In their report titled “Impact of Nonoperative Treatment, Vertebroplasty, and Kyphoplasty on Survival and Morbidity After Vertebral Compression Fracture in the Medicare Population,” Chen et al. present important information that may cause us to reconsider how we manage individuals who have an osteoporotic compression fracture that is severe enough to necessitate hospital admission. The authors analyzed the records for a very large group of inpatients with osteoporotic compression fractures with use of the 2006 Medicare Provider Analysis and Review File database.
For the sake of full disclosure, although I have no financial relationship related to these procedures, I do receive research funding from a company (SI-BONE, San Jose, California) that was started by the individual who was instrumental in bringing the kyphoplasty procedure to market.
The current study compared various outcomes at various time points for patients who underwent kyphoplasty or vertebroplasty with those for patients who were managed nonoperatively. The outcomes included mortality, destination following discharge from the hospital, hospital readmission, and a number of complications for which information could be gathered. Hospital charges, but not payments, were also evaluated. The general take-home points were that patients who were managed with kyphoplasty generally fared better than those who were managed with vertebroplasty and that patients who were managed with vertebroplasty generally fared better than those who were managed without either procedure. There were often large differences between the kyphoplasty group and the nonoperative treatment group. For example, the patients in the kyphoplasty group stayed in the hospital roughly half as long as those in the nonoperative treatment group and went to a skilled nursing facility at a rate less than half that of the patients in the nonoperative treatment group. Mortality, although high for all groups, was significantly lower at all time points in the kyphoplasty group.
These findings are somewhat different from those of other well-known studies of vertebroplasty and kyphoplasty. Comparing some of those studies with this one seems worthwhile. Possibly the two most referenced studies were published in 2009 in the New England Journal of Medicine1,2. Both were prospective, multicenter, randomized trials comparing vertebroplasty with sham treatment, primarily in outpatients. Those trials involved far smaller groups of patients, and recruitment took place over the course of years. The duration of follow-up was far shorter, with one study analyzing primary outcomes at one month1 and the other study analyzing primary outcomes at three months2. Although one study demonstrated a trend toward reduced pain associated with vertebroplasty, neither study showed significant differences in outcome between vertebroplasty and a sham procedure. Mortality was quite low in both studies. In one study, the mortality rate at three months was two of thirty-eight in the vertebroplasty group and one of forty in the placebo group. The other study did not specifically discuss mortality, but sixty-four of sixty-eight patients in the vertebroplasty group and sixty-one of sixty-three patients in the placebo group were evaluated. I believe that it is reasonable to assume that the mortality rate in that study was 0% or close to it. The current study evaluated mortality during hospitalization, at one year, and at three years. Mortality was quite low during hospitalization, but at one year the survival rate had decreased to 73% in the nonoperative treatment group, 79% in the vertebroplasty group, and 85% in the kyphoplasty group. Although the time frame for reporting mortality differed considerably between the studies, it is reasonable to conclude that the groups in the current study and those in the other two studies were different, which explains the difference in outcomes.
A prospective, industry-sponsored, multicenter study in which kyphoplasty was compared with nonoperative (but not placebo) treatment was published in 2009 in The Lancet3. In the analysis of primary outcome measures in that study, kyphoplasty showed significant superiority at one month but with diminution of the difference by one year. The survival rate at one year was 94% in the kyphoplasty group and 95% in the nonoperative treatment group. Once again, the large difference in survival rates suggests that the groups were different.
This difference is important because, as stated earlier, I think that reconsideration is indicated. In 2010, the American Academy of Orthopaedic Surgeons (AAOS) released a clinical practice guideline for the treatment of symptomatic osteoporotic spinal compression fractures4. On the basis of evidence that was classified as strong, including the two vertebroplasty studies discussed previously, the AAOS recommended “against vertebroplasty for patients who present with an osteoporotic spinal compression fracture on imaging with correlating clinical signs and symptoms and who are neurologically intact.” On the basis of evidence that was classified as weak, the AAOS recommendation was that “Kyphoplasty is an option for patients who present with an osteoporotic spinal compression fracture on imaging with correlating clinical signs and symptoms and who are neurologically intact.”
The group reviewing the available information did a thorough job of making recommendations based on higher-level evidence, which is less likely than lower-level evidence to be refuted by future studies. The present study certainly had some weaknesses: it was a retrospective study, it did not include any information about clinical decision-making as to why some patients received augmentation procedures whereas others did not, and it included only patients who were covered by Medicare. The study also had strengths, including access to a very large number of patients and reliable outcome information. The study showed, at least to me, striking differences from prior studies with regard to mortality, hospital stay, and destination at the time of discharge.
On the basis of this compelling study that looked at a somewhat different population of patients in a somewhat different way, the use of cement augmentation should be considered reasonable and indicated care, at least for patients who are hospitalized for osteoporotic compression fractures.
The other issue to reconsider is that of vertebroplasty compared with kyphoplasty. As noted in the AAOS clinical practice guideline, there was weak evidence for the use of kyphoplasty in the appropriate patient. I was generally of the opinion that there was probably no true, clinically relevant difference between the two procedures. The current study has pushed me to reconsider this opinion. Once again, we are looking at a retrospective, nonrandomized, noncontrolled study. We have no information as to why some patients being managed with cement augmentation underwent kyphoplasty and some underwent vertebroplasty, but we have moderately strong evidence that the patients who underwent kyphoplasty generally did better, in almost every outcome measured. To me, this is a moderately strong argument in favor of kyphoplasty over vertebroplasty and is a very strong argument for the consideration of the use of kyphoplasty for the patient who has been hospitalized because of symptomatic osteoporotic compression fracture(s).