AAOS Now

Published 12/1/2008
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Annie Hayashi

Total disk arthroplasty: Not the panacea some hope for

Award-winning study challenges broad use of TDA as alternative for fusion

Total disk arthroplasty (TDA) is appealing to both surgeons and patients because it promises to preserve motion while reducing discogenic pain and adjacent segment degeneration. But whether it is a viable alternative to spinal fusion is still undetermined.

According to a study presented by David A. Wong, MD, MS, FRCS(C), at the 2008 annual meeting of the North American Spine Society, many candidates for spinal fusion may have several “relative and decisive” contraindications to TDA.

Contraindications to TDA
Dr. Wong and his colleagues based their study on an earlier study by Russell C. Huang, MD, and Frank P. Cammisa, MD, at New York’s Hospital for Special Surgery. Because the earlier study was limited to a single surgeon and institution, Dr. Wong hoped his retrospective review would clarify the findings and determine whether they had wider application.

Facet arthrosis, a recognized contraindication, was a common finding in the earlier study (Table 1). Dr. Wong focused his study on the clinical significance of facet arthrosis because it has a “relatively imprecise diagnosis.” According to him, facet arthrosis “was most likely to represent a patient selection dilemma for the spine surgeon.”

Review shows impact of facet arthrosis
Dr. Wong and his colleagues examined 100 sets of patient records—including clinical notes, imaging reports, injection reports, and operating room reports—for indications of facet arthrosis. They found facet arthrosis in 97 percent of cases. The highest incidence of facet disease was found on operating reports (
Fig. 1).

Patients with facet arthrosis were then divided into subgroups based on physical examination findings and the results of injections to determine whether their facet disease was significant enough to be a contraindication to TDA (Table 2). Most patients (85 out of 100) had clinically significant levels of facet degeneration.

The chart review also revealed that patients had an average of 3.69 contraindications for TDA. Spondylolisthesis, the second most common contraindication, was found in three out of four patients; central spinal stenosis was identified in 72 of the 100 patients. Other conditions occurred in 30 percent or less of patients.

“A major challenge facing physicians evaluating potential candidates for TDA will be identifying the subgroup of patients who have clinically significant facet pathology,” said Dr. Wong.

“Incidence of contraindications to total disc arthroplasty: A retrospective review of 100 consecutive fusion patients with a specific analysis of facet arthrosis” received the 2008 Editors’ Choice Award from The Spine Journal. Authors are David A. Wong, MD, MSc, FRCS(C); Betsy Annesser, DPt; Timothy J. Birney, MD; Roderick Lamond, MD, FRCS(C); Anant Kumar, MD; Stephen Johnson, MD; Sanjay Jatana, MD; and Gary Ghiselli, MD.

Dr. Wong has ties to Neurotech, Anulex, Stryker, Zimmer, Cervitech, and Abbott. Timothy J. Birney, MD; Anant Kumar, MD; Sanjay Jatana, MD; and Gary Ghiselli, MD, have no disclosures. Dis­closure information for neuro­­­surgeons Roderick Lamond, MD, FRCS(C), and Stephen Johnson, MD, and for physical therapist Betsy Annesser, DPt, is not available.

Annie Hayashi is the senior science writer for AAOS Now. She can be reached at hayashi@aaos.org