It has been more than 30 years since the first cement injections into vertebral bodies were performed and there is still an active debate about the appropriate indications, accurate complication and risk profiles, and the long-term impact on subsequent fractures.
Scott D. Boden
In the last decade, a newer technique to inject vertebral cement under lower pressure following balloon expansion of the fractured vertebrae has also become popular. Despite its popularity, increased utilization and successes and failures, there is still not uniform agreement as to the indications and long-term benefit of cement injection procedures for vertebral compression fractures.
Nuances of patient selection
Several clinical trials have failed to show a benefit of cement injections for treatment of vertebral compression fractures. Most of these studies have included the buzzwords that often imply “absolute truth” — prospective, randomized, controlled and blinded. These conclusions have implied current practices may overuse these interventions. Yet, despite multiple trials showing little to no benefit, physicians continue to perform cement injection procedures as a treatment for painful vertebral fractures. Why the blatant disregard for seemingly ironclad data?
Most clinicians recognize that the nuances of patient selection for various interventions are a key determinant of their success. Unfortunately, clinical trials by design, force patients into or out of study groups based on a list of rigid criteria (e.g., time since fracture, age, pain level, etc). Furthermore, clinical trials often have more inclusive criteria to help increase enrollment. A clinical trial on vertebroplasty or kyphoplasty might not differentiate a patient who has continued back pain 6 weeks after fracture that was worsening from a patient who has 50% improvement. Clearly, the benefit of a cementation procedure in those two hypothetical situations would be different. Trials also have not necessarily had consistent means to verify that back pain was related to the compression fracture, which has been a limitation.
A favorable risk-benefit ratio
Most clinicians who care for patients with spinal vertebral fractures have first-hand or second-hand observed a patient with a painful vertebral compression fracture literally walk pain free off the table following a cement injection. Like most medical treatments, success is often dependent on matching the right intervention to the right subset of patients. In the case of cement injections for vertebral fracture, consideration should be given to patients with pain that prevents them from mobilizing out of bed where bedrest itself poses risk.
Another consideration would be patients who have pain with minimal improvement at 4 weeks to 6 weeks despite orthotic treatment or medication. It is my opinion that the subacute, but not chronic cases, are the cases that provide the best opportunity to demonstrate a favorable risk-benefit ratio.
In an era of increasingly evidence-based medicine and value-based health care, it would be tragic to assume a lack of evidence of effectiveness for a treatment definitively implies it is not effective. While we must respect the power and strength of prospective, randomized, controlled and blinded trials, we must also recognize that the groups in studies are often heterogeneous in some of the clinical intangibles of patient selection. The ongoing evaluation of cement injections for vertebral fracture should focus on defining clear subgroups and clinical scenarios for which these injections provide a convincing risk-benefit cost ratio.
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Scott D. Boden, MD, is the Chief Medical Editor, Orthopedic Surgery for Spine Surgery Today. He can be reached at Spine Surgery Today, 6900 Grove Rd., Thorofare, NJ 08086; email: firstname.lastname@example.org.
Disclosure: Boden has no relevant financial disclosures.