Natural History of Pain in Patients with Conservatively Treated Osteoporotic Vertebral Compression Fractures: Results from VERTOS II

Discussion

In this study, we found that 40% of conservatively treated patients with acute osteoporotic compression fractures still had disabling pain after 1 year, despite the higher class of pain medication used at various intervals. Optimal pain medication and supportive therapy were apparently not sufficient for pain relief in a large proportion of these conservatively treated patients. On the other hand, 60% of patients had sufficient pain relief with conservative therapy, almost all within 3 months after the acute fracture. We could not find any predictors for the development of chronic pain. In particular, baseline pain scores, number of fractures, and the degree or shape of vertebral compression had no influence on the development of chronic pain.

The proportion of patients with chronic pain after conservative treatment in the present study is higher than that in previous studies. This can partly be explained by differences in the definition of chronic pain: We defined chronic pain as VAS scores ≥4, while in other studies, including VERTOS II, patients with insufficient decrease in VAS scores were considered to have chronic pain. In these studies,^4,11,12 patients with sufficient pain relief could have absolute VAS scores at follow-up of ≥4.

In the natural history of pain after an acute vertebral compression fracture, the time point of 3 months may be of clinical significance. Patients with continuing pain at this time point may be candidates for vertebroplasty.

The effectiveness of vertebroplasty is currently under debate. Most results are based on retrospective observational studies.^7⇓⇓–10 Recently, 3 randomized controlled trials concerning vertebroplasty have been published with conflicting results. Investigators in 2 trials^11,12 concluded that there is no benefit to vertebroplasty over a sham placebo procedure involving the injection of local anesthetic into the area adjacent to the fracture. In the study by Buchbinder et al,¹² 78 patients with 1 or 2 painful osteoporotic VCFs were randomized to receive either vertebroplasty or a sham procedure, which included infiltration of anesthetic into the pedicular periosteum. The primary measured outcome was overall pain at 3 months. Despite significant reductions in overall pain in both groups, there was no significant advantage of vertebroplasty over the sham procedure.

In the study by Kallmes et al,¹¹ 131 patients with 1–3 painful osteoporotic VCFs were randomized to undergo either vertebroplasty or a simulated sham procedure, which included infiltration of anesthetic into the periosteum of the posterior lamina. The primary outcomes were RMD scores and average pain intensity during the preceding 24 hours at 1 month. Treatment-group crossover was permitted at 1 month. At this time, there was no significant difference between the 2 groups in either the RMD score or the pain rating. In the third trial, VERTOS II,⁵ vertebroplasty was compared with optimal conservative treatment in 202 patients with VCFs with bone edema on MR imaging, back pain for ≤6 weeks, and a VAS score for pain of ≥5. The primary outcome was pain relief at 1 month and 1 year. The authors concluded that in a subgroup of patients with acute osteoporotic vertebral compression fractures and persistent pain, vertebroplasty is effective and safe. Pain relief after vertebroplasty is immediate, is sustained for at least a year, and is significantly greater than that achieved with conservative treatment, at an acceptable cost.

Next to the lack of blinding in VERTOS II, the most important difference between the 2 sham studies and VERTOS II is patient selection. In the sham studies, both acute and chronic fractures were included, while in VERTOS II, only acute fractures were eligible. In addition, bone edema in the affected vertebra was not a consistent inclusion criterion in the sham studies. The sham studies lacked a control group without intervention. The discordant results from the sham studies, on the one hand, and VERTOS II, on the other hand, have incited much debate. Apparently clinicians still do not know how to best treat their patients. Medical societies understand the need for further randomized trials to support treatment decisions. Until then, on the basis of our findings, we believe it is justified to offer vertebroplasty to patients with compression fractures with insufficient pain relief after 3 months of conservative treatment.