Augmentation procedures for osteoporotic vertebral fractures--an ongoing experiment or emerging standard of care?

The history of vertebral augmentation procedures is an interesting one. Vertebroplasty was first performed in France in 1984 and reported in a French language journal in 1987. (1) This publication did not create great international attention, but served to initiate further investigation by others. It was not until 1994 that the procedure was performed in the US. When a retrospective review of 47 vertebroplasties in 29 patients with osteoporotic vertebral fractures was published in an English language journal a few years later, (2) it set in motion a series of events that led to a paradigm shift in clinical thinking about the management of vertebral fractures--from "benign neglect" to active intervention. A remarkable 90% of patients in that study were reported to have significant pain relief immediately after the procedure.

Kyphoplasty, a sister procedure of vertebroplasty, was first performed in 1998 and later reported to provide similar pain relief. (3) With this minimally invasive procedure, an inflatable balloon tamp creates a cavity within the fractured vertebral body, allowing a thicker material to be injected at lower pressure with less risk of leaking, as compared with vertebroplasty. Kyphoplasty offered an additional benefit over vertebroplasty--the possibility that lost vertebral height could be partially restored and the hope that this would prevent or improve kyphosis, thereby preventing some of the long-term complications of vertebral fractures, such as diminished pulmonary function. By the end of 2005, over 200,000 kyphoplasties had been performed in about 170,000 patients, with more than 7,400 physicians trained in the procedure worldwide. It is likely that the number of vertebroplasties performed in recent years has also increased greatly, although statistics on these are difficult to obtain.

In this issue of the Journal, Machinis et al (4) present a retrospective review of 37 vertebral fractures in 24 patients treated with kyphoplasty. This report adds to the expanding body of medical literature demonstrating that vertebral augmentation is associated with rapid pain relief and improved short-term quality of life (compared with preprocedure), with few adverse events. The apparent success of these procedures has led to the suggestion that vertebral augmentation should be the standard of care for patients with vertebral fractures that result in kyphosis and significant pain lasting more than a few weeks. (5) Others have proposed the use of vertebral augmentation prophylactically for patients with vertebral bodies that have not yet fractured but are at high risk to do so. (6) The high level of enthusiasm for these procedures is understandable. Vertebral fractures, especially those with high-grade deformities, may cause great distress to the patient and have serious long-term consequences. A safe, minimally invasive procedure that quickly relieves pain in most patients, seems to improve quality of life, and offers the possibility of maintaining pulmonary function and posture is extremely attractive. However, before accepting vertebral augmentation as a new standard of care, it is imperative to understand the long-term benefits and potential risks compared with alternative treatments. Most published reports to date have been retrospective case series. There are few prospective controlled studies and no published prospective randomized controlled studies.

Several ongoing clinical trials will provide a better understanding of kyphoplasty benefits and risks. The FREE (Fracture REduction Evaluation) study is a fully enrolled 2-year prospective randomized controlled multicenter trial comparing the outcomes of kyphoplasty versus medical therapy in 300 patients with acute painful vertebral fractures. CAFE (CAncer patient Fracture Evaluation), which has a similar study design, will evaluate the outcomes of kyphoplasty in up to 200 cancer patients with painful vertebral fractures. Other studies in progress will follow changes in pulmonary function in patients with vertebral fractures with and without kyphoplasty, and compare the outcomes of vertebroplasty versus kyphoplasty.

What do we know about augmentation procedures for vertebral fractures? We know that vertebroplasty and kyphoplasty are very effective at relieving vertebral fracture pain, and appear to do this well in fractures that are up to several years old. Pain relief seems to be independent of vertebral height restoration and the amount of bone cement injected. Both procedures are associated with a low risk of adverse events, both in the perioperative period and over the following months to several years. Following the procedure, most patients are satisfied with the results. However, we cannot fully compare the outcomes of vertebral augmentation versus medical therapy, or vertebroplasty versus kyphoplasty, since there are no published long-term randomized controlled studies. In addition, we do not know whether vertebral height restoration restores lost pulmonary function, decreases morbidity, or increases life expectancy. We do not know the best bone filler material. We do not know how the cost-effectiveness of vertebral augmentation compares to other treatments. We do not know the mechanisms of pain relief, and it is not clear whether these procedures increase the risk of fracture in adjacent vertebral bodies.

The bottom line, I believe, should be cautious optimism. Vertebroplasty and kyphoplasty are promising procedures that are likely to play a role in the management of vertebral fractures for the foreseeable future. That role will continue to evolve as we learn more. One or both of these procedures may eventually become the standard of care for some patients with vertebral fractures. However, this will not be achieved until prospective randomized controlled trials demonstrate superiority in comparison with other treatment options.

References

1. Galibert P, Deramond H, Rosat P, et al. Preliminary note on the treatment of vertebral angioma by percutaneous acrylic vertebroplasty. Neurochirurgie 1987;33:166-168.

2. Jensen ME, Evans AJ, Mathis JM, et al. Percutaneous polymethylmethacrylate vertebroplasty in the treatment of osteoporotic vertebral body compression fractures: technical aspects. AJNR Am J Neuroradiol 1997;18:1897-1904.

3. Garfin SR, Yuan HA, Reiley MA. New technologies in spine: kyphoplasty and vertebroplasty for the treatment of painful osteoporotic compression fractures. Spine 2001;26:1511-1515.

4. Machinis TG, Fountas KN, Feltes CH, et al. Pain outcome and vertebral body height restoration in patients undergoing kyphoplasty. South Med J 2006;99:457-460.

5. Neviaser A, Toro-Arbelaez JB, Lane JM. Is kyphoplasty the standard of care for compression fractures in the spine, especially in the elderly? Am J Orthop 2005;34:425-429.

6. Barr JD, Barr MS, Lemley TJ, et al. Percutaneous vertebroplasty for pain relief and spinal stabilization. Spine 2000;25:923-928.

A good laugh is sunshine in a house.
--William Makepeace Thackeray

E. Michael Lewiecki, MD, FACP 

From the New Mexico Clinical Research & Osteoporosis Center, Albuquerque, NM.

Reprint requests to E. Michael Lewiecki, MD, FACP, Osteoporosis Director, New Mexico Clinical Research & Osteoporosis Center, 300 Oak Street NE, Albuquerque. NM 87106. Email: [e-mail]

Accepted February 13, 2006.