Vertebral Augmentation: Supported by Randomized Controlled Trials or Not?

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New Orleans—Is percutaneous vertebral augmentation an effective treatment modality to reduce the pain of vertebral compression fractures (VCF)? Two pain experts squared off on opposing sides of this issue in a session at the 10th Annual American Society of Regional Anesthesia and Pain Medicine Fall Pain Meeting in November.

“Vertebral augmentation doesn’t do squat,” said Oscar A. de Leon-Casasola, MD, professor of anesthesiology and medicine at the University of Buffalo and chief of pain medicine and professor of oncology at Roswell Park Cancer Institute, both in Buffalo, N.Y.

Allen W. Burton, MD, practicing pain medicine specialist and anesthesiologist at Houston Pain Associates, countered, stating, “Considerable level 1 evidence supports vertebroplasty and balloon kyphoplasty.”

Dr. Burton pointed out that several professional societies have called vertebral augmentation safe, effective and durable for appropriate patients and have said the benefits outweigh both the procedural risk and the risks associated with conservative therapy. Prime candidates for vertebral augmentation have axial or mechanical pain from a recent fracture (in the last three to 12 months) as well as concordant movement-related pain. Indications include painful osteoporotic VCF refractory, painful vertebrae due to benign or malignant bone tumors or painful VCF with osteonecrosis. Dr. Burton emphasized that people with painful acute VCF do not just get better and need treatment.

Two Studies, “Fatal” Flaws

Dr. de Leon-Casasola spoke against vertebroplasty by describing the results of two studies published in the New England Journal of Medicine (2009;361:557-568 and 2009;361:569-579) that evaluated the efficacy of bone cement in vertebroplasty for painful osteoporotic fractures compared with a sham procedure in patients with spinal fractures less than 12 months old.

In one of the studies, investigators randomized participants with one or two painful osteoporotic vertebral fractures that were unhealed and less than 12 months old to undergo vertebroplasty or a sham procedure. The primary outcome was overall pain (on a scale of 0 to 10, with 10 being the maximum imaginable pain) at three months.

Overall, 71 people (35 in a vertebroplasty group and 36 in a placebo group) completed the six-month follow-up. The investigators found that vertebroplasty did not result in a significant advantage in any measured outcome at any time point; disability measures and other health-related outcomes and opioid consumption also were similar in the two groups.

In the other trial, investigators randomly assigned 131 patients who had one to three painful osteoporotic vertebral compression fractures to undergo either vertebroplasty (n=68) or a simulated procedure without cement (n=63). At one month, there was no significant difference between the vertebroplasty group and the control group in pain outcomes. Both groups showed immediate improvement in disability and pain scores after the intervention. Additionally, in a one-year follow-up of this study population, there were no differences between treatment arms (Spine2010;35:478-482).

Dr. Burton maintained, however, that “fatal flaws” in the two New England Journal of Medicinetrials “tainted” the conclusion. “We should not throw out a good technique because of two flawed studies,” Dr. Burton told attendees. “I caution against worshipping blindly at the randomized controlled trial altar.”

Dr. Burton pointed to an editorial written by the North American Spine Society that took exception to the two studies, noting a “disconnect” between them and earlier studies (Spine J 2010;10:238-240). The editorial alleged that patient selection was not well controlled, the populations were enriched for patients with less severe pain, the sham procedures were equivalent to a facet block and the outcomes reporting was unduly complicated. Dr. Burton elaborated on these complaints, noting that screening 1,813 patients to enroll only 131 in one of the studies amounted to selection bias. He added that the trials were underpowered and that high crossovers from the sham procedure to vertebroplasty, and not the reverse, implied efficacy for the procedure.

“If these studies had a positive result, they would have been rejected for these reasons,” he maintained.

Not All Positive Studies Are Sponsored

Dr. Burton then described several trials that showed a benefit of vertebroplasty. VERTOS II, conducted in 202 patients with acute VCF and significant pain, found that vertebroplasty offered immediate and sustained pain relief and improvements in quality of life and disability at an acceptable cost (Lancet 2010;376:1085-1092).

“This study was sponsored by The Netherlands Organisation for Health Research and Development, the Dutch equivalent of our National Institutes of Health, which disputes the notion that all positive trials are industry-sponsored,” he added.

Two balloon kyphoplasty studies also showed results in favor of vertebroplasty. The FREE (Fracture Reduction Evaluation) trial found that balloon kyphoplasty provided greater improvements at one month than nonsurgical management, with results sustained through 12 months and improvements observed in six secondary outcomes (Lancet 2009;373:1016-1024).

“This was a large prospective study with rigorous criteria and lots of controls,” Dr. Burton noted.

A 2011 study found that balloon kyphoplasty was superior to nonsurgical management (Lancet Oncol 2011;12:225-235). At one month, patients randomized to the kyphoplasty group (n=65) experienced rapid back relief, with an 8.3-point improvement in back function as measured by the Roland-Morris Disability Questionnaire versus a mean change of 0.1 points in the control group (n=52). Additionally, 75% of patients in the kyphoplasty group reached the meaningful self-care threshold (≥70 score) compared with 39% in the control group. The most common adverse events within the first month were back pain (four of 70 in the kyphoplasty group and five of 64 in the control group) and symptomatic vertebral fracture (two in the kyphoplasty group and three in the control group).

“For painful VCFs in patients with cancer, balloon kyphoplasty is an effective treatment that rapidly reduces pain and improves function,” Dr. Burton maintained.

He further noted that minor complications are rare, major complications are very rare and the majority of complications are transient and self-limited. “Also, there are downsides to conservative care,” he added.

Statistical Improvement Only

Dr. de Leon-Casasola, however, questioned whether the differences seen in the positive trials were actually clinically meaningful. In VERTOS II, the difference in pain as measured by a visual analog scale was 2.6 at one month and 2.0 at one year, and analgesic use was reduced at one day, one week and one month, but thereafter the difference lost statistical significance. Furthermore, function was not improved, opioid consumption was similar and comprehensive medical management was not well defined.

“This was a statistical improvement only. Vertebral augmentation does not do anything after one month of the procedure, and the costs are significantly higher,” Dr. de Leon-Casasola concluded. “I have had patients who became pain-free after these procedures and have brought me fruit baskets, but a few months later they are back in my office.”

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