Vertebral Augmentation: Should We Be Doing It?

Low bone density has “gone viral.” With an aging population that is living longer, healthcare practitioners have seen a commensurate increase in the diagnosis of osteoporosis, which now affects an estimated 10 million Americans, while an additional 34 million are believed to have osteopenia. Because bone strength is related to density, it is not surprising that low bone mass increases the risk of fragility fractures. Osteoporotic vertebral compression fractures (OVCFs) are the most common fragility fracture in the United States, with approximately 750,000 new fractures diagnosed each year.

Fig. 1 Proportion of patients in each group with pain intensity less than four out of 10 on a numeric rating scale
Source: Clark W, Bird P, Gonski P, et al: Safety and efficacy of vertebroplasty for acute painful osteoporotic fractures (VAPOUR): a multicentre, randomised, double-blind, placebo-controlled trial. Lancet 2016;388:1408-16.

The controversy

In the 1990s, after learning of early success with cement augmentation in Europe, many U.S. physicians and surgeons began using it to treat OVCFs. The method was believed to reduce pain, improve daily function, and possibly maintain spinal alignment, further increasing its popularity and expanding its indications. However, the optimism was challenged in 2009 when Buchbinder et al., and Kallmes et al., independently published articles comparing percutaneous vertebroplasty (PVP) to sham procedures. Both groups arrived at similar conclusions: PVP provided no obvious clinical benefit over sham surgery.

The two articles had a profound impact on the way physicians and surgeons treated patients with OVCFs. Incorporating the data, AAOS published guidelines in 2010 strongly recommending against PVP for the treatment of OVCFs, as well as a limited recommendation for the use of balloon kyphoplasty (BKP) in OVCFs. The frequency of cement augmentation procedures performed annually in the United States declined precipitously. Smieliauskas et al., described a 52 percent reduction in the number of PVP procedures performed per capita, as well as a 40 percent reduction in the number of BKP procedures. It seemed the data had spoken, and physicians and surgeons listened: Cement augmentation was largely unnecessary to treat OVCFs.

However, since 2009, many publications have described the clinical benefit of cement augmentation procedures for the treatment of OVCFs. As a result, many physicians and surgeons have begun performing the procedures again. In May 2018, the results of the randomized, sham-controlled VERTOS IV trial once again declared similar outcomes in patients being treated with PVP and those treated with sham surgery. The dichotomy of information has muddied the waters yet again, leaving many of us scratching our heads and wondering whether cement augmentation is the right treatment for these patients.

When is treatment warranted?

Most OVCFs do not require treatment. A study by Ross stated that approximately 66 percent of OVCFs are asymptomatic or misleading with respect to location. Because of the typical low-energy mechanism of injury (e.g., sneezing, coughing, rising from a seated position), many patients do not associate their new-onset back pain with a fracture and, therefore, do not seek treatment until the pain persists. It is widely known that many OVCFs are not diagnosed at the time of injury but, rather, are found incidentally on imaging. Bartalena et al., reviewed the prevalence of OVCFs seen on imaging for nonspine-
related reasons; OVCFs were found incidentally on 21.6 percent of radiographs and 20.2 percent of CT scans, thereby highlighting the innocuous nature of these fractures.

Because OVCFs are seen so frequently and with such variability, treatment algorithms are vague at best. In a 2012 article, Lee et al., described a protocol to treat patients diagnosed with acute, painful OVCFs conservatively for three weeks; patients who failed to improve during that time were offered a BKP procedure. The authors found that nearly two-thirds of patients with painful, acute OVCFs improved over the three-week period. Those who were still symptomatic underwent a BKP procedure, which resulted in even greater reductions in pain at the one- and two-month time points compared to the patients who were successfully treated conservatively. By the three-month time point, both groups were doing similarly well. This is consistent with the results of the VERTOS II study published by Klazen et al., in 2010, in which 431 patients from six institutions in Europe were identified as having acute OVCFs. Of those, 229 (53 percent) had pain resolution without intervention. The remaining 202 patients were randomized to undergo PVP or receive conservative treatment. Statistically significant reductions in pain scores were seen in the PVP group immediately following the procedure and persisted throughout the first year following the procedure.

What the data show

In several other randomized, controlled trials, cement augmentation has been shown to be superior to conservative treatment for OVCFs. In 2011, Farrokhi et al., randomized 82 patients with acute OVCFs to receive either PVP or medical management. The authors followed patients for 36 months. Compared to the medically managed patients, the PVP group had statistically significant improvements in pain scores at one week, two months, and six months. Statistically significant improvements in quality-of-life scores also were observed in the PVP group at all time points, including at 36 months. In addition, fewer new OVCFs were seen in the patients treated with PVP compared to the medical management cohort.

In 2013, Comstock et al., published results of the INVEST trial, which followed 131 patients with OVCFs enrolled at 11 centers on three continents. Patients were eligible for inclusion if they failed to obtain adequate pain relief with medical management. Both the control and study cohorts had improvements in pain and function scores after one year. The authors concluded that although there was no difference in functional disability, a reduction in pain was seen in the PVP group.

In 2016, Clark et al., published results of the double-blind, placebo-controlled VAPOUR study, which compared PVP to placebo in the treatment of acute (less than six weeks) OVCFs. The researchers concluded that significantly more patients who had undergone a PVP had pain ratings of four out of 10 or less on a numeric rating scale compared to placebo, demonstrating the utility of PVP to help reduce pain in patients with symptomatic OVCF (Fig. 1).

Earlier this year, Zuo et al., published a meta-analysis of 18 studies using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) criteria to examine differences in pain relief following PVP, BKP, nerve block, or conservative treatment in patients with OVCFs. The results suggested that both PVP and BKP were able to better relieve pain than conservative treatment in acute, subacute, and chronic OVCFs in both the short (less than four weeks) and long (more than six months) term. Interestingly, despite multiple randomized, controlled trials and several meta-analyses supporting cement augmentation, Cochrane Reviews examining PVP in the treatment of OVCF published in 2015 and again in 2018 failed to find support for cement augmentation as a treatment option for OVCF. Of note, Buchbinder and Kallmes served as authors on the Cochrane Reviews.

Data regarding cement augmentation for OVCF had been overwhelmingly positive up until 2018, when Firanescu et al., concluded that PVP had no benefit in pain reduction compared to a sham procedure in patients with acute OVCFs. Although the data seem to suggest no role for PVP, closer inspection reveals that both PVP and the sham procedure (which involved the injection of local anesthetic into the pedicle and the vertebral body) significantly reduced patients’ pain at all time points, beginning one day after the procedure. Although this is hardly a ringing endorsement for PVP, the fact that the intervention provided significant reductions in pain cannot be ignored.

Summary

As previously mentioned, dozens of studies have evaluated the utility of cement augmentation to treat patients with OVCFs. Unfortunately, the disparate results within the literature make it difficult to determine the best treatment option. As surgeons, we must continue to evaluate patients individually and use our clinical judgement along with the evidence to formulate plans that are in the best interest of our patients.

Stuart Hershman, MD, is a fellow of AAOS. He is a clinical instructor of orthopaedic surgery at Massachusetts General Hospital and Harvard Medical School and a member of the AAOS Spine Program Committee.

References:

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  16. Zuo XH, Zhu XP, Bao HG, et al: Network meta-analysis of percutaneous vertebroplasty, percutaneous kyphoplasty, nerve block, and conservative treatment for nonsurgery options of acute/subacute and chronic osteoporotic vertebral compression fractures (OVCFs) in short-term and long-term effects. Medicine (Baltimore) 2018;97.
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A look at the literature

  • Eeric Truumees, MD

As someone with an interest in osteoporosis and vertebral compression fractures, I have followed the literature and practice regarding cement augmentation procedures for 20 years. The dichotomy between surgeons’ anecdotes and the published randomized, controlled trials is superseded only by the variation in clinical practice—from rare performance of the procedures to MRI reports routinely instructing referring primary caregivers to send patients to a neuroradiologist for a vertebroplasty. In fact, this condition could be a case study in the differences between effectiveness and efficacy research. The clinical trials teach us one thing: Patients most likely to experience major improvement after an augmentation procedure are also the least likely to agree to be randomized into a sham-controlled trial. Yes, most patients either do not know they have a fracture or rapidly improve. Yet a minority continues to report significant pain despite appropriate nonoperative management. Many of those patients improve after percutaneous cement augmentation. Our biggest failure remains inadequate attention to management of the underlying bone loss.

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