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Two-level TDR yields similar outcomes to single-level procedures
Surgeons using the ProDisc discovered comparable function and patient satisfaction.
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Researchers examining 128 randomized patients found similar results comparing two-level disc arthroplasties using the ProDisc and single-level procedures with the same device.
“At two to three-year follow up, the two-level ProDisc (Synthes) patients do as well as single levels regarding pain and function,” said Jack E. Zigler, MD, a surgeon at the Texas Back Institute. “Increased OR time, blood loss, [and] length of stay are within acceptable limits, and patient satisfaction is similar,” he said during his presentation at the North American Spine Society 20th Annual Meeting.
Zigler and his colleagues studied 88 patients who received a single-level total disc arthroplasty and 48 patients who had two-level procedures. The one level cohort contained more men, while the multilevel group had equivalent numbers of men and women. “The average age was a little bit older in the two-level degenerative disease population, which is what you’d expect,” said Zigler, who is also a Synthes consultant and stockholder. All patients received ProDisc implants.
Immediate drop in pain
Courtesy of Jack E. Zigler |
The researchers discovered a significant drop in Visual Analog Scale scores from preoperative measures to six-week follow-up. But they noted no significant differences between the groups from six-week to two-year follow-up. “The mean improvement in two-level cases was 58.7% and in one-level cases 62.4% (P>.05),” the researchers wrote in their abstract.
“Similarly, if we look at Oswestry for functional disability, there’s a significant drop immediately postoperatively, but then at each of the individual study visits out to two years, there’s no significant difference between the one- and two-level cases,” Zigler said.
The researchers also assessed function through bending exercises. “If we look at bending inches from the floor in forward bending, we can see that preoperatively the two-level degenerative patients are a little stiffer and that postoperatively, they stay a little bit stiffer, but not statistically so,” he said.
Patient satisfaction scores remained equivalent up to two-year follow-up. On a 10-point scale, single-level patients reported a mean score of 8.2 while the two-level group reported a mean score of 7.1.
Six re-operations
Surgeons spent similar time performing the procedures. One-level arthroplasty took an average of 61 minutes and multilevel operations showed an average OR time of 94 minutes, Zigler said.
The groups exhibited comparable blood loss, too. Patients with a single-level arthroplasty lost an average 57.7 cc of blood. The two-level patients demonstrated an average loss of 81.9 cc, the researchers wrote. They found no significant differences in hospital stay. Single-level arthroplasty patients stayed an average 1.86 days vs. 2.36 days for the multilevel cohort.
The researchers noted no paralysis, death or implant migration, but experienced one complication from deep vein thrombosis. The surgeons performed six re-operations. “One was technical,” Zigler said. “Two required decompressions, which were negative. The other was a dorsal column stimulator. Other cases included one fracture and one pars interarticularis repair.
Zigler’s results are part of a multicenter study including 161 ProDisc patients at his study site. The study, which began in 2001, has begun to highlight the effectiveness of multilevel disc arthroplasty. “In appropriately selected patients, the two-level arthroplasty offers results similar to one, but only time will tell if multiple-level arthroplasty will protect patients better than multiple-level fusion.”
For more information:
- Zigler J, Sachs B, Rashbaum R, et al. Two-level total disc replacement with ProDisc: results and comparison to one-level cases. #9. Presented at the North American Spine Society 20th Annual Meeting. Sept. 27-Oct. 1, 2005. Philadelphia.