Elizabeth Hofheinz, M.P.H., M.Ed.
“Why,” surmised researchers at the Center for Disc Replacement at Texas Back Institute, “would orthopedic surgeons choose to perform an anterior cervical discectomy and fusion (ACDF) when cervical total disc replacement (TDR) has been reported to be similar or superior?”
With that question in mind, Richard Guyer, M.D., Donna Ohnmeiss, Ph.D., Scott Blumenthal, M.D. and Jack Zigler, M.D. examined the records of 464 patients undergoing cervical spine surgery over a 5-year period by three TDR specialty surgeons.
The authors referenced a prior related study which determined that 47% of patients who underwent ACDF would have qualified for TDR1, noting that the specific reasons for selecting ACDF rather than TDR were not given.
Dr. Guyer told OSN, “We were curious to determine what percentage of patients that we were seeing in our clinics for consideration of cervical arthroplasty ended up having anterior cervical discectomy and fusion (ACDF).”
It turned out that approximately 25% of patients underwent ACDF.
“TDR was performed in 76.7% of patients (n = 356) and ACDF in 23.3% (n = 108),” wrote the authors. “The most common reason for ACDF versus TDR was anatomical (conditions that may not be adequately addressed with TDR and/or may interfere with device function), which occurred in 64 of 464 patients (13.79%). The second most common reason was insurance (denial/lack of coverage n = 17, 3.23%), and deformity/kyphosis not addressable with TDR was noted in 13 (2.80%). Pseudoarthrosis repair led to ACDF in three patients (0.65%), two did not receive TDR due to osteoporosis (0.43%), and in two others (0.43%) ACDF was undertaken due to high risk of heterotopic ossification. There was one case (0.22%) each of: nickel allergy, trauma with posterior element fracture, TDR removal, multiple prior cervical spine surgeries, concern about artifact on future imaging studies, benign osteoblastic bone, and limitation to adequate surgical approach for TDR. ACDF patients’ mean age was significantly greater than TDR patients’ (55.3 vs. 46.7 years). TDR group had significantly more single-level procedures than ACDF (60.8% vs. 43.5%).”
Dr. Guyer told OSN, “Even using strict criteria for cervical disc replacement, the most common reasons for ACDF were anatomic factors that may compromise stability, older age, and greater number of operated levels which may be related to the presence of significant osteophytes and severely degenerated facets. These factors, as well as deformity/kyphosis, are more common in older patients and require multi-level treatment. This study found that the majority of patients are good cervical TDR candidates, but even among TDR specialists, ACDF may be preferred.”
Asked how this work might advance the field, Dr. Guyer commented to OSN, “I believe that it will help spur the development of future implants so more of these patients who had fusions would be able to benefit from arthroplasty. Also, it emphasizes the need for careful pre-operative evaluation of the anatomy. We are now obtaining more and more CT scans to accurately delineate the bony anatomy.”