or the Investigational vertebroplasty Safety and Efficacy Trial.

The trial took 131 randomly-assigned patients who each had 1-3 vertebral compression fractures (between vertebral levels T4 and L5), inadequate pain relief from standard medical procedures, and a level of pain equal to or greater than 3 on a scale of 0-10. The actual test had them undergo either the vertebroplasty procedure or a similar one. The alternate procedure represented the control group.

The pool of 131 patients was narrowed down from an initial pool of 1813 possible patients. The pool was narrowed using a number of factors, including: those who declined to participate, those with dementia, and those with a pain level greater than 3 on the 0-10 scale.

All of the patients selected a minimum of 50 years of age, and their fractures had to be at least 1-year-old; this is because the success of vertebroplasy is predicated on fractures whose duration is at least 1 year.

Results were evaluated using the Roland-Morris questionnaire (with results reported on a 0-23 scale, with the higher the number the more severe the pain felt by the patient) and a simple pain assessment by the patient on a 0-10 scale (with higher totals denoting greater pain felt.)

The patients were enrolled at 5 centers in the United States, 5 in the United Kingdom, and 1 in Australia. The specific sites were chosen primarily due to the capabilities of the research coordinator and the investigator, not necessarily due to the reputation of the centers.

A number of criteria were used to disqualify prospective patients from inclusion in the study; these included patients who were uncertain of their age, those with suspected neoplasm in the vertebral body in question, patients with dementia, those with marrow edema or those with vertebral-body uptake.

All patients agreed to partake in the study, signing informed consent forms.

The study focuses most heavily on the results after 1 month, although it also describes the finding following 3, 14, and 90 days.

In order for the results to be deemed statistically significant, it had to show that patients had a decrease of 30% or more on the RDQ scale.

On the day before the end of the trial, patients were asked to guess which procedure they had undergone and to rate their confidence in their guess on a scale of 0-10 (the higher the number the greater their confidence.)

Vertebroplasty practitioners were universally well-experienced, having performed an average of 250 procedures. It should be noted, however, that the average may be skewed by outliers, since the range went from a minimum of 50 to a maximum of 800 procedures.

In order to ensure that the groups were balanced, stratified, blocked randomization was employed. Additionally, study group specifications were concealed from not only the patients but also the study personnel who conducted follow-up assessments during the study. This ensured that not bias arose during the course of the study.

All patients were consciously sedated and then randomly assigned to either the experiment group or the control group. There were 68 patients assigned to the vertebroplasty group and 63 to the control group. There were few differences between those in each of the groups; the average age of those in the vertebroplasty group was 73.4, while the average for those in the control group was 74.3. A majority (roughly 2/3) of patients in both groups were Caucasian.

Logistic-regression models were used to determine the baseline and site values for patients who had at least a 30% improvement in the RDQ rating and the pain score.

The blinded study results were monitored in intervals of every 6 months in order to protect the safety of the clients and monitor any deaths or serious illnesses.

In order to determine treatment efficacy, O'Brien-Fleming stopping rules of

Statistical significance was determined through a P. value of less than 0.043; all P-values were two-sided.

One patient from the vertebroplasty group and two from the other group switched groups before one month.

There was no statistically significant difference in the results between the two groups. For the vertebroplasty group, the average RDQ score was 12.0+-6.3, compared to 13.0+-6.4 in the control group. With regard to the pain level test, the average score in the vertebroplasty group was 3.9+-2.9, compared to 4.6+-3.0 in the control group.