AAOS/NASS “Unalign” Over Vertebroplasty

The good Sister of Assisi Heights and Dowagers of the world are confused. Just a couple of years after the North American Spine Society (NASS), the world’s largest spine society, told them that vertebroplasty and kyphoplasty were equally effective in treating their pain as a result of a vertebral compression fracture, the American Academy of Orthopaedic Surgeons (AAOS) tells them that vertebroplasty isn’t all that effective.

AAOS/NASS Differences

In a stunning move and a seeming break with NASS, AAOS has issued new clinical guidelines recommending against the use of vertebroplasty, “for patients who present with an osteoporotic spinal compression fracture on imaging with correlating clinical signs and symptoms and who are neurologically intact.” Osteoporosis is almost universally present in older women. When the bones become weaker, vertebrae can collapse, resulting in pain, dysfunction, and sometimes deformity such as “dowager’s hump” or kyphosis.

AAOS Workgroup Guidelines

What evidence did the AAOS workgroup that developed the new guidelines come up with to reach their conclusion? As stated in the September 24 AAOS guidelines, the workgroup concluded:

The single strong recommendation in the guidelines is based on two Level I studies comparing vertebroplasty to a sham procedure, and three Level II studies comparing vertebroplasty to conservative treatment.

David Kallmes, M.D.The “sham” procedure refers to the Kallmes/Buchbinder studies published in the New England Journal of Medicine (August 2009) which found that patients receiving cement injections into the vertebral space fared about the same as patients who had a “simulated” procedure that inserted a needle into the space without injecting cement. One of those patients was a Good Sister of Assisi Heights in Minnesota.

NASS Caution of “Sham” Evidence

Shortly after the publication of those studies, NASS issued a statement cautioning against relying on the Kallmes/Buchbinder studies due to methodology shortcomings, including low enrollment. NASS, and a coalition of surgical societies, had also taken an official position on the effectiveness of vertebroplasty and kyphoplasty in a letter to CMS (Centers for Medicare and Medicaid Services) in 2008.

In that letter the coalition wrote that vertebroplasty and kyphoplasty were equally effective in reducing pain, but that kyphoplasty, with a significantly higher price tag, offered no additional value over vertebroplasty and recommended equal reimbursement for the two procedures.

Harmony of Watters

What accounts for these seemingly contradictory positions and recommendations from NASS and AAOS? 

William Watters III, M.D., MSTo find out, we sought out Bill Watters, M.D., a NASS and AAOS member whose name appeared on both organization’s recommendations. Watters is Director of the NASS Research Council and AAOS’s Guidelines and Technology Oversight Chair. Watters told us the NASS review of vertebroplasty was limited to only assessing the Kallmes and Buchbinder studies. “We said we found some shortcomings with those studies’ methodologies and suggested additional research was needed before making any formal recommendations about vertebroplasty.”

AAOS performed that additional research, and, according to Watters, used a much larger body of evidence and data to arrive at their conclusions. Watters noted however that a more recent study, Vertos II (Klazen, Lohle, et al.) was published in the August 9, 2010 edition of Lancet. That study was not included in the AAOS analysis because of its publishing date.

Vertos II Results

That study of 202 patients in the Netherlands and Belgium concluded:

In a selected subgroup of patients with acute osteoporotic vertebral fractures and persistent pain, vertebroplasty is effective and safe. Pain relief after the procedure is immediate, sustained for one year, and is significantly better than that achieved with conservative treatment and at acceptable costs.

We asked Stephen Esses, M.D., Chair of the AAOS guidelines about the additional evidence considered by the workgroup since NASS’s recommendations.

Post-NASS Evidence

Esses cited, among others, three additional studies with moderately reliable data enrolling a total of 210 patients and comparing vertebroplasty to conservative treatment. Two studies were of patients with acute injuries, while the other included patients with sub acute injuries (mean time after injury 11.6 weeks).

According to the AAOS guideline document, “In the randomized trial of patients with acute injuries, patients in both groups were offered pain medication and physiotherapy, while only patients in the conservative group were offered brace treatment. In the non-randomized trial of patients with acute injuries, all patients were offered similar analgesia and osteoporosis medications.

“In the randomized trial of patients with sub acute injuries, patients were treated with pain medication according to individual needs. Pain was significantly reduced for one day in the vertebroplasty group, but not for longer durations (the significant result at six weeks is not clinically important). Function was improved for two weeks in one study and six weeks in another, but was no longer significant beyond six months. Quality of life and analgesic-use favored the vertebroplasty group at two weeks. Fracture-related mortality was significantly reduced in the vertebroplasty group, but overall mortality was not.”

Evidence Moves On

It turns out the apparent disagreement between the two medical societies comes down to the simple notion of evidence of science moving on and making the best judgments that can be made with the data available at the time.

Don’t bury vertebroplasty just yet.

According to an August 2009 Forbes magazine article, patients may still ask for vertebroplasty no matter what the results show. “Sister Rogene Fox, an 81-year-old nun at Assisi Heights convent in Minnesota, was in the placebo group of the Mayo Clinic [Kallmes] study after getting a painful vertebra fracture in 2007. The pain went away 10 weeks after getting the placebo surgery, she says. This year, when she had a second vertebral fracture, she went back to get the real thing. Her pain went away within 10 days. ‘For me it was better, because within 10 days to two weeks my pain was considerably relieved. I would go back for another one, ‘ she says.”

And, according to Eeric Truumees, M.D., NASS board member and editor of SpineLine, Dr. Kallmes would likely perform future vertebroplasty procedures. Truumees told us that Kallmes is indeed still performing it.

“Weak” Kyphoplasty Endorsement

AAOS’ workgroup offered a tepid endorsement of kyphoplasty. The workgroup noted that the pair of Level II studies comparing kyphoplasty to conservative treatment found clinically important pain relief at various points but were still flawed. “The three studies comparing kyphoplasty to vertebroplasty had inconsistent results, ” wrote the workgroup in its guideline.

The workgroup guidelines went on to say that while kyphoplasty and vertebroplasty are similar procedures, the evidence supports treating them differently within the recommendations. “In a comparison of kyphoplasty to conservative treatment, for example, possibly clinically important differences for critical outcomes were seen for up to 12 months; comparing vertebroplasty to conservative treatment showed possibly clinically important differences for these outcomes only on the first day after surgery.”

“Additionally, a direct comparison between the two procedures showed a possibly clinically important advantage in critical outcomes for kyphoplasty at up to two years. The fact that these results were not consistent among all studies, however, lowered the confidence level that future research will confirm the results of current evidence and resulted in the ‘weak’ recommendation.”

The Academy also considered other treatments, but found, “High-quality evidence was not available to support many of the treatments currently being used for patients with osteoporotic spinal compression fractures. As a result, the work group was unable to support or oppose such common treatments as bed rest, complementary or alternative medicine, exercise, the use of analgesics or opioids, bracing, or electrical stimulation.”

NASS was listed as a participant in the peer review of the clinical practice guideline and gave its explicit consent to allow the Society’s name to be used in the recommendations. NASS, however, did not specifically endorse the guidelines. As of this writing, NASS leaders told OTW they were preparing comments on the guidelines.

The other medical societies listed as peer review participants include: the American Academy of Physical Medicine and Rehabilitation (AAPMR); the American Association of Neurological Surgeons/Congress of Neurological Surgeons (AANS/CNS Joint Section); the American College of Radiology (ACR); AO Spine International; the International Spine Intervention Society (ISIS) and the National Osteoporosis Foundation (NOF).

Industry Response

A spokesperson for Medtronic, the largest supplier of kyphoplasty products, told OTW that the company was happy to focus on the fact that kyphoplasty is now the only procedure for the treatment of vertebral compression fractures to be recommended by AAOS guidelines. A spokesperson for Stryker informed us that the company is encouraged by the results of the Vertos II study recently published by the Lancet.

Vertos IV On Horizon

Maarten Persenaire, M.D., Chief Medical Officer of Orthovita, told us that AAOS did not comment on the criticism of the Kallmes study, specifically that it did not require an MRI or bone scan to demonstrate the (sub) acute nature of the fracture seen on plain films, nor did they require pressure pain over the spinous process as part of the physical exam.

“Dr. Lohle, the senior author of Vertos II, told me last week that they are starting a new study, Vertos IV, in which they will study the same patients as in Vertos II, i.e., the ones with pain proven to be caused by (sub) acute fractures, and randomize them to the two treatment arms exactly as done by Kallmes and Buchbinder.” He added that a similar study is also being planned in Australia.

“The very public position taken by AAOS is a little surprising given the fact that the procedures are transitioning away from orthopedic surgeons and hospitals to the interventional radiologists and ambulatory centers, ” added Persenaire. 

The good Sister of Assisi Heights and Dowagers of the world can take heart that NASS and AAOS, while not yet in harmony on this topic, will nevertheless adjust and update their recommendations as science moves forward.